Merge remote-tracking branch 'upstream/master' into csharp_upgrade_to_proto3

Conflicts:
	src/csharp/Grpc.IntegrationTesting/InteropClient.cs

405 files changed, 14707 insertions, 2515 deletions

diff --git a/src/compiler/config.h b/src/compiler/config.h
index cd52aca57d..fea976c318 100644
--- a/src/compiler/config.h
+++ b/src/compiler/config.h
@@ -34,8 +34,8 @@
 #ifndef SRC_COMPILER_CONFIG_H
 #define SRC_COMPILER_CONFIG_H
 
-#include <grpc++/config.h>
-#include <grpc++/config_protobuf.h>
+#include <grpc++/support/config.h>
+#include <grpc++/support/config_protobuf.h>
 
 #ifndef GRPC_CUSTOM_DESCRIPTOR
 #include <google/protobuf/descriptor.h>
diff --git a/src/compiler/cpp_generator.cc b/src/compiler/cpp_generator.cc
index ea487bcd89..1bf2b16ed6 100644
--- a/src/compiler/cpp_generator.cc
+++ b/src/compiler/cpp_generator.cc
@@ -112,18 +112,18 @@ grpc::string GetHeaderPrologue(const grpc::protobuf::FileDescriptor *file,
 grpc::string GetHeaderIncludes(const grpc::protobuf::FileDescriptor *file,
                                const Parameters &params) {
   grpc::string temp =
-      "#include <grpc++/impl/internal_stub.h>\n"
+      "#include <grpc++/support/async_stream.h>\n"
       "#include <grpc++/impl/rpc_method.h>\n"
       "#include <grpc++/impl/proto_utils.h>\n"
       "#include <grpc++/impl/service_type.h>\n"
-      "#include <grpc++/async_unary_call.h>\n"
-      "#include <grpc++/status.h>\n"
-      "#include <grpc++/stream.h>\n"
-      "#include <grpc++/stub_options.h>\n"
+      "#include <grpc++/support/async_unary_call.h>\n"
+      "#include <grpc++/support/status.h>\n"
+      "#include <grpc++/support/stub_options.h>\n"
+      "#include <grpc++/support/sync_stream.h>\n"
       "\n"
       "namespace grpc {\n"
       "class CompletionQueue;\n"
-      "class ChannelInterface;\n"
+      "class Channel;\n"
       "class RpcService;\n"
       "class ServerCompletionQueue;\n"
       "class ServerContext;\n"
@@ -554,17 +554,17 @@ void PrintHeaderService(grpc::protobuf::io::Printer *printer,
   printer->Outdent();
   printer->Print("};\n");
   printer->Print(
-      "class Stub GRPC_FINAL : public StubInterface,"
-      " public ::grpc::InternalStub {\n public:\n");
+      "class Stub GRPC_FINAL : public StubInterface"
+      " {\n public:\n");
   printer->Indent();
-  printer->Print(
-      "Stub(const std::shared_ptr< ::grpc::ChannelInterface>& channel);\n");
+  printer->Print("Stub(const std::shared_ptr< ::grpc::Channel>& channel);\n");
   for (int i = 0; i < service->method_count(); ++i) {
     PrintHeaderClientMethod(printer, service->method(i), vars, true);
   }
   printer->Outdent();
   printer->Print("\n private:\n");
   printer->Indent();
+  printer->Print("std::shared_ptr< ::grpc::Channel> channel_;\n");
   for (int i = 0; i < service->method_count(); ++i) {
     PrintHeaderClientMethod(printer, service->method(i), vars, false);
   }
@@ -575,7 +575,7 @@ void PrintHeaderService(grpc::protobuf::io::Printer *printer,
   printer->Print("};\n");
   printer->Print(
       "static std::unique_ptr<Stub> NewStub(const std::shared_ptr< "
-      "::grpc::ChannelInterface>& channel, "
+      "::grpc::Channel>& channel, "
       "const ::grpc::StubOptions& options = ::grpc::StubOptions());\n");
 
   printer->Print("\n");
@@ -702,12 +702,13 @@ grpc::string GetSourceIncludes(const grpc::protobuf::FileDescriptor *file,
     grpc::protobuf::io::Printer printer(&output_stream, '$');
     std::map<grpc::string, grpc::string> vars;
 
-    printer.Print(vars, "#include <grpc++/async_unary_call.h>\n");
-    printer.Print(vars, "#include <grpc++/channel_interface.h>\n");
+    printer.Print(vars, "#include <grpc++/channel.h>\n");
     printer.Print(vars, "#include <grpc++/impl/client_unary_call.h>\n");
     printer.Print(vars, "#include <grpc++/impl/rpc_service_method.h>\n");
     printer.Print(vars, "#include <grpc++/impl/service_type.h>\n");
-    printer.Print(vars, "#include <grpc++/stream.h>\n");
+    printer.Print(vars, "#include <grpc++/support/async_unary_call.h>\n");
+    printer.Print(vars, "#include <grpc++/support/async_stream.h>\n");
+    printer.Print(vars, "#include <grpc++/support/sync_stream.h>\n");
 
     if (!file->package().empty()) {
       std::vector<grpc::string> parts =
@@ -738,7 +739,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::ClientContext* context, "
                    "const $Request$& request, $Response$* response) {\n");
     printer->Print(*vars,
-                   "  return ::grpc::BlockingUnaryCall(channel(), "
+                   "  return ::grpc::BlockingUnaryCall(channel_.get(), "
                    "rpcmethod_$Method$_, "
                    "context, request, response);\n"
                    "}\n\n");
@@ -751,7 +752,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
     printer->Print(*vars,
                    "  return new "
                    "::grpc::ClientAsyncResponseReader< $Response$>("
-                   "channel(), cq, "
+                   "channel_.get(), cq, "
                    "rpcmethod_$Method$_, "
                    "context, request);\n"
                    "}\n\n");
@@ -762,7 +763,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::ClientContext* context, $Response$* response) {\n");
     printer->Print(*vars,
                    "  return new ::grpc::ClientWriter< $Request$>("
-                   "channel(), "
+                   "channel_.get(), "
                    "rpcmethod_$Method$_, "
                    "context, response);\n"
                    "}\n\n");
@@ -773,7 +774,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::CompletionQueue* cq, void* tag) {\n");
     printer->Print(*vars,
                    "  return new ::grpc::ClientAsyncWriter< $Request$>("
-                   "channel(), cq, "
+                   "channel_.get(), cq, "
                    "rpcmethod_$Method$_, "
                    "context, response, tag);\n"
                    "}\n\n");
@@ -785,7 +786,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
         "::grpc::ClientContext* context, const $Request$& request) {\n");
     printer->Print(*vars,
                    "  return new ::grpc::ClientReader< $Response$>("
-                   "channel(), "
+                   "channel_.get(), "
                    "rpcmethod_$Method$_, "
                    "context, request);\n"
                    "}\n\n");
@@ -796,7 +797,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::CompletionQueue* cq, void* tag) {\n");
     printer->Print(*vars,
                    "  return new ::grpc::ClientAsyncReader< $Response$>("
-                   "channel(), cq, "
+                   "channel_.get(), cq, "
                    "rpcmethod_$Method$_, "
                    "context, request, tag);\n"
                    "}\n\n");
@@ -808,7 +809,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
     printer->Print(*vars,
                    "  return new ::grpc::ClientReaderWriter< "
                    "$Request$, $Response$>("
-                   "channel(), "
+                   "channel_.get(), "
                    "rpcmethod_$Method$_, "
                    "context);\n"
                    "}\n\n");
@@ -820,7 +821,7 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
     printer->Print(*vars,
                    "  return new "
                    "::grpc::ClientAsyncReaderWriter< $Request$, $Response$>("
-                   "channel(), cq, "
+                   "channel_.get(), cq, "
                    "rpcmethod_$Method$_, "
                    "context, tag);\n"
                    "}\n\n");
@@ -964,20 +965,19 @@ void PrintSourceService(grpc::protobuf::io::Printer *printer,
   }
   printer->Print(*vars, "};\n\n");
 
-  printer->Print(
-      *vars,
-      "std::unique_ptr< $ns$$Service$::Stub> $ns$$Service$::NewStub("
-      "const std::shared_ptr< ::grpc::ChannelInterface>& channel, "
-      "const ::grpc::StubOptions& options) {\n"
-      "  std::unique_ptr< $ns$$Service$::Stub> stub(new "
-      "$ns$$Service$::Stub(channel));\n"
-      "  return stub;\n"
-      "}\n\n");
+  printer->Print(*vars,
+                 "std::unique_ptr< $ns$$Service$::Stub> $ns$$Service$::NewStub("
+                 "const std::shared_ptr< ::grpc::Channel>& channel, "
+                 "const ::grpc::StubOptions& options) {\n"
+                 "  std::unique_ptr< $ns$$Service$::Stub> stub(new "
+                 "$ns$$Service$::Stub(channel));\n"
+                 "  return stub;\n"
+                 "}\n\n");
   printer->Print(*vars,
                  "$ns$$Service$::Stub::Stub(const std::shared_ptr< "
-                 "::grpc::ChannelInterface>& channel)\n");
+                 "::grpc::Channel>& channel)\n");
   printer->Indent();
-  printer->Print(": ::grpc::InternalStub(channel)");
+  printer->Print(": channel_(channel)");
   for (int i = 0; i < service->method_count(); ++i) {
     const grpc::protobuf::MethodDescriptor *method = service->method(i);
     (*vars)["Method"] = method->name();
@@ -991,13 +991,12 @@ void PrintSourceService(grpc::protobuf::io::Printer *printer,
     } else {
       (*vars)["StreamingType"] = "BIDI_STREAMING";
     }
-    printer->Print(
-        *vars,
-        ", rpcmethod_$Method$_("
-        "$prefix$$Service$_method_names[$Idx$], "
-        "::grpc::RpcMethod::$StreamingType$, "
-        "channel->RegisterMethod($prefix$$Service$_method_names[$Idx$])"
-        ")\n");
+    printer->Print(*vars,
+                   ", rpcmethod_$Method$_("
+                   "$prefix$$Service$_method_names[$Idx$], "
+                   "::grpc::RpcMethod::$StreamingType$, "
+                   "channel"
+                   ")\n");
   }
   printer->Print("{}\n\n");
   printer->Outdent();
diff --git a/src/compiler/objective_c_generator.cc b/src/compiler/objective_c_generator.cc
index 483c6573a8..a3157db0fb 100644
--- a/src/compiler/objective_c_generator.cc
+++ b/src/compiler/objective_c_generator.cc
@@ -44,7 +44,6 @@ using ::google::protobuf::compiler::objectivec::ClassName;
 using ::grpc::protobuf::io::Printer;
 using ::grpc::protobuf::MethodDescriptor;
 using ::grpc::protobuf::ServiceDescriptor;
-using ::grpc::string;
 using ::std::map;
 
 namespace grpc_objective_c_generator {
@@ -52,7 +51,7 @@ namespace {
 
 void PrintProtoRpcDeclarationAsPragma(Printer *printer,
                                       const MethodDescriptor *method,
-                                      map<string, string> vars) {
+                                      map< ::grpc::string, ::grpc::string> vars) {
   vars["client_stream"] = method->client_streaming() ? "stream " : "";
   vars["server_stream"] = method->server_streaming() ? "stream " : "";
 
@@ -62,7 +61,7 @@ void PrintProtoRpcDeclarationAsPragma(Printer *printer,
 }
 
 void PrintMethodSignature(Printer *printer, const MethodDescriptor *method,
-                          const map<string, string> &vars) {
+                          const map< ::grpc::string, ::grpc::string> &vars) {
   // TODO(jcanizales): Print method comments.
 
   printer->Print(vars, "- ($return_type$)$method_name$With");
@@ -85,7 +84,7 @@ void PrintMethodSignature(Printer *printer, const MethodDescriptor *method,
 }
 
 void PrintSimpleSignature(Printer *printer, const MethodDescriptor *method,
-                          map<string, string> vars) {
+                          map< ::grpc::string, ::grpc::string> vars) {
   vars["method_name"] =
       grpc_generator::LowercaseFirstLetter(vars["method_name"]);
   vars["return_type"] = "void";
@@ -93,14 +92,14 @@ void PrintSimpleSignature(Printer *printer, const MethodDescriptor *method,
 }
 
 void PrintAdvancedSignature(Printer *printer, const MethodDescriptor *method,
-                            map<string, string> vars) {
+                            map< ::grpc::string, ::grpc::string> vars) {
   vars["method_name"] = "RPCTo" + vars["method_name"];
   vars["return_type"] = "ProtoRPC *";
   PrintMethodSignature(printer, method, vars);
 }
 
-inline map<string, string> GetMethodVars(const MethodDescriptor *method) {
-  map<string, string> res;
+inline map< ::grpc::string, ::grpc::string> GetMethodVars(const MethodDescriptor *method) {
+  map< ::grpc::string, ::grpc::string> res;
   res["method_name"] = method->name();
   res["request_type"] = method->input_type()->name();
   res["response_type"] = method->output_type()->name();
@@ -110,7 +109,7 @@ inline map<string, string> GetMethodVars(const MethodDescriptor *method) {
 }
 
 void PrintMethodDeclarations(Printer *printer, const MethodDescriptor *method) {
-  map<string, string> vars = GetMethodVars(method);
+  map< ::grpc::string, ::grpc::string> vars = GetMethodVars(method);
 
   PrintProtoRpcDeclarationAsPragma(printer, method, vars);
 
@@ -121,7 +120,7 @@ void PrintMethodDeclarations(Printer *printer, const MethodDescriptor *method) {
 }
 
 void PrintSimpleImplementation(Printer *printer, const MethodDescriptor *method,
-                               map<string, string> vars) {
+                               map< ::grpc::string, ::grpc::string> vars) {
   printer->Print("{\n");
   printer->Print(vars, "  [[self RPCTo$method_name$With");
   if (method->client_streaming()) {
@@ -139,7 +138,7 @@ void PrintSimpleImplementation(Printer *printer, const MethodDescriptor *method,
 
 void PrintAdvancedImplementation(Printer *printer,
                                  const MethodDescriptor *method,
-                                 map<string, string> vars) {
+                                 map< ::grpc::string, ::grpc::string> vars) {
   printer->Print("{\n");
   printer->Print(vars, "  return [self RPCToMethod:@\"$method_name$\"\n");
 
@@ -164,7 +163,7 @@ void PrintAdvancedImplementation(Printer *printer,
 
 void PrintMethodImplementations(Printer *printer,
                                 const MethodDescriptor *method) {
-  map<string, string> vars = GetMethodVars(method);
+  map< ::grpc::string, ::grpc::string> vars = GetMethodVars(method);
 
   PrintProtoRpcDeclarationAsPragma(printer, method, vars);
 
@@ -179,14 +178,14 @@ void PrintMethodImplementations(Printer *printer,
 
 }  // namespace
 
-string GetHeader(const ServiceDescriptor *service) {
-  string output;
+::grpc::string GetHeader(const ServiceDescriptor *service) {
+  ::grpc::string output;
   {
     // Scope the output stream so it closes and finalizes output to the string.
     grpc::protobuf::io::StringOutputStream output_stream(&output);
     Printer printer(&output_stream, '$');
 
-    map<string, string> vars = {{"service_class", ServiceClassName(service)}};
+    map< ::grpc::string, ::grpc::string> vars = {{"service_class", ServiceClassName(service)}};
 
     printer.Print(vars, "@protocol $service_class$ <NSObject>\n\n");
 
@@ -209,14 +208,14 @@ string GetHeader(const ServiceDescriptor *service) {
   return output;
 }
 
-string GetSource(const ServiceDescriptor *service) {
-  string output;
+::grpc::string GetSource(const ServiceDescriptor *service) {
+ ::grpc::string output;
   {
     // Scope the output stream so it closes and finalizes output to the string.
     grpc::protobuf::io::StringOutputStream output_stream(&output);
     Printer printer(&output_stream, '$');
 
-    map<string, string> vars = {{"service_name", service->name()},
+    map< ::grpc::string,::grpc::string> vars = {{"service_name", service->name()},
                                 {"service_class", ServiceClassName(service)},
                                 {"package", service->file()->package()}};
 
diff --git a/src/compiler/objective_c_plugin.cc b/src/compiler/objective_c_plugin.cc
index 10f06ad4df..17440358bb 100644
--- a/src/compiler/objective_c_plugin.cc
+++ b/src/compiler/objective_c_plugin.cc
@@ -39,44 +39,43 @@
 #include "src/compiler/objective_c_generator.h"
 #include "src/compiler/objective_c_generator_helpers.h"
 
-using ::grpc::string;
-
 class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
  public:
   ObjectiveCGrpcGenerator() {}
   virtual ~ObjectiveCGrpcGenerator() {}
 
   virtual bool Generate(const grpc::protobuf::FileDescriptor *file,
-                        const string &parameter,
+                        const ::grpc::string &parameter,
                         grpc::protobuf::compiler::GeneratorContext *context,
-                        string *error) const {
+                        ::grpc::string *error) const {
 
     if (file->service_count() == 0) {
       // No services.  Do nothing.
       return true;
     }
 
-    string file_name = grpc_generator::FileNameInUpperCamel(file);
-    string prefix = file->options().objc_class_prefix();
+    ::grpc::string file_name = grpc_generator::FileNameInUpperCamel(file);
+    ::grpc::string prefix = file->options().objc_class_prefix();
 
     {
       // Generate .pbrpc.h
 
-      string imports = string("#import \"") + file_name + ".pbobjc.h\"\n\n"
+      ::grpc::string imports = ::grpc::string("#import \"") + file_name +
+        ".pbobjc.h\"\n\n"
         "#import <ProtoRPC/ProtoService.h>\n"
         "#import <RxLibrary/GRXWriteable.h>\n"
         "#import <RxLibrary/GRXWriter.h>\n";
 
       // TODO(jcanizales): Instead forward-declare the input and output types
       // and import the files in the .pbrpc.m
-      string proto_imports;
+      ::grpc::string proto_imports;
       for (int i = 0; i < file->dependency_count(); i++) {
-        string header = grpc_objective_c_generator::MessageHeaderName(
+        ::grpc::string header = grpc_objective_c_generator::MessageHeaderName(
             file->dependency(i));
-        proto_imports += string("#import \"") + header + "\"\n";
+        proto_imports += ::grpc::string("#import \"") + header + "\"\n";
       }
 
-      string declarations;
+      ::grpc::string declarations;
       for (int i = 0; i < file->service_count(); i++) {
         const grpc::protobuf::ServiceDescriptor *service = file->service(i);
         declarations += grpc_objective_c_generator::GetHeader(service);
@@ -89,11 +88,12 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
     {
       // Generate .pbrpc.m
 
-      string imports = string("#import \"") + file_name + ".pbrpc.h\"\n\n"
+      ::grpc::string imports = ::grpc::string("#import \"") + file_name +
+        ".pbrpc.h\"\n\n"
         "#import <ProtoRPC/ProtoRPC.h>\n"
         "#import <RxLibrary/GRXWriter+Immediate.h>\n";
 
-      string definitions;
+      ::grpc::string definitions;
       for (int i = 0; i < file->service_count(); i++) {
         const grpc::protobuf::ServiceDescriptor *service = file->service(i);
         definitions += grpc_objective_c_generator::GetSource(service);
@@ -108,7 +108,7 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
  private:
   // Write the given code into the given file.
   void Write(grpc::protobuf::compiler::GeneratorContext *context,
-              const string &filename, const string &code) const {
+              const ::grpc::string &filename, const ::grpc::string &code) const {
     std::unique_ptr<grpc::protobuf::io::ZeroCopyOutputStream> output(
         context->Open(filename));
     grpc::protobuf::io::CodedOutputStream coded_out(output.get());
diff --git a/src/compiler/python_generator.cc b/src/compiler/python_generator.cc
index 2982a89fad..72c457ac6b 100644
--- a/src/compiler/python_generator.cc
+++ b/src/compiler/python_generator.cc
@@ -42,7 +42,7 @@
 #include <tuple>
 #include <vector>
 
-#include <grpc++/config.h>
+#include <grpc++/support/config.h>
 #include "src/compiler/config.h"
 #include "src/compiler/generator_helpers.h"
 #include "src/compiler/python_generator.h"
diff --git a/src/core/channel/census_filter.c b/src/core/census/grpc_filter.c
index d996c3475e..fbedb35661 100644
--- a/src/core/channel/census_filter.c
+++ b/src/core/census/grpc_filter.c
@@ -31,11 +31,13 @@
  *
  */
 
-#include "src/core/channel/census_filter.h"
+#include "src/core/census/grpc_filter.h"
 
 #include <stdio.h>
 #include <string.h>
 
+#include "include/grpc/census.h"
+#include "src/core/census/rpc_stat_id.h"
 #include "src/core/channel/channel_stack.h"
 #include "src/core/channel/noop_filter.h"
 #include "src/core/statistics/census_interface.h"
@@ -47,24 +49,19 @@
 
 typedef struct call_data {
   census_op_id op_id;
-  census_rpc_stats stats;
+  census_context* ctxt;
   gpr_timespec start_ts;
+  int error;
 
   /* recv callback */
   grpc_stream_op_buffer* recv_ops;
-  void (*on_done_recv)(void* user_data, int success);
-  void* recv_user_data;
+  grpc_iomgr_closure* on_done_recv;
 } call_data;
 
 typedef struct channel_data {
   grpc_mdstr* path_str; /* pointer to meta data str with key == ":path" */
 } channel_data;
 
-static void init_rpc_stats(census_rpc_stats* stats) {
-  memset(stats, 0, sizeof(census_rpc_stats));
-  stats->cnt = 1;
-}
-
 static void extract_and_annotate_method_tag(grpc_stream_op_buffer* sopb,
                                             call_data* calld,
                                             channel_data* chand) {
@@ -77,8 +74,7 @@ static void extract_and_annotate_method_tag(grpc_stream_op_buffer* sopb,
       if (m->md->key == chand->path_str) {
         gpr_log(GPR_DEBUG, "%s",
                 (const char*)GPR_SLICE_START_PTR(m->md->value->slice));
-        census_add_method_tag(calld->op_id, (const char*)GPR_SLICE_START_PTR(
-                                                m->md->value->slice));
+        /* Add method tag here */
       }
     }
   }
@@ -95,8 +91,6 @@ static void client_mutate_op(grpc_call_element* elem,
 
 static void client_start_transport_op(grpc_call_element* elem,
                                       grpc_transport_stream_op* op) {
-  call_data* calld = elem->call_data;
-  GPR_ASSERT((calld->op_id.upper != 0) || (calld->op_id.lower != 0));
   client_mutate_op(elem, op);
   grpc_call_next_op(elem, op);
 }
@@ -108,7 +102,7 @@ static void server_on_done_recv(void* ptr, int success) {
   if (success) {
     extract_and_annotate_method_tag(calld->recv_ops, calld, chand);
   }
-  calld->on_done_recv(calld->recv_user_data, success);
+  calld->on_done_recv->cb(calld->on_done_recv->cb_arg, success);
 }
 
 static void server_mutate_op(grpc_call_element* elem,
@@ -118,9 +112,7 @@ static void server_mutate_op(grpc_call_element* elem,
     /* substitute our callback for the op callback */
     calld->recv_ops = op->recv_ops;
     calld->on_done_recv = op->on_done_recv;
-    calld->recv_user_data = op->recv_user_data;
-    op->on_done_recv = server_on_done_recv;
-    op->recv_user_data = elem;
+    op->on_done_recv = calld->on_done_recv;
   }
 }
 
@@ -132,35 +124,19 @@ static void server_start_transport_op(grpc_call_element* elem,
   grpc_call_next_op(elem, op);
 }
 
-static void channel_op(grpc_channel_element* elem,
-                       grpc_channel_element* from_elem, grpc_channel_op* op) {
-  switch (op->type) {
-    case GRPC_TRANSPORT_CLOSED:
-      /* TODO(hongyu): Annotate trace information for all calls of the channel
-       */
-      break;
-    default:
-      break;
-  }
-  grpc_channel_next_op(elem, op);
-}
-
 static void client_init_call_elem(grpc_call_element* elem,
                                   const void* server_transport_data,
                                   grpc_transport_stream_op* initial_op) {
   call_data* d = elem->call_data;
   GPR_ASSERT(d != NULL);
-  init_rpc_stats(&d->stats);
   d->start_ts = gpr_now(GPR_CLOCK_REALTIME);
-  d->op_id = census_tracing_start_op();
   if (initial_op) client_mutate_op(elem, initial_op);
 }
 
 static void client_destroy_call_elem(grpc_call_element* elem) {
   call_data* d = elem->call_data;
   GPR_ASSERT(d != NULL);
-  census_record_rpc_client_stats(d->op_id, &d->stats);
-  census_tracing_end_op(d->op_id);
+  /* TODO(hongyu): record rpc client stats and census_rpc_end_op here */
 }
 
 static void server_init_call_elem(grpc_call_element* elem,
@@ -168,29 +144,24 @@ static void server_init_call_elem(grpc_call_element* elem,
                                   grpc_transport_stream_op* initial_op) {
   call_data* d = elem->call_data;
   GPR_ASSERT(d != NULL);
-  init_rpc_stats(&d->stats);
   d->start_ts = gpr_now(GPR_CLOCK_REALTIME);
-  d->op_id = census_tracing_start_op();
+  /* TODO(hongyu): call census_tracing_start_op here. */
+  grpc_iomgr_closure_init(d->on_done_recv, server_on_done_recv, elem);
   if (initial_op) server_mutate_op(elem, initial_op);
 }
 
 static void server_destroy_call_elem(grpc_call_element* elem) {
   call_data* d = elem->call_data;
   GPR_ASSERT(d != NULL);
-  d->stats.elapsed_time_ms = gpr_timespec_to_micros(
-      gpr_time_sub(gpr_now(GPR_CLOCK_REALTIME), d->start_ts));
-  census_record_rpc_server_stats(d->op_id, &d->stats);
-  census_tracing_end_op(d->op_id);
+  /* TODO(hongyu): record rpc server stats and census_tracing_end_op here */
 }
 
-static void init_channel_elem(grpc_channel_element* elem,
+static void init_channel_elem(grpc_channel_element* elem, grpc_channel* master,
                               const grpc_channel_args* args, grpc_mdctx* mdctx,
                               int is_first, int is_last) {
   channel_data* chand = elem->channel_data;
   GPR_ASSERT(chand != NULL);
-  GPR_ASSERT(!is_first);
-  GPR_ASSERT(!is_last);
-  chand->path_str = grpc_mdstr_from_string(mdctx, ":path");
+  chand->path_str = grpc_mdstr_from_string(mdctx, ":path", 0);
 }
 
 static void destroy_channel_elem(grpc_channel_element* elem) {
@@ -203,22 +174,24 @@ static void destroy_channel_elem(grpc_channel_element* elem) {
 
 const grpc_channel_filter grpc_client_census_filter = {
     client_start_transport_op,
-    channel_op,
+    grpc_channel_next_op,
     sizeof(call_data),
     client_init_call_elem,
     client_destroy_call_elem,
     sizeof(channel_data),
     init_channel_elem,
     destroy_channel_elem,
+    grpc_call_next_get_peer,
     "census-client"};
 
 const grpc_channel_filter grpc_server_census_filter = {
     server_start_transport_op,
-    channel_op,
+    grpc_channel_next_op,
     sizeof(call_data),
     server_init_call_elem,
     server_destroy_call_elem,
     sizeof(channel_data),
     init_channel_elem,
     destroy_channel_elem,
+    grpc_call_next_get_peer,
     "census-server"};
diff --git a/src/core/channel/census_filter.h b/src/core/census/grpc_filter.h
index 4f9759f0db..1453c05d28 100644
--- a/src/core/channel/census_filter.h
+++ b/src/core/census/grpc_filter.h
@@ -41,4 +41,4 @@
 extern const grpc_channel_filter grpc_client_census_filter;
 extern const grpc_channel_filter grpc_server_census_filter;
 
-#endif  /* GRPC_INTERNAL_CORE_CHANNEL_CENSUS_FILTER_H */
+#endif /* GRPC_INTERNAL_CORE_CHANNEL_CENSUS_FILTER_H */
diff --git a/src/core/channel/channel_args.c b/src/core/channel/channel_args.c
index c430b56fa2..54ee75af28 100644
--- a/src/core/channel/channel_args.c
+++ b/src/core/channel/channel_args.c
@@ -37,6 +37,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
 
 #include <string.h>
 
@@ -146,3 +147,65 @@ grpc_channel_args *grpc_channel_args_set_compression_algorithm(
   tmp.value.integer = algorithm;
   return grpc_channel_args_copy_and_add(a, &tmp, 1);
 }
+
+/** Returns 1 if the argument for compression algorithm's enabled states bitset
+ * was found in \a a, returning the arg's value in \a states. Otherwise, returns
+ * 0. */
+static int find_compression_algorithm_states_bitset(
+    const grpc_channel_args *a, int **states_arg) {
+  if (a != NULL) {
+    size_t i;
+    for (i = 0; i < a->num_args; ++i) {
+      if (a->args[i].type == GRPC_ARG_INTEGER &&
+          !strcmp(GRPC_COMPRESSION_ALGORITHM_STATE_ARG, a->args[i].key)) {
+        *states_arg = &a->args[i].value.integer;
+        return 1; /* GPR_TRUE */
+      }
+    }
+  }
+  return 0; /* GPR_FALSE */
+}
+
+grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
+    grpc_channel_args **a,
+    grpc_compression_algorithm algorithm,
+    int state) {
+  int *states_arg;
+  grpc_channel_args *result = *a;
+  const int states_arg_found =
+      find_compression_algorithm_states_bitset(*a, &states_arg);
+
+  if (states_arg_found) {
+    if (state != 0) {
+      GPR_BITSET(states_arg, algorithm);
+    } else {
+      GPR_BITCLEAR(states_arg, algorithm);
+    }
+  } else {
+    /* create a new arg */
+    grpc_arg tmp;
+    tmp.type = GRPC_ARG_INTEGER;
+    tmp.key = GRPC_COMPRESSION_ALGORITHM_STATE_ARG;
+    /* all enabled by default */
+    tmp.value.integer = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
+    if (state != 0) {
+      GPR_BITSET(&tmp.value.integer, algorithm);
+    } else {
+      GPR_BITCLEAR(&tmp.value.integer, algorithm);
+    }
+    result = grpc_channel_args_copy_and_add(*a, &tmp, 1);
+    grpc_channel_args_destroy(*a);
+    *a = result;
+  }
+  return result;
+}
+
+int grpc_channel_args_compression_algorithm_get_states(
+    const grpc_channel_args *a) {
+  int *states_arg;
+  if (find_compression_algorithm_states_bitset(a, &states_arg)) {
+    return *states_arg;
+  } else {
+    return (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1; /* All algs. enabled */
+  }
+}
diff --git a/src/core/channel/channel_args.h b/src/core/channel/channel_args.h
index 7e6ddd3997..06a6012dee 100644
--- a/src/core/channel/channel_args.h
+++ b/src/core/channel/channel_args.h
@@ -67,4 +67,24 @@ grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
 grpc_channel_args *grpc_channel_args_set_compression_algorithm(
     grpc_channel_args *a, grpc_compression_algorithm algorithm);
 
+/** Sets the support for the given compression algorithm. By default, all
+ * compression algorithms are enabled. It's an error to disable an algorithm set
+ * by grpc_channel_args_set_compression_algorithm.
+ *
+ * Returns an instance will the updated algorithm states. The \a a pointer is
+ * modified to point to the returned instance (which may be different from the
+ * input value of \a a). */
+grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
+    grpc_channel_args **a,
+    grpc_compression_algorithm algorithm,
+    int enabled);
+
+/** Returns the bitset representing the support state (true for enabled, false
+ * for disabled) for compression algorithms.
+ *
+ * The i-th bit of the returned bitset corresponds to the i-th entry in the
+ * grpc_compression_algorithm enum. */
+int grpc_channel_args_compression_algorithm_get_states(
+    const grpc_channel_args *a);
+
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_ARGS_H */
diff --git a/src/core/channel/client_channel.c b/src/core/channel/client_channel.c
index 6c2e6b38a8..2e25033813 100644
--- a/src/core/channel/client_channel.c
+++ b/src/core/channel/client_channel.c
@@ -84,8 +84,10 @@ typedef struct {
   grpc_pollset_set pollset_set;
 } channel_data;
 
-/** We create one watcher for each new lb_policy that is returned from a resolver,
-    to watch for state changes from the lb_policy. When a state change is seen, we
+/** We create one watcher for each new lb_policy that is returned from a
+   resolver,
+    to watch for state changes from the lb_policy. When a state change is seen,
+   we
     update the channel, and create a new watcher */
 typedef struct {
   channel_data *chand;
@@ -380,7 +382,8 @@ static void perform_transport_stream_op(grpc_call_element *elem,
           if (lb_policy) {
             grpc_transport_stream_op *op = &calld->waiting_op;
             grpc_pollset *bind_pollset = op->bind_pollset;
-            grpc_metadata_batch *initial_metadata = &op->send_ops->ops[0].data.metadata;
+            grpc_metadata_batch *initial_metadata =
+                &op->send_ops->ops[0].data.metadata;
             GRPC_LB_POLICY_REF(lb_policy, "pick");
             gpr_mu_unlock(&chand->mu_config);
             calld->state = CALL_WAITING_FOR_PICK;
@@ -388,13 +391,14 @@ static void perform_transport_stream_op(grpc_call_element *elem,
             GPR_ASSERT(op->bind_pollset);
             GPR_ASSERT(op->send_ops);
             GPR_ASSERT(op->send_ops->nops >= 1);
-            GPR_ASSERT(
-                op->send_ops->ops[0].type == GRPC_OP_METADATA);
+            GPR_ASSERT(op->send_ops->ops[0].type == GRPC_OP_METADATA);
             gpr_mu_unlock(&calld->mu_state);
 
-            grpc_iomgr_closure_init(&calld->async_setup_task, picked_target, calld);
+            grpc_iomgr_closure_init(&calld->async_setup_task, picked_target,
+                                    calld);
             grpc_lb_policy_pick(lb_policy, bind_pollset, initial_metadata,
-                                &calld->picked_channel, &calld->async_setup_task);
+                                &calld->picked_channel,
+                                &calld->async_setup_task);
 
             GRPC_LB_POLICY_UNREF(lb_policy, "pick");
           } else if (chand->resolver != NULL) {
@@ -430,7 +434,8 @@ static void cc_start_transport_stream_op(grpc_call_element *elem,
   perform_transport_stream_op(elem, op, 0);
 }
 
-static void watch_lb_policy(channel_data *chand, grpc_lb_policy *lb_policy, grpc_connectivity_state current_state);
+static void watch_lb_policy(channel_data *chand, grpc_lb_policy *lb_policy,
+                            grpc_connectivity_state current_state);
 
 static void on_lb_policy_state_changed(void *arg, int iomgr_success) {
   lb_policy_connectivity_watcher *w = arg;
@@ -450,7 +455,8 @@ static void on_lb_policy_state_changed(void *arg, int iomgr_success) {
   gpr_free(w);
 }
 
-static void watch_lb_policy(channel_data *chand, grpc_lb_policy *lb_policy, grpc_connectivity_state current_state) {
+static void watch_lb_policy(channel_data *chand, grpc_lb_policy *lb_policy,
+                            grpc_connectivity_state current_state) {
   lb_policy_connectivity_watcher *w = gpr_malloc(sizeof(*w));
   GRPC_CHANNEL_INTERNAL_REF(chand->master, "watch_lb_policy");
 
@@ -499,13 +505,13 @@ static void cc_on_config_changed(void *arg, int iomgr_success) {
   if (iomgr_success && chand->resolver) {
     grpc_resolver *resolver = chand->resolver;
     GRPC_RESOLVER_REF(resolver, "channel-next");
+    grpc_connectivity_state_set(&chand->state_tracker, state,
+                                "new_lb+resolver");
     gpr_mu_unlock(&chand->mu_config);
     GRPC_CHANNEL_INTERNAL_REF(chand->master, "resolver");
     grpc_resolver_next(resolver, &chand->incoming_configuration,
                        &chand->on_config_changed);
     GRPC_RESOLVER_UNREF(resolver, "channel-next");
-    grpc_connectivity_state_set(&chand->state_tracker, state,
-                                "new_lb+resolver");
     if (lb_policy != NULL) {
       watch_lb_policy(chand, lb_policy, state);
     }
@@ -663,7 +669,8 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
   grpc_iomgr_closure_init(&chand->on_config_changed, cc_on_config_changed,
                           chand);
 
-  grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE, "client_channel");
+  grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE,
+                               "client_channel");
 }
 
 /* Destructor for channel_data */
@@ -747,19 +754,20 @@ void grpc_client_channel_watch_connectivity_state(
   gpr_mu_unlock(&chand->mu_config);
 }
 
-grpc_pollset_set *grpc_client_channel_get_connecting_pollset_set(grpc_channel_element *elem) {
+grpc_pollset_set *grpc_client_channel_get_connecting_pollset_set(
+    grpc_channel_element *elem) {
   channel_data *chand = elem->channel_data;
   return &chand->pollset_set;
 }
 
 void grpc_client_channel_add_interested_party(grpc_channel_element *elem,
-                                          grpc_pollset *pollset) {
+                                              grpc_pollset *pollset) {
   channel_data *chand = elem->channel_data;
   grpc_pollset_set_add_pollset(&chand->pollset_set, pollset);
 }
 
 void grpc_client_channel_del_interested_party(grpc_channel_element *elem,
-                                          grpc_pollset *pollset) {
+                                              grpc_pollset *pollset) {
   channel_data *chand = elem->channel_data;
   grpc_pollset_set_del_pollset(&chand->pollset_set, pollset);
 }
diff --git a/src/core/channel/client_channel.h b/src/core/channel/client_channel.h
index cd81294eb3..13681e3956 100644
--- a/src/core/channel/client_channel.h
+++ b/src/core/channel/client_channel.h
@@ -59,11 +59,12 @@ void grpc_client_channel_watch_connectivity_state(
     grpc_channel_element *elem, grpc_connectivity_state *state,
     grpc_iomgr_closure *on_complete);
 
-grpc_pollset_set *grpc_client_channel_get_connecting_pollset_set(grpc_channel_element *elem);
+grpc_pollset_set *grpc_client_channel_get_connecting_pollset_set(
+    grpc_channel_element *elem);
 
 void grpc_client_channel_add_interested_party(grpc_channel_element *channel,
-                                          grpc_pollset *pollset);
+                                              grpc_pollset *pollset);
 void grpc_client_channel_del_interested_party(grpc_channel_element *channel,
-                                          grpc_pollset *pollset);
+                                              grpc_pollset *pollset);
 
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CLIENT_CHANNEL_H */
diff --git a/src/core/channel/compress_filter.c b/src/core/channel/compress_filter.c
index 8963c13b0f..762a4edc73 100644
--- a/src/core/channel/compress_filter.c
+++ b/src/core/channel/compress_filter.c
@@ -35,22 +35,25 @@
 #include <string.h>
 
 #include <grpc/compression.h>
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/slice_buffer.h>
 
 #include "src/core/channel/compress_filter.h"
 #include "src/core/channel/channel_args.h"
 #include "src/core/compression/message_compress.h"
+#include "src/core/support/string.h"
 
 typedef struct call_data {
   gpr_slice_buffer slices; /**< Buffers up input slices to be compressed */
   grpc_linked_mdelem compression_algorithm_storage;
+  grpc_linked_mdelem accept_encoding_storage;
   int remaining_slice_bytes; /**< Input data to be read, as per BEGIN_MESSAGE */
   int written_initial_metadata; /**< Already processed initial md? */
   /** Compression algorithm we'll try to use. It may be given by incoming
    * metadata, or by the channel's default compression settings. */
   grpc_compression_algorithm compression_algorithm;
-   /** If true, contents of \a compression_algorithm are authoritative */
+  /** If true, contents of \a compression_algorithm are authoritative */
   int has_compression_algorithm;
 } call_data;
 
@@ -59,8 +62,12 @@ typedef struct channel_data {
   grpc_mdstr *mdstr_request_compression_algorithm_key;
   /** Metadata key for the outgoing (used) compression algorithm */
   grpc_mdstr *mdstr_outgoing_compression_algorithm_key;
+  /** Metadata key for the accepted encodings */
+  grpc_mdstr *mdstr_compression_capabilities_key;
   /** Precomputed metadata elements for all available compression algorithms */
   grpc_mdelem *mdelem_compression_algorithms[GRPC_COMPRESS_ALGORITHMS_COUNT];
+  /** Precomputed metadata elements for the accepted encodings */
+  grpc_mdelem *mdelem_accept_encoding;
   /** The default, channel-level, compression algorithm */
   grpc_compression_algorithm default_compression_algorithm;
 } channel_data;
@@ -71,7 +78,7 @@ typedef struct channel_data {
  *
  * Returns 1 if the data was actually compress and 0 otherwise. */
 static int compress_send_sb(grpc_compression_algorithm algorithm,
-                             gpr_slice_buffer *slices) {
+                            gpr_slice_buffer *slices) {
   int did_compress;
   gpr_slice_buffer tmp;
   gpr_slice_buffer_init(&tmp);
@@ -86,14 +93,14 @@ static int compress_send_sb(grpc_compression_algorithm algorithm,
 /** For each \a md element from the incoming metadata, filter out the entry for
  * "grpc-encoding", using its value to populate the call data's
  * compression_algorithm field. */
-static grpc_mdelem* compression_md_filter(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *compression_md_filter(void *user_data, grpc_mdelem *md) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
 
   if (md->key == channeld->mdstr_request_compression_algorithm_key) {
     const char *md_c_str = grpc_mdstr_as_c_string(md->value);
-    if (!grpc_compression_algorithm_parse(md_c_str,
+    if (!grpc_compression_algorithm_parse(md_c_str, strlen(md_c_str),
                                           &calld->compression_algorithm)) {
       gpr_log(GPR_ERROR, "Invalid compression algorithm: '%s'. Ignoring.",
               md_c_str);
@@ -108,10 +115,10 @@ static grpc_mdelem* compression_md_filter(void *user_data, grpc_mdelem *md) {
 
 static int skip_compression(channel_data *channeld, call_data *calld) {
   if (calld->has_compression_algorithm) {
-     if (calld->compression_algorithm == GRPC_COMPRESS_NONE) {
-       return 1;
-     }
-     return 0;  /* we have an actual call-specific algorithm */
+    if (calld->compression_algorithm == GRPC_COMPRESS_NONE) {
+      return 1;
+    }
+    return 0; /* we have an actual call-specific algorithm */
   }
   /* no per-call compression override */
   return channeld->default_compression_algorithm == GRPC_COMPRESS_NONE;
@@ -184,7 +191,7 @@ static void process_send_ops(grpc_call_element *elem,
          * given by GRPC_OP_BEGIN_MESSAGE) */
         calld->remaining_slice_bytes = sop->data.begin_message.length;
         if (sop->data.begin_message.flags & GRPC_WRITE_NO_COMPRESS) {
-          calld->has_compression_algorithm = 1;  /* GPR_TRUE */
+          calld->has_compression_algorithm = 1; /* GPR_TRUE */
           calld->compression_algorithm = GRPC_COMPRESS_NONE;
         }
         break;
@@ -202,10 +209,17 @@ static void process_send_ops(grpc_call_element *elem,
                 channeld->default_compression_algorithm;
             calld->has_compression_algorithm = 1; /* GPR_TRUE */
           }
+          /* hint compression algorithm */
           grpc_metadata_batch_add_tail(
               &(sop->data.metadata), &calld->compression_algorithm_storage,
               GRPC_MDELEM_REF(channeld->mdelem_compression_algorithms
                                   [calld->compression_algorithm]));
+
+          /* convey supported compression algorithms */
+          grpc_metadata_batch_add_tail(
+              &(sop->data.metadata), &calld->accept_encoding_storage,
+              GRPC_MDELEM_REF(channeld->mdelem_accept_encoding));
+
           calld->written_initial_metadata = 1; /* GPR_TRUE */
         }
         break;
@@ -279,6 +293,9 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
                               int is_first, int is_last) {
   channel_data *channeld = elem->channel_data;
   grpc_compression_algorithm algo_idx;
+  const char *supported_algorithms_names[GRPC_COMPRESS_ALGORITHMS_COUNT - 1];
+  char *accept_encoding_str;
+  size_t accept_encoding_str_len;
 
   channeld->default_compression_algorithm =
       grpc_channel_args_get_compression_algorithm(args);
@@ -289,6 +306,9 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
   channeld->mdstr_outgoing_compression_algorithm_key =
       grpc_mdstr_from_string(mdctx, "grpc-encoding", 0);
 
+  channeld->mdstr_compression_capabilities_key =
+      grpc_mdstr_from_string(mdctx, "grpc-accept-encoding", 0);
+
   for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
     char *algorithm_name;
     GPR_ASSERT(grpc_compression_algorithm_name(algo_idx, &algorithm_name) != 0);
@@ -297,8 +317,22 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
             mdctx,
             GRPC_MDSTR_REF(channeld->mdstr_outgoing_compression_algorithm_key),
             grpc_mdstr_from_string(mdctx, algorithm_name, 0));
+    if (algo_idx > 0) {
+      supported_algorithms_names[algo_idx - 1] = algorithm_name;
+    }
   }
 
+  /* TODO(dgq): gpr_strjoin_sep could be made to work with statically allocated
+   * arrays, as to avoid the heap allocs */
+  accept_encoding_str = gpr_strjoin_sep(
+      supported_algorithms_names, GPR_ARRAY_SIZE(supported_algorithms_names),
+      ", ", &accept_encoding_str_len);
+
+  channeld->mdelem_accept_encoding = grpc_mdelem_from_metadata_strings(
+      mdctx, GRPC_MDSTR_REF(channeld->mdstr_compression_capabilities_key),
+      grpc_mdstr_from_string(mdctx, accept_encoding_str, 0));
+  gpr_free(accept_encoding_str);
+
   GPR_ASSERT(!is_last);
 }
 
@@ -309,10 +343,11 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
 
   GRPC_MDSTR_UNREF(channeld->mdstr_request_compression_algorithm_key);
   GRPC_MDSTR_UNREF(channeld->mdstr_outgoing_compression_algorithm_key);
-  for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT;
-       ++algo_idx) {
+  GRPC_MDSTR_UNREF(channeld->mdstr_compression_capabilities_key);
+  for (algo_idx = 0; algo_idx < GRPC_COMPRESS_ALGORITHMS_COUNT; ++algo_idx) {
     GRPC_MDELEM_UNREF(channeld->mdelem_compression_algorithms[algo_idx]);
   }
+  GRPC_MDELEM_UNREF(channeld->mdelem_accept_encoding);
 }
 
 const grpc_channel_filter grpc_compress_filter = {
diff --git a/src/core/channel/compress_filter.h b/src/core/channel/compress_filter.h
index 0694e2c1dd..415459bca6 100644
--- a/src/core/channel/compress_filter.h
+++ b/src/core/channel/compress_filter.h
@@ -36,7 +36,7 @@
 
 #include "src/core/channel/channel_stack.h"
 
-#define GRPC_COMPRESS_REQUEST_ALGORITHM_KEY "internal:grpc-encoding-request"
+#define GRPC_COMPRESS_REQUEST_ALGORITHM_KEY "grpc-internal-encoding-request"
 
 /** Compression filter for outgoing data.
  *
@@ -62,4 +62,4 @@
 
 extern const grpc_channel_filter grpc_compress_filter;
 
-#endif  /* GRPC_INTERNAL_CORE_CHANNEL_COMPRESS_FILTER_H */
+#endif /* GRPC_INTERNAL_CORE_CHANNEL_COMPRESS_FILTER_H */
diff --git a/src/core/channel/http_client_filter.c b/src/core/channel/http_client_filter.c
index 48c623d359..2b61d33c29 100644
--- a/src/core/channel/http_client_filter.c
+++ b/src/core/channel/http_client_filter.c
@@ -45,7 +45,6 @@ typedef struct call_data {
   grpc_linked_mdelem content_type;
   grpc_linked_mdelem user_agent;
   int sent_initial_metadata;
-  int sent_authority;
 
   int got_initial_metadata;
   grpc_stream_op_buffer *recv_ops;
@@ -64,7 +63,6 @@ typedef struct channel_data {
   grpc_mdelem *scheme;
   grpc_mdelem *content_type;
   grpc_mdelem *status;
-  grpc_mdelem *default_authority;
   /** complete user agent mdelem */
   grpc_mdelem *user_agent;
 } channel_data;
@@ -103,7 +101,6 @@ static void hc_on_recv(void *user_data, int success) {
 
 static grpc_mdelem *client_strip_filter(void *user_data, grpc_mdelem *md) {
   grpc_call_element *elem = user_data;
-  call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
   /* eat the things we'd like to set ourselves */
   if (md->key == channeld->method->key) return NULL;
@@ -111,10 +108,6 @@ static grpc_mdelem *client_strip_filter(void *user_data, grpc_mdelem *md) {
   if (md->key == channeld->te_trailers->key) return NULL;
   if (md->key == channeld->content_type->key) return NULL;
   if (md->key == channeld->user_agent->key) return NULL;
-  if (channeld->default_authority &&
-      channeld->default_authority->key == md->key) {
-    calld->sent_authority = 1;
-  }
   return md;
 }
 
@@ -138,11 +131,6 @@ static void hc_mutate_op(grpc_call_element *elem,
                                    GRPC_MDELEM_REF(channeld->method));
       grpc_metadata_batch_add_head(&op->data.metadata, &calld->scheme,
                                    GRPC_MDELEM_REF(channeld->scheme));
-      if (channeld->default_authority && !calld->sent_authority) {
-        grpc_metadata_batch_add_head(
-            &op->data.metadata, &calld->authority,
-            GRPC_MDELEM_REF(channeld->default_authority));
-      }
       grpc_metadata_batch_add_tail(&op->data.metadata, &calld->te_trailers,
                                    GRPC_MDELEM_REF(channeld->te_trailers));
       grpc_metadata_batch_add_tail(&op->data.metadata, &calld->content_type,
@@ -175,7 +163,6 @@ static void init_call_elem(grpc_call_element *elem,
   call_data *calld = elem->call_data;
   calld->sent_initial_metadata = 0;
   calld->got_initial_metadata = 0;
-  calld->sent_authority = 0;
   calld->on_done_recv = NULL;
   grpc_iomgr_closure_init(&calld->hc_on_recv, hc_on_recv, elem);
   if (initial_op) hc_mutate_op(elem, initial_op);
@@ -257,8 +244,6 @@ static grpc_mdstr *user_agent_from_args(grpc_mdctx *mdctx,
 static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
                               const grpc_channel_args *channel_args,
                               grpc_mdctx *mdctx, int is_first, int is_last) {
-  size_t i;
-
   /* grab pointers to our data from the channel element */
   channel_data *channeld = elem->channel_data;
 
@@ -267,21 +252,6 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
      path */
   GPR_ASSERT(!is_last);
 
-  channeld->default_authority = NULL;
-  if (channel_args) {
-    for (i = 0; i < channel_args->num_args; i++) {
-      if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_DEFAULT_AUTHORITY)) {
-        if (channel_args->args[i].type != GRPC_ARG_STRING) {
-          gpr_log(GPR_ERROR, "%s: must be an string",
-                  GRPC_ARG_DEFAULT_AUTHORITY);
-        } else {
-          channeld->default_authority = grpc_mdelem_from_strings(
-              mdctx, ":authority", channel_args->args[i].value.string);
-        }
-      }
-    }
-  }
-
   /* initialize members */
   channeld->te_trailers = grpc_mdelem_from_strings(mdctx, "te", "trailers");
   channeld->method = grpc_mdelem_from_strings(mdctx, ":method", "POST");
@@ -306,9 +276,6 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   GRPC_MDELEM_UNREF(channeld->content_type);
   GRPC_MDELEM_UNREF(channeld->status);
   GRPC_MDELEM_UNREF(channeld->user_agent);
-  if (channeld->default_authority) {
-    GRPC_MDELEM_UNREF(channeld->default_authority);
-  }
 }
 
 const grpc_channel_filter grpc_http_client_filter = {
diff --git a/src/core/channel/http_client_filter.h b/src/core/channel/http_client_filter.h
index 04eb839e00..21c66b9b8e 100644
--- a/src/core/channel/http_client_filter.h
+++ b/src/core/channel/http_client_filter.h
@@ -41,4 +41,4 @@ extern const grpc_channel_filter grpc_http_client_filter;
 
 #define GRPC_ARG_HTTP2_SCHEME "grpc.http2_scheme"
 
-#endif  /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_CLIENT_FILTER_H */
+#endif /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_CLIENT_FILTER_H */
diff --git a/src/core/channel/http_server_filter.h b/src/core/channel/http_server_filter.h
index 42f76ed17f..f219d4e66f 100644
--- a/src/core/channel/http_server_filter.h
+++ b/src/core/channel/http_server_filter.h
@@ -39,4 +39,4 @@
 /* Processes metadata on the client side for HTTP2 transports */
 extern const grpc_channel_filter grpc_http_server_filter;
 
-#endif  /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_SERVER_FILTER_H */
+#endif /* GRPC_INTERNAL_CORE_CHANNEL_HTTP_SERVER_FILTER_H */
diff --git a/src/core/channel/noop_filter.h b/src/core/channel/noop_filter.h
index 96463e5322..ded9b33117 100644
--- a/src/core/channel/noop_filter.h
+++ b/src/core/channel/noop_filter.h
@@ -41,4 +41,4 @@
    customize for their own filters */
 extern const grpc_channel_filter grpc_no_op_filter;
 
-#endif  /* GRPC_INTERNAL_CORE_CHANNEL_NOOP_FILTER_H */
+#endif /* GRPC_INTERNAL_CORE_CHANNEL_NOOP_FILTER_H */
diff --git a/src/core/client_config/resolver_factory.c b/src/core/client_config/resolver_factory.c
index 6721977e21..5b859a8d10 100644
--- a/src/core/client_config/resolver_factory.c
+++ b/src/core/client_config/resolver_factory.c
@@ -45,6 +45,12 @@ void grpc_resolver_factory_unref(grpc_resolver_factory *factory) {
 grpc_resolver *grpc_resolver_factory_create_resolver(
     grpc_resolver_factory *factory, grpc_uri *uri,
     grpc_subchannel_factory *subchannel_factory) {
-  if (!factory) return NULL;
+  if (factory == NULL) return NULL;
   return factory->vtable->create_resolver(factory, uri, subchannel_factory);
 }
+
+char *grpc_resolver_factory_get_default_authority(
+    grpc_resolver_factory *factory, grpc_uri *uri) {
+  if (factory == NULL) return NULL;
+  return factory->vtable->get_default_authority(factory, uri);
+}
diff --git a/src/core/client_config/resolver_factory.h b/src/core/client_config/resolver_factory.h
index c5d85499c6..e243b23988 100644
--- a/src/core/client_config/resolver_factory.h
+++ b/src/core/client_config/resolver_factory.h
@@ -51,9 +51,16 @@ struct grpc_resolver_factory_vtable {
   void (*ref)(grpc_resolver_factory *factory);
   void (*unref)(grpc_resolver_factory *factory);
 
+  /** Implementation of grpc_resolver_factory_create_resolver */
   grpc_resolver *(*create_resolver)(
       grpc_resolver_factory *factory, grpc_uri *uri,
       grpc_subchannel_factory *subchannel_factory);
+
+  /** Implementation of grpc_resolver_factory_get_default_authority */
+  char *(*get_default_authority)(grpc_resolver_factory *factory, grpc_uri *uri);
+
+  /** URI scheme that this factory implements */
+  const char *scheme;
 };
 
 void grpc_resolver_factory_ref(grpc_resolver_factory *resolver);
@@ -64,4 +71,9 @@ grpc_resolver *grpc_resolver_factory_create_resolver(
     grpc_resolver_factory *factory, grpc_uri *uri,
     grpc_subchannel_factory *subchannel_factory);
 
+/** Return a (freshly allocated with gpr_malloc) string representing
+    the default authority to use for this scheme. */
+char *grpc_resolver_factory_get_default_authority(
+    grpc_resolver_factory *factory, grpc_uri *uri);
+
 #endif /* GRPC_INTERNAL_CORE_CONFIG_RESOLVER_FACTORY_H */
diff --git a/src/core/client_config/resolver_registry.c b/src/core/client_config/resolver_registry.c
index 16be2da994..37979b3b86 100644
--- a/src/core/client_config/resolver_registry.c
+++ b/src/core/client_config/resolver_registry.c
@@ -41,41 +41,33 @@
 
 #define MAX_RESOLVERS 10
 
-typedef struct {
-  char *scheme;
-  grpc_resolver_factory *factory;
-} registered_resolver;
-
-static registered_resolver g_all_of_the_resolvers[MAX_RESOLVERS];
+static grpc_resolver_factory *g_all_of_the_resolvers[MAX_RESOLVERS];
 static int g_number_of_resolvers = 0;
 
-static char *g_default_resolver_scheme;
+static char *g_default_resolver_prefix;
 
-void grpc_resolver_registry_init(const char *default_resolver_scheme) {
+void grpc_resolver_registry_init(const char *default_resolver_prefix) {
   g_number_of_resolvers = 0;
-  g_default_resolver_scheme = gpr_strdup(default_resolver_scheme);
+  g_default_resolver_prefix = gpr_strdup(default_resolver_prefix);
 }
 
 void grpc_resolver_registry_shutdown(void) {
   int i;
   for (i = 0; i < g_number_of_resolvers; i++) {
-    gpr_free(g_all_of_the_resolvers[i].scheme);
-    grpc_resolver_factory_unref(g_all_of_the_resolvers[i].factory);
+    grpc_resolver_factory_unref(g_all_of_the_resolvers[i]);
   }
-  gpr_free(g_default_resolver_scheme);
+  gpr_free(g_default_resolver_prefix);
 }
 
-void grpc_register_resolver_type(const char *scheme,
-                                 grpc_resolver_factory *factory) {
+void grpc_register_resolver_type(grpc_resolver_factory *factory) {
   int i;
   for (i = 0; i < g_number_of_resolvers; i++) {
-    GPR_ASSERT(0 != strcmp(scheme, g_all_of_the_resolvers[i].scheme));
+    GPR_ASSERT(0 != strcmp(factory->vtable->scheme,
+                           g_all_of_the_resolvers[i]->vtable->scheme));
   }
   GPR_ASSERT(g_number_of_resolvers != MAX_RESOLVERS);
-  g_all_of_the_resolvers[g_number_of_resolvers].scheme = gpr_strdup(scheme);
   grpc_resolver_factory_ref(factory);
-  g_all_of_the_resolvers[g_number_of_resolvers].factory = factory;
-  g_number_of_resolvers++;
+  g_all_of_the_resolvers[g_number_of_resolvers++] = factory;
 }
 
 static grpc_resolver_factory *lookup_factory(grpc_uri *uri) {
@@ -85,40 +77,57 @@ static grpc_resolver_factory *lookup_factory(grpc_uri *uri) {
   if (!uri) return NULL;
 
   for (i = 0; i < g_number_of_resolvers; i++) {
-    if (0 == strcmp(uri->scheme, g_all_of_the_resolvers[i].scheme)) {
-      return g_all_of_the_resolvers[i].factory;
+    if (0 == strcmp(uri->scheme, g_all_of_the_resolvers[i]->vtable->scheme)) {
+      return g_all_of_the_resolvers[i];
     }
   }
 
   return NULL;
 }
 
-grpc_resolver *grpc_resolver_create(
-    const char *name, grpc_subchannel_factory *subchannel_factory) {
-  grpc_uri *uri;
+static grpc_resolver_factory *resolve_factory(const char *target,
+                                              grpc_uri **uri) {
   char *tmp;
   grpc_resolver_factory *factory = NULL;
-  grpc_resolver *resolver;
-
-  uri = grpc_uri_parse(name, 1);
-  factory = lookup_factory(uri);
-  if (factory == NULL && g_default_resolver_scheme != NULL) {
-    grpc_uri_destroy(uri);
-    gpr_asprintf(&tmp, "%s%s", g_default_resolver_scheme, name);
-    uri = grpc_uri_parse(tmp, 1);
-    factory = lookup_factory(uri);
-    if (factory == NULL) {
-      grpc_uri_destroy(grpc_uri_parse(name, 0));
-      grpc_uri_destroy(grpc_uri_parse(tmp, 0));
-      gpr_log(GPR_ERROR, "don't know how to resolve '%s' or '%s'", name, tmp);
+
+  GPR_ASSERT(uri != NULL);
+  *uri = grpc_uri_parse(target, 1);
+  factory = lookup_factory(*uri);
+  if (factory == NULL) {
+    if (g_default_resolver_prefix != NULL) {
+      grpc_uri_destroy(*uri);
+      gpr_asprintf(&tmp, "%s%s", g_default_resolver_prefix, target);
+      *uri = grpc_uri_parse(tmp, 1);
+      factory = lookup_factory(*uri);
+      if (factory == NULL) {
+        grpc_uri_destroy(grpc_uri_parse(target, 0));
+        grpc_uri_destroy(grpc_uri_parse(tmp, 0));
+        gpr_log(GPR_ERROR, "don't know how to resolve '%s' or '%s'", target,
+                tmp);
+      }
+      gpr_free(tmp);
+    } else {
+      grpc_uri_destroy(grpc_uri_parse(target, 0));
+      gpr_log(GPR_ERROR, "don't know how to resolve '%s'", target);
     }
-    gpr_free(tmp);
-  } else if (factory == NULL) {
-    grpc_uri_destroy(grpc_uri_parse(name, 0));
-    gpr_log(GPR_ERROR, "don't know how to resolve '%s'", name);
   }
-  resolver =
+  return factory;
+}
+
+grpc_resolver *grpc_resolver_create(
+    const char *target, grpc_subchannel_factory *subchannel_factory) {
+  grpc_uri *uri = NULL;
+  grpc_resolver_factory *factory = resolve_factory(target, &uri);
+  grpc_resolver *resolver =
       grpc_resolver_factory_create_resolver(factory, uri, subchannel_factory);
   grpc_uri_destroy(uri);
   return resolver;
 }
+
+char *grpc_get_default_authority(const char *target) {
+  grpc_uri *uri = NULL;
+  grpc_resolver_factory *factory = resolve_factory(target, &uri);
+  char *authority = grpc_resolver_factory_get_default_authority(factory, uri);
+  grpc_uri_destroy(uri);
+  return authority;
+}
diff --git a/src/core/client_config/resolver_registry.h b/src/core/client_config/resolver_registry.h
index 31aa47620a..5a7193b7ae 100644
--- a/src/core/client_config/resolver_registry.h
+++ b/src/core/client_config/resolver_registry.h
@@ -44,19 +44,22 @@ void grpc_resolver_registry_shutdown(void);
     If \a priority is greater than zero, then the resolver will be eligible
     to resolve names that are passed in with no scheme. Higher priority
     resolvers will be tried before lower priority schemes. */
-void grpc_register_resolver_type(const char *scheme,
-                                 grpc_resolver_factory *factory);
+void grpc_register_resolver_type(grpc_resolver_factory *factory);
 
-/** Create a resolver given \a name.
-    First tries to parse \a name as a URI. If this succeeds, tries
+/** Create a resolver given \a target.
+    First tries to parse \a target as a URI. If this succeeds, tries
     to locate a registered resolver factory based on the URI scheme.
     If parsing or location fails, prefixes default_prefix from
-    grpc_resolver_registry_init to name, and tries again (if default_prefix
+    grpc_resolver_registry_init to target, and tries again (if default_prefix
     was not NULL).
     If a resolver factory was found, use it to instantiate a resolver and
     return it.
     If a resolver factory was not found, return NULL. */
 grpc_resolver *grpc_resolver_create(
-    const char *name, grpc_subchannel_factory *subchannel_factory);
+    const char *target, grpc_subchannel_factory *subchannel_factory);
+
+/** Given a target, return a (freshly allocated with gpr_malloc) string
+    representing the default authority to pass from a client. */
+char *grpc_get_default_authority(const char *target);
 
 #endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVER_REGISTRY_H */
diff --git a/src/core/client_config/resolvers/dns_resolver.c b/src/core/client_config/resolvers/dns_resolver.c
index 827b1a2be5..84643c464a 100644
--- a/src/core/client_config/resolvers/dns_resolver.c
+++ b/src/core/client_config/resolvers/dns_resolver.c
@@ -203,9 +203,6 @@ static grpc_resolver *dns_create(
     grpc_subchannel_factory *subchannel_factory) {
   dns_resolver *r;
   const char *path = uri->path;
-  grpc_arg default_host_arg;
-  char *host;
-  char *port;
 
   if (0 != strcmp(uri->authority, "")) {
     gpr_log(GPR_ERROR, "authority based uri's not supported");
@@ -214,16 +211,6 @@ static grpc_resolver *dns_create(
 
   if (path[0] == '/') ++path;
 
-  gpr_split_host_port(path, &host, &port);
-
-  default_host_arg.type = GRPC_ARG_STRING;
-  default_host_arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
-  default_host_arg.value.string = host;
-  subchannel_factory = grpc_subchannel_factory_add_channel_arg(subchannel_factory, &default_host_arg);
-
-  gpr_free(host);
-  gpr_free(port);
-
   r = gpr_malloc(sizeof(dns_resolver));
   memset(r, 0, sizeof(*r));
   gpr_ref_init(&r->refs, 1);
@@ -232,6 +219,7 @@ static grpc_resolver *dns_create(
   r->name = gpr_strdup(path);
   r->default_port = gpr_strdup(default_port);
   r->subchannel_factory = subchannel_factory;
+  grpc_subchannel_factory_ref(subchannel_factory);
   r->lb_policy_factory = lb_policy_factory;
   return &r->base;
 }
@@ -251,8 +239,16 @@ static grpc_resolver *dns_factory_create_resolver(
                     subchannel_factory);
 }
 
+char *dns_factory_get_default_host_name(grpc_resolver_factory *factory,
+                                        grpc_uri *uri) {
+  const char *path = uri->path;
+  if (path[0] == '/') ++path;
+  return gpr_strdup(path);
+}
+
 static const grpc_resolver_factory_vtable dns_factory_vtable = {
-    dns_factory_ref, dns_factory_unref, dns_factory_create_resolver};
+    dns_factory_ref, dns_factory_unref, dns_factory_create_resolver,
+    dns_factory_get_default_host_name, "dns"};
 static grpc_resolver_factory dns_resolver_factory = {&dns_factory_vtable};
 
 grpc_resolver_factory *grpc_dns_resolver_factory_create() {
diff --git a/src/core/client_config/resolvers/sockaddr_resolver.c b/src/core/client_config/resolvers/sockaddr_resolver.c
index 74584e7e2c..0d8540a566 100644
--- a/src/core/client_config/resolvers/sockaddr_resolver.c
+++ b/src/core/client_config/resolvers/sockaddr_resolver.c
@@ -60,9 +60,12 @@ typedef struct {
   grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels,
                                        size_t num_subchannels);
 
-  /** the address that we've 'resolved' */
-  struct sockaddr_storage addr;
-  int addr_len;
+  /** the addresses that we've 'resolved' */
+  struct sockaddr_storage *addrs;
+  /** the corresponding length of the addresses */
+  int *addrs_len;
+  /** how many elements in \a addrs */
+  size_t num_addrs;
 
   /** mutex guarding the rest of the state */
   gpr_mu mu;
@@ -119,17 +122,22 @@ static void sockaddr_next(grpc_resolver *resolver,
 static void sockaddr_maybe_finish_next_locked(sockaddr_resolver *r) {
   grpc_client_config *cfg;
   grpc_lb_policy *lb_policy;
-  grpc_subchannel *subchannel;
+  grpc_subchannel **subchannels;
   grpc_subchannel_args args;
 
   if (r->next_completion != NULL && !r->published) {
+    size_t i;
     cfg = grpc_client_config_create();
-    memset(&args, 0, sizeof(args));
-    args.addr = (struct sockaddr *)&r->addr;
-    args.addr_len = r->addr_len;
-    subchannel =
-        grpc_subchannel_factory_create_subchannel(r->subchannel_factory, &args);
-    lb_policy = r->lb_policy_factory(&subchannel, 1);
+    subchannels = gpr_malloc(sizeof(grpc_subchannel *) * r->num_addrs);
+    for (i = 0; i < r->num_addrs; i++) {
+      memset(&args, 0, sizeof(args));
+      args.addr = (struct sockaddr *)&r->addrs[i];
+      args.addr_len = r->addrs_len[i];
+      subchannels[i] = grpc_subchannel_factory_create_subchannel(
+          r->subchannel_factory, &args);
+    }
+    lb_policy = r->lb_policy_factory(subchannels, r->num_addrs);
+    gpr_free(subchannels);
     grpc_client_config_set_lb_policy(cfg, lb_policy);
     GRPC_LB_POLICY_UNREF(lb_policy, "unix");
     r->published = 1;
@@ -143,6 +151,8 @@ static void sockaddr_destroy(grpc_resolver *gr) {
   sockaddr_resolver *r = (sockaddr_resolver *)gr;
   gpr_mu_destroy(&r->mu);
   grpc_subchannel_factory_unref(r->subchannel_factory);
+  gpr_free(r->addrs);
+  gpr_free(r->addrs_len);
   gpr_free(r);
 }
 
@@ -156,8 +166,29 @@ static int parse_unix(grpc_uri *uri, struct sockaddr_storage *addr, int *len) {
 
   return 1;
 }
+
+static char *unix_get_default_authority(grpc_resolver_factory *factory,
+                                        grpc_uri *uri) {
+  return gpr_strdup("localhost");
+}
 #endif
 
+static char *ip_get_default_authority(grpc_uri *uri) {
+  const char *path = uri->path;
+  if (path[0] == '/') ++path;
+  return gpr_strdup(path);
+}
+
+static char *ipv4_get_default_authority(grpc_resolver_factory *factory,
+                                        grpc_uri *uri) {
+  return ip_get_default_authority(uri);
+}
+
+static char *ipv6_get_default_authority(grpc_resolver_factory *factory,
+                                        grpc_uri *uri) {
+  return ip_get_default_authority(uri);
+}
+
 static int parse_ipv4(grpc_uri *uri, struct sockaddr_storage *addr, int *len) {
   const char *host_port = uri->path;
   char *host;
@@ -238,13 +269,18 @@ done:
   return result;
 }
 
+static void do_nothing(void *ignored) {}
 static grpc_resolver *sockaddr_create(
     grpc_uri *uri,
     grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels,
                                          size_t num_subchannels),
     grpc_subchannel_factory *subchannel_factory,
     int parse(grpc_uri *uri, struct sockaddr_storage *dst, int *len)) {
+  size_t i;
+  int errors_found = 0; /* GPR_FALSE */
   sockaddr_resolver *r;
+  gpr_slice path_slice;
+  gpr_slice_buffer path_parts;
 
   if (0 != strcmp(uri->authority, "")) {
     gpr_log(GPR_ERROR, "authority based uri's not supported");
@@ -253,7 +289,29 @@ static grpc_resolver *sockaddr_create(
 
   r = gpr_malloc(sizeof(sockaddr_resolver));
   memset(r, 0, sizeof(*r));
-  if (!parse(uri, &r->addr, &r->addr_len)) {
+
+  path_slice = gpr_slice_new(uri->path, strlen(uri->path), do_nothing);
+  gpr_slice_buffer_init(&path_parts);
+
+  gpr_slice_split(path_slice, ",", &path_parts);
+  r->num_addrs = path_parts.count;
+  r->addrs = gpr_malloc(sizeof(struct sockaddr_storage) * r->num_addrs);
+  r->addrs_len = gpr_malloc(sizeof(int) * r->num_addrs);
+
+  for(i = 0; i < r->num_addrs; i++) {
+    grpc_uri ith_uri = *uri;
+    char* part_str = gpr_dump_slice(path_parts.slices[i], GPR_DUMP_ASCII);
+    ith_uri.path = part_str;
+    if (!parse(&ith_uri, &r->addrs[i], &r->addrs_len[i])) {
+      errors_found = 1; /* GPR_TRUE */
+    }
+    gpr_free(part_str);
+    if (errors_found) break;
+  }
+
+  gpr_slice_buffer_destroy(&path_parts);
+  gpr_slice_unref(path_slice);
+  if (errors_found) {
     gpr_free(r);
     return NULL;
   }
@@ -276,20 +334,20 @@ static void sockaddr_factory_ref(grpc_resolver_factory *factory) {}
 
 static void sockaddr_factory_unref(grpc_resolver_factory *factory) {}
 
-#define DECL_FACTORY(name)                                            \
-  static grpc_resolver *name##_factory_create_resolver(               \
-      grpc_resolver_factory *factory, grpc_uri *uri,                  \
-      grpc_subchannel_factory *subchannel_factory) {                  \
-    return sockaddr_create(uri, grpc_create_pick_first_lb_policy,     \
-                           subchannel_factory, parse_##name);         \
-  }                                                                   \
-  static const grpc_resolver_factory_vtable name##_factory_vtable = { \
-      sockaddr_factory_ref, sockaddr_factory_unref,                   \
-      name##_factory_create_resolver};                                \
-  static grpc_resolver_factory name##_resolver_factory = {            \
-      &name##_factory_vtable};                                        \
-  grpc_resolver_factory *grpc_##name##_resolver_factory_create() {    \
-    return &name##_resolver_factory;                                  \
+#define DECL_FACTORY(name)                                                  \
+  static grpc_resolver *name##_factory_create_resolver(                     \
+      grpc_resolver_factory *factory, grpc_uri *uri,                        \
+      grpc_subchannel_factory *subchannel_factory) {                        \
+    return sockaddr_create(uri, grpc_create_pick_first_lb_policy,           \
+                           subchannel_factory, parse_##name);               \
+  }                                                                         \
+  static const grpc_resolver_factory_vtable name##_factory_vtable = {       \
+      sockaddr_factory_ref, sockaddr_factory_unref,                         \
+      name##_factory_create_resolver, name##_get_default_authority, #name}; \
+  static grpc_resolver_factory name##_resolver_factory = {                  \
+      &name##_factory_vtable};                                              \
+  grpc_resolver_factory *grpc_##name##_resolver_factory_create() {          \
+    return &name##_resolver_factory;                                        \
   }
 
 #ifdef GPR_POSIX_SOCKET
diff --git a/src/core/client_config/resolvers/zookeeper_resolver.c b/src/core/client_config/resolvers/zookeeper_resolver.c
new file mode 100644
index 0000000000..da399f9954
--- /dev/null
+++ b/src/core/client_config/resolvers/zookeeper_resolver.c
@@ -0,0 +1,506 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/client_config/resolvers/zookeeper_resolver.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include <grpc/grpc_zookeeper.h>
+#include <zookeeper/zookeeper.h>
+
+#include "src/core/client_config/lb_policies/pick_first.h"
+#include "src/core/client_config/resolver_registry.h"
+#include "src/core/iomgr/resolve_address.h"
+#include "src/core/support/string.h"
+#include "src/core/json/json.h"
+
+/** Zookeeper session expiration time in milliseconds */
+#define GRPC_ZOOKEEPER_SESSION_TIMEOUT 15000
+
+typedef struct {
+  /** base class: must be first */
+  grpc_resolver base;
+  /** refcount */
+  gpr_refcount refs;
+  /** name to resolve */
+  char *name;
+  /** subchannel factory */
+  grpc_subchannel_factory *subchannel_factory;
+  /** load balancing policy factory */
+  grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels,
+                                       size_t num_subchannels);
+
+  /** mutex guarding the rest of the state */
+  gpr_mu mu;
+  /** are we currently resolving? */
+  int resolving;
+  /** which version of resolved_config have we published? */
+  int published_version;
+  /** which version of resolved_config is current? */
+  int resolved_version;
+  /** pending next completion, or NULL */
+  grpc_iomgr_closure *next_completion;
+  /** target config address for next completion */
+  grpc_client_config **target_config;
+  /** current (fully resolved) config */
+  grpc_client_config *resolved_config;
+
+  /** zookeeper handle */
+  zhandle_t *zookeeper_handle;
+  /** zookeeper resolved addresses */
+  grpc_resolved_addresses *resolved_addrs;
+  /** total number of addresses to be resolved */
+  int resolved_total;
+  /** number of addresses resolved */
+  int resolved_num;
+} zookeeper_resolver;
+
+static void zookeeper_destroy(grpc_resolver *r);
+
+static void zookeeper_start_resolving_locked(zookeeper_resolver *r);
+static void zookeeper_maybe_finish_next_locked(zookeeper_resolver *r);
+
+static void zookeeper_shutdown(grpc_resolver *r);
+static void zookeeper_channel_saw_error(grpc_resolver *r,
+                                        struct sockaddr *failing_address,
+                                        int failing_address_len);
+static void zookeeper_next(grpc_resolver *r, grpc_client_config **target_config,
+                           grpc_iomgr_closure *on_complete);
+
+static const grpc_resolver_vtable zookeeper_resolver_vtable = {
+    zookeeper_destroy, zookeeper_shutdown, zookeeper_channel_saw_error,
+    zookeeper_next};
+
+static void zookeeper_shutdown(grpc_resolver *resolver) {
+  zookeeper_resolver *r = (zookeeper_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  if (r->next_completion != NULL) {
+    *r->target_config = NULL;
+    grpc_iomgr_add_callback(r->next_completion);
+    r->next_completion = NULL;
+  }
+  zookeeper_close(r->zookeeper_handle);
+  gpr_mu_unlock(&r->mu);
+}
+
+static void zookeeper_channel_saw_error(grpc_resolver *resolver,
+                                        struct sockaddr *sa, int len) {
+  zookeeper_resolver *r = (zookeeper_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  if (r->resolving == 0) {
+    zookeeper_start_resolving_locked(r);
+  }
+  gpr_mu_unlock(&r->mu);
+}
+
+static void zookeeper_next(grpc_resolver *resolver,
+                           grpc_client_config **target_config,
+                           grpc_iomgr_closure *on_complete) {
+  zookeeper_resolver *r = (zookeeper_resolver *)resolver;
+  gpr_mu_lock(&r->mu);
+  GPR_ASSERT(r->next_completion == NULL);
+  r->next_completion = on_complete;
+  r->target_config = target_config;
+  if (r->resolved_version == 0 && r->resolving == 0) {
+    zookeeper_start_resolving_locked(r);
+  } else {
+    zookeeper_maybe_finish_next_locked(r);
+  }
+  gpr_mu_unlock(&r->mu);
+}
+
+/** Zookeeper global watcher for connection management
+    TODO: better connection management besides logs */
+static void zookeeper_global_watcher(zhandle_t *zookeeper_handle, int type,
+                                     int state, const char *path,
+                                     void *watcher_ctx) {
+  if (type == ZOO_SESSION_EVENT) {
+    if (state == ZOO_EXPIRED_SESSION_STATE) {
+      gpr_log(GPR_ERROR, "Zookeeper session expired");
+    } else if (state == ZOO_AUTH_FAILED_STATE) {
+      gpr_log(GPR_ERROR, "Zookeeper authentication failed");
+    }
+  }
+}
+
+/** Zookeeper watcher triggered by changes to watched nodes
+    Once triggered, it tries to resolve again to get updated addresses */
+static void zookeeper_watcher(zhandle_t *zookeeper_handle, int type, int state,
+                              const char *path, void *watcher_ctx) {
+  if (watcher_ctx != NULL) {
+    zookeeper_resolver *r = (zookeeper_resolver *)watcher_ctx;
+    if (state == ZOO_CONNECTED_STATE) {
+      gpr_mu_lock(&r->mu);
+      if (r->resolving == 0) {
+        zookeeper_start_resolving_locked(r);
+      }
+      gpr_mu_unlock(&r->mu);
+    }
+  }
+}
+
+/** Callback function after getting all resolved addresses
+    Creates a subchannel for each address */
+static void zookeeper_on_resolved(void *arg,
+                                  grpc_resolved_addresses *addresses) {
+  zookeeper_resolver *r = arg;
+  grpc_client_config *config = NULL;
+  grpc_subchannel **subchannels;
+  grpc_subchannel_args args;
+  grpc_lb_policy *lb_policy;
+  size_t i;
+  if (addresses != NULL) {
+    config = grpc_client_config_create();
+    subchannels = gpr_malloc(sizeof(grpc_subchannel *) * addresses->naddrs);
+    for (i = 0; i < addresses->naddrs; i++) {
+      memset(&args, 0, sizeof(args));
+      args.addr = (struct sockaddr *)(addresses->addrs[i].addr);
+      args.addr_len = addresses->addrs[i].len;
+      subchannels[i] = grpc_subchannel_factory_create_subchannel(
+          r->subchannel_factory, &args);
+    }
+    lb_policy = r->lb_policy_factory(subchannels, addresses->naddrs);
+    grpc_client_config_set_lb_policy(config, lb_policy);
+    GRPC_LB_POLICY_UNREF(lb_policy, "construction");
+    grpc_resolved_addresses_destroy(addresses);
+    gpr_free(subchannels);
+  }
+  gpr_mu_lock(&r->mu);
+  GPR_ASSERT(r->resolving == 1);
+  r->resolving = 0;
+  if (r->resolved_config != NULL) {
+    grpc_client_config_unref(r->resolved_config);
+  }
+  r->resolved_config = config;
+  r->resolved_version++;
+  zookeeper_maybe_finish_next_locked(r);
+  gpr_mu_unlock(&r->mu);
+
+  GRPC_RESOLVER_UNREF(&r->base, "zookeeper-resolving");
+}
+
+/** Callback function for each DNS resolved address */
+static void zookeeper_dns_resolved(void *arg,
+                                   grpc_resolved_addresses *addresses) {
+  size_t i;
+  zookeeper_resolver *r = arg;
+  int resolve_done = 0;
+
+  gpr_mu_lock(&r->mu);
+  r->resolved_num++;
+  r->resolved_addrs->addrs =
+      gpr_realloc(r->resolved_addrs->addrs,
+                  sizeof(grpc_resolved_address) *
+                      (r->resolved_addrs->naddrs + addresses->naddrs));
+  for (i = 0; i < addresses->naddrs; i++) {
+    memcpy(r->resolved_addrs->addrs[i + r->resolved_addrs->naddrs].addr,
+           addresses->addrs[i].addr, addresses->addrs[i].len);
+    r->resolved_addrs->addrs[i + r->resolved_addrs->naddrs].len =
+        addresses->addrs[i].len;
+  }
+
+  r->resolved_addrs->naddrs += addresses->naddrs;
+  grpc_resolved_addresses_destroy(addresses);
+
+  /** Wait for all addresses to be resolved */
+  resolve_done = (r->resolved_num == r->resolved_total);
+  gpr_mu_unlock(&r->mu);
+  if (resolve_done) {
+    zookeeper_on_resolved(r, r->resolved_addrs);
+  }
+}
+
+/** Parses JSON format address of a zookeeper node */
+static char *zookeeper_parse_address(const char *value, int value_len) {
+  grpc_json *json;
+  grpc_json *cur;
+  const char *host;
+  const char *port;
+  char *buffer;
+  char *address = NULL;
+
+  buffer = gpr_malloc(value_len);
+  memcpy(buffer, value, value_len);
+  json = grpc_json_parse_string_with_len(buffer, value_len);
+  if (json != NULL) {
+    host = NULL;
+    port = NULL;
+    for (cur = json->child; cur != NULL; cur = cur->next) {
+      if (!strcmp(cur->key, "host")) {
+        host = cur->value;
+        if (port != NULL) {
+          break;
+        }
+      } else if (!strcmp(cur->key, "port")) {
+        port = cur->value;
+        if (host != NULL) {
+          break;
+        }
+      }
+    }
+    if (host != NULL && port != NULL) {
+      gpr_asprintf(&address, "%s:%s", host, port);
+    }
+    grpc_json_destroy(json);
+  }
+  gpr_free(buffer);
+
+  return address;
+}
+
+static void zookeeper_get_children_node_completion(int rc, const char *value,
+                                                   int value_len,
+                                                   const struct Stat *stat,
+                                                   const void *arg) {
+  char *address = NULL;
+  zookeeper_resolver *r = (zookeeper_resolver *)arg;
+  int resolve_done = 0;
+
+  if (rc != 0) {
+    gpr_log(GPR_ERROR, "Error in getting a child node of %s", r->name);
+    return;
+  }
+
+  address = zookeeper_parse_address(value, value_len);
+  if (address != NULL) {
+    /** Further resolves address by DNS */
+    grpc_resolve_address(address, NULL, zookeeper_dns_resolved, r);
+    gpr_free(address);
+  } else {
+    gpr_log(GPR_ERROR, "Error in resolving a child node of %s", r->name);
+    gpr_mu_lock(&r->mu);
+    r->resolved_total--;
+    resolve_done = (r->resolved_num == r->resolved_total);
+    gpr_mu_unlock(&r->mu);
+    if (resolve_done) {
+      zookeeper_on_resolved(r, r->resolved_addrs);
+    }
+  }
+}
+
+static void zookeeper_get_children_completion(
+    int rc, const struct String_vector *children, const void *arg) {
+  char *path;
+  int status;
+  int i;
+  zookeeper_resolver *r = (zookeeper_resolver *)arg;
+
+  if (rc != 0) {
+    gpr_log(GPR_ERROR, "Error in getting zookeeper children of %s", r->name);
+    return;
+  }
+
+  if (children->count == 0) {
+    gpr_log(GPR_ERROR, "Error in resolving zookeeper address %s", r->name);
+    return;
+  }
+
+  r->resolved_addrs = gpr_malloc(sizeof(grpc_resolved_addresses));
+  r->resolved_addrs->addrs = NULL;
+  r->resolved_addrs->naddrs = 0;
+  r->resolved_total = children->count;
+
+  /** TODO: Replace expensive heap allocation with stack
+      if we can get maximum length of zookeeper path */
+  for (i = 0; i < children->count; i++) {
+    gpr_asprintf(&path, "%s/%s", r->name, children->data[i]);
+    status = zoo_awget(r->zookeeper_handle, path, zookeeper_watcher, r,
+                       zookeeper_get_children_node_completion, r);
+    gpr_free(path);
+    if (status != 0) {
+      gpr_log(GPR_ERROR, "Error in getting zookeeper node %s", path);
+    }
+  }
+}
+
+static void zookeeper_get_node_completion(int rc, const char *value,
+                                          int value_len,
+                                          const struct Stat *stat,
+                                          const void *arg) {
+  int status;
+  char *address = NULL;
+  zookeeper_resolver *r = (zookeeper_resolver *)arg;
+  r->resolved_addrs = NULL;
+  r->resolved_total = 0;
+  r->resolved_num = 0;
+
+  if (rc != 0) {
+    gpr_log(GPR_ERROR, "Error in getting zookeeper node %s", r->name);
+    return;
+  }
+
+  /** If zookeeper node of path r->name does not have address
+      (i.e. service node), get its children */
+  address = zookeeper_parse_address(value, value_len);
+  if (address != NULL) {
+    r->resolved_addrs = gpr_malloc(sizeof(grpc_resolved_addresses));
+    r->resolved_addrs->addrs = NULL;
+    r->resolved_addrs->naddrs = 0;
+    r->resolved_total = 1;
+    /** Further resolves address by DNS */
+    grpc_resolve_address(address, NULL, zookeeper_dns_resolved, r);
+    gpr_free(address);
+    return;
+  }
+
+  status = zoo_awget_children(r->zookeeper_handle, r->name, zookeeper_watcher,
+                              r, zookeeper_get_children_completion, r);
+  if (status != 0) {
+    gpr_log(GPR_ERROR, "Error in getting zookeeper children of %s", r->name);
+  }
+}
+
+static void zookeeper_resolve_address(zookeeper_resolver *r) {
+  int status;
+  status = zoo_awget(r->zookeeper_handle, r->name, zookeeper_watcher, r,
+                     zookeeper_get_node_completion, r);
+  if (status != 0) {
+    gpr_log(GPR_ERROR, "Error in getting zookeeper node %s", r->name);
+  }
+}
+
+static void zookeeper_start_resolving_locked(zookeeper_resolver *r) {
+  GRPC_RESOLVER_REF(&r->base, "zookeeper-resolving");
+  GPR_ASSERT(r->resolving == 0);
+  r->resolving = 1;
+  zookeeper_resolve_address(r);
+}
+
+static void zookeeper_maybe_finish_next_locked(zookeeper_resolver *r) {
+  if (r->next_completion != NULL &&
+      r->resolved_version != r->published_version) {
+    *r->target_config = r->resolved_config;
+    if (r->resolved_config != NULL) {
+      grpc_client_config_ref(r->resolved_config);
+    }
+    grpc_iomgr_add_callback(r->next_completion);
+    r->next_completion = NULL;
+    r->published_version = r->resolved_version;
+  }
+}
+
+static void zookeeper_destroy(grpc_resolver *gr) {
+  zookeeper_resolver *r = (zookeeper_resolver *)gr;
+  gpr_mu_destroy(&r->mu);
+  if (r->resolved_config != NULL) {
+    grpc_client_config_unref(r->resolved_config);
+  }
+  grpc_subchannel_factory_unref(r->subchannel_factory);
+  gpr_free(r->name);
+  gpr_free(r);
+}
+
+static grpc_resolver *zookeeper_create(
+    grpc_uri *uri,
+    grpc_lb_policy *(*lb_policy_factory)(grpc_subchannel **subchannels,
+                                         size_t num_subchannels),
+    grpc_subchannel_factory *subchannel_factory) {
+  zookeeper_resolver *r;
+  size_t length;
+  char *path = uri->path;
+
+  if (0 == strcmp(uri->authority, "")) {
+    gpr_log(GPR_ERROR, "No authority specified in zookeeper uri");
+    return NULL;
+  }
+
+  /** Removes the trailing slash if exists */
+  length = strlen(path);
+  if (length > 1 && path[length - 1] == '/') {
+    path[length - 1] = 0;
+  }
+
+  r = gpr_malloc(sizeof(zookeeper_resolver));
+  memset(r, 0, sizeof(*r));
+  gpr_ref_init(&r->refs, 1);
+  gpr_mu_init(&r->mu);
+  grpc_resolver_init(&r->base, &zookeeper_resolver_vtable);
+  r->name = gpr_strdup(path);
+
+  r->subchannel_factory = subchannel_factory;
+  r->lb_policy_factory = lb_policy_factory;
+  grpc_subchannel_factory_ref(subchannel_factory);
+
+  /** Initializes zookeeper client */
+  zoo_set_debug_level(ZOO_LOG_LEVEL_WARN);
+  r->zookeeper_handle = zookeeper_init(uri->authority, zookeeper_global_watcher,
+                                       GRPC_ZOOKEEPER_SESSION_TIMEOUT, 0, 0, 0);
+  if (r->zookeeper_handle == NULL) {
+    gpr_log(GPR_ERROR, "Unable to connect to zookeeper server");
+    return NULL;
+  }
+
+  return &r->base;
+}
+
+static void zookeeper_plugin_init() {
+  grpc_register_resolver_type(grpc_zookeeper_resolver_factory_create());
+}
+
+void grpc_zookeeper_register() {
+  grpc_register_plugin(zookeeper_plugin_init, NULL);
+}
+
+/*
+ * FACTORY
+ */
+
+static void zookeeper_factory_ref(grpc_resolver_factory *factory) {}
+
+static void zookeeper_factory_unref(grpc_resolver_factory *factory) {}
+
+static char *zookeeper_factory_get_default_hostname(
+    grpc_resolver_factory *factory, grpc_uri *uri) {
+  return NULL;
+}
+
+static grpc_resolver *zookeeper_factory_create_resolver(
+    grpc_resolver_factory *factory, grpc_uri *uri,
+    grpc_subchannel_factory *subchannel_factory) {
+  return zookeeper_create(uri, grpc_create_pick_first_lb_policy,
+                          subchannel_factory);
+}
+
+static const grpc_resolver_factory_vtable zookeeper_factory_vtable = {
+    zookeeper_factory_ref, zookeeper_factory_unref,
+    zookeeper_factory_create_resolver, zookeeper_factory_get_default_hostname,
+    "zookeeper"};
+static grpc_resolver_factory zookeeper_resolver_factory = {
+    &zookeeper_factory_vtable};
+
+grpc_resolver_factory *grpc_zookeeper_resolver_factory_create() {
+  return &zookeeper_resolver_factory;
+}
diff --git a/src/core/client_config/resolvers/zookeeper_resolver.h b/src/core/client_config/resolvers/zookeeper_resolver.h
new file mode 100644
index 0000000000..a6f002dd6d
--- /dev/null
+++ b/src/core/client_config/resolvers/zookeeper_resolver.h
@@ -0,0 +1,42 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVERS_ZOOKEEPER_RESOLVER_H
+#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVERS_ZOOKEEPER_RESOLVER_H
+
+#include "src/core/client_config/resolver_factory.h"
+
+/** Create a zookeeper resolver factory */
+grpc_resolver_factory *grpc_zookeeper_resolver_factory_create(void);
+
+#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_RESOLVERS_ZOOKEEPER_RESOLVER_H */
diff --git a/src/core/client_config/subchannel.h b/src/core/client_config/subchannel.h
index d1cd33b2af..2e36c69134 100644
--- a/src/core/client_config/subchannel.h
+++ b/src/core/client_config/subchannel.h
@@ -91,8 +91,10 @@ void grpc_subchannel_notify_on_state_change(grpc_subchannel *channel,
                                             grpc_connectivity_state *state,
                                             grpc_iomgr_closure *notify);
 
+/** express interest in \a channel's activities through \a pollset. */
 void grpc_subchannel_add_interested_party(grpc_subchannel *channel,
                                           grpc_pollset *pollset);
+/** stop following \a channel's activity through \a pollset. */
 void grpc_subchannel_del_interested_party(grpc_subchannel *channel,
                                           grpc_pollset *pollset);
 
diff --git a/src/core/client_config/subchannel_factory_decorators/add_channel_arg.c b/src/core/client_config/subchannel_factory_decorators/add_channel_arg.c
index 7dc6d99ebe..585e465fa4 100644
--- a/src/core/client_config/subchannel_factory_decorators/add_channel_arg.c
+++ b/src/core/client_config/subchannel_factory_decorators/add_channel_arg.c
@@ -35,9 +35,9 @@
 #include "src/core/client_config/subchannel_factory_decorators/merge_channel_args.h"
 
 grpc_subchannel_factory *grpc_subchannel_factory_add_channel_arg(
-		grpc_subchannel_factory *input, const grpc_arg *arg) {
-	grpc_channel_args args;
-	args.num_args = 1;
-	args.args = (grpc_arg *)arg;
-	return grpc_subchannel_factory_merge_channel_args(input, &args);
+    grpc_subchannel_factory *input, const grpc_arg *arg) {
+  grpc_channel_args args;
+  args.num_args = 1;
+  args.args = (grpc_arg *)arg;
+  return grpc_subchannel_factory_merge_channel_args(input, &args);
 }
diff --git a/src/core/client_config/subchannel_factory_decorators/add_channel_arg.h b/src/core/client_config/subchannel_factory_decorators/add_channel_arg.h
index 1937623374..8457294000 100644
--- a/src/core/client_config/subchannel_factory_decorators/add_channel_arg.h
+++ b/src/core/client_config/subchannel_factory_decorators/add_channel_arg.h
@@ -40,6 +40,7 @@
     channel_args by adding a new argument; ownership of input, arg is retained
     by the caller. */
 grpc_subchannel_factory *grpc_subchannel_factory_add_channel_arg(
-		grpc_subchannel_factory *input, const grpc_arg *arg);
+    grpc_subchannel_factory *input, const grpc_arg *arg);
 
-#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_ADD_CHANNEL_ARG_H */
+#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_ADD_CHANNEL_ARG_H \
+          */
diff --git a/src/core/client_config/subchannel_factory_decorators/merge_channel_args.c b/src/core/client_config/subchannel_factory_decorators/merge_channel_args.c
index 7e028857ac..c1b5507fde 100644
--- a/src/core/client_config/subchannel_factory_decorators/merge_channel_args.c
+++ b/src/core/client_config/subchannel_factory_decorators/merge_channel_args.c
@@ -50,7 +50,7 @@ static void merge_args_factory_ref(grpc_subchannel_factory *scf) {
 static void merge_args_factory_unref(grpc_subchannel_factory *scf) {
   merge_args_factory *f = (merge_args_factory *)scf;
   if (gpr_unref(&f->refs)) {
-  	grpc_subchannel_factory_unref(f->wrapped);
+    grpc_subchannel_factory_unref(f->wrapped);
     grpc_channel_args_destroy(f->merge_args);
     gpr_free(f);
   }
@@ -73,7 +73,7 @@ static const grpc_subchannel_factory_vtable merge_args_factory_vtable = {
     merge_args_factory_create_subchannel};
 
 grpc_subchannel_factory *grpc_subchannel_factory_merge_channel_args(
-		grpc_subchannel_factory *input, const grpc_channel_args *args) {
+    grpc_subchannel_factory *input, const grpc_channel_args *args) {
   merge_args_factory *f = gpr_malloc(sizeof(*f));
   f->base.vtable = &merge_args_factory_vtable;
   gpr_ref_init(&f->refs, 1);
diff --git a/src/core/client_config/subchannel_factory_decorators/merge_channel_args.h b/src/core/client_config/subchannel_factory_decorators/merge_channel_args.h
index 73a03b752f..f4757f0650 100644
--- a/src/core/client_config/subchannel_factory_decorators/merge_channel_args.h
+++ b/src/core/client_config/subchannel_factory_decorators/merge_channel_args.h
@@ -40,6 +40,7 @@
     channel_args by adding a new argument; ownership of input, args is retained
     by the caller. */
 grpc_subchannel_factory *grpc_subchannel_factory_merge_channel_args(
-		grpc_subchannel_factory *input, const grpc_channel_args *args);
+    grpc_subchannel_factory *input, const grpc_channel_args *args);
 
-#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_MERGE_CHANNEL_ARGS_H */
+#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_FACTORY_DECORATORS_MERGE_CHANNEL_ARGS_H \
+          */
diff --git a/src/core/compression/algorithm.c b/src/core/compression/algorithm.c
index 0fd028741e..6ed6dbe93f 100644
--- a/src/core/compression/algorithm.c
+++ b/src/core/compression/algorithm.c
@@ -35,13 +35,20 @@
 #include <string.h>
 #include <grpc/compression.h>
 
-int grpc_compression_algorithm_parse(const char* name,
+int grpc_compression_algorithm_parse(const char *name, size_t name_length,
                                      grpc_compression_algorithm *algorithm) {
-  if (strcmp(name, "identity") == 0) {
+  /* we use strncmp not only because it's safer (even though in this case it
+   * doesn't matter, given that we are comparing against string literals, but
+   * because this way we needn't have "name" nil-terminated (useful for slice
+   * data, for example) */
+  if (name_length == 0) {
+    return 0;
+  }
+  if (strncmp(name, "identity", name_length) == 0) {
     *algorithm = GRPC_COMPRESS_NONE;
-  } else if (strcmp(name, "gzip") == 0) {
+  } else if (strncmp(name, "gzip", name_length) == 0) {
     *algorithm = GRPC_COMPRESS_GZIP;
-  } else if (strcmp(name, "deflate") == 0) {
+  } else if (strncmp(name, "deflate", name_length) == 0) {
     *algorithm = GRPC_COMPRESS_DEFLATE;
   } else {
     return 0;
diff --git a/src/core/debug/trace.c b/src/core/debug/trace.c
index b53dfe804b..1014b1f4db 100644
--- a/src/core/debug/trace.c
+++ b/src/core/debug/trace.c
@@ -61,8 +61,8 @@ static void add(const char *beg, const char *end, char ***ss, size_t *ns) {
   size_t np = n + 1;
   char *s = gpr_malloc(end - beg + 1);
   memcpy(s, beg, end - beg);
-  s[end-beg] = 0;
-  *ss = gpr_realloc(*ss, sizeof(char**) * np);
+  s[end - beg] = 0;
+  *ss = gpr_realloc(*ss, sizeof(char **) * np);
   (*ss)[n] = s;
   *ns = np;
 }
@@ -73,7 +73,7 @@ static void split(const char *s, char ***ss, size_t *ns) {
     add(s, s + strlen(s), ss, ns);
   } else {
     add(s, c, ss, ns);
-    split(c+1, ss, ns);
+    split(c + 1, ss, ns);
   }
 }
 
@@ -125,7 +125,7 @@ int grpc_tracer_set_enabled(const char *name, int enabled) {
     }
     if (!found) {
       gpr_log(GPR_ERROR, "Unknown trace var: '%s'", name);
-      return 0;  /* early return */
+      return 0; /* early return */
     }
   }
   return 1;
diff --git a/src/core/debug/trace.h b/src/core/debug/trace.h
index fc8615bc69..dc5875976e 100644
--- a/src/core/debug/trace.h
+++ b/src/core/debug/trace.h
@@ -40,4 +40,4 @@ void grpc_register_tracer(const char *name, int *flag);
 void grpc_tracer_init(const char *env_var_name);
 void grpc_tracer_shutdown(void);
 
-#endif  /* GRPC_INTERNAL_CORE_DEBUG_TRACE_H */
+#endif /* GRPC_INTERNAL_CORE_DEBUG_TRACE_H */
diff --git a/src/core/httpcli/format_request.c b/src/core/httpcli/format_request.c
index e875423e87..6189fce86b 100644
--- a/src/core/httpcli/format_request.c
+++ b/src/core/httpcli/format_request.c
@@ -43,7 +43,8 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
-static void fill_common_header(const grpc_httpcli_request *request, gpr_strvec *buf) {
+static void fill_common_header(const grpc_httpcli_request *request,
+                               gpr_strvec *buf) {
   size_t i;
   gpr_strvec_add(buf, gpr_strdup(request->path));
   gpr_strvec_add(buf, gpr_strdup(" HTTP/1.0\r\n"));
@@ -52,7 +53,8 @@ static void fill_common_header(const grpc_httpcli_request *request, gpr_strvec *
   gpr_strvec_add(buf, gpr_strdup(request->host));
   gpr_strvec_add(buf, gpr_strdup("\r\n"));
   gpr_strvec_add(buf, gpr_strdup("Connection: close\r\n"));
-  gpr_strvec_add(buf, gpr_strdup("User-Agent: "GRPC_HTTPCLI_USER_AGENT"\r\n"));
+  gpr_strvec_add(buf,
+                 gpr_strdup("User-Agent: " GRPC_HTTPCLI_USER_AGENT "\r\n"));
   /* user supplied headers */
   for (i = 0; i < request->hdr_count; i++) {
     gpr_strvec_add(buf, gpr_strdup(request->hdrs[i].key));
diff --git a/src/core/httpcli/format_request.h b/src/core/httpcli/format_request.h
index 8bfb20bfd0..c8dc8f7d4e 100644
--- a/src/core/httpcli/format_request.h
+++ b/src/core/httpcli/format_request.h
@@ -42,4 +42,4 @@ gpr_slice grpc_httpcli_format_post_request(const grpc_httpcli_request *request,
                                            const char *body_bytes,
                                            size_t body_size);
 
-#endif  /* GRPC_INTERNAL_CORE_HTTPCLI_FORMAT_REQUEST_H */
+#endif /* GRPC_INTERNAL_CORE_HTTPCLI_FORMAT_REQUEST_H */
diff --git a/src/core/httpcli/parser.h b/src/core/httpcli/parser.h
index 71280e7479..3fbb4c7479 100644
--- a/src/core/httpcli/parser.h
+++ b/src/core/httpcli/parser.h
@@ -61,4 +61,4 @@ void grpc_httpcli_parser_destroy(grpc_httpcli_parser *parser);
 int grpc_httpcli_parser_parse(grpc_httpcli_parser *parser, gpr_slice slice);
 int grpc_httpcli_parser_eof(grpc_httpcli_parser *parser);
 
-#endif  /* GRPC_INTERNAL_CORE_HTTPCLI_PARSER_H */
+#endif /* GRPC_INTERNAL_CORE_HTTPCLI_PARSER_H */
diff --git a/src/core/iomgr/alarm.c b/src/core/iomgr/alarm.c
index 68d33b9cf6..ddb30dc4bb 100644
--- a/src/core/iomgr/alarm.c
+++ b/src/core/iomgr/alarm.c
@@ -105,8 +105,7 @@ void grpc_alarm_list_init(gpr_timespec now) {
 
 void grpc_alarm_list_shutdown(void) {
   int i;
-  while (run_some_expired_alarms(NULL, gpr_inf_future(g_clock_type), NULL,
-                                 0))
+  while (run_some_expired_alarms(NULL, gpr_inf_future(g_clock_type), NULL, 0))
     ;
   for (i = 0; i < NUM_SHARDS; i++) {
     shard_type *shard = &g_shards[i];
@@ -362,7 +361,7 @@ static int run_some_expired_alarms(gpr_mu *drop_mu, gpr_timespec now,
 int grpc_alarm_check(gpr_mu *drop_mu, gpr_timespec now, gpr_timespec *next) {
   GPR_ASSERT(now.clock_type == g_clock_type);
   return run_some_expired_alarms(
-      drop_mu, now, next, 
+      drop_mu, now, next,
       gpr_time_cmp(now, gpr_inf_future(now.clock_type)) != 0);
 }
 
diff --git a/src/core/iomgr/alarm.h b/src/core/iomgr/alarm.h
index c067a0b8a3..4a13527e64 100644
--- a/src/core/iomgr/alarm.h
+++ b/src/core/iomgr/alarm.h
@@ -86,4 +86,4 @@ void grpc_alarm_init(grpc_alarm *alarm, gpr_timespec deadline,
    Requires:  cancel() must happen after add() on a given alarm */
 void grpc_alarm_cancel(grpc_alarm *alarm);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_ALARM_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_ALARM_H */
diff --git a/src/core/iomgr/alarm_heap.c b/src/core/iomgr/alarm_heap.c
index d912178fda..daed251982 100644
--- a/src/core/iomgr/alarm_heap.c
+++ b/src/core/iomgr/alarm_heap.c
@@ -66,11 +66,11 @@ static void adjust_downwards(grpc_alarm **first, int i, int length,
     int next_i;
     if (left_child >= length) break;
     right_child = left_child + 1;
-    next_i =
-        right_child < length && gpr_time_cmp(first[left_child]->deadline,
-                                             first[right_child]->deadline) < 0
-            ? right_child
-            : left_child;
+    next_i = right_child < length &&
+                     gpr_time_cmp(first[left_child]->deadline,
+                                  first[right_child]->deadline) < 0
+                 ? right_child
+                 : left_child;
     if (gpr_time_cmp(t->deadline, first[next_i]->deadline) >= 0) break;
     first[i] = first[next_i];
     first[i]->heap_index = i;
diff --git a/src/core/iomgr/alarm_heap.h b/src/core/iomgr/alarm_heap.h
index c5adfc6d31..60db6c991b 100644
--- a/src/core/iomgr/alarm_heap.h
+++ b/src/core/iomgr/alarm_heap.h
@@ -54,4 +54,4 @@ void grpc_alarm_heap_pop(grpc_alarm_heap *heap);
 
 int grpc_alarm_heap_is_empty(grpc_alarm_heap *heap);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_ALARM_HEAP_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_ALARM_HEAP_H */
diff --git a/src/core/iomgr/alarm_internal.h b/src/core/iomgr/alarm_internal.h
index 0268a01bad..e9f98a3444 100644
--- a/src/core/iomgr/alarm_internal.h
+++ b/src/core/iomgr/alarm_internal.h
@@ -59,4 +59,4 @@ gpr_timespec grpc_alarm_list_next_timeout(void);
 
 void grpc_kick_poller(void);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_ALARM_INTERNAL_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_ALARM_INTERNAL_H */
diff --git a/src/core/iomgr/endpoint.c b/src/core/iomgr/endpoint.c
index 744fe7656c..8ee14bce9b 100644
--- a/src/core/iomgr/endpoint.c
+++ b/src/core/iomgr/endpoint.c
@@ -50,7 +50,8 @@ void grpc_endpoint_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset) {
   ep->vtable->add_to_pollset(ep, pollset);
 }
 
-void grpc_endpoint_add_to_pollset_set(grpc_endpoint *ep, grpc_pollset_set *pollset_set) {
+void grpc_endpoint_add_to_pollset_set(grpc_endpoint *ep,
+                                      grpc_pollset_set *pollset_set) {
   ep->vtable->add_to_pollset_set(ep, pollset_set);
 }
 
diff --git a/src/core/iomgr/endpoint.h b/src/core/iomgr/endpoint.h
index a2216925f9..ea92a500e8 100644
--- a/src/core/iomgr/endpoint.h
+++ b/src/core/iomgr/endpoint.h
@@ -103,10 +103,11 @@ void grpc_endpoint_destroy(grpc_endpoint *ep);
 /* Add an endpoint to a pollset, so that when the pollset is polled, events from
    this endpoint are considered */
 void grpc_endpoint_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset);
-void grpc_endpoint_add_to_pollset_set(grpc_endpoint *ep, grpc_pollset_set *pollset_set);
+void grpc_endpoint_add_to_pollset_set(grpc_endpoint *ep,
+                                      grpc_pollset_set *pollset_set);
 
 struct grpc_endpoint {
   const grpc_endpoint_vtable *vtable;
 };
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_H */
diff --git a/src/core/iomgr/endpoint_pair.h b/src/core/iomgr/endpoint_pair.h
index 25087be0c7..095ec5fcc9 100644
--- a/src/core/iomgr/endpoint_pair.h
+++ b/src/core/iomgr/endpoint_pair.h
@@ -44,4 +44,4 @@ typedef struct {
 grpc_endpoint_pair grpc_iomgr_create_endpoint_pair(const char *name,
                                                    size_t read_slice_size);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_PAIR_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_ENDPOINT_PAIR_H */
diff --git a/src/core/iomgr/endpoint_pair_windows.c b/src/core/iomgr/endpoint_pair_windows.c
index e8295df8b3..db9d092dca 100644
--- a/src/core/iomgr/endpoint_pair_windows.c
+++ b/src/core/iomgr/endpoint_pair_windows.c
@@ -52,21 +52,26 @@ static void create_sockets(SOCKET sv[2]) {
   SOCKADDR_IN addr;
   int addr_len = sizeof(addr);
 
-  lst_sock = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
+  lst_sock = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0,
+                       WSA_FLAG_OVERLAPPED);
   GPR_ASSERT(lst_sock != INVALID_SOCKET);
 
   memset(&addr, 0, sizeof(addr));
   addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
   addr.sin_family = AF_INET;
-  GPR_ASSERT(bind(lst_sock, (struct sockaddr*)&addr, sizeof(addr)) != SOCKET_ERROR);
+  GPR_ASSERT(bind(lst_sock, (struct sockaddr *)&addr, sizeof(addr)) !=
+             SOCKET_ERROR);
   GPR_ASSERT(listen(lst_sock, SOMAXCONN) != SOCKET_ERROR);
-  GPR_ASSERT(getsockname(lst_sock, (struct sockaddr*)&addr, &addr_len) != SOCKET_ERROR);
+  GPR_ASSERT(getsockname(lst_sock, (struct sockaddr *)&addr, &addr_len) !=
+             SOCKET_ERROR);
 
-  cli_sock = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);
+  cli_sock = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0,
+                       WSA_FLAG_OVERLAPPED);
   GPR_ASSERT(cli_sock != INVALID_SOCKET);
 
-  GPR_ASSERT(WSAConnect(cli_sock, (struct sockaddr*)&addr, addr_len, NULL, NULL, NULL, NULL) == 0);
-  svr_sock = accept(lst_sock, (struct sockaddr*)&addr, &addr_len);
+  GPR_ASSERT(WSAConnect(cli_sock, (struct sockaddr *)&addr, addr_len, NULL,
+                        NULL, NULL, NULL) == 0);
+  svr_sock = accept(lst_sock, (struct sockaddr *)&addr, &addr_len);
   GPR_ASSERT(svr_sock != INVALID_SOCKET);
 
   closesocket(lst_sock);
@@ -77,7 +82,8 @@ static void create_sockets(SOCKET sv[2]) {
   sv[0] = svr_sock;
 }
 
-grpc_endpoint_pair grpc_iomgr_create_endpoint_pair(const char *name, size_t read_slice_size) {
+grpc_endpoint_pair grpc_iomgr_create_endpoint_pair(const char *name,
+                                                   size_t read_slice_size) {
   SOCKET sv[2];
   grpc_endpoint_pair p;
   create_sockets(sv);
diff --git a/src/core/iomgr/iocp_windows.c b/src/core/iomgr/iocp_windows.c
index 8741241fb8..09a457dd9a 100644
--- a/src/core/iomgr/iocp_windows.c
+++ b/src/core/iomgr/iocp_windows.c
@@ -65,18 +65,17 @@ static void do_iocp_work() {
   LPOVERLAPPED overlapped;
   grpc_winsocket *socket;
   grpc_winsocket_callback_info *info;
-  void(*f)(void *, int) = NULL;
+  void (*f)(void *, int) = NULL;
   void *opaque = NULL;
-  success = GetQueuedCompletionStatus(g_iocp, &bytes,
-                                      &completion_key, &overlapped,
-                                      INFINITE);
+  success = GetQueuedCompletionStatus(g_iocp, &bytes, &completion_key,
+                                      &overlapped, INFINITE);
   /* success = 0 and overlapped = NULL means the deadline got attained.
      Which is impossible. since our wait time is +inf */
   GPR_ASSERT(success || overlapped);
   GPR_ASSERT(completion_key && overlapped);
   if (overlapped == &g_iocp_custom_overlap) {
     gpr_atm_full_fetch_add(&g_custom_events, -1);
-    if (completion_key == (ULONG_PTR) &g_iocp_kick_token) {
+    if (completion_key == (ULONG_PTR)&g_iocp_kick_token) {
       /* We were awoken from a kick. */
       return;
     }
@@ -84,7 +83,7 @@ static void do_iocp_work() {
     abort();
   }
 
-  socket = (grpc_winsocket*) completion_key;
+  socket = (grpc_winsocket *)completion_key;
   if (overlapped == &socket->write_info.overlapped) {
     info = &socket->write_info;
   } else if (overlapped == &socket->read_info.overlapped) {
@@ -121,8 +120,7 @@ static void do_iocp_work() {
 }
 
 static void iocp_loop(void *p) {
-  while (gpr_atm_acq_load(&g_orphans) ||
-         gpr_atm_acq_load(&g_custom_events) ||
+  while (gpr_atm_acq_load(&g_orphans) || gpr_atm_acq_load(&g_custom_events) ||
          !gpr_event_get(&g_shutdown_iocp)) {
     grpc_maybe_call_delayed_callbacks(NULL, 1);
     do_iocp_work();
@@ -134,8 +132,8 @@ static void iocp_loop(void *p) {
 void grpc_iocp_init(void) {
   gpr_thd_id id;
 
-  g_iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE,
-                                  NULL, (ULONG_PTR)NULL, 0);
+  g_iocp =
+      CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, (ULONG_PTR)NULL, 0);
   GPR_ASSERT(g_iocp);
 
   gpr_event_init(&g_iocp_done);
@@ -147,8 +145,7 @@ void grpc_iocp_kick(void) {
   BOOL success;
 
   gpr_atm_full_fetch_add(&g_custom_events, 1);
-  success = PostQueuedCompletionStatus(g_iocp, 0,
-                                       (ULONG_PTR) &g_iocp_kick_token,
+  success = PostQueuedCompletionStatus(g_iocp, 0, (ULONG_PTR)&g_iocp_kick_token,
                                        &g_iocp_custom_overlap);
   GPR_ASSERT(success);
 }
@@ -165,8 +162,8 @@ void grpc_iocp_shutdown(void) {
 void grpc_iocp_add_socket(grpc_winsocket *socket) {
   HANDLE ret;
   if (socket->added_to_iocp) return;
-  ret = CreateIoCompletionPort((HANDLE)socket->socket,
-                               g_iocp, (gpr_uintptr) socket, 0);
+  ret = CreateIoCompletionPort((HANDLE)socket->socket, g_iocp,
+                               (gpr_uintptr)socket, 0);
   if (!ret) {
     char *utf8_message = gpr_format_message(WSAGetLastError());
     gpr_log(GPR_ERROR, "Unable to add socket to iocp: %s", utf8_message);
@@ -189,7 +186,7 @@ void grpc_iocp_socket_orphan(grpc_winsocket *socket) {
    the callback now.
    -) The IOCP hasn't completed yet, and we're queuing it for later. */
 static void socket_notify_on_iocp(grpc_winsocket *socket,
-                                  void(*cb)(void *, int), void *opaque,
+                                  void (*cb)(void *, int), void *opaque,
                                   grpc_winsocket_callback_info *info) {
   int run_now = 0;
   GPR_ASSERT(!info->cb);
@@ -206,13 +203,13 @@ static void socket_notify_on_iocp(grpc_winsocket *socket,
 }
 
 void grpc_socket_notify_on_write(grpc_winsocket *socket,
-                                 void(*cb)(void *, int), void *opaque) {
+                                 void (*cb)(void *, int), void *opaque) {
   socket_notify_on_iocp(socket, cb, opaque, &socket->write_info);
 }
 
-void grpc_socket_notify_on_read(grpc_winsocket *socket,
-                                void(*cb)(void *, int), void *opaque) {
+void grpc_socket_notify_on_read(grpc_winsocket *socket, void (*cb)(void *, int),
+                                void *opaque) {
   socket_notify_on_iocp(socket, cb, opaque, &socket->read_info);
 }
 
-#endif  /* GPR_WINSOCK_SOCKET */
+#endif /* GPR_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/iocp_windows.h b/src/core/iomgr/iocp_windows.h
index 9df6476917..ee3847a229 100644
--- a/src/core/iomgr/iocp_windows.h
+++ b/src/core/iomgr/iocp_windows.h
@@ -44,10 +44,10 @@ void grpc_iocp_shutdown(void);
 void grpc_iocp_add_socket(grpc_winsocket *);
 void grpc_iocp_socket_orphan(grpc_winsocket *);
 
-void grpc_socket_notify_on_write(grpc_winsocket *, void(*cb)(void *, int success),
-                                 void *opaque);
+void grpc_socket_notify_on_write(grpc_winsocket *,
+                                 void (*cb)(void *, int success), void *opaque);
 
-void grpc_socket_notify_on_read(grpc_winsocket *, void(*cb)(void *, int success),
-                                void *opaque);
+void grpc_socket_notify_on_read(grpc_winsocket *,
+                                void (*cb)(void *, int success), void *opaque);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOCP_WINDOWS_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_IOCP_WINDOWS_H */
diff --git a/src/core/iomgr/iomgr.h b/src/core/iomgr/iomgr.h
index 6d4a82917b..261c17366a 100644
--- a/src/core/iomgr/iomgr.h
+++ b/src/core/iomgr/iomgr.h
@@ -77,4 +77,4 @@ void grpc_iomgr_add_callback(grpc_iomgr_closure *closure);
     argument. */
 void grpc_iomgr_add_delayed_callback(grpc_iomgr_closure *iocb, int success);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_H */
diff --git a/src/core/iomgr/iomgr_internal.h b/src/core/iomgr/iomgr_internal.h
index 6c1e0e1799..4cec973ba0 100644
--- a/src/core/iomgr/iomgr_internal.h
+++ b/src/core/iomgr/iomgr_internal.h
@@ -52,4 +52,4 @@ void grpc_iomgr_unregister_object(grpc_iomgr_object *obj);
 void grpc_iomgr_platform_init(void);
 void grpc_iomgr_platform_shutdown(void);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_INTERNAL_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_INTERNAL_H */
diff --git a/src/core/iomgr/iomgr_posix.c b/src/core/iomgr/iomgr_posix.c
index 758ae77b86..2425e59941 100644
--- a/src/core/iomgr/iomgr_posix.c
+++ b/src/core/iomgr/iomgr_posix.c
@@ -51,4 +51,4 @@ void grpc_iomgr_platform_shutdown(void) {
   grpc_fd_global_shutdown();
 }
 
-#endif  /* GRPC_POSIX_SOCKET */
+#endif /* GRPC_POSIX_SOCKET */
diff --git a/src/core/iomgr/iomgr_posix.h b/src/core/iomgr/iomgr_posix.h
index a404f6433e..716fedb636 100644
--- a/src/core/iomgr/iomgr_posix.h
+++ b/src/core/iomgr/iomgr_posix.h
@@ -39,4 +39,4 @@
 void grpc_pollset_global_init(void);
 void grpc_pollset_global_shutdown(void);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_POSIX_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_POSIX_H */
diff --git a/src/core/iomgr/iomgr_windows.c b/src/core/iomgr/iomgr_windows.c
index 74cd5a829b..b49cb87e97 100644
--- a/src/core/iomgr/iomgr_windows.c
+++ b/src/core/iomgr/iomgr_windows.c
@@ -68,4 +68,4 @@ void grpc_iomgr_platform_shutdown(void) {
   winsock_shutdown();
 }
 
-#endif  /* GRPC_WINSOCK_SOCKET */
+#endif /* GRPC_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/pollset.h b/src/core/iomgr/pollset.h
index c474e4dbf1..337596cb74 100644
--- a/src/core/iomgr/pollset.h
+++ b/src/core/iomgr/pollset.h
@@ -74,10 +74,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset);
    grpc_pollset_work, and it is guaranteed that GRPC_POLLSET_MU(pollset) will
    not be released by grpc_pollset_work AFTER worker has been destroyed.
 
-   Returns true if some work has been done, and false if the deadline
-   expired. */
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline);
+   Tries not to block past deadline. */
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline);
 
 /* Break one polling thread out of polling work for this pollset.
    If specific_worker is GRPC_POLLSET_KICK_BROADCAST, kick ALL the workers.
diff --git a/src/core/iomgr/pollset_multipoller_with_epoll.c b/src/core/iomgr/pollset_multipoller_with_epoll.c
index 1320c64579..fe66ebed77 100644
--- a/src/core/iomgr/pollset_multipoller_with_epoll.c
+++ b/src/core/iomgr/pollset_multipoller_with_epoll.c
@@ -181,7 +181,7 @@ static void multipoll_with_epoll_pollset_maybe_work(
   pfds[1].events = POLLIN;
   pfds[1].revents = 0;
 
-  poll_rv = poll(pfds, 2, timeout_ms);
+  poll_rv = grpc_poll_function(pfds, 2, timeout_ms);
 
   if (poll_rv < 0) {
     if (errno != EINTR) {
@@ -234,8 +234,7 @@ static void multipoll_with_epoll_pollset_destroy(grpc_pollset *pollset) {
 }
 
 static const grpc_pollset_vtable multipoll_with_epoll_pollset = {
-    multipoll_with_epoll_pollset_add_fd,
-    multipoll_with_epoll_pollset_del_fd,
+    multipoll_with_epoll_pollset_add_fd, multipoll_with_epoll_pollset_del_fd,
     multipoll_with_epoll_pollset_maybe_work,
     multipoll_with_epoll_pollset_finish_shutdown,
     multipoll_with_epoll_pollset_destroy};
diff --git a/src/core/iomgr/pollset_multipoller_with_poll_posix.c b/src/core/iomgr/pollset_multipoller_with_poll_posix.c
index b5b2d7534d..30ee6e24db 100644
--- a/src/core/iomgr/pollset_multipoller_with_poll_posix.c
+++ b/src/core/iomgr/pollset_multipoller_with_poll_posix.c
@@ -74,7 +74,7 @@ static void multipoll_with_poll_pollset_add_fd(grpc_pollset *pollset,
   }
   h->fds[h->fd_count++] = fd;
   GRPC_FD_REF(fd, "multipoller");
-exit:  
+exit:
   if (and_unlock_pollset) {
     gpr_mu_unlock(&pollset->mu);
   }
@@ -144,7 +144,7 @@ static void multipoll_with_poll_pollset_maybe_work(
                                         POLLOUT, &watchers[i]);
   }
 
-  r = poll(pfds, pfd_count, timeout);
+  r = grpc_poll_function(pfds, pfd_count, timeout);
 
   for (i = 1; i < pfd_count; i++) {
     grpc_fd_end_poll(&watchers[i], pfds[i].revents & POLLIN,
@@ -202,8 +202,7 @@ static void multipoll_with_poll_pollset_destroy(grpc_pollset *pollset) {
 }
 
 static const grpc_pollset_vtable multipoll_with_poll_pollset = {
-    multipoll_with_poll_pollset_add_fd,
-    multipoll_with_poll_pollset_del_fd,
+    multipoll_with_poll_pollset_add_fd, multipoll_with_poll_pollset_del_fd,
     multipoll_with_poll_pollset_maybe_work,
     multipoll_with_poll_pollset_finish_shutdown,
     multipoll_with_poll_pollset_destroy};
diff --git a/src/core/iomgr/pollset_posix.c b/src/core/iomgr/pollset_posix.c
index d3a9193af1..6bd1b61f24 100644
--- a/src/core/iomgr/pollset_posix.c
+++ b/src/core/iomgr/pollset_posix.c
@@ -38,7 +38,6 @@
 #include "src/core/iomgr/pollset_posix.h"
 
 #include <errno.h>
-#include <poll.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -57,6 +56,8 @@
 GPR_TLS_DECL(g_current_thread_poller);
 GPR_TLS_DECL(g_current_thread_worker);
 
+grpc_poll_function_type grpc_poll_function = poll;
+
 static void remove_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
   worker->prev->next = worker->next;
   worker->next->prev = worker->prev;
@@ -89,6 +90,7 @@ static void push_front_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {
+  /* pollset->mu already held */
   if (specific_worker != NULL) {
     if (specific_worker == GRPC_POLLSET_KICK_BROADCAST) {
       for (specific_worker = p->root_worker.next;
@@ -140,10 +142,10 @@ void grpc_pollset_init(grpc_pollset *pollset) {
 void grpc_pollset_add_fd(grpc_pollset *pollset, grpc_fd *fd) {
   gpr_mu_lock(&pollset->mu);
   pollset->vtable->add_fd(pollset, fd, 1);
-  /* the following (enabled only in debug) will reacquire and then release
-     our lock - meaning that if the unlocking flag passed to del_fd above is
-     not respected, the code will deadlock (in a way that we have a chance of
-     debugging) */
+/* the following (enabled only in debug) will reacquire and then release
+   our lock - meaning that if the unlocking flag passed to del_fd above is
+   not respected, the code will deadlock (in a way that we have a chance of
+   debugging) */
 #ifndef NDEBUG
   gpr_mu_lock(&pollset->mu);
   gpr_mu_unlock(&pollset->mu);
@@ -153,10 +155,10 @@ void grpc_pollset_add_fd(grpc_pollset *pollset, grpc_fd *fd) {
 void grpc_pollset_del_fd(grpc_pollset *pollset, grpc_fd *fd) {
   gpr_mu_lock(&pollset->mu);
   pollset->vtable->del_fd(pollset, fd, 1);
-  /* the following (enabled only in debug) will reacquire and then release
-     our lock - meaning that if the unlocking flag passed to del_fd above is
-     not respected, the code will deadlock (in a way that we have a chance of
-     debugging) */
+/* the following (enabled only in debug) will reacquire and then release
+   our lock - meaning that if the unlocking flag passed to del_fd above is
+   not respected, the code will deadlock (in a way that we have a chance of
+   debugging) */
 #ifndef NDEBUG
   gpr_mu_lock(&pollset->mu);
   gpr_mu_unlock(&pollset->mu);
@@ -168,14 +170,10 @@ static void finish_shutdown(grpc_pollset *pollset) {
   pollset->shutdown_done_cb(pollset->shutdown_done_arg);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline) {
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline) {
   /* pollset->mu already held */
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   int added_worker = 0;
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0;
-  }
   /* this must happen before we (potentially) drop pollset->mu */
   worker->next = worker->prev = NULL;
   /* TODO(ctiller): pool these */
@@ -217,7 +215,6 @@ done:
       gpr_mu_lock(&pollset->mu);
     }
   }
-  return 1;
 }
 
 void grpc_pollset_shutdown(grpc_pollset *pollset,
@@ -456,7 +453,7 @@ static void basic_pollset_maybe_work(grpc_pollset *pollset,
 
   /* poll fd count (argument 2) is shortened by one if we have no events
      to poll on - such that it only includes the kicker */
-  r = poll(pfd, nfds, timeout);
+  r = grpc_poll_function(pfd, nfds, timeout);
   GRPC_TIMER_MARK(GRPC_PTAG_POLL_FINISHED, r);
 
   if (fd) {
diff --git a/src/core/iomgr/pollset_posix.h b/src/core/iomgr/pollset_posix.h
index 1c1b736193..69bd9cca8c 100644
--- a/src/core/iomgr/pollset_posix.h
+++ b/src/core/iomgr/pollset_posix.h
@@ -34,6 +34,8 @@
 #ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 #define GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 
+#include <poll.h>
+
 #include <grpc/support/sync.h>
 #include "src/core/iomgr/wakeup_fd_posix.h"
 
@@ -102,7 +104,8 @@ void grpc_kick_drain(grpc_pollset *p);
    - longer than a millisecond polls are rounded up to the next nearest
      millisecond to avoid spinning
    - infinite timeouts are converted to -1 */
-int grpc_poll_deadline_to_millis_timeout(gpr_timespec deadline, gpr_timespec now);
+int grpc_poll_deadline_to_millis_timeout(gpr_timespec deadline,
+                                         gpr_timespec now);
 
 /* turn a pollset into a multipoller: platform specific */
 typedef void (*grpc_platform_become_multipoller_type)(grpc_pollset *pollset,
@@ -117,4 +120,8 @@ void grpc_poll_become_multipoller(grpc_pollset *pollset, struct grpc_fd **fds,
  * be locked) */
 int grpc_pollset_has_workers(grpc_pollset *pollset);
 
+/* override to allow tests to hook poll() usage */
+typedef int (*grpc_poll_function_type)(struct pollfd *, nfds_t, int);
+extern grpc_poll_function_type grpc_poll_function;
+
 #endif /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H */
diff --git a/src/core/iomgr/pollset_windows.c b/src/core/iomgr/pollset_windows.c
index 22dc5891c3..07522c8a0c 100644
--- a/src/core/iomgr/pollset_windows.c
+++ b/src/core/iomgr/pollset_windows.c
@@ -56,8 +56,7 @@ static grpc_pollset_worker *pop_front_worker(grpc_pollset *p) {
     grpc_pollset_worker *w = p->root_worker.next;
     remove_worker(p, w);
     return w;
-  }
-  else {
+  } else {
     return NULL;
   }
 }
@@ -100,13 +99,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset) {
   gpr_mu_destroy(&pollset->mu);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker, gpr_timespec deadline) {
-  gpr_timespec now;
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker, 
+                       gpr_timespec now, gpr_timespec deadline) {
   int added_worker = 0;
-  now = gpr_now(GPR_CLOCK_MONOTONIC);
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0 /* GPR_FALSE */;
-  }
   worker->next = worker->prev = NULL;
   gpr_cv_init(&worker->cv);
   if (grpc_maybe_call_delayed_callbacks(&pollset->mu, 1 /* GPR_TRUE */)) {
@@ -127,15 +122,14 @@ done:
   if (added_worker) {
     remove_worker(pollset, worker);
   }
-  return 1 /* GPR_TRUE */;
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {
   if (specific_worker != NULL) {
     if (specific_worker == GRPC_POLLSET_KICK_BROADCAST) {
       for (specific_worker = p->root_worker.next;
-        specific_worker != &p->root_worker;
-        specific_worker = specific_worker->next) {
+           specific_worker != &p->root_worker;
+           specific_worker = specific_worker->next) {
         gpr_cv_signal(&specific_worker->cv);
       }
       p->kicked_without_pollers = 1;
diff --git a/src/core/iomgr/resolve_address.h b/src/core/iomgr/resolve_address.h
index 8f1d7a22bb..cc1bd428b0 100644
--- a/src/core/iomgr/resolve_address.h
+++ b/src/core/iomgr/resolve_address.h
@@ -66,4 +66,4 @@ void grpc_resolved_addresses_destroy(grpc_resolved_addresses *addresses);
 grpc_resolved_addresses *grpc_blocking_resolve_address(
     const char *addr, const char *default_port);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_RESOLVE_ADDRESS_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_RESOLVE_ADDRESS_H */
diff --git a/src/core/iomgr/resolve_address_posix.c b/src/core/iomgr/resolve_address_posix.c
index dbf884c769..ce6972b797 100644
--- a/src/core/iomgr/resolve_address_posix.c
+++ b/src/core/iomgr/resolve_address_posix.c
@@ -105,10 +105,7 @@ grpc_resolved_addresses *grpc_blocking_resolve_address(
   s = getaddrinfo(host, port, &hints, &result);
   if (s != 0) {
     /* Retry if well-known service name is recognized */
-    char *svc[][2] = {
-      {"http", "80"},
-      {"https", "443"}
-    };
+    char *svc[][2] = {{"http", "80"}, {"https", "443"}};
     int i;
     for (i = 0; i < (int)(sizeof(svc) / sizeof(svc[0])); i++) {
       if (strcmp(port, svc[i][0]) == 0) {
diff --git a/src/core/iomgr/sockaddr.h b/src/core/iomgr/sockaddr.h
index 7528db73b8..e41e1ec6b4 100644
--- a/src/core/iomgr/sockaddr.h
+++ b/src/core/iomgr/sockaddr.h
@@ -44,4 +44,4 @@
 #include "src/core/iomgr/sockaddr_posix.h"
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_H */
diff --git a/src/core/iomgr/sockaddr_posix.h b/src/core/iomgr/sockaddr_posix.h
index 2a3d932f70..388abb3306 100644
--- a/src/core/iomgr/sockaddr_posix.h
+++ b/src/core/iomgr/sockaddr_posix.h
@@ -41,4 +41,4 @@
 #include <netdb.h>
 #include <unistd.h>
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_POSIX_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_POSIX_H */
diff --git a/src/core/iomgr/sockaddr_utils.c b/src/core/iomgr/sockaddr_utils.c
index 65ec1f94ac..efdc480365 100644
--- a/src/core/iomgr/sockaddr_utils.c
+++ b/src/core/iomgr/sockaddr_utils.c
@@ -206,7 +206,8 @@ int grpc_sockaddr_get_port(const struct sockaddr *addr) {
     case AF_UNIX:
       return 1;
     default:
-      gpr_log(GPR_ERROR, "Unknown socket family %d in grpc_sockaddr_get_port", addr->sa_family);
+      gpr_log(GPR_ERROR, "Unknown socket family %d in grpc_sockaddr_get_port",
+              addr->sa_family);
       return 0;
   }
 }
@@ -220,7 +221,8 @@ int grpc_sockaddr_set_port(const struct sockaddr *addr, int port) {
       ((struct sockaddr_in6 *)addr)->sin6_port = htons(port);
       return 1;
     default:
-      gpr_log(GPR_ERROR, "Unknown socket family %d in grpc_sockaddr_set_port", addr->sa_family);
+      gpr_log(GPR_ERROR, "Unknown socket family %d in grpc_sockaddr_set_port",
+              addr->sa_family);
       return 0;
   }
 }
diff --git a/src/core/iomgr/sockaddr_utils.h b/src/core/iomgr/sockaddr_utils.h
index 99f1ed54da..6f7a279900 100644
--- a/src/core/iomgr/sockaddr_utils.h
+++ b/src/core/iomgr/sockaddr_utils.h
@@ -86,4 +86,4 @@ int grpc_sockaddr_to_string(char **out, const struct sockaddr *addr,
 
 char *grpc_sockaddr_to_uri(const struct sockaddr *addr);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_UTILS_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_UTILS_H */
diff --git a/src/core/iomgr/sockaddr_win32.h b/src/core/iomgr/sockaddr_win32.h
index be55db805a..fe2be99145 100644
--- a/src/core/iomgr/sockaddr_win32.h
+++ b/src/core/iomgr/sockaddr_win32.h
@@ -43,4 +43,4 @@
 const char *inet_ntop(int af, const void *src, char *dst, socklen_t size);
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_WIN32_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKADDR_WIN32_H */
diff --git a/src/core/iomgr/socket_utils_posix.h b/src/core/iomgr/socket_utils_posix.h
index d2a315b462..d330d1986e 100644
--- a/src/core/iomgr/socket_utils_posix.h
+++ b/src/core/iomgr/socket_utils_posix.h
@@ -110,4 +110,4 @@ extern int grpc_forbid_dualstack_sockets_for_testing;
 int grpc_create_dualstack_socket(const struct sockaddr *addr, int type,
                                  int protocol, grpc_dualstack_mode *dsmode);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_UTILS_POSIX_H */
diff --git a/src/core/iomgr/socket_windows.c b/src/core/iomgr/socket_windows.c
index f6ddfff0ad..7d8421376b 100644
--- a/src/core/iomgr/socket_windows.c
+++ b/src/core/iomgr/socket_windows.c
@@ -106,4 +106,4 @@ void grpc_winsocket_destroy(grpc_winsocket *winsocket) {
   gpr_free(winsocket);
 }
 
-#endif  /* GPR_WINSOCK_SOCKET */
+#endif /* GPR_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/socket_windows.h b/src/core/iomgr/socket_windows.h
index 346fde8edd..ecf2530173 100644
--- a/src/core/iomgr/socket_windows.h
+++ b/src/core/iomgr/socket_windows.h
@@ -54,7 +54,7 @@ typedef struct grpc_winsocket_callback_info {
   OVERLAPPED overlapped;
   /* The callback information for the pending operation. May be empty if the
      caller hasn't registered a callback yet. */
-  void(*cb)(void *opaque, int success);
+  void (*cb)(void *opaque, int success);
   void *opaque;
   /* A boolean to describe if the IO Completion Port got a notification for
      that operation. This will happen if the operation completed before the
@@ -118,4 +118,4 @@ void grpc_winsocket_orphan(grpc_winsocket *socket);
    or by grpc_winsocket_orphan if there's no pending operation. */
 void grpc_winsocket_destroy(grpc_winsocket *socket);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_WINDOWS_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_SOCKET_WINDOWS_H */
diff --git a/src/core/iomgr/tcp_client.h b/src/core/iomgr/tcp_client.h
index 0fa08b52b0..8ad9b818e1 100644
--- a/src/core/iomgr/tcp_client.h
+++ b/src/core/iomgr/tcp_client.h
@@ -41,7 +41,7 @@
 
 /* Asynchronously connect to an address (specified as (addr, len)), and call
    cb with arg and the completed connection when done (or call cb with arg and
-   NULL on failure). 
+   NULL on failure).
    interested_parties points to a set of pollsets that would be interested
    in this connection being established (in order to continue their work) */
 void grpc_tcp_client_connect(void (*cb)(void *arg, grpc_endpoint *tcp),
diff --git a/src/core/iomgr/tcp_client_posix.c b/src/core/iomgr/tcp_client_posix.c
index 9572ce5980..66027f87a0 100644
--- a/src/core/iomgr/tcp_client_posix.c
+++ b/src/core/iomgr/tcp_client_posix.c
@@ -264,7 +264,8 @@ void grpc_tcp_client_connect(void (*cb)(void *arg, grpc_endpoint *ep),
   ac->write_closure.cb_arg = ac;
 
   gpr_mu_lock(&ac->mu);
-  grpc_alarm_init(&ac->alarm, gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC), 
+  grpc_alarm_init(&ac->alarm,
+                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
                   tc_on_alarm, ac, gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_fd_notify_on_write(ac->fd, &ac->write_closure);
   gpr_mu_unlock(&ac->mu);
diff --git a/src/core/iomgr/tcp_posix.c b/src/core/iomgr/tcp_posix.c
index 24fee0596f..360e6ebd8c 100644
--- a/src/core/iomgr/tcp_posix.c
+++ b/src/core/iomgr/tcp_posix.c
@@ -572,7 +572,8 @@ static void grpc_tcp_add_to_pollset(grpc_endpoint *ep, grpc_pollset *pollset) {
   grpc_pollset_add_fd(pollset, tcp->em_fd);
 }
 
-static void grpc_tcp_add_to_pollset_set(grpc_endpoint *ep, grpc_pollset_set *pollset_set) {
+static void grpc_tcp_add_to_pollset_set(grpc_endpoint *ep,
+                                        grpc_pollset_set *pollset_set) {
   grpc_tcp *tcp = (grpc_tcp *)ep;
   grpc_pollset_set_add_fd(pollset_set, tcp->em_fd);
 }
diff --git a/src/core/iomgr/tcp_posix.h b/src/core/iomgr/tcp_posix.h
index d752feaeea..40b3ae2679 100644
--- a/src/core/iomgr/tcp_posix.h
+++ b/src/core/iomgr/tcp_posix.h
@@ -56,4 +56,4 @@ extern int grpc_tcp_trace;
 grpc_endpoint *grpc_tcp_create(grpc_fd *fd, size_t read_slice_size,
                                const char *peer_string);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_TCP_POSIX_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_TCP_POSIX_H */
diff --git a/src/core/iomgr/tcp_server_windows.c b/src/core/iomgr/tcp_server_windows.c
index 0adbe9507c..d0478d3604 100644
--- a/src/core/iomgr/tcp_server_windows.c
+++ b/src/core/iomgr/tcp_server_windows.c
@@ -79,7 +79,8 @@ struct grpc_tcp_server {
 
   /* active port count: how many ports are actually still listening */
   int active_ports;
-  /* number of iomgr callbacks that have been explicitly scheduled during shutdown */
+  /* number of iomgr callbacks that have been explicitly scheduled during
+   * shutdown */
   int iomgr_callbacks_pending;
 
   /* all listening ports */
@@ -292,7 +293,7 @@ static void on_accept(void *arg, int from_iocp) {
       and act accordingly. */
   transfered_bytes = 0;
   wsa_success = WSAGetOverlappedResult(sock, &info->overlapped,
-                                            &transfered_bytes, FALSE, &flags);
+                                       &transfered_bytes, FALSE, &flags);
   if (!wsa_success) {
     if (sp->shutting_down) {
       /* During the shutdown case, we ARE expecting an error. So that's well,
@@ -309,16 +310,15 @@ static void on_accept(void *arg, int from_iocp) {
     if (!sp->shutting_down) {
       peer_name_string = NULL;
       err = setsockopt(sock, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
-                       (char *)&sp->socket->socket,
-                       sizeof(sp->socket->socket));
+                       (char *)&sp->socket->socket, sizeof(sp->socket->socket));
       if (err) {
         char *utf8_message = gpr_format_message(WSAGetLastError());
         gpr_log(GPR_ERROR, "setsockopt error: %s", utf8_message);
         gpr_free(utf8_message);
       }
-      err = getpeername(sock, (struct sockaddr*)&peer_name, &peer_name_len);
+      err = getpeername(sock, (struct sockaddr *)&peer_name, &peer_name_len);
       if (!err) {
-        peer_name_string = grpc_sockaddr_to_uri((struct sockaddr*)&peer_name);
+        peer_name_string = grpc_sockaddr_to_uri((struct sockaddr *)&peer_name);
       } else {
         char *utf8_message = gpr_format_message(WSAGetLastError());
         gpr_log(GPR_ERROR, "getpeername error: %s", utf8_message);
diff --git a/src/core/iomgr/tcp_windows.c b/src/core/iomgr/tcp_windows.c
index 89aa741470..901793ec43 100644
--- a/src/core/iomgr/tcp_windows.c
+++ b/src/core/iomgr/tcp_windows.c
@@ -55,24 +55,22 @@ static int set_non_block(SOCKET sock) {
   int status;
   unsigned long param = 1;
   DWORD ret;
-  status = WSAIoctl(sock, FIONBIO, &param, sizeof(param), NULL, 0, &ret,
-                    NULL, NULL);
+  status =
+      WSAIoctl(sock, FIONBIO, &param, sizeof(param), NULL, 0, &ret, NULL, NULL);
   return status == 0;
 }
 
 static int set_dualstack(SOCKET sock) {
   int status;
   unsigned long param = 0;
-  status = setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY,
-                      (const char *) &param, sizeof(param));
+  status = setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char *)&param,
+                      sizeof(param));
   return status == 0;
 }
 
 int grpc_tcp_prepare_socket(SOCKET sock) {
-  if (!set_non_block(sock))
-    return 0;
-  if (!set_dualstack(sock))
-    return 0;
+  if (!set_non_block(sock)) return 0;
+  if (!set_dualstack(sock)) return 0;
   return 1;
 }
 
@@ -100,9 +98,7 @@ typedef struct grpc_tcp {
   char *peer_string;
 } grpc_tcp;
 
-static void tcp_ref(grpc_tcp *tcp) {
-  gpr_ref(&tcp->refcount);
-}
+static void tcp_ref(grpc_tcp *tcp) { gpr_ref(&tcp->refcount); }
 
 static void tcp_unref(grpc_tcp *tcp) {
   if (gpr_unref(&tcp->refcount)) {
@@ -116,7 +112,7 @@ static void tcp_unref(grpc_tcp *tcp) {
 
 /* Asynchronous callback from the IOCP, or the background thread. */
 static void on_read(void *tcpp, int from_iocp) {
-  grpc_tcp *tcp = (grpc_tcp *) tcpp;
+  grpc_tcp *tcp = (grpc_tcp *)tcpp;
   grpc_winsocket *socket = tcp->socket;
   gpr_slice sub;
   gpr_slice *slice = NULL;
@@ -156,6 +152,7 @@ static void on_read(void *tcpp, int from_iocp) {
       gpr_log(GPR_ERROR, "ReadFile overlapped error: %s", utf8_message);
       gpr_free(utf8_message);
     }
+    gpr_slice_unref(tcp->read_slice);
     status = GRPC_ENDPOINT_CB_ERROR;
   } else {
     if (info->bytes_transfered != 0) {
@@ -175,9 +172,9 @@ static void on_read(void *tcpp, int from_iocp) {
   cb(opaque, slice, nslices, status);
 }
 
-static void win_notify_on_read(grpc_endpoint *ep,
-                               grpc_endpoint_read_cb cb, void *arg) {
-  grpc_tcp *tcp = (grpc_tcp *) ep;
+static void win_notify_on_read(grpc_endpoint *ep, grpc_endpoint_read_cb cb,
+                               void *arg) {
+  grpc_tcp *tcp = (grpc_tcp *)ep;
   grpc_winsocket *handle = tcp->socket;
   grpc_winsocket_callback_info *info = &handle->read_info;
   int status;
@@ -201,8 +198,8 @@ static void win_notify_on_read(grpc_endpoint *ep,
   buffer.buf = (char *)GPR_SLICE_START_PTR(tcp->read_slice);
 
   /* First let's try a synchronous, non-blocking read. */
-  status = WSARecv(tcp->socket->socket, &buffer, 1, &bytes_read, &flags,
-                   NULL, NULL);
+  status =
+      WSARecv(tcp->socket->socket, &buffer, 1, &bytes_read, &flags, NULL, NULL);
   info->wsa_error = status == 0 ? 0 : WSAGetLastError();
 
   /* Did we get data immediately ? Yay. */
@@ -232,7 +229,7 @@ static void win_notify_on_read(grpc_endpoint *ep,
 
 /* Asynchronous callback from the IOCP, or the background thread. */
 static void on_write(void *tcpp, int from_iocp) {
-  grpc_tcp *tcp = (grpc_tcp *) tcpp;
+  grpc_tcp *tcp = (grpc_tcp *)tcpp;
   grpc_winsocket *handle = tcp->socket;
   grpc_winsocket_callback_info *info = &handle->write_info;
   grpc_endpoint_cb_status status = GRPC_ENDPOINT_CB_OK;
@@ -286,7 +283,7 @@ static grpc_endpoint_write_status win_write(grpc_endpoint *ep,
                                             gpr_slice *slices, size_t nslices,
                                             grpc_endpoint_write_cb cb,
                                             void *arg) {
-  grpc_tcp *tcp = (grpc_tcp *) ep;
+  grpc_tcp *tcp = (grpc_tcp *)ep;
   grpc_winsocket *socket = tcp->socket;
   grpc_winsocket_callback_info *info = &socket->write_info;
   unsigned i;
@@ -309,7 +306,7 @@ static grpc_endpoint_write_status win_write(grpc_endpoint *ep,
   gpr_slice_buffer_addn(&tcp->write_slices, slices, nslices);
 
   if (tcp->write_slices.count > GPR_ARRAY_SIZE(local_buffers)) {
-    buffers = (WSABUF *) gpr_malloc(sizeof(WSABUF) * tcp->write_slices.count);
+    buffers = (WSABUF *)gpr_malloc(sizeof(WSABUF) * tcp->write_slices.count);
     allocated = buffers;
   }
 
@@ -370,15 +367,15 @@ static grpc_endpoint_write_status win_write(grpc_endpoint *ep,
 
 static void win_add_to_pollset(grpc_endpoint *ep, grpc_pollset *ps) {
   grpc_tcp *tcp;
-  (void) ps;
-  tcp = (grpc_tcp *) ep;
+  (void)ps;
+  tcp = (grpc_tcp *)ep;
   grpc_iocp_add_socket(tcp->socket);
 }
 
 static void win_add_to_pollset_set(grpc_endpoint *ep, grpc_pollset_set *pss) {
   grpc_tcp *tcp;
-  (void) pss;
-  tcp = (grpc_tcp *) ep;
+  (void)pss;
+  tcp = (grpc_tcp *)ep;
   grpc_iocp_add_socket(tcp->socket);
 }
 
@@ -389,7 +386,7 @@ static void win_add_to_pollset_set(grpc_endpoint *ep, grpc_pollset_set *pss) {
    callback will happen from another thread, so we need to protect against
    concurrent access of the data structure in that regard. */
 static void win_shutdown(grpc_endpoint *ep) {
-  grpc_tcp *tcp = (grpc_tcp *) ep;
+  grpc_tcp *tcp = (grpc_tcp *)ep;
   int extra_refs = 0;
   gpr_mu_lock(&tcp->mu);
   /* At that point, what may happen is that we're already inside the IOCP
@@ -401,7 +398,7 @@ static void win_shutdown(grpc_endpoint *ep) {
 }
 
 static void win_destroy(grpc_endpoint *ep) {
-  grpc_tcp *tcp = (grpc_tcp *) ep;
+  grpc_tcp *tcp = (grpc_tcp *)ep;
   tcp_unref(tcp);
 }
 
@@ -410,13 +407,12 @@ static char *win_get_peer(grpc_endpoint *ep) {
   return gpr_strdup(tcp->peer_string);
 }
 
-static grpc_endpoint_vtable vtable = {win_notify_on_read, win_write,
-                                      win_add_to_pollset, win_add_to_pollset_set,
-                                      win_shutdown,       win_destroy,
-                                      win_get_peer};
+static grpc_endpoint_vtable vtable = {
+    win_notify_on_read, win_write,   win_add_to_pollset, win_add_to_pollset_set,
+    win_shutdown,       win_destroy, win_get_peer};
 
 grpc_endpoint *grpc_tcp_create(grpc_winsocket *socket, char *peer_string) {
-  grpc_tcp *tcp = (grpc_tcp *) gpr_malloc(sizeof(grpc_tcp));
+  grpc_tcp *tcp = (grpc_tcp *)gpr_malloc(sizeof(grpc_tcp));
   memset(tcp, 0, sizeof(grpc_tcp));
   tcp->base.vtable = &vtable;
   tcp->socket = socket;
@@ -427,4 +423,4 @@ grpc_endpoint *grpc_tcp_create(grpc_winsocket *socket, char *peer_string) {
   return &tcp->base;
 }
 
-#endif  /* GPR_WINSOCK_SOCKET */
+#endif /* GPR_WINSOCK_SOCKET */
diff --git a/src/core/iomgr/tcp_windows.h b/src/core/iomgr/tcp_windows.h
index 7e301db250..deb3e48293 100644
--- a/src/core/iomgr/tcp_windows.h
+++ b/src/core/iomgr/tcp_windows.h
@@ -54,4 +54,4 @@ grpc_endpoint *grpc_tcp_create(grpc_winsocket *socket, char *peer_string);
 
 int grpc_tcp_prepare_socket(SOCKET sock);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_TCP_WINDOWS_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_TCP_WINDOWS_H */
diff --git a/src/core/iomgr/time_averaged_stats.h b/src/core/iomgr/time_averaged_stats.h
index 13894b2640..e6dec1b4cd 100644
--- a/src/core/iomgr/time_averaged_stats.h
+++ b/src/core/iomgr/time_averaged_stats.h
@@ -85,4 +85,4 @@ void grpc_time_averaged_stats_add_sample(grpc_time_averaged_stats *stats,
    value. */
 double grpc_time_averaged_stats_update_average(grpc_time_averaged_stats *stats);
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_TIME_AVERAGED_STATS_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_TIME_AVERAGED_STATS_H */
diff --git a/src/core/iomgr/udp_server.c b/src/core/iomgr/udp_server.c
index db0aef8120..6429c38b28 100644
--- a/src/core/iomgr/udp_server.c
+++ b/src/core/iomgr/udp_server.c
@@ -232,11 +232,13 @@ static int prepare_socket(int fd, const struct sockaddr *addr, int addr_len) {
   }
 
   get_local_ip = 1;
-  rc = setsockopt(fd, IPPROTO_IP, IP_PKTINFO,
-                      &get_local_ip, sizeof(get_local_ip));
+  rc = setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &get_local_ip,
+                  sizeof(get_local_ip));
   if (rc == 0 && addr->sa_family == AF_INET6) {
-    rc = setsockopt(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
-                    &get_local_ip, sizeof(get_local_ip));
+#if !TARGET_OS_IPHONE
+    rc = setsockopt(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &get_local_ip,
+                    sizeof(get_local_ip));
+#endif
   }
 
   if (bind(fd, addr, addr_len) < 0) {
@@ -317,8 +319,8 @@ static int add_socket_to_server(grpc_udp_server *s, int fd,
   return port;
 }
 
-int grpc_udp_server_add_port(grpc_udp_server *s, const void *addr,
-                             int addr_len, grpc_udp_server_read_cb read_cb) {
+int grpc_udp_server_add_port(grpc_udp_server *s, const void *addr, int addr_len,
+                             grpc_udp_server_read_cb read_cb) {
   int allocated_port1 = -1;
   int allocated_port2 = -1;
   unsigned i;
diff --git a/src/core/iomgr/wakeup_fd_eventfd.c b/src/core/iomgr/wakeup_fd_eventfd.c
index 52912235f8..08fdc74f17 100644
--- a/src/core/iomgr/wakeup_fd_eventfd.c
+++ b/src/core/iomgr/wakeup_fd_eventfd.c
@@ -75,8 +75,7 @@ static int eventfd_check_availability(void) {
 }
 
 const grpc_wakeup_fd_vtable grpc_specialized_wakeup_fd_vtable = {
-  eventfd_create, eventfd_consume, eventfd_wakeup, eventfd_destroy,
-  eventfd_check_availability
-};
+    eventfd_create, eventfd_consume, eventfd_wakeup, eventfd_destroy,
+    eventfd_check_availability};
 
 #endif /* GPR_LINUX_EVENTFD */
diff --git a/src/core/iomgr/wakeup_fd_nospecial.c b/src/core/iomgr/wakeup_fd_nospecial.c
index c1038bf379..78d763c103 100644
--- a/src/core/iomgr/wakeup_fd_nospecial.c
+++ b/src/core/iomgr/wakeup_fd_nospecial.c
@@ -43,12 +43,9 @@
 #include "src/core/iomgr/wakeup_fd_posix.h"
 #include <stddef.h>
 
-static int check_availability_invalid(void) {
-  return 0;
-}
+static int check_availability_invalid(void) { return 0; }
 
 const grpc_wakeup_fd_vtable grpc_specialized_wakeup_fd_vtable = {
-  NULL, NULL, NULL, NULL, check_availability_invalid
-};
+    NULL, NULL, NULL, NULL, check_availability_invalid};
 
-#endif  /* GPR_POSIX_NO_SPECIAL_WAKEUP_FD */
+#endif /* GPR_POSIX_NO_SPECIAL_WAKEUP_FD */
diff --git a/src/core/iomgr/wakeup_fd_pipe.c b/src/core/iomgr/wakeup_fd_pipe.c
index 9fc4ee2388..bd643e8061 100644
--- a/src/core/iomgr/wakeup_fd_pipe.c
+++ b/src/core/iomgr/wakeup_fd_pipe.c
@@ -94,4 +94,4 @@ const grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable = {
     pipe_init, pipe_consume, pipe_wakeup, pipe_destroy,
     pipe_check_availability};
 
-#endif  /* GPR_POSIX_WAKUP_FD */
+#endif /* GPR_POSIX_WAKUP_FD */
diff --git a/src/core/iomgr/wakeup_fd_pipe.h b/src/core/iomgr/wakeup_fd_pipe.h
index aa8f977ddb..01a13a97c0 100644
--- a/src/core/iomgr/wakeup_fd_pipe.h
+++ b/src/core/iomgr/wakeup_fd_pipe.h
@@ -38,4 +38,4 @@
 
 extern grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable;
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_PIPE_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_PIPE_H */
diff --git a/src/core/iomgr/wakeup_fd_posix.c b/src/core/iomgr/wakeup_fd_posix.c
index e48f5223fa..d09fb78d12 100644
--- a/src/core/iomgr/wakeup_fd_posix.c
+++ b/src/core/iomgr/wakeup_fd_posix.c
@@ -53,9 +53,7 @@ void grpc_wakeup_fd_global_init_force_fallback(void) {
   wakeup_fd_vtable = &grpc_pipe_wakeup_fd_vtable;
 }
 
-void grpc_wakeup_fd_global_destroy(void) {
-  wakeup_fd_vtable = NULL;
-}
+void grpc_wakeup_fd_global_destroy(void) { wakeup_fd_vtable = NULL; }
 
 void grpc_wakeup_fd_init(grpc_wakeup_fd *fd_info) {
   wakeup_fd_vtable->init(fd_info);
@@ -73,4 +71,4 @@ void grpc_wakeup_fd_destroy(grpc_wakeup_fd *fd_info) {
   wakeup_fd_vtable->destroy(fd_info);
 }
 
-#endif  /* GPR_POSIX_WAKEUP_FD */
+#endif /* GPR_POSIX_WAKEUP_FD */
diff --git a/src/core/iomgr/wakeup_fd_posix.h b/src/core/iomgr/wakeup_fd_posix.h
index a4da4df51f..b6c086900d 100644
--- a/src/core/iomgr/wakeup_fd_posix.h
+++ b/src/core/iomgr/wakeup_fd_posix.h
@@ -96,4 +96,4 @@ void grpc_wakeup_fd_destroy(grpc_wakeup_fd *fd_info);
  * wakeup_fd_nospecial.c if no such implementation exists. */
 extern const grpc_wakeup_fd_vtable grpc_specialized_wakeup_fd_vtable;
 
-#endif  /* GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_POSIX_H */
+#endif /* GRPC_INTERNAL_CORE_IOMGR_WAKEUP_FD_POSIX_H */
diff --git a/src/core/json/json.h b/src/core/json/json.h
index cac18ad885..573584bf6f 100644
--- a/src/core/json/json.h
+++ b/src/core/json/json.h
@@ -85,4 +85,4 @@ char* grpc_json_dump_to_string(grpc_json* json, int indent);
 grpc_json* grpc_json_create(grpc_json_type type);
 void grpc_json_destroy(grpc_json* json);
 
-#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_H */
+#endif /* GRPC_INTERNAL_CORE_JSON_JSON_H */
diff --git a/src/core/json/json_common.h b/src/core/json/json_common.h
index 84bf375916..481695b38b 100644
--- a/src/core/json/json_common.h
+++ b/src/core/json/json_common.h
@@ -46,4 +46,4 @@ typedef enum {
   GRPC_JSON_TOP_LEVEL
 } grpc_json_type;
 
-#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_COMMON_H */
+#endif /* GRPC_INTERNAL_CORE_JSON_JSON_COMMON_H */
diff --git a/src/core/json/json_reader.c b/src/core/json/json_reader.c
index c14094c290..c22d4edd47 100644
--- a/src/core/json/json_reader.c
+++ b/src/core/json/json_reader.c
@@ -42,27 +42,26 @@ static void json_reader_string_clear(grpc_json_reader* reader) {
 }
 
 static void json_reader_string_add_char(grpc_json_reader* reader,
-                                             gpr_uint32 c) {
+                                        gpr_uint32 c) {
   reader->vtable->string_add_char(reader->userdata, c);
 }
 
 static void json_reader_string_add_utf32(grpc_json_reader* reader,
-                                              gpr_uint32 utf32) {
+                                         gpr_uint32 utf32) {
   reader->vtable->string_add_utf32(reader->userdata, utf32);
 }
 
-static gpr_uint32
-    grpc_json_reader_read_char(grpc_json_reader* reader) {
+static gpr_uint32 grpc_json_reader_read_char(grpc_json_reader* reader) {
   return reader->vtable->read_char(reader->userdata);
 }
 
 static void json_reader_container_begins(grpc_json_reader* reader,
-                                              grpc_json_type type) {
+                                         grpc_json_type type) {
   reader->vtable->container_begins(reader->userdata, type);
 }
 
-static grpc_json_type
-    grpc_json_reader_container_ends(grpc_json_reader* reader) {
+static grpc_json_type grpc_json_reader_container_ends(
+    grpc_json_reader* reader) {
   return reader->vtable->container_ends(reader->userdata);
 }
 
@@ -101,8 +100,9 @@ void grpc_json_reader_init(grpc_json_reader* reader,
 }
 
 int grpc_json_reader_is_complete(grpc_json_reader* reader) {
-  return ((reader->depth == 0) && ((reader->state == GRPC_JSON_STATE_END) ||
-          (reader->state == GRPC_JSON_STATE_VALUE_END)));
+  return ((reader->depth == 0) &&
+          ((reader->state == GRPC_JSON_STATE_END) ||
+           (reader->state == GRPC_JSON_STATE_VALUE_END)));
 }
 
 grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
@@ -143,7 +143,8 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
           case GRPC_JSON_STATE_OBJECT_KEY_STRING:
           case GRPC_JSON_STATE_VALUE_STRING:
             if (c != ' ') return GRPC_JSON_PARSE_ERROR;
-            if (reader->unicode_high_surrogate != 0) return GRPC_JSON_PARSE_ERROR;
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
             json_reader_string_add_char(reader, c);
             break;
 
@@ -169,7 +170,8 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
         switch (reader->state) {
           case GRPC_JSON_STATE_OBJECT_KEY_STRING:
           case GRPC_JSON_STATE_VALUE_STRING:
-            if (reader->unicode_high_surrogate != 0) return GRPC_JSON_PARSE_ERROR;
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
             json_reader_string_add_char(reader, c);
             break;
 
@@ -253,7 +255,8 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
 
           /* This is the \\ case. */
           case GRPC_JSON_STATE_STRING_ESCAPE:
-            if (reader->unicode_high_surrogate != 0) return GRPC_JSON_PARSE_ERROR;
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
             json_reader_string_add_char(reader, '\\');
             if (reader->escaped_string_was_key) {
               reader->state = GRPC_JSON_STATE_OBJECT_KEY_STRING;
@@ -276,7 +279,8 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
             break;
 
           case GRPC_JSON_STATE_OBJECT_KEY_STRING:
-            if (reader->unicode_high_surrogate != 0) return GRPC_JSON_PARSE_ERROR;
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
             if (c == '"') {
               reader->state = GRPC_JSON_STATE_OBJECT_KEY_END;
               json_reader_set_key(reader);
@@ -288,7 +292,8 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
             break;
 
           case GRPC_JSON_STATE_VALUE_STRING:
-            if (reader->unicode_high_surrogate != 0) return GRPC_JSON_PARSE_ERROR;
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
             if (c == '"') {
               reader->state = GRPC_JSON_STATE_VALUE_END;
               json_reader_set_string(reader);
@@ -438,7 +443,8 @@ grpc_json_reader_status grpc_json_reader_run(grpc_json_reader* reader) {
                   if (reader->unicode_high_surrogate == 0)
                     return GRPC_JSON_PARSE_ERROR;
                   utf32 = 0x10000;
-                  utf32 += (gpr_uint32)((reader->unicode_high_surrogate - 0xd800) * 0x400);
+                  utf32 += (gpr_uint32)(
+                      (reader->unicode_high_surrogate - 0xd800) * 0x400);
                   utf32 += (gpr_uint32)(reader->unicode_char - 0xdc00);
                   json_reader_string_add_utf32(reader, utf32);
                   reader->unicode_high_surrogate = 0;
diff --git a/src/core/json/json_reader.h b/src/core/json/json_reader.h
index b1a5ace8fb..4d5487f790 100644
--- a/src/core/json/json_reader.h
+++ b/src/core/json/json_reader.h
@@ -157,4 +157,4 @@ void grpc_json_reader_init(grpc_json_reader* reader,
  */
 int grpc_json_reader_is_complete(grpc_json_reader* reader);
 
-#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_READER_H */
+#endif /* GRPC_INTERNAL_CORE_JSON_JSON_READER_H */
diff --git a/src/core/json/json_string.c b/src/core/json/json_string.c
index 03c1099167..e6622ec461 100644
--- a/src/core/json/json_string.c
+++ b/src/core/json/json_string.c
@@ -73,7 +73,6 @@ typedef struct {
   size_t allocated;
 } json_writer_userdata;
 
-
 /* This function checks if there's enough space left in the output buffer,
  * and will enlarge it if necessary. We're only allocating chunks of 256
  * bytes at a time (or multiples thereof).
@@ -97,8 +96,8 @@ static void json_writer_output_char(void* userdata, char c) {
   state->free_space--;
 }
 
-static void json_writer_output_string_with_len(void* userdata,
-                                               const char* str, size_t len) {
+static void json_writer_output_string_with_len(void* userdata, const char* str,
+                                               size_t len) {
   json_writer_userdata* state = userdata;
   json_writer_output_check(userdata, len);
   memcpy(state->output + state->string_len, str, len);
@@ -106,8 +105,7 @@ static void json_writer_output_string_with_len(void* userdata,
   state->free_space -= len;
 }
 
-static void json_writer_output_string(void* userdata,
-                                           const char* str) {
+static void json_writer_output_string(void* userdata, const char* str) {
   size_t len = strlen(str);
   json_writer_output_string_with_len(userdata, str, len);
 }
@@ -184,8 +182,7 @@ static gpr_uint32 json_reader_read_char(void* userdata) {
 /* Helper function to create a new grpc_json object and link it into
  * our tree-in-progress inside our opaque structure.
  */
-static grpc_json* json_create_and_link(void* userdata,
-                                       grpc_json_type type) {
+static grpc_json* json_create_and_link(void* userdata, grpc_json_type type) {
   json_reader_userdata* state = userdata;
   grpc_json* json = grpc_json_create(type);
 
@@ -201,7 +198,7 @@ static grpc_json* json_create_and_link(void* userdata,
       json->parent->child = json;
     }
     if (json->parent->type == GRPC_JSON_OBJECT) {
-      json->key = (char*) state->key;
+      json->key = (char*)state->key;
     }
   }
   if (!state->top) {
@@ -261,13 +258,13 @@ static void json_reader_set_key(void* userdata) {
 static void json_reader_set_string(void* userdata) {
   json_reader_userdata* state = userdata;
   grpc_json* json = json_create_and_link(userdata, GRPC_JSON_STRING);
-  json->value = (char*) state->string;
+  json->value = (char*)state->string;
 }
 
 static int json_reader_set_number(void* userdata) {
   json_reader_userdata* state = userdata;
   grpc_json* json = json_create_and_link(userdata, GRPC_JSON_NUMBER);
-  json->value = (char*) state->string;
+  json->value = (char*)state->string;
   return 1;
 }
 
@@ -287,32 +284,25 @@ static void json_reader_set_null(void* userdata) {
 }
 
 static grpc_json_reader_vtable reader_vtable = {
-  json_reader_string_clear,
-  json_reader_string_add_char,
-  json_reader_string_add_utf32,
-  json_reader_read_char,
-  json_reader_container_begins,
-  json_reader_container_ends,
-  json_reader_set_key,
-  json_reader_set_string,
-  json_reader_set_number,
-  json_reader_set_true,
-  json_reader_set_false,
-  json_reader_set_null
-};
+    json_reader_string_clear,     json_reader_string_add_char,
+    json_reader_string_add_utf32, json_reader_read_char,
+    json_reader_container_begins, json_reader_container_ends,
+    json_reader_set_key,          json_reader_set_string,
+    json_reader_set_number,       json_reader_set_true,
+    json_reader_set_false,        json_reader_set_null};
 
 /* And finally, let's define our public API. */
 grpc_json* grpc_json_parse_string_with_len(char* input, size_t size) {
   grpc_json_reader reader;
   json_reader_userdata state;
-  grpc_json *json = NULL;
+  grpc_json* json = NULL;
   grpc_json_reader_status status;
 
   if (!input) return NULL;
 
   state.top = state.current_container = state.current_value = NULL;
   state.string = state.key = NULL;
-  state.string_ptr = state.input = (gpr_uint8*) input;
+  state.string_ptr = state.input = (gpr_uint8*)input;
   state.remaining_input = size;
   grpc_json_reader_init(&reader, &reader_vtable, &state);
 
@@ -333,8 +323,8 @@ grpc_json* grpc_json_parse_string(char* input) {
   return grpc_json_parse_string_with_len(input, UNBOUND_JSON_STRING_LENGTH);
 }
 
-static void json_dump_recursive(grpc_json_writer* writer,
-                                grpc_json* json, int in_object) {
+static void json_dump_recursive(grpc_json_writer* writer, grpc_json* json,
+                                int in_object) {
   while (json) {
     if (in_object) grpc_json_writer_object_key(writer, json->key);
 
@@ -370,10 +360,8 @@ static void json_dump_recursive(grpc_json_writer* writer,
 }
 
 static grpc_json_writer_vtable writer_vtable = {
-  json_writer_output_char,
-  json_writer_output_string,
-  json_writer_output_string_with_len
-};
+    json_writer_output_char, json_writer_output_string,
+    json_writer_output_string_with_len};
 
 char* grpc_json_dump_to_string(grpc_json* json, int indent) {
   grpc_json_writer writer;
diff --git a/src/core/json/json_writer.c b/src/core/json/json_writer.c
index bed9a9bfa5..ca9c835825 100644
--- a/src/core/json/json_writer.c
+++ b/src/core/json/json_writer.c
@@ -41,11 +41,13 @@ static void json_writer_output_char(grpc_json_writer* writer, char c) {
   writer->vtable->output_char(writer->userdata, c);
 }
 
-static void json_writer_output_string(grpc_json_writer* writer, const char* str) {
+static void json_writer_output_string(grpc_json_writer* writer,
+                                      const char* str) {
   writer->vtable->output_string(writer->userdata, str);
 }
 
-static void json_writer_output_string_with_len(grpc_json_writer* writer, const char* str, size_t len) {
+static void json_writer_output_string_with_len(grpc_json_writer* writer,
+                                               const char* str, size_t len) {
   writer->vtable->output_string_with_len(writer->userdata, str, len);
 }
 
@@ -58,8 +60,7 @@ void grpc_json_writer_init(grpc_json_writer* writer, int indent,
   writer->userdata = userdata;
 }
 
-static void json_writer_output_indent(
-    grpc_json_writer* writer) {
+static void json_writer_output_indent(grpc_json_writer* writer) {
   static const char spacesstr[] =
       "                "
       "                "
@@ -99,14 +100,15 @@ static void json_writer_value_end(grpc_json_writer* writer) {
   }
 }
 
-static void json_writer_escape_utf16(grpc_json_writer* writer, gpr_uint16 utf16) {
+static void json_writer_escape_utf16(grpc_json_writer* writer,
+                                     gpr_uint16 utf16) {
   static const char hex[] = "0123456789abcdef";
 
   json_writer_output_string_with_len(writer, "\\u", 2);
   json_writer_output_char(writer, hex[(utf16 >> 12) & 0x0f]);
   json_writer_output_char(writer, hex[(utf16 >> 8) & 0x0f]);
   json_writer_output_char(writer, hex[(utf16 >> 4) & 0x0f]);
-  json_writer_output_char(writer, hex[(utf16) & 0x0f]);
+  json_writer_output_char(writer, hex[(utf16)&0x0f]);
 }
 
 static void json_writer_escape_string(grpc_json_writer* writer,
@@ -173,8 +175,8 @@ static void json_writer_escape_string(grpc_json_writer* writer,
        * Any other range is technically reserved for future usage, so if we
        * don't want the software to break in the future, we have to allow
        * anything else. The first non-unicode character is 0x110000. */
-      if (((utf32 >= 0xd800) && (utf32 <= 0xdfff)) ||
-          (utf32 >= 0x110000)) break;
+      if (((utf32 >= 0xd800) && (utf32 <= 0xdfff)) || (utf32 >= 0x110000))
+        break;
       if (utf32 >= 0x10000) {
         /* If utf32 contains a character that is above 0xffff, it needs to be
          * broken down into a utf-16 surrogate pair. A surrogate pair is first
@@ -194,7 +196,8 @@ static void json_writer_escape_string(grpc_json_writer* writer,
          */
         utf32 -= 0x10000;
         json_writer_escape_utf16(writer, (gpr_uint16)(0xd800 | (utf32 >> 10)));
-        json_writer_escape_utf16(writer, (gpr_uint16)(0xdc00 | (utf32 & 0x3ff)));
+        json_writer_escape_utf16(writer,
+                                 (gpr_uint16)(0xdc00 | (utf32 & 0x3ff)));
       } else {
         json_writer_escape_utf16(writer, (gpr_uint16)utf32);
       }
@@ -204,7 +207,8 @@ static void json_writer_escape_string(grpc_json_writer* writer,
   json_writer_output_char(writer, '"');
 }
 
-void grpc_json_writer_container_begins(grpc_json_writer* writer, grpc_json_type type) {
+void grpc_json_writer_container_begins(grpc_json_writer* writer,
+                                       grpc_json_type type) {
   if (!writer->got_key) json_writer_value_end(writer);
   json_writer_output_indent(writer);
   json_writer_output_char(writer, type == GRPC_JSON_OBJECT ? '{' : '[');
@@ -213,7 +217,8 @@ void grpc_json_writer_container_begins(grpc_json_writer* writer, grpc_json_type
   writer->depth++;
 }
 
-void grpc_json_writer_container_ends(grpc_json_writer* writer, grpc_json_type type) {
+void grpc_json_writer_container_ends(grpc_json_writer* writer,
+                                     grpc_json_type type) {
   if (writer->indent && !writer->container_empty)
     json_writer_output_char(writer, '\n');
   writer->depth--;
@@ -238,14 +243,16 @@ void grpc_json_writer_value_raw(grpc_json_writer* writer, const char* string) {
   writer->got_key = 0;
 }
 
-void grpc_json_writer_value_raw_with_len(grpc_json_writer* writer, const char* string, size_t len) {
+void grpc_json_writer_value_raw_with_len(grpc_json_writer* writer,
+                                         const char* string, size_t len) {
   if (!writer->got_key) json_writer_value_end(writer);
   json_writer_output_indent(writer);
   json_writer_output_string_with_len(writer, string, len);
   writer->got_key = 0;
 }
 
-void grpc_json_writer_value_string(grpc_json_writer* writer, const char* string) {
+void grpc_json_writer_value_string(grpc_json_writer* writer,
+                                   const char* string) {
   if (!writer->got_key) json_writer_value_end(writer);
   json_writer_output_indent(writer);
   json_writer_escape_string(writer, string);
diff --git a/src/core/json/json_writer.h b/src/core/json/json_writer.h
index dfa61a5fef..a299dfabf8 100644
--- a/src/core/json/json_writer.h
+++ b/src/core/json/json_writer.h
@@ -78,16 +78,20 @@ void grpc_json_writer_init(grpc_json_writer* writer, int indent,
                            grpc_json_writer_vtable* vtable, void* userdata);
 
 /* Signals the beginning of a container. */
-void grpc_json_writer_container_begins(grpc_json_writer* writer, grpc_json_type type);
+void grpc_json_writer_container_begins(grpc_json_writer* writer,
+                                       grpc_json_type type);
 /* Signals the end of a container. */
-void grpc_json_writer_container_ends(grpc_json_writer* writer, grpc_json_type type);
+void grpc_json_writer_container_ends(grpc_json_writer* writer,
+                                     grpc_json_type type);
 /* Writes down an object key for the next value. */
 void grpc_json_writer_object_key(grpc_json_writer* writer, const char* string);
 /* Sets a raw value. Useful for numbers. */
 void grpc_json_writer_value_raw(grpc_json_writer* writer, const char* string);
 /* Sets a raw value with its length. Useful for values like true or false. */
-void grpc_json_writer_value_raw_with_len(grpc_json_writer* writer, const char* string, size_t len);
+void grpc_json_writer_value_raw_with_len(grpc_json_writer* writer,
+                                         const char* string, size_t len);
 /* Sets a string value. It'll be escaped, and utf-8 validated. */
-void grpc_json_writer_value_string(grpc_json_writer* writer, const char* string);
+void grpc_json_writer_value_string(grpc_json_writer* writer,
+                                   const char* string);
 
-#endif  /* GRPC_INTERNAL_CORE_JSON_JSON_WRITER_H */
+#endif /* GRPC_INTERNAL_CORE_JSON_JSON_WRITER_H */
diff --git a/src/core/profiling/basic_timers.c b/src/core/profiling/basic_timers.c
index ae37f584eb..4b6a0d2f56 100644
--- a/src/core/profiling/basic_timers.c
+++ b/src/core/profiling/basic_timers.c
@@ -36,7 +36,6 @@
 #ifdef GRPC_BASIC_PROFILER
 
 #include "src/core/profiling/timers.h"
-#include "src/core/profiling/timers_preciseclock.h"
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
@@ -53,7 +52,7 @@ typedef enum {
 } marker_type;
 
 typedef struct grpc_timer_entry {
-  grpc_precise_clock tm;
+  gpr_timespec tm;
   int tag;
   const char* tagstr;
   marker_type type;
@@ -71,9 +70,8 @@ static void log_report() {
   int i;
   for (i = 0; i < count; i++) {
     grpc_timer_entry* entry = &(log[i]);
-    printf("GRPC_LAT_PROF " GRPC_PRECISE_CLOCK_FORMAT
-           " %p %c %d(%s) %p %s %d\n",
-           GRPC_PRECISE_CLOCK_PRINTF_ARGS(&entry->tm),
+    printf("GRPC_LAT_PROF %ld.%09d  %p %c %d(%s) %p %s %d\n",
+           entry->tm.tv_sec, entry->tm.tv_nsec,
            (void*)(gpr_intptr)gpr_thd_currentid(), entry->type, entry->tag,
            entry->tagstr, entry->id, entry->file, entry->line);
   }
@@ -93,7 +91,7 @@ static void grpc_timers_log_add(int tag, const char* tagstr, marker_type type,
 
   entry = &log[count++];
 
-  grpc_precise_clock_now(&entry->tm);
+  entry->tm = gpr_now(GPR_CLOCK_PRECISE);
   entry->tag = tag;
   entry->tagstr = tagstr;
   entry->type = type;
diff --git a/src/core/profiling/timers.h b/src/core/profiling/timers.h
index 036d02f187..92dbab9042 100644
--- a/src/core/profiling/timers.h
+++ b/src/core/profiling/timers.h
@@ -88,7 +88,7 @@ enum grpc_profiling_tags {
   } while (0)
 
 #define GRPC_TIMER_IMPORTANT_MARK(tag, id) \
-  do {                           \
+  do {                                     \
   } while (0)
 
 #define GRPC_TIMER_BEGIN(tag, id) \
diff --git a/src/core/security/auth_filters.h b/src/core/security/auth_filters.h
index ff921690e0..c179b54bec 100644
--- a/src/core/security/auth_filters.h
+++ b/src/core/security/auth_filters.h
@@ -39,4 +39,4 @@
 extern const grpc_channel_filter grpc_client_auth_filter;
 extern const grpc_channel_filter grpc_server_auth_filter;
 
-#endif  /* GRPC_INTERNAL_CORE_SECURITY_AUTH_FILTERS_H */
+#endif /* GRPC_INTERNAL_CORE_SECURITY_AUTH_FILTERS_H */
diff --git a/src/core/security/base64.h b/src/core/security/base64.h
index b9abc07b52..31ae982691 100644
--- a/src/core/security/base64.h
+++ b/src/core/security/base64.h
@@ -49,4 +49,4 @@ gpr_slice grpc_base64_decode(const char *b64, int url_safe);
 gpr_slice grpc_base64_decode_with_len(const char *b64, size_t b64_len,
                                       int url_safe);
 
-#endif  /* GRPC_INTERNAL_CORE_SECURITY_BASE64_H */
+#endif /* GRPC_INTERNAL_CORE_SECURITY_BASE64_H */
diff --git a/src/core/security/client_auth_filter.c b/src/core/security/client_auth_filter.c
index 410852da52..8e63978b82 100644
--- a/src/core/security/client_auth_filter.c
+++ b/src/core/security/client_auth_filter.c
@@ -200,7 +200,7 @@ static void auth_start_transport_op(grpc_call_element *elem,
   channel_data *chand = elem->channel_data;
   grpc_linked_mdelem *l;
   size_t i;
-  grpc_client_security_context* sec_ctx = NULL;
+  grpc_client_security_context *sec_ctx = NULL;
 
   if (calld->security_context_set == 0) {
     calld->security_context_set = 1;
@@ -316,9 +316,11 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
       (grpc_channel_security_connector *)GRPC_SECURITY_CONNECTOR_REF(
           sc, "client_auth_filter");
   chand->md_ctx = metadata_context;
-  chand->authority_string = grpc_mdstr_from_string(chand->md_ctx, ":authority", 0);
+  chand->authority_string =
+      grpc_mdstr_from_string(chand->md_ctx, ":authority", 0);
   chand->path_string = grpc_mdstr_from_string(chand->md_ctx, ":path", 0);
-  chand->error_msg_key = grpc_mdstr_from_string(chand->md_ctx, "grpc-message", 0);
+  chand->error_msg_key =
+      grpc_mdstr_from_string(chand->md_ctx, "grpc-message", 0);
   chand->status_key = grpc_mdstr_from_string(chand->md_ctx, "grpc-status", 0);
 }
 
diff --git a/src/core/security/credentials.c b/src/core/security/credentials.c
index 6421ce673d..8852cab3e7 100644
--- a/src/core/security/credentials.c
+++ b/src/core/security/credentials.c
@@ -793,16 +793,16 @@ void on_simulated_token_fetch_done(void *user_data, int success) {
       (grpc_credentials_metadata_request *)user_data;
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)r->creds;
   GPR_ASSERT(success);
-  r->cb(r->user_data, c->md_store->entries,
-        c->md_store->num_entries, GRPC_CREDENTIALS_OK);
+  r->cb(r->user_data, c->md_store->entries, c->md_store->num_entries,
+        GRPC_CREDENTIALS_OK);
   grpc_credentials_metadata_request_destroy(r);
 }
 
 static void md_only_test_get_request_metadata(grpc_credentials *creds,
-                                             grpc_pollset *pollset,
-                                             const char *service_url,
-                                             grpc_credentials_metadata_cb cb,
-                                             void *user_data) {
+                                              grpc_pollset *pollset,
+                                              const char *service_url,
+                                              grpc_credentials_metadata_cb cb,
+                                              void *user_data) {
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)creds;
 
   if (c->is_async) {
@@ -854,10 +854,10 @@ static int access_token_has_request_metadata_only(
 }
 
 static void access_token_get_request_metadata(grpc_credentials *creds,
-                                             grpc_pollset *pollset,
-                                             const char *service_url,
-                                             grpc_credentials_metadata_cb cb,
-                                             void *user_data) {
+                                              grpc_pollset *pollset,
+                                              const char *service_url,
+                                              grpc_credentials_metadata_cb cb,
+                                              void *user_data) {
   grpc_access_token_credentials *c = (grpc_access_token_credentials *)creds;
   cb(user_data, c->access_token_md->entries, 1, GRPC_CREDENTIALS_OK);
 }
diff --git a/src/core/security/credentials.h b/src/core/security/credentials.h
index 04736525dc..29cd1ac87f 100644
--- a/src/core/security/credentials.h
+++ b/src/core/security/credentials.h
@@ -192,8 +192,9 @@ void grpc_flush_cached_google_default_credentials(void);
 
 /* Metadata-only credentials with the specified key and value where
    asynchronicity can be simulated for testing. */
-grpc_credentials *grpc_md_only_test_credentials_create(
-    const char *md_key, const char *md_value, int is_async);
+grpc_credentials *grpc_md_only_test_credentials_create(const char *md_key,
+                                                       const char *md_value,
+                                                       int is_async);
 
 /* Private constructor for jwt credentials from an already parsed json key.
    Takes ownership of the key. */
diff --git a/src/core/security/credentials_metadata.c b/src/core/security/credentials_metadata.c
index 22c786be56..b8a132f1ea 100644
--- a/src/core/security/credentials_metadata.c
+++ b/src/core/security/credentials_metadata.c
@@ -47,7 +47,8 @@ static void store_ensure_capacity(grpc_credentials_md_store *store) {
 
 grpc_credentials_md_store *grpc_credentials_md_store_create(
     size_t initial_capacity) {
-  grpc_credentials_md_store *store = gpr_malloc(sizeof(grpc_credentials_md_store));
+  grpc_credentials_md_store *store =
+      gpr_malloc(sizeof(grpc_credentials_md_store));
   memset(store, 0, sizeof(grpc_credentials_md_store));
   if (initial_capacity > 0) {
     store->entries = gpr_malloc(initial_capacity * sizeof(grpc_credentials_md));
@@ -98,4 +99,3 @@ void grpc_credentials_md_store_unref(grpc_credentials_md_store *store) {
     gpr_free(store);
   }
 }
-
diff --git a/src/core/security/google_default_credentials.c b/src/core/security/google_default_credentials.c
index d1f228665f..3631de867a 100644
--- a/src/core/security/google_default_credentials.c
+++ b/src/core/security/google_default_credentials.c
@@ -115,7 +115,7 @@ static int is_stack_running_on_compute_engine(void) {
   gpr_mu_lock(GRPC_POLLSET_MU(&detector.pollset));
   while (!detector.is_done) {
     grpc_pollset_worker worker;
-    grpc_pollset_work(&detector.pollset, &worker,
+    grpc_pollset_work(&detector.pollset, &worker, gpr_now(GPR_CLOCK_MONOTONIC),
                       gpr_inf_future(GPR_CLOCK_MONOTONIC));
   }
   gpr_mu_unlock(GRPC_POLLSET_MU(&detector.pollset));
@@ -203,8 +203,8 @@ end:
     /* Blend with default ssl credentials and add a global reference so that it
        can be cached and re-served. */
     grpc_credentials *ssl_creds = grpc_ssl_credentials_create(NULL, NULL);
-    default_credentials = grpc_credentials_ref(grpc_composite_credentials_create(
-        ssl_creds, result));
+    default_credentials = grpc_credentials_ref(
+        grpc_composite_credentials_create(ssl_creds, result));
     GPR_ASSERT(default_credentials != NULL);
     grpc_credentials_unref(ssl_creds);
     grpc_credentials_unref(result);
diff --git a/src/core/security/json_token.h b/src/core/security/json_token.h
index 091dfefb6e..7e06864ff3 100644
--- a/src/core/security/json_token.h
+++ b/src/core/security/json_token.h
@@ -115,4 +115,4 @@ grpc_auth_refresh_token grpc_auth_refresh_token_create_from_json(
 /* Destructs the object. */
 void grpc_auth_refresh_token_destruct(grpc_auth_refresh_token *refresh_token);
 
-#endif  /* GRPC_INTERNAL_CORE_SECURITY_JSON_TOKEN_H */
+#endif /* GRPC_INTERNAL_CORE_SECURITY_JSON_TOKEN_H */
diff --git a/src/core/security/jwt_verifier.h b/src/core/security/jwt_verifier.h
index 8077e24883..7a32debfcb 100644
--- a/src/core/security/jwt_verifier.h
+++ b/src/core/security/jwt_verifier.h
@@ -133,4 +133,3 @@ grpc_jwt_verifier_status grpc_jwt_claims_check(const grpc_jwt_claims *claims,
                                                const char *audience);
 
 #endif /* GRPC_INTERNAL_CORE_SECURITY_JWT_VERIFIER_H */
-
diff --git a/src/core/security/secure_endpoint.c b/src/core/security/secure_endpoint.c
index 95fbf71f3d..81b3e33cb2 100644
--- a/src/core/security/secure_endpoint.c
+++ b/src/core/security/secure_endpoint.c
@@ -332,7 +332,7 @@ static void endpoint_add_to_pollset(grpc_endpoint *secure_ep,
 }
 
 static void endpoint_add_to_pollset_set(grpc_endpoint *secure_ep,
-                                    grpc_pollset_set *pollset_set) {
+                                        grpc_pollset_set *pollset_set) {
   secure_endpoint *ep = (secure_endpoint *)secure_ep;
   grpc_endpoint_add_to_pollset_set(ep->wrapped_ep, pollset_set);
 }
diff --git a/src/core/security/secure_endpoint.h b/src/core/security/secure_endpoint.h
index 93c29b5111..c563bdd9c5 100644
--- a/src/core/security/secure_endpoint.h
+++ b/src/core/security/secure_endpoint.h
@@ -46,4 +46,4 @@ grpc_endpoint *grpc_secure_endpoint_create(
     struct tsi_frame_protector *protector, grpc_endpoint *to_wrap,
     gpr_slice *leftover_slices, size_t leftover_nslices);
 
-#endif  /* GRPC_INTERNAL_CORE_SECURITY_SECURE_ENDPOINT_H */
+#endif /* GRPC_INTERNAL_CORE_SECURITY_SECURE_ENDPOINT_H */
diff --git a/src/core/security/secure_transport_setup.h b/src/core/security/secure_transport_setup.h
index 29025f5236..d9b802556d 100644
--- a/src/core/security/secure_transport_setup.h
+++ b/src/core/security/secure_transport_setup.h
@@ -50,4 +50,4 @@ void grpc_setup_secure_transport(grpc_security_connector *connector,
                                  grpc_secure_transport_setup_done_cb cb,
                                  void *user_data);
 
-#endif  /* GRPC_INTERNAL_CORE_SECURITY_SECURE_TRANSPORT_SETUP_H */
+#endif /* GRPC_INTERNAL_CORE_SECURITY_SECURE_TRANSPORT_SETUP_H */
diff --git a/src/core/security/security_connector.c b/src/core/security/security_connector.c
index a354536dcd..ba9ac68c5f 100644
--- a/src/core/security/security_connector.c
+++ b/src/core/security/security_connector.c
@@ -575,6 +575,16 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
   if (!check_request_metadata_creds(request_metadata_creds)) {
     goto error;
   }
+  if (config->pem_root_certs == NULL) {
+    pem_root_certs_size = grpc_get_default_ssl_roots(&pem_root_certs);
+    if (pem_root_certs == NULL || pem_root_certs_size == 0) {
+      gpr_log(GPR_ERROR, "Could not get default pem root certs.");
+      goto error;
+    }
+  } else {
+    pem_root_certs = config->pem_root_certs;
+    pem_root_certs_size = config->pem_root_certs_size;
+  }
 
   c = gpr_malloc(sizeof(grpc_ssl_channel_security_connector));
   memset(c, 0, sizeof(grpc_ssl_channel_security_connector));
@@ -590,16 +600,6 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
   if (overridden_target_name != NULL) {
     c->overridden_target_name = gpr_strdup(overridden_target_name);
   }
-  if (config->pem_root_certs == NULL) {
-    pem_root_certs_size = grpc_get_default_ssl_roots(&pem_root_certs);
-    if (pem_root_certs == NULL || pem_root_certs_size == 0) {
-      gpr_log(GPR_ERROR, "Could not get default pem root certs.");
-      goto error;
-    }
-  } else {
-    pem_root_certs = config->pem_root_certs;
-    pem_root_certs_size = config->pem_root_certs_size;
-  }
   result = tsi_create_ssl_client_handshaker_factory(
       config->pem_private_key, config->pem_private_key_size,
       config->pem_cert_chain, config->pem_cert_chain_size, pem_root_certs,
diff --git a/src/core/security/security_context.c b/src/core/security/security_context.c
index 1ef0fc9255..c1b434f302 100644
--- a/src/core/security/security_context.c
+++ b/src/core/security/security_context.c
@@ -204,8 +204,7 @@ int grpc_auth_context_set_peer_identity_property_name(grpc_auth_context *ctx,
   return 1;
 }
 
-int grpc_auth_context_peer_is_authenticated(
-    const grpc_auth_context *ctx) {
+int grpc_auth_context_peer_is_authenticated(const grpc_auth_context *ctx) {
   return ctx->peer_identity_property_name == NULL ? 0 : 1;
 }
 
@@ -326,4 +325,3 @@ grpc_auth_metadata_processor *grpc_find_auth_metadata_processor_in_args(
   }
   return NULL;
 }
-
diff --git a/src/core/security/security_context.h b/src/core/security/security_context.h
index 7fcd438cf6..a9a0306410 100644
--- a/src/core/security/security_context.h
+++ b/src/core/security/security_context.h
@@ -112,5 +112,4 @@ grpc_auth_metadata_processor *grpc_auth_metadata_processor_from_arg(
 grpc_auth_metadata_processor *grpc_find_auth_metadata_processor_in_args(
     const grpc_channel_args *args);
 
-#endif  /* GRPC_INTERNAL_CORE_SECURITY_SECURITY_CONTEXT_H */
-
+#endif /* GRPC_INTERNAL_CORE_SECURITY_SECURITY_CONTEXT_H */
diff --git a/src/core/security/server_auth_filter.c b/src/core/security/server_auth_filter.c
index 2fc689caec..6e831431fa 100644
--- a/src/core/security/server_auth_filter.c
+++ b/src/core/security/server_auth_filter.c
@@ -104,24 +104,34 @@ static grpc_mdelem *remove_consumed_md(void *user_data, grpc_mdelem *md) {
   return md;
 }
 
-static void on_md_processing_done(void *user_data,
-                                  const grpc_metadata *consumed_md,
-                                  size_t num_consumed_md, int success) {
+static void on_md_processing_done(
+    void *user_data, const grpc_metadata *consumed_md, size_t num_consumed_md,
+    const grpc_metadata *response_md, size_t num_response_md,
+    grpc_status_code status, const char *error_details) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
 
-  if (success) {
+  /* TODO(jboeuf): Implement support for response_md. */
+  if (response_md != NULL && num_response_md > 0) {
+    gpr_log(GPR_INFO,
+            "response_md in auth metadata processing not supported for now. "
+            "Ignoring...");
+  }
+
+  if (status == GRPC_STATUS_OK) {
     calld->consumed_md = consumed_md;
     calld->num_consumed_md = num_consumed_md;
     grpc_metadata_batch_filter(&calld->md_op->data.metadata, remove_consumed_md,
                                elem);
-    calld->on_done_recv->cb(calld->on_done_recv->cb_arg, success);
+    calld->on_done_recv->cb(calld->on_done_recv->cb_arg, 1);
   } else {
-    gpr_slice message = gpr_slice_from_copied_string(
-        "Authentication metadata processing failed.");
+    gpr_slice message;
+    error_details = error_details != NULL
+                    ? error_details
+                    : "Authentication metadata processing failed.";
+    message = gpr_slice_from_copied_string(error_details);
     grpc_sopb_reset(calld->recv_ops);
-    grpc_transport_stream_op_add_close(&calld->transport_op,
-                                       GRPC_STATUS_UNAUTHENTICATED, &message);
+    grpc_transport_stream_op_add_close(&calld->transport_op, status, &message);
     grpc_call_next_op(elem, &calld->transport_op);
   }
 }
@@ -212,8 +222,7 @@ static void init_call_elem(grpc_call_element *elem,
 }
 
 /* Destructor for call_data */
-static void destroy_call_elem(grpc_call_element *elem) {
-}
+static void destroy_call_elem(grpc_call_element *elem) {}
 
 /* Constructor for channel_data */
 static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
diff --git a/src/core/statistics/census_interface.h b/src/core/statistics/census_interface.h
index eb4349c311..ac1ff24866 100644
--- a/src/core/statistics/census_interface.h
+++ b/src/core/statistics/census_interface.h
@@ -73,4 +73,4 @@ census_op_id census_tracing_start_op(void);
 /* Ends tracing. Calling this function will invalidate the input op_id. */
 void census_tracing_end_op(census_op_id op_id);
 
-#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_INTERFACE_H */
+#endif /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_INTERFACE_H */
diff --git a/src/core/statistics/census_log.h b/src/core/statistics/census_log.h
index 06869b7a33..60b6d597df 100644
--- a/src/core/statistics/census_log.h
+++ b/src/core/statistics/census_log.h
@@ -88,4 +88,4 @@ size_t census_log_remaining_space(void);
    out-of-space. */
 int census_log_out_of_space_count(void);
 
-#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_LOG_H */
+#endif /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_LOG_H */
diff --git a/src/core/statistics/census_rpc_stats.c b/src/core/statistics/census_rpc_stats.c
index 3e571b1143..b836987cf0 100644
--- a/src/core/statistics/census_rpc_stats.c
+++ b/src/core/statistics/census_rpc_stats.c
@@ -85,8 +85,8 @@ static void delete_key(void* key) { gpr_free(key); }
 
 static const census_ht_option ht_opt = {
     CENSUS_HT_POINTER /* key type */, 1999 /* n_of_buckets */,
-    simple_hash /* hash function */, cmp_str_keys /* key comparator */,
-    delete_stats /* data deleter */, delete_key /* key deleter */
+    simple_hash /* hash function */,  cmp_str_keys /* key comparator */,
+    delete_stats /* data deleter */,  delete_key /* key deleter */
 };
 
 static void init_rpc_stats(void* stats) {
diff --git a/src/core/statistics/census_rpc_stats.h b/src/core/statistics/census_rpc_stats.h
index 9336dce1f8..aec31c1971 100644
--- a/src/core/statistics/census_rpc_stats.h
+++ b/src/core/statistics/census_rpc_stats.h
@@ -98,4 +98,4 @@ void census_stats_store_shutdown(void);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_RPC_STATS_H */
+#endif /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_RPC_STATS_H */
diff --git a/src/core/statistics/census_tracing.c b/src/core/statistics/census_tracing.c
index 3036ba5407..f2a09dc06e 100644
--- a/src/core/statistics/census_tracing.c
+++ b/src/core/statistics/census_tracing.c
@@ -60,8 +60,11 @@ static void delete_trace_obj(void* obj) {
 }
 
 static const census_ht_option ht_opt = {
-    CENSUS_HT_UINT64 /* key type*/, 571 /* n_of_buckets */, NULL /* hash */,
-    NULL /* compare_keys */, delete_trace_obj /* delete data */,
+    CENSUS_HT_UINT64 /* key type*/,
+    571 /* n_of_buckets */,
+    NULL /* hash */,
+    NULL /* compare_keys */,
+    delete_trace_obj /* delete data */,
     NULL /* delete key */
 };
 
diff --git a/src/core/statistics/census_tracing.h b/src/core/statistics/census_tracing.h
index a4494b510c..08305c2469 100644
--- a/src/core/statistics/census_tracing.h
+++ b/src/core/statistics/census_tracing.h
@@ -93,4 +93,4 @@ census_trace_obj** census_get_active_ops(int* num_active_ops);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_TRACING_H */
+#endif /* GRPC_INTERNAL_CORE_STATISTICS_CENSUS_TRACING_H */
diff --git a/src/core/statistics/hash_table.h b/src/core/statistics/hash_table.h
index 7bcb4bcd9b..b7f8e11af4 100644
--- a/src/core/statistics/hash_table.h
+++ b/src/core/statistics/hash_table.h
@@ -128,4 +128,4 @@ typedef void (*census_ht_itr_cb)(census_ht_key key, const void* val_ptr,
    should not invalidate data entries. */
 gpr_uint64 census_ht_for_all(const census_ht* ht, census_ht_itr_cb);
 
-#endif  /* GRPC_INTERNAL_CORE_STATISTICS_HASH_TABLE_H */
+#endif /* GRPC_INTERNAL_CORE_STATISTICS_HASH_TABLE_H */
diff --git a/src/core/support/cpu_iphone.c b/src/core/support/cpu_iphone.c
index d412a6d7ee..82b49b47bc 100644
--- a/src/core/support/cpu_iphone.c
+++ b/src/core/support/cpu_iphone.c
@@ -36,9 +36,7 @@
 #ifdef GPR_CPU_IPHONE
 
 /* Probably 2 instead of 1, but see comment on gpr_cpu_current_cpu. */
-unsigned gpr_cpu_num_cores(void) {
-  return 1;
-}
+unsigned gpr_cpu_num_cores(void) { return 1; }
 
 /* Most code that's using this is using it to shard across work queues. So
    unless profiling shows it's a problem or there appears a way to detect the
@@ -46,8 +44,6 @@ unsigned gpr_cpu_num_cores(void) {
    Note that the interface in cpu.h lets gpr_cpu_num_cores return 0, but doing
    it makes it impossible for gpr_cpu_current_cpu to satisfy its stated range,
    and some code might be relying on it. */
-unsigned gpr_cpu_current_cpu(void) {
-  return 0;
-}
+unsigned gpr_cpu_current_cpu(void) { return 0; }
 
 #endif /* GPR_CPU_IPHONE */
diff --git a/src/core/support/cpu_linux.c b/src/core/support/cpu_linux.c
index 282d4daab1..7af6a8f009 100644
--- a/src/core/support/cpu_linux.c
+++ b/src/core/support/cpu_linux.c
@@ -33,7 +33,7 @@
 
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
-#endif  /* _GNU_SOURCE */
+#endif /* _GNU_SOURCE */
 
 #include <grpc/support/port_platform.h>
 
diff --git a/src/core/support/env.h b/src/core/support/env.h
index 4f2e394d14..24172d8673 100644
--- a/src/core/support/env.h
+++ b/src/core/support/env.h
@@ -57,4 +57,4 @@ void gpr_setenv(const char *name, const char *value);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_SUPPORT_ENV_H */
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_ENV_H */
diff --git a/src/core/support/file.h b/src/core/support/file.h
index 1dafe390e3..d8b7cea44f 100644
--- a/src/core/support/file.h
+++ b/src/core/support/file.h
@@ -60,4 +60,4 @@ FILE *gpr_tmpfile(const char *prefix, char **tmp_filename);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_SUPPORT_FILE_H */
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_FILE_H */
diff --git a/src/core/support/histogram.c b/src/core/support/histogram.c
index 9029703891..78dbf98684 100644
--- a/src/core/support/histogram.c
+++ b/src/core/support/histogram.c
@@ -191,15 +191,18 @@ static double threshold_for_count_below(gpr_histogram *h, double count_below) {
         break;
       }
     }
-    return (bucket_start(h, (double)lower_idx) + bucket_start(h, (double)upper_idx)) / 2.0;
+    return (bucket_start(h, (double)lower_idx) +
+            bucket_start(h, (double)upper_idx)) /
+           2.0;
   } else {
     /* treat values as uniform throughout the bucket, and find where this value
        should lie */
     lower_bound = bucket_start(h, (double)lower_idx);
     upper_bound = bucket_start(h, (double)(lower_idx + 1));
-    return GPR_CLAMP(upper_bound - (upper_bound - lower_bound) *
-                                       (count_so_far - count_below) /
-                                       h->buckets[lower_idx],
+    return GPR_CLAMP(upper_bound -
+                         (upper_bound - lower_bound) *
+                             (count_so_far - count_below) /
+                             h->buckets[lower_idx],
                      h->min_seen, h->max_seen);
   }
 }
diff --git a/src/core/support/log_linux.c b/src/core/support/log_linux.c
index 5ac36e7b95..02f64d8b7e 100644
--- a/src/core/support/log_linux.c
+++ b/src/core/support/log_linux.c
@@ -93,8 +93,8 @@ void gpr_default_log(gpr_log_func_args *args) {
   }
 
   gpr_asprintf(&prefix, "%s%s.%09d %7tu %s:%d]",
-          gpr_log_severity_string(args->severity), time_buffer,
-          (int)(now.tv_nsec), gettid(), display_file, args->line);
+               gpr_log_severity_string(args->severity), time_buffer,
+               (int)(now.tv_nsec), gettid(), display_file, args->line);
 
   fprintf(stderr, "%-60s %s\n", prefix, args->message);
   gpr_free(prefix);
diff --git a/src/core/support/murmur_hash.h b/src/core/support/murmur_hash.h
index 85ab2fe4bf..343fcb99f7 100644
--- a/src/core/support/murmur_hash.h
+++ b/src/core/support/murmur_hash.h
@@ -41,4 +41,4 @@
 /* compute the hash of key (length len) */
 gpr_uint32 gpr_murmur_hash3(const void *key, size_t len, gpr_uint32 seed);
 
-#endif  /* GRPC_INTERNAL_CORE_SUPPORT_MURMUR_HASH_H */
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_MURMUR_HASH_H */
diff --git a/src/core/support/slice.c b/src/core/support/slice.c
index e4196a48c6..53024e88f1 100644
--- a/src/core/support/slice.c
+++ b/src/core/support/slice.c
@@ -284,7 +284,8 @@ gpr_slice gpr_slice_split_head(gpr_slice *source, size_t split) {
     head.refcount = NULL;
     head.data.inlined.length = (gpr_uint8)split;
     memcpy(head.data.inlined.bytes, source->data.inlined.bytes, split);
-    source->data.inlined.length = (gpr_uint8)(source->data.inlined.length - split);
+    source->data.inlined.length =
+        (gpr_uint8)(source->data.inlined.length - split);
     memmove(source->data.inlined.bytes, source->data.inlined.bytes + split,
             source->data.inlined.length);
   } else if (split < sizeof(head.data.inlined.bytes)) {
diff --git a/src/core/support/slice_buffer.c b/src/core/support/slice_buffer.c
index 6e6c72a2bf..987d5cb9b5 100644
--- a/src/core/support/slice_buffer.c
+++ b/src/core/support/slice_buffer.c
@@ -116,7 +116,8 @@ void gpr_slice_buffer_add(gpr_slice_buffer *sb, gpr_slice s) {
           GPR_SLICE_INLINED_SIZE) {
         memcpy(back->data.inlined.bytes + back->data.inlined.length,
                s.data.inlined.bytes, s.data.inlined.length);
-        back->data.inlined.length = (gpr_uint8)(back->data.inlined.length + s.data.inlined.length);
+        back->data.inlined.length =
+            (gpr_uint8)(back->data.inlined.length + s.data.inlined.length);
       } else {
         size_t cp1 = GPR_SLICE_INLINED_SIZE - back->data.inlined.length;
         memcpy(back->data.inlined.bytes + back->data.inlined.length,
diff --git a/src/core/support/stack_lockfree.c b/src/core/support/stack_lockfree.c
index bc741f8c70..27ecf62280 100644
--- a/src/core/support/stack_lockfree.c
+++ b/src/core/support/stack_lockfree.c
@@ -67,7 +67,7 @@ typedef union lockfree_node {
 #define ENTRY_ALIGNMENT_BITS 3 /* make sure that entries aligned to 8-bytes */
 #define INVALID_ENTRY_INDEX                        \
   ((1 << 16) - 1) /* reserve this entry as invalid \
-                       */
+                        */
 
 struct gpr_stack_lockfree {
   lockfree_node *entries;
@@ -75,7 +75,7 @@ struct gpr_stack_lockfree {
 
 #ifndef NDEBUG
   /* Bitmap of pushed entries to check for double-push or pop */
-  gpr_atm pushed[(INVALID_ENTRY_INDEX+1)/(8*sizeof(gpr_atm))];
+  gpr_atm pushed[(INVALID_ENTRY_INDEX + 1) / (8 * sizeof(gpr_atm))];
 #endif
 };
 
@@ -123,13 +123,13 @@ int gpr_stack_lockfree_push(gpr_stack_lockfree *stack, int entry) {
 #ifndef NDEBUG
   /* Check for double push */
   {
-    int pushed_index = entry / (8*sizeof(gpr_atm));
-    int pushed_bit = entry % (8*sizeof(gpr_atm));
+    int pushed_index = entry / (8 * sizeof(gpr_atm));
+    int pushed_bit = entry % (8 * sizeof(gpr_atm));
     gpr_atm old_val;
 
     old_val = gpr_atm_no_barrier_fetch_add(&stack->pushed[pushed_index],
-					   (gpr_atm)(1UL << pushed_bit));
-    GPR_ASSERT((old_val & (1UL<<pushed_bit)) == 0);
+                                           (gpr_atm)(1UL << pushed_bit));
+    GPR_ASSERT((old_val & (1UL << pushed_bit)) == 0);
   }
 #endif
 
@@ -161,13 +161,13 @@ int gpr_stack_lockfree_pop(gpr_stack_lockfree *stack) {
 #ifndef NDEBUG
   /* Check for valid pop */
   {
-    int pushed_index = head.contents.index / (8*sizeof(gpr_atm));
-    int pushed_bit = head.contents.index % (8*sizeof(gpr_atm));
+    int pushed_index = head.contents.index / (8 * sizeof(gpr_atm));
+    int pushed_bit = head.contents.index % (8 * sizeof(gpr_atm));
     gpr_atm old_val;
 
     old_val = gpr_atm_no_barrier_fetch_add(&stack->pushed[pushed_index],
-					   -(gpr_atm)(1UL << pushed_bit));
-    GPR_ASSERT((old_val & (1UL<<pushed_bit)) != 0);
+                                           -(gpr_atm)(1UL << pushed_bit));
+    GPR_ASSERT((old_val & (1UL << pushed_bit)) != 0);
   }
 #endif
 
diff --git a/src/core/support/string.c b/src/core/support/string.c
index 9babbd910a..af0389ea83 100644
--- a/src/core/support/string.c
+++ b/src/core/support/string.c
@@ -125,7 +125,6 @@ char *gpr_dump_slice(gpr_slice s, gpr_uint32 flags) {
                   flags);
 }
 
-
 int gpr_parse_bytes_to_uint32(const char *buf, size_t len, gpr_uint32 *result) {
   gpr_uint32 out = 0;
   gpr_uint32 new;
@@ -187,9 +186,9 @@ char *gpr_strjoin_sep(const char **strs, size_t nstrs, const char *sep,
   for (i = 0; i < nstrs; i++) {
     out_length += strlen(strs[i]);
   }
-  out_length += 1;  /* null terminator */
+  out_length += 1; /* null terminator */
   if (nstrs > 0) {
-    out_length += sep_len * (nstrs - 1);  /* separators */
+    out_length += sep_len * (nstrs - 1); /* separators */
   }
   out = gpr_malloc(out_length);
   out_length = 0;
@@ -214,10 +213,8 @@ char *gpr_strjoin_sep(const char **strs, size_t nstrs, const char *sep,
  * str.
  *
  * Returns 1 and updates \a begin and \a end. Returns 0 otherwise. */
-static int slice_find_separator_offset(const gpr_slice str,
-                                       const char *sep,
-                                       const size_t read_offset,
-                                       size_t *begin,
+static int slice_find_separator_offset(const gpr_slice str, const char *sep,
+                                       const size_t read_offset, size_t *begin,
                                        size_t *end) {
   size_t i;
   const gpr_uint8 *str_ptr = GPR_SLICE_START_PTR(str) + read_offset;
@@ -255,9 +252,7 @@ void gpr_slice_split(gpr_slice str, const char *sep, gpr_slice_buffer *dst) {
   }
 }
 
-void gpr_strvec_init(gpr_strvec *sv) {
-  memset(sv, 0, sizeof(*sv));
-}
+void gpr_strvec_init(gpr_strvec *sv) { memset(sv, 0, sizeof(*sv)); }
 
 void gpr_strvec_destroy(gpr_strvec *sv) {
   size_t i;
@@ -270,11 +265,11 @@ void gpr_strvec_destroy(gpr_strvec *sv) {
 void gpr_strvec_add(gpr_strvec *sv, char *str) {
   if (sv->count == sv->capacity) {
     sv->capacity = GPR_MAX(sv->capacity + 8, sv->capacity * 2);
-    sv->strs = gpr_realloc(sv->strs, sizeof(char*) * sv->capacity);
+    sv->strs = gpr_realloc(sv->strs, sizeof(char *) * sv->capacity);
   }
   sv->strs[sv->count++] = str;
 }
 
 char *gpr_strvec_flatten(gpr_strvec *sv, size_t *final_length) {
-  return gpr_strjoin((const char**)sv->strs, sv->count, final_length);
+  return gpr_strjoin((const char **)sv->strs, sv->count, final_length);
 }
diff --git a/src/core/support/string.h b/src/core/support/string.h
index 3ac4abeef8..a28e00fd3e 100644
--- a/src/core/support/string.h
+++ b/src/core/support/string.h
@@ -47,7 +47,7 @@ extern "C" {
 /* String utility functions */
 
 /* Flags for gpr_dump function. */
-#define GPR_DUMP_HEX   0x00000001
+#define GPR_DUMP_HEX 0x00000001
 #define GPR_DUMP_ASCII 0x00000002
 
 /* Converts array buf, of length len, into a C string  according to the flags.
@@ -108,4 +108,4 @@ char *gpr_strvec_flatten(gpr_strvec *strs, size_t *total_length);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_SUPPORT_STRING_H */
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_STRING_H */
diff --git a/src/core/support/string_win32.c b/src/core/support/string_win32.c
index 27b9f3637a..8ffb0a225e 100644
--- a/src/core/support/string_win32.c
+++ b/src/core/support/string_win32.c
@@ -99,13 +99,9 @@ LPSTR gpr_tchar_to_char(LPCTSTR input) {
   return ret;
 }
 #else
-char *gpr_tchar_to_char(LPTSTR input) {
-  return gpr_strdup(input);
-}
+char *gpr_tchar_to_char(LPTSTR input) { return gpr_strdup(input); }
 
-char *gpr_char_to_tchar(LPTSTR input) {
-  return gpr_strdup(input);
-}
+char *gpr_char_to_tchar(LPTSTR input) { return gpr_strdup(input); }
 #endif
 
 #endif /* GPR_WIN32 */
diff --git a/src/core/support/string_win32.h b/src/core/support/string_win32.h
index 1260aa55c1..e3043656fb 100644
--- a/src/core/support/string_win32.h
+++ b/src/core/support/string_win32.h
@@ -42,6 +42,6 @@
 LPTSTR gpr_char_to_tchar(LPCSTR input);
 LPSTR gpr_tchar_to_char(LPCTSTR input);
 
-#endif  /* GPR_WIN32 */
+#endif /* GPR_WIN32 */
 
-#endif  /* GRPC_INTERNAL_CORE_SUPPORT_STRING_WIN32_H */
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_STRING_WIN32_H */
diff --git a/src/core/support/sync_posix.c b/src/core/support/sync_posix.c
index 61572b9a8e..6f078cd4bb 100644
--- a/src/core/support/sync_posix.c
+++ b/src/core/support/sync_posix.c
@@ -63,7 +63,8 @@ void gpr_cv_destroy(gpr_cv *cv) { GPR_ASSERT(pthread_cond_destroy(cv) == 0); }
 
 int gpr_cv_wait(gpr_cv *cv, gpr_mu *mu, gpr_timespec abs_deadline) {
   int err = 0;
-  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) == 0) {
+  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) ==
+      0) {
     err = pthread_cond_wait(cv, mu);
   } else {
     struct timespec abs_deadline_ts;
diff --git a/src/core/support/sync_win32.c b/src/core/support/sync_win32.c
index 54f84a46ac..df23492171 100644
--- a/src/core/support/sync_win32.c
+++ b/src/core/support/sync_win32.c
@@ -83,7 +83,8 @@ int gpr_cv_wait(gpr_cv *cv, gpr_mu *mu, gpr_timespec abs_deadline) {
   int timeout = 0;
   DWORD timeout_max_ms;
   mu->locked = 0;
-  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) == 0) {
+  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) ==
+      0) {
     SleepConditionVariableCS(cv, &mu->cs, INFINITE);
   } else {
     gpr_timespec now = gpr_now(abs_deadline.clock_type);
diff --git a/src/core/support/thd.c b/src/core/support/thd.c
index ec308f3119..32c0db5b66 100644
--- a/src/core/support/thd.c
+++ b/src/core/support/thd.c
@@ -37,9 +37,7 @@
 
 #include <grpc/support/thd.h>
 
-enum {
-  GPR_THD_JOINABLE = 1
-};
+enum { GPR_THD_JOINABLE = 1 };
 
 gpr_thd_options gpr_thd_options_default(void) {
   gpr_thd_options options;
diff --git a/src/core/support/thd_internal.h b/src/core/support/thd_internal.h
index 4683c37742..1508c4691f 100644
--- a/src/core/support/thd_internal.h
+++ b/src/core/support/thd_internal.h
@@ -36,4 +36,4 @@
 
 /* Internal interfaces between modules within the gpr support library.  */
 
-#endif  /* GRPC_INTERNAL_CORE_SUPPORT_THD_INTERNAL_H */
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_THD_INTERNAL_H */
diff --git a/src/core/support/thd_posix.c b/src/core/support/thd_posix.c
index fa4eb50556..c36d94d044 100644
--- a/src/core/support/thd_posix.c
+++ b/src/core/support/thd_posix.c
@@ -69,9 +69,11 @@ int gpr_thd_new(gpr_thd_id *t, void (*thd_body)(void *arg), void *arg,
 
   GPR_ASSERT(pthread_attr_init(&attr) == 0);
   if (gpr_thd_options_is_detached(options)) {
-    GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0);
+    GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) ==
+               0);
   } else {
-    GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE) == 0);
+    GPR_ASSERT(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE) ==
+               0);
   }
   thread_started = (pthread_create(&p, &attr, &thread_body, a) == 0);
   GPR_ASSERT(pthread_attr_destroy(&attr) == 0);
@@ -82,12 +84,8 @@ int gpr_thd_new(gpr_thd_id *t, void (*thd_body)(void *arg), void *arg,
   return thread_started;
 }
 
-gpr_thd_id gpr_thd_currentid(void) {
-  return (gpr_thd_id)pthread_self();
-}
+gpr_thd_id gpr_thd_currentid(void) { return (gpr_thd_id)pthread_self(); }
 
-void gpr_thd_join(gpr_thd_id t) {
-  pthread_join((pthread_t)t, NULL);
-}
+void gpr_thd_join(gpr_thd_id t) { pthread_join((pthread_t)t, NULL); }
 
 #endif /* GPR_POSIX_SYNC */
diff --git a/src/core/support/thd_win32.c b/src/core/support/thd_win32.c
index 4fa3907444..a9db180c1b 100644
--- a/src/core/support/thd_win32.c
+++ b/src/core/support/thd_win32.c
@@ -105,9 +105,7 @@ int gpr_thd_new(gpr_thd_id *t, void (*thd_body)(void *arg), void *arg,
   return handle != NULL;
 }
 
-gpr_thd_id gpr_thd_currentid(void) {
-  return (gpr_thd_id)g_thd_info;
-}
+gpr_thd_id gpr_thd_currentid(void) { return (gpr_thd_id)g_thd_info; }
 
 void gpr_thd_join(gpr_thd_id t) {
   struct thd_info *info = (struct thd_info *)t;
diff --git a/src/core/support/time.c b/src/core/support/time.c
index b523ae01cc..929adac918 100644
--- a/src/core/support/time.c
+++ b/src/core/support/time.c
@@ -315,5 +315,6 @@ gpr_timespec gpr_convert_clock_type(gpr_timespec t, gpr_clock_type clock_type) {
     return gpr_time_add(gpr_now(clock_type), t);
   }
 
-  return gpr_time_add(gpr_now(clock_type), gpr_time_sub(t, gpr_now(t.clock_type)));
+  return gpr_time_add(gpr_now(clock_type),
+                      gpr_time_sub(t, gpr_now(t.clock_type)));
 }
diff --git a/src/core/support/time_posix.c b/src/core/support/time_posix.c
index 841485c4b4..a274400243 100644
--- a/src/core/support/time_posix.c
+++ b/src/core/support/time_posix.c
@@ -32,6 +32,7 @@
  */
 
 #include <grpc/support/port_platform.h>
+#include <src/core/support/time_precise.h>
 
 #ifdef GPR_POSIX_TIME
 
@@ -66,8 +67,14 @@ void gpr_time_init(void) {}
 gpr_timespec gpr_now(gpr_clock_type clock) {
   struct timespec now;
   GPR_ASSERT(clock != GPR_TIMESPAN);
-  clock_gettime(clockid_for_gpr_clock[clock], &now);
-  return gpr_from_timespec(now, clock);
+  if (clock == GPR_CLOCK_PRECISE) {
+    gpr_timespec ret;
+    gpr_precise_clock_now(&ret);
+    return ret;
+  } else {
+    clock_gettime(clockid_for_gpr_clock[clock], &now);
+    return gpr_from_timespec(now, clock);
+  }
 }
 #else
 /* For some reason Apple's OSes haven't implemented clock_gettime. */
@@ -104,6 +111,9 @@ gpr_timespec gpr_now(gpr_clock_type clock) {
       now.tv_sec = now_dbl * 1e-9;
       now.tv_nsec = now_dbl - now.tv_sec * 1e9;
       break;
+    case GPR_CLOCK_PRECISE:
+      gpr_precise_clock_now(&now);
+      break;
     case GPR_TIMESPAN:
       abort();
   }
diff --git a/src/core/profiling/timers_preciseclock.h b/src/core/support/time_precise.h
index 5c251b47e6..574ebb8448 100644
--- a/src/core/profiling/timers_preciseclock.h
+++ b/src/core/support/time_precise.h
@@ -31,65 +31,63 @@
  *
  */
 
-#ifndef GRPC_CORE_PROFILING_TIMERS_PRECISECLOCK_H
-#define GRPC_CORE_PROFILING_TIMERS_PRECISECLOCK_H
+#ifndef GRPC_CORE_SUPPORT_TIME_PRECISE_H_
+#define GRPC_CORE_SUPPORT_TIME_PRECISE_H_
 
 #include <grpc/support/sync.h>
 #include <grpc/support/time.h>
 #include <stdio.h>
 
 #ifdef GRPC_TIMERS_RDTSC
-typedef long long int grpc_precise_clock;
 #if defined(__i386__)
-static void grpc_precise_clock_now(grpc_precise_clock *clk) {
-  grpc_precise_clock ret;
+static void gpr_get_cycle_counter(long long int *clk) {
+  long long int ret;
   __asm__ volatile("rdtsc" : "=A"(ret));
   *clk = ret;
 }
 
 // ----------------------------------------------------------------
 #elif defined(__x86_64__) || defined(__amd64__)
-static void grpc_precise_clock_now(grpc_precise_clock *clk) {
+static void gpr_get_cycle_counter(long long int *clk) {
   unsigned long long low, high;
   __asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
   *clk = (high << 32) | low;
 }
 #endif
+
 static gpr_once precise_clock_init = GPR_ONCE_INIT;
-static double cycles_per_second = 0.0;
-static void grpc_precise_clock_init() {
+static long long cycles_per_second = 0;
+static void gpr_precise_clock_init() {
   time_t start = time(NULL);
-  grpc_precise_clock start_time;
-  grpc_precise_clock end_time;
+  gpr_precise_clock start_cycle;
+  gpr_precise_clock end_cycle;
   while (time(NULL) == start)
     ;
-  grpc_precise_clock_now(&start_time);
+  gpr_get_cycle_counter(&start_cycle);
   while (time(NULL) == start + 1)
     ;
-  grpc_precise_clock_now(&end_time);
-  cycles_per_second = end_time - start_time;
+  gpr_get_cycle_counter(&end_cycle);
+  cycles_per_second = end_cycle - start_cycle;
 }
+
 static double grpc_precise_clock_scaling_factor() {
   gpr_once_init(&precise_clock_init, grpc_precise_clock_init);
   return 1e6 / cycles_per_second;
 }
-#define GRPC_PRECISE_CLOCK_FORMAT "%f"
-#define GRPC_PRECISE_CLOCK_PRINTF_ARGS(clk) \
-  (*(clk)*grpc_precise_clock_scaling_factor())
-#else
-typedef struct grpc_precise_clock grpc_precise_clock;
-struct grpc_precise_clock {
-  gpr_timespec clock;
-};
-static void grpc_precise_clock_now(grpc_precise_clock* clk) {
-  clk->clock = gpr_now(GPR_CLOCK_REALTIME);
+
+static void gpr_precise_clock_now(gpr_timespec *clk) {
+  long long int counter;
+  gpr_get_cycle_counter(&counter);
+  clk->clock = GPR_CLOCK_REALTIME;
+  clk->tv_sec = counter / cycles_per_second;
+  clk->tv_nsec = counter % cycles_per_second;
 }
-#define GRPC_PRECISE_CLOCK_FORMAT "%ld.%09d"
-#define GRPC_PRECISE_CLOCK_PRINTF_ARGS(clk) \
-  (clk)->clock.tv_sec, (clk)->clock.tv_nsec
-static void grpc_precise_clock_print(const grpc_precise_clock* clk, FILE* fp) {
-  fprintf(fp, "%ld.%09d", clk->clock.tv_sec, clk->clock.tv_nsec);
+
+#else /* GRPC_TIMERS_RDTSC */
+static void gpr_precise_clock_now(gpr_timespec *clk) {
+  *clk = gpr_now(GPR_CLOCK_REALTIME);
+  clk->clock_type = GPR_CLOCK_PRECISE;
 }
 #endif /* GRPC_TIMERS_RDTSC */
 
-#endif /* GRPC_CORE_PROFILING_TIMERS_PRECISECLOCK_H */
+#endif /* GRPC_CORE_SUPPORT_TIME_PRECISE_ */
diff --git a/src/core/support/time_win32.c b/src/core/support/time_win32.c
index 7f64c80e27..f794855429 100644
--- a/src/core/support/time_win32.c
+++ b/src/core/support/time_win32.c
@@ -38,6 +38,7 @@
 #ifdef GPR_WIN32
 
 #include <grpc/support/time.h>
+#include <src/core/support/time_precise.h>
 #include <sys/timeb.h>
 
 static LARGE_INTEGER g_start_time;
@@ -68,6 +69,9 @@ gpr_timespec gpr_now(gpr_clock_type clock) {
       now_tv.tv_sec = (time_t)now_dbl;
       now_tv.tv_nsec = (int)((now_dbl - (double)now_tv.tv_sec) * 1e9);
       break;
+    case GPR_CLOCK_PRECISE:
+      gpr_precise_clock_now(&now_tv);
+      break;
   }
   return now_tv;
 }
diff --git a/src/core/support/tls_pthread.c b/src/core/support/tls_pthread.c
index f2e76a553f..2d28226fc4 100644
--- a/src/core/support/tls_pthread.c
+++ b/src/core/support/tls_pthread.c
@@ -38,7 +38,7 @@
 #include <grpc/support/tls.h>
 
 gpr_intptr gpr_tls_set(struct gpr_pthread_thread_local *tls, gpr_intptr value) {
-  GPR_ASSERT(0 == pthread_setspecific(tls->key, (void*)value));
+  GPR_ASSERT(0 == pthread_setspecific(tls->key, (void *)value));
   return value;
 }
 
diff --git a/src/core/surface/byte_buffer_queue.h b/src/core/surface/byte_buffer_queue.h
index f01958984f..2c3b22d24e 100644
--- a/src/core/surface/byte_buffer_queue.h
+++ b/src/core/surface/byte_buffer_queue.h
@@ -59,4 +59,4 @@ int grpc_bbq_empty(grpc_byte_buffer_queue *q);
 void grpc_bbq_push(grpc_byte_buffer_queue *q, grpc_byte_buffer *bb);
 size_t grpc_bbq_bytes(grpc_byte_buffer_queue *q);
 
-#endif  /* GRPC_INTERNAL_CORE_SURFACE_BYTE_BUFFER_QUEUE_H */
+#endif /* GRPC_INTERNAL_CORE_SURFACE_BYTE_BUFFER_QUEUE_H */
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 6a1a6cbf30..4426bbbce9 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -39,6 +39,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
 
 #include "src/core/channel/channel_stack.h"
 #include "src/core/iomgr/alarm.h"
@@ -242,6 +243,9 @@ struct grpc_call {
   /* Compression algorithm for the call */
   grpc_compression_algorithm compression_algorithm;
 
+  /* Supported encodings (compression algorithms), a bitset */
+  gpr_uint32 encodings_accepted_by_peer;
+
   /* Contexts for various subsystems (security, tracing, ...). */
   grpc_call_context_element context[GRPC_CONTEXT_COUNT];
 
@@ -272,7 +276,8 @@ struct grpc_call {
   /** completion events - for completion queue use */
   grpc_cq_completion completions[MAX_CONCURRENT_COMPLETIONS];
 
-  /** siblings: children of the same parent form a list, and this list is protected under
+  /** siblings: children of the same parent form a list, and this list is
+     protected under
       parent->mu */
   grpc_call *sibling_next;
   grpc_call *sibling_prev;
@@ -394,7 +399,8 @@ grpc_call *grpc_call_create(grpc_channel *channel, grpc_call *parent_call,
     } else {
       call->sibling_next = parent_call->first_child;
       call->sibling_prev = parent_call->first_child->sibling_prev;
-      call->sibling_next->sibling_prev = call->sibling_prev->sibling_next = call;
+      call->sibling_next->sibling_prev = call->sibling_prev->sibling_next =
+          call;
     }
 
     gpr_mu_unlock(&parent_call->mu);
@@ -532,6 +538,45 @@ grpc_compression_algorithm grpc_call_get_compression_algorithm(
   return call->compression_algorithm;
 }
 
+static void set_encodings_accepted_by_peer(
+    grpc_call *call, const gpr_slice accept_encoding_slice) {
+  size_t i;
+  grpc_compression_algorithm algorithm;
+  gpr_slice_buffer accept_encoding_parts;
+
+  gpr_slice_buffer_init(&accept_encoding_parts);
+  gpr_slice_split(accept_encoding_slice, ", ", &accept_encoding_parts);
+
+  /* No need to zero call->encodings_accepted_by_peer: grpc_call_create already
+   * zeroes the whole grpc_call */
+  /* Always support no compression */
+  GPR_BITSET(&call->encodings_accepted_by_peer, GRPC_COMPRESS_NONE);
+  for (i = 0; i < accept_encoding_parts.count; i++) {
+    const gpr_slice *accept_encoding_entry_slice =
+        &accept_encoding_parts.slices[i];
+    if (grpc_compression_algorithm_parse(
+            (const char *)GPR_SLICE_START_PTR(*accept_encoding_entry_slice),
+            GPR_SLICE_LENGTH(*accept_encoding_entry_slice), &algorithm)) {
+      GPR_BITSET(&call->encodings_accepted_by_peer, algorithm);
+    } else {
+      char *accept_encoding_entry_str =
+          gpr_dump_slice(*accept_encoding_entry_slice, GPR_DUMP_ASCII);
+      gpr_log(GPR_ERROR,
+              "Invalid entry in accept encoding metadata: '%s'. Ignoring.",
+              accept_encoding_entry_str);
+      gpr_free(accept_encoding_entry_str);
+    }
+  }
+}
+
+gpr_uint32 grpc_call_get_encodings_accepted_by_peer(grpc_call *call) {
+  return call->encodings_accepted_by_peer;
+}
+
+gpr_uint32 grpc_call_get_message_flags(const grpc_call *call) {
+  return call->incoming_message_flags;
+}
+
 static void set_status_details(grpc_call *call, status_source source,
                                grpc_mdstr *status) {
   if (call->status[source].details != NULL) {
@@ -1001,10 +1046,11 @@ static int prepare_application_metadata(grpc_call *call, size_t count,
                                                (const gpr_uint8 *)md->value,
                                                md->value_length, 1);
     if (!grpc_mdstr_is_legal_header(l->md->key)) {
-      gpr_log(GPR_ERROR, "attempt to send invalid metadata key");
+      gpr_log(GPR_ERROR, "attempt to send invalid metadata key: %s",
+              grpc_mdstr_as_c_string(l->md->key));
       return 0;
     } else if (!grpc_mdstr_is_bin_suffixed(l->md->key) &&
-               !grpc_mdstr_is_legal_header(l->md->value)) {
+               !grpc_mdstr_is_legal_nonbin_header(l->md->value)) {
       gpr_log(GPR_ERROR, "attempt to send invalid metadata value");
       return 0;
     }
@@ -1280,7 +1326,7 @@ grpc_call_error grpc_call_cancel_with_status(grpc_call *c,
                                              const char *description,
                                              void *reserved) {
   grpc_call_error r;
-  (void) reserved;
+  (void)reserved;
   lock(c);
   r = cancel_with_status(c, status, description);
   unlock(c);
@@ -1408,10 +1454,11 @@ static gpr_uint32 decode_compression(grpc_mdelem *md) {
   void *user_data = grpc_mdelem_get_user_data(md, destroy_compression);
   if (user_data) {
     algorithm =
-        ((grpc_compression_level)(gpr_intptr)user_data) - COMPRESS_OFFSET;
+        ((grpc_compression_algorithm)(gpr_intptr)user_data) - COMPRESS_OFFSET;
   } else {
     const char *md_c_str = grpc_mdstr_as_c_string(md->value);
-    if (!grpc_compression_algorithm_parse(md_c_str, &algorithm)) {
+    if (!grpc_compression_algorithm_parse(md_c_str, strlen(md_c_str),
+                                          &algorithm)) {
       gpr_log(GPR_ERROR, "Invalid compression algorithm: '%s'", md_c_str);
       assert(0);
     }
@@ -1440,6 +1487,9 @@ static void recv_metadata(grpc_call *call, grpc_metadata_batch *md) {
     } else if (key ==
                grpc_channel_get_compression_algorithm_string(call->channel)) {
       set_compression_algorithm(call, decode_compression(md));
+    } else if (key == grpc_channel_get_encodings_accepted_by_peer_string(
+                          call->channel)) {
+      set_encodings_accepted_by_peer(call, md->value->slice);
     } else {
       dest = &call->buffered_metadata[is_trailing];
       if (dest->count == dest->capacity) {
@@ -1524,7 +1574,8 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
   const grpc_op *op;
   grpc_ioreq *req;
   void (*finish_func)(grpc_call *, int, void *) = finish_batch;
-  GPR_ASSERT(!reserved);
+
+  if (reserved != NULL) return GRPC_CALL_ERROR;
 
   GRPC_CALL_LOG_BATCH(GPR_INFO, call, ops, nops, tag);
 
@@ -1539,12 +1590,13 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
   /* rewrite batch ops into ioreq ops */
   for (in = 0, out = 0; in < nops; in++) {
     op = &ops[in];
+    if (op->reserved != NULL) return GRPC_CALL_ERROR;
     switch (op->op) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         /* Flag validation: currently allow no flags */
         if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_SEND_INITIAL_METADATA;
         req->data.send_metadata.count = op->data.send_initial_metadata.count;
         req->data.send_metadata.metadata =
@@ -1559,7 +1611,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
           return GRPC_CALL_ERROR_INVALID_MESSAGE;
         }
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_SEND_MESSAGE;
         req->data.send_message = op->data.send_message;
         req->flags = op->flags;
@@ -1571,7 +1623,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_SEND_CLOSE;
         req->flags = op->flags;
         break;
@@ -1582,7 +1634,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
           return GRPC_CALL_ERROR_NOT_ON_CLIENT;
         }
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_SEND_TRAILING_METADATA;
         req->flags = op->flags;
         req->data.send_metadata.count =
@@ -1590,7 +1642,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         req->data.send_metadata.metadata =
             op->data.send_status_from_server.trailing_metadata;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_SEND_STATUS;
         req->data.send_status.code = op->data.send_status_from_server.status;
         req->data.send_status.details =
@@ -1600,7 +1652,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
                       op->data.send_status_from_server.status_details, 0)
                 : NULL;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_SEND_CLOSE;
         break;
       case GRPC_OP_RECV_INITIAL_METADATA:
@@ -1610,7 +1662,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_INITIAL_METADATA;
         req->data.recv_metadata = op->data.recv_initial_metadata;
         req->data.recv_metadata->count = 0;
@@ -1620,7 +1672,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         /* Flag validation: currently allow no flags */
         if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_MESSAGE;
         req->data.recv_message = op->data.recv_message;
         req->flags = op->flags;
@@ -1632,26 +1684,26 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_STATUS;
         req->flags = op->flags;
         req->data.recv_status.set_value = set_status_value_directly;
         req->data.recv_status.user_data = op->data.recv_status_on_client.status;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_STATUS_DETAILS;
         req->data.recv_status_details.details =
             op->data.recv_status_on_client.status_details;
         req->data.recv_status_details.details_capacity =
             op->data.recv_status_on_client.status_details_capacity;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_TRAILING_METADATA;
         req->data.recv_metadata =
             op->data.recv_status_on_client.trailing_metadata;
         req->data.recv_metadata->count = 0;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_CLOSE;
         finish_func = finish_batch_with_close;
         break;
@@ -1659,14 +1711,14 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         /* Flag validation: currently allow no flags */
         if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_STATUS;
         req->flags = op->flags;
         req->data.recv_status.set_value = set_cancelled_value;
         req->data.recv_status.user_data =
             op->data.recv_close_on_server.cancelled;
         req = &reqs[out++];
-	if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
+        if (out > GRPC_IOREQ_OP_COUNT) return GRPC_CALL_ERROR_BATCH_TOO_BIG;
         req->op = GRPC_IOREQ_RECV_CLOSE;
         finish_func = finish_batch_with_close;
         break;
diff --git a/src/core/surface/call.h b/src/core/surface/call.h
index 75bdbce980..00638e43b5 100644
--- a/src/core/surface/call.h
+++ b/src/core/surface/call.h
@@ -38,6 +38,10 @@
 #include "src/core/channel/context.h"
 #include <grpc/grpc.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Primitive operation types - grpc_op's get rewritten into these */
 typedef enum {
   GRPC_IOREQ_RECV_INITIAL_METADATA,
@@ -162,4 +166,19 @@ void *grpc_call_context_get(grpc_call *call, grpc_context_index elem);
 
 gpr_uint8 grpc_call_is_client(grpc_call *call);
 
+grpc_compression_algorithm grpc_call_get_compression_algorithm(
+    const grpc_call *call);
+
+gpr_uint32 grpc_call_get_message_flags(const grpc_call *call);
+
+/** Returns a bitset for the encodings (compression algorithms) supported by \a
+ * call's peer.
+ *
+ * To be indexed by grpc_compression_algorithm enum values. */
+gpr_uint32 grpc_call_get_encodings_accepted_by_peer(grpc_call *call);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_INTERNAL_CORE_SURFACE_CALL_H */
diff --git a/src/core/surface/call_log_batch.c b/src/core/surface/call_log_batch.c
index 7bf8cafc24..5a3ef1e5f4 100644
--- a/src/core/surface/call_log_batch.c
+++ b/src/core/surface/call_log_batch.c
@@ -41,7 +41,7 @@ int grpc_trace_batch = 0;
 
 static void add_metadata(gpr_strvec *b, const grpc_metadata *md, size_t count) {
   size_t i;
-  for(i = 0; i < count; i++) {
+  for (i = 0; i < count; i++) {
     gpr_strvec_add(b, gpr_strdup("\nkey="));
     gpr_strvec_add(b, gpr_strdup(md[i].key));
 
@@ -113,8 +113,9 @@ void grpc_call_log_batch(char *file, int line, gpr_log_severity severity,
   char *tmp;
   size_t i;
   gpr_log(file, line, severity,
-          "grpc_call_start_batch(call=%p, ops=%p, nops=%d, tag=%p)", call, ops, nops, tag);
-  for(i = 0; i < nops; i++) {
+          "grpc_call_start_batch(call=%p, ops=%p, nops=%d, tag=%p)", call, ops,
+          nops, tag);
+  for (i = 0; i < nops; i++) {
     tmp = grpc_op_string(&ops[i]);
     gpr_log(file, line, severity, "ops[%d]: %s", i, tmp);
     gpr_free(tmp);
@@ -123,8 +124,7 @@ void grpc_call_log_batch(char *file, int line, gpr_log_severity severity,
 
 void grpc_server_log_request_call(char *file, int line,
                                   gpr_log_severity severity,
-                                  grpc_server *server,
-                                  grpc_call **call,
+                                  grpc_server *server, grpc_call **call,
                                   grpc_call_details *details,
                                   grpc_metadata_array *initial_metadata,
                                   grpc_completion_queue *cq_bound_to_call,
@@ -133,8 +133,9 @@ void grpc_server_log_request_call(char *file, int line,
   gpr_log(file, line, severity,
           "grpc_server_request_call(server=%p, call=%p, details=%p, "
           "initial_metadata=%p, cq_bound_to_call=%p, cq_for_notification=%p, "
-          "tag=%p)", server, call, details, initial_metadata,
-          cq_bound_to_call, cq_for_notification, tag);
+          "tag=%p)",
+          server, call, details, initial_metadata, cq_bound_to_call,
+          cq_for_notification, tag);
 }
 
 void grpc_server_log_shutdown(char *file, int line, gpr_log_severity severity,
diff --git a/src/core/surface/channel.c b/src/core/surface/channel.c
index 308572c634..586402e21c 100644
--- a/src/core/surface/channel.c
+++ b/src/core/surface/channel.c
@@ -40,6 +40,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/client_config/resolver_registry.h"
 #include "src/core/iomgr/iomgr.h"
 #include "src/core/support/string.h"
 #include "src/core/surface/call.h"
@@ -66,9 +67,11 @@ struct grpc_channel {
   /** mdstr for the grpc-status key */
   grpc_mdstr *grpc_status_string;
   grpc_mdstr *grpc_compression_algorithm_string;
+  grpc_mdstr *grpc_encodings_accepted_by_peer_string;
   grpc_mdstr *grpc_message_string;
   grpc_mdstr *path_string;
   grpc_mdstr *authority_string;
+  grpc_mdelem *default_authority;
   /** mdelem for grpc-status: 0 thru grpc-status: 2 */
   grpc_mdelem *grpc_status_elem[NUM_CACHED_STATUS_ELEMS];
 
@@ -104,7 +107,10 @@ grpc_channel *grpc_channel_create_from_filters(
   channel->grpc_status_string = grpc_mdstr_from_string(mdctx, "grpc-status", 0);
   channel->grpc_compression_algorithm_string =
       grpc_mdstr_from_string(mdctx, "grpc-encoding", 0);
-  channel->grpc_message_string = grpc_mdstr_from_string(mdctx, "grpc-message", 0);
+  channel->grpc_encodings_accepted_by_peer_string =
+      grpc_mdstr_from_string(mdctx, "grpc-accept-encoding", 0);
+  channel->grpc_message_string =
+      grpc_mdstr_from_string(mdctx, "grpc-message", 0);
   for (i = 0; i < NUM_CACHED_STATUS_ELEMS; i++) {
     char buf[GPR_LTOA_MIN_BUFSIZE];
     gpr_ltoa(i, buf);
@@ -130,10 +136,47 @@ grpc_channel *grpc_channel_create_from_filters(
         } else {
           channel->max_message_length = args->args[i].value.integer;
         }
+      } else if (0 == strcmp(args->args[i].key, GRPC_ARG_DEFAULT_AUTHORITY)) {
+        if (args->args[i].type != GRPC_ARG_STRING) {
+          gpr_log(GPR_ERROR, "%s: must be an string",
+                  GRPC_ARG_DEFAULT_AUTHORITY);
+        } else {
+          if (channel->default_authority) {
+            /* setting this takes precedence over anything else */
+            GRPC_MDELEM_UNREF(channel->default_authority);
+          }
+          channel->default_authority = grpc_mdelem_from_strings(
+              mdctx, ":authority", args->args[i].value.string);
+        }
+      } else if (0 ==
+                 strcmp(args->args[i].key, GRPC_SSL_TARGET_NAME_OVERRIDE_ARG)) {
+        if (args->args[i].type != GRPC_ARG_STRING) {
+          gpr_log(GPR_ERROR, "%s: must be an string",
+                  GRPC_SSL_TARGET_NAME_OVERRIDE_ARG);
+        } else {
+          if (channel->default_authority) {
+            /* other ways of setting this (notably ssl) take precedence */
+            gpr_log(GPR_ERROR, "%s: default host already set some other way",
+                    GRPC_ARG_DEFAULT_AUTHORITY);
+          } else {
+            channel->default_authority = grpc_mdelem_from_strings(
+                mdctx, ":authority", args->args[i].value.string);
+          }
+        }
       }
     }
   }
 
+  if (channel->is_client && channel->default_authority == NULL &&
+      target != NULL) {
+    char *default_authority = grpc_get_default_authority(target);
+    if (default_authority) {
+      channel->default_authority = grpc_mdelem_from_strings(
+          channel->metadata_context, ":authority", default_authority);
+    }
+    gpr_free(default_authority);
+  }
+
   grpc_channel_stack_init(filters, num_filters, channel, args,
                           channel->metadata_context,
                           CHANNEL_STACK_FROM_CHANNEL(channel));
@@ -157,9 +200,11 @@ static grpc_call *grpc_channel_create_call_internal(
   send_metadata[num_metadata++] = path_mdelem;
   if (authority_mdelem != NULL) {
     send_metadata[num_metadata++] = authority_mdelem;
+  } else if (channel->default_authority != NULL) {
+    send_metadata[num_metadata++] = GRPC_MDELEM_REF(channel->default_authority);
   }
 
-  return grpc_call_create(channel, parent_call, propagation_mask, cq, NULL, 
+  return grpc_call_create(channel, parent_call, propagation_mask, cq, NULL,
                           send_metadata, num_metadata, deadline);
 }
 
@@ -175,10 +220,11 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
       grpc_mdelem_from_metadata_strings(
           channel->metadata_context, GRPC_MDSTR_REF(channel->path_string),
           grpc_mdstr_from_string(channel->metadata_context, method, 0)),
-      host ?
-      grpc_mdelem_from_metadata_strings(
-          channel->metadata_context, GRPC_MDSTR_REF(channel->authority_string),
-          grpc_mdstr_from_string(channel->metadata_context, host, 0)) : NULL,
+      host ? grpc_mdelem_from_metadata_strings(
+                 channel->metadata_context,
+                 GRPC_MDSTR_REF(channel->authority_string),
+                 grpc_mdstr_from_string(channel->metadata_context, host, 0))
+           : NULL,
       deadline);
 }
 
@@ -189,9 +235,12 @@ void *grpc_channel_register_call(grpc_channel *channel, const char *method,
   rc->path = grpc_mdelem_from_metadata_strings(
       channel->metadata_context, GRPC_MDSTR_REF(channel->path_string),
       grpc_mdstr_from_string(channel->metadata_context, method, 0));
-  rc->authority = host ? grpc_mdelem_from_metadata_strings(
-      channel->metadata_context, GRPC_MDSTR_REF(channel->authority_string),
-      grpc_mdstr_from_string(channel->metadata_context, host, 0)) : NULL;
+  rc->authority =
+      host ? grpc_mdelem_from_metadata_strings(
+                 channel->metadata_context,
+                 GRPC_MDSTR_REF(channel->authority_string),
+                 grpc_mdstr_from_string(channel->metadata_context, host, 0))
+           : NULL;
   gpr_mu_lock(&channel->registered_call_mu);
   rc->next = channel->registered_calls;
   channel->registered_calls = rc;
@@ -206,8 +255,8 @@ grpc_call *grpc_channel_create_registered_call(
   registered_call *rc = registered_call_handle;
   GPR_ASSERT(!reserved);
   return grpc_channel_create_call_internal(
-      channel, parent_call, propagation_mask, completion_queue, 
-      GRPC_MDELEM_REF(rc->path), 
+      channel, parent_call, propagation_mask, completion_queue,
+      GRPC_MDELEM_REF(rc->path),
       rc->authority ? GRPC_MDELEM_REF(rc->authority) : NULL, deadline);
 }
 
@@ -230,6 +279,7 @@ static void destroy_channel(void *p, int ok) {
   }
   GRPC_MDSTR_UNREF(channel->grpc_status_string);
   GRPC_MDSTR_UNREF(channel->grpc_compression_algorithm_string);
+  GRPC_MDSTR_UNREF(channel->grpc_encodings_accepted_by_peer_string);
   GRPC_MDSTR_UNREF(channel->grpc_message_string);
   GRPC_MDSTR_UNREF(channel->path_string);
   GRPC_MDSTR_UNREF(channel->authority_string);
@@ -242,6 +292,9 @@ static void destroy_channel(void *p, int ok) {
     }
     gpr_free(rc);
   }
+  if (channel->default_authority != NULL) {
+    GRPC_MDELEM_UNREF(channel->default_authority);
+  }
   grpc_mdctx_unref(channel->metadata_context);
   gpr_mu_destroy(&channel->registered_call_mu);
   gpr_free(channel->target);
@@ -290,6 +343,11 @@ grpc_mdstr *grpc_channel_get_compression_algorithm_string(
   return channel->grpc_compression_algorithm_string;
 }
 
+grpc_mdstr *grpc_channel_get_encodings_accepted_by_peer_string(
+    grpc_channel *channel) {
+  return channel->grpc_encodings_accepted_by_peer_string;
+}
+
 grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel, int i) {
   if (i >= 0 && i < NUM_CACHED_STATUS_ELEMS) {
     return GRPC_MDELEM_REF(channel->grpc_status_elem[i]);
diff --git a/src/core/surface/channel.h b/src/core/surface/channel.h
index 9e0646efaa..f271616f60 100644
--- a/src/core/surface/channel.h
+++ b/src/core/surface/channel.h
@@ -56,6 +56,8 @@ grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel,
 grpc_mdstr *grpc_channel_get_status_string(grpc_channel *channel);
 grpc_mdstr *grpc_channel_get_compression_algorithm_string(
     grpc_channel *channel);
+grpc_mdstr *grpc_channel_get_encodings_accepted_by_peer_string(
+    grpc_channel *channel);
 grpc_mdstr *grpc_channel_get_message_string(grpc_channel *channel);
 gpr_uint32 grpc_channel_get_max_message_length(grpc_channel *channel);
 
diff --git a/src/core/surface/channel_connectivity.c b/src/core/surface/channel_connectivity.c
index 1223706457..88a7c16598 100644
--- a/src/core/surface/channel_connectivity.c
+++ b/src/core/surface/channel_connectivity.c
@@ -77,9 +77,10 @@ typedef struct {
 } state_watcher;
 
 static void delete_state_watcher(state_watcher *w) {
-  grpc_channel_element *client_channel_elem =
-      grpc_channel_stack_last_element(grpc_channel_get_channel_stack(w->channel));
-  grpc_client_channel_del_interested_party(client_channel_elem, grpc_cq_pollset(w->cq));
+  grpc_channel_element *client_channel_elem = grpc_channel_stack_last_element(
+      grpc_channel_get_channel_stack(w->channel));
+  grpc_client_channel_del_interested_party(client_channel_elem,
+                                           grpc_cq_pollset(w->cq));
   GRPC_CHANNEL_INTERNAL_UNREF(w->channel, "watch_connectivity");
   gpr_mu_destroy(&w->mu);
   gpr_free(w);
@@ -166,9 +167,9 @@ void grpc_channel_watch_connectivity_state(
   w->tag = tag;
   w->channel = channel;
 
-  grpc_alarm_init(
-      &w->alarm, gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC), 
-      timeout_complete, w, gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_alarm_init(&w->alarm,
+                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
+                  timeout_complete, w, gpr_now(GPR_CLOCK_MONOTONIC));
 
   if (client_channel_elem->filter != &grpc_client_channel_filter) {
     gpr_log(GPR_ERROR,
@@ -178,7 +179,8 @@ void grpc_channel_watch_connectivity_state(
     grpc_iomgr_add_delayed_callback(&w->on_complete, 1);
   } else {
     GRPC_CHANNEL_INTERNAL_REF(channel, "watch_connectivity");
-    grpc_client_channel_add_interested_party(client_channel_elem, grpc_cq_pollset(cq));
+    grpc_client_channel_add_interested_party(client_channel_elem,
+                                             grpc_cq_pollset(cq));
     grpc_client_channel_watch_connectivity_state(client_channel_elem, &w->state,
                                                  &w->on_complete);
   }
diff --git a/src/core/surface/channel_create.c b/src/core/surface/channel_create.c
index 82ddfac757..707251da89 100644
--- a/src/core/surface/channel_create.c
+++ b/src/core/surface/channel_create.c
@@ -38,6 +38,7 @@
 
 #include <grpc/support/alloc.h>
 
+#include "src/core/census/grpc_filter.h"
 #include "src/core/channel/channel_args.h"
 #include "src/core/channel/client_channel.h"
 #include "src/core/channel/compress_filter.h"
@@ -165,10 +166,9 @@ grpc_channel *grpc_insecure_channel_create(const char *target,
   grpc_mdctx *mdctx = grpc_mdctx_create();
   int n = 0;
   GPR_ASSERT(!reserved);
-  /* TODO(census)
   if (grpc_channel_args_is_census_enabled(args)) {
     filters[n++] = &grpc_client_census_filter;
-    } */
+  }
   filters[n++] = &grpc_compress_filter;
   filters[n++] = &grpc_client_channel_filter;
   GPR_ASSERT(n <= MAX_FILTERS);
diff --git a/src/core/surface/completion_queue.c b/src/core/surface/completion_queue.c
index 378b3f71a1..b58115a93f 100644
--- a/src/core/surface/completion_queue.c
+++ b/src/core/surface/completion_queue.c
@@ -167,10 +167,12 @@ void grpc_cq_end_op(grpc_completion_queue *cc, void *tag, int success,
 }
 
 grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
-                                      gpr_timespec deadline,
-                                      void *reserved) {
+                                      gpr_timespec deadline, void *reserved) {
   grpc_event ret;
   grpc_pollset_worker worker;
+  int first_loop = 1;
+  gpr_timespec now;
+
   GPR_ASSERT(!reserved);
 
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
@@ -197,12 +199,15 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
       ret.type = GRPC_QUEUE_SHUTDOWN;
       break;
     }
-    if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
+    now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (!first_loop && gpr_time_cmp(now, deadline) >= 0) {
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
+    first_loop = 0;
+    grpc_pollset_work(&cc->pollset, &worker, now, deadline);
   }
   GRPC_SURFACE_TRACE_RETURNED_EVENT(cc, &ret);
   GRPC_CQ_INTERNAL_UNREF(cc, "next");
@@ -240,6 +245,9 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
   grpc_cq_completion *c;
   grpc_cq_completion *prev;
   grpc_pollset_worker worker;
+  gpr_timespec now;
+  int first_loop = 1;
+
   GPR_ASSERT(!reserved);
 
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
@@ -272,8 +280,9 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
       break;
     }
     if (!add_plucker(cc, tag, &worker)) {
-      gpr_log(GPR_DEBUG, 
-              "Too many outstanding grpc_completion_queue_pluck calls: maximum is %d",
+      gpr_log(GPR_DEBUG,
+              "Too many outstanding grpc_completion_queue_pluck calls: maximum "
+              "is %d",
               GRPC_MAX_COMPLETION_QUEUE_PLUCKERS);
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
@@ -281,13 +290,16 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
-    if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
+    now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (!first_loop && gpr_time_cmp(now, deadline) >= 0) {
       del_plucker(cc, tag, &worker);
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
+    first_loop = 0;
+    grpc_pollset_work(&cc->pollset, &worker, now, deadline);
     del_plucker(cc, tag, &worker);
   }
 done:
diff --git a/src/core/surface/event_string.h b/src/core/surface/event_string.h
index e8a8f93518..07c474e3a0 100644
--- a/src/core/surface/event_string.h
+++ b/src/core/surface/event_string.h
@@ -39,4 +39,4 @@
 /* Returns a string describing an event. Must be later freed with gpr_free() */
 char *grpc_event_string(grpc_event *ev);
 
-#endif  /* GRPC_INTERNAL_CORE_SURFACE_EVENT_STRING_H */
+#endif /* GRPC_INTERNAL_CORE_SURFACE_EVENT_STRING_H */
diff --git a/src/core/surface/init.c b/src/core/surface/init.c
index 442bc72f21..0d48cd42d7 100644
--- a/src/core/surface/init.c
+++ b/src/core/surface/init.c
@@ -33,8 +33,11 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <memory.h>
+
 #include <grpc/census.h>
 #include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
 #include <grpc/support/time.h>
 #include "src/core/channel/channel_stack.h"
 #include "src/core/client_config/resolver_registry.h"
@@ -49,6 +52,8 @@
 #include "src/core/transport/chttp2_transport.h"
 #include "src/core/transport/connectivity_state.h"
 
+#define MAX_PLUGINS 128
+
 static gpr_once g_basic_init = GPR_ONCE_INIT;
 static gpr_mu g_init_mu;
 static int g_initializations;
@@ -58,18 +63,34 @@ static void do_basic_init(void) {
   g_initializations = 0;
 }
 
+typedef struct grpc_plugin {
+  void (*init)();
+  void (*destroy)();
+} grpc_plugin;
+
+static grpc_plugin g_all_of_the_plugins[MAX_PLUGINS];
+static int g_number_of_plugins = 0;
+
+void grpc_register_plugin(void (*init)(void), void (*destroy)(void)) {
+  GPR_ASSERT(g_number_of_plugins != MAX_PLUGINS);
+  g_all_of_the_plugins[g_number_of_plugins].init = init;
+  g_all_of_the_plugins[g_number_of_plugins].destroy = destroy;
+  g_number_of_plugins++;
+}
+
 void grpc_init(void) {
+  int i;
   gpr_once_init(&g_basic_init, do_basic_init);
 
   gpr_mu_lock(&g_init_mu);
   if (++g_initializations == 1) {
     gpr_time_init();
     grpc_resolver_registry_init("dns:///");
-    grpc_register_resolver_type("dns", grpc_dns_resolver_factory_create());
-    grpc_register_resolver_type("ipv4", grpc_ipv4_resolver_factory_create());
-    grpc_register_resolver_type("ipv6", grpc_ipv6_resolver_factory_create());
+    grpc_register_resolver_type(grpc_dns_resolver_factory_create());
+    grpc_register_resolver_type(grpc_ipv4_resolver_factory_create());
+    grpc_register_resolver_type(grpc_ipv6_resolver_factory_create());
 #ifdef GPR_POSIX_SOCKET
-    grpc_register_resolver_type("unix", grpc_unix_resolver_factory_create());
+    grpc_register_resolver_type(grpc_unix_resolver_factory_create());
 #endif
     grpc_register_tracer("channel", &grpc_trace_channel);
     grpc_register_tracer("surface", &grpc_surface_trace);
@@ -87,11 +108,17 @@ void grpc_init(void) {
       }
     }
     grpc_timers_global_init();
+    for (i = 0; i < g_number_of_plugins; i++) {
+      if (g_all_of_the_plugins[i].init != NULL) {
+        g_all_of_the_plugins[i].init();
+      }
+    }
   }
   gpr_mu_unlock(&g_init_mu);
 }
 
 void grpc_shutdown(void) {
+  int i;
   gpr_mu_lock(&g_init_mu);
   if (--g_initializations == 0) {
     grpc_iomgr_shutdown();
@@ -99,6 +126,11 @@ void grpc_shutdown(void) {
     grpc_timers_global_destroy();
     grpc_tracer_shutdown();
     grpc_resolver_registry_shutdown();
+    for (i = 0; i < g_number_of_plugins; i++) {
+      if (g_all_of_the_plugins[i].destroy != NULL) {
+        g_all_of_the_plugins[i].destroy();
+      }
+    }
   }
   gpr_mu_unlock(&g_init_mu);
 }
diff --git a/src/core/surface/init.h b/src/core/surface/init.h
index 416874020d..771c30f412 100644
--- a/src/core/surface/init.h
+++ b/src/core/surface/init.h
@@ -37,4 +37,4 @@
 void grpc_security_pre_init(void);
 int grpc_is_initialized(void);
 
-#endif  /* GRPC_INTERNAL_CORE_SURFACE_INIT_H */
+#endif /* GRPC_INTERNAL_CORE_SURFACE_INIT_H */
diff --git a/src/core/surface/init_unsecure.c b/src/core/surface/init_unsecure.c
index ddb70cef8e..630d564a7d 100644
--- a/src/core/surface/init_unsecure.c
+++ b/src/core/surface/init_unsecure.c
@@ -33,5 +33,4 @@
 
 #include "src/core/surface/init.h"
 
-void grpc_security_pre_init(void) {
-}
+void grpc_security_pre_init(void) {}
diff --git a/src/core/surface/lame_client.c b/src/core/surface/lame_client.c
index c4215a2cfb..80704cbf67 100644
--- a/src/core/surface/lame_client.c
+++ b/src/core/surface/lame_client.c
@@ -50,6 +50,8 @@ typedef struct {
 typedef struct {
   grpc_mdctx *mdctx;
   grpc_channel *master;
+  grpc_status_code error_code;
+  const char *error_message;
 } channel_data;
 
 static void lame_start_transport_stream_op(grpc_call_element *elem,
@@ -64,11 +66,11 @@ static void lame_start_transport_stream_op(grpc_call_element *elem,
   if (op->recv_ops != NULL) {
     char tmp[GPR_LTOA_MIN_BUFSIZE];
     grpc_metadata_batch mdb;
-    gpr_ltoa(GRPC_STATUS_UNKNOWN, tmp);
+    gpr_ltoa(chand->error_code, tmp);
     calld->status.md =
         grpc_mdelem_from_strings(chand->mdctx, "grpc-status", tmp);
     calld->details.md = grpc_mdelem_from_strings(chand->mdctx, "grpc-message",
-                                                 "Rpc sent on a lame channel.");
+                                                 chand->error_message);
     calld->status.prev = calld->details.next = NULL;
     calld->status.next = &calld->details;
     calld->details.prev = &calld->status;
@@ -138,8 +140,21 @@ static const grpc_channel_filter lame_filter = {
     "lame-client",
 };
 
-grpc_channel *grpc_lame_client_channel_create(const char *target) {
+#define CHANNEL_STACK_FROM_CHANNEL(c) ((grpc_channel_stack *)((c) + 1))
+
+grpc_channel *grpc_lame_client_channel_create(const char *target,
+                                              grpc_status_code error_code,
+                                              const char *error_message) {
+  grpc_channel *channel;
+  grpc_channel_element *elem;
+  channel_data *chand;
   static const grpc_channel_filter *filters[] = {&lame_filter};
-  return grpc_channel_create_from_filters(target, filters, 1, NULL,
-                                          grpc_mdctx_create(), 1);
+  channel = grpc_channel_create_from_filters(target, filters, 1, NULL,
+                                             grpc_mdctx_create(), 1);
+  elem = grpc_channel_stack_element(grpc_channel_get_channel_stack(channel), 0);
+  GPR_ASSERT(elem->filter == &lame_filter);
+  chand = (channel_data *)elem->channel_data;
+  chand->error_code = error_code;
+  chand->error_message = error_message;
+  return channel;
 }
diff --git a/src/core/surface/secure_channel_create.c b/src/core/surface/secure_channel_create.c
index c3150250b8..eccee24698 100644
--- a/src/core/surface/secure_channel_create.c
+++ b/src/core/surface/secure_channel_create.c
@@ -38,6 +38,7 @@
 
 #include <grpc/support/alloc.h>
 
+#include "src/core/census/grpc_filter.h"
 #include "src/core/channel/channel_args.h"
 #include "src/core/channel/client_channel.h"
 #include "src/core/channel/compress_filter.h"
@@ -199,13 +200,17 @@ grpc_channel *grpc_secure_channel_create(grpc_credentials *creds,
 
   if (grpc_find_security_connector_in_args(args) != NULL) {
     gpr_log(GPR_ERROR, "Cannot set security context in channel args.");
-    return grpc_lame_client_channel_create(target);
+    return grpc_lame_client_channel_create(
+        target, GRPC_STATUS_INVALID_ARGUMENT,
+        "Security connector exists in channel args.");
   }
 
   if (grpc_credentials_create_security_connector(
           creds, target, args, NULL, &connector, &new_args_from_connector) !=
       GRPC_SECURITY_OK) {
-    return grpc_lame_client_channel_create(target);
+    return grpc_lame_client_channel_create(
+        target, GRPC_STATUS_INVALID_ARGUMENT,
+        "Failed to create security connector.");
   }
   mdctx = grpc_mdctx_create();
 
@@ -213,10 +218,9 @@ grpc_channel *grpc_secure_channel_create(grpc_credentials *creds,
   args_copy = grpc_channel_args_copy_and_add(
       new_args_from_connector != NULL ? new_args_from_connector : args,
       &connector_arg, 1);
-  /* TODO(census)
   if (grpc_channel_args_is_census_enabled(args)) {
     filters[n++] = &grpc_client_census_filter;
-    } */
+  }
   filters[n++] = &grpc_compress_filter;
   filters[n++] = &grpc_client_channel_filter;
   GPR_ASSERT(n <= MAX_FILTERS);
diff --git a/src/core/surface/server.c b/src/core/surface/server.c
index f883275951..292bf6fab8 100644
--- a/src/core/surface/server.c
+++ b/src/core/surface/server.c
@@ -41,7 +41,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
-#include "src/core/channel/census_filter.h"
+#include "src/core/census/grpc_filter.h"
 #include "src/core/channel/channel_args.h"
 #include "src/core/channel/connected_channel.h"
 #include "src/core/iomgr/iomgr.h"
@@ -712,7 +712,8 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
   chand->server = NULL;
   chand->channel = NULL;
   chand->path_key = grpc_mdstr_from_string(metadata_context, ":path", 0);
-  chand->authority_key = grpc_mdstr_from_string(metadata_context, ":authority", 0);
+  chand->authority_key =
+      grpc_mdstr_from_string(metadata_context, ":authority", 0);
   chand->next = chand->prev = chand;
   chand->registered_methods = NULL;
   chand->connectivity_state = GRPC_CHANNEL_IDLE;
@@ -820,10 +821,9 @@ grpc_server *grpc_server_create_from_filters(
   server->channel_filters =
       gpr_malloc(server->channel_filter_count * sizeof(grpc_channel_filter *));
   server->channel_filters[0] = &server_surface_filter;
-  /* TODO(census): restore this once we rework census filter
   if (census_enabled) {
     server->channel_filters[1] = &grpc_server_census_filter;
-    } */
+  }
   for (i = 0; i < filter_count; i++) {
     server->channel_filters[i + 1 + census_enabled] = filters[i];
   }
@@ -974,6 +974,11 @@ void grpc_server_setup_transport(grpc_server *s, grpc_transport *transport,
   grpc_transport_perform_op(transport, &op);
 }
 
+void done_published_shutdown(void *done_arg, grpc_cq_completion *storage) {
+  (void) done_arg;
+  gpr_free(storage);
+}
+
 void grpc_server_shutdown_and_notify(grpc_server *server,
                                      grpc_completion_queue *cq, void *tag) {
   listener *l;
@@ -985,6 +990,12 @@ void grpc_server_shutdown_and_notify(grpc_server *server,
   /* lock, and gather up some stuff to do */
   gpr_mu_lock(&server->mu_global);
   grpc_cq_begin_op(cq);
+  if (server->shutdown_published) {
+    grpc_cq_end_op(cq, tag, 1, done_published_shutdown, NULL,
+                   gpr_malloc(sizeof(grpc_cq_completion)));
+    gpr_mu_unlock(&server->mu_global);
+    return;
+  }
   server->shutdown_tags =
       gpr_realloc(server->shutdown_tags,
                   sizeof(shutdown_tag) * (server->num_shutdown_tags + 1));
@@ -1134,6 +1145,7 @@ grpc_call_error grpc_server_request_call(
     return GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE;
   }
   grpc_cq_begin_op(cq_for_notification);
+  details->reserved = NULL;
   rc->type = BATCH_CALL;
   rc->server = server;
   rc->tag = tag;
diff --git a/src/core/surface/server_create.c b/src/core/surface/server_create.c
index 9237eb5a90..fc7ae820f5 100644
--- a/src/core/surface/server_create.c
+++ b/src/core/surface/server_create.c
@@ -38,7 +38,7 @@
 
 grpc_server *grpc_server_create(const grpc_channel_args *args, void *reserved) {
   const grpc_channel_filter *filters[] = {&grpc_compress_filter};
-  (void) reserved;
+  (void)reserved;
   return grpc_server_create_from_filters(filters, GPR_ARRAY_SIZE(filters),
                                          args);
 }
diff --git a/src/core/surface/surface_trace.h b/src/core/surface/surface_trace.h
index 01302bb5d4..2b4728e2b4 100644
--- a/src/core/surface/surface_trace.h
+++ b/src/core/surface/surface_trace.h
@@ -40,10 +40,10 @@
 extern int grpc_surface_trace;
 
 #define GRPC_SURFACE_TRACE_RETURNED_EVENT(cq, event)    \
-  if (grpc_surface_trace) {           \
+  if (grpc_surface_trace) {                             \
     char *_ev = grpc_event_string(event);               \
     gpr_log(GPR_INFO, "RETURN_EVENT[%p]: %s", cq, _ev); \
     gpr_free(_ev);                                      \
   }
 
-#endif  /* GRPC_INTERNAL_CORE_SURFACE_SURFACE_TRACE_H */
+#endif /* GRPC_INTERNAL_CORE_SURFACE_SURFACE_TRACE_H */
diff --git a/src/core/transport/chttp2/frame_data.c b/src/core/transport/chttp2/frame_data.c
index 40bf2ebd79..474c3d5ee6 100644
--- a/src/core/transport/chttp2/frame_data.c
+++ b/src/core/transport/chttp2/frame_data.c
@@ -92,10 +92,10 @@ grpc_chttp2_parse_error grpc_chttp2_data_parser_parse(
       p->frame_type = *cur;
       switch (p->frame_type) {
         case 0:
-          p->is_frame_compressed = 0;  /* GPR_FALSE */
+          p->is_frame_compressed = 0; /* GPR_FALSE */
           break;
         case 1:
-          p->is_frame_compressed = 1;  /* GPR_TRUE */
+          p->is_frame_compressed = 1; /* GPR_TRUE */
           break;
         default:
           gpr_log(GPR_ERROR, "Bad GRPC frame type 0x%02x", p->frame_type);
diff --git a/src/core/transport/chttp2/parsing.c b/src/core/transport/chttp2/parsing.c
index d84960009b..dc5eb18e42 100644
--- a/src/core/transport/chttp2/parsing.c
+++ b/src/core/transport/chttp2/parsing.c
@@ -177,10 +177,9 @@ void grpc_chttp2_publish_reads(
           "parsed", transport_parsing, stream_global, max_recv_bytes,
           -(gpr_int64)stream_parsing->incoming_window_delta);
       stream_global->incoming_window -= stream_parsing->incoming_window_delta;
-      GPR_ASSERT(stream_global->max_recv_bytes >= 
-          stream_parsing->incoming_window_delta);
-      stream_global->max_recv_bytes -= 
-          stream_parsing->incoming_window_delta;
+      GPR_ASSERT(stream_global->max_recv_bytes >=
+                 stream_parsing->incoming_window_delta);
+      stream_global->max_recv_bytes -= stream_parsing->incoming_window_delta;
       stream_parsing->incoming_window_delta = 0;
       grpc_chttp2_list_add_writable_stream(transport_global, stream_global);
     }
diff --git a/src/core/transport/chttp2/stream_encoder.c b/src/core/transport/chttp2/stream_encoder.c
index 0f04169741..1ea697f71e 100644
--- a/src/core/transport/chttp2/stream_encoder.c
+++ b/src/core/transport/chttp2/stream_encoder.c
@@ -66,6 +66,8 @@ typedef struct {
   size_t header_idx;
   /* was the last frame emitted a header? (if yes, we'll need a CONTINUATION */
   gpr_uint8 last_was_header;
+  /* have we seen a regular (non-colon-prefixed) header yet? */
+  gpr_uint8 seen_regular_header;
   /* output stream id */
   gpr_uint32 stream_id;
   gpr_slice_buffer *output;
@@ -361,6 +363,15 @@ static grpc_mdelem *hpack_enc(grpc_chttp2_hpack_compressor *c,
   gpr_uint32 indices_key;
   int should_add_elem;
 
+  GPR_ASSERT (GPR_SLICE_LENGTH(elem->key->slice) > 0);
+  if (GPR_SLICE_START_PTR(elem->key->slice)[0] != ':') { /* regular header */
+    st->seen_regular_header = 1;
+  } else if (st->seen_regular_header != 0) { /* reserved header */
+    gpr_log(GPR_ERROR,
+            "Reserved header (colon-prefixed) happening after regular ones.");
+    abort();
+  }
+
   inc_filter(HASH_FRAGMENT_1(elem_hash), &c->filter_elems_sum, c->filter_elems);
 
   /* is this elem currently in the decoders table? */
@@ -566,6 +577,7 @@ void grpc_chttp2_encode(grpc_stream_op *ops, size_t ops_count, int eof,
 
   st.cur_frame_type = NONE;
   st.last_was_header = 0;
+  st.seen_regular_header = 0;
   st.stream_id = stream_id;
   st.output = output;
 
diff --git a/src/core/transport/chttp2/stream_lists.c b/src/core/transport/chttp2/stream_lists.c
index 9c3ad7a777..38c6052f9c 100644
--- a/src/core/transport/chttp2/stream_lists.c
+++ b/src/core/transport/chttp2/stream_lists.c
@@ -363,7 +363,7 @@ void grpc_chttp2_register_stream(grpc_chttp2_transport *t,
 }
 
 int grpc_chttp2_unregister_stream(grpc_chttp2_transport *t,
-                                   grpc_chttp2_stream *s) {
+                                  grpc_chttp2_stream *s) {
   stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_ALL_STREAMS);
   return stream_list_empty(t, GRPC_CHTTP2_LIST_ALL_STREAMS);
 }
diff --git a/src/core/transport/chttp2/stream_map.c b/src/core/transport/chttp2/stream_map.c
index 0ec2f27291..bd16153ed1 100644
--- a/src/core/transport/chttp2/stream_map.c
+++ b/src/core/transport/chttp2/stream_map.c
@@ -123,8 +123,7 @@ void grpc_chttp2_stream_map_move_into(grpc_chttp2_stream_map *src,
     dst->values = gpr_realloc(dst->values, dst->capacity * sizeof(void *));
   }
   memcpy(dst->keys + dst->count, src->keys, src->count * sizeof(gpr_uint32));
-  memcpy(dst->values + dst->count, src->values,
-         src->count * sizeof(void*));
+  memcpy(dst->values + dst->count, src->values, src->count * sizeof(void *));
   dst->count += src->count;
   dst->free += src->free;
   src->count = 0;
diff --git a/src/core/transport/chttp2/writing.c b/src/core/transport/chttp2/writing.c
index b55e81fdca..123061b3fc 100644
--- a/src/core/transport/chttp2/writing.c
+++ b/src/core/transport/chttp2/writing.c
@@ -112,13 +112,18 @@ int grpc_chttp2_unlocking_check_writes(
       }
     }
 
-    if (!stream_global->read_closed && stream_global->unannounced_incoming_window > 0) {
-      stream_writing->announce_window = stream_global->unannounced_incoming_window;
-      GRPC_CHTTP2_FLOWCTL_TRACE_STREAM("write", transport_global, stream_global,
-                                       incoming_window, stream_global->unannounced_incoming_window);
-      GRPC_CHTTP2_FLOWCTL_TRACE_STREAM("write", transport_global, stream_global,
-                                       unannounced_incoming_window, -(gpr_int64)stream_global->unannounced_incoming_window);
-      stream_global->incoming_window += stream_global->unannounced_incoming_window;
+    if (!stream_global->read_closed &&
+        stream_global->unannounced_incoming_window > 0) {
+      stream_writing->announce_window =
+          stream_global->unannounced_incoming_window;
+      GRPC_CHTTP2_FLOWCTL_TRACE_STREAM(
+          "write", transport_global, stream_global, incoming_window,
+          stream_global->unannounced_incoming_window);
+      GRPC_CHTTP2_FLOWCTL_TRACE_STREAM(
+          "write", transport_global, stream_global, unannounced_incoming_window,
+          -(gpr_int64)stream_global->unannounced_incoming_window);
+      stream_global->incoming_window +=
+          stream_global->unannounced_incoming_window;
       stream_global->unannounced_incoming_window = 0;
       grpc_chttp2_list_add_incoming_window_updated(transport_global,
                                                    stream_global);
@@ -179,18 +184,20 @@ static void finalize_outbuf(grpc_chttp2_transport_writing *transport_writing) {
 
   while (
       grpc_chttp2_list_pop_writing_stream(transport_writing, &stream_writing)) {
-    if (stream_writing->sopb.nops > 0 || stream_writing->send_closed != GRPC_DONT_SEND_CLOSED) {
+    if (stream_writing->sopb.nops > 0 ||
+        stream_writing->send_closed != GRPC_DONT_SEND_CLOSED) {
       grpc_chttp2_encode(stream_writing->sopb.ops, stream_writing->sopb.nops,
                          stream_writing->send_closed != GRPC_DONT_SEND_CLOSED,
-                         stream_writing->id, &transport_writing->hpack_compressor,
+                         stream_writing->id,
+                         &transport_writing->hpack_compressor,
                          &transport_writing->outbuf);
       stream_writing->sopb.nops = 0;
     }
     if (stream_writing->announce_window > 0) {
       gpr_slice_buffer_add(
           &transport_writing->outbuf,
-          grpc_chttp2_window_update_create(
-              stream_writing->id, stream_writing->announce_window));
+          grpc_chttp2_window_update_create(stream_writing->id,
+                                           stream_writing->announce_window));
       stream_writing->announce_window = 0;
     }
     if (stream_writing->send_closed == GRPC_SEND_CLOSED_WITH_RST_STREAM) {
diff --git a/src/core/transport/chttp2_transport.c b/src/core/transport/chttp2_transport.c
index a9f91b64d5..1bbd210e46 100644
--- a/src/core/transport/chttp2_transport.c
+++ b/src/core/transport/chttp2_transport.c
@@ -116,7 +116,7 @@ static void close_from_api(grpc_chttp2_transport_global *transport_global,
 static void add_to_pollset_locked(grpc_chttp2_transport *t,
                                   grpc_pollset *pollset);
 static void add_to_pollset_set_locked(grpc_chttp2_transport *t,
-                                  grpc_pollset_set *pollset_set);
+                                      grpc_pollset_set *pollset_set);
 
 /** Start new streams that have been created if we can */
 static void maybe_start_some_streams(
@@ -368,11 +368,10 @@ static int init_stream(grpc_transport *gt, grpc_stream *gs,
     s->global.outgoing_window =
         t->global.settings[GRPC_PEER_SETTINGS]
                           [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->global.max_recv_bytes = 
-        s->parsing.incoming_window = 
+    s->global.max_recv_bytes = s->parsing.incoming_window =
         s->global.incoming_window =
-        t->global.settings[GRPC_SENT_SETTINGS]
-                          [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
+            t->global.settings[GRPC_SENT_SETTINGS]
+                              [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
     *t->accepting_stream = s;
     grpc_chttp2_stream_map_add(&t->parsing_stream_map, s->global.id, s);
     s->global.in_stream_map = 1;
@@ -580,7 +579,7 @@ static void maybe_start_some_streams(
     stream_global->incoming_window =
         transport_global->settings[GRPC_SENT_SETTINGS]
                                   [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    stream_global->max_recv_bytes = 
+    stream_global->max_recv_bytes =
         GPR_MAX(stream_global->incoming_window, stream_global->max_recv_bytes);
     grpc_chttp2_stream_map_add(
         &TRANSPORT_FROM_GLOBAL(transport_global)->new_stream_map,
@@ -590,7 +589,6 @@ static void maybe_start_some_streams(
     grpc_chttp2_list_add_incoming_window_updated(transport_global,
                                                  stream_global);
     grpc_chttp2_list_add_writable_stream(transport_global, stream_global);
-
   }
   /* cancel out streams that will never be started */
   while (transport_global->next_stream_id >= MAX_CLIENT_STREAM_ID &&
@@ -648,12 +646,14 @@ static void perform_stream_op_locked(
     stream_global->publish_sopb->nops = 0;
     stream_global->publish_state = op->recv_state;
     if (stream_global->max_recv_bytes < op->max_recv_bytes) {
-      GRPC_CHTTP2_FLOWCTL_TRACE_STREAM("op", transport_global, stream_global,
-          max_recv_bytes, op->max_recv_bytes - stream_global->max_recv_bytes);
+      GRPC_CHTTP2_FLOWCTL_TRACE_STREAM(
+          "op", transport_global, stream_global, max_recv_bytes,
+          op->max_recv_bytes - stream_global->max_recv_bytes);
       GRPC_CHTTP2_FLOWCTL_TRACE_STREAM(
           "op", transport_global, stream_global, unannounced_incoming_window,
           op->max_recv_bytes - stream_global->max_recv_bytes);
-      stream_global->unannounced_incoming_window += op->max_recv_bytes - stream_global->max_recv_bytes;
+      stream_global->unannounced_incoming_window +=
+          op->max_recv_bytes - stream_global->max_recv_bytes;
       stream_global->max_recv_bytes = op->max_recv_bytes;
     }
     grpc_chttp2_incoming_metadata_live_op_buffer_end(
@@ -1175,7 +1175,7 @@ static void add_to_pollset_locked(grpc_chttp2_transport *t,
 }
 
 static void add_to_pollset_set_locked(grpc_chttp2_transport *t,
-                                  grpc_pollset_set *pollset_set) {
+                                      grpc_pollset_set *pollset_set) {
   if (t->ep) {
     grpc_endpoint_add_to_pollset_set(t->ep, pollset_set);
   }
diff --git a/src/core/transport/metadata.c b/src/core/transport/metadata.c
index 44d32b6cb2..3fd21a2f5d 100644
--- a/src/core/transport/metadata.c
+++ b/src/core/transport/metadata.c
@@ -133,8 +133,8 @@ static void unlock(grpc_mdctx *ctx) {
      case), since otherwise we can be stuck waiting for a garbage collection
      that will never happen. */
   if (ctx->refs == 0) {
-    /* uncomment if you're having trouble diagnosing an mdelem leak to make
-       things clearer (slows down destruction a lot, however) */
+/* uncomment if you're having trouble diagnosing an mdelem leak to make
+   things clearer (slows down destruction a lot, however) */
 #ifdef GRPC_METADATA_REFCOUNT_DEBUG
     gc_mdtab(ctx);
 #endif
@@ -311,7 +311,8 @@ static void slice_unref(void *p) {
   unlock(ctx);
 }
 
-grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str, int canonicalize_key) {
+grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str,
+                                   int canonicalize_key) {
   if (canonicalize_key) {
     size_t len;
     size_t i;
@@ -522,9 +523,9 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdctx *ctx,
 
 grpc_mdelem *grpc_mdelem_from_strings(grpc_mdctx *ctx, const char *key,
                                       const char *value) {
-  return grpc_mdelem_from_metadata_strings(ctx,
-                                           grpc_mdstr_from_string(ctx, key, 0),
-                                           grpc_mdstr_from_string(ctx, value, 0));
+  return grpc_mdelem_from_metadata_strings(
+      ctx, grpc_mdstr_from_string(ctx, key, 0),
+      grpc_mdstr_from_string(ctx, value, 0));
 }
 
 grpc_mdelem *grpc_mdelem_from_slices(grpc_mdctx *ctx, gpr_slice key,
@@ -680,16 +681,34 @@ void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx,
 
 void grpc_mdctx_unlock(grpc_mdctx *ctx) { unlock(ctx); }
 
-int grpc_mdstr_is_legal_header(grpc_mdstr *s) {
-  /* TODO(ctiller): consider caching this, or computing it on construction */
+static int conforms_to(grpc_mdstr *s, const gpr_uint8 *legal_bits) {
   const gpr_uint8 *p = GPR_SLICE_START_PTR(s->slice);
   const gpr_uint8 *e = GPR_SLICE_END_PTR(s->slice);
   for (; p != e; p++) {
-    if (*p < 32 || *p > 126) return 0;
+    int idx = *p;
+    int byte = idx / 8;
+    int bit = idx % 8;
+    if ((legal_bits[byte] & (1 << bit)) == 0) return 0;
   }
   return 1;
 }
 
+int grpc_mdstr_is_legal_header(grpc_mdstr *s) {
+  static const gpr_uint8 legal_header_bits[256 / 8] = {
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0xff, 0x03, 0x00, 0x00, 0x00,
+      0x80, 0xfe, 0xff, 0xff, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+  return conforms_to(s, legal_header_bits);
+}
+
+int grpc_mdstr_is_legal_nonbin_header(grpc_mdstr *s) {
+  static const gpr_uint8 legal_header_bits[256 / 8] = {
+      0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+      0xff, 0xff, 0xff, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+  return conforms_to(s, legal_header_bits);
+}
+
 int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s) {
   /* TODO(ctiller): consider caching this */
   return grpc_is_binary_header((const char *)GPR_SLICE_START_PTR(s->slice),
diff --git a/src/core/transport/metadata.h b/src/core/transport/metadata.h
index 15ef9bb555..eb17747be7 100644
--- a/src/core/transport/metadata.h
+++ b/src/core/transport/metadata.h
@@ -95,7 +95,8 @@ size_t grpc_mdctx_get_mdtab_free_test_only(grpc_mdctx *mdctx);
 
 /* Constructors for grpc_mdstr instances; take a variety of data types that
    clients may have handy */
-grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str, int perform_key_canonicalization);
+grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str,
+                                   int perform_key_canonicalization);
 /* Unrefs the slice. */
 grpc_mdstr *grpc_mdstr_from_slice(grpc_mdctx *ctx, gpr_slice slice);
 grpc_mdstr *grpc_mdstr_from_buffer(grpc_mdctx *ctx, const gpr_uint8 *str,
@@ -153,6 +154,7 @@ void grpc_mdelem_unref(grpc_mdelem *md);
 const char *grpc_mdstr_as_c_string(grpc_mdstr *s);
 
 int grpc_mdstr_is_legal_header(grpc_mdstr *s);
+int grpc_mdstr_is_legal_nonbin_header(grpc_mdstr *s);
 int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
 
 /* Batch mode metadata functions.
@@ -179,4 +181,4 @@ void grpc_mdctx_unlock(grpc_mdctx *ctx);
 
 #define GRPC_MDSTR_KV_HASH(k_hash, v_hash) (GPR_ROTL((k_hash), 2) ^ (v_hash))
 
-#endif  /* GRPC_INTERNAL_CORE_TRANSPORT_METADATA_H */
+#endif /* GRPC_INTERNAL_CORE_TRANSPORT_METADATA_H */
diff --git a/src/core/transport/stream_op.c b/src/core/transport/stream_op.c
index 0a9669b0ab..038586d48e 100644
--- a/src/core/transport/stream_op.c
+++ b/src/core/transport/stream_op.c
@@ -203,8 +203,8 @@ void grpc_metadata_batch_assert_ok(grpc_metadata_batch *batch) {
 #endif /* NDEBUG */
 
 void grpc_metadata_batch_init(grpc_metadata_batch *batch) {
-  batch->list.head = batch->list.tail = batch->garbage.head = batch->garbage.tail =
-      NULL;
+  batch->list.head = batch->list.tail = batch->garbage.head =
+      batch->garbage.tail = NULL;
   batch->deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
 }
 
@@ -288,7 +288,7 @@ void grpc_metadata_batch_merge(grpc_metadata_batch *target,
 }
 
 void grpc_metadata_batch_move(grpc_metadata_batch *dst,
-                               grpc_metadata_batch *src) {
+                              grpc_metadata_batch *src) {
   *dst = *src;
   memset(src, 0, sizeof(grpc_metadata_batch));
 }
diff --git a/src/core/tsi/fake_transport_security.c b/src/core/tsi/fake_transport_security.c
index 9ce1ddb95e..29127c4269 100644
--- a/src/core/tsi/fake_transport_security.c
+++ b/src/core/tsi/fake_transport_security.c
@@ -121,7 +121,7 @@ static void store32_little_endian(gpr_uint32 value, unsigned char* buf) {
   buf[3] = (unsigned char)(value >> 24) & 0xFF;
   buf[2] = (unsigned char)(value >> 16) & 0xFF;
   buf[1] = (unsigned char)(value >> 8) & 0xFF;
-  buf[0] = (unsigned char)(value) & 0xFF;
+  buf[0] = (unsigned char)(value)&0xFF;
 }
 
 static void tsi_fake_frame_reset(tsi_fake_frame* frame, int needs_draining) {
@@ -370,7 +370,8 @@ static void fake_protector_destroy(tsi_frame_protector* self) {
 
 static const tsi_frame_protector_vtable frame_protector_vtable = {
     fake_protector_protect, fake_protector_protect_flush,
-    fake_protector_unprotect, fake_protector_destroy, };
+    fake_protector_unprotect, fake_protector_destroy,
+};
 
 /* --- tsi_handshaker methods implementation. ---*/
 
@@ -393,7 +394,8 @@ static tsi_result fake_handshaker_get_bytes_to_send_to_peer(
       next_message_to_send = TSI_FAKE_HANDSHAKE_MESSAGE_MAX;
     }
     if (tsi_tracing_enabled) {
-      gpr_log(GPR_INFO, "%s prepared %s.", impl->is_client ? "Client" : "Server",
+      gpr_log(GPR_INFO, "%s prepared %s.",
+              impl->is_client ? "Client" : "Server",
               tsi_fake_handshake_message_to_string(impl->next_message_to_send));
     }
     impl->next_message_to_send = next_message_to_send;
@@ -493,7 +495,8 @@ static const tsi_handshaker_vtable handshaker_vtable = {
     fake_handshaker_get_result,
     fake_handshaker_extract_peer,
     fake_handshaker_create_frame_protector,
-    fake_handshaker_destroy, };
+    fake_handshaker_destroy,
+};
 
 tsi_handshaker* tsi_create_fake_handshaker(int is_client) {
   tsi_fake_handshaker* impl = calloc(1, sizeof(tsi_fake_handshaker));
diff --git a/src/core/tsi/fake_transport_security.h b/src/core/tsi/fake_transport_security.h
index af9730b90e..1fa11349fb 100644
--- a/src/core/tsi/fake_transport_security.h
+++ b/src/core/tsi/fake_transport_security.h
@@ -58,4 +58,4 @@ tsi_frame_protector* tsi_create_fake_protector(
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_TSI_FAKE_TRANSPORT_SECURITY_H */
+#endif /* GRPC_INTERNAL_CORE_TSI_FAKE_TRANSPORT_SECURITY_H */
diff --git a/src/core/tsi/ssl_transport_security.c b/src/core/tsi/ssl_transport_security.c
index 609fc06ed5..0b416f6c9d 100644
--- a/src/core/tsi/ssl_transport_security.c
+++ b/src/core/tsi/ssl_transport_security.c
@@ -43,7 +43,7 @@
 #include "src/core/tsi/transport_security.h"
 
 #include <openssl/bio.h>
-#include <openssl/crypto.h>  /* For OPENSSL_free */
+#include <openssl/crypto.h> /* For OPENSSL_free */
 #include <openssl/err.h>
 #include <openssl/ssl.h>
 #include <openssl/x509.h>
@@ -54,7 +54,6 @@
 #define TSI_SSL_MAX_PROTECTED_FRAME_SIZE_UPPER_BOUND 16384
 #define TSI_SSL_MAX_PROTECTED_FRAME_SIZE_LOWER_BOUND 1024
 
-
 /* Putting a macro like this and littering the source file with #if is really
    bad practice.
    TODO(jboeuf): refactor all the #if / #endif in a separate module. */
@@ -116,7 +115,7 @@ typedef struct {
 /* --- Library Initialization. ---*/
 
 static gpr_once init_openssl_once = GPR_ONCE_INIT;
-static gpr_mu *openssl_mutexes = NULL;
+static gpr_mu* openssl_mutexes = NULL;
 
 static void openssl_locking_cb(int mode, int type, const char* file, int line) {
   if (mode & CRYPTO_LOCK) {
@@ -195,7 +194,7 @@ static void ssl_info_callback(const SSL* ssl, int where, int ret) {
 /* Returns 1 if name looks like an IP address, 0 otherwise.
    This is a very rough heuristic as it does not handle IPV6 or things like:
    0300.0250.00.01, 0xC0.0Xa8.0x0.0x1, 000030052000001, 0xc0.052000001 */
-static int looks_like_ip_address(const char *name) {
+static int looks_like_ip_address(const char* name) {
   size_t i;
   size_t dot_count = 0;
   size_t num_size = 0;
@@ -215,7 +214,6 @@ static int looks_like_ip_address(const char *name) {
   return 1;
 }
 
-
 /* Gets the subject CN from an X509 cert. */
 static tsi_result ssl_get_x509_common_name(X509* cert, unsigned char** utf8,
                                            size_t* utf8_size) {
@@ -630,7 +628,8 @@ static tsi_result build_alpn_protocol_name_list(
   }
   /* Safety check. */
   if ((current < *protocol_name_list) ||
-      ((gpr_uintptr)(current - *protocol_name_list) != *protocol_name_list_length)) {
+      ((gpr_uintptr)(current - *protocol_name_list) !=
+       *protocol_name_list_length)) {
     return TSI_INTERNAL_ERROR;
   }
   return TSI_OK;
@@ -768,7 +767,8 @@ static void ssl_protector_destroy(tsi_frame_protector* self) {
 
 static const tsi_frame_protector_vtable frame_protector_vtable = {
     ssl_protector_protect, ssl_protector_protect_flush, ssl_protector_unprotect,
-    ssl_protector_destroy, };
+    ssl_protector_destroy,
+};
 
 /* --- tsi_handshaker methods implementation. ---*/
 
@@ -948,7 +948,8 @@ static const tsi_handshaker_vtable handshaker_vtable = {
     ssl_handshaker_get_result,
     ssl_handshaker_extract_peer,
     ssl_handshaker_create_frame_protector,
-    ssl_handshaker_destroy, };
+    ssl_handshaker_destroy,
+};
 
 /* --- tsi_ssl_handshaker_factory common methods. --- */
 
@@ -1075,9 +1076,11 @@ static void ssl_client_handshaker_factory_destroy(
   free(impl);
 }
 
-static int client_handshaker_factory_npn_callback(
-    SSL* ssl, unsigned char** out, unsigned char* outlen,
-    const unsigned char* in, unsigned int inlen, void* arg) {
+static int client_handshaker_factory_npn_callback(SSL* ssl, unsigned char** out,
+                                                  unsigned char* outlen,
+                                                  const unsigned char* in,
+                                                  unsigned int inlen,
+                                                  void* arg) {
   tsi_ssl_client_handshaker_factory* factory =
       (tsi_ssl_client_handshaker_factory*)arg;
   return select_protocol_list((const unsigned char**)out, outlen,
@@ -1121,7 +1124,7 @@ static void ssl_server_handshaker_factory_destroy(
 
 static int does_entry_match_name(const char* entry, size_t entry_length,
                                  const char* name) {
-  const char *dot;
+  const char* dot;
   const char* name_subdomain = NULL;
   size_t name_length = strlen(name);
   size_t name_subdomain_length;
@@ -1153,7 +1156,7 @@ static int does_entry_match_name(const char* entry, size_t entry_length,
   if (name_subdomain_length < 2) return 0;
   name_subdomain++; /* Starts after the dot. */
   name_subdomain_length--;
-  entry += 2;       /* Remove *. */
+  entry += 2; /* Remove *. */
   entry_length -= 2;
   dot = strchr(name_subdomain, '.');
   if ((dot == NULL) || (dot == &name_subdomain[name_subdomain_length - 1])) {
@@ -1170,7 +1173,7 @@ static int does_entry_match_name(const char* entry, size_t entry_length,
 static int ssl_server_handshaker_factory_servername_callback(SSL* ssl, int* ap,
                                                              void* arg) {
   tsi_ssl_server_handshaker_factory* impl =
-     (tsi_ssl_server_handshaker_factory*)arg;
+      (tsi_ssl_server_handshaker_factory*)arg;
   size_t i = 0;
   const char* servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
   if (servername == NULL || strlen(servername) == 0) {
diff --git a/src/core/tsi/ssl_transport_security.h b/src/core/tsi/ssl_transport_security.h
index 4bf6c81b75..cdf4f294be 100644
--- a/src/core/tsi/ssl_transport_security.h
+++ b/src/core/tsi/ssl_transport_security.h
@@ -170,4 +170,4 @@ int tsi_ssl_peer_matches_name(const tsi_peer* peer, const char* name);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_TSI_SSL_TRANSPORT_SECURITY_H */
+#endif /* GRPC_INTERNAL_CORE_TSI_SSL_TRANSPORT_SECURITY_H */
diff --git a/src/core/tsi/transport_security.h b/src/core/tsi/transport_security.h
index 4cd0ec2cfb..34283f2f9c 100644
--- a/src/core/tsi/transport_security.h
+++ b/src/core/tsi/transport_security.h
@@ -108,4 +108,4 @@ char* tsi_strdup(const char* src); /* Sadly, no strdup in C89. */
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_H */
+#endif /* GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_H */
diff --git a/src/core/tsi/transport_security_interface.h b/src/core/tsi/transport_security_interface.h
index e27e6b9fc9..03a51683a2 100644
--- a/src/core/tsi/transport_security_interface.h
+++ b/src/core/tsi/transport_security_interface.h
@@ -341,4 +341,4 @@ void tsi_handshaker_destroy(tsi_handshaker* self);
 }
 #endif
 
-#endif  /* GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_INTERFACE_H */
+#endif /* GRPC_INTERNAL_CORE_TSI_TRANSPORT_SECURITY_INTERFACE_H */
diff --git a/src/cpp/client/channel.cc b/src/cpp/client/channel.cc
index 0582b59a6d..8bf2e4687e 100644
--- a/src/cpp/client/channel.cc
+++ b/src/cpp/client/channel.cc
@@ -31,29 +31,26 @@
  *
  */
 
-#include "src/cpp/client/channel.h"
+#include <grpc++/channel.h>
 
 #include <memory>
 
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/slice.h>
-
-#include "src/core/profiling/timers.h"
-#include <grpc++/channel_arguments.h>
 #include <grpc++/client_context.h>
 #include <grpc++/completion_queue.h>
-#include <grpc++/config.h>
 #include <grpc++/credentials.h>
 #include <grpc++/impl/call.h>
 #include <grpc++/impl/rpc_method.h>
-#include <grpc++/status.h>
-#include <grpc++/time.h>
+#include <grpc++/support/channel_arguments.h>
+#include <grpc++/support/config.h>
+#include <grpc++/support/status.h>
+#include <grpc++/support/time.h>
+#include "src/core/profiling/timers.h"
 
 namespace grpc {
 
-Channel::Channel(grpc_channel* channel) : c_channel_(channel) {}
-
 Channel::Channel(const grpc::string& host, grpc_channel* channel)
     : host_(host), c_channel_(channel) {}
 
@@ -71,7 +68,7 @@ Call Channel::CreateCall(const RpcMethod& method, ClientContext* context,
   } else {
     const char* host_str = NULL;
     if (!context->authority().empty()) {
-      host_str = context->authority().c_str();
+      host_str = context->authority_.c_str();
     } else if (!host_.empty()) {
       host_str = host_.c_str();
     }
@@ -98,9 +95,8 @@ void Channel::PerformOpsOnCall(CallOpSetInterface* ops, Call* call) {
 }
 
 void* Channel::RegisterMethod(const char* method) {
-  return grpc_channel_register_call(c_channel_, method,
-                                    host_.empty() ? NULL : host_.c_str(),
-                                    nullptr);
+  return grpc_channel_register_call(
+      c_channel_, method, host_.empty() ? NULL : host_.c_str(), nullptr);
 }
 
 grpc_connectivity_state Channel::GetState(bool try_to_connect) {
@@ -117,6 +113,7 @@ class TagSaver GRPC_FINAL : public CompletionQueueTag {
     delete this;
     return true;
   }
+
  private:
   void* tag_;
 };
diff --git a/src/cpp/client/channel_arguments.cc b/src/cpp/client/channel_arguments.cc
index da6602e7af..50422d06c9 100644
--- a/src/cpp/client/channel_arguments.cc
+++ b/src/cpp/client/channel_arguments.cc
@@ -31,10 +31,9 @@
  *
  */
 
-#include <grpc++/channel_arguments.h>
+#include <grpc++/support/channel_arguments.h>
 
 #include <grpc/support/log.h>
-
 #include "src/core/channel/channel_args.h"
 
 namespace grpc {
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index b8caa1eae4..c4d7cf2e51 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -38,7 +38,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc++/credentials.h>
 #include <grpc++/server_context.h>
-#include <grpc++/time.h>
+#include <grpc++/support/time.h>
 
 #include "src/core/channel/compress_filter.h"
 #include "src/cpp/common/create_auth_context.h"
@@ -71,7 +71,7 @@ void ClientContext::AddMetadata(const grpc::string& meta_key,
 }
 
 void ClientContext::set_call(grpc_call* call,
-                             const std::shared_ptr<ChannelInterface>& channel) {
+                             const std::shared_ptr<Channel>& channel) {
   GPR_ASSERT(call_ == nullptr);
   call_ = call;
   channel_ = channel;
diff --git a/src/cpp/client/create_channel.cc b/src/cpp/client/create_channel.cc
index 21d01b739d..8c571cbbaa 100644
--- a/src/cpp/client/create_channel.cc
+++ b/src/cpp/client/create_channel.cc
@@ -34,15 +34,16 @@
 #include <memory>
 #include <sstream>
 
-#include "src/cpp/client/channel.h"
-#include <grpc++/channel_interface.h>
-#include <grpc++/channel_arguments.h>
+#include <grpc++/channel.h>
 #include <grpc++/create_channel.h>
+#include <grpc++/support/channel_arguments.h>
+
+#include "src/cpp/client/create_channel_internal.h"
 
 namespace grpc {
 class ChannelArguments;
 
-std::shared_ptr<ChannelInterface> CreateChannel(
+std::shared_ptr<Channel> CreateChannel(
     const grpc::string& target, const std::shared_ptr<Credentials>& creds,
     const ChannelArguments& args) {
   ChannelArguments cp_args = args;
@@ -50,8 +51,10 @@ std::shared_ptr<ChannelInterface> CreateChannel(
   user_agent_prefix << "grpc-c++/" << grpc_version_string();
   cp_args.SetString(GRPC_ARG_PRIMARY_USER_AGENT_STRING,
                     user_agent_prefix.str());
-  return creds ? creds->CreateChannel(target, cp_args)
-               : std::shared_ptr<ChannelInterface>(
-                     new Channel(grpc_lame_client_channel_create(NULL)));
+  return creds
+             ? creds->CreateChannel(target, cp_args)
+             : CreateChannelInternal("", grpc_lame_client_channel_create(
+                                             NULL, GRPC_STATUS_INVALID_ARGUMENT,
+                                             "Invalid credentials."));
 }
 }  // namespace grpc
diff --git a/src/cpp/client/internal_stub.cc b/src/cpp/client/create_channel_internal.cc
index 91724a4837..9c5ab038cf 100644
--- a/src/cpp/client/internal_stub.cc
+++ b/src/cpp/client/create_channel_internal.cc
@@ -31,6 +31,16 @@
  *
  */
 
-#include <grpc++/impl/internal_stub.h>
+#include <memory>
 
-namespace grpc {}  // namespace grpc
+#include <grpc++/channel.h>
+
+struct grpc_channel;
+
+namespace grpc {
+
+std::shared_ptr<Channel> CreateChannelInternal(const grpc::string& host,
+                                               grpc_channel* c_channel) {
+  return std::shared_ptr<Channel>(new Channel(host, c_channel));
+}
+}  // namespace grpc
diff --git a/src/cpp/client/create_channel_internal.h b/src/cpp/client/create_channel_internal.h
new file mode 100644
index 0000000000..4385ec701e
--- /dev/null
+++ b/src/cpp/client/create_channel_internal.h
@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CPP_CLIENT_CREATE_CHANNEL_INTERNAL_H
+#define GRPC_INTERNAL_CPP_CLIENT_CREATE_CHANNEL_INTERNAL_H
+
+#include <memory>
+
+#include <grpc++/support/config.h>
+
+struct grpc_channel;
+
+namespace grpc {
+class Channel;
+
+std::shared_ptr<Channel> CreateChannelInternal(const grpc::string& host,
+                                               grpc_channel* c_channel);
+
+}  // namespace grpc
+
+#endif  // GRPC_INTERNAL_CPP_CLIENT_CREATE_CHANNEL_INTERNAL_H
diff --git a/src/cpp/client/generic_stub.cc b/src/cpp/client/generic_stub.cc
index 0c90578ae5..7a2fdf941c 100644
--- a/src/cpp/client/generic_stub.cc
+++ b/src/cpp/client/generic_stub.cc
@@ -31,7 +31,7 @@
  *
  */
 
-#include <grpc++/generic_stub.h>
+#include <grpc++/generic/generic_stub.h>
 
 #include <grpc++/impl/rpc_method.h>
 
@@ -44,8 +44,7 @@ std::unique_ptr<GenericClientAsyncReaderWriter> GenericStub::Call(
   return std::unique_ptr<GenericClientAsyncReaderWriter>(
       new GenericClientAsyncReaderWriter(
           channel_.get(), cq,
-          RpcMethod(method.c_str(), RpcMethod::BIDI_STREAMING, nullptr),
-          context, tag));
+          RpcMethod(method.c_str(), RpcMethod::BIDI_STREAMING), context, tag));
 }
 
 }  // namespace grpc
diff --git a/src/cpp/client/insecure_credentials.cc b/src/cpp/client/insecure_credentials.cc
index 2f9357b568..4a4d2cb97d 100644
--- a/src/cpp/client/insecure_credentials.cc
+++ b/src/cpp/client/insecure_credentials.cc
@@ -31,25 +31,27 @@
  *
  */
 
+#include <grpc++/credentials.h>
+
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
-
-#include <grpc++/channel_arguments.h>
-#include <grpc++/config.h>
-#include <grpc++/credentials.h>
-#include "src/cpp/client/channel.h"
+#include <grpc++/channel.h>
+#include <grpc++/support/channel_arguments.h>
+#include <grpc++/support/config.h>
+#include "src/cpp/client/create_channel_internal.h"
 
 namespace grpc {
 
 namespace {
 class InsecureCredentialsImpl GRPC_FINAL : public Credentials {
  public:
-  std::shared_ptr<grpc::ChannelInterface> CreateChannel(
+  std::shared_ptr<grpc::Channel> CreateChannel(
       const string& target, const grpc::ChannelArguments& args) GRPC_OVERRIDE {
     grpc_channel_args channel_args;
     args.SetChannelArgs(&channel_args);
-    return std::shared_ptr<ChannelInterface>(new Channel(
-        grpc_insecure_channel_create(target.c_str(), &channel_args, nullptr)));
+    return CreateChannelInternal(
+        "",
+        grpc_insecure_channel_create(target.c_str(), &channel_args, nullptr));
   }
 
   // InsecureCredentials should not be applied to a call.
diff --git a/src/cpp/client/secure_channel_arguments.cc b/src/cpp/client/secure_channel_arguments.cc
index d89df999ad..e17d3b58b0 100644
--- a/src/cpp/client/secure_channel_arguments.cc
+++ b/src/cpp/client/secure_channel_arguments.cc
@@ -31,9 +31,9 @@
  *
  */
 
-#include <grpc++/channel_arguments.h>
-#include <grpc/grpc_security.h>
+#include <grpc++/support/channel_arguments.h>
 
+#include <grpc/grpc_security.h>
 #include "src/core/channel/channel_args.h"
 
 namespace grpc {
diff --git a/src/cpp/client/secure_credentials.cc b/src/cpp/client/secure_credentials.cc
index 6cd6b77fcf..f368f2590a 100644
--- a/src/cpp/client/secure_credentials.cc
+++ b/src/cpp/client/secure_credentials.cc
@@ -32,21 +32,21 @@
  */
 
 #include <grpc/support/log.h>
-
-#include <grpc++/channel_arguments.h>
+#include <grpc++/channel.h>
 #include <grpc++/impl/grpc_library.h>
-#include "src/cpp/client/channel.h"
+#include <grpc++/support/channel_arguments.h>
+#include "src/cpp/client/create_channel_internal.h"
 #include "src/cpp/client/secure_credentials.h"
 
 namespace grpc {
 
-std::shared_ptr<grpc::ChannelInterface> SecureCredentials::CreateChannel(
+std::shared_ptr<grpc::Channel> SecureCredentials::CreateChannel(
     const string& target, const grpc::ChannelArguments& args) {
   grpc_channel_args channel_args;
   args.SetChannelArgs(&channel_args);
-  return std::shared_ptr<ChannelInterface>(new Channel(
+  return CreateChannelInternal(
       args.GetSslTargetNameOverride(),
-      grpc_secure_channel_create(c_creds_, target.c_str(), &channel_args)));
+      grpc_secure_channel_create(c_creds_, target.c_str(), &channel_args));
 }
 
 bool SecureCredentials::ApplyToCall(grpc_call* call) {
diff --git a/src/cpp/client/secure_credentials.h b/src/cpp/client/secure_credentials.h
index ddf69911b5..62d3185477 100644
--- a/src/cpp/client/secure_credentials.h
+++ b/src/cpp/client/secure_credentials.h
@@ -36,7 +36,7 @@
 
 #include <grpc/grpc_security.h>
 
-#include <grpc++/config.h>
+#include <grpc++/support/config.h>
 #include <grpc++/credentials.h>
 
 namespace grpc {
@@ -48,7 +48,7 @@ class SecureCredentials GRPC_FINAL : public Credentials {
   grpc_credentials* GetRawCreds() { return c_creds_; }
   bool ApplyToCall(grpc_call* call) GRPC_OVERRIDE;
 
-  std::shared_ptr<grpc::ChannelInterface> CreateChannel(
+  std::shared_ptr<grpc::Channel> CreateChannel(
       const string& target, const grpc::ChannelArguments& args) GRPC_OVERRIDE;
   SecureCredentials* AsSecureCredentials() GRPC_OVERRIDE { return this; }
 
@@ -59,4 +59,3 @@ class SecureCredentials GRPC_FINAL : public Credentials {
 }  // namespace grpc
 
 #endif  // GRPC_INTERNAL_CPP_CLIENT_SECURE_CREDENTIALS_H
-
diff --git a/src/cpp/common/auth_property_iterator.cc b/src/cpp/common/auth_property_iterator.cc
index ba88983515..5ccf8cf72c 100644
--- a/src/cpp/common/auth_property_iterator.cc
+++ b/src/cpp/common/auth_property_iterator.cc
@@ -31,7 +31,7 @@
  *
  */
 
-#include <grpc++/auth_context.h>
+#include <grpc++/support/auth_context.h>
 
 #include <grpc/grpc_security.h>
 
@@ -64,8 +64,7 @@ AuthPropertyIterator AuthPropertyIterator::operator++(int) {
   return tmp;
 }
 
-bool AuthPropertyIterator::operator==(
-    const AuthPropertyIterator& rhs) const {
+bool AuthPropertyIterator::operator==(const AuthPropertyIterator& rhs) const {
   if (property_ == nullptr || rhs.property_ == nullptr) {
     return property_ == rhs.property_;
   } else {
@@ -73,8 +72,7 @@ bool AuthPropertyIterator::operator==(
   }
 }
 
-bool AuthPropertyIterator::operator!=(
-    const AuthPropertyIterator& rhs) const {
+bool AuthPropertyIterator::operator!=(const AuthPropertyIterator& rhs) const {
   return !operator==(rhs);
 }
 
diff --git a/src/cpp/common/call.cc b/src/cpp/common/call.cc
index 0a5c976e01..5b87c2a806 100644
--- a/src/cpp/common/call.cc
+++ b/src/cpp/common/call.cc
@@ -34,21 +34,21 @@
 #include <grpc++/impl/call.h>
 
 #include <grpc/support/alloc.h>
-#include <grpc++/byte_buffer.h>
+#include <grpc++/channel.h>
 #include <grpc++/client_context.h>
-#include <grpc++/channel_interface.h>
-
+#include <grpc++/support/byte_buffer.h>
 #include "src/core/profiling/timers.h"
 
 namespace grpc {
 
-void FillMetadataMap(grpc_metadata_array* arr,
-                     std::multimap<grpc::string, grpc::string>* metadata) {
+void FillMetadataMap(
+    grpc_metadata_array* arr,
+    std::multimap<grpc::string_ref, grpc::string_ref>* metadata) {
   for (size_t i = 0; i < arr->count; i++) {
     // TODO(yangg) handle duplicates?
-    metadata->insert(std::pair<grpc::string, grpc::string>(
-        arr->metadata[i].key,
-        grpc::string(arr->metadata[i].value, arr->metadata[i].value_length)));
+    metadata->insert(std::pair<grpc::string_ref, grpc::string_ref>(
+        arr->metadata[i].key, grpc::string_ref(arr->metadata[i].value,
+                                               arr->metadata[i].value_length)));
   }
   grpc_metadata_array_destroy(arr);
   grpc_metadata_array_init(arr);
diff --git a/src/cpp/common/completion_queue.cc b/src/cpp/common/completion_queue.cc
index fca33f8f54..a175beb452 100644
--- a/src/cpp/common/completion_queue.cc
+++ b/src/cpp/common/completion_queue.cc
@@ -36,7 +36,7 @@
 
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
-#include <grpc++/time.h>
+#include <grpc++/support/time.h>
 
 namespace grpc {
 
diff --git a/src/cpp/common/create_auth_context.h b/src/cpp/common/create_auth_context.h
index 9082a90c6d..b4962bae4e 100644
--- a/src/cpp/common/create_auth_context.h
+++ b/src/cpp/common/create_auth_context.h
@@ -33,7 +33,7 @@
 #include <memory>
 
 #include <grpc/grpc.h>
-#include <grpc++/auth_context.h>
+#include <grpc++/support/auth_context.h>
 
 namespace grpc {
 
diff --git a/src/cpp/common/insecure_create_auth_context.cc b/src/cpp/common/insecure_create_auth_context.cc
index 07fc0bd549..fe80c1a80c 100644
--- a/src/cpp/common/insecure_create_auth_context.cc
+++ b/src/cpp/common/insecure_create_auth_context.cc
@@ -33,7 +33,7 @@
 #include <memory>
 
 #include <grpc/grpc.h>
-#include <grpc++/auth_context.h>
+#include <grpc++/support/auth_context.h>
 
 namespace grpc {
 
diff --git a/src/cpp/common/secure_auth_context.h b/src/cpp/common/secure_auth_context.h
index 264ed620a3..01b7126189 100644
--- a/src/cpp/common/secure_auth_context.h
+++ b/src/cpp/common/secure_auth_context.h
@@ -34,7 +34,7 @@
 #ifndef GRPC_INTERNAL_CPP_COMMON_SECURE_AUTH_CONTEXT_H
 #define GRPC_INTERNAL_CPP_COMMON_SECURE_AUTH_CONTEXT_H
 
-#include <grpc++/auth_context.h>
+#include <grpc++/support/auth_context.h>
 
 struct grpc_auth_context;
 
diff --git a/src/cpp/common/secure_create_auth_context.cc b/src/cpp/common/secure_create_auth_context.cc
index d81f4bbc4a..f13d25a1dd 100644
--- a/src/cpp/common/secure_create_auth_context.cc
+++ b/src/cpp/common/secure_create_auth_context.cc
@@ -34,7 +34,7 @@
 
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
-#include <grpc++/auth_context.h>
+#include <grpc++/support/auth_context.h>
 #include "src/cpp/common/secure_auth_context.h"
 
 namespace grpc {
diff --git a/src/cpp/proto/proto_utils.cc b/src/cpp/proto/proto_utils.cc
index 63f4a3a0bc..be84c222a0 100644
--- a/src/cpp/proto/proto_utils.cc
+++ b/src/cpp/proto/proto_utils.cc
@@ -32,7 +32,6 @@
  */
 
 #include <grpc++/impl/proto_utils.h>
-#include <grpc++/config.h>
 
 #include <grpc/grpc.h>
 #include <grpc/byte_buffer.h>
@@ -40,6 +39,7 @@
 #include <grpc/support/slice.h>
 #include <grpc/support/slice_buffer.h>
 #include <grpc/support/port_platform.h>
+#include <grpc++/support/config.h>
 
 const int kMaxBufferLength = 8192;
 
@@ -154,18 +154,18 @@ class GrpcBufferReader GRPC_FINAL
 
 namespace grpc {
 
-Status SerializeProto(const grpc::protobuf::Message& msg, grpc_byte_buffer** bp) {
+Status SerializeProto(const grpc::protobuf::Message& msg,
+                      grpc_byte_buffer** bp) {
   GrpcBufferWriter writer(bp);
   return msg.SerializeToZeroCopyStream(&writer)
              ? Status::OK
-             : Status(StatusCode::INVALID_ARGUMENT,
-                      "Failed to serialize message");
+             : Status(StatusCode::INTERNAL, "Failed to serialize message");
 }
 
 Status DeserializeProto(grpc_byte_buffer* buffer, grpc::protobuf::Message* msg,
                         int max_message_size) {
   if (!buffer) {
-    return Status(StatusCode::INVALID_ARGUMENT, "No payload");
+    return Status(StatusCode::INTERNAL, "No payload");
   }
   GrpcBufferReader reader(buffer);
   ::grpc::protobuf::io::CodedInputStream decoder(&reader);
@@ -173,11 +173,10 @@ Status DeserializeProto(grpc_byte_buffer* buffer, grpc::protobuf::Message* msg,
     decoder.SetTotalBytesLimit(max_message_size, max_message_size);
   }
   if (!msg->ParseFromCodedStream(&decoder)) {
-    return Status(StatusCode::INVALID_ARGUMENT,
-                  msg->InitializationErrorString());
+    return Status(StatusCode::INTERNAL, msg->InitializationErrorString());
   }
   if (!decoder.ConsumedEntireMessage()) {
-    return Status(StatusCode::INVALID_ARGUMENT, "Did not read entire message");
+    return Status(StatusCode::INTERNAL, "Did not read entire message");
   }
   return Status::OK;
 }
diff --git a/src/cpp/server/async_generic_service.cc b/src/cpp/server/async_generic_service.cc
index 2e99afcb5f..6b9ea532b6 100644
--- a/src/cpp/server/async_generic_service.cc
+++ b/src/cpp/server/async_generic_service.cc
@@ -31,7 +31,7 @@
  *
  */
 
-#include <grpc++/async_generic_service.h>
+#include <grpc++/generic/async_generic_service.h>
 
 #include <grpc++/server.h>
 
diff --git a/src/cpp/server/create_default_thread_pool.cc b/src/cpp/server/create_default_thread_pool.cc
index 81c84474d8..f3b07ec8ce 100644
--- a/src/cpp/server/create_default_thread_pool.cc
+++ b/src/cpp/server/create_default_thread_pool.cc
@@ -32,16 +32,17 @@
  */
 
 #include <grpc/support/cpu.h>
-#include <grpc++/dynamic_thread_pool.h>
+
+#include "src/cpp/server/dynamic_thread_pool.h"
 
 #ifndef GRPC_CUSTOM_DEFAULT_THREAD_POOL
 
 namespace grpc {
 
 ThreadPoolInterface* CreateDefaultThreadPool() {
-   int cores = gpr_cpu_num_cores();
-   if (!cores) cores = 4;
-   return new DynamicThreadPool(cores);
+  int cores = gpr_cpu_num_cores();
+  if (!cores) cores = 4;
+  return new DynamicThreadPool(cores);
 }
 
 }  // namespace grpc
diff --git a/src/cpp/server/dynamic_thread_pool.cc b/src/cpp/server/dynamic_thread_pool.cc
index f58d0420df..4b226c2992 100644
--- a/src/cpp/server/dynamic_thread_pool.cc
+++ b/src/cpp/server/dynamic_thread_pool.cc
@@ -33,13 +33,14 @@
 
 #include <grpc++/impl/sync.h>
 #include <grpc++/impl/thd.h>
-#include <grpc++/dynamic_thread_pool.h>
+
+#include "src/cpp/server/dynamic_thread_pool.h"
 
 namespace grpc {
-DynamicThreadPool::DynamicThread::DynamicThread(DynamicThreadPool *pool):
-  pool_(pool),
-  thd_(new grpc::thread(&DynamicThreadPool::DynamicThread::ThreadFunc, this)) {
-}
+DynamicThreadPool::DynamicThread::DynamicThread(DynamicThreadPool* pool)
+    : pool_(pool),
+      thd_(new grpc::thread(&DynamicThreadPool::DynamicThread::ThreadFunc,
+                            this)) {}
 DynamicThreadPool::DynamicThread::~DynamicThread() {
   thd_->join();
   thd_.reset();
@@ -57,7 +58,7 @@ void DynamicThreadPool::DynamicThread::ThreadFunc() {
     pool_->shutdown_cv_.notify_one();
   }
 }
-  
+
 void DynamicThreadPool::ThreadFunc() {
   for (;;) {
     // Wait until work is available or we are shutting down.
@@ -65,7 +66,7 @@ void DynamicThreadPool::ThreadFunc() {
     if (!shutdown_ && callbacks_.empty()) {
       // If there are too many threads waiting, then quit this thread
       if (threads_waiting_ >= reserve_threads_) {
-	break;
+        break;
       }
       threads_waiting_++;
       cv_.wait(lock);
@@ -84,9 +85,11 @@ void DynamicThreadPool::ThreadFunc() {
   }
 }
 
-DynamicThreadPool::DynamicThreadPool(int reserve_threads) :
-  shutdown_(false), reserve_threads_(reserve_threads), nthreads_(0),
-  threads_waiting_(0) {
+DynamicThreadPool::DynamicThreadPool(int reserve_threads)
+    : shutdown_(false),
+      reserve_threads_(reserve_threads),
+      nthreads_(0),
+      threads_waiting_(0) {
   for (int i = 0; i < reserve_threads_; i++) {
     grpc::lock_guard<grpc::mutex> lock(mu_);
     nthreads_++;
@@ -96,10 +99,10 @@ DynamicThreadPool::DynamicThreadPool(int reserve_threads) :
 
 void DynamicThreadPool::ReapThreads(std::list<DynamicThread*>* tlist) {
   for (auto t = tlist->begin(); t != tlist->end(); t = tlist->erase(t)) {
-    delete *t;    
+    delete *t;
   }
 }
-  
+
 DynamicThreadPool::~DynamicThreadPool() {
   grpc::unique_lock<grpc::mutex> lock(mu_);
   shutdown_ = true;
diff --git a/src/cpp/client/channel.h b/src/cpp/server/dynamic_thread_pool.h
index cb8e8d98d2..5ba7533c05 100644
--- a/src/cpp/client/channel.h
+++ b/src/cpp/server/dynamic_thread_pool.h
@@ -31,51 +31,53 @@
  *
  */
 
-#ifndef GRPC_INTERNAL_CPP_CLIENT_CHANNEL_H
-#define GRPC_INTERNAL_CPP_CLIENT_CHANNEL_H
+#ifndef GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
+#define GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
 
+#include <list>
 #include <memory>
+#include <queue>
 
-#include <grpc++/channel_interface.h>
-#include <grpc++/config.h>
-#include <grpc++/impl/grpc_library.h>
+#include <grpc++/impl/sync.h>
+#include <grpc++/impl/thd.h>
+#include <grpc++/support/config.h>
 
-struct grpc_channel;
+#include "src/cpp/server/thread_pool_interface.h"
 
 namespace grpc {
-class Call;
-class CallOpSetInterface;
-class ChannelArguments;
-class CompletionQueue;
-class Credentials;
-class StreamContextInterface;
 
-class Channel GRPC_FINAL : public GrpcLibrary, public ChannelInterface {
+class DynamicThreadPool GRPC_FINAL : public ThreadPoolInterface {
  public:
-  explicit Channel(grpc_channel* c_channel);
-  Channel(const grpc::string& host, grpc_channel* c_channel);
-  ~Channel() GRPC_OVERRIDE;
+  explicit DynamicThreadPool(int reserve_threads);
+  ~DynamicThreadPool();
 
-  void* RegisterMethod(const char* method) GRPC_OVERRIDE;
-  Call CreateCall(const RpcMethod& method, ClientContext* context,
-                          CompletionQueue* cq) GRPC_OVERRIDE;
-  void PerformOpsOnCall(CallOpSetInterface* ops,
-                                Call* call) GRPC_OVERRIDE;
-
-  grpc_connectivity_state GetState(bool try_to_connect) GRPC_OVERRIDE;
+  void Add(const std::function<void()>& callback) GRPC_OVERRIDE;
 
  private:
-  void NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
-                               gpr_timespec deadline, CompletionQueue* cq,
-                               void* tag) GRPC_OVERRIDE;
+  class DynamicThread {
+   public:
+    DynamicThread(DynamicThreadPool* pool);
+    ~DynamicThread();
 
-  bool WaitForStateChangeImpl(grpc_connectivity_state last_observed,
-                              gpr_timespec deadline) GRPC_OVERRIDE;
+   private:
+    DynamicThreadPool* pool_;
+    std::unique_ptr<grpc::thread> thd_;
+    void ThreadFunc();
+  };
+  grpc::mutex mu_;
+  grpc::condition_variable cv_;
+  grpc::condition_variable shutdown_cv_;
+  bool shutdown_;
+  std::queue<std::function<void()>> callbacks_;
+  int reserve_threads_;
+  int nthreads_;
+  int threads_waiting_;
+  std::list<DynamicThread*> dead_threads_;
 
-  const grpc::string host_;
-  grpc_channel* const c_channel_;  // owned
+  void ThreadFunc();
+  static void ReapThreads(std::list<DynamicThread*>* tlist);
 };
 
 }  // namespace grpc
 
-#endif  // GRPC_INTERNAL_CPP_CLIENT_CHANNEL_H
+#endif  // GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
diff --git a/src/cpp/server/fixed_size_thread_pool.cc b/src/cpp/server/fixed_size_thread_pool.cc
index bafbc5802a..2bdc44be2e 100644
--- a/src/cpp/server/fixed_size_thread_pool.cc
+++ b/src/cpp/server/fixed_size_thread_pool.cc
@@ -33,7 +33,7 @@
 
 #include <grpc++/impl/sync.h>
 #include <grpc++/impl/thd.h>
-#include <grpc++/fixed_size_thread_pool.h>
+#include "src/cpp/server/fixed_size_thread_pool.h"
 
 namespace grpc {
 
diff --git a/src/cpp/server/fixed_size_thread_pool.h b/src/cpp/server/fixed_size_thread_pool.h
new file mode 100644
index 0000000000..394ae5821e
--- /dev/null
+++ b/src/cpp/server/fixed_size_thread_pool.h
@@ -0,0 +1,67 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CPP_FIXED_SIZE_THREAD_POOL_H
+#define GRPC_INTERNAL_CPP_FIXED_SIZE_THREAD_POOL_H
+
+#include <queue>
+#include <vector>
+
+#include <grpc++/impl/sync.h>
+#include <grpc++/impl/thd.h>
+#include <grpc++/support/config.h>
+
+#include "src/cpp/server/thread_pool_interface.h"
+
+namespace grpc {
+
+class FixedSizeThreadPool GRPC_FINAL : public ThreadPoolInterface {
+ public:
+  explicit FixedSizeThreadPool(int num_threads);
+  ~FixedSizeThreadPool();
+
+  void Add(const std::function<void()>& callback) GRPC_OVERRIDE;
+
+ private:
+  grpc::mutex mu_;
+  grpc::condition_variable cv_;
+  bool shutdown_;
+  std::queue<std::function<void()>> callbacks_;
+  std::vector<grpc::thread*> threads_;
+
+  void ThreadFunc();
+};
+
+}  // namespace grpc
+
+#endif  // GRPC_INTERNAL_CPP_FIXED_SIZE_THREAD_POOL_H
diff --git a/src/cpp/server/secure_server_credentials.cc b/src/cpp/server/secure_server_credentials.cc
index 32c45e2280..f203cf7f49 100644
--- a/src/cpp/server/secure_server_credentials.cc
+++ b/src/cpp/server/secure_server_credentials.cc
@@ -35,8 +35,8 @@
 
 namespace grpc {
 
-int SecureServerCredentials::AddPortToServer(
-    const grpc::string& addr, grpc_server* server) {
+int SecureServerCredentials::AddPortToServer(const grpc::string& addr,
+                                             grpc_server* server) {
   return grpc_server_add_secure_http2_port(server, addr.c_str(), creds_);
 }
 
diff --git a/src/cpp/server/secure_server_credentials.h b/src/cpp/server/secure_server_credentials.h
index b9803f107e..d3d37b188d 100644
--- a/src/cpp/server/secure_server_credentials.h
+++ b/src/cpp/server/secure_server_credentials.h
@@ -34,10 +34,10 @@
 #ifndef GRPC_INTERNAL_CPP_SERVER_SECURE_SERVER_CREDENTIALS_H
 #define GRPC_INTERNAL_CPP_SERVER_SECURE_SERVER_CREDENTIALS_H
 
-#include <grpc/grpc_security.h>
-
 #include <grpc++/server_credentials.h>
 
+#include <grpc/grpc_security.h>
+
 namespace grpc {
 
 class SecureServerCredentials GRPC_FINAL : public ServerCredentials {
diff --git a/src/cpp/server/server.cc b/src/cpp/server/server.cc
index 90f3854a72..bb83c7d887 100644
--- a/src/cpp/server/server.cc
+++ b/src/cpp/server/server.cc
@@ -32,24 +32,71 @@
  */
 
 #include <grpc++/server.h>
+
 #include <utility>
 
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc++/completion_queue.h>
-#include <grpc++/async_generic_service.h>
+#include <grpc++/generic/async_generic_service.h>
 #include <grpc++/impl/rpc_service_method.h>
 #include <grpc++/impl/service_type.h>
 #include <grpc++/server_context.h>
 #include <grpc++/server_credentials.h>
-#include <grpc++/thread_pool_interface.h>
-#include <grpc++/time.h>
+#include <grpc++/support/time.h>
 
 #include "src/core/profiling/timers.h"
+#include "src/cpp/server/thread_pool_interface.h"
 
 namespace grpc {
 
+class Server::UnimplementedAsyncRequestContext {
+ protected:
+  UnimplementedAsyncRequestContext() : generic_stream_(&server_context_) {}
+
+  GenericServerContext server_context_;
+  GenericServerAsyncReaderWriter generic_stream_;
+};
+
+class Server::UnimplementedAsyncRequest GRPC_FINAL
+    : public UnimplementedAsyncRequestContext,
+      public GenericAsyncRequest {
+ public:
+  UnimplementedAsyncRequest(Server* server, ServerCompletionQueue* cq)
+      : GenericAsyncRequest(server, &server_context_, &generic_stream_, cq, cq,
+                            NULL, false),
+        server_(server),
+        cq_(cq) {}
+
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
+
+  ServerContext* context() { return &server_context_; }
+  GenericServerAsyncReaderWriter* stream() { return &generic_stream_; }
+
+ private:
+  Server* const server_;
+  ServerCompletionQueue* const cq_;
+};
+
+typedef SneakyCallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus>
+    UnimplementedAsyncResponseOp;
+class Server::UnimplementedAsyncResponse GRPC_FINAL
+    : public UnimplementedAsyncResponseOp {
+ public:
+  UnimplementedAsyncResponse(UnimplementedAsyncRequest* request);
+  ~UnimplementedAsyncResponse() { delete request_; }
+
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
+    bool r = UnimplementedAsyncResponseOp::FinalizeResult(tag, status);
+    delete this;
+    return r;
+  }
+
+ private:
+  UnimplementedAsyncRequest* const request_;
+};
+
 class Server::ShutdownRequest GRPC_FINAL : public CompletionQueueTag {
  public:
   bool FinalizeResult(void** tag, bool* status) {
@@ -90,6 +137,26 @@ class Server::SyncRequest GRPC_FINAL : public CompletionQueueTag {
     return mrd;
   }
 
+  static bool AsyncWait(CompletionQueue* cq, SyncRequest** req, bool* ok,
+                        gpr_timespec deadline) {
+    void* tag = nullptr;
+    *ok = false;
+    switch (cq->AsyncNext(&tag, ok, deadline)) {
+      case CompletionQueue::TIMEOUT:
+        *req = nullptr;
+        return true;
+      case CompletionQueue::SHUTDOWN:
+        *req = nullptr;
+        return false;
+      case CompletionQueue::GOT_EVENT:
+        *req = static_cast<SyncRequest*>(tag);
+        GPR_ASSERT((*req)->in_flight_);
+        return true;
+    }
+    gpr_log(GPR_ERROR, "Should never reach here");
+    abort();
+  }
+
   void SetupRequest() { cq_ = grpc_completion_queue_create(nullptr); }
 
   void TeardownRequest() {
@@ -230,18 +297,17 @@ Server::~Server() {
   delete sync_methods_;
 }
 
-bool Server::RegisterService(const grpc::string *host, RpcService* service) {
+bool Server::RegisterService(const grpc::string* host, RpcService* service) {
   for (int i = 0; i < service->GetMethodCount(); ++i) {
     RpcServiceMethod* method = service->GetMethod(i);
-    void* tag = grpc_server_register_method(
-        server_, method->name(), host ? host->c_str() : nullptr);
+    void* tag = grpc_server_register_method(server_, method->name(),
+                                            host ? host->c_str() : nullptr);
     if (!tag) {
       gpr_log(GPR_DEBUG, "Attempt to register %s multiple times",
               method->name());
       return false;
     }
-    SyncRequest request(method, tag);
-    sync_methods_->emplace_back(request);
+    sync_methods_->emplace_back(method, tag);
   }
   return true;
 }
@@ -278,15 +344,23 @@ int Server::AddListeningPort(const grpc::string& addr,
   return creds->AddPortToServer(addr, server_);
 }
 
-bool Server::Start() {
+bool Server::Start(ServerCompletionQueue** cqs, size_t num_cqs) {
   GPR_ASSERT(!started_);
   started_ = true;
   grpc_server_start(server_);
 
   if (!has_generic_service_) {
-    unknown_method_.reset(new RpcServiceMethod(
-        "unknown", RpcMethod::BIDI_STREAMING, new UnknownMethodHandler));
-    sync_methods_->emplace_back(unknown_method_.get(), nullptr);
+    if (!sync_methods_->empty()) {
+      unknown_method_.reset(new RpcServiceMethod(
+          "unknown", RpcMethod::BIDI_STREAMING, new UnknownMethodHandler));
+      // Use of emplace_back with just constructor arguments is not accepted
+      // here by gcc-4.4 because it can't match the anonymous nullptr with a 
+      // proper constructor implicitly. Construct the object and use push_back.
+      sync_methods_->push_back(SyncRequest(unknown_method_.get(), nullptr));
+    }
+    for (size_t i = 0; i < num_cqs; i++) {
+      new UnimplementedAsyncRequest(this, cqs[i]);
+    }
   }
   // Start processing rpcs.
   if (!sync_methods_->empty()) {
@@ -301,12 +375,27 @@ bool Server::Start() {
   return true;
 }
 
-void Server::Shutdown() {
+void Server::ShutdownInternal(gpr_timespec deadline) {
   grpc::unique_lock<grpc::mutex> lock(mu_);
   if (started_ && !shutdown_) {
     shutdown_ = true;
     grpc_server_shutdown_and_notify(server_, cq_.cq(), new ShutdownRequest());
     cq_.Shutdown();
+    // Spin, eating requests until the completion queue is completely shutdown.
+    // If the deadline expires then cancel anything that's pending and keep
+    // spinning forever until the work is actually drained.
+    // Since nothing else needs to touch state guarded by mu_, holding it 
+    // through this loop is fine.
+    SyncRequest* request;
+    bool ok;
+    while (SyncRequest::AsyncWait(&cq_, &request, &ok, deadline)) {
+      if (request == NULL) {  // deadline expired
+        grpc_server_cancel_all_calls(server_);
+        deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+      } else if (ok) {
+        SyncRequest::CallData call_data(this, request);
+      }
+    }
 
     // Wait for running callbacks to finish.
     while (num_running_cb_ != 0) {
@@ -333,12 +422,14 @@ void Server::PerformOpsOnCall(CallOpSetInterface* ops, Call* call) {
 
 Server::BaseAsyncRequest::BaseAsyncRequest(
     Server* server, ServerContext* context,
-    ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag)
+    ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag,
+    bool delete_on_finalize)
     : server_(server),
       context_(context),
       stream_(stream),
       call_cq_(call_cq),
       tag_(tag),
+      delete_on_finalize_(delete_on_finalize),
       call_(nullptr) {
   memset(&initial_metadata_array_, 0, sizeof(initial_metadata_array_));
 }
@@ -348,11 +439,12 @@ Server::BaseAsyncRequest::~BaseAsyncRequest() {}
 bool Server::BaseAsyncRequest::FinalizeResult(void** tag, bool* status) {
   if (*status) {
     for (size_t i = 0; i < initial_metadata_array_.count; i++) {
-      context_->client_metadata_.insert(std::make_pair(
-          grpc::string(initial_metadata_array_.metadata[i].key),
-          grpc::string(initial_metadata_array_.metadata[i].value,
-                       initial_metadata_array_.metadata[i].value +
-                           initial_metadata_array_.metadata[i].value_length)));
+      context_->client_metadata_.insert(
+          std::pair<grpc::string_ref, grpc::string_ref>(
+              initial_metadata_array_.metadata[i].key,
+              grpc::string_ref(
+                  initial_metadata_array_.metadata[i].value,
+                  initial_metadata_array_.metadata[i].value_length)));
     }
   }
   grpc_metadata_array_destroy(&initial_metadata_array_);
@@ -365,14 +457,16 @@ bool Server::BaseAsyncRequest::FinalizeResult(void** tag, bool* status) {
   // just the pointers inside call are copied here
   stream_->BindCall(&call);
   *tag = tag_;
-  delete this;
+  if (delete_on_finalize_) {
+    delete this;
+  }
   return true;
 }
 
 Server::RegisteredAsyncRequest::RegisteredAsyncRequest(
     Server* server, ServerContext* context,
     ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag)
-    : BaseAsyncRequest(server, context, stream, call_cq, tag) {}
+    : BaseAsyncRequest(server, context, stream, call_cq, tag, true) {}
 
 void Server::RegisteredAsyncRequest::IssueRequest(
     void* registered_method, grpc_byte_buffer** payload,
@@ -386,8 +480,9 @@ void Server::RegisteredAsyncRequest::IssueRequest(
 Server::GenericAsyncRequest::GenericAsyncRequest(
     Server* server, GenericServerContext* context,
     ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
-    ServerCompletionQueue* notification_cq, void* tag)
-    : BaseAsyncRequest(server, context, stream, call_cq, tag) {
+    ServerCompletionQueue* notification_cq, void* tag, bool delete_on_finalize)
+    : BaseAsyncRequest(server, context, stream, call_cq, tag,
+                       delete_on_finalize) {
   grpc_call_details_init(&call_details_);
   GPR_ASSERT(notification_cq);
   GPR_ASSERT(call_cq);
@@ -408,6 +503,25 @@ bool Server::GenericAsyncRequest::FinalizeResult(void** tag, bool* status) {
   return BaseAsyncRequest::FinalizeResult(tag, status);
 }
 
+bool Server::UnimplementedAsyncRequest::FinalizeResult(void** tag,
+                                                       bool* status) {
+  if (GenericAsyncRequest::FinalizeResult(tag, status) && *status) {
+    new UnimplementedAsyncRequest(server_, cq_);
+    new UnimplementedAsyncResponse(this);
+  } else {
+    delete this;
+  }
+  return false;
+}
+
+Server::UnimplementedAsyncResponse::UnimplementedAsyncResponse(
+    UnimplementedAsyncRequest* request)
+    : request_(request) {
+  Status status(StatusCode::UNIMPLEMENTED, "");
+  UnknownMethodHandler::FillOps(request_->context(), this);
+  request_->stream()->call_.PerformOps(this);
+}
+
 void Server::ScheduleCallback() {
   {
     grpc::unique_lock<grpc::mutex> lock(mu_);
diff --git a/src/cpp/server/server_builder.cc b/src/cpp/server/server_builder.cc
index 09118879f4..b739cbfe62 100644
--- a/src/cpp/server/server_builder.cc
+++ b/src/cpp/server/server_builder.cc
@@ -37,8 +37,8 @@
 #include <grpc/support/log.h>
 #include <grpc++/impl/service_type.h>
 #include <grpc++/server.h>
-#include <grpc++/thread_pool_interface.h>
-#include <grpc++/fixed_size_thread_pool.h>
+#include "src/cpp/server/thread_pool_interface.h"
+#include "src/cpp/server/fixed_size_thread_pool.h"
 
 namespace grpc {
 
@@ -59,14 +59,16 @@ void ServerBuilder::RegisterAsyncService(AsynchronousService* service) {
   async_services_.emplace_back(new NamedService<AsynchronousService>(service));
 }
 
-void ServerBuilder::RegisterService(
-    const grpc::string& addr, SynchronousService* service) {
-  services_.emplace_back(new NamedService<RpcService>(addr, service->service()));
+void ServerBuilder::RegisterService(const grpc::string& addr,
+                                    SynchronousService* service) {
+  services_.emplace_back(
+      new NamedService<RpcService>(addr, service->service()));
 }
 
-void ServerBuilder::RegisterAsyncService(
-    const grpc::string& addr, AsynchronousService* service) {
-  async_services_.emplace_back(new NamedService<AsynchronousService>(addr, service));
+void ServerBuilder::RegisterAsyncService(const grpc::string& addr,
+                                         AsynchronousService* service) {
+  async_services_.emplace_back(
+      new NamedService<AsynchronousService>(addr, service));
 }
 
 void ServerBuilder::RegisterAsyncGenericService(AsyncGenericService* service) {
@@ -87,10 +89,6 @@ void ServerBuilder::AddListeningPort(const grpc::string& addr,
   ports_.push_back(port);
 }
 
-void ServerBuilder::SetThreadPool(ThreadPoolInterface* thread_pool) {
-  thread_pool_ = thread_pool;
-}
-
 std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
   bool thread_pool_owned = false;
   if (!async_services_.empty() && !services_.empty()) {
@@ -101,12 +99,6 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
     thread_pool_ = CreateDefaultThreadPool();
     thread_pool_owned = true;
   }
-  // Async services only, create a thread pool to handle requests to unknown
-  // services.
-  if (!thread_pool_ && !generic_service_ && !async_services_.empty()) {
-    thread_pool_ = new FixedSizeThreadPool(1);
-    thread_pool_owned = true;
-  }
   std::unique_ptr<Server> server(
       new Server(thread_pool_, thread_pool_owned, max_message_size_));
   for (auto cq = cqs_.begin(); cq != cqs_.end(); ++cq) {
@@ -119,9 +111,10 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
       return nullptr;
     }
   }
-  for (auto service = async_services_.begin();
-       service != async_services_.end(); service++) {
-    if (!server->RegisterAsyncService((*service)->host.get(), (*service)->service)) {
+  for (auto service = async_services_.begin(); service != async_services_.end();
+       service++) {
+    if (!server->RegisterAsyncService((*service)->host.get(),
+                                      (*service)->service)) {
       return nullptr;
     }
   }
@@ -135,7 +128,7 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
       *port->selected_port = r;
     }
   }
-  if (!server->Start()) {
+  if (!server->Start(&cqs_[0], cqs_.size())) {
     return nullptr;
   }
   return server;
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index bb34040a2f..8193e70660 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -38,7 +38,7 @@
 #include <grpc/support/log.h>
 #include <grpc++/impl/call.h>
 #include <grpc++/impl/sync.h>
-#include <grpc++/time.h>
+#include <grpc++/support/time.h>
 
 #include "src/core/channel/compress_filter.h"
 #include "src/cpp/common/create_auth_context.h"
@@ -50,7 +50,12 @@ namespace grpc {
 class ServerContext::CompletionOp GRPC_FINAL : public CallOpSetInterface {
  public:
   // initial refs: one in the server context, one in the cq
-  CompletionOp() : has_tag_(false), tag_(nullptr), refs_(2), finalized_(false), cancelled_(0) {}
+  CompletionOp()
+      : has_tag_(false),
+        tag_(nullptr),
+        refs_(2),
+        finalized_(false),
+        cancelled_(0) {}
 
   void FillOps(grpc_op* ops, size_t* nops) GRPC_OVERRIDE;
   bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
@@ -131,10 +136,9 @@ ServerContext::ServerContext(gpr_timespec deadline, grpc_metadata* metadata,
       cq_(nullptr),
       sent_initial_metadata_(false) {
   for (size_t i = 0; i < metadata_count; i++) {
-    client_metadata_.insert(std::make_pair(
-        grpc::string(metadata[i].key),
-        grpc::string(metadata[i].value,
-                     metadata[i].value + metadata[i].value_length)));
+    client_metadata_.insert(std::pair<grpc::string_ref, grpc::string_ref>(
+        metadata[i].key,
+        grpc::string_ref(metadata[i].value, metadata[i].value_length)));
   }
 }
 
diff --git a/src/cpp/server/thread_pool_interface.h b/src/cpp/server/thread_pool_interface.h
new file mode 100644
index 0000000000..1ebe30fe2a
--- /dev/null
+++ b/src/cpp/server/thread_pool_interface.h
@@ -0,0 +1,54 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CPP_THREAD_POOL_INTERFACE_H
+#define GRPC_INTERNAL_CPP_THREAD_POOL_INTERFACE_H
+
+#include <functional>
+
+namespace grpc {
+
+// A thread pool interface for running callbacks.
+class ThreadPoolInterface {
+ public:
+  virtual ~ThreadPoolInterface() {}
+
+  // Schedule the given callback for execution.
+  virtual void Add(const std::function<void()>& callback) = 0;
+};
+
+ThreadPoolInterface* CreateDefaultThreadPool();
+
+}  // namespace grpc
+
+#endif  // GRPC_INTERNAL_CPP_THREAD_POOL_INTERFACE_H
diff --git a/src/cpp/util/byte_buffer.cc b/src/cpp/util/byte_buffer.cc
index a66c92c3e1..e46e656beb 100644
--- a/src/cpp/util/byte_buffer.cc
+++ b/src/cpp/util/byte_buffer.cc
@@ -32,7 +32,7 @@
  */
 
 #include <grpc/byte_buffer_reader.h>
-#include <grpc++/byte_buffer.h>
+#include <grpc++/support/byte_buffer.h>
 
 namespace grpc {
 
diff --git a/src/cpp/util/slice.cc b/src/cpp/util/slice.cc
index 57370dabc6..7e88423b6c 100644
--- a/src/cpp/util/slice.cc
+++ b/src/cpp/util/slice.cc
@@ -31,7 +31,7 @@
  *
  */
 
-#include <grpc++/slice.h>
+#include <grpc++/support/slice.h>
 
 namespace grpc {
 
diff --git a/src/cpp/util/status.cc b/src/cpp/util/status.cc
index 5bb9eda3d9..ad9850cf07 100644
--- a/src/cpp/util/status.cc
+++ b/src/cpp/util/status.cc
@@ -31,7 +31,7 @@
  *
  */
 
-#include <grpc++/status.h>
+#include <grpc++/support/status.h>
 
 namespace grpc {
 
diff --git a/src/cpp/util/string_ref.cc b/src/cpp/util/string_ref.cc
new file mode 100644
index 0000000000..d9c9019da8
--- /dev/null
+++ b/src/cpp/util/string_ref.cc
@@ -0,0 +1,111 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc++/support/string_ref.h>
+
+#include <string.h>
+
+#include <algorithm>
+
+namespace grpc {
+
+const size_t string_ref::npos;
+
+string_ref& string_ref::operator=(const string_ref& rhs) {
+  data_ = rhs.data_;
+  length_ = rhs.length_;
+  return *this;
+}
+
+string_ref::string_ref(const char* s) : data_(s), length_(strlen(s)) {}
+
+string_ref string_ref::substr(size_t pos, size_t n) const {
+  if (pos > length_) pos = length_;
+  if (n > (length_ - pos)) n = length_ - pos;
+  return string_ref(data_ + pos, n);
+}
+
+int string_ref::compare(string_ref x) const {
+  size_t min_size = length_ < x.length_ ? length_ : x.length_;
+  int r = memcmp(data_, x.data_, min_size);
+  if (r < 0) return -1;
+  if (r > 0) return 1;
+  if (length_ < x.length_) return -1;
+  if (length_ > x.length_) return 1;
+  return 0;
+}
+
+bool string_ref::starts_with(string_ref x) const {
+  return length_ >= x.length_ && (memcmp(data_, x.data_, x.length_) == 0);
+}
+
+bool string_ref::ends_with(string_ref x) const {
+  return length_ >= x.length_ &&
+         (memcmp(data_ + (length_ - x.length_), x.data_, x.length_) == 0);
+}
+
+size_t string_ref::find(string_ref s) const {
+  auto it = std::search(cbegin(), cend(), s.cbegin(), s.cend());
+  return it == cend() ? npos : std::distance(cbegin(), it);
+}
+
+size_t string_ref::find(char c) const {
+  auto it = std::find_if(cbegin(), cend(), [c](char cc) { return cc == c; });
+  return it == cend() ? npos : std::distance(cbegin(), it);
+}
+
+bool operator==(string_ref x, string_ref y) {
+  return x.compare(y) == 0;
+}
+
+bool operator!=(string_ref x, string_ref y) {
+  return x.compare(y) != 0;
+}
+
+bool operator<(string_ref x, string_ref y) {
+  return x.compare(y) < 0;
+}
+
+bool operator<=(string_ref x, string_ref y) {
+  return x.compare(y) <= 0;
+}
+
+bool operator>(string_ref x, string_ref y) {
+  return x.compare(y) > 0;
+}
+
+bool operator>=(string_ref x, string_ref y) {
+  return x.compare(y) >= 0;
+}
+
+}  // namespace grpc
diff --git a/src/cpp/util/time.cc b/src/cpp/util/time.cc
index 799c597e0b..b3401eb26b 100644
--- a/src/cpp/util/time.cc
+++ b/src/cpp/util/time.cc
@@ -31,12 +31,12 @@
  *
  */
 
-#include <grpc++/config.h>
+#include <grpc++/support/config.h>
 
 #ifndef GRPC_CXX0X_NO_CHRONO
 
 #include <grpc/support/time.h>
-#include <grpc++/time.h>
+#include <grpc++/support/time.h>
 
 using std::chrono::duration_cast;
 using std::chrono::nanoseconds;
diff --git a/src/csharp/.gitignore b/src/csharp/.gitignore
index ae48956567..48365e32a5 100644
--- a/src/csharp/.gitignore
+++ b/src/csharp/.gitignore
@@ -5,4 +5,5 @@ test-results
 packages
 Grpc.v12.suo
 TestResult.xml
+/TestResults
 *.nupkg
diff --git a/src/csharp/Grpc.Auth/AuthInterceptors.cs b/src/csharp/Grpc.Auth/AuthInterceptors.cs
new file mode 100644
index 0000000000..c8ab4d9af6
--- /dev/null
+++ b/src/csharp/Grpc.Auth/AuthInterceptors.cs
@@ -0,0 +1,88 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Threading;
+
+using Google.Apis.Auth.OAuth2;
+using Grpc.Core;
+using Grpc.Core.Utils;
+
+namespace Grpc.Auth
+{
+    /// <summary>
+    /// Factory methods to create authorization interceptors. Interceptors created can be registered with gRPC client classes (autogenerated client stubs that
+    /// inherit from <see cref="Grpc.Core.ClientBase"/>).
+    /// </summary>
+    public static class AuthInterceptors
+    {
+        private const string AuthorizationHeader = "Authorization";
+        private const string Schema = "Bearer";
+
+        /// <summary>
+        /// Creates interceptor that will obtain access token from any credential type that implements
+        /// <c>ITokenAccess</c>. (e.g. <c>GoogleCredential</c>).
+        /// </summary>
+        /// <param name="credential">The credential to use to obtain access tokens.</param>
+        /// <returns>The header interceptor.</returns>
+        public static HeaderInterceptor FromCredential(ITokenAccess credential)
+        {
+            return new HeaderInterceptor((method, authUri, metadata) =>
+            {
+                // TODO(jtattermusch): Rethink synchronous wait to obtain the result.
+                var accessToken = credential.GetAccessTokenForRequestAsync(authUri, CancellationToken.None)
+                        .ConfigureAwait(false).GetAwaiter().GetResult();
+                metadata.Add(CreateBearerTokenHeader(accessToken));
+            });
+        }
+
+        /// <summary>
+        /// Creates OAuth2 interceptor that will use given access token as authorization.
+        /// </summary>
+        /// <param name="accessToken">OAuth2 access token.</param>
+        /// <returns>The header interceptor.</returns>
+        public static HeaderInterceptor FromAccessToken(string accessToken)
+        {
+            Preconditions.CheckNotNull(accessToken);
+            return new HeaderInterceptor((method, authUri, metadata) =>
+            {
+                metadata.Add(CreateBearerTokenHeader(accessToken));
+            });
+        }
+
+        private static Metadata.Entry CreateBearerTokenHeader(string accessToken)
+        {
+            return new Metadata.Entry(AuthorizationHeader, Schema + " " + accessToken);
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Auth/Grpc.Auth.csproj b/src/csharp/Grpc.Auth/Grpc.Auth.csproj
index 930a34b0c3..4fb087d4a3 100644
--- a/src/csharp/Grpc.Auth/Grpc.Auth.csproj
+++ b/src/csharp/Grpc.Auth/Grpc.Auth.csproj
@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{AE21D0EE-9A2C-4C15-AB7F-5224EED5B0EA}</ProjectGuid>
     <OutputType>Library</OutputType>
     <RootNamespace>Grpc.Auth</RootNamespace>
@@ -41,57 +39,47 @@
     <AssemblyOriginatorKeyFile>C:\keys\Grpc.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="BouncyCastle.Crypto, Version=1.7.4137.9688, Culture=neutral, PublicKeyToken=a4292a325f69b123, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="System" />
+    <Reference Include="System.Net" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Net.Http.WebRequest" />
+    <Reference Include="BouncyCastle.Crypto">
       <HintPath>..\packages\BouncyCastle.1.7.0\lib\Net40-Client\BouncyCastle.Crypto.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Auth, Version=1.9.3.19379, Culture=neutral, PublicKeyToken=4b01fa6e34db77ab, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Google.Apis.Auth">
       <HintPath>..\packages\Google.Apis.Auth.1.9.3\lib\net40\Google.Apis.Auth.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Auth.PlatformServices, Version=1.9.3.19383, Culture=neutral, PublicKeyToken=4b01fa6e34db77ab, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Google.Apis.Auth.PlatformServices">
       <HintPath>..\packages\Google.Apis.Auth.1.9.3\lib\net40\Google.Apis.Auth.PlatformServices.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Core, Version=1.9.3.19379, Culture=neutral, PublicKeyToken=4b01fa6e34db77ab, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Google.Apis.Core">
       <HintPath>..\packages\Google.Apis.Core.1.9.3\lib\portable-net40+sl50+win+wpa81+wp80\Google.Apis.Core.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Microsoft.Threading.Tasks">
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks.Extensions, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions">
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop, Version=1.0.168.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop">
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.Desktop.dll</HintPath>
     </Reference>
-    <Reference Include="Newtonsoft.Json, Version=7.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Newtonsoft.Json">
       <HintPath>..\packages\Newtonsoft.Json.7.0.1\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
-    <Reference Include="System" />
-    <Reference Include="System.Net" />
-    <Reference Include="System.Net.Http" />
-    <Reference Include="System.Net.Http.Extensions, Version=2.2.29.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="System.Net.Http.Extensions">
       <HintPath>..\packages\Microsoft.Net.Http.2.2.29\lib\net45\System.Net.Http.Extensions.dll</HintPath>
     </Reference>
-    <Reference Include="System.Net.Http.Primitives, Version=4.2.29.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="System.Net.Http.Primitives">
       <HintPath>..\packages\Microsoft.Net.Http.2.2.29\lib\net45\System.Net.Http.Primitives.dll</HintPath>
     </Reference>
-    <Reference Include="System.Net.Http.WebRequest" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Grpc.Core\Version.cs">
       <Link>Version.cs</Link>
     </Compile>
     <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="OAuth2Interceptors.cs" />
+    <Compile Include="AuthInterceptors.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
diff --git a/src/csharp/Grpc.Auth/Grpc.Auth.nuspec b/src/csharp/Grpc.Auth/Grpc.Auth.nuspec
index 2dc10d24c2..f1f8f7c709 100644
--- a/src/csharp/Grpc.Auth/Grpc.Auth.nuspec
+++ b/src/csharp/Grpc.Auth/Grpc.Auth.nuspec
@@ -15,7 +15,7 @@
     <copyright>Copyright 2015, Google Inc.</copyright>
     <tags>gRPC RPC Protocol HTTP/2 Auth OAuth2</tags>
 	<dependencies>
-	  <dependency id="Google.Apis.Auth" version="1.9.2" />
+	  <dependency id="Google.Apis.Auth" version="1.9.3" />
 	  <dependency id="Grpc.Core" version="$version$" />
     </dependencies>
   </metadata>
diff --git a/src/csharp/Grpc.Auth/OAuth2Interceptors.cs b/src/csharp/Grpc.Auth/OAuth2Interceptors.cs
deleted file mode 100644
index d628a83246..0000000000
--- a/src/csharp/Grpc.Auth/OAuth2Interceptors.cs
+++ /dev/null
@@ -1,115 +0,0 @@
-#region Copyright notice and license
-
-// Copyright 2015, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#endregion
-
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.IO;
-using System.Security.Cryptography.X509Certificates;
-using System.Text.RegularExpressions;
-using System.Threading;
-using System.Threading.Tasks;
-
-using Google.Apis.Auth.OAuth2;
-using Google.Apis.Util;
-using Grpc.Core;
-using Grpc.Core.Utils;
-
-namespace Grpc.Auth
-{
-    public static class OAuth2Interceptors
-    {
-        /// <summary>
-        /// Creates OAuth2 interceptor that will obtain access token from GoogleCredentials.
-        /// </summary>
-        public static MetadataInterceptorDelegate FromCredential(GoogleCredential googleCredential)
-        {
-            var interceptor = new OAuth2Interceptor(googleCredential, SystemClock.Default);
-            return new MetadataInterceptorDelegate(interceptor.InterceptHeaders);
-        }
-
-        /// <summary>
-        /// Creates OAuth2 interceptor that will use given OAuth2 token.
-        /// </summary>
-        /// <param name="oauth2Token"></param>
-        /// <returns></returns>
-        public static MetadataInterceptorDelegate FromAccessToken(string oauth2Token)
-        {
-            Preconditions.CheckNotNull(oauth2Token);
-            return new MetadataInterceptorDelegate((authUri, metadata) =>
-            {
-                metadata.Add(OAuth2Interceptor.CreateBearerTokenHeader(oauth2Token));
-            });
-        }
-
-        /// <summary>
-        /// Injects OAuth2 authorization header into initial metadata (= request headers).
-        /// </summary>
-        private class OAuth2Interceptor
-        {
-            private const string AuthorizationHeader = "Authorization";
-            private const string Schema = "Bearer";
-
-            private ITokenAccess credential;
-            private IClock clock;
-
-            public OAuth2Interceptor(ITokenAccess credential, IClock clock)
-            {
-                this.credential = credential;
-                this.clock = clock;
-            }
-
-            /// <summary>
-            /// Gets access token and requests refreshing it if is going to expire soon.
-            /// </summary>
-            /// <param name="cancellationToken"></param>
-            /// <returns></returns>
-            public string GetAccessToken(string authUri, CancellationToken cancellationToken)
-            {
-                // TODO(jtattermusch): Rethink synchronous wait to obtain the result.
-                return credential.GetAccessTokenForRequestAsync(authUri, cancellationToken: cancellationToken).GetAwaiter().GetResult();
-            }
-
-            public void InterceptHeaders(string authUri, Metadata metadata)
-            {
-                var accessToken = GetAccessToken(authUri, CancellationToken.None);
-                metadata.Add(CreateBearerTokenHeader(accessToken));
-            }
-
-            public static Metadata.Entry CreateBearerTokenHeader(string accessToken)
-            {
-                return new Metadata.Entry(AuthorizationHeader, Schema + " " + accessToken);
-            }
-        }
-    }
-}
diff --git a/src/csharp/Grpc.Core.Tests/ChannelTest.cs b/src/csharp/Grpc.Core.Tests/ChannelTest.cs
index 2787572924..dfbd92879e 100644
--- a/src/csharp/Grpc.Core.Tests/ChannelTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ChannelTest.cs
@@ -41,12 +41,6 @@ namespace Grpc.Core.Tests
 {
     public class ChannelTest
     {
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void Constructor_RejectsInvalidParams()
         {
@@ -56,36 +50,33 @@ namespace Grpc.Core.Tests
         [Test]
         public void State_IdleAfterCreation()
         {
-            using (var channel = new Channel("localhost", Credentials.Insecure))
-            {
-                Assert.AreEqual(ChannelState.Idle, channel.State);
-            }
+            var channel = new Channel("localhost", Credentials.Insecure);
+            Assert.AreEqual(ChannelState.Idle, channel.State);
+            channel.ShutdownAsync().Wait();
         }
 
         [Test]
         public void WaitForStateChangedAsync_InvalidArgument()
         {
-            using (var channel = new Channel("localhost", Credentials.Insecure))
-            {
-                Assert.Throws(typeof(ArgumentException), () => channel.WaitForStateChangedAsync(ChannelState.FatalFailure));
-            }
+            var channel = new Channel("localhost", Credentials.Insecure);
+            Assert.Throws(typeof(ArgumentException), () => channel.WaitForStateChangedAsync(ChannelState.FatalFailure));
+            channel.ShutdownAsync().Wait();
         }
 
         [Test]
         public void ResolvedTarget()
         {
-            using (var channel = new Channel("127.0.0.1", Credentials.Insecure))
-            {
-                Assert.IsTrue(channel.ResolvedTarget.Contains("127.0.0.1"));
-            }
+            var channel = new Channel("127.0.0.1", Credentials.Insecure);
+            Assert.IsTrue(channel.ResolvedTarget.Contains("127.0.0.1"));
+            channel.ShutdownAsync().Wait();
         }
 
         [Test]
-        public void Dispose_IsIdempotent()
+        public void Shutdown_AllowedOnlyOnce()
         {
             var channel = new Channel("localhost", Credentials.Insecure);
-            channel.Dispose();
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
+            Assert.Throws(typeof(InvalidOperationException), () => channel.ShutdownAsync().GetAwaiter().GetResult());
         }
     }
 }
diff --git a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
index e49fdb5268..68279a2007 100644
--- a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
@@ -63,16 +63,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public async Task UnaryCall()
         {
@@ -208,13 +202,6 @@ namespace Grpc.Core.Tests
         }
 
         [Test]
-        public void UnaryCall_DisposedChannel()
-        {
-            channel.Dispose();
-            Assert.Throws(typeof(ObjectDisposedException), () => Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "ABC"));
-        }
-
-        [Test]
         public void UnaryCallPerformance()
         {
             helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
diff --git a/src/csharp/Grpc.Core.Tests/CompressionTest.cs b/src/csharp/Grpc.Core.Tests/CompressionTest.cs
index 9547683f60..378c81851c 100644
--- a/src/csharp/Grpc.Core.Tests/CompressionTest.cs
+++ b/src/csharp/Grpc.Core.Tests/CompressionTest.cs
@@ -62,16 +62,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void WriteOptions_Unary()
         {
diff --git a/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs b/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs
index db5f953b0e..2db3f286f7 100644
--- a/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs
@@ -62,16 +62,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public async Task PropagateCancellation()
         {
diff --git a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
index d6a8f52570..b571fe9025 100644
--- a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
+++ b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
@@ -64,6 +64,8 @@
       <Link>Version.cs</Link>
     </Compile>
     <Compile Include="ClientBaseTest.cs" />
+    <Compile Include="ShutdownTest.cs" />
+    <Compile Include="Internal\AsyncCallTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ClientServerTest.cs" />
     <Compile Include="ServerTest.cs" />
@@ -82,6 +84,7 @@
     <Compile Include="ResponseHeadersTest.cs" />
     <Compile Include="CompressionTest.cs" />
     <Compile Include="ContextPropagationTest.cs" />
+    <Compile Include="MetadataTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
diff --git a/src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs b/src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs
index 4ed93c7eca..78295cf6d4 100644
--- a/src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs
+++ b/src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs
@@ -43,31 +43,40 @@ namespace Grpc.Core.Tests
         [Test]
         public void InitializeAndShutdownGrpcEnvironment()
         {
-            var env = GrpcEnvironment.GetInstance();
+            var env = GrpcEnvironment.AddRef();
             Assert.IsNotNull(env.CompletionQueue);
-            GrpcEnvironment.Shutdown();
+            GrpcEnvironment.Release();
         }
 
         [Test]
         public void SubsequentInvocations()
         {
-            var env1 = GrpcEnvironment.GetInstance();
-            var env2 = GrpcEnvironment.GetInstance();
-            Assert.IsTrue(object.ReferenceEquals(env1, env2));
-            GrpcEnvironment.Shutdown();
-            GrpcEnvironment.Shutdown();
+            var env1 = GrpcEnvironment.AddRef();
+            var env2 = GrpcEnvironment.AddRef();
+            Assert.AreSame(env1, env2);
+            GrpcEnvironment.Release();
+            GrpcEnvironment.Release();
         }
 
         [Test]
         public void InitializeAfterShutdown()
         {
-            var env1 = GrpcEnvironment.GetInstance();
-            GrpcEnvironment.Shutdown();
+            Assert.AreEqual(0, GrpcEnvironment.GetRefCount());
 
-            var env2 = GrpcEnvironment.GetInstance();
-            GrpcEnvironment.Shutdown();
+            var env1 = GrpcEnvironment.AddRef();
+            GrpcEnvironment.Release();
 
-            Assert.IsFalse(object.ReferenceEquals(env1, env2));
+            var env2 = GrpcEnvironment.AddRef();
+            GrpcEnvironment.Release();
+
+            Assert.AreNotSame(env1, env2);
+        }
+
+        [Test]
+        public void ReleaseWithoutAddRef()
+        {
+            Assert.AreEqual(0, GrpcEnvironment.GetRefCount());
+            Assert.Throws(typeof(InvalidOperationException), () => GrpcEnvironment.Release());
         }
 
         [Test]
diff --git a/src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs b/src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs
new file mode 100644
index 0000000000..685c5f7d6c
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs
@@ -0,0 +1,222 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+
+using Grpc.Core.Internal;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class AsyncCallTest
+    {
+        Channel channel;
+        FakeNativeCall fakeCall;
+        AsyncCall<string, string> asyncCall;
+
+        [SetUp]
+        public void Init()
+        {
+            channel = new Channel("localhost", Credentials.Insecure);
+
+            fakeCall = new FakeNativeCall();
+
+            var callDetails = new CallInvocationDetails<string, string>(channel, "someMethod", null, Marshallers.StringMarshaller, Marshallers.StringMarshaller, new CallOptions());
+            asyncCall = new AsyncCall<string, string>(callDetails, fakeCall);
+        }
+
+        [TearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+        }
+
+        [Test]
+        public void AsyncUnary_CompletionSuccess()
+        {
+            var resultTask = asyncCall.UnaryCallAsync("abc");
+            fakeCall.UnaryResponseClientHandler(true, new ClientSideStatus(Status.DefaultSuccess, new Metadata()), new byte[] { 1, 2, 3 }, new Metadata());
+            Assert.IsTrue(resultTask.IsCompleted);
+            Assert.IsTrue(fakeCall.IsDisposed);
+            Assert.AreEqual(Status.DefaultSuccess, asyncCall.GetStatus());
+        }
+
+        [Test]
+        public void AsyncUnary_CompletionFailure()
+        {
+            var resultTask = asyncCall.UnaryCallAsync("abc");
+            fakeCall.UnaryResponseClientHandler(false, new ClientSideStatus(new Status(StatusCode.Internal, ""), null), new byte[] { 1, 2, 3 }, new Metadata());
+
+            Assert.IsTrue(resultTask.IsCompleted);
+            Assert.IsTrue(fakeCall.IsDisposed);
+
+            Assert.AreEqual(StatusCode.Internal, asyncCall.GetStatus().StatusCode);
+            Assert.IsNull(asyncCall.GetTrailers());
+            var ex = Assert.Throws<RpcException>(() => resultTask.GetAwaiter().GetResult());
+            Assert.AreEqual(StatusCode.Internal, ex.Status.StatusCode);
+        }
+
+        internal class FakeNativeCall : INativeCall
+        {
+            public UnaryResponseClientHandler UnaryResponseClientHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedStatusOnClientHandler ReceivedStatusOnClientHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedMessageHandler ReceivedMessageHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedResponseHeadersHandler ReceivedResponseHeadersHandler
+            {
+                get;
+                set;
+            }
+
+            public SendCompletionHandler SendCompletionHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedCloseOnServerHandler ReceivedCloseOnServerHandler
+            {
+                get;
+                set;
+            }
+
+            public bool IsCancelled
+            {
+                get;
+                set;
+            }
+
+            public bool IsDisposed
+            {
+                get;
+                set;
+            }
+
+            public void Cancel()
+            {
+                IsCancelled = true;
+            }
+
+            public void CancelWithStatus(Status status)
+            {
+                IsCancelled = true;
+            }
+
+            public string GetPeer()
+            {
+                return "PEER";
+            }
+
+            public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                UnaryResponseClientHandler = callback;
+            }
+
+            public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                UnaryResponseClientHandler = callback;
+            }
+
+            public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                ReceivedStatusOnClientHandler = callback;
+            }
+
+            public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                ReceivedStatusOnClientHandler = callback;
+            }
+
+            public void StartReceiveMessage(ReceivedMessageHandler callback)
+            {
+                ReceivedMessageHandler = callback;
+            }
+
+            public void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback)
+            {
+                ReceivedResponseHeadersHandler = callback;
+            }
+
+            public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendCloseFromClient(SendCompletionHandler callback)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartServerSide(ReceivedCloseOnServerHandler callback)
+            {
+                ReceivedCloseOnServerHandler = callback;
+            }
+
+            public void Dispose()
+            {
+                IsDisposed = true;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/csharp/Grpc.Core.Tests/MetadataTest.cs b/src/csharp/Grpc.Core.Tests/MetadataTest.cs
new file mode 100644
index 0000000000..c00f945d6a
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/MetadataTest.cs
@@ -0,0 +1,120 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class MetadataTest
+    {
+        [Test]
+        public void AsciiEntry()
+        {
+            var entry = new Metadata.Entry("ABC", "XYZ");
+            Assert.IsFalse(entry.IsBinary);
+            Assert.AreEqual("abc", entry.Key);  // key is in lowercase.
+            Assert.AreEqual("XYZ", entry.Value);
+            CollectionAssert.AreEqual(new[] { (byte)'X', (byte)'Y', (byte)'Z' }, entry.ValueBytes);
+
+            Assert.Throws(typeof(ArgumentException), () => new Metadata.Entry("abc-bin", "xyz"));
+
+            Assert.AreEqual("[Entry: key=abc, value=XYZ]", entry.ToString());
+        }
+
+        [Test]
+        public void BinaryEntry()
+        {
+            var bytes = new byte[] { 1, 2, 3 };
+            var entry = new Metadata.Entry("ABC-BIN", bytes);
+            Assert.IsTrue(entry.IsBinary);
+            Assert.AreEqual("abc-bin", entry.Key);  // key is in lowercase.
+            Assert.Throws(typeof(InvalidOperationException), () => { var v = entry.Value; });
+            CollectionAssert.AreEqual(bytes, entry.ValueBytes);
+
+            Assert.Throws(typeof(ArgumentException), () => new Metadata.Entry("abc", bytes));
+
+            Assert.AreEqual("[Entry: key=abc-bin, valueBytes=System.Byte[]]", entry.ToString());
+        }
+
+        [Test]
+        public void Entry_ConstructionPreconditions()
+        {
+            Assert.Throws(typeof(ArgumentNullException), () => new Metadata.Entry(null, "xyz"));
+            Assert.Throws(typeof(ArgumentNullException), () => new Metadata.Entry("abc", (string)null));
+            Assert.Throws(typeof(ArgumentNullException), () => new Metadata.Entry("abc-bin", (byte[])null));
+        }
+
+        [Test]
+        public void Entry_Immutable()
+        {
+            var origBytes = new byte[] { 1, 2, 3 };
+            var bytes = new byte[] { 1, 2, 3 };
+            var entry = new Metadata.Entry("ABC-BIN", bytes);
+            bytes[0] = 255;  // changing the array passed to constructor should have any effect.
+            CollectionAssert.AreEqual(origBytes, entry.ValueBytes);
+
+            entry.ValueBytes[0] = 255;
+            CollectionAssert.AreEqual(origBytes, entry.ValueBytes);
+        }
+
+        [Test]
+        public void Entry_CreateUnsafe_Ascii()
+        {
+            var bytes = new byte[] { (byte)'X', (byte)'y' };
+            var entry = Metadata.Entry.CreateUnsafe("abc", bytes);
+            Assert.IsFalse(entry.IsBinary);
+            Assert.AreEqual("abc", entry.Key);
+            Assert.AreEqual("Xy", entry.Value);
+            CollectionAssert.AreEqual(bytes, entry.ValueBytes);
+        }
+
+        [Test]
+        public void Entry_CreateUnsafe_Binary()
+        {
+            var bytes = new byte[] { 1, 2, 3 };
+            var entry = Metadata.Entry.CreateUnsafe("abc-bin", bytes);
+            Assert.IsTrue(entry.IsBinary);
+            Assert.AreEqual("abc-bin", entry.Key);
+            Assert.Throws(typeof(InvalidOperationException), () => { var v = entry.Value; });
+            CollectionAssert.AreEqual(bytes, entry.ValueBytes);
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core.Tests/ResponseHeadersTest.cs b/src/csharp/Grpc.Core.Tests/ResponseHeadersTest.cs
index 981b8ea3c8..a1648f3671 100644
--- a/src/csharp/Grpc.Core.Tests/ResponseHeadersTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ResponseHeadersTest.cs
@@ -32,13 +32,16 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+
 using Grpc.Core;
 using Grpc.Core.Internal;
 using Grpc.Core.Utils;
+
 using NUnit.Framework;
 
 namespace Grpc.Core.Tests
@@ -69,14 +72,82 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
+        [Test]
+        public async Task ResponseHeadersAsync_UnaryCall()
+        {
+            helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                return "PASS";
+            });
+
+            var call = Calls.AsyncUnaryCall(helper.CreateUnaryCall(), "");
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual(headers.Count, responseHeaders.Count);
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            Assert.AreEqual("abcdefg", responseHeaders[0].Value);
+
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_ClientStreamingCall()
+        {
+            helper.ClientStreamingHandler = new ClientStreamingServerMethod<string, string>(async (requestStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                return "PASS";
+            });
+
+            var call = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall());
+            await call.RequestStream.CompleteAsync();
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_ServerStreamingCall()
+        {
+            helper.ServerStreamingHandler = new ServerStreamingServerMethod<string, string>(async (request, responseStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                await responseStream.WriteAsync("PASS");
+            });
+
+            var call = Calls.AsyncServerStreamingCall(helper.CreateServerStreamingCall(), "");
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            CollectionAssert.AreEqual(new[] { "PASS" }, await call.ResponseStream.ToListAsync());
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_DuplexStreamingCall()
         {
-            GrpcEnvironment.Shutdown();
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                while (await requestStream.MoveNext())
+                {
+                    await responseStream.WriteAsync(requestStream.Current);
+                }
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall());
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            var messages = new[] { "PASS" };
+            await call.RequestStream.WriteAllAsync(messages);
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            CollectionAssert.AreEqual(messages, await call.ResponseStream.ToListAsync());
         }
 
         [Test]
diff --git a/src/csharp/Grpc.Core.Tests/ServerTest.cs b/src/csharp/Grpc.Core.Tests/ServerTest.cs
index 485006ebac..e7193c843b 100644
--- a/src/csharp/Grpc.Core.Tests/ServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ServerTest.cs
@@ -51,7 +51,6 @@ namespace Grpc.Core.Tests
             };
             server.Start();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -67,8 +66,7 @@ namespace Grpc.Core.Tests
             Assert.Greater(boundPort.BoundPort, 0);
 
             server.Start();
-            server.ShutdownAsync();
-            GrpcEnvironment.Shutdown();
+            server.ShutdownAsync().Wait();
         }
 
         [Test]
@@ -83,7 +81,6 @@ namespace Grpc.Core.Tests
             Assert.Throws(typeof(InvalidOperationException), () => server.Services.Add(ServerServiceDefinition.CreateBuilder("serviceName").Build()));
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
     }
 }
diff --git a/src/csharp/Grpc.Core.Tests/ShutdownTest.cs b/src/csharp/Grpc.Core.Tests/ShutdownTest.cs
new file mode 100644
index 0000000000..a2be7ddd5e
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/ShutdownTest.cs
@@ -0,0 +1,77 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class ShutdownTest
+    {
+        const string Host = "127.0.0.1";
+
+        MockServiceHelper helper;
+        Server server;
+        Channel channel;
+
+        [SetUp]
+        public void Init()
+        {
+            helper = new MockServiceHelper(Host);
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+        }
+
+        [Test]
+        public async Task AbandonedCall()
+        {
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                await requestStream.ToListAsync();
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall(new CallOptions(deadline: DateTime.UtcNow.AddMilliseconds(1))));
+
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core.Tests/TimeoutsTest.cs b/src/csharp/Grpc.Core.Tests/TimeoutsTest.cs
index d875d601b9..41f661f62d 100644
--- a/src/csharp/Grpc.Core.Tests/TimeoutsTest.cs
+++ b/src/csharp/Grpc.Core.Tests/TimeoutsTest.cs
@@ -65,16 +65,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void InfiniteDeadline()
         {
diff --git a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
index bf020cd627..5646fed3d9 100644
--- a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
@@ -40,18 +40,22 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for client streaming calls.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for this call.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this call.</typeparam>
     public sealed class AsyncClientStreamingCall<TRequest, TResponse> : IDisposable
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly Task<TResponse> responseAsync;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        internal AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseAsync = responseAsync;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -69,6 +73,17 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
+        /// <summary>
         /// Async stream to send streaming requests.
         /// </summary>
         public IClientStreamWriter<TRequest> RequestStream
@@ -89,6 +104,24 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
+        /// <summary>
         /// Provides means to cleanup after the call.
         /// If the call has already finished normally (request stream has been completed and call result has been received), doesn't do anything.
         /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
diff --git a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
index 0979de606f..e75108c7e5 100644
--- a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
@@ -32,7 +32,6 @@
 #endregion
 
 using System;
-using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
 namespace Grpc.Core
@@ -40,18 +39,22 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for bidirectional streaming calls.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for this call.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this call.</typeparam>
     public sealed class AsyncDuplexStreamingCall<TRequest, TResponse> : IDisposable
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        internal AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseStream = responseStream;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -80,6 +83,17 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
+        /// <summary>
         /// Gets the call status if the call has already finished.
         /// Throws InvalidOperationException otherwise.
         /// </summary>
diff --git a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
index 380efcdb0e..f953091984 100644
--- a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
@@ -32,7 +32,6 @@
 #endregion
 
 using System;
-using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
 namespace Grpc.Core
@@ -40,16 +39,19 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for server streaming calls.
     /// </summary>
+    /// <typeparam name="TResponse">Response message type for this call.</typeparam>
     public sealed class AsyncServerStreamingCall<TResponse> : IDisposable
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        internal AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseStream = responseStream;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -67,6 +69,17 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
+        /// <summary>
         /// Gets the call status if the call has already finished.
         /// Throws InvalidOperationException otherwise.
         /// </summary>
diff --git a/src/csharp/Grpc.Core/AsyncUnaryCall.cs b/src/csharp/Grpc.Core/AsyncUnaryCall.cs
index 224e343916..97df8f5e91 100644
--- a/src/csharp/Grpc.Core/AsyncUnaryCall.cs
+++ b/src/csharp/Grpc.Core/AsyncUnaryCall.cs
@@ -40,16 +40,19 @@ namespace Grpc.Core
     /// <summary>
     /// Return type for single request - single response call.
     /// </summary>
+    /// <typeparam name="TResponse">Response message type for this call.</typeparam>
     public sealed class AsyncUnaryCall<TResponse> : IDisposable
     {
         readonly Task<TResponse> responseAsync;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncUnaryCall(Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        internal AsyncUnaryCall(Task<TResponse> responseAsync, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseAsync = responseAsync;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -67,6 +70,17 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
+        /// <summary>
         /// Allows awaiting this object directly.
         /// </summary>
         public TaskAwaiter<TResponse> GetAwaiter()
diff --git a/src/csharp/Grpc.Core/CallInvocationDetails.cs b/src/csharp/Grpc.Core/CallInvocationDetails.cs
index 6565073fc5..8228b8f317 100644
--- a/src/csharp/Grpc.Core/CallInvocationDetails.cs
+++ b/src/csharp/Grpc.Core/CallInvocationDetails.cs
@@ -40,6 +40,8 @@ namespace Grpc.Core
     /// <summary>
     /// Details about a client-side call to be invoked.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for the call.</typeparam>
+    /// <typeparam name="TResponse">Response message type for the call.</typeparam>
     public struct CallInvocationDetails<TRequest, TResponse>
     {
         readonly Channel channel;
@@ -50,7 +52,7 @@ namespace Grpc.Core
         CallOptions options;
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="Grpc.Core.CallInvocationDetails`2"/> struct.
+        /// Initializes a new instance of the <see cref="Grpc.Core.CallInvocationDetails{TRequest,TResponse}"/> struct.
         /// </summary>
         /// <param name="channel">Channel to use for this call.</param>
         /// <param name="method">Method to call.</param>
@@ -61,7 +63,7 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="Grpc.Core.CallInvocationDetails`2"/> struct.
+        /// Initializes a new instance of the <see cref="Grpc.Core.CallInvocationDetails{TRequest,TResponse}"/> struct.
         /// </summary>
         /// <param name="channel">Channel to use for this call.</param>
         /// <param name="method">Method to call.</param>
@@ -73,7 +75,7 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="Grpc.Core.CallInvocationDetails`2"/> struct.
+        /// Initializes a new instance of the <see cref="Grpc.Core.CallInvocationDetails{TRequest,TResponse}"/> struct.
         /// </summary>
         /// <param name="channel">Channel to use for this call.</param>
         /// <param name="method">Qualified method name.</param>
@@ -158,7 +160,7 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Returns new instance of <see cref="CallInvocationDetails"/> with
+        /// Returns new instance of <see cref="CallInvocationDetails{TRequest, TResponse}"/> with
         /// <c>Options</c> set to the value provided. Values of all other fields are preserved.
         /// </summary>
         public CallInvocationDetails<TRequest, TResponse> WithOptions(CallOptions options)
diff --git a/src/csharp/Grpc.Core/CallOptions.cs b/src/csharp/Grpc.Core/CallOptions.cs
index 3dfe80b48c..c3bc9c3156 100644
--- a/src/csharp/Grpc.Core/CallOptions.cs
+++ b/src/csharp/Grpc.Core/CallOptions.cs
@@ -118,6 +118,7 @@ namespace Grpc.Core
         /// Returns new instance of <see cref="CallOptions"/> with
         /// <c>Headers</c> set to the value provided. Values of all other fields are preserved.
         /// </summary>
+        /// <param name="headers">The headers.</param>
         public CallOptions WithHeaders(Metadata headers)
         {
             var newOptions = this;
@@ -129,6 +130,7 @@ namespace Grpc.Core
         /// Returns new instance of <see cref="CallOptions"/> with
         /// <c>Deadline</c> set to the value provided. Values of all other fields are preserved.
         /// </summary>
+        /// <param name="deadline">The deadline.</param>
         public CallOptions WithDeadline(DateTime deadline)
         {
             var newOptions = this;
@@ -140,6 +142,7 @@ namespace Grpc.Core
         /// Returns new instance of <see cref="CallOptions"/> with
         /// <c>CancellationToken</c> set to the value provided. Values of all other fields are preserved.
         /// </summary>
+        /// <param name="cancellationToken">The cancellation token.</param>
         public CallOptions WithCancellationToken(CancellationToken cancellationToken)
         {
             var newOptions = this;
diff --git a/src/csharp/Grpc.Core/Calls.cs b/src/csharp/Grpc.Core/Calls.cs
index 7067456638..94b3c2fe65 100644
--- a/src/csharp/Grpc.Core/Calls.cs
+++ b/src/csharp/Grpc.Core/Calls.cs
@@ -74,7 +74,7 @@ namespace Grpc.Core
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             var asyncResult = asyncCall.UnaryCallAsync(req);
-            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -93,13 +93,14 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             asyncCall.StartServerStreamingCall(req);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
         /// Invokes a client streaming call asynchronously.
         /// In client streaming scenario, client sends a stream of requests and server responds with a single response.
         /// </summary>
+        /// <param name="call">The call defintion.</param>
         /// <returns>An awaitable call object providing access to the response.</returns>
         /// <typeparam name="TRequest">Type of request messages.</typeparam>
         /// <typeparam name="TResponse">The of response message.</typeparam>
@@ -110,7 +111,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             var resultTask = asyncCall.ClientStreamingCallAsync();
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
-            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -130,7 +131,7 @@ namespace Grpc.Core
             asyncCall.StartDuplexStreamingCall();
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/Channel.cs b/src/csharp/Grpc.Core/Channel.cs
index 64c6adf2bf..f1942727cd 100644
--- a/src/csharp/Grpc.Core/Channel.cs
+++ b/src/csharp/Grpc.Core/Channel.cs
@@ -43,17 +43,23 @@ using Grpc.Core.Utils;
 namespace Grpc.Core
 {
     /// <summary>
-    /// gRPC Channel
+    /// Represents a gRPC channel. Channels are an abstraction of long-lived connections to remote servers.
+    /// More client objects can reuse the same channel. Creating a channel is an expensive operation compared to invoking
+    /// a remote call so in general you should reuse a single channel for as many calls as possible.
     /// </summary>
-    public class Channel : IDisposable
+    public class Channel
     {
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Channel>();
 
+        readonly object myLock = new object();
+        readonly AtomicCounter activeCallCounter = new AtomicCounter();
+
         readonly string target;
         readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
         readonly List<ChannelOption> options;
-        bool disposed;
+
+        bool shutdownRequested;
 
         /// <summary>
         /// Creates a channel that connects to a specific host.
@@ -65,7 +71,7 @@ namespace Grpc.Core
         public Channel(string target, Credentials credentials, IEnumerable<ChannelOption> options = null)
         {
             this.target = Preconditions.CheckNotNull(target, "target");
-            this.environment = GrpcEnvironment.GetInstance();
+            this.environment = GrpcEnvironment.AddRef();
             this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
 
             EnsureUserAgentChannelOption(this.options);
@@ -157,6 +163,7 @@ namespace Grpc.Core
         /// There is no need to call this explicitly unless your use case requires that.
         /// Starting an RPC on a new channel will request connection implicitly.
         /// </summary>
+        /// <param name="deadline">The deadline. <c>null</c> indicates no deadline.</param>
         public async Task ConnectAsync(DateTime? deadline = null)
         {
             var currentState = handle.CheckConnectivityState(true);
@@ -172,12 +179,26 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Destroys the underlying channel.
+        /// Waits until there are no more active calls for this channel and then cleans up
+        /// resources used by this channel.
         /// </summary>
-        public void Dispose()
+        public async Task ShutdownAsync()
         {
-            Dispose(true);
-            GC.SuppressFinalize(this);
+            lock (myLock)
+            {
+                Preconditions.CheckState(!shutdownRequested);
+                shutdownRequested = true;
+            }
+
+            var activeCallCount = activeCallCounter.Count;
+            if (activeCallCount > 0)
+            {
+                Logger.Warning("Channel shutdown was called but there are still {0} active calls for that channel.", activeCallCount);
+            }
+
+            handle.Dispose();
+
+            await Task.Run(() => GrpcEnvironment.Release());
         }
 
         internal ChannelSafeHandle Handle
@@ -196,13 +217,20 @@ namespace Grpc.Core
             }
         }
 
-        protected virtual void Dispose(bool disposing)
+        internal void AddCallReference(object call)
         {
-            if (disposing && handle != null && !disposed)
-            {
-                disposed = true;
-                handle.Dispose();
-            }
+            activeCallCounter.Increment();
+
+            bool success = false;
+            handle.DangerousAddRef(ref success);
+            Preconditions.CheckState(success);
+        }
+
+        internal void RemoveCallReference(object call)
+        {
+            handle.DangerousRelease();
+
+            activeCallCounter.Decrement();
         }
 
         private static void EnsureUserAgentChannelOption(List<ChannelOption> options)
diff --git a/src/csharp/Grpc.Core/ChannelOptions.cs b/src/csharp/Grpc.Core/ChannelOptions.cs
index 0cb2953f2c..f5ef63af54 100644
--- a/src/csharp/Grpc.Core/ChannelOptions.cs
+++ b/src/csharp/Grpc.Core/ChannelOptions.cs
@@ -44,9 +44,19 @@ namespace Grpc.Core
     /// </summary>
     public sealed class ChannelOption
     {
+        /// <summary>
+        /// Type of <c>ChannelOption</c>.
+        /// </summary>
         public enum OptionType
         {
+            /// <summary>
+            /// Channel option with integer value.
+            /// </summary>
             Integer,
+            
+            /// <summary>
+            /// Channel option with string value.
+            /// </summary>
             String
         }
 
@@ -71,7 +81,7 @@ namespace Grpc.Core
         /// Creates a channel option with an integer value.
         /// </summary>
         /// <param name="name">Name.</param>
-        /// <param name="stringValue">String value.</param>
+        /// <param name="intValue">Integer value.</param>
         public ChannelOption(string name, int intValue)
         {
             this.type = OptionType.Integer;
@@ -79,6 +89,9 @@ namespace Grpc.Core
             this.intValue = intValue;
         }
 
+        /// <summary>
+        /// Gets the type of the <c>ChannelOption</c>.
+        /// </summary>
         public OptionType Type
         {
             get
@@ -87,6 +100,9 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Gets the name of the <c>ChannelOption</c>.
+        /// </summary>
         public string Name
         {
             get
@@ -95,6 +111,9 @@ namespace Grpc.Core
             }    
         }
 
+        /// <summary>
+        /// Gets the integer value the <c>ChannelOption</c>.
+        /// </summary>
         public int IntValue
         {
             get
@@ -104,6 +123,9 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Gets the string value the <c>ChannelOption</c>.
+        /// </summary>
         public string StringValue
         {
             get
@@ -140,7 +162,7 @@ namespace Grpc.Core
         /// <summary>Primary user agent: goes at the start of the user-agent metadata</summary>
         public const string PrimaryUserAgentString = "grpc.primary_user_agent";
 
-        /// <summary> Secondary user agent: goes at the end of the user-agent metadata</summary>
+        /// <summary>Secondary user agent: goes at the end of the user-agent metadata</summary>
         public const string SecondaryUserAgentString = "grpc.secondary_user_agent";
 
         /// <summary>
diff --git a/src/csharp/Grpc.Core/ClientBase.cs b/src/csharp/Grpc.Core/ClientBase.cs
index f240d777b9..f4533e735c 100644
--- a/src/csharp/Grpc.Core/ClientBase.cs
+++ b/src/csharp/Grpc.Core/ClientBase.cs
@@ -32,15 +32,15 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.Text.RegularExpressions;
-
-using Grpc.Core.Internal;
-using Grpc.Core.Utils;
+using System.Threading.Tasks;
 
 namespace Grpc.Core
 {
-    public delegate void MetadataInterceptorDelegate(string authUri, Metadata metadata);
+    /// <summary>
+    /// Interceptor for call headers.
+    /// </summary>
+    public delegate void HeaderInterceptor(IMethod method, string authUri, Metadata metadata);
 
     /// <summary>
     /// Base class for client-side stubs.
@@ -53,6 +53,10 @@ namespace Grpc.Core
         readonly Channel channel;
         readonly string authUriBase;
 
+        /// <summary>
+        /// Initializes a new instance of <c>ClientBase</c> class.
+        /// </summary>
+        /// <param name="channel">The channel to use for remote call invocation.</param>
         public ClientBase(Channel channel)
         {
             this.channel = channel;
@@ -60,10 +64,10 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Can be used to register a custom header (initial metadata) interceptor.
-        /// The delegate each time before a new call on this client is started.
+        /// Can be used to register a custom header (request metadata) interceptor.
+        /// The interceptor is invoked each time a new call on this client is started.
         /// </summary>
-        public MetadataInterceptorDelegate HeaderInterceptor
+        public HeaderInterceptor HeaderInterceptor
         {
             get;
             set;
@@ -95,6 +99,11 @@ namespace Grpc.Core
         /// <summary>
         /// Creates a new call to given method.
         /// </summary>
+        /// <param name="method">The method to invoke.</param>
+        /// <param name="options">The call options.</param>
+        /// <typeparam name="TRequest">Request message type.</typeparam>
+        /// <typeparam name="TResponse">Response message type.</typeparam>
+        /// <returns>The call invocation details.</returns>
         protected CallInvocationDetails<TRequest, TResponse> CreateCall<TRequest, TResponse>(Method<TRequest, TResponse> method, CallOptions options)
             where TRequest : class
             where TResponse : class
@@ -107,7 +116,7 @@ namespace Grpc.Core
                     options = options.WithHeaders(new Metadata());
                 }
                 var authUri = authUriBase != null ? authUriBase + method.ServiceName : null;
-                interceptor(authUri, options.Headers);
+                interceptor(method, authUri, options.Headers);
             }
             return new CallInvocationDetails<TRequest, TResponse>(channel, method, Host, options);
         }
@@ -119,7 +128,8 @@ namespace Grpc.Core
         internal static string GetAuthUriBase(string target)
         {
             var match = ChannelTargetPattern.Match(target);
-            if (!match.Success) {
+            if (!match.Success)
+            {
                 return null;
             }
             return "https://" + match.Groups[2].Value + "/";
diff --git a/src/csharp/Grpc.Core/ContextPropagationToken.cs b/src/csharp/Grpc.Core/ContextPropagationToken.cs
index 2e4bfc9e47..1d899b97fd 100644
--- a/src/csharp/Grpc.Core/ContextPropagationToken.cs
+++ b/src/csharp/Grpc.Core/ContextPropagationToken.cs
@@ -44,8 +44,8 @@ namespace Grpc.Core
     /// In situations when a backend is making calls to another backend,
     /// it makes sense to propagate properties like deadline and cancellation 
     /// token of the server call to the child call.
-    /// C core provides some other contexts (like tracing context) that
-    /// are not accessible to C# layer, but this token still allows propagating them.
+    /// The gRPC native layer provides some other contexts (like tracing context) that
+    /// are not accessible to explicitly C# layer, but this token still allows propagating them.
     /// </summary>
     public class ContextPropagationToken
     {
@@ -132,7 +132,6 @@ namespace Grpc.Core
         bool propagateDeadline;
         bool propagateCancellation;
 
-
         /// <summary>
         /// Creates new context propagation options.
         /// </summary>
@@ -144,13 +143,13 @@ namespace Grpc.Core
             this.propagateCancellation = propagateCancellation;
         }
             
-        /// <value><c>true</c> if parent call's deadline should be propagated to the child call.</value>
+        /// <summary><c>true</c> if parent call's deadline should be propagated to the child call.</summary>
         public bool IsPropagateDeadline
         {
             get { return this.propagateDeadline; }
         }
 
-        /// <value><c>true</c> if parent call's cancellation token should be propagated to the child call.</value>
+        /// <summary><c>true</c> if parent call's cancellation token should be propagated to the child call.</summary>
         public bool IsPropagateCancellation
         {
             get { return this.propagateCancellation; }
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index 055aff1444..ad2af17bc7 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -49,6 +49,7 @@
     <Compile Include="AsyncDuplexStreamingCall.cs" />
     <Compile Include="AsyncServerStreamingCall.cs" />
     <Compile Include="IClientStreamWriter.cs" />
+    <Compile Include="Internal\INativeCall.cs" />
     <Compile Include="IServerStreamWriter.cs" />
     <Compile Include="IAsyncStreamWriter.cs" />
     <Compile Include="IAsyncStreamReader.cs" />
diff --git a/src/csharp/Grpc.Core/GrpcEnvironment.cs b/src/csharp/Grpc.Core/GrpcEnvironment.cs
index 30d8c80235..e7c04185c2 100644
--- a/src/csharp/Grpc.Core/GrpcEnvironment.cs
+++ b/src/csharp/Grpc.Core/GrpcEnvironment.cs
@@ -58,6 +58,7 @@ namespace Grpc.Core
 
         static object staticLock = new object();
         static GrpcEnvironment instance;
+        static int refCount;
 
         static ILogger logger = new ConsoleLogger();
 
@@ -67,13 +68,14 @@ namespace Grpc.Core
         bool isClosed;
 
         /// <summary>
-        /// Returns an instance of initialized gRPC environment.
-        /// Subsequent invocations return the same instance unless Shutdown has been called first.
+        /// Returns a reference-counted instance of initialized gRPC environment.
+        /// Subsequent invocations return the same instance unless reference count has dropped to zero previously.
         /// </summary>
-        internal static GrpcEnvironment GetInstance()
+        internal static GrpcEnvironment AddRef()
         {
             lock (staticLock)
             {
+                refCount++;
                 if (instance == null)
                 {
                     instance = new GrpcEnvironment();
@@ -83,14 +85,16 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Shuts down the gRPC environment if it was initialized before.
-        /// Blocks until the environment has been fully shutdown.
+        /// Decrements the reference count for currently active environment and shuts down the gRPC environment if reference count drops to zero.
+        /// (and blocks until the environment has been fully shutdown).
         /// </summary>
-        public static void Shutdown()
+        internal static void Release()
         {
             lock (staticLock)
             {
-                if (instance != null)
+                Preconditions.CheckState(refCount > 0);
+                refCount--;
+                if (refCount == 0)
                 {
                     instance.Close();
                     instance = null;
@@ -98,6 +102,14 @@ namespace Grpc.Core
             }
         }
 
+        internal static int GetRefCount()
+        {
+            lock (staticLock)
+            {
+                return refCount;
+            }
+        }
+
         /// <summary>
         /// Gets application-wide logger used by gRPC.
         /// </summary>
@@ -125,12 +137,10 @@ namespace Grpc.Core
         private GrpcEnvironment()
         {
             NativeLogRedirector.Redirect();
-            grpcsharp_init();
+            GrpcNativeInit();
             completionRegistry = new CompletionRegistry(this);
             threadPool = new GrpcThreadPool(this, THREAD_POOL_SIZE);
             threadPool.Start();
-            // TODO: use proper logging here
-            Logger.Info("gRPC initialized.");
         }
 
         /// <summary>
@@ -175,6 +185,16 @@ namespace Grpc.Core
             return Marshal.PtrToStringAnsi(ptr);
         }
 
+        internal static void GrpcNativeInit()
+        {
+            grpcsharp_init();
+        }
+
+        internal static void GrpcNativeShutdown()
+        {
+            grpcsharp_shutdown();
+        }
+
         /// <summary>
         /// Shuts down this environment.
         /// </summary>
@@ -185,12 +205,10 @@ namespace Grpc.Core
                 throw new InvalidOperationException("Close has already been called");
             }
             threadPool.Stop();
-            grpcsharp_shutdown();
+            GrpcNativeShutdown();
             isClosed = true;
 
             debugStats.CheckOK();
-
-            Logger.Info("gRPC shutdown.");
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/IAsyncStreamReader.cs b/src/csharp/Grpc.Core/IAsyncStreamReader.cs
index c0a0674e50..49e1ea7832 100644
--- a/src/csharp/Grpc.Core/IAsyncStreamReader.cs
+++ b/src/csharp/Grpc.Core/IAsyncStreamReader.cs
@@ -42,7 +42,7 @@ namespace Grpc.Core
     /// <summary>
     /// A stream of messages to be read.
     /// </summary>
-    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="T">The message type.</typeparam>
     public interface IAsyncStreamReader<T> : IAsyncEnumerator<T>
     {
         // TODO(jtattermusch): consider just using IAsyncEnumerator instead of this interface.
diff --git a/src/csharp/Grpc.Core/IAsyncStreamWriter.cs b/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
index 4e2acb9c71..9c0d2d312e 100644
--- a/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IAsyncStreamWriter.cs
@@ -42,7 +42,7 @@ namespace Grpc.Core
     /// <summary>
     /// A writable stream of messages.
     /// </summary>
-    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="T">The message type.</typeparam>
     public interface IAsyncStreamWriter<T>
     {
         /// <summary>
@@ -56,7 +56,7 @@ namespace Grpc.Core
         /// If null, default options will be used.
         /// Once set, this property maintains its value across subsequent
         /// writes.
-        /// <value>The write options.</value>
+        /// </summary>
         WriteOptions WriteOptions { get; set; }
     }
 }
diff --git a/src/csharp/Grpc.Core/IClientStreamWriter.cs b/src/csharp/Grpc.Core/IClientStreamWriter.cs
index a3028bc374..3fd0774db5 100644
--- a/src/csharp/Grpc.Core/IClientStreamWriter.cs
+++ b/src/csharp/Grpc.Core/IClientStreamWriter.cs
@@ -42,7 +42,7 @@ namespace Grpc.Core
     /// <summary>
     /// Client-side writable stream of messages with Close capability.
     /// </summary>
-    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="T">The message type.</typeparam>
     public interface IClientStreamWriter<T> : IAsyncStreamWriter<T>
     {
         /// <summary>
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCall.cs b/src/csharp/Grpc.Core/Internal/AsyncCall.cs
index 2c3e3d75ea..be5d611a53 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCall.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCall.cs
@@ -51,22 +51,35 @@ namespace Grpc.Core.Internal
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<AsyncCall<TRequest, TResponse>>();
 
         readonly CallInvocationDetails<TRequest, TResponse> details;
+        readonly INativeCall injectedNativeCall;  // for testing
 
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
+        // Indicates that steaming call has finished.
+        TaskCompletionSource<object> streamingCallFinishedTcs = new TaskCompletionSource<object>();
+
+        // Response headers set here once received.
+        TaskCompletionSource<Metadata> responseHeadersTcs = new TaskCompletionSource<Metadata>();
+
         // Set after status is received. Used for both unary and streaming response calls.
         ClientSideStatus? finishedStatus;
 
-        bool readObserverCompleted;  // True if readObserver has already been completed.
-
         public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails)
-            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer)
+            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer, callDetails.Channel.Environment)
         {
             this.details = callDetails.WithOptions(callDetails.Options.Normalize());
             this.initialMetadataSent = true;  // we always send metadata at the very beginning of the call.
         }
 
+        /// <summary>
+        /// This constructor should only be used for testing.
+        /// </summary>
+        public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails, INativeCall injectedNativeCall) : this(callDetails)
+        {
+            this.injectedNativeCall = injectedNativeCall;
+        }
+
         // TODO: this method is not Async, so it shouldn't be in AsyncCall class, but 
         // it is reusing fair amount of code in this class, so we are leaving it here.
         /// <summary>
@@ -100,7 +113,7 @@ namespace Grpc.Core.Internal
                         bool success = (ev.success != 0);
                         try
                         {
-                            HandleUnaryResponse(success, ctx);
+                            HandleUnaryResponse(success, ctx.GetReceivedStatusOnClient(), ctx.GetReceivedMessage(), ctx.GetReceivedInitialMetadata());
                         }
                         catch (Exception e)
                         {
@@ -125,7 +138,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 halfcloseRequested = true;
                 readingDone = true;
@@ -152,7 +165,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 readingDone = true;
 
@@ -176,10 +189,9 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 halfcloseRequested = true;
-                halfclosed = true;  // halfclose not confirmed yet, but it will be once finishedHandler is called.
 
                 byte[] payload = UnsafeSerialize(msg);
 
@@ -187,6 +199,7 @@ namespace Grpc.Core.Internal
                 {
                     call.StartServerStreaming(HandleFinished, payload, metadataArray, GetWriteFlagsForCall());
                 }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
         }
 
@@ -201,12 +214,13 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
                     call.StartDuplexStreaming(HandleFinished, metadataArray);
                 }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
         }
 
@@ -248,6 +262,28 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
+        /// Get the task that completes once if streaming call finishes with ok status and throws RpcException with given status otherwise.
+        /// </summary>
+        public Task StreamingCallFinishedTask
+        {
+            get
+            {
+                return streamingCallFinishedTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Get the task that completes once response headers are received.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return responseHeadersTcs.Task;
+            }
+        }
+
+        /// <summary>
         /// Gets the resulting status if the call has already finished.
         /// Throws InvalidOperationException otherwise.
         /// </summary>
@@ -281,51 +317,31 @@ namespace Grpc.Core.Internal
             }
         }
 
-        /// <summary>
-        /// On client-side, we only fire readCompletionDelegate once all messages have been read 
-        /// and status has been received.
-        /// </summary>
-        protected override void ProcessLastRead(AsyncCompletionDelegate<TResponse> completionDelegate)
+        protected override void OnAfterReleaseResources()
         {
-            if (completionDelegate != null && readingDone && finishedStatus.HasValue)
-            {
-                bool shouldComplete;
-                lock (myLock)
-                {
-                    shouldComplete = !readObserverCompleted;
-                    readObserverCompleted = true;
-                }
-
-                if (shouldComplete)
-                {
-                    var status = finishedStatus.Value.Status;
-                    if (status.StatusCode != StatusCode.OK)
-                    {
-                        FireCompletion(completionDelegate, default(TResponse), new RpcException(status));
-                    }
-                    else
-                    {
-                        FireCompletion(completionDelegate, default(TResponse), null);
-                    }
-                }
-            }
+            details.Channel.RemoveCallReference(this);
         }
 
-        protected override void OnReleaseResources()
+        private void Initialize(CompletionQueueSafeHandle cq)
         {
-            details.Channel.Environment.DebugStats.ActiveClientCalls.Decrement();
+            var call = CreateNativeCall(cq);
+            details.Channel.AddCallReference(this);
+            InitializeInternal(call);
+            RegisterCancellationCallback();
         }
 
-        private void Initialize(CompletionQueueSafeHandle cq)
+        private INativeCall CreateNativeCall(CompletionQueueSafeHandle cq)
         {
+            if (injectedNativeCall != null)
+            {
+                return injectedNativeCall;  // allows injecting a mock INativeCall in tests.
+            }
+
             var parentCall = details.Options.PropagationToken != null ? details.Options.PropagationToken.ParentCall : CallSafeHandle.NullInstance;
 
-            var call = details.Channel.Handle.CreateCall(details.Channel.Environment.CompletionRegistry,
+            return details.Channel.Handle.CreateCall(environment.CompletionRegistry,
                 parentCall, ContextPropagationToken.DefaultMask, cq,
                 details.Method, details.Host, Timespec.FromDateTime(details.Options.Deadline.Value));
-            details.Channel.Environment.DebugStats.ActiveClientCalls.Increment();
-            InitializeInternal(call);
-            RegisterCancellationCallback();
         }
 
         // Make sure that once cancellationToken for this call is cancelled, Cancel() will be called.
@@ -348,31 +364,31 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
-        /// Handler for unary response completion.
+        /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleUnaryResponse(bool success, BatchContextSafeHandle ctx)
+        private void HandleReceivedResponseHeaders(bool success, Metadata responseHeaders)
         {
-            var fullStatus = ctx.GetReceivedStatusOnClient();
+            responseHeadersTcs.SetResult(responseHeaders);
+        }
 
+        /// <summary>
+        /// Handler for unary response completion.
+        /// </summary>
+        private void HandleUnaryResponse(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders)
+        {
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = fullStatus;
-
-                halfclosed = true;
+                finishedStatus = receivedStatus;
 
                 ReleaseResourcesIfPossible();
             }
 
-            if (!success)
-            {
-                unaryResponseTcs.SetException(new RpcException(new Status(StatusCode.Internal, "Internal error occured.")));
-                return;
-            }
+            responseHeadersTcs.SetResult(responseHeaders);
 
-            var status = fullStatus.Status;
+            var status = receivedStatus.Status;
 
-            if (status.StatusCode != StatusCode.OK)
+            if (!success || status.StatusCode != StatusCode.OK)
             {
                 unaryResponseTcs.SetException(new RpcException(status));
                 return;
@@ -380,7 +396,7 @@ namespace Grpc.Core.Internal
 
             // TODO: handle deserialization error
             TResponse msg;
-            TryDeserialize(ctx.GetReceivedMessage(), out msg);
+            TryDeserialize(receivedMessage, out msg);
 
             unaryResponseTcs.SetResult(msg);
         }
@@ -388,22 +404,25 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleFinished(bool success, BatchContextSafeHandle ctx)
+        private void HandleFinished(bool success, ClientSideStatus receivedStatus)
         {
-            var fullStatus = ctx.GetReceivedStatusOnClient();
-
-            AsyncCompletionDelegate<TResponse> origReadCompletionDelegate = null;
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = fullStatus;
-
-                origReadCompletionDelegate = readCompletionDelegate;
+                finishedStatus = receivedStatus;
 
                 ReleaseResourcesIfPossible();
             }
 
-            ProcessLastRead(origReadCompletionDelegate);
+            var status = receivedStatus.Status;
+
+            if (!success || status.StatusCode != StatusCode.OK)
+            {
+                streamingCallFinishedTcs.SetException(new RpcException(status));
+                return;
+            }
+
+            streamingCallFinishedTcs.SetResult(null);
         }
     }
 }
\ No newline at end of file
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs b/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs
index 6ca4bbdafc..4d20394644 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs
@@ -54,30 +54,30 @@ namespace Grpc.Core.Internal
         readonly Func<TWrite, byte[]> serializer;
         readonly Func<byte[], TRead> deserializer;
 
+        protected readonly GrpcEnvironment environment;
         protected readonly object myLock = new object();
 
-        protected CallSafeHandle call;
+        protected INativeCall call;
         protected bool disposed;
 
         protected bool started;
-        protected bool errorOccured;
         protected bool cancelRequested;
 
         protected AsyncCompletionDelegate<object> sendCompletionDelegate;  // Completion of a pending send or sendclose if not null.
         protected AsyncCompletionDelegate<TRead> readCompletionDelegate;  // Completion of a pending send or sendclose if not null.
 
-        protected bool readingDone;
-        protected bool halfcloseRequested;
-        protected bool halfclosed;
+        protected bool readingDone;  // True if last read (i.e. read with null payload) was already received.
+        protected bool halfcloseRequested;  // True if send close have been initiated.
         protected bool finished;  // True if close has been received from the peer.
 
         protected bool initialMetadataSent;
-        protected long streamingWritesCounter;
+        protected long streamingWritesCounter;  // Number of streaming send operations started so far.
 
-        public AsyncCallBase(Func<TWrite, byte[]> serializer, Func<byte[], TRead> deserializer)
+        public AsyncCallBase(Func<TWrite, byte[]> serializer, Func<byte[], TRead> deserializer, GrpcEnvironment environment)
         {
             this.serializer = Preconditions.CheckNotNull(serializer);
             this.deserializer = Preconditions.CheckNotNull(deserializer);
+            this.environment = Preconditions.CheckNotNull(environment);
         }
 
         /// <summary>
@@ -114,7 +114,7 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected void InitializeInternal(CallSafeHandle call)
+        protected void InitializeInternal(INativeCall call)
         {
             lock (myLock)
             {
@@ -159,16 +159,6 @@ namespace Grpc.Core.Internal
             }
         }
 
-        // TODO(jtattermusch): find more fitting name for this method.
-        /// <summary>
-        /// Default behavior just completes the read observer, but more sofisticated behavior might be required
-        /// by subclasses.
-        /// </summary>
-        protected virtual void ProcessLastRead(AsyncCompletionDelegate<TRead> completionDelegate)
-        {
-            FireCompletion(completionDelegate, default(TRead), null);
-        }
-
         /// <summary>
         /// If there are no more pending actions and no new actions can be started, releases
         /// the underlying native resources.
@@ -177,7 +167,7 @@ namespace Grpc.Core.Internal
         {
             if (!disposed && call != null)
             {
-                bool noMoreSendCompletions = halfclosed || (cancelRequested && sendCompletionDelegate == null);
+                bool noMoreSendCompletions = sendCompletionDelegate == null && (halfcloseRequested || cancelRequested || finished);
                 if (noMoreSendCompletions && readingDone && finished)
                 {
                     ReleaseResources();
@@ -189,34 +179,33 @@ namespace Grpc.Core.Internal
 
         private void ReleaseResources()
         {
-            OnReleaseResources();
             if (call != null)
             {
                 call.Dispose();
             }
             disposed = true;
+            OnAfterReleaseResources();
         }
 
-        protected virtual void OnReleaseResources()
+        protected virtual void OnAfterReleaseResources()
         {
         }
 
         protected void CheckSendingAllowed()
         {
             Preconditions.CheckState(started);
-            Preconditions.CheckState(!errorOccured);
             CheckNotCancelled();
             Preconditions.CheckState(!disposed);
 
             Preconditions.CheckState(!halfcloseRequested, "Already halfclosed.");
+            Preconditions.CheckState(!finished, "Already finished.");
             Preconditions.CheckState(sendCompletionDelegate == null, "Only one write can be pending at a time");
         }
 
-        protected void CheckReadingAllowed()
+        protected virtual void CheckReadingAllowed()
         {
             Preconditions.CheckState(started);
             Preconditions.CheckState(!disposed);
-            Preconditions.CheckState(!errorOccured);
 
             Preconditions.CheckState(!readingDone, "Stream has already been closed.");
             Preconditions.CheckState(readCompletionDelegate == null, "Only one read can be pending at a time");
@@ -280,7 +269,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles send completion.
         /// </summary>
-        protected void HandleSendFinished(bool success, BatchContextSafeHandle ctx)
+        protected void HandleSendFinished(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
@@ -304,12 +293,11 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles halfclose completion.
         /// </summary>
-        protected void HandleHalfclosed(bool success, BatchContextSafeHandle ctx)
+        protected void HandleHalfclosed(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
             {
-                halfclosed = true;
                 origCompletionDelegate = sendCompletionDelegate;
                 sendCompletionDelegate = null;
 
@@ -329,23 +317,17 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles streaming read completion.
         /// </summary>
-        protected void HandleReadFinished(bool success, BatchContextSafeHandle ctx)
+        protected void HandleReadFinished(bool success, byte[] receivedMessage)
         {
-            var payload = ctx.GetReceivedMessage();
-
             AsyncCompletionDelegate<TRead> origCompletionDelegate = null;
             lock (myLock)
             {
                 origCompletionDelegate = readCompletionDelegate;
-                if (payload != null)
-                {
-                    readCompletionDelegate = null;
-                }
-                else
+                readCompletionDelegate = null;
+
+                if (receivedMessage == null)
                 {
-                    // This was the last read. Keeping the readCompletionDelegate
-                    // to be either fired by this handler or by client-side finished
-                    // handler.
+                    // This was the last read.
                     readingDone = true;
                 }
 
@@ -354,17 +336,17 @@ namespace Grpc.Core.Internal
 
             // TODO: handle the case when error occured...
 
-            if (payload != null)
+            if (receivedMessage != null)
             {
                 // TODO: handle deserialization error
                 TRead msg;
-                TryDeserialize(payload, out msg);
+                TryDeserialize(receivedMessage, out msg);
 
                 FireCompletion(origCompletionDelegate, msg, null);
             }
             else
             {
-                ProcessLastRead(origCompletionDelegate);
+                FireCompletion(origCompletionDelegate, default(TRead), null);
             }
         }
     }
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
index 3710a65d6b..5c47251030 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
@@ -49,17 +49,18 @@ namespace Grpc.Core.Internal
     {
         readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
         readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
-        readonly GrpcEnvironment environment;
+        readonly Server server;
 
-        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment) : base(serializer, deserializer)
+        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment, Server server) : base(serializer, deserializer, environment)
         {
-            this.environment = Preconditions.CheckNotNull(environment);
+            this.server = Preconditions.CheckNotNull(server);
         }
 
         public void Initialize(CallSafeHandle call)
         {
             call.SetCompletionRegistry(environment.CompletionRegistry);
-            environment.DebugStats.ActiveServerCalls.Increment();
+
+            server.AddCallReference(this);
             InitializeInternal(call);
         }
 
@@ -168,18 +169,22 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected override void OnReleaseResources()
+        protected override void CheckReadingAllowed()
         {
-            environment.DebugStats.ActiveServerCalls.Decrement();
+            base.CheckReadingAllowed();
+            Preconditions.CheckArgument(!cancelRequested);
+        }
+
+        protected override void OnAfterReleaseResources()
+        {
+            server.RemoveCallReference(this);
         }
 
         /// <summary>
         /// Handles the server side close completion.
         /// </summary>
-        private void HandleFinishedServerside(bool success, BatchContextSafeHandle ctx)
+        private void HandleFinishedServerside(bool success, bool cancelled)
         {
-            bool cancelled = ctx.GetReceivedCloseOnServerCancelled();
-
             lock (myLock)
             {
                 finished = true;
diff --git a/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs b/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs
index 6a2add54db..3a96414bea 100644
--- a/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs
@@ -134,7 +134,7 @@ namespace Grpc.Core.Internal
         }
 
         // Gets data of server_rpc_new completion.
-        public ServerRpcNew GetServerRpcNew()
+        public ServerRpcNew GetServerRpcNew(Server server)
         {
             var call = grpcsharp_batch_context_server_rpc_new_call(this);
 
@@ -145,7 +145,7 @@ namespace Grpc.Core.Internal
             IntPtr metadataArrayPtr = grpcsharp_batch_context_server_rpc_new_request_metadata(this);
             var metadata = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);
 
-            return new ServerRpcNew(call, method, host, deadline, metadata);
+            return new ServerRpcNew(server, call, method, host, deadline, metadata);
         }
 
         // Gets data of receive_close_on_server completion.
@@ -198,14 +198,16 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal struct ServerRpcNew
     {
+        readonly Server server;
         readonly CallSafeHandle call;
         readonly string method;
         readonly string host;
         readonly Timespec deadline;
         readonly Metadata requestMetadata;
 
-        public ServerRpcNew(CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
+        public ServerRpcNew(Server server, CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
         {
+            this.server = server;
             this.call = call;
             this.method = method;
             this.host = host;
@@ -213,6 +215,14 @@ namespace Grpc.Core.Internal
             this.requestMetadata = requestMetadata;
         }
 
+        public Server Server
+        {
+            get
+            {
+                return this.server;
+            }
+        }
+
         public CallSafeHandle Call
         {
             get
diff --git a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
index 3cb01e29bd..c3611a7761 100644
--- a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
@@ -38,9 +38,9 @@ using Grpc.Core.Utils;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_call from <grpc/grpc.h>
+    /// grpc_call from <c>grpc/grpc.h</c>
     /// </summary>
-    internal class CallSafeHandle : SafeHandleZeroIsInvalid
+    internal class CallSafeHandle : SafeHandleZeroIsInvalid, INativeCall
     {
         public static readonly CallSafeHandle NullInstance = new CallSafeHandle();
 
@@ -87,6 +87,10 @@ namespace Grpc.Core.Internal
             BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
+        static extern GRPCCallError grpcsharp_call_recv_initial_metadata(CallSafeHandle call,
+            BatchContextSafeHandle ctx);
+
+        [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_serverside(CallSafeHandle call,
             BatchContextSafeHandle ctx);
 
@@ -109,10 +113,10 @@ namespace Grpc.Core.Internal
             this.completionRegistry = completionRegistry;
         }
 
-        public void StartUnary(BatchCompletionDelegate callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
             grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags)
                 .CheckOk();
         }
@@ -123,66 +127,73 @@ namespace Grpc.Core.Internal
                 .CheckOk();
         }
 
-        public void StartClientStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
             grpcsharp_call_start_client_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartServerStreaming(BatchCompletionDelegate callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
             grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags).CheckOk();
         }
 
-        public void StartDuplexStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
             grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartSendMessage(BatchCompletionDelegate callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
+        public void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_message(this, ctx, payload, new UIntPtr((ulong)payload.Length), writeFlags, sendEmptyInitialMetadata).CheckOk();
         }
 
-        public void StartSendCloseFromClient(BatchCompletionDelegate callback)
+        public void StartSendCloseFromClient(SendCompletionHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_close_from_client(this, ctx).CheckOk();
         }
 
-        public void StartSendStatusFromServer(BatchCompletionDelegate callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata).CheckOk();
         }
 
-        public void StartReceiveMessage(BatchCompletionDelegate callback)
+        public void StartReceiveMessage(ReceivedMessageHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedMessage()));
             grpcsharp_call_recv_message(this, ctx).CheckOk();
         }
 
-        public void StartServerSide(BatchCompletionDelegate callback)
+        public void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback)
+        {
+            var ctx = BatchContextSafeHandle.Create();
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedInitialMetadata()));
+            grpcsharp_call_recv_initial_metadata(this, ctx).CheckOk();
+        }
+
+        public void StartServerSide(ReceivedCloseOnServerHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedCloseOnServerCancelled()));
             grpcsharp_call_start_serverside(this, ctx).CheckOk();
         }
 
-        public void StartSendInitialMetadata(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_initial_metadata(this, ctx, metadataArray).CheckOk();
         }
 
diff --git a/src/csharp/Grpc.Core/Internal/ChannelArgsSafeHandle.cs b/src/csharp/Grpc.Core/Internal/ChannelArgsSafeHandle.cs
index c12aec5a3a..ea5b52374e 100644
--- a/src/csharp/Grpc.Core/Internal/ChannelArgsSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/ChannelArgsSafeHandle.cs
@@ -35,7 +35,7 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_channel_args from <grpc/grpc.h>
+    /// grpc_channel_args from <c>grpc/grpc.h</c>
     /// </summary>
     internal class ChannelArgsSafeHandle : SafeHandleZeroIsInvalid
     {
diff --git a/src/csharp/Grpc.Core/Internal/ChannelSafeHandle.cs b/src/csharp/Grpc.Core/Internal/ChannelSafeHandle.cs
index 7f03bf4ea5..7a1c6e3dac 100644
--- a/src/csharp/Grpc.Core/Internal/ChannelSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/ChannelSafeHandle.cs
@@ -36,7 +36,7 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_channel from <grpc/grpc.h>
+    /// grpc_channel from <c>grpc/grpc.h</c>
     /// </summary>
     internal class ChannelSafeHandle : SafeHandleZeroIsInvalid
     {
@@ -68,11 +68,17 @@ namespace Grpc.Core.Internal
 
         public static ChannelSafeHandle CreateInsecure(string target, ChannelArgsSafeHandle channelArgs)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_insecure_channel_create(target, channelArgs);
         }
 
         public static ChannelSafeHandle CreateSecure(CredentialsSafeHandle credentials, string target, ChannelArgsSafeHandle channelArgs)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_secure_channel_create(credentials, target, channelArgs);
         }
 
@@ -107,6 +113,7 @@ namespace Grpc.Core.Internal
         protected override bool ReleaseHandle()
         {
             grpcsharp_channel_destroy(handle);
+            GrpcEnvironment.GrpcNativeShutdown();
             return true;
         }
     }
diff --git a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
index 6c44521038..b4a7335c7c 100644
--- a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
@@ -72,7 +72,13 @@ namespace Grpc.Core.Internal
             call.StartReadMessage(taskSource.CompletionDelegate);
             var result = await taskSource.Task;
             this.current = result;
-            return result != null;
+
+            if (result == null)
+            {
+                await call.StreamingCallFinishedTask;
+                return false;
+            }
+            return true;
         }
 
         public void Dispose()
diff --git a/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs
index f64f3d4175..f7a3471bb4 100644
--- a/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs
@@ -35,7 +35,7 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_completion_queue from <grpc/grpc.h>
+    /// grpc_completion_queue from <c>grpc/grpc.h</c>
     /// </summary>
     internal class CompletionQueueSafeHandle : SafeHandleZeroIsInvalid
     {
diff --git a/src/csharp/Grpc.Core/Internal/CredentialsSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CredentialsSafeHandle.cs
index 8b4fa85e5d..feed335362 100644
--- a/src/csharp/Grpc.Core/Internal/CredentialsSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CredentialsSafeHandle.cs
@@ -36,7 +36,7 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_credentials from <grpc/grpc_security.h>
+    /// grpc_credentials from <c>grpc/grpc_security.h</c>
     /// </summary>
     internal class CredentialsSafeHandle : SafeHandleZeroIsInvalid
     {
diff --git a/src/csharp/Grpc.Core/Internal/DebugStats.cs b/src/csharp/Grpc.Core/Internal/DebugStats.cs
index 8793450ff3..1bea1adf9e 100644
--- a/src/csharp/Grpc.Core/Internal/DebugStats.cs
+++ b/src/csharp/Grpc.Core/Internal/DebugStats.cs
@@ -38,10 +38,6 @@ namespace Grpc.Core.Internal
 {
     internal class DebugStats
     {
-        public readonly AtomicCounter ActiveClientCalls = new AtomicCounter();
-
-        public readonly AtomicCounter ActiveServerCalls = new AtomicCounter();
-
         public readonly AtomicCounter PendingBatchCompletions = new AtomicCounter();
 
         /// <summary>
@@ -49,16 +45,6 @@ namespace Grpc.Core.Internal
         /// </summary>
         public void CheckOK()
         {
-            var remainingClientCalls = ActiveClientCalls.Count;
-            if (remainingClientCalls != 0)
-            {                
-                DebugWarning(string.Format("Detected {0} client calls that weren't disposed properly.", remainingClientCalls));
-            }
-            var remainingServerCalls = ActiveServerCalls.Count;
-            if (remainingServerCalls != 0)
-            {
-                DebugWarning(string.Format("Detected {0} server calls that weren't disposed properly.", remainingServerCalls));
-            }
             var pendingBatchCompletions = PendingBatchCompletions.Count;
             if (pendingBatchCompletions != 0)
             {
diff --git a/src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs b/src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs
index cb4c7c821e..4b7124ee74 100644
--- a/src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs
+++ b/src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs
@@ -83,8 +83,6 @@ namespace Grpc.Core.Internal
             lock (myLock)
             {
                 cq.Shutdown();
-
-                Logger.Info("Waiting for GRPC threads to finish.");
                 foreach (var thread in threads)
                 {
                     thread.Join();
@@ -136,7 +134,6 @@ namespace Grpc.Core.Internal
                 }
             }
             while (ev.type != GRPCCompletionType.Shutdown);
-            Logger.Info("Completion queue has shutdown successfully, thread {0} exiting.", Thread.CurrentThread.Name);
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/INativeCall.cs b/src/csharp/Grpc.Core/Internal/INativeCall.cs
new file mode 100644
index 0000000000..cbef599139
--- /dev/null
+++ b/src/csharp/Grpc.Core/Internal/INativeCall.cs
@@ -0,0 +1,85 @@
+#region Copyright notice and license
+// Copyright 2015, Google Inc.
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// 
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+
+namespace Grpc.Core.Internal
+{
+    internal delegate void UnaryResponseClientHandler(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders);
+
+    // Received status for streaming response calls.
+    internal delegate void ReceivedStatusOnClientHandler(bool success, ClientSideStatus receivedStatus);
+
+    internal delegate void ReceivedMessageHandler(bool success, byte[] receivedMessage);
+
+    internal delegate void ReceivedResponseHeadersHandler(bool success, Metadata responseHeaders);
+
+    internal delegate void SendCompletionHandler(bool success);
+
+    internal delegate void ReceivedCloseOnServerHandler(bool success, bool cancelled);
+
+    /// <summary>
+    /// Abstraction of a native call object.
+    /// </summary>
+    internal interface INativeCall : IDisposable
+    {
+        void Cancel();
+
+        void CancelWithStatus(Grpc.Core.Status status);
+
+        string GetPeer();
+
+        void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartReceiveMessage(ReceivedMessageHandler callback);
+
+        void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback);
+
+        void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartSendMessage(SendCompletionHandler callback, byte[] payload, Grpc.Core.WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+
+        void StartSendCloseFromClient(SendCompletionHandler callback);
+
+        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+
+        void StartServerSide(ReceivedCloseOnServerHandler callback);
+    }
+}
diff --git a/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs b/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs
index 427c16fac6..31b834c979 100644
--- a/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs
@@ -35,7 +35,7 @@ using System.Threading.Tasks;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_metadata_array from <grpc/grpc.h>
+    /// grpc_metadata_array from <c>grpc/grpc.h</c>
     /// </summary>
     internal class MetadataArraySafeHandle : SafeHandleZeroIsInvalid
     {
@@ -70,7 +70,8 @@ namespace Grpc.Core.Internal
             var metadataArray = grpcsharp_metadata_array_create(new UIntPtr((ulong)metadata.Count));
             for (int i = 0; i < metadata.Count; i++)
             {
-                grpcsharp_metadata_array_add(metadataArray, metadata[i].Key, metadata[i].ValueBytes, new UIntPtr((ulong)metadata[i].ValueBytes.Length));
+                var valueBytes = metadata[i].GetSerializedValueUnsafe();
+                grpcsharp_metadata_array_add(metadataArray, metadata[i].Key, valueBytes, new UIntPtr((ulong)valueBytes.Length));
             }
             return metadataArray;
         }
@@ -94,7 +95,7 @@ namespace Grpc.Core.Internal
                 string key = Marshal.PtrToStringAnsi(grpcsharp_metadata_array_get_key(metadataArray, index));
                 var bytes = new byte[grpcsharp_metadata_array_get_value_length(metadataArray, index).ToUInt64()];
                 Marshal.Copy(grpcsharp_metadata_array_get_value(metadataArray, index), bytes, 0, bytes.Length);
-                metadata.Add(new Metadata.Entry(key, bytes));
+                metadata.Add(Metadata.Entry.CreateUnsafe(key, bytes));
             }
             return metadata;
         }
diff --git a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
index 688f9f6fec..59f4c5727c 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
@@ -67,7 +67,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -123,7 +123,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -179,7 +179,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -239,7 +239,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -278,7 +278,7 @@ namespace Grpc.Core.Internal
         {
             // We don't care about the payload type here.
             var asyncCall = new AsyncCallServer<byte[], byte[]>(
-                (payload) => payload, (payload) => payload, environment);
+                (payload) => payload, (payload) => payload, environment, newRpc.Server);
             
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
diff --git a/src/csharp/Grpc.Core/Internal/ServerCredentialsSafeHandle.cs b/src/csharp/Grpc.Core/Internal/ServerCredentialsSafeHandle.cs
index 37a4f5256b..51e352a18b 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCredentialsSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCredentialsSafeHandle.cs
@@ -37,7 +37,7 @@ using Grpc.Core.Utils;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// grpc_server_credentials from <grpc/grpc_security.h>
+    /// grpc_server_credentials from <c>grpc/grpc_security.h</c>
     /// </summary>
     internal class ServerCredentialsSafeHandle : SafeHandleZeroIsInvalid
     {
diff --git a/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs b/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
index f9b44b1acf..5ee7ac14e8 100644
--- a/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
@@ -74,6 +74,9 @@ namespace Grpc.Core.Internal
 
         public static ServerSafeHandle NewServer(CompletionQueueSafeHandle cq, ChannelArgsSafeHandle args)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_server_create(cq, args);
         }
 
@@ -109,6 +112,7 @@ namespace Grpc.Core.Internal
         protected override bool ReleaseHandle()
         {
             grpcsharp_server_destroy(handle);
+            GrpcEnvironment.GrpcNativeShutdown();
             return true;
         }
             
diff --git a/src/csharp/Grpc.Core/Logging/ConsoleLogger.cs b/src/csharp/Grpc.Core/Logging/ConsoleLogger.cs
index 382481d871..35561d25d8 100644
--- a/src/csharp/Grpc.Core/Logging/ConsoleLogger.cs
+++ b/src/csharp/Grpc.Core/Logging/ConsoleLogger.cs
@@ -51,7 +51,19 @@ namespace Grpc.Core.Logging
         private ConsoleLogger(Type forType)
         {
             this.forType = forType;
-            this.forTypeString = forType != null ? forType.FullName + " " : "";
+            if (forType != null)
+            {
+                var namespaceStr = forType.Namespace ?? "";
+                if (namespaceStr.Length > 0)
+                {
+                     namespaceStr += ".";
+                }
+                this.forTypeString = namespaceStr + forType.Name + " ";
+            }
+            else
+            {
+                this.forTypeString = "";
+            }
         }
  
         /// <summary>
diff --git a/src/csharp/Grpc.Core/Metadata.cs b/src/csharp/Grpc.Core/Metadata.cs
index 9db2abf46e..99fe0b5478 100644
--- a/src/csharp/Grpc.Core/Metadata.cs
+++ b/src/csharp/Grpc.Core/Metadata.cs
@@ -41,11 +41,22 @@ using Grpc.Core.Utils;
 namespace Grpc.Core
 {
     /// <summary>
-    /// Provides access to read and write metadata values to be exchanged during a call.
+    /// A collection of metadata entries that can be exchanged during a call.
+    /// gRPC supports these types of metadata:
+    /// <list type="bullet">
+    /// <item><term>Request headers</term><description>are sent by the client at the beginning of a remote call before any request messages are sent.</description></item>
+    /// <item><term>Response headers</term><description>are sent by the server at the beginning of a remote call handler before any response messages are sent.</description></item>
+    /// <item><term>Response trailers</term><description>are sent by the server at the end of a remote call along with resulting call status.</description></item>
+    /// </list>
     /// </summary>
     public sealed class Metadata : IList<Metadata.Entry>
     {
         /// <summary>
+        /// All binary headers should have this suffix.
+        /// </summary>
+        public const string BinaryHeaderSuffix = "-bin";
+
+        /// <summary>
         /// An read-only instance of metadata containing no entries.
         /// </summary>
         public static readonly Metadata Empty = new Metadata().Freeze();
@@ -53,21 +64,19 @@ namespace Grpc.Core
         readonly List<Entry> entries;
         bool readOnly;
 
+        /// <summary>
+        /// Initializes a new instance of <c>Metadata</c>.
+        /// </summary>
         public Metadata()
         {
             this.entries = new List<Entry>();
         }
 
-        public Metadata(ICollection<Entry> entries)
-        {
-            this.entries = new List<Entry>(entries);
-        }
-
         /// <summary>
         /// Makes this object read-only.
         /// </summary>
         /// <returns>this object</returns>
-        public Metadata Freeze()
+        internal Metadata Freeze()
         {
             this.readOnly = true;
             return this;
@@ -181,23 +190,49 @@ namespace Grpc.Core
             private static readonly Encoding Encoding = Encoding.ASCII;
 
             readonly string key;
-            string value;
-            byte[] valueBytes;
+            readonly string value;
+            readonly byte[] valueBytes;
+
+            private Entry(string key, string value, byte[] valueBytes)
+            {
+                this.key = key;
+                this.value = value;
+                this.valueBytes = valueBytes;
+            }
 
+            /// <summary>
+            /// Initializes a new instance of the <see cref="Grpc.Core.Metadata.Entry"/> struct with a binary value.
+            /// </summary>
+            /// <param name="key">Metadata key, needs to have suffix indicating a binary valued metadata entry.</param>
+            /// <param name="valueBytes">Value bytes.</param>
             public Entry(string key, byte[] valueBytes)
             {
-                this.key = Preconditions.CheckNotNull(key, "key");
+                this.key = NormalizeKey(key);
+                Preconditions.CheckArgument(this.key.EndsWith(BinaryHeaderSuffix),
+                    "Key for binary valued metadata entry needs to have suffix indicating binary value.");
                 this.value = null;
-                this.valueBytes = Preconditions.CheckNotNull(valueBytes, "valueBytes");
+                Preconditions.CheckNotNull(valueBytes, "valueBytes");
+                this.valueBytes = new byte[valueBytes.Length];
+                Buffer.BlockCopy(valueBytes, 0, this.valueBytes, 0, valueBytes.Length);  // defensive copy to guarantee immutability
             }
 
+            /// <summary>
+            /// Initializes a new instance of the <see cref="Grpc.Core.Metadata.Entry"/> struct holding an ASCII value.
+            /// </summary>
+            /// <param name="key">Metadata key, must not use suffix indicating a binary valued metadata entry.</param>
+            /// <param name="value">Value string. Only ASCII characters are allowed.</param>
             public Entry(string key, string value)
             {
-                this.key = Preconditions.CheckNotNull(key, "key");
+                this.key = NormalizeKey(key);
+                Preconditions.CheckArgument(!this.key.EndsWith(BinaryHeaderSuffix),
+                    "Key for ASCII valued metadata entry cannot have suffix indicating binary value.");
                 this.value = Preconditions.CheckNotNull(value, "value");
                 this.valueBytes = null;
             }
 
+            /// <summary>
+            /// Gets the metadata entry key.
+            /// </summary>
             public string Key
             {
                 get
@@ -206,33 +241,86 @@ namespace Grpc.Core
                 }
             }
 
+            /// <summary>
+            /// Gets the binary value of this metadata entry.
+            /// </summary>
             public byte[] ValueBytes
             {
                 get
                 {
                     if (valueBytes == null)
                     {
-                        valueBytes = Encoding.GetBytes(value);
+                        return Encoding.GetBytes(value);
                     }
-                    return valueBytes;
+
+                    // defensive copy to guarantee immutability
+                    var bytes = new byte[valueBytes.Length];
+                    Buffer.BlockCopy(valueBytes, 0, bytes, 0, valueBytes.Length);
+                    return bytes;
                 }
             }
 
+            /// <summary>
+            /// Gets the string value of this metadata entry.
+            /// </summary>
             public string Value
             {
                 get
                 {
-                    if (value == null)
-                    {
-                        value = Encoding.GetString(valueBytes);
-                    }
-                    return value;
+                    Preconditions.CheckState(!IsBinary, "Cannot access string value of a binary metadata entry");
+                    return value ?? Encoding.GetString(valueBytes);
                 }
             }
-                
+
+            /// <summary>
+            /// Returns <c>true</c> if this entry is a binary-value entry.
+            /// </summary>
+            public bool IsBinary
+            {
+                get
+                {
+                    return value == null;
+                }
+            }
+
+            /// <summary>
+            /// Returns a <see cref="System.String"/> that represents the current <see cref="Grpc.Core.Metadata.Entry"/>.
+            /// </summary>
             public override string ToString()
             {
-                return string.Format("[Entry: key={0}, value={1}]", Key, Value);
+                if (IsBinary)
+                {
+                    return string.Format("[Entry: key={0}, valueBytes={1}]", key, valueBytes);
+                }
+                
+                return string.Format("[Entry: key={0}, value={1}]", key, value);
+            }
+
+            /// <summary>
+            /// Gets the serialized value for this entry. For binary metadata entries, this leaks
+            /// the internal <c>valueBytes</c> byte array and caller must not change contents of it.
+            /// </summary>
+            internal byte[] GetSerializedValueUnsafe()
+            {
+                return valueBytes ?? Encoding.GetBytes(value);
+            }
+
+            /// <summary>
+            /// Creates a binary value or ascii value metadata entry from data received from the native layer.
+            /// We trust C core to give us well-formed data, so we don't perform any checks or defensive copying.
+            /// </summary>
+            internal static Entry CreateUnsafe(string key, byte[] valueBytes)
+            {
+                if (key.EndsWith(BinaryHeaderSuffix))
+                {
+                    return new Entry(key, null, valueBytes);
+                }
+                return new Entry(key, Encoding.GetString(valueBytes), null);
+            }
+
+            private static string NormalizeKey(string key)
+            {
+                return Preconditions.CheckNotNull(key, "key").ToLower();
             }
         }
     }
diff --git a/src/csharp/Grpc.Core/Method.cs b/src/csharp/Grpc.Core/Method.cs
index 4c208b4a26..99162a7d5d 100644
--- a/src/csharp/Grpc.Core/Method.cs
+++ b/src/csharp/Grpc.Core/Method.cs
@@ -55,9 +55,38 @@ namespace Grpc.Core
     }
 
     /// <summary>
+    /// A non-generic representation of a remote method.
+    /// </summary>
+    public interface IMethod
+    {
+        /// <summary>
+        /// Gets the type of the method.
+        /// </summary>
+        MethodType Type { get; }
+
+        /// <summary>
+        /// Gets the name of the service to which this method belongs.
+        /// </summary>
+        string ServiceName { get; }
+
+        /// <summary>
+        /// Gets the unqualified name of the method.
+        /// </summary>
+        string Name { get; }
+
+        /// <summary>
+        /// Gets the fully qualified name of the method. On the server side, methods are dispatched
+        /// based on this name.
+        /// </summary>
+        string FullName { get; }
+    }
+
+    /// <summary>
     /// A description of a remote method.
     /// </summary>
-    public class Method<TRequest, TResponse>
+    /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this method.</typeparam>
+    public class Method<TRequest, TResponse> : IMethod
     {
         readonly MethodType type;
         readonly string serviceName;
diff --git a/src/csharp/Grpc.Core/Server.cs b/src/csharp/Grpc.Core/Server.cs
index c76f126026..7c94d21561 100644
--- a/src/csharp/Grpc.Core/Server.cs
+++ b/src/csharp/Grpc.Core/Server.cs
@@ -44,12 +44,14 @@ using Grpc.Core.Utils;
 namespace Grpc.Core
 {
     /// <summary>
-    /// A gRPC server.
+    /// gRPC server. A single server can server arbitrary number of services and can listen on more than one ports.
     /// </summary>
     public class Server
     {
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Server>();
 
+        readonly AtomicCounter activeCallCounter = new AtomicCounter();
+
         readonly ServiceDefinitionCollection serviceDefinitions;
         readonly ServerPortCollection ports;
         readonly GrpcEnvironment environment;
@@ -73,7 +75,7 @@ namespace Grpc.Core
         {
             this.serviceDefinitions = new ServiceDefinitionCollection(this);
             this.ports = new ServerPortCollection(this);
-            this.environment = GrpcEnvironment.GetInstance();
+            this.environment = GrpcEnvironment.AddRef();
             this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
             using (var channelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
@@ -106,6 +108,17 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// To allow awaiting termination of the server.
+        /// </summary>
+        public Task ShutdownTask
+        {
+            get
+            {
+                return shutdownTcs.Task;
+            }
+        }
+
+        /// <summary>
         /// Starts the server.
         /// </summary>
         public void Start()
@@ -136,18 +149,9 @@ namespace Grpc.Core
 
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             await shutdownTcs.Task;
-            handle.Dispose();
-        }
+            DisposeHandle();
 
-        /// <summary>
-        /// To allow awaiting termination of the server.
-        /// </summary>
-        public Task ShutdownTask
-        {
-            get
-            {
-                return shutdownTcs.Task;
-            }
+            await Task.Run(() => GrpcEnvironment.Release());
         }
 
         /// <summary>
@@ -166,7 +170,22 @@ namespace Grpc.Core
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             handle.CancelAllCalls();
             await shutdownTcs.Task;
-            handle.Dispose();
+            DisposeHandle();
+        }
+
+        internal void AddCallReference(object call)
+        {
+            activeCallCounter.Increment();
+
+            bool success = false;
+            handle.DangerousAddRef(ref success);
+            Preconditions.CheckState(success);
+        }
+
+        internal void RemoveCallReference(object call)
+        {
+            handle.DangerousRelease();
+            activeCallCounter.Decrement();
         }
 
         /// <summary>
@@ -227,6 +246,16 @@ namespace Grpc.Core
             }
         }
 
+        private void DisposeHandle()
+        {
+            var activeCallCount = activeCallCounter.Count;
+            if (activeCallCount > 0)
+            {
+                Logger.Warning("Server shutdown has finished but there are still {0} active calls for that server.", activeCallCount);
+            }
+            handle.Dispose();
+        }
+
         /// <summary>
         /// Selects corresponding handler for given call and handles the call.
         /// </summary>
@@ -254,7 +283,7 @@ namespace Grpc.Core
         {
             if (success)
             {
-                ServerRpcNew newRpc = ctx.GetServerRpcNew();
+                ServerRpcNew newRpc = ctx.GetServerRpcNew(this);
 
                 // after server shutdown, the callback returns with null call
                 if (!newRpc.Call.IsInvalid)
@@ -295,6 +324,9 @@ namespace Grpc.Core
                 server.AddServiceDefinitionInternal(serviceDefinition);
             }
 
+            /// <summary>
+            /// Gets enumerator for this collection.
+            /// </summary>
             public IEnumerator<ServerServiceDefinition> GetEnumerator()
             {
                 return server.serviceDefinitionsList.GetEnumerator();
@@ -340,6 +372,9 @@ namespace Grpc.Core
                 return Add(new ServerPort(host, port, credentials));
             }
 
+            /// <summary>
+            /// Gets enumerator for this collection.
+            /// </summary>
             public IEnumerator<ServerPort> GetEnumerator()
             {
                 return server.serverPortList.GetEnumerator();
diff --git a/src/csharp/Grpc.Core/ServerCallContext.cs b/src/csharp/Grpc.Core/ServerCallContext.cs
index 75d81c64f3..09a6b882a6 100644
--- a/src/csharp/Grpc.Core/ServerCallContext.cs
+++ b/src/csharp/Grpc.Core/ServerCallContext.cs
@@ -72,6 +72,13 @@ namespace Grpc.Core
             this.writeOptionsHolder = writeOptionsHolder;
         }
 
+        /// <summary>
+        /// Asynchronously sends response headers for the current call to the client. This method may only be invoked once for each call and needs to be invoked
+        /// before any response messages are written. Writing the first response message implicitly sends empty response headers if <c>WriteResponseHeadersAsync</c> haven't
+        /// been called yet.
+        /// </summary>
+        /// <param name="responseHeaders">The response headers to send.</param>
+        /// <returns>The task that finished once response headers have been written.</returns>
         public Task WriteResponseHeadersAsync(Metadata responseHeaders)
         {
             return writeHeadersFunc(responseHeaders);
@@ -186,6 +193,9 @@ namespace Grpc.Core
     /// </summary>
     public interface IHasWriteOptions
     {
+        /// <summary>
+        /// Gets or sets the write options.
+        /// </summary>
         WriteOptions WriteOptions { get; set; }
     }
 }
diff --git a/src/csharp/Grpc.Core/ServerMethods.cs b/src/csharp/Grpc.Core/ServerMethods.cs
index 1f119a80ff..728f77cde5 100644
--- a/src/csharp/Grpc.Core/ServerMethods.cs
+++ b/src/csharp/Grpc.Core/ServerMethods.cs
@@ -38,6 +38,8 @@ namespace Grpc.Core
     /// <summary>
     /// Server-side handler for unary call.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this method.</typeparam>
     public delegate Task<TResponse> UnaryServerMethod<TRequest, TResponse>(TRequest request, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
@@ -45,6 +47,8 @@ namespace Grpc.Core
     /// <summary>
     /// Server-side handler for client streaming call.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this method.</typeparam>
     public delegate Task<TResponse> ClientStreamingServerMethod<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
@@ -52,6 +56,8 @@ namespace Grpc.Core
     /// <summary>
     /// Server-side handler for server streaming call.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this method.</typeparam>
     public delegate Task ServerStreamingServerMethod<TRequest, TResponse>(TRequest request, IServerStreamWriter<TResponse> responseStream, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
@@ -59,6 +65,8 @@ namespace Grpc.Core
     /// <summary>
     /// Server-side handler for bidi streaming call.
     /// </summary>
+    /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+    /// <typeparam name="TResponse">Response message type for this method.</typeparam>
     public delegate Task DuplexStreamingServerMethod<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, IServerStreamWriter<TResponse> responseStream, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
diff --git a/src/csharp/Grpc.Core/ServerServiceDefinition.cs b/src/csharp/Grpc.Core/ServerServiceDefinition.cs
index 94b0a320c3..deb1431ca3 100644
--- a/src/csharp/Grpc.Core/ServerServiceDefinition.cs
+++ b/src/csharp/Grpc.Core/ServerServiceDefinition.cs
@@ -40,6 +40,8 @@ namespace Grpc.Core
 {
     /// <summary>
     /// Mapping of method names to server call handlers.
+    /// Normally, the <c>ServerServiceDefinition</c> objects will be created by the <c>BindService</c> factory method 
+    /// that is part of the autogenerated code for a protocol buffers service definition.
     /// </summary>
     public class ServerServiceDefinition
     {
@@ -58,21 +60,41 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Creates a new builder object for <c>ServerServiceDefinition</c>.
+        /// </summary>
+        /// <param name="serviceName">The service name.</param>
+        /// <returns>The builder object.</returns>
         public static Builder CreateBuilder(string serviceName)
         {
             return new Builder(serviceName);
         }
 
+        /// <summary>
+        /// Builder class for <see cref="ServerServiceDefinition"/>.
+        /// </summary>
         public class Builder
         {
             readonly string serviceName;
             readonly Dictionary<string, IServerCallHandler> callHandlers = new Dictionary<string, IServerCallHandler>();
 
+            /// <summary>
+            /// Creates a new instance of builder.
+            /// </summary>
+            /// <param name="serviceName">The service name.</param>
             public Builder(string serviceName)
             {
                 this.serviceName = serviceName;
             }
 
+            /// <summary>
+            /// Adds a definitions for a single request - single response method.
+            /// </summary>
+            /// <typeparam name="TRequest">The request message class.</typeparam>
+            /// <typeparam name="TResponse">The response message class.</typeparam>
+            /// <param name="method">The method.</param>
+            /// <param name="handler">The method handler.</param>
+            /// <returns>This builder instance.</returns>
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 UnaryServerMethod<TRequest, TResponse> handler)
@@ -83,6 +105,14 @@ namespace Grpc.Core
                 return this;
             }
 
+            /// <summary>
+            /// Adds a definitions for a client streaming method.
+            /// </summary>
+            /// <typeparam name="TRequest">The request message class.</typeparam>
+            /// <typeparam name="TResponse">The response message class.</typeparam>
+            /// <param name="method">The method.</param>
+            /// <param name="handler">The method handler.</param>
+            /// <returns>This builder instance.</returns>
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 ClientStreamingServerMethod<TRequest, TResponse> handler)
@@ -93,6 +123,14 @@ namespace Grpc.Core
                 return this;
             }
 
+            /// <summary>
+            /// Adds a definitions for a server streaming method.
+            /// </summary>
+            /// <typeparam name="TRequest">The request message class.</typeparam>
+            /// <typeparam name="TResponse">The response message class.</typeparam>
+            /// <param name="method">The method.</param>
+            /// <param name="handler">The method handler.</param>
+            /// <returns>This builder instance.</returns>
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 ServerStreamingServerMethod<TRequest, TResponse> handler)
@@ -103,6 +141,14 @@ namespace Grpc.Core
                 return this;
             }
 
+            /// <summary>
+            /// Adds a definitions for a bidirectional streaming method.
+            /// </summary>
+            /// <typeparam name="TRequest">The request message class.</typeparam>
+            /// <typeparam name="TResponse">The response message class.</typeparam>
+            /// <param name="method">The method.</param>
+            /// <param name="handler">The method handler.</param>
+            /// <returns>This builder instance.</returns>
             public Builder AddMethod<TRequest, TResponse>(
                 Method<TRequest, TResponse> method,
                 DuplexStreamingServerMethod<TRequest, TResponse> handler)
@@ -113,6 +159,10 @@ namespace Grpc.Core
                 return this;
             }
 
+            /// <summary>
+            /// Creates an immutable <c>ServerServiceDefinition</c> from this builder.
+            /// </summary>
+            /// <returns>The <c>ServerServiceDefinition</c> object.</returns>
             public ServerServiceDefinition Build()
             {
                 return new ServerServiceDefinition(callHandlers);
diff --git a/src/csharp/Grpc.Core/Utils/Preconditions.cs b/src/csharp/Grpc.Core/Utils/Preconditions.cs
index 374262f87a..a8ab603391 100644
--- a/src/csharp/Grpc.Core/Utils/Preconditions.cs
+++ b/src/csharp/Grpc.Core/Utils/Preconditions.cs
@@ -43,6 +43,7 @@ namespace Grpc.Core.Utils
         /// <summary>
         /// Throws <see cref="ArgumentException"/> if condition is false.
         /// </summary>
+        /// <param name="condition">The condition.</param>
         public static void CheckArgument(bool condition)
         {
             if (!condition)
@@ -54,6 +55,8 @@ namespace Grpc.Core.Utils
         /// <summary>
         /// Throws <see cref="ArgumentException"/> with given message if condition is false.
         /// </summary>
+        /// <param name="condition">The condition.</param>
+        /// <param name="errorMessage">The error message.</param>
         public static void CheckArgument(bool condition, string errorMessage)
         {
             if (!condition)
@@ -65,6 +68,7 @@ namespace Grpc.Core.Utils
         /// <summary>
         /// Throws <see cref="ArgumentNullException"/> if reference is null.
         /// </summary>
+        /// <param name="reference">The reference.</param>
         public static T CheckNotNull<T>(T reference)
         {
             if (reference == null)
@@ -77,6 +81,8 @@ namespace Grpc.Core.Utils
         /// <summary>
         /// Throws <see cref="ArgumentNullException"/> if reference is null.
         /// </summary>
+        /// <param name="reference">The reference.</param>
+        /// <param name="paramName">The parameter name.</param>
         public static T CheckNotNull<T>(T reference, string paramName)
         {
             if (reference == null)
@@ -89,6 +95,7 @@ namespace Grpc.Core.Utils
         /// <summary>
         /// Throws <see cref="InvalidOperationException"/> if condition is false.
         /// </summary>
+        /// <param name="condition">The condition.</param>
         public static void CheckState(bool condition)
         {
             if (!condition)
@@ -100,6 +107,8 @@ namespace Grpc.Core.Utils
         /// <summary>
         /// Throws <see cref="InvalidOperationException"/> with given message if condition is false.
         /// </summary>
+        /// <param name="condition">The condition.</param>
+        /// <param name="errorMessage">The error message.</param>
         public static void CheckState(bool condition, string errorMessage)
         {
             if (!condition)
diff --git a/src/csharp/Grpc.Core/WriteOptions.cs b/src/csharp/Grpc.Core/WriteOptions.cs
index 7ef3189d76..7523ada84a 100644
--- a/src/csharp/Grpc.Core/WriteOptions.cs
+++ b/src/csharp/Grpc.Core/WriteOptions.cs
@@ -66,11 +66,18 @@ namespace Grpc.Core
             
         private WriteFlags flags;
 
+        /// <summary>
+        /// Initializes a new instance of <c>WriteOptions</c> class.
+        /// </summary>
+        /// <param name="flags">The write flags.</param>
         public WriteOptions(WriteFlags flags = default(WriteFlags))
         {
             this.flags = flags;
         }
 
+        /// <summary>
+        /// Gets the write flags.
+        /// </summary>
         public WriteFlags Flags
         {
             get
diff --git a/src/csharp/Grpc.Examples.MathClient/MathClient.cs b/src/csharp/Grpc.Examples.MathClient/MathClient.cs
index 0df14984cb..01e4a80bab 100644
--- a/src/csharp/Grpc.Examples.MathClient/MathClient.cs
+++ b/src/csharp/Grpc.Examples.MathClient/MathClient.cs
@@ -39,23 +39,21 @@ namespace Math
     {
         public static void Main(string[] args)
         {
-            using (Channel channel = new Channel("127.0.0.1", 23456, Credentials.Insecure))
-            {
-                Math.IMathClient client = new Math.MathClient(channel);
-                MathExamples.DivExample(client);
+            var channel = new Channel("127.0.0.1", 23456, Credentials.Insecure);
+            Math.IMathClient client = new Math.MathClient(channel);
+            MathExamples.DivExample(client);
 
-                MathExamples.DivAsyncExample(client).Wait();
+            MathExamples.DivAsyncExample(client).Wait();
 
-                MathExamples.FibExample(client).Wait();
+            MathExamples.FibExample(client).Wait();
 
-                MathExamples.SumExample(client).Wait();
+            MathExamples.SumExample(client).Wait();
 
-                MathExamples.DivManyExample(client).Wait();
+            MathExamples.DivManyExample(client).Wait();
 
-                MathExamples.DependendRequestsExample(client).Wait();
-            }
+            MathExamples.DependendRequestsExample(client).Wait();
 
-            GrpcEnvironment.Shutdown();
+            channel.ShutdownAsync().Wait();
         }
     }
 }
diff --git a/src/csharp/Grpc.Examples.MathServer/MathServer.cs b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
index 1b71c60141..6e974a0871 100644
--- a/src/csharp/Grpc.Examples.MathServer/MathServer.cs
+++ b/src/csharp/Grpc.Examples.MathServer/MathServer.cs
@@ -56,7 +56,6 @@ namespace Math
             Console.ReadKey();
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
     }
 }
diff --git a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
index 91c82b586b..d8547758d2 100644
--- a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
+++ b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
@@ -68,9 +68,8 @@ namespace Math.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
diff --git a/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs b/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs
index 98e24698f3..95f742cc99 100644
--- a/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs
+++ b/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs
@@ -71,10 +71,9 @@ namespace Grpc.HealthCheck.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
diff --git a/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs b/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
index 0fad62d5f1..26c6445c35 100644
--- a/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
@@ -95,6 +95,12 @@ namespace Grpc.HealthCheck
             }
         }
 
+        /// <summary>
+        /// Performs a health status check.
+        /// </summary>
+        /// <param name="request">The check request.</param>
+        /// <param name="context">The call context.</param>
+        /// <returns>The asynchronous response.</returns>
         public Task<HealthCheckResponse> Check(HealthCheckRequest request, ServerCallContext context)
         {
             lock (myLock)
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
index 3ea1539230..ed51af1942 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
@@ -41,10 +41,11 @@ using Grpc.Auth;
 using Grpc.Core;
 using Grpc.Core.Utils;
 using Grpc.Testing;
-using NUnit.Framework;
 using Google.Protobuf;
 using Google.Apis.Auth.OAuth2;
 
+using NUnit.Framework;
+
 namespace Grpc.IntegrationTesting
 {
     public class InteropClient
@@ -118,12 +119,10 @@ namespace Grpc.IntegrationTesting
                 };
             }
 
-            using (Channel channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions))
-            {
-                TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
-                await RunTestCaseAsync(options.testCase, client);
-            }
-            GrpcEnvironment.Shutdown();
+            var channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions);
+            TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
+            await RunTestCaseAsync(options.testCase, client);
+            channel.ShutdownAsync().Wait();
         }
 
         private async Task RunTestCaseAsync(string testCase, TestService.TestServiceClient client)
@@ -169,6 +168,9 @@ namespace Grpc.IntegrationTesting
                 case "cancel_after_first_response":
                     await RunCancelAfterFirstResponseAsync(client);
                     break;
+                case "timeout_on_sleeping_server":
+                    await RunTimeoutOnSleepingServerAsync(client);
+                    break;
                 case "benchmark_empty_unary":
                     RunBenchmarkEmptyUnary(client);
                     break;
@@ -317,7 +319,7 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("running service_account_creds");
             var credential = await GoogleCredential.GetApplicationDefaultAsync();
             credential = credential.CreateScoped(new[] { AuthScope });
-            client.HeaderInterceptor = OAuth2Interceptors.FromCredential(credential);
+            client.HeaderInterceptor = AuthInterceptors.FromCredential(credential);
 
             var request = new SimpleRequest
             {
@@ -342,7 +344,7 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("running compute_engine_creds");
             var credential = await GoogleCredential.GetApplicationDefaultAsync();
             Assert.IsFalse(credential.IsCreateScopedRequired);
-            client.HeaderInterceptor = OAuth2Interceptors.FromCredential(credential);
+            client.HeaderInterceptor = AuthInterceptors.FromCredential(credential);
             
             var request = new SimpleRequest
             {
@@ -368,7 +370,7 @@ namespace Grpc.IntegrationTesting
             var credential = await GoogleCredential.GetApplicationDefaultAsync();
             // check this a credential with scope support, but don't add the scope.
             Assert.IsTrue(credential.IsCreateScopedRequired);
-            client.HeaderInterceptor = OAuth2Interceptors.FromCredential(credential);
+            client.HeaderInterceptor = AuthInterceptors.FromCredential(credential);
 
             var request = new SimpleRequest
             {
@@ -393,7 +395,7 @@ namespace Grpc.IntegrationTesting
             ITokenAccess credential = (await GoogleCredential.GetApplicationDefaultAsync()).CreateScoped(new[] { AuthScope });
             string oauth2Token = await credential.GetAccessTokenForRequestAsync();
 
-            client.HeaderInterceptor = OAuth2Interceptors.FromAccessToken(oauth2Token);
+            client.HeaderInterceptor = AuthInterceptors.FromAccessToken(oauth2Token);
 
             var request = new SimpleRequest
             {
@@ -414,7 +416,7 @@ namespace Grpc.IntegrationTesting
 
             ITokenAccess credential = (await GoogleCredential.GetApplicationDefaultAsync()).CreateScoped(new[] { AuthScope });
             string oauth2Token = await credential.GetAccessTokenForRequestAsync();
-            var headerInterceptor = OAuth2Interceptors.FromAccessToken(oauth2Token);
+            var headerInterceptor = AuthInterceptors.FromAccessToken(oauth2Token);
 
             var request = new SimpleRequest
             {
@@ -423,7 +425,7 @@ namespace Grpc.IntegrationTesting
             };
 
             var headers = new Metadata();
-            headerInterceptor("", headers);
+            headerInterceptor(null, "", headers);
             var response = client.UnaryCall(request, headers: headers);
 
             Assert.AreEqual(AuthScopeResponse, response.OauthScope);
@@ -474,6 +476,28 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("Passed!");
         }
 
+        public static async Task RunTimeoutOnSleepingServerAsync(TestService.ITestServiceClient client)
+        {
+            Console.WriteLine("running timeout_on_sleeping_server");
+
+            var deadline = DateTime.UtcNow.AddMilliseconds(1);
+            using (var call = client.FullDuplexCall(deadline: deadline))
+            {
+                try
+                {
+                    await call.RequestStream.WriteAsync(new StreamingOutputCallRequest { Payload = CreateZerosPayload(27182) });
+                }
+                catch (InvalidOperationException)
+                {
+                    // Deadline was reached before write has started. Eat the exception and continue.
+                }
+
+                var ex = Assert.Throws<RpcException>(async () => await call.ResponseStream.MoveNext());
+                Assert.AreEqual(StatusCode.DeadlineExceeded, ex.Status.StatusCode);
+            }
+            Console.WriteLine("Passed!");
+        }
+
         // This is not an official interop test, but it's useful.
         public static void RunBenchmarkEmptyUnary(TestService.ITestServiceClient client)
         {
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs b/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
index a827aedbdd..7bc17a207f 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
@@ -75,9 +75,8 @@ namespace Grpc.IntegrationTesting
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -127,5 +126,11 @@ namespace Grpc.IntegrationTesting
         {
             await InteropClient.RunCancelAfterFirstResponseAsync(client);
         }
+
+        [Test]
+        public async Task TimeoutOnSleepingServerAsync()
+        {
+            await InteropClient.RunTimeoutOnSleepingServerAsync(client);
+        }
     }
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropServer.cs b/src/csharp/Grpc.IntegrationTesting/InteropServer.cs
index dea0ce752b..718278f30a 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropServer.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropServer.cs
@@ -106,8 +106,6 @@ namespace Grpc.IntegrationTesting
             server.Start();
 
             server.ShutdownTask.Wait();
-
-            GrpcEnvironment.Shutdown();
         }
 
         private static ServerOptions ParseArguments(string[] args)
diff --git a/src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs b/src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs
index 08a2d9b31c..37b2518c21 100644
--- a/src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs
@@ -85,9 +85,8 @@ namespace Grpc.IntegrationTesting
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
diff --git a/src/csharp/doc/grpc_csharp_public.shfbproj b/src/csharp/doc/grpc_csharp_public.shfbproj
index 05c93f4a13..d9b9749819 100644
--- a/src/csharp/doc/grpc_csharp_public.shfbproj
+++ b/src/csharp/doc/grpc_csharp_public.shfbproj
@@ -18,7 +18,8 @@
     <Language>en-US</Language>
     <DocumentationSources>
       <DocumentationSource sourceFile="..\Grpc.Auth\Grpc.Auth.csproj" />
-<DocumentationSource sourceFile="..\Grpc.Core\Grpc.Core.csproj" /></DocumentationSources>
+      <DocumentationSource sourceFile="..\Grpc.Core\Grpc.Core.csproj" />
+    </DocumentationSources>
     <BuildAssemblerVerbosity>OnlyWarningsAndErrors</BuildAssemblerVerbosity>
     <HelpFileFormat>Website</HelpFileFormat>
     <IndentHtml>False</IndentHtml>
@@ -37,6 +38,15 @@
     <HelpTitle>gRPC C#</HelpTitle>
     <ContentPlacement>AboveNamespaces</ContentPlacement>
     <HtmlHelpName>Documentation</HtmlHelpName>
+    <NamespaceSummaries>
+      <NamespaceSummaryItem name="Grpc.Auth" isDocumented="True">Provides OAuth2 based authentication for gRPC. &lt;c&gt;Grpc.Auth&lt;/c&gt; currently consists of a set of very lightweight wrappers and uses C# &lt;a href="https://www.nuget.org/packages/Google.Apis.Auth/"&gt;Google.Apis.Auth&lt;/a&gt; library.</NamespaceSummaryItem>
+<NamespaceSummaryItem name="Grpc.Core" isDocumented="True">Main namespace for gRPC C# functionality. Contains concepts representing both client side and server side gRPC logic.
+
+&lt;seealso cref="Grpc.Core.Channel"/&gt; 
+&lt;seealso cref="Grpc.Core.Server"/&gt;</NamespaceSummaryItem>
+<NamespaceSummaryItem name="Grpc.Core.Logging" isDocumented="True">Provides functionality to redirect gRPC logs to application-specified destination.</NamespaceSummaryItem>
+<NamespaceSummaryItem name="Grpc.Core.Utils" isDocumented="True">Various utilities for gRPC C#.</NamespaceSummaryItem></NamespaceSummaries>
+    <MissingTags>Summary, Parameter, AutoDocumentCtors, Namespace, TypeParameter, AutoDocumentDispose</MissingTags>
   </PropertyGroup>
   <!-- There are no properties for these groups.  AnyCPU needs to appear in order for Visual Studio to perform
 			 the build.  The others are optional common platform types that may appear. -->
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index bf2bbd873b..489e219c49 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -510,22 +510,27 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[1].data.send_message = ctx->send_message;
   ops[1].flags = write_flags;
+  ops[1].reserved = NULL;
 
   ops[2].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   ops[2].flags = 0;
+  ops[2].reserved = NULL;
 
   ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
   ops[3].flags = 0;
+  ops[3].reserved = NULL;
 
   ops[4].op = GRPC_OP_RECV_MESSAGE;
   ops[4].data.recv_message = &(ctx->recv_message);
   ops[4].flags = 0;
+  ops[4].reserved = NULL;
 
   ops[5].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[5].data.recv_status_on_client.trailing_metadata =
@@ -538,6 +543,7 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[5].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
   ops[5].flags = 0;
+  ops[5].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -556,14 +562,17 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
   ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   ops[2].op = GRPC_OP_RECV_MESSAGE;
   ops[2].data.recv_message = &(ctx->recv_message);
   ops[2].flags = 0;
+  ops[2].reserved = NULL;
 
   ops[3].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[3].data.recv_status_on_client.trailing_metadata =
@@ -576,6 +585,7 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
   ops[3].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
   ops[3].flags = 0;
+  ops[3].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -585,7 +595,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
     grpc_call *call, grpcsharp_batch_context *ctx, const char *send_buffer,
     size_t send_buffer_len, grpc_metadata_array *initial_metadata, gpr_uint32 write_flags) {
   /* TODO: don't use magic number */
-  grpc_op ops[5];
+  grpc_op ops[4];
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -593,30 +603,30 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[1].data.send_message = ctx->send_message;
   ops[1].flags = write_flags;
+  ops[1].reserved = NULL;
 
   ops[2].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   ops[2].flags = 0;
+  ops[2].reserved = NULL;
 
-  ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
-  ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
-  ops[3].flags = 0;
-
-  ops[4].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[4].data.recv_status_on_client.trailing_metadata =
+  ops[3].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
+  ops[3].data.recv_status_on_client.trailing_metadata =
       &(ctx->recv_status_on_client.trailing_metadata);
-  ops[4].data.recv_status_on_client.status =
+  ops[3].data.recv_status_on_client.status =
       &(ctx->recv_status_on_client.status);
   /* not using preallocation for status_details */
-  ops[4].data.recv_status_on_client.status_details =
+  ops[3].data.recv_status_on_client.status_details =
       &(ctx->recv_status_on_client.status_details);
-  ops[4].data.recv_status_on_client.status_details_capacity =
+  ops[3].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
-  ops[4].flags = 0;
+  ops[3].flags = 0;
+  ops[3].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -627,7 +637,7 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
                                       grpcsharp_batch_context *ctx,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
-  grpc_op ops[3];
+  grpc_op ops[2];
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -635,27 +645,38 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
-  ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
-  ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
-  ops[1].flags = 0;
-
-  ops[2].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[2].data.recv_status_on_client.trailing_metadata =
+  ops[1].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
+  ops[1].data.recv_status_on_client.trailing_metadata =
       &(ctx->recv_status_on_client.trailing_metadata);
-  ops[2].data.recv_status_on_client.status =
+  ops[1].data.recv_status_on_client.status =
       &(ctx->recv_status_on_client.status);
   /* not using preallocation for status_details */
-  ops[2].data.recv_status_on_client.status_details =
+  ops[1].data.recv_status_on_client.status_details =
       &(ctx->recv_status_on_client.status_details);
-  ops[2].data.recv_status_on_client.status_details_capacity =
+  ops[1].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
-  ops[2].flags = 0;
+  ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
 }
 
+GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_recv_initial_metadata(
+	grpc_call *call, grpcsharp_batch_context *ctx) {
+	/* TODO: don't use magic number */
+	grpc_op ops[1];
+	ops[0].op = GRPC_OP_RECV_INITIAL_METADATA;
+	ops[0].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+	ops[0].flags = 0;
+	ops[0].reserved = NULL;
+
+	return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
+		NULL);
+}
+
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
                             const char *send_buffer, size_t send_buffer_len,
@@ -668,10 +689,12 @@ grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[0].data.send_message = ctx->send_message;
   ops[0].flags = write_flags;
+  ops[0].reserved = NULL;
   ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
   ops[1].data.send_initial_metadata.count = 0;
   ops[1].data.send_initial_metadata.metadata = NULL;
   ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, nops, ctx, NULL);
 }
@@ -683,6 +706,7 @@ grpcsharp_call_send_close_from_client(grpc_call *call,
   grpc_op ops[1];
   ops[0].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -706,10 +730,12 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
   ops[0].data.send_status_from_server.trailing_metadata =
       ctx->send_status_from_server.trailing_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
   ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
   ops[1].data.send_initial_metadata.count = 0;
   ops[1].data.send_initial_metadata.metadata = NULL;
   ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, nops, ctx, NULL);
 }
@@ -721,6 +747,7 @@ grpcsharp_call_recv_message(grpc_call *call, grpcsharp_batch_context *ctx) {
   ops[0].op = GRPC_OP_RECV_MESSAGE;
   ops[0].data.recv_message = &(ctx->recv_message);
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
 }
@@ -733,6 +760,7 @@ grpcsharp_call_start_serverside(grpc_call *call, grpcsharp_batch_context *ctx) {
   ops[0].data.recv_close_on_server.cancelled =
       (&ctx->recv_close_on_server_cancelled);
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -751,6 +779,7 @@ grpcsharp_call_send_initial_metadata(grpc_call *call,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
diff --git a/src/node/README.md b/src/node/README.md
index 7d3d8c7fa1..b6411537c7 100644
--- a/src/node/README.md
+++ b/src/node/README.md
@@ -5,11 +5,35 @@ Alpha : Ready for early adopters
 
 ## PREREQUISITES
 - `node`: This requires `node` to be installed. If you instead have the `nodejs` executable on Debian, you should install the [`nodejs-legacy`](https://packages.debian.org/sid/nodejs-legacy) package.
-- [homebrew][] on Mac OS X, [linuxbrew][] on Linux.  These simplify the installation of the gRPC C core.
+- [homebrew][] on Mac OS X.  These simplify the installation of the gRPC C core.
 
 ## INSTALLATION
-On Mac OS X, install [homebrew][]. On Linux, install [linuxbrew][].
-Run the following command to install gRPC Node.js.
+
+**Linux (Debian):**
+
+Add [Debian unstable][] to your `sources.list` file. Example:
+
+```sh
+echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+sudo tee -a /etc/apt/sources.list
+```
+
+Install the gRPC Debian package
+
+```sh
+sudo apt-get update
+sudo apt-get install libgrpc-dev
+```
+
+Install the gRPC NPM package
+
+```sh
+npm install grpc
+```
+
+**Mac OS X**
+
+Install [homebrew][]. Run the following command to install gRPC Node.js.
 ```sh
 $ curl -fsSL https://goo.gl/getgrpc | bash -s nodejs
 ```
@@ -88,5 +112,5 @@ ServerCredentials
 An object with factory methods for creating credential objects for servers.
 
 [homebrew]:http://brew.sh
-[linuxbrew]:https://github.com/Homebrew/linuxbrew#installation
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
+[Debian unstable]:https://www.debian.org/releases/sid/
diff --git a/src/node/examples/perf_test.js b/src/node/examples/perf_test.js
index 214b9384d5..ba8fbf88d2 100644
--- a/src/node/examples/perf_test.js
+++ b/src/node/examples/perf_test.js
@@ -40,7 +40,7 @@ var interop_server = require('../interop/interop_server.js');
 
 function runTest(iterations, callback) {
   var testServer = interop_server.getServer(0, false);
-  testServer.server.listen();
+  testServer.server.start();
   var client = new testProto.TestService('localhost:' + testServer.port,
                                          grpc.Credentials.createInsecure());
 
diff --git a/src/node/examples/qps_test.js b/src/node/examples/qps_test.js
index 1ce4dbe070..ec968b8540 100644
--- a/src/node/examples/qps_test.js
+++ b/src/node/examples/qps_test.js
@@ -60,7 +60,7 @@ var interop_server = require('../interop/interop_server.js');
  */
 function runTest(concurrent_calls, seconds, callback) {
   var testServer = interop_server.getServer(0, false);
-  testServer.server.listen();
+  testServer.server.start();
   var client = new testProto.TestService('localhost:' + testServer.port,
                                          grpc.Credentials.createInsecure());
 
diff --git a/src/node/examples/route_guide_server.js b/src/node/examples/route_guide_server.js
index bb8e79b5bd..465b32f54f 100644
--- a/src/node/examples/route_guide_server.js
+++ b/src/node/examples/route_guide_server.js
@@ -248,7 +248,7 @@ if (require.main === module) {
       throw err;
     }
     feature_list = JSON.parse(data);
-    routeServer.listen();
+    routeServer.start();
   });
 }
 
diff --git a/src/node/examples/stock_server.js b/src/node/examples/stock_server.js
index dfcfe30eb4..12e5479584 100644
--- a/src/node/examples/stock_server.js
+++ b/src/node/examples/stock_server.js
@@ -81,7 +81,7 @@ stockServer.addProtoService(examples.Stock.service, {
 
 if (require.main === module) {
   stockServer.bind('0.0.0.0:50051', grpc.ServerCredentials.createInsecure());
-  stockServer.listen();
+  stockServer.start();
 }
 
 module.exports = stockServer;
diff --git a/src/node/ext/call.cc b/src/node/ext/call.cc
index 6fc1bc424f..18858fa334 100644
--- a/src/node/ext/call.cc
+++ b/src/node/ext/call.cc
@@ -207,6 +207,13 @@ class SendMessageOp : public Op {
     if (!::node::Buffer::HasInstance(value)) {
       return false;
     }
+    Handle<Object> object_value = value->ToObject();
+    if (object_value->HasOwnProperty(NanNew("grpcWriteFlags"))) {
+      Handle<Value> flag_value = object_value->Get(NanNew("grpcWriteFlags"));
+      if (flag_value->IsUint32()) {
+        out->flags = flag_value->Uint32Value() & GRPC_WRITE_USED_MASK;
+      }
+    }
     out->data.send_message = BufferToByteBuffer(value);
     Persistent<Value> *handle = new Persistent<Value>();
     NanAssignPersistent(*handle, value);
@@ -457,10 +464,6 @@ void Call::Init(Handle<Object> exports) {
                           NanNew<FunctionTemplate>(GetPeer)->GetFunction());
   NanAssignPersistent(fun_tpl, tpl);
   Handle<Function> ctr = tpl->GetFunction();
-  ctr->Set(NanNew("WRITE_BUFFER_HINT"),
-           NanNew<Uint32, uint32_t>(GRPC_WRITE_BUFFER_HINT));
-  ctr->Set(NanNew("WRITE_NO_COMPRESS"),
-           NanNew<Uint32, uint32_t>(GRPC_WRITE_NO_COMPRESS));
   exports->Set(NanNew("Call"), ctr);
   constructor = new NanCallback(ctr);
 }
@@ -502,6 +505,22 @@ NAN_METHOD(Call::New) {
         return NanThrowTypeError(
             "Call's third argument must be a date or a number");
       }
+      // These arguments are at the end because they are optional
+      grpc_call *parent_call = NULL;
+      if (Call::HasInstance(args[4])) {
+        Call *parent_obj = ObjectWrap::Unwrap<Call>(args[4]->ToObject());
+        parent_call = parent_obj->wrapped_call;
+      } else if (!(args[4]->IsUndefined() || args[4]->IsNull())) {
+        return NanThrowTypeError(
+            "Call's fifth argument must be another call, if provided");
+      }
+      gpr_uint32 propagate_flags = GRPC_PROPAGATE_DEFAULTS;
+      if (args[5]->IsUint32()) {
+        propagate_flags = args[5]->Uint32Value();
+      } else if (!(args[5]->IsUndefined() || args[5]->IsNull())) {
+        return NanThrowTypeError(
+            "Call's sixth argument must be propagate flags, if provided");
+      }
       Handle<Object> channel_object = args[0]->ToObject();
       Channel *channel = ObjectWrap::Unwrap<Channel>(channel_object);
       if (channel->GetWrappedChannel() == NULL) {
@@ -514,12 +533,12 @@ NAN_METHOD(Call::New) {
       if (args[3]->IsString()) {
         NanUtf8String host_override(args[3]);
         wrapped_call = grpc_channel_create_call(
-            wrapped_channel, NULL, GRPC_PROPAGATE_DEFAULTS,
+            wrapped_channel, parent_call, propagate_flags,
             CompletionQueueAsyncWorker::GetQueue(), *method,
             *host_override, MillisecondsToTimespec(deadline), NULL);
       } else if (args[3]->IsUndefined() || args[3]->IsNull()) {
         wrapped_call = grpc_channel_create_call(
-            wrapped_channel, NULL, GRPC_PROPAGATE_DEFAULTS,
+            wrapped_channel, parent_call, propagate_flags,
             CompletionQueueAsyncWorker::GetQueue(), *method,
             NULL, MillisecondsToTimespec(deadline), NULL);
       } else {
@@ -565,6 +584,7 @@ NAN_METHOD(Call::StartBatch) {
     uint32_t type = keys->Get(i)->Uint32Value();
     ops[i].op = static_cast<grpc_op_type>(type);
     ops[i].flags = 0;
+    ops[i].reserved = NULL;
     switch (type) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         op.reset(new SendMetadataOp());
@@ -603,7 +623,7 @@ NAN_METHOD(Call::StartBatch) {
       call->wrapped_call, &ops[0], nops, new struct tag(
           callback, op_vector.release(), resources), NULL);
   if (error != GRPC_CALL_OK) {
-    return NanThrowError("startBatch failed", error);
+    return NanThrowError(nanErrorWithCode("startBatch failed", error));
   }
   CompletionQueueAsyncWorker::Next();
   NanReturnUndefined();
@@ -617,7 +637,7 @@ NAN_METHOD(Call::Cancel) {
   Call *call = ObjectWrap::Unwrap<Call>(args.This());
   grpc_call_error error = grpc_call_cancel(call->wrapped_call, NULL);
   if (error != GRPC_CALL_OK) {
-    return NanThrowError("cancel failed", error);
+    return NanThrowError(nanErrorWithCode("cancel failed", error));
   }
   NanReturnUndefined();
 }
diff --git a/src/node/ext/call.h b/src/node/ext/call.h
index 6acda76197..ef6e5fcd21 100644
--- a/src/node/ext/call.h
+++ b/src/node/ext/call.h
@@ -51,6 +51,19 @@ namespace node {
 using std::unique_ptr;
 using std::shared_ptr;
 
+/**
+ * Helper function for throwing errors with a grpc_call_error value.
+ * Modified from the answer by Gus Goose to
+ * http://stackoverflow.com/questions/31794200.
+ */
+inline v8::Local<v8::Value> nanErrorWithCode(const char *msg,
+                                             grpc_call_error code) {
+    NanEscapableScope();
+    v8::Local<v8::Object> err = NanError(msg).As<v8::Object>();
+    err->Set(NanNew("code"), NanNew<v8::Uint32>(code));
+    return NanEscapeScope(err);
+}
+
 v8::Handle<v8::Value> ParseMetadata(const grpc_metadata_array *metadata_array);
 
 class PersistentHolder {
diff --git a/src/node/ext/node_grpc.cc b/src/node/ext/node_grpc.cc
index 331ccb60d6..0cf30da922 100644
--- a/src/node/ext/node_grpc.cc
+++ b/src/node/ext/node_grpc.cc
@@ -159,6 +159,25 @@ void InitOpTypeConstants(Handle<Object> exports) {
   op_type->Set(NanNew("RECV_CLOSE_ON_SERVER"), RECV_CLOSE_ON_SERVER);
 }
 
+void InitPropagateConstants(Handle<Object> exports) {
+  NanScope();
+  Handle<Object> propagate = NanNew<Object>();
+  exports->Set(NanNew("propagate"), propagate);
+  Handle<Value> DEADLINE(NanNew<Uint32, uint32_t>(GRPC_PROPAGATE_DEADLINE));
+  propagate->Set(NanNew("DEADLINE"), DEADLINE);
+  Handle<Value> CENSUS_STATS_CONTEXT(
+      NanNew<Uint32, uint32_t>(GRPC_PROPAGATE_CENSUS_STATS_CONTEXT));
+  propagate->Set(NanNew("CENSUS_STATS_CONTEXT"), CENSUS_STATS_CONTEXT);
+  Handle<Value> CENSUS_TRACING_CONTEXT(
+      NanNew<Uint32, uint32_t>(GRPC_PROPAGATE_CENSUS_TRACING_CONTEXT));
+  propagate->Set(NanNew("CENSUS_TRACING_CONTEXT"), CENSUS_TRACING_CONTEXT);
+  Handle<Value> CANCELLATION(
+      NanNew<Uint32, uint32_t>(GRPC_PROPAGATE_CANCELLATION));
+  propagate->Set(NanNew("CANCELLATION"), CANCELLATION);
+  Handle<Value> DEFAULTS(NanNew<Uint32, uint32_t>(GRPC_PROPAGATE_DEFAULTS));
+  propagate->Set(NanNew("DEFAULTS"), DEFAULTS);
+}
+
 void InitConnectivityStateConstants(Handle<Object> exports) {
   NanScope();
   Handle<Object> channel_state = NanNew<Object>();
@@ -177,13 +196,25 @@ void InitConnectivityStateConstants(Handle<Object> exports) {
   channel_state->Set(NanNew("FATAL_FAILURE"), FATAL_FAILURE);
 }
 
+void InitWriteFlags(Handle<Object> exports) {
+  NanScope();
+  Handle<Object> write_flags = NanNew<Object>();
+  exports->Set(NanNew("writeFlags"), write_flags);
+  Handle<Value> BUFFER_HINT(NanNew<Uint32, uint32_t>(GRPC_WRITE_BUFFER_HINT));
+  write_flags->Set(NanNew("BUFFER_HINT"), BUFFER_HINT);
+  Handle<Value> NO_COMPRESS(NanNew<Uint32, uint32_t>(GRPC_WRITE_NO_COMPRESS));
+  write_flags->Set(NanNew("NO_COMPRESS"), NO_COMPRESS);
+}
+
 void init(Handle<Object> exports) {
   NanScope();
   grpc_init();
   InitStatusConstants(exports);
   InitCallErrorConstants(exports);
   InitOpTypeConstants(exports);
+  InitPropagateConstants(exports);
   InitConnectivityStateConstants(exports);
+  InitWriteFlags(exports);
 
   grpc::node::Call::Init(exports);
   grpc::node::Channel::Init(exports);
diff --git a/src/node/ext/server.cc b/src/node/ext/server.cc
index 8e39644846..01217bce79 100644
--- a/src/node/ext/server.cc
+++ b/src/node/ext/server.cc
@@ -235,7 +235,7 @@ NAN_METHOD(Server::RequestCall) {
       new struct tag(new NanCallback(args[0].As<Function>()), ops.release(),
                      shared_ptr<Resources>(nullptr)));
   if (error != GRPC_CALL_OK) {
-    return NanThrowError("requestCall failed", error);
+    return NanThrowError(nanErrorWithCode("requestCall failed", error));
   }
   CompletionQueueAsyncWorker::Next();
   NanReturnUndefined();
diff --git a/src/node/ext/server_credentials.cc b/src/node/ext/server_credentials.cc
index 1b8e7b43fb..6e17197e16 100644
--- a/src/node/ext/server_credentials.cc
+++ b/src/node/ext/server_credentials.cc
@@ -41,6 +41,7 @@
 namespace grpc {
 namespace node {
 
+using v8::Array;
 using v8::Exception;
 using v8::External;
 using v8::Function;
@@ -52,6 +53,7 @@ using v8::Local;
 using v8::Object;
 using v8::ObjectTemplate;
 using v8::Persistent;
+using v8::String;
 using v8::Value;
 
 NanCallback *ServerCredentials::constructor;
@@ -122,25 +124,66 @@ NAN_METHOD(ServerCredentials::CreateSsl) {
   // TODO: have the node API support multiple key/cert pairs.
   NanScope();
   char *root_certs = NULL;
-  grpc_ssl_pem_key_cert_pair key_cert_pair;
   if (::node::Buffer::HasInstance(args[0])) {
     root_certs = ::node::Buffer::Data(args[0]);
   } else if (!(args[0]->IsNull() || args[0]->IsUndefined())) {
     return NanThrowTypeError(
         "createSSl's first argument must be a Buffer if provided");
   }
-  if (!::node::Buffer::HasInstance(args[1])) {
-    return NanThrowTypeError("createSsl's second argument must be a Buffer");
+  if (!args[1]->IsArray()) {
+    return NanThrowTypeError(
+        "createSsl's second argument must be a list of objects");
+  }
+  int force_client_auth = 0;
+  if (args[2]->IsBoolean()) {
+    force_client_auth = (int)args[2]->BooleanValue();
+  } else if (!(args[2]->IsUndefined() || args[2]->IsNull())) {
+    return NanThrowTypeError(
+        "createSsl's third argument must be a boolean if provided");
   }
-  key_cert_pair.private_key = ::node::Buffer::Data(args[1]);
-  if (!::node::Buffer::HasInstance(args[2])) {
-    return NanThrowTypeError("createSsl's third argument must be a Buffer");
+  Handle<Array> pair_list = Local<Array>::Cast(args[1]);
+  uint32_t key_cert_pair_count = pair_list->Length();
+  grpc_ssl_pem_key_cert_pair *key_cert_pairs = new grpc_ssl_pem_key_cert_pair[
+      key_cert_pair_count];
+
+  Handle<String> key_key = NanNew("private_key");
+  Handle<String> cert_key = NanNew("cert_chain");
+
+  for(uint32_t i = 0; i < key_cert_pair_count; i++) {
+    if (!pair_list->Get(i)->IsObject()) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("Key/cert pairs must be objects");
+    }
+    Handle<Object> pair_obj = pair_list->Get(i)->ToObject();
+    if (!pair_obj->HasOwnProperty(key_key)) {
+      delete key_cert_pairs;
+      return NanThrowTypeError(
+          "Key/cert pairs must have a private_key and a cert_chain");
+    }
+    if (!pair_obj->HasOwnProperty(cert_key)) {
+      delete key_cert_pairs;
+      return NanThrowTypeError(
+          "Key/cert pairs must have a private_key and a cert_chain");
+    }
+    if (!::node::Buffer::HasInstance(pair_obj->Get(key_key))) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("private_key must be a Buffer");
+    }
+    if (!::node::Buffer::HasInstance(pair_obj->Get(cert_key))) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("cert_chain must be a Buffer");
+    }
+    key_cert_pairs[i].private_key = ::node::Buffer::Data(
+        pair_obj->Get(key_key));
+    key_cert_pairs[i].cert_chain = ::node::Buffer::Data(
+        pair_obj->Get(cert_key));
   }
-  key_cert_pair.cert_chain = ::node::Buffer::Data(args[2]);
-  // TODO Add a force_client_auth parameter and pass it as the last parameter
-  // here.
   grpc_server_credentials *creds =
-      grpc_ssl_server_credentials_create(root_certs, &key_cert_pair, 1, 0);
+      grpc_ssl_server_credentials_create(root_certs,
+                                         key_cert_pairs,
+                                         key_cert_pair_count,
+                                         force_client_auth);
+  delete key_cert_pairs;
   if (creds == NULL) {
     NanReturnNull();
   }
diff --git a/src/node/health_check/health.js b/src/node/health_check/health.js
index 87e00197fe..84d7e0568e 100644
--- a/src/node/health_check/health.js
+++ b/src/node/health_check/health.js
@@ -45,17 +45,13 @@ function HealthImplementation(statusMap) {
   this.statusMap = _.clone(statusMap);
 }
 
-HealthImplementation.prototype.setStatus = function(host, service, status) {
-  if (!this.statusMap[host]) {
-    this.statusMap[host] = {};
-  }
-  this.statusMap[host][service] = status;
+HealthImplementation.prototype.setStatus = function(service, status) {
+  this.statusMap[service] = status;
 };
 
 HealthImplementation.prototype.check = function(call, callback){
-  var host = call.request.host;
   var service = call.request.service;
-  var status = _.get(this.statusMap, [host, service], null);
+  var status = _.get(this.statusMap, service, null);
   if (status === null) {
     callback({code:grpc.status.NOT_FOUND});
   } else {
diff --git a/src/node/health_check/health.proto b/src/node/health_check/health.proto
index d31df1e0a7..57f4aaa9c0 100644
--- a/src/node/health_check/health.proto
+++ b/src/node/health_check/health.proto
@@ -32,8 +32,7 @@ syntax = "proto3";
 package grpc.health.v1alpha;
 
 message HealthCheckRequest {
-  string host = 1;
-  string service = 2;
+  string service = 1;
 }
 
 message HealthCheckResponse {
@@ -47,4 +46,4 @@ message HealthCheckResponse {
 
 service Health {
   rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
-}
\ No newline at end of file
+}
diff --git a/src/node/index.js b/src/node/index.js
index b26ab35f2c..889b0ac0e9 100644
--- a/src/node/index.js
+++ b/src/node/index.js
@@ -135,11 +135,21 @@ exports.Server = server.Server;
 exports.status = grpc.status;
 
 /**
+ * Propagate flag name to number mapping
+ */
+exports.propagate = grpc.propagate;
+
+/**
  * Call error name to code number mapping
  */
 exports.callError = grpc.callError;
 
 /**
+ * Write flag name to code number mapping
+ */
+exports.writeFlags = grpc.writeFlags;
+
+/**
  * Credentials factories
  */
 exports.Credentials = grpc.Credentials;
diff --git a/src/node/interop/interop_client.js b/src/node/interop/interop_client.js
index 6d6f9a349e..612dcf01f6 100644
--- a/src/node/interop/interop_client.js
+++ b/src/node/interop/interop_client.js
@@ -264,7 +264,9 @@ function timeoutOnSleepingServer(client, done) {
     payload: {body: zeroBuffer(27182)}
   });
   call.on('error', function(error) {
-    assert.strictEqual(error.code, grpc.status.DEADLINE_EXCEEDED);
+
+    assert(error.code === grpc.status.DEADLINE_EXCEEDED ||
+        error.code === grpc.status.INTERNAL);
     done();
   });
 }
diff --git a/src/node/interop/interop_server.js b/src/node/interop/interop_server.js
index ece22cce31..99155e9958 100644
--- a/src/node/interop/interop_server.js
+++ b/src/node/interop/interop_server.js
@@ -169,8 +169,8 @@ function getServer(port, tls) {
     var key_data = fs.readFileSync(key_path);
     var pem_data = fs.readFileSync(pem_path);
     server_creds = grpc.ServerCredentials.createSsl(null,
-                                                    key_data,
-                                                    pem_data);
+                                                    [{private_key: key_data,
+                                                      cert_chain: pem_data}]);
   } else {
     server_creds = grpc.ServerCredentials.createInsecure();
   }
@@ -194,7 +194,7 @@ if (require.main === module) {
   });
   var server_obj = getServer(argv.port, argv.use_tls === 'true');
   console.log('Server attaching to port ' + argv.port);
-  server_obj.server.listen();
+  server_obj.server.start();
 }
 
 /**
diff --git a/src/node/src/client.js b/src/node/src/client.js
index d14713f393..7b7eae51d2 100644
--- a/src/node/src/client.js
+++ b/src/node/src/client.js
@@ -79,13 +79,19 @@ function ClientWritableStream(call, serialize) {
  * implementation of a method needed for implementing stream.Writable.
  * @access private
  * @param {Buffer} chunk The chunk to write
- * @param {string} encoding Ignored
+ * @param {string} encoding Used to pass write flags
  * @param {function(Error=)} callback Called when the write is complete
  */
 function _write(chunk, encoding, callback) {
   /* jshint validthis: true */
   var batch = {};
-  batch[grpc.opType.SEND_MESSAGE] = this.serialize(chunk);
+  var message = this.serialize(chunk);
+  if (_.isFinite(encoding)) {
+    /* Attach the encoding if it is a finite number. This is the closest we
+     * can get to checking that it is valid flags */
+    message.grpcWriteFlags = encoding;
+  }
+  batch[grpc.opType.SEND_MESSAGE] = message;
   this.call.startBatch(batch, function(err, event) {
     if (err) {
       // Something has gone wrong. Stop writing by failing to call callback
@@ -216,14 +222,19 @@ ClientDuplexStream.prototype.getPeer = getPeer;
 function getCall(channel, method, options) {
   var deadline;
   var host;
+  var parent;
+  var propagate_flags;
   if (options) {
     deadline = options.deadline;
     host = options.host;
+    parent = _.get(options, 'parent.call');
+    propagate_flags = options.propagate_flags;
   }
   if (deadline === undefined) {
     deadline = Infinity;
   }
-  return new grpc.Call(channel, method, deadline, host);
+  return new grpc.Call(channel, method, deadline, host,
+                       parent, propagate_flags);
 }
 
 /**
@@ -268,8 +279,12 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
         return;
       }
       var client_batch = {};
+      var message = serialize(argument);
+      if (options) {
+        message.grpcWriteFlags = options.flags;
+      }
       client_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
-      client_batch[grpc.opType.SEND_MESSAGE] = serialize(argument);
+      client_batch[grpc.opType.SEND_MESSAGE] = message;
       client_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
       client_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
       client_batch[grpc.opType.RECV_MESSAGE] = true;
@@ -402,9 +417,13 @@ function makeServerStreamRequestFunction(method, serialize, deserialize) {
         return;
       }
       var start_batch = {};
+      var message = serialize(argument);
+      if (options) {
+        message.grpcWriteFlags = options.flags;
+      }
       start_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
       start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
-      start_batch[grpc.opType.SEND_MESSAGE] = serialize(argument);
+      start_batch[grpc.opType.SEND_MESSAGE] = message;
       start_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
       call.startBatch(start_batch, function(err, response) {
         if (err) {
diff --git a/src/node/src/server.js b/src/node/src/server.js
index 5c62f5990c..5037abae43 100644
--- a/src/node/src/server.js
+++ b/src/node/src/server.js
@@ -115,8 +115,10 @@ function waitForCancel(call, emitter) {
  * @param {function(*):Buffer=} serialize Serialization function for the
  *     response
  * @param {Object=} metadata Optional trailing metadata to send with status
+ * @param {number=} flags Flags for modifying how the message is sent.
+ *     Defaults to 0.
  */
-function sendUnaryResponse(call, value, serialize, metadata) {
+function sendUnaryResponse(call, value, serialize, metadata, flags) {
   var end_batch = {};
   var status = {
     code: grpc.status.OK,
@@ -130,7 +132,9 @@ function sendUnaryResponse(call, value, serialize, metadata) {
     end_batch[grpc.opType.SEND_INITIAL_METADATA] = {};
     call.metadataSent = true;
   }
-  end_batch[grpc.opType.SEND_MESSAGE] = serialize(value);
+  var message = serialize(value);
+  message.grpcWriteFlags = flags;
+  end_batch[grpc.opType.SEND_MESSAGE] = message;
   end_batch[grpc.opType.SEND_STATUS_FROM_SERVER] = status;
   call.startBatch(end_batch, function (){});
 }
@@ -254,7 +258,7 @@ function ServerWritableStream(call, serialize) {
  * for implementing stream.Writable.
  * @access private
  * @param {Buffer} chunk The chunk of data to write
- * @param {string} encoding Ignored
+ * @param {string} encoding Used to pass write flags
  * @param {function(Error=)} callback Callback to indicate that the write is
  *     complete
  */
@@ -265,7 +269,13 @@ function _write(chunk, encoding, callback) {
     batch[grpc.opType.SEND_INITIAL_METADATA] = {};
     this.call.metadataSent = true;
   }
-  batch[grpc.opType.SEND_MESSAGE] = this.serialize(chunk);
+  var message = this.serialize(chunk);
+  if (_.isFinite(encoding)) {
+    /* Attach the encoding if it is a finite number. This is the closest we
+     * can get to checking that it is valid flags */
+    message.grpcWriteFlags = encoding;
+  }
+  batch[grpc.opType.SEND_MESSAGE] = message;
   this.call.startBatch(batch, function(err, value) {
     if (err) {
       this.emit('error', err);
@@ -432,6 +442,7 @@ function handleUnary(call, handler, metadata) {
   });
   emitter.metadata = metadata;
   waitForCancel(call, emitter);
+  emitter.call = call;
   var batch = {};
   batch[grpc.opType.RECV_MESSAGE] = true;
   call.startBatch(batch, function(err, result) {
@@ -449,14 +460,14 @@ function handleUnary(call, handler, metadata) {
     if (emitter.cancelled) {
       return;
     }
-    handler.func(emitter, function sendUnaryData(err, value, trailer) {
+    handler.func(emitter, function sendUnaryData(err, value, trailer, flags) {
       if (err) {
         if (trailer) {
           err.metadata = trailer;
         }
         handleError(call, err);
       } else {
-        sendUnaryResponse(call, value, handler.serialize, trailer);
+        sendUnaryResponse(call, value, handler.serialize, trailer, flags);
       }
     });
   });
@@ -513,7 +524,7 @@ function handleClientStreaming(call, handler, metadata) {
   });
   waitForCancel(call, stream);
   stream.metadata = metadata;
-  handler.func(stream, function(err, value, trailer) {
+  handler.func(stream, function(err, value, trailer, flags) {
     stream.terminate();
     if (err) {
       if (trailer) {
@@ -521,7 +532,7 @@ function handleClientStreaming(call, handler, metadata) {
       }
       handleError(call, err);
     } else {
-      sendUnaryResponse(call, value, handler.serialize, trailer);
+      sendUnaryResponse(call, value, handler.serialize, trailer, flags);
     }
   });
 }
diff --git a/src/node/test/constant_test.js b/src/node/test/constant_test.js
index 93bf0c8ada..fa06ad4e4d 100644
--- a/src/node/test/constant_test.js
+++ b/src/node/test/constant_test.js
@@ -79,6 +79,18 @@ var callErrorNames = [
 ];
 
 /**
+ * List of all propagate flag names
+ * @const
+ * @type {Array.<string>}
+ */
+var propagateFlagNames = [
+  'DEADLINE',
+  'CENSUS_STATS_CONTEXT',
+  'CENSUS_TRACING_CONTEXT',
+  'CANCELLATION',
+  'DEFAULTS'
+];
+/*
  * List of all connectivity state names
  * @const
  * @type {Array.<string>}
@@ -104,6 +116,12 @@ describe('constants', function() {
              'call error missing: ' + callErrorNames[i]);
     }
   });
+  it('should have all of the propagate flags', function() {
+    for (var i = 0; i < propagateFlagNames.length; i++) {
+      assert(grpc.propagate.hasOwnProperty(propagateFlagNames[i]),
+             'call error missing: ' + propagateFlagNames[i]);
+    }
+  });
   it('should have all of the connectivity states', function() {
     for (var i = 0; i < connectivityStateNames.length; i++) {
       assert(grpc.connectivityState.hasOwnProperty(connectivityStateNames[i]),
diff --git a/src/node/test/health_test.js b/src/node/test/health_test.js
index be4ef1d251..04959f5f55 100644
--- a/src/node/test/health_test.js
+++ b/src/node/test/health_test.js
@@ -41,13 +41,9 @@ var grpc = require('../');
 
 describe('Health Checking', function() {
   var statusMap = {
-    '': {
-      '': 'SERVING',
-      'grpc.test.TestService': 'NOT_SERVING',
-    },
-    virtual_host: {
-      'grpc.test.TestService': 'SERVING'
-    }
+    '': 'SERVING',
+    'grpc.test.TestServiceNotServing': 'NOT_SERVING',
+    'grpc.test.TestServiceServing': 'SERVING'
   };
   var healthServer = new grpc.Server();
   healthServer.addProtoService(health.service,
@@ -71,15 +67,15 @@ describe('Health Checking', function() {
     });
   });
   it('should say that a disabled service is NOT_SERVING', function(done) {
-    healthClient.check({service: 'grpc.test.TestService'},
+    healthClient.check({service: 'grpc.test.TestServiceNotServing'},
                        function(err, response) {
                          assert.ifError(err);
                          assert.strictEqual(response.status, 'NOT_SERVING');
                          done();
                        });
   });
-  it('should say that a service on another host is SERVING', function(done) {
-    healthClient.check({host: 'virtual_host', service: 'grpc.test.TestService'},
+  it('should say that an enabled service is SERVING', function(done) {
+    healthClient.check({service: 'grpc.test.TestServiceServing'},
                        function(err, response) {
                          assert.ifError(err);
                          assert.strictEqual(response.status, 'SERVING');
@@ -93,12 +89,4 @@ describe('Health Checking', function() {
       done();
     });
   });
-  it('should get NOT_FOUND if the host is not registered', function(done) {
-    healthClient.check({host: 'wrong_host', service: 'grpc.test.TestService'},
-                       function(err, response) {
-                         assert(err);
-                         assert.strictEqual(err.code, grpc.status.NOT_FOUND);
-                         done();
-                       });
-  });
 });
diff --git a/src/node/test/server_test.js b/src/node/test/server_test.js
index a9df43909e..78bac8da29 100644
--- a/src/node/test/server_test.js
+++ b/src/node/test/server_test.js
@@ -70,7 +70,9 @@ describe('server', function() {
       var pem_path = path.join(__dirname, '../test/data/server1.pem');
       var key_data = fs.readFileSync(key_path);
       var pem_data = fs.readFileSync(pem_path);
-      var creds = grpc.ServerCredentials.createSsl(null, key_data, pem_data);
+      var creds = grpc.ServerCredentials.createSsl(null,
+                                                   [{private_key: key_data,
+                                                     cert_chain: pem_data}]);
       assert.doesNotThrow(function() {
         port = server.addHttp2Port('0.0.0.0:0', creds);
       });
@@ -83,7 +85,7 @@ describe('server', function() {
       server = new grpc.Server();
     });
   });
-  describe('listen', function() {
+  describe('start', function() {
     var server;
     before(function() {
       server = new grpc.Server();
@@ -92,7 +94,7 @@ describe('server', function() {
     after(function() {
       server.shutdown();
     });
-    it('should listen without error', function() {
+    it('should start without error', function() {
       assert.doesNotThrow(function() {
         server.start();
       });
diff --git a/src/node/test/surface_test.js b/src/node/test/surface_test.js
index 098905e74b..ec7ed87728 100644
--- a/src/node/test/surface_test.js
+++ b/src/node/test/surface_test.js
@@ -67,6 +67,7 @@ function multiDone(done, count) {
     }
   };
 }
+
 var server_insecure_creds = grpc.ServerCredentials.createInsecure();
 
 describe('File loader', function() {
@@ -344,12 +345,14 @@ describe('Echo metadata', function() {
   });
 });
 describe('Other conditions', function() {
+  var test_service;
+  var Client;
   var client;
   var server;
   var port;
   before(function() {
     var test_proto = ProtoBuf.loadProtoFile(__dirname + '/test_service.proto');
-    var test_service = test_proto.lookup('TestService');
+    test_service = test_proto.lookup('TestService');
     server = new grpc.Server();
     server.addProtoService(test_service, {
       unary: function(call, cb) {
@@ -411,7 +414,7 @@ describe('Other conditions', function() {
       }
     });
     port = server.bind('localhost:0', server_insecure_creds);
-    var Client = surface_client.makeProtobufClientConstructor(test_service);
+    Client = surface_client.makeProtobufClientConstructor(test_service);
     client = new Client('localhost:' + port, grpc.Credentials.createInsecure());
     server.start();
   });
@@ -664,6 +667,168 @@ describe('Other conditions', function() {
       });
     });
   });
+  describe('Call propagation', function() {
+    var proxy;
+    var proxy_impl;
+    beforeEach(function() {
+      proxy = new grpc.Server();
+      proxy_impl = {
+        unary: function(call) {},
+        clientStream: function(stream) {},
+        serverStream: function(stream) {},
+        bidiStream: function(stream) {}
+      };
+    });
+    afterEach(function() {
+      console.log('Shutting down server');
+      proxy.shutdown();
+    });
+    describe('Cancellation', function() {
+      it('With a unary call', function(done) {
+        done = multiDone(done, 2);
+        proxy_impl.unary = function(parent, callback) {
+          client.unary(parent.request, function(err, value) {
+            try {
+              assert(err);
+              assert.strictEqual(err.code, grpc.status.CANCELLED);
+            } finally {
+              callback(err, value);
+              done();
+            }
+          }, null, {parent: parent});
+          call.cancel();
+        };
+        proxy.addProtoService(test_service, proxy_impl);
+        var proxy_port = proxy.bind('localhost:0', server_insecure_creds);
+        proxy.start();
+        var proxy_client = new Client('localhost:' + proxy_port,
+                                      grpc.Credentials.createInsecure());
+        var call = proxy_client.unary({}, function(err, value) {
+          done();
+        });
+      });
+      it('With a client stream call', function(done) {
+        done = multiDone(done, 2);
+        proxy_impl.clientStream = function(parent, callback) {
+          client.clientStream(function(err, value) {
+            try {
+              assert(err);
+              assert.strictEqual(err.code, grpc.status.CANCELLED);
+            } finally {
+              callback(err, value);
+              done();
+            }
+          }, null, {parent: parent});
+          call.cancel();
+        };
+        proxy.addProtoService(test_service, proxy_impl);
+        var proxy_port = proxy.bind('localhost:0', server_insecure_creds);
+        proxy.start();
+        var proxy_client = new Client('localhost:' + proxy_port,
+                                      grpc.Credentials.createInsecure());
+        var call = proxy_client.clientStream(function(err, value) {
+          done();
+        });
+      });
+      it('With a server stream call', function(done) {
+        done = multiDone(done, 2);
+        proxy_impl.serverStream = function(parent) {
+          var child = client.serverStream(parent.request, null,
+                                          {parent: parent});
+          child.on('error', function(err) {
+            assert(err);
+            assert.strictEqual(err.code, grpc.status.CANCELLED);
+            done();
+          });
+          call.cancel();
+        };
+        proxy.addProtoService(test_service, proxy_impl);
+        var proxy_port = proxy.bind('localhost:0', server_insecure_creds);
+        proxy.start();
+        var proxy_client = new Client('localhost:' + proxy_port,
+                                      grpc.Credentials.createInsecure());
+        var call = proxy_client.serverStream({});
+        call.on('error', function(err) {
+          done();
+        });
+      });
+      it('With a bidi stream call', function(done) {
+        done = multiDone(done, 2);
+        proxy_impl.bidiStream = function(parent) {
+          var child = client.bidiStream(null, {parent: parent});
+          child.on('error', function(err) {
+            assert(err);
+            assert.strictEqual(err.code, grpc.status.CANCELLED);
+            done();
+          });
+          call.cancel();
+        };
+        proxy.addProtoService(test_service, proxy_impl);
+        var proxy_port = proxy.bind('localhost:0', server_insecure_creds);
+        proxy.start();
+        var proxy_client = new Client('localhost:' + proxy_port,
+                                      grpc.Credentials.createInsecure());
+        var call = proxy_client.bidiStream();
+        call.on('error', function(err) {
+          done();
+        });
+      });
+    });
+    describe('Deadline', function() {
+      /* jshint bitwise:false */
+      var deadline_flags = (grpc.propagate.DEFAULTS &
+          ~grpc.propagate.CANCELLATION);
+      it('With a client stream call', function(done) {
+        done = multiDone(done, 2);
+        proxy_impl.clientStream = function(parent, callback) {
+          client.clientStream(function(err, value) {
+            try {
+              assert(err);
+              assert(err.code === grpc.status.DEADLINE_EXCEEDED ||
+                  err.code === grpc.status.INTERNAL);
+            } finally {
+              callback(err, value);
+              done();
+            }
+          }, null, {parent: parent, propagate_flags: deadline_flags});
+        };
+        proxy.addProtoService(test_service, proxy_impl);
+        var proxy_port = proxy.bind('localhost:0', server_insecure_creds);
+        proxy.start();
+        var proxy_client = new Client('localhost:' + proxy_port,
+                                      grpc.Credentials.createInsecure());
+        var deadline = new Date();
+        deadline.setSeconds(deadline.getSeconds() + 1);
+        proxy_client.clientStream(function(err, value) {
+          done();
+        }, null, {deadline: deadline});
+      });
+      it('With a bidi stream call', function(done) {
+        done = multiDone(done, 2);
+        proxy_impl.bidiStream = function(parent) {
+          var child = client.bidiStream(
+              null, {parent: parent, propagate_flags: deadline_flags});
+          child.on('error', function(err) {
+            assert(err);
+            assert(err.code === grpc.status.DEADLINE_EXCEEDED ||
+                err.code === grpc.status.INTERNAL);
+            done();
+          });
+        };
+        proxy.addProtoService(test_service, proxy_impl);
+        var proxy_port = proxy.bind('localhost:0', server_insecure_creds);
+        proxy.start();
+        var proxy_client = new Client('localhost:' + proxy_port,
+                                      grpc.Credentials.createInsecure());
+        var deadline = new Date();
+        deadline.setSeconds(deadline.getSeconds() + 1);
+        var call = proxy_client.bidiStream(null, {deadline: deadline});
+        call.on('error', function(err) {
+          done();
+        });
+      });
+    });
+  });
 });
 describe('Cancelling surface client', function() {
   var client;
diff --git a/src/objective-c/tests/GRPCClientTests.m b/src/objective-c/tests/GRPCClientTests.m
index 06581e7599..09a55e0704 100644
--- a/src/objective-c/tests/GRPCClientTests.m
+++ b/src/objective-c/tests/GRPCClientTests.m
@@ -53,6 +53,37 @@ static ProtoMethod *kInexistentMethod;
 static ProtoMethod *kEmptyCallMethod;
 static ProtoMethod *kUnaryCallMethod;
 
+// This is an observer class for testing that responseMetadata is KVO-compliant
+
+@interface PassthroughObserver : NSObject
+
+- (instancetype) initWithCallback:(void (^)(NSString*, id, NSDictionary*))callback;
+
+- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change
+                       context:(void *)context;
+@end
+
+@implementation PassthroughObserver {
+  void (^_callback)(NSString*, id, NSDictionary*);
+}
+
+- (instancetype)initWithCallback:(void (^)(NSString *, id, NSDictionary *))callback {
+  self = [super init];
+  if (self) {
+    _callback = callback;
+  }
+  return self;
+  
+}
+
+- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
+{
+  _callback(keyPath, object, change);
+  [object removeObserver:self forKeyPath:keyPath];
+}
+
+@end
+
 @interface GRPCClientTests : XCTestCase
 @end
 
@@ -183,4 +214,35 @@ static ProtoMethod *kUnaryCallMethod;
   [self waitForExpectationsWithTimeout:4 handler:nil];
 }
 
+- (void)testResponseMetadataKVO {
+  __weak XCTestExpectation *response = [self expectationWithDescription:@"Empty response received."];
+  __weak XCTestExpectation *completion = [self expectationWithDescription:@"Empty RPC completed."];
+  __weak XCTestExpectation *metadata = [self expectationWithDescription:@"Metadata changed."];
+  
+  GRPCCall *call = [[GRPCCall alloc] initWithHost:kHostAddress
+                                             path:kEmptyCallMethod.HTTPPath
+                                   requestsWriter:[GRXWriter writerWithValue:[NSData data]]];
+  
+  PassthroughObserver *observer = [[PassthroughObserver alloc] initWithCallback:^(NSString *keypath, id object, NSDictionary * change) {
+    if ([keypath isEqual: @"responseHeaders"]) {
+      [metadata fulfill];
+    }
+  }];
+  
+  [call addObserver:observer forKeyPath:@"responseHeaders" options:0 context:NULL];
+  
+  id<GRXWriteable> responsesWriteable = [[GRXWriteable alloc] initWithValueHandler:^(NSData *value) {
+    XCTAssertNotNil(value, @"nil value received as response.");
+    XCTAssertEqual([value length], 0, @"Non-empty response received: %@", value);
+    [response fulfill];
+  } completionHandler:^(NSError *errorOrNil) {
+    XCTAssertNil(errorOrNil, @"Finished with unexpected error: %@", errorOrNil);
+    [completion fulfill];
+  }];
+  
+  [call startWithWriteable:responsesWriteable];
+  
+  [self waitForExpectationsWithTimeout:8 handler:nil];
+}
+
 @end
diff --git a/src/php/README.md b/src/php/README.md
index 1804606e09..f432935fde 100644
--- a/src/php/README.md
+++ b/src/php/README.md
@@ -7,17 +7,17 @@ This directory contains source code for PHP implementation of gRPC layered on sh
 
 Alpha : Ready for early adopters
 
-## ENVIRONMENT
+## Environment
 
 Prerequisite: PHP 5.5 or later, `phpunit`, `pecl`
 
-Linux:
+**Linux:**
 
 ```sh
 $ sudo apt-get install php5 php5-dev phpunit php-pear
 ```
 
-OS X:
+**Mac OS X:**
 
 ```sh
 $ curl https://phar.phpunit.de/phpunit.phar -o phpunit.phar
@@ -28,10 +28,39 @@ $ curl -O http://pear.php.net/go-pear.phar
 $ sudo php -d detect_unicode=0 go-pear.phar
 ```
 
-## Build from Homebrew
+## Quick Install
 
-On Mac OS X, install [homebrew][]. On Linux, install [linuxbrew][]. Run the following command to
-install gRPC.
+**Linux (Debian):**
+
+Add [Debian unstable][] to your `sources.list` file. Example:
+
+```sh
+echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+sudo tee -a /etc/apt/sources.list
+```
+
+Install the gRPC Debian package
+
+```sh
+sudo apt-get update
+sudo apt-get install libgrpc-dev
+```
+
+Install the gRPC PHP extension
+
+```sh
+sudo pecl install grpc-alpha
+```
+
+**Mac OS X:**
+
+Install [homebrew][]. Example:
+
+```sh
+ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
+```
+
+Install the gRPC core library and the PHP extension in one step
 
 ```sh
 $ curl -fsSL https://goo.gl/getgrpc | bash -s php
@@ -39,6 +68,7 @@ $ curl -fsSL https://goo.gl/getgrpc | bash -s php
 
 This will download and run the [gRPC install script][] and compile the gRPC PHP extension.
 
+
 ## Build from Source
 
 Clone this repository
@@ -71,7 +101,7 @@ $ sudo make install
 Install the gRPC PHP extension
 
 ```sh
-$ sudo pecl install grpc
+$ sudo pecl install grpc-alpha
 ```
 
 OR
@@ -140,6 +170,6 @@ $ ./bin/run_gen_code_test.sh
 ```
 
 [homebrew]:http://brew.sh
-[linuxbrew]:https://github.com/Homebrew/linuxbrew#installation
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
 [Node]:https://github.com/grpc/grpc/tree/master/src/node/examples
+[Debian unstable]:https://www.debian.org/releases/sid/
diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index 1cf766c312..252623d0c3 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -216,13 +216,18 @@ PHP_METHOD(Call, __construct) {
   char *method;
   int method_len;
   zval *deadline_obj;
-  /* "OsO" == 1 Object, 1 string, 1 Object */
-  if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "OsO", &channel_obj,
-                            grpc_ce_channel, &method, &method_len,
-                            &deadline_obj, grpc_ce_timeval) == FAILURE) {
+  char *host_override = NULL;
+  int host_override_len = 0;
+  /* "OsO|s" == 1 Object, 1 string, 1 Object, 1 optional string */
+  if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "OsO|s",
+                            &channel_obj, grpc_ce_channel,
+                            &method, &method_len,
+                            &deadline_obj, grpc_ce_timeval,
+                            &host_override, &host_override_len)
+      == FAILURE) {
     zend_throw_exception(
         spl_ce_InvalidArgumentException,
-        "Call expects a Channel, a String, and a Timeval",
+        "Call expects a Channel, a String, a Timeval and an optional String",
         1 TSRMLS_CC);
     return;
   }
@@ -241,7 +246,7 @@ PHP_METHOD(Call, __construct) {
           deadline_obj TSRMLS_CC);
   call->wrapped = grpc_channel_create_call(
       channel->wrapped, NULL, GRPC_PROPAGATE_DEFAULTS, completion_queue, method,
-      channel->target, deadline->wrapped, NULL);
+      host_override, deadline->wrapped, NULL);
 }
 
 /**
@@ -273,7 +278,6 @@ PHP_METHOD(Call, startBatch) {
   grpc_byte_buffer *message;
   int cancelled;
   grpc_call_error error;
-  grpc_event event;
   zval *result;
   char *message_str;
   size_t message_len;
@@ -398,6 +402,7 @@ PHP_METHOD(Call, startBatch) {
     }
     ops[op_num].op = (grpc_op_type)index;
     ops[op_num].flags = 0;
+    ops[op_num].reserved = NULL;
     op_num++;
   }
   error = grpc_call_start_batch(call->wrapped, ops, op_num, call->wrapped,
@@ -408,14 +413,8 @@ PHP_METHOD(Call, startBatch) {
                          (long)error TSRMLS_CC);
     goto cleanup;
   }
-  event = grpc_completion_queue_pluck(completion_queue, call->wrapped,
-                                      gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
-  if (!event.success) {
-    zend_throw_exception(spl_ce_LogicException,
-                         "The batch failed for some reason",
-                         1 TSRMLS_CC);
-    goto cleanup;
-  }
+  grpc_completion_queue_pluck(completion_queue, call->wrapped,
+                              gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
   for (int i = 0; i < op_num; i++) {
     switch(ops[i].op) {
       case GRPC_OP_SEND_INITIAL_METADATA:
diff --git a/src/php/ext/grpc/channel.c b/src/php/ext/grpc/channel.c
index f8ce04d902..7a981675de 100644
--- a/src/php/ext/grpc/channel.c
+++ b/src/php/ext/grpc/channel.c
@@ -64,7 +64,6 @@ void free_wrapped_grpc_channel(void *object TSRMLS_DC) {
   if (channel->wrapped != NULL) {
     grpc_channel_destroy(channel->wrapped);
   }
-  efree(channel->target);
   efree(channel);
 }
 
@@ -141,9 +140,6 @@ PHP_METHOD(Channel, __construct) {
   HashTable *array_hash;
   zval **creds_obj = NULL;
   wrapped_grpc_credentials *creds = NULL;
-  zval **override_obj;
-  char *override;
-  int override_len;
   /* "s|a" == 1 string, 1 optional array */
   if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|a", &target,
                             &target_length, &args_array) == FAILURE) {
@@ -151,8 +147,6 @@ PHP_METHOD(Channel, __construct) {
                          "Channel expects a string and an array", 1 TSRMLS_CC);
     return;
   }
-  override = target;
-  override_len = target_length;
   if (args_array == NULL) {
     channel->wrapped = grpc_insecure_channel_create(target, NULL, NULL);
   } else {
@@ -169,19 +163,6 @@ PHP_METHOD(Channel, __construct) {
           *creds_obj TSRMLS_CC);
       zend_hash_del(array_hash, "credentials", 12);
     }
-    if (zend_hash_find(array_hash, GRPC_SSL_TARGET_NAME_OVERRIDE_ARG,
-                       sizeof(GRPC_SSL_TARGET_NAME_OVERRIDE_ARG),
-                       (void **)&override_obj) == SUCCESS) {
-      if (Z_TYPE_PP(override_obj) != IS_STRING) {
-        zend_throw_exception(spl_ce_InvalidArgumentException,
-                             GRPC_SSL_TARGET_NAME_OVERRIDE_ARG
-                             " must be a string",
-                             1 TSRMLS_CC);
-        return;
-      }
-      override = Z_STRVAL_PP(override_obj);
-      override_len = Z_STRLEN_PP(override_obj);
-    }
     php_grpc_read_args_array(args_array, &args);
     if (creds == NULL) {
       channel->wrapped = grpc_insecure_channel_create(target, &args, NULL);
@@ -192,8 +173,6 @@ PHP_METHOD(Channel, __construct) {
     }
     efree(args.args);
   }
-  channel->target = ecalloc(override_len + 1, sizeof(char));
-  memcpy(channel->target, override, override_len);
 }
 
 /**
diff --git a/src/php/ext/grpc/channel.h b/src/php/ext/grpc/channel.h
index c13fa4c6d7..78a16ed0c9 100755
--- a/src/php/ext/grpc/channel.h
+++ b/src/php/ext/grpc/channel.h
@@ -53,7 +53,6 @@ typedef struct wrapped_grpc_channel {
   zend_object std;
 
   grpc_channel *wrapped;
-  char *target;
 } wrapped_grpc_channel;
 
 /* Initializes the Channel class */
diff --git a/src/php/lib/Grpc/BaseStub.php b/src/php/lib/Grpc/BaseStub.php
index 9d6a77b855..2e980c5eed 100755
--- a/src/php/lib/Grpc/BaseStub.php
+++ b/src/php/lib/Grpc/BaseStub.php
@@ -110,10 +110,10 @@ class BaseStub {
   }
 
   private function _checkConnectivityState($new_state) {
-    if ($new_state == Grpc\CHANNEL_READY) {
+    if ($new_state == \Grpc\CHANNEL_READY) {
       return true;
     }
-    if ($new_state == Grpc\CHANNEL_FATAL_ERROR) {
+    if ($new_state == \Grpc\CHANNEL_FATAL_FAILURE) {
       throw new Exception('Failed to connect to server');
     }
     return false;
diff --git a/src/php/tests/generated_code/AbstractGeneratedCodeTest.php b/src/php/tests/generated_code/AbstractGeneratedCodeTest.php
index 8b7e67f57c..287621d930 100644
--- a/src/php/tests/generated_code/AbstractGeneratedCodeTest.php
+++ b/src/php/tests/generated_code/AbstractGeneratedCodeTest.php
@@ -39,6 +39,14 @@ abstract class AbstractGeneratedCodeTest extends PHPUnit_Framework_TestCase {
   protected static $client;
   protected static $timeout;
 
+  public function testWaitForNotReady() {
+    $this->assertFalse(self::$client->waitForReady(1));
+  }
+
+  public function testWaitForReady() {
+    $this->assertTrue(self::$client->waitForReady(250000));
+  }
+
   public function testSimpleRequest() {
     $div_arg = new math\DivArgs();
     $div_arg->setDividend(7);
diff --git a/src/php/tests/generated_code/GeneratedCodeTest.php b/src/php/tests/generated_code/GeneratedCodeTest.php
index 1e4742fc80..a1a2ce81db 100755
--- a/src/php/tests/generated_code/GeneratedCodeTest.php
+++ b/src/php/tests/generated_code/GeneratedCodeTest.php
@@ -35,7 +35,7 @@ require 'AbstractGeneratedCodeTest.php';
 
 class GeneratedCodeTest extends AbstractGeneratedCodeTest {
   public static function setUpBeforeClass() {
-    self::$client = new math\MathClient(new Grpc\BaseStub(
-        getenv('GRPC_TEST_HOST'), []));
+    self::$client = new math\MathClient(
+        getenv('GRPC_TEST_HOST'), []);
   }
 }
diff --git a/src/php/tests/generated_code/GeneratedCodeWithCallbackTest.php b/src/php/tests/generated_code/GeneratedCodeWithCallbackTest.php
index f8ec1e7da8..68f57d34ad 100644
--- a/src/php/tests/generated_code/GeneratedCodeWithCallbackTest.php
+++ b/src/php/tests/generated_code/GeneratedCodeWithCallbackTest.php
@@ -35,13 +35,13 @@ require 'AbstractGeneratedCodeTest.php';
 
 class GeneratedCodeWithCallbackTest extends AbstractGeneratedCodeTest {
   public static function setUpBeforeClass() {
-    self::$client = new math\MathClient(new Grpc\BaseStub(
+    self::$client = new math\MathClient(
         getenv('GRPC_TEST_HOST'), ['update_metadata' =>
                                    function($a_hash,
                                             $client = array()) {
                                      $a_copy = $a_hash;
                                      $a_copy['foo'] = ['bar'];
                                      return $a_copy;
-                                   }]));
+                                   }]);
   }
 }
diff --git a/src/php/tests/interop/interop_client.php b/src/php/tests/interop/interop_client.php
index 44e6242c29..376d306da0 100755
--- a/src/php/tests/interop/interop_client.php
+++ b/src/php/tests/interop/interop_client.php
@@ -271,7 +271,7 @@ function cancelAfterFirstResponse($stub) {
 }
 
 function timeoutOnSleepingServer($stub) {
-  $call = $stub->FullDuplexCall(array('timeout' => 500000));
+  $call = $stub->FullDuplexCall(array('timeout' => 1000));
   $request = new grpc\testing\StreamingOutputCallRequest();
   $request->setResponseType(grpc\testing\PayloadType::COMPRESSABLE);
   $response_parameters = new grpc\testing\ResponseParameters();
diff --git a/src/php/tests/unit_tests/SecureEndToEndTest.php b/src/php/tests/unit_tests/SecureEndToEndTest.php
index f91c006da5..60341b983d 100755
--- a/src/php/tests/unit_tests/SecureEndToEndTest.php
+++ b/src/php/tests/unit_tests/SecureEndToEndTest.php
@@ -40,13 +40,15 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase{
         file_get_contents(dirname(__FILE__) . '/../data/server1.key'),
         file_get_contents(dirname(__FILE__) . '/../data/server1.pem'));
     $this->server = new Grpc\Server();
-    $port = $this->server->addSecureHttp2Port('0.0.0.0:0',
+    $this->port = $this->server->addSecureHttp2Port('0.0.0.0:0',
                                               $server_credentials);
     $this->server->start();
+    $this->host_override = 'foo.test.google.fr';
     $this->channel = new Grpc\Channel(
-        'localhost:' . $port,
+        'localhost:' . $this->port,
         [
-            'grpc.ssl_target_name_override' => 'foo.test.google.fr',
+            'grpc.ssl_target_name_override' => $this->host_override,
+            'grpc.default_authority' => $this->host_override,
             'credentials' => $credentials
          ]);
   }
@@ -61,7 +63,8 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase{
     $status_text = 'xyz';
     $call = new Grpc\Call($this->channel,
                           'dummy_method',
-                          $deadline);
+                          $deadline,
+                          $this->host_override);
 
     $event = $call->startBatch([
         Grpc\OP_SEND_INITIAL_METADATA => [],
@@ -112,7 +115,8 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase{
 
     $call = new Grpc\Call($this->channel,
                           'dummy_method',
-                          $deadline);
+                          $deadline,
+                          $this->host_override);
 
     $event = $call->startBatch([
         Grpc\OP_SEND_INITIAL_METADATA => [],
diff --git a/src/python/README.md b/src/python/README.md
index 2beb3a913a..de0142db05 100644
--- a/src/python/README.md
+++ b/src/python/README.md
@@ -9,12 +9,36 @@ Alpha : Ready for early adopters
 PREREQUISITES
 -------------
 - Python 2.7, virtualenv, pip
-- [homebrew][] on Mac OS X, [linuxbrew][] on Linux.  These simplify the installation of the gRPC C core.
+- [homebrew][] on Mac OS X.  These simplify the installation of the gRPC C core.
 
 INSTALLATION
 -------------
-On Mac OS X, install [homebrew][]. On Linux, install [linuxbrew][].
-Run the following command to install gRPC Python.
+
+**Linux (Debian):**
+
+Add [Debian unstable][] to your `sources.list` file. Example:
+
+```sh
+echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+sudo tee -a /etc/apt/sources.list
+```
+
+Install the gRPC Debian package
+
+```sh
+sudo apt-get update
+sudo apt-get install libgrpc-dev
+```
+
+Install the gRPC Python module
+
+```sh
+sudo pip install grpcio
+```
+
+**Mac OS X**
+
+Install [homebrew][]. Run the following command to install gRPC Python.
 ```sh
 $ curl -fsSL https://goo.gl/getgrpc | bash -s python
 ```
@@ -27,11 +51,6 @@ Please read our online documentation for a [Quick Start][] and a [detailed examp
 BUILDING FROM SOURCE
 ---------------------
 - Clone this repository
-- Build the gRPC core from the root of the
-  [gRPC Git repository](https://github.com/grpc/grpc)
-```
-$ make shared_c static_c
-```
 
 - Use build_python.sh to build the Python code and install it into a virtual environment
 ```
@@ -60,7 +79,7 @@ $ ../../tools/distrib/python/submit.py
 ```
 
 [homebrew]:http://brew.sh
-[linuxbrew]:https://github.com/Homebrew/linuxbrew#installation
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
 [Quick Start]:http://www.grpc.io/docs/tutorials/basic/python.html
 [detailed example]:http://www.grpc.io/docs/installation/python.html
+[Debian unstable]:https://www.debian.org/releases/sid/
diff --git a/src/python/grpcio/README.rst b/src/python/grpcio/README.rst
index 00bdecf56f..c7b5a3bde4 100644
--- a/src/python/grpcio/README.rst
+++ b/src/python/grpcio/README.rst
@@ -6,7 +6,7 @@ Package for GRPC Python.
 Dependencies
 ------------
 
-Ensure you have installed the gRPC core.  On Mac OS X, install homebrew_. On Linux, install linuxbrew_.
+Ensure you have installed the gRPC core.  On Mac OS X, install homebrew_.
 Run the following command to install gRPC Python.
 
 ::
@@ -19,5 +19,4 @@ Otherwise, `install from source`_
 
 .. _`install from source`: https://github.com/grpc/grpc/blob/master/src/python/README.md#building-from-source
 .. _homebrew: http://brew.sh
-.. _linuxbrew: https://github.com/Homebrew/linuxbrew#installation
 .. _`gRPC install script`: https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
diff --git a/src/python/grpcio/grpc/_adapter/_c/types.h b/src/python/grpcio/grpc/_adapter/_c/types.h
index f646465c63..f6ff957baa 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types.h
+++ b/src/python/grpcio/grpc/_adapter/_c/types.h
@@ -146,6 +146,7 @@ typedef struct Server {
   PyObject_HEAD
   grpc_server *c_serv;
   CompletionQueue *cq;
+  int shutdown_called;
 } Server;
 Server *pygrpc_Server_new(PyTypeObject *type, PyObject *args, PyObject *kwargs);
 void pygrpc_Server_dealloc(Server *self);
@@ -156,6 +157,7 @@ PyObject *pygrpc_Server_add_http2_port(
 PyObject *pygrpc_Server_start(Server *self, PyObject *ignored);
 PyObject *pygrpc_Server_shutdown(
     Server *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Server_cancel_all_calls(Server *self, PyObject *unused);
 extern PyTypeObject pygrpc_Server_type;
 
 /*=========*/
diff --git a/src/python/grpcio/grpc/_adapter/_c/types/server.c b/src/python/grpcio/grpc/_adapter/_c/types/server.c
index 15c98f28eb..8feab8aab1 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types/server.c
+++ b/src/python/grpcio/grpc/_adapter/_c/types/server.c
@@ -45,6 +45,8 @@ PyMethodDef pygrpc_Server_methods[] = {
      METH_KEYWORDS, ""},
     {"start", (PyCFunction)pygrpc_Server_start, METH_NOARGS, ""},
     {"shutdown", (PyCFunction)pygrpc_Server_shutdown, METH_KEYWORDS, ""},
+    {"cancel_all_calls", (PyCFunction)pygrpc_Server_cancel_all_calls,
+     METH_NOARGS, ""},
     {NULL}
 };
 const char pygrpc_Server_doc[] = "See grpc._adapter._types.Server.";
@@ -109,6 +111,7 @@ Server *pygrpc_Server_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
   pygrpc_discard_channel_args(c_args);
   self->cq = cq;
   Py_INCREF(self->cq);
+  self->shutdown_called = 0;
   return self;
 }
 
@@ -163,6 +166,7 @@ PyObject *pygrpc_Server_add_http2_port(
 
 PyObject *pygrpc_Server_start(Server *self, PyObject *ignored) {
   grpc_server_start(self->c_serv);
+  self->shutdown_called = 0;
   Py_RETURN_NONE;
 }
 
@@ -176,5 +180,17 @@ PyObject *pygrpc_Server_shutdown(
   }
   tag = pygrpc_produce_server_shutdown_tag(user_tag);
   grpc_server_shutdown_and_notify(self->c_serv, self->cq->c_cq, tag);
+  self->shutdown_called = 1;
+  Py_RETURN_NONE;
+}
+
+PyObject *pygrpc_Server_cancel_all_calls(Server *self, PyObject *unused) {
+  if (!self->shutdown_called) {
+    PyErr_SetString(
+        PyExc_RuntimeError,
+        "shutdown must have been called prior to calling cancel_all_calls!");
+    return NULL;
+  }
+  grpc_server_cancel_all_calls(self->c_serv);
   Py_RETURN_NONE;
 }
diff --git a/src/python/grpcio/grpc/_adapter/_c/utility.c b/src/python/grpcio/grpc/_adapter/_c/utility.c
index 2eea0e18ef..590f7e013a 100644
--- a/src/python/grpcio/grpc/_adapter/_c/utility.c
+++ b/src/python/grpcio/grpc/_adapter/_c/utility.c
@@ -184,6 +184,7 @@ int pygrpc_produce_op(PyObject *op, grpc_op *result) {
     return 0;
   }
   c_op.op = type;
+  c_op.reserved = NULL;
   c_op.flags = PyInt_AsLong(PyTuple_GET_ITEM(op, WRITE_FLAGS_INDEX));
   if (PyErr_Occurred()) {
     return 0;
diff --git a/src/python/grpcio/grpc/_adapter/_low.py b/src/python/grpcio/grpc/_adapter/_low.py
index 147086e725..3859ebb0e2 100644
--- a/src/python/grpcio/grpc/_adapter/_low.py
+++ b/src/python/grpcio/grpc/_adapter/_low.py
@@ -124,3 +124,6 @@ class Server(_types.Server):
 
   def request_call(self, completion_queue, tag):
     return self.server.request_call(completion_queue.completion_queue, tag)
+
+  def cancel_all_calls(self):
+    return self.server.cancel_all_calls()
diff --git a/src/python/grpcio/grpc/_links/invocation.py b/src/python/grpcio/grpc/_links/invocation.py
index 0058ae91f8..ee3d72fdbc 100644
--- a/src/python/grpcio/grpc/_links/invocation.py
+++ b/src/python/grpcio/grpc/_links/invocation.py
@@ -101,7 +101,7 @@ class _Kernel(object):
     else:
       ticket = links.Ticket(
           operation_id, rpc_state.sequence_number, None, None, None, None, 1,
-          None, None, None, None, None, None)
+          None, None, None, None, None, None, None)
       rpc_state.sequence_number += 1
       self._relay.add_value(ticket)
       rpc_state.low_write = _LowWrite.OPEN
@@ -118,7 +118,7 @@ class _Kernel(object):
       ticket = links.Ticket(
           operation_id, rpc_state.sequence_number, None, None, None, None, None,
           None, rpc_state.response_deserializer(event.bytes), None, None, None,
-          None)
+          None, None)
       rpc_state.sequence_number += 1
       self._relay.add_value(ticket)
 
@@ -129,7 +129,7 @@ class _Kernel(object):
     ticket = links.Ticket(
         operation_id, rpc_state.sequence_number, None, None,
         links.Ticket.Subscription.FULL, None, None, event.metadata, None, None,
-        None, None, None)
+        None, None, None, None)
     rpc_state.sequence_number += 1
     self._relay.add_value(ticket)
 
@@ -141,12 +141,14 @@ class _Kernel(object):
       termination = links.Ticket.Termination.CANCELLATION
     elif event.status.code is _intermediary_low.Code.DEADLINE_EXCEEDED:
       termination = links.Ticket.Termination.EXPIRATION
+    elif event.status.code is _intermediary_low.Code.UNKNOWN:
+      termination = links.Ticket.Termination.LOCAL_FAILURE
     else:
       termination = links.Ticket.Termination.TRANSMISSION_FAILURE
     ticket = links.Ticket(
         operation_id, rpc_state.sequence_number, None, None, None, None, None,
         None, None, event.metadata, event.status.code, event.status.details,
-        termination)
+        termination, None)
     rpc_state.sequence_number += 1
     self._relay.add_value(ticket)
 
@@ -349,7 +351,7 @@ def invocation_link(channel, host, request_serializers, response_deserializers):
   """Creates an InvocationLink.
 
   Args:
-    channel: A channel for use by the link.
+    channel: An _intermediary_low.Channel for use by the link.
     host: The host to specify when invoking RPCs.
     request_serializers: A dict from group-method pair to request object
       serialization behavior.
diff --git a/src/python/grpcio/grpc/_links/service.py b/src/python/grpcio/grpc/_links/service.py
index 5c636d61ab..43c4c0e80c 100644
--- a/src/python/grpcio/grpc/_links/service.py
+++ b/src/python/grpcio/grpc/_links/service.py
@@ -40,6 +40,19 @@ from grpc.framework.foundation import logging_pool
 from grpc.framework.foundation import relay
 from grpc.framework.interfaces.links import links
 
+_TERMINATION_KIND_TO_CODE = {
+    links.Ticket.Termination.COMPLETION: _intermediary_low.Code.OK,
+    links.Ticket.Termination.CANCELLATION: _intermediary_low.Code.CANCELLED,
+    links.Ticket.Termination.EXPIRATION:
+        _intermediary_low.Code.DEADLINE_EXCEEDED,
+    links.Ticket.Termination.SHUTDOWN: _intermediary_low.Code.UNAVAILABLE,
+    links.Ticket.Termination.RECEPTION_FAILURE: _intermediary_low.Code.INTERNAL,
+    links.Ticket.Termination.TRANSMISSION_FAILURE:
+        _intermediary_low.Code.INTERNAL,
+    links.Ticket.Termination.LOCAL_FAILURE: _intermediary_low.Code.UNKNOWN,
+    links.Ticket.Termination.REMOTE_FAILURE: _intermediary_low.Code.UNKNOWN,
+}
+
 
 @enum.unique
 class _Read(enum.Enum):
@@ -93,6 +106,15 @@ def _metadatafy(call, metadata):
     call.add_metadata(metadata_key, metadata_value)
 
 
+def _status(termination_kind, code, details):
+  effective_details = b'' if details is None else details
+  if code is None:
+    effective_code = _TERMINATION_KIND_TO_CODE[termination_kind]
+  else:
+    effective_code = code
+  return _intermediary_low.Status(effective_code, effective_details)
+
+
 class _Kernel(object):
 
   def __init__(self, request_deserializers, response_serializers, ticket_relay):
@@ -131,7 +153,7 @@ class _Kernel(object):
     ticket = links.Ticket(
         call, 0, group, method, links.Ticket.Subscription.FULL,
         service_acceptance.deadline - time.time(), None, event.metadata, None,
-        None, None, None, None)
+        None, None, None, None, 'TODO: Service Context Object!')
     self._relay.add_value(ticket)
 
   def _on_read_event(self, event):
@@ -157,7 +179,7 @@ class _Kernel(object):
         # rpc_state.read = _Read.AWAITING_ALLOWANCE
     ticket = links.Ticket(
         call, rpc_state.sequence_number, None, None, None, None, None, None,
-        payload, None, None, None, termination)
+        payload, None, None, None, termination, None)
     rpc_state.sequence_number += 1
     self._relay.add_value(ticket)
 
@@ -170,13 +192,15 @@ class _Kernel(object):
     if rpc_state.high_write is _HighWrite.CLOSED:
       if rpc_state.terminal_metadata is not None:
         _metadatafy(call, rpc_state.terminal_metadata)
-      call.status(
-          _intermediary_low.Status(rpc_state.code, rpc_state.message), call)
+      status = _status(
+          links.Ticket.Termination.COMPLETION, rpc_state.code,
+          rpc_state.message)
+      call.status(status, call)
       rpc_state.low_write = _LowWrite.CLOSED
     else:
       ticket = links.Ticket(
           call, rpc_state.sequence_number, None, None, None, None, 1, None,
-          None, None, None, None, None)
+          None, None, None, None, None, None)
       rpc_state.sequence_number += 1
       self._relay.add_value(ticket)
       rpc_state.low_write = _LowWrite.OPEN
@@ -198,7 +222,7 @@ class _Kernel(object):
       termination = links.Ticket.Termination.TRANSMISSION_FAILURE
     ticket = links.Ticket(
         call, rpc_state.sequence_number, None, None, None, None, None, None,
-        None, None, None, None, termination)
+        None, None, None, None, termination, None)
     rpc_state.sequence_number += 1
     self._relay.add_value(ticket)
 
@@ -239,7 +263,7 @@ class _Kernel(object):
       elif not rpc_state.premetadataed:
         if (ticket.terminal_metadata is not None or
             ticket.payload is not None or
-            ticket.termination is links.Ticket.Termination.COMPLETION or
+            ticket.termination is not None or
             ticket.code is not None or
             ticket.message is not None):
           call.premetadata()
@@ -257,11 +281,11 @@ class _Kernel(object):
             termination = None
           else:
             termination = links.Ticket.Termination.COMPLETION
-          ticket = links.Ticket(
+          early_read_ticket = links.Ticket(
               call, rpc_state.sequence_number, None, None, None, None, None,
-              None, payload, None, None, None, termination)
+              None, payload, None, None, None, termination, None)
           rpc_state.sequence_number += 1
-          self._relay.add_value(ticket)
+          self._relay.add_value(early_read_ticket)
 
       if ticket.payload is not None:
         call.write(rpc_state.response_serializer(ticket.payload), call)
@@ -279,14 +303,17 @@ class _Kernel(object):
         if rpc_state.low_write is _LowWrite.OPEN:
           if rpc_state.terminal_metadata is not None:
             _metadatafy(call, rpc_state.terminal_metadata)
-          status = _intermediary_low.Status(
-              _intermediary_low.Code.OK
-              if rpc_state.code is None else rpc_state.code,
-              '' if rpc_state.message is None else rpc_state.message)
+          status = _status(
+              links.Ticket.Termination.COMPLETION, rpc_state.code,
+              rpc_state.message)
           call.status(status, call)
           rpc_state.low_write = _LowWrite.CLOSED
       elif ticket.termination is not None:
-        call.cancel()
+        if rpc_state.terminal_metadata is not None:
+          _metadatafy(call, rpc_state.terminal_metadata)
+        status = _status(
+            ticket.termination, rpc_state.code, rpc_state.message)
+        call.status(status, call)
         self._rpc_states.pop(call, None)
 
   def add_port(self, port, server_credentials):
diff --git a/src/python/grpcio/grpc/early_adopter/implementations.py b/src/python/grpcio/grpc/early_adopter/implementations.py
index 10919fae69..9c396aa7ad 100644
--- a/src/python/grpcio/grpc/early_adopter/implementations.py
+++ b/src/python/grpcio/grpc/early_adopter/implementations.py
@@ -41,13 +41,15 @@ from grpc.framework.base import util as _base_utilities
 from grpc.framework.face import implementations as _face_implementations
 from grpc.framework.foundation import logging_pool
 
-_THREAD_POOL_SIZE = 8
+_DEFAULT_THREAD_POOL_SIZE = 8
 _ONE_DAY_IN_SECONDS = 24 * 60 * 60
 
 
 class _Server(interfaces.Server):
 
-  def __init__(self, breakdown, port, private_key, certificate_chain):
+  def __init__(
+        self, breakdown, port, private_key, certificate_chain,
+        thread_pool_size=_DEFAULT_THREAD_POOL_SIZE):
     self._lock = threading.Lock()
     self._breakdown = breakdown
     self._port = port
@@ -56,6 +58,7 @@ class _Server(interfaces.Server):
     else:
       self._key_chain_pairs = ((private_key, certificate_chain),)
 
+    self._pool_size = thread_pool_size
     self._pool = None
     self._back = None
     self._fore_link = None
@@ -63,7 +66,7 @@ class _Server(interfaces.Server):
   def _start(self):
     with self._lock:
       if self._pool is None:
-        self._pool = logging_pool.pool(_THREAD_POOL_SIZE)
+        self._pool = logging_pool.pool(self._pool_size)
         servicer = _face_implementations.servicer(
             self._pool, self._breakdown.implementations, None)
         self._back = _base_implementations.back_link(
@@ -114,7 +117,8 @@ class _Stub(interfaces.Stub):
 
   def __init__(
       self, breakdown, host, port, secure, root_certificates, private_key,
-      certificate_chain, metadata_transformer=None, server_host_override=None):
+      certificate_chain, metadata_transformer=None, server_host_override=None,
+      thread_pool_size=_DEFAULT_THREAD_POOL_SIZE):
     self._lock = threading.Lock()
     self._breakdown = breakdown
     self._host = host
@@ -126,6 +130,7 @@ class _Stub(interfaces.Stub):
     self._metadata_transformer = metadata_transformer
     self._server_host_override = server_host_override
 
+    self._pool_size = thread_pool_size
     self._pool = None
     self._front = None
     self._rear_link = None
@@ -134,7 +139,7 @@ class _Stub(interfaces.Stub):
   def __enter__(self):
     with self._lock:
       if self._pool is None:
-        self._pool = logging_pool.pool(_THREAD_POOL_SIZE)
+        self._pool = logging_pool.pool(self._pool_size)
         self._front = _base_implementations.front_link(
             self._pool, self._pool, self._pool)
         self._rear_link = _rear.RearLink(
@@ -193,7 +198,7 @@ class _Stub(interfaces.Stub):
 def stub(
     service_name, methods, host, port, metadata_transformer=None, secure=False,
     root_certificates=None, private_key=None, certificate_chain=None,
-    server_host_override=None):
+    server_host_override=None, thread_pool_size=_DEFAULT_THREAD_POOL_SIZE):
   """Constructs an interfaces.Stub.
 
   Args:
@@ -216,6 +221,8 @@ def stub(
       certificate chain should be used.
     server_host_override: (For testing only) the target name used for SSL
       host name checking.
+    thread_pool_size: The maximum number of threads to allow in the backing
+      thread pool.
 
   Returns:
     An interfaces.Stub affording RPC invocation.
@@ -224,11 +231,13 @@ def stub(
   return _Stub(
       breakdown, host, port, secure, root_certificates, private_key,
       certificate_chain, server_host_override=server_host_override,
-      metadata_transformer=metadata_transformer)
+      metadata_transformer=metadata_transformer,
+      thread_pool_size=thread_pool_size)
 
 
 def server(
-    service_name, methods, port, private_key=None, certificate_chain=None):
+    service_name, methods, port, private_key=None, certificate_chain=None,
+    thread_pool_size=_DEFAULT_THREAD_POOL_SIZE):
   """Constructs an interfaces.Server.
 
   Args:
@@ -242,9 +251,12 @@ def server(
     private_key: A pem-encoded private key, or None for an insecure server.
     certificate_chain: A pem-encoded certificate chain, or None for an insecure
       server.
+    thread_pool_size: The maximum number of threads to allow in the backing
+      thread pool.
 
   Returns:
     An interfaces.Server that will serve secure traffic.
   """
   breakdown = _face_utilities.break_down_service(service_name, methods)
-  return _Server(breakdown, port, private_key, certificate_chain)
+  return _Server(breakdown, port, private_key, certificate_chain,
+      thread_pool_size=thread_pool_size)
diff --git a/src/ruby/bin/interop/test/cpp/interop/test.rb b/src/python/grpcio/grpc/framework/core/__init__.py
index 5948b50eaa..7086519106 100644
--- a/src/ruby/bin/interop/test/cpp/interop/test.rb
+++ b/src/python/grpcio/grpc/framework/core/__init__.py
@@ -27,17 +27,4 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-# Generated by the protocol buffer compiler.  DO NOT EDIT!
-# source: test/cpp/interop/test.proto
 
-require 'google/protobuf'
-
-require 'test/cpp/interop/empty'
-require 'test/cpp/interop/messages'
-Google::Protobuf::DescriptorPool.generated_pool.build do
-end
-
-module Grpc
-  module Testing
-  end
-end
diff --git a/src/python/grpcio/grpc/framework/core/_constants.py b/src/python/grpcio/grpc/framework/core/_constants.py
new file mode 100644
index 0000000000..d3be3a4c4a
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_constants.py
@@ -0,0 +1,59 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Private constants for the package."""
+
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.links import links
+
+TICKET_SUBSCRIPTION_FOR_BASE_SUBSCRIPTION_KIND = {
+    base.Subscription.Kind.NONE: links.Ticket.Subscription.NONE,
+    base.Subscription.Kind.TERMINATION_ONLY:
+        links.Ticket.Subscription.TERMINATION,
+    base.Subscription.Kind.FULL: links.Ticket.Subscription.FULL,
+    }
+
+# Mapping from abortive operation outcome to ticket termination to be
+# sent to the other side of the operation, or None to indicate that no
+# ticket should be sent to the other side in the event of such an
+# outcome.
+ABORTION_OUTCOME_TO_TICKET_TERMINATION = {
+    base.Outcome.CANCELLED: links.Ticket.Termination.CANCELLATION,
+    base.Outcome.EXPIRED: links.Ticket.Termination.EXPIRATION,
+    base.Outcome.LOCAL_SHUTDOWN: links.Ticket.Termination.SHUTDOWN,
+    base.Outcome.REMOTE_SHUTDOWN: None,
+    base.Outcome.RECEPTION_FAILURE: links.Ticket.Termination.RECEPTION_FAILURE,
+    base.Outcome.TRANSMISSION_FAILURE: None,
+    base.Outcome.LOCAL_FAILURE: links.Ticket.Termination.LOCAL_FAILURE,
+    base.Outcome.REMOTE_FAILURE: links.Ticket.Termination.REMOTE_FAILURE,
+}
+
+INTERNAL_ERROR_LOG_MESSAGE = ':-( RPC Framework (Core) internal error! )-:'
+TERMINATION_CALLBACK_EXCEPTION_LOG_MESSAGE = (
+    'Exception calling termination callback!')
diff --git a/src/python/grpcio/grpc/framework/core/_context.py b/src/python/grpcio/grpc/framework/core/_context.py
new file mode 100644
index 0000000000..24a12b612e
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_context.py
@@ -0,0 +1,92 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for operation context."""
+
+import time
+
+# _interfaces is referenced from specification in this module.
+from grpc.framework.core import _interfaces  # pylint: disable=unused-import
+from grpc.framework.interfaces.base import base
+
+
+class OperationContext(base.OperationContext):
+  """An implementation of interfaces.OperationContext."""
+
+  def __init__(
+      self, lock, termination_manager, transmission_manager,
+      expiration_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+
+  def _abort(self, outcome):
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        self._termination_manager.abort(outcome)
+        self._transmission_manager.abort(outcome)
+        self._expiration_manager.terminate()
+
+  def outcome(self):
+    """See base.OperationContext.outcome for specification."""
+    with self._lock:
+      return self._termination_manager.outcome
+
+  def add_termination_callback(self, callback):
+    """See base.OperationContext.add_termination_callback."""
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        self._termination_manager.add_callback(callback)
+        return None
+      else:
+        return self._termination_manager.outcome
+
+  def time_remaining(self):
+    """See base.OperationContext.time_remaining for specification."""
+    with self._lock:
+      deadline = self._expiration_manager.deadline()
+    return max(0.0, deadline - time.time())
+
+  def cancel(self):
+    """See base.OperationContext.cancel for specification."""
+    self._abort(base.Outcome.CANCELLED)
+
+  def fail(self, exception):
+    """See base.OperationContext.fail for specification."""
+    self._abort(base.Outcome.LOCAL_FAILURE)
diff --git a/src/python/grpcio/grpc/framework/core/_emission.py b/src/python/grpcio/grpc/framework/core/_emission.py
new file mode 100644
index 0000000000..7c702ab2ce
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_emission.py
@@ -0,0 +1,97 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for handling emitted values."""
+
+from grpc.framework.core import _interfaces
+from grpc.framework.interfaces.base import base
+
+
+class EmissionManager(_interfaces.EmissionManager):
+  """An EmissionManager implementation."""
+
+  def __init__(
+      self, lock, termination_manager, transmission_manager,
+      expiration_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+    self._ingestion_manager = None
+
+    self._initial_metadata_seen = False
+    self._payload_seen = False
+    self._completion_seen = False
+
+  def set_ingestion_manager(self, ingestion_manager):
+    """Sets the ingestion manager with which this manager will cooperate.
+
+    Args:
+      ingestion_manager: The _interfaces.IngestionManager for the operation.
+    """
+    self._ingestion_manager = ingestion_manager
+
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    initial_metadata_present = initial_metadata is not None
+    payload_present = payload is not None
+    completion_present = completion is not None
+    allowance_present = allowance is not None
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        if (initial_metadata_present and (
+                self._initial_metadata_seen or self._payload_seen or
+                self._completion_seen) or
+            payload_present and self._completion_seen or
+            completion_present and self._completion_seen or
+            allowance_present and allowance <= 0):
+          self._termination_manager.abort(base.Outcome.LOCAL_FAILURE)
+          self._transmission_manager.abort(base.Outcome.LOCAL_FAILURE)
+          self._expiration_manager.terminate()
+        else:
+          self._initial_metadata_seen |= initial_metadata_present
+          self._payload_seen |= payload_present
+          self._completion_seen |= completion_present
+          if completion_present:
+            self._termination_manager.emission_complete()
+            self._ingestion_manager.local_emissions_done()
+          self._transmission_manager.advance(
+              initial_metadata, payload, completion, allowance)
+          if allowance_present:
+            self._ingestion_manager.add_local_allowance(allowance)
diff --git a/src/python/grpcio/grpc/framework/core/_end.py b/src/python/grpcio/grpc/framework/core/_end.py
new file mode 100644
index 0000000000..fb2c532df6
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_end.py
@@ -0,0 +1,251 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Implementation of base.End."""
+
+import abc
+import enum
+import threading
+import uuid
+
+from grpc.framework.core import _operation
+from grpc.framework.core import _utilities
+from grpc.framework.foundation import callable_util
+from grpc.framework.foundation import later
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.links import links
+from grpc.framework.interfaces.links import utilities
+
+_IDLE_ACTION_EXCEPTION_LOG_MESSAGE = 'Exception calling idle action!'
+
+
+class End(base.End, links.Link):
+  """A bridge between base.End and links.Link.
+
+  Implementations of this interface translate arriving tickets into
+  calls on application objects implementing base interfaces and
+  translate calls from application objects implementing base interfaces
+  into tickets sent to a joined link.
+  """
+  __metaclass__ = abc.ABCMeta
+
+
+class _Cycle(object):
+  """State for a single start-stop End lifecycle."""
+
+  def __init__(self, pool):
+    self.pool = pool
+    self.grace = False
+    self.futures = []
+    self.operations = {}
+    self.idle_actions = []
+
+
+def _abort(operations):
+  for operation in operations:
+    operation.abort(base.Outcome.LOCAL_SHUTDOWN)
+
+
+def _cancel_futures(futures):
+  for future in futures:
+    futures.cancel()
+
+
+def _future_shutdown(lock, cycle, event):
+  def in_future():
+    with lock:
+      _abort(cycle.operations.values())
+      _cancel_futures(cycle.futures)
+      pool = cycle.pool
+    cycle.pool.shutdown(wait=True)
+  return in_future
+
+
+def _termination_action(lock, stats, operation_id, cycle):
+  """Constructs the termination action for a single operation.
+
+  Args:
+    lock: A lock to hold during the termination action.
+    states: A mapping from base.Outcome values to integers to increment with
+      the outcome given to the termination action.
+    operation_id: The operation ID for the termination action.
+    cycle: A _Cycle value to be updated during the termination action.
+
+  Returns:
+    A callable that takes an operation outcome as its sole parameter and that
+      should be used as the termination action for the operation associated
+      with the given operation ID.
+  """
+  def termination_action(outcome):
+    with lock:
+      stats[outcome] += 1
+      cycle.operations.pop(operation_id, None)
+      if not cycle.operations:
+        for action in cycle.idle_actions:
+          cycle.pool.submit(action)
+        cycle.idle_actions = []
+        if cycle.grace:
+          _cancel_futures(cycle.futures)
+  return termination_action
+
+
+class _End(End):
+  """An End implementation."""
+
+  def __init__(self, servicer_package):
+    """Constructor.
+
+    Args:
+      servicer_package: A _ServicerPackage for servicing operations or None if
+        this end will not be used to service operations.
+    """
+    self._lock = threading.Condition()
+    self._servicer_package = servicer_package
+
+    self._stats = {outcome: 0 for outcome in base.Outcome}
+
+    self._mate = None
+
+    self._cycle = None
+
+  def start(self):
+    """See base.End.start for specification."""
+    with self._lock:
+      if self._cycle is not None:
+        raise ValueError('Tried to start a not-stopped End!')
+      else:
+        self._cycle = _Cycle(logging_pool.pool(1))
+
+  def stop(self, grace):
+    """See base.End.stop for specification."""
+    with self._lock:
+      if self._cycle is None:
+        event = threading.Event()
+        event.set()
+        return event
+      elif not self._cycle.operations:
+        event = threading.Event()
+        self._cycle.pool.submit(event.set)
+        self._cycle.pool.shutdown(wait=False)
+        self._cycle = None
+        return event
+      else:
+        self._cycle.grace = True
+        event = threading.Event()
+        self._cycle.idle_actions.append(event.set)
+        if 0 < grace:
+          future = later.later(
+              grace, _future_shutdown(self._lock, self._cycle, event))
+          self._cycle.futures.append(future)
+        else:
+          _abort(self._cycle.operations.values())
+        return event
+
+  def operate(
+      self, group, method, subscription, timeout, initial_metadata=None,
+      payload=None, completion=None):
+    """See base.End.operate for specification."""
+    operation_id = uuid.uuid4()
+    with self._lock:
+      if self._cycle is None or self._cycle.grace:
+        raise ValueError('Can\'t operate on stopped or stopping End!')
+      termination_action = _termination_action(
+          self._lock, self._stats, operation_id, self._cycle)
+      operation = _operation.invocation_operate(
+          operation_id, group, method, subscription, timeout, initial_metadata,
+          payload, completion, self._mate.accept_ticket, termination_action,
+          self._cycle.pool)
+      self._cycle.operations[operation_id] = operation
+      return operation.context, operation.operator
+
+  def operation_stats(self):
+    """See base.End.operation_stats for specification."""
+    with self._lock:
+      return dict(self._stats)
+
+  def add_idle_action(self, action):
+    """See base.End.add_idle_action for specification."""
+    with self._lock:
+      if self._cycle is None:
+        raise ValueError('Can\'t add idle action to stopped End!')
+      action_with_exceptions_logged = callable_util.with_exceptions_logged(
+          action, _IDLE_ACTION_EXCEPTION_LOG_MESSAGE)
+      if self._cycle.operations:
+        self._cycle.idle_actions.append(action_with_exceptions_logged)
+      else:
+        self._cycle.pool.submit(action_with_exceptions_logged)
+
+  def accept_ticket(self, ticket):
+    """See links.Link.accept_ticket for specification."""
+    with self._lock:
+      if self._cycle is not None and not self._cycle.grace:
+        operation = self._cycle.operations.get(ticket.operation_id)
+        if operation is not None:
+          operation.handle_ticket(ticket)
+        elif self._servicer_package is not None:
+          termination_action = _termination_action(
+              self._lock, self._stats, ticket.operation_id, self._cycle)
+          operation = _operation.service_operate(
+              self._servicer_package, ticket, self._mate.accept_ticket,
+              termination_action, self._cycle.pool)
+          if operation is not None:
+            self._cycle.operations[ticket.operation_id] = operation
+
+  def join_link(self, link):
+    """See links.Link.join_link for specification."""
+    with self._lock:
+      self._mate = utilities.NULL_LINK if link is None else link
+
+
+def serviceless_end_link():
+  """Constructs an End usable only for invoking operations.
+
+  Returns:
+    An End usable for translating operations into ticket exchange.
+  """
+  return _End(None)
+
+
+def serviceful_end_link(servicer, default_timeout, maximum_timeout):
+  """Constructs an End capable of servicing operations.
+
+  Args:
+    servicer: An interfaces.Servicer for servicing operations.
+    default_timeout: A length of time in seconds to be used as the default
+      time alloted for a single operation.
+    maximum_timeout: A length of time in seconds to be used as the maximum
+      time alloted for a single operation.
+
+  Returns:
+    An End capable of servicing the operations requested of it through ticket
+      exchange.
+  """
+  return _End(
+      _utilities.ServicerPackage(servicer, default_timeout, maximum_timeout))
diff --git a/src/python/grpcio/grpc/framework/core/_expiration.py b/src/python/grpcio/grpc/framework/core/_expiration.py
new file mode 100644
index 0000000000..d94bdf2d2b
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_expiration.py
@@ -0,0 +1,152 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for operation expiration."""
+
+import time
+
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import later
+from grpc.framework.interfaces.base import base
+
+
+class _ExpirationManager(_interfaces.ExpirationManager):
+  """An implementation of _interfaces.ExpirationManager."""
+
+  def __init__(
+      self, commencement, timeout, maximum_timeout, lock, termination_manager,
+      transmission_manager):
+    """Constructor.
+
+    Args:
+      commencement: The time in seconds since the epoch at which the operation
+        began.
+      timeout: A length of time in seconds to allow for the operation to run.
+      maximum_timeout: The maximum length of time in seconds to allow for the
+        operation to run despite what is requested via this object's
+        change_timout method.
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._commencement = commencement
+    self._maximum_timeout = maximum_timeout
+
+    self._timeout = timeout
+    self._deadline = commencement + timeout
+    self._index = None
+    self._future = None
+
+  def _expire(self, index):
+    def expire():
+      with self._lock:
+        if self._future is not None and index == self._index:
+          self._future = None
+          self._termination_manager.expire()
+          self._transmission_manager.abort(base.Outcome.EXPIRED)
+    return expire
+
+  def start(self):
+    self._index = 0
+    self._future = later.later(self._timeout, self._expire(0))
+
+  def change_timeout(self, timeout):
+    if self._future is not None and timeout != self._timeout:
+      self._future.cancel()
+      new_timeout = min(timeout, self._maximum_timeout)
+      new_index = self._index + 1
+      self._timeout = new_timeout
+      self._deadline = self._commencement + new_timeout
+      self._index = new_index
+      delay = self._deadline - time.time()
+      self._future = later.later(delay, self._expire(new_index))
+      if new_timeout != timeout:
+        self._transmission_manager.timeout(new_timeout)
+
+  def deadline(self):
+    return self._deadline
+
+  def terminate(self):
+    if self._future:
+      self._future.cancel()
+      self._future = None
+    self._deadline_index = None
+
+
+def invocation_expiration_manager(
+    timeout, lock, termination_manager, transmission_manager):
+  """Creates an _interfaces.ExpirationManager appropriate for front-side use.
+
+  Args:
+    timeout: A length of time in seconds to allow for the operation to run.
+    lock: The operation-wide lock.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+
+  Returns:
+    An _interfaces.ExpirationManager appropriate for invocation-side use.
+  """
+  expiration_manager = _ExpirationManager(
+      time.time(), timeout, timeout, lock, termination_manager,
+      transmission_manager)
+  expiration_manager.start()
+  return expiration_manager
+
+
+def service_expiration_manager(
+    timeout, default_timeout, maximum_timeout, lock, termination_manager,
+    transmission_manager):
+  """Creates an _interfaces.ExpirationManager appropriate for back-side use.
+
+  Args:
+    timeout: A length of time in seconds to allow for the operation to run. May
+      be None in which case default_timeout will be used.
+    default_timeout: The default length of time in seconds to allow for the
+      operation to run if the front-side customer has not specified such a value
+      (or if the value they specified is not yet known).
+    maximum_timeout: The maximum length of time in seconds to allow for the
+      operation to run.
+    lock: The operation-wide lock.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+
+  Returns:
+    An _interfaces.ExpirationManager appropriate for service-side use.
+  """
+  expiration_manager = _ExpirationManager(
+      time.time(), default_timeout if timeout is None else timeout,
+      maximum_timeout, lock, termination_manager, transmission_manager)
+  expiration_manager.start()
+  return expiration_manager
diff --git a/src/python/grpcio/grpc/framework/core/_ingestion.py b/src/python/grpcio/grpc/framework/core/_ingestion.py
new file mode 100644
index 0000000000..59f7f8adc8
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_ingestion.py
@@ -0,0 +1,410 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for ingestion during an operation."""
+
+import abc
+import collections
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import abandonment
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+
+_CREATE_SUBSCRIPTION_EXCEPTION_LOG_MESSAGE = 'Exception initializing ingestion!'
+_INGESTION_EXCEPTION_LOG_MESSAGE = 'Exception during ingestion!'
+
+
+class _SubscriptionCreation(collections.namedtuple(
+    '_SubscriptionCreation', ('subscription', 'remote_error', 'abandoned'))):
+  """A sum type for the outcome of ingestion initialization.
+
+  Either subscription will be non-None, remote_error will be True, or abandoned
+  will be True.
+
+  Attributes:
+    subscription: A base.Subscription describing the customer's interest in
+      operation values from the other side.
+    remote_error: A boolean indicating that the subscription could not be
+      created due to an error on the remote side of the operation.
+    abandoned: A boolean indicating that subscription creation was abandoned.
+  """
+
+
+class _SubscriptionCreator(object):
+  """Common specification of subscription-creating behavior."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def create(self, group, method):
+    """Creates the base.Subscription of the local customer.
+
+    Any exceptions raised by this method should be attributed to and treated as
+    defects in the customer code called by this method.
+
+    Args:
+      group: The group identifier of the operation.
+      method: The method identifier of the operation.
+
+    Returns:
+      A _SubscriptionCreation describing the result of subscription creation.
+    """
+    raise NotImplementedError()
+
+
+class _ServiceSubscriptionCreator(_SubscriptionCreator):
+  """A _SubscriptionCreator appropriate for service-side use."""
+
+  def __init__(self, servicer, operation_context, output_operator):
+    """Constructor.
+
+    Args:
+      servicer: The base.Servicer that will service the operation.
+      operation_context: A base.OperationContext for the operation to be passed
+        to the customer.
+      output_operator: A base.Operator for the operation to be passed to the
+        customer and to be called by the customer to accept operation data
+        emitted by the customer.
+    """
+    self._servicer = servicer
+    self._operation_context = operation_context
+    self._output_operator = output_operator
+
+  def create(self, group, method):
+    try:
+      subscription = self._servicer.service(
+          group, method, self._operation_context, self._output_operator)
+    except base.NoSuchMethodError:
+      return _SubscriptionCreation(None, True, False)
+    except abandonment.Abandoned:
+      return _SubscriptionCreation(None, False, True)
+    else:
+      return _SubscriptionCreation(subscription, False, False)
+
+
+def _wrap(behavior):
+  def wrapped(*args, **kwargs):
+    try:
+      behavior(*args, **kwargs)
+    except abandonment.Abandoned:
+      return False
+    else:
+      return True
+  return wrapped
+
+
+class _IngestionManager(_interfaces.IngestionManager):
+  """An implementation of _interfaces.IngestionManager."""
+
+  def __init__(
+      self, lock, pool, subscription, subscription_creator, termination_manager,
+      transmission_manager, expiration_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      pool: A thread pool in which to execute customer code.
+      subscription: A base.Subscription describing the customer's interest in
+        operation values from the other side. May be None if
+        subscription_creator is not None.
+      subscription_creator: A _SubscriptionCreator wrapping the portion of
+        customer code that when called returns the base.Subscription describing
+        the customer's interest in operation values from the other side. May be
+        None if subscription is not None.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+    """
+    self._lock = lock
+    self._pool = pool
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+
+    if subscription is None:
+      self._subscription_creator = subscription_creator
+      self._wrapped_operator = None
+    elif subscription.kind is base.Subscription.Kind.FULL:
+      self._subscription_creator = None
+      self._wrapped_operator = _wrap(subscription.operator.advance)
+    else:
+      # TODO(nathaniel): Support other subscriptions.
+      raise ValueError('Unsupported subscription "%s"!' % subscription.kind)
+    self._pending_initial_metadata = None
+    self._pending_payloads = []
+    self._pending_completion = None
+    self._local_allowance = 1
+    # A nonnegative integer or None, with None indicating that the local
+    # customer is done emitting anyway so there's no need to bother it by
+    # informing it that the remote customer has granted it further permission to
+    # emit.
+    self._remote_allowance = 0
+    self._processing = False
+
+  def _abort_internal_only(self):
+    self._subscription_creator = None
+    self._wrapped_operator = None
+    self._pending_initial_metadata = None
+    self._pending_payloads = None
+    self._pending_completion = None
+
+  def _abort_and_notify(self, outcome):
+    self._abort_internal_only()
+    self._termination_manager.abort(outcome)
+    self._transmission_manager.abort(outcome)
+    self._expiration_manager.terminate()
+
+  def _operator_next(self):
+    """Computes the next step for full-subscription ingestion.
+
+    Returns:
+      An initial_metadata, payload, completion, allowance, continue quintet
+        indicating what operation values (if any) are available to pass into
+        customer code and whether or not there is anything immediately
+        actionable to call customer code to do.
+    """
+    if self._wrapped_operator is None:
+      return None, None, None, None, False
+    else:
+      initial_metadata, payload, completion, allowance, action = [None] * 5
+      if self._pending_initial_metadata is not None:
+        initial_metadata = self._pending_initial_metadata
+        self._pending_initial_metadata = None
+        action = True
+      if self._pending_payloads and 0 < self._local_allowance:
+        payload = self._pending_payloads.pop(0)
+        self._local_allowance -= 1
+        action = True
+      if not self._pending_payloads and self._pending_completion is not None:
+        completion = self._pending_completion
+        self._pending_completion = None
+        action = True
+      if self._remote_allowance is not None and 0 < self._remote_allowance:
+        allowance = self._remote_allowance
+        self._remote_allowance = 0
+        action = True
+      return initial_metadata, payload, completion, allowance, bool(action)
+
+  def _operator_process(
+      self, wrapped_operator, initial_metadata, payload,
+      completion, allowance):
+    while True:
+      advance_outcome = callable_util.call_logging_exceptions(
+          wrapped_operator, _INGESTION_EXCEPTION_LOG_MESSAGE,
+          initial_metadata=initial_metadata, payload=payload,
+          completion=completion, allowance=allowance)
+      if advance_outcome.exception is None:
+        if advance_outcome.return_value:
+          with self._lock:
+            if self._termination_manager.outcome is not None:
+              return
+            if completion is not None:
+              self._termination_manager.ingestion_complete()
+            initial_metadata, payload, completion, allowance, moar = (
+                self._operator_next())
+            if not moar:
+              self._processing = False
+              return
+        else:
+          with self._lock:
+            if self._termination_manager.outcome is None:
+              self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+            return
+      else:
+        with self._lock:
+          if self._termination_manager.outcome is None:
+            self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+          return
+
+  def _operator_post_create(self, subscription):
+    wrapped_operator = _wrap(subscription.operator.advance)
+    with self._lock:
+      if self._termination_manager.outcome is not None:
+        return
+      self._wrapped_operator = wrapped_operator
+      self._subscription_creator = None
+      metadata, payload, completion, allowance, moar = self._operator_next()
+      if not moar:
+        self._processing = False
+        return
+    self._operator_process(
+        wrapped_operator, metadata, payload, completion, allowance)
+
+  def _create(self, subscription_creator, group, name):
+    outcome = callable_util.call_logging_exceptions(
+        subscription_creator.create, _CREATE_SUBSCRIPTION_EXCEPTION_LOG_MESSAGE,
+        group, name)
+    if outcome.return_value is None:
+      with self._lock:
+        if self._termination_manager.outcome is None:
+          self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+    elif outcome.return_value.abandoned:
+      with self._lock:
+        if self._termination_manager.outcome is None:
+          self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+    elif outcome.return_value.remote_error:
+      with self._lock:
+        if self._termination_manager.outcome is None:
+          self._abort_and_notify(base.Outcome.REMOTE_FAILURE)
+    elif outcome.return_value.subscription.kind is base.Subscription.Kind.FULL:
+      self._operator_post_create(outcome.return_value.subscription)
+    else:
+      # TODO(nathaniel): Support other subscriptions.
+      raise ValueError(
+          'Unsupported "%s"!' % outcome.return_value.subscription.kind)
+
+  def _store_advance(self, initial_metadata, payload, completion, allowance):
+    if initial_metadata is not None:
+      self._pending_initial_metadata = initial_metadata
+    if payload is not None:
+      self._pending_payloads.append(payload)
+    if completion is not None:
+      self._pending_completion = completion
+    if allowance is not None and self._remote_allowance is not None:
+      self._remote_allowance += allowance
+
+  def _operator_advance(self, initial_metadata, payload, completion, allowance):
+    if self._processing:
+      self._store_advance(initial_metadata, payload, completion, allowance)
+    else:
+      action = False
+      if initial_metadata is not None:
+        action = True
+      if payload is not None:
+        if 0 < self._local_allowance:
+          self._local_allowance -= 1
+          action = True
+        else:
+          self._pending_payloads.append(payload)
+          payload = False
+      if completion is not None:
+        if self._pending_payloads:
+          self._pending_completion = completion
+        else:
+          action = True
+      if allowance is not None and self._remote_allowance is not None:
+        allowance += self._remote_allowance
+        self._remote_allowance = 0
+        action = True
+      if action:
+        self._pool.submit(
+            callable_util.with_exceptions_logged(
+                self._operator_process, _constants.INTERNAL_ERROR_LOG_MESSAGE),
+            self._wrapped_operator, initial_metadata, payload, completion,
+            allowance)
+
+  def set_group_and_method(self, group, method):
+    """See _interfaces.IngestionManager.set_group_and_method for spec."""
+    if self._subscription_creator is not None and not self._processing:
+      self._pool.submit(
+          callable_util.with_exceptions_logged(
+              self._create, _constants.INTERNAL_ERROR_LOG_MESSAGE),
+          self._subscription_creator, group, method)
+      self._processing = True
+
+  def add_local_allowance(self, allowance):
+    """See _interfaces.IngestionManager.add_local_allowance for spec."""
+    if any((self._subscription_creator, self._wrapped_operator,)):
+      self._local_allowance += allowance
+      if not self._processing:
+        initial_metadata, payload, completion, allowance, moar = (
+            self._operator_next())
+        if moar:
+          self._pool.submit(
+              callable_util.with_exceptions_logged(
+                  self._operator_process,
+                  _constants.INTERNAL_ERROR_LOG_MESSAGE),
+              initial_metadata, payload, completion, allowance)
+
+  def local_emissions_done(self):
+    self._remote_allowance = None
+
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """See _interfaces.IngestionManager.advance for specification."""
+    if self._subscription_creator is not None:
+      self._store_advance(initial_metadata, payload, completion, allowance)
+    elif self._wrapped_operator is not None:
+      self._operator_advance(initial_metadata, payload, completion, allowance)
+
+
+def invocation_ingestion_manager(
+    subscription, lock, pool, termination_manager, transmission_manager,
+    expiration_manager):
+  """Creates an IngestionManager appropriate for invocation-side use.
+
+  Args:
+    subscription: A base.Subscription indicating the customer's interest in the
+      data and results from the service-side of the operation.
+    lock: The operation-wide lock.
+    pool: A thread pool in which to execute customer code.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+    expiration_manager: The _interfaces.ExpirationManager for the operation.
+
+  Returns:
+    An IngestionManager appropriate for invocation-side use.
+  """
+  return _IngestionManager(
+      lock, pool, subscription, None, termination_manager, transmission_manager,
+      expiration_manager)
+
+
+def service_ingestion_manager(
+    servicer, operation_context, output_operator, lock, pool,
+    termination_manager, transmission_manager, expiration_manager):
+  """Creates an IngestionManager appropriate for service-side use.
+
+  The returned IngestionManager will require its set_group_and_name method to be
+  called before its advance method may be called.
+
+  Args:
+    servicer: A base.Servicer for servicing the operation.
+    operation_context: A base.OperationContext for the operation to be passed to
+      the customer.
+    output_operator: A base.Operator for the operation to be passed to the
+      customer and to be called by the customer to accept operation data output
+      by the customer.
+    lock: The operation-wide lock.
+    pool: A thread pool in which to execute customer code.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+    expiration_manager: The _interfaces.ExpirationManager for the operation.
+
+  Returns:
+    An IngestionManager appropriate for service-side use.
+  """
+  subscription_creator = _ServiceSubscriptionCreator(
+      servicer, operation_context, output_operator)
+  return _IngestionManager(
+      lock, pool, None, subscription_creator, termination_manager,
+      transmission_manager, expiration_manager)
diff --git a/src/python/grpcio/grpc/framework/core/_interfaces.py b/src/python/grpcio/grpc/framework/core/_interfaces.py
new file mode 100644
index 0000000000..a626b9f767
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_interfaces.py
@@ -0,0 +1,308 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Package-internal interfaces."""
+
+import abc
+
+from grpc.framework.interfaces.base import base
+
+
+class TerminationManager(object):
+  """An object responsible for handling the termination of an operation.
+
+  Attributes:
+    outcome: None if the operation is active or a base.Outcome value if it has
+      terminated.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def add_callback(self, callback):
+    """Registers a callback to be called on operation termination.
+
+    If the operation has already terminated the callback will not be called.
+
+    Args:
+      callback: A callable that will be passed an interfaces.Outcome value.
+
+    Returns:
+      None if the operation has not yet terminated and the passed callback will
+        be called when it does, or a base.Outcome value describing the operation
+        termination if the operation has terminated and the callback will not be
+        called as a result of this method call.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def emission_complete(self):
+    """Indicates that emissions from customer code have completed."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def transmission_complete(self):
+    """Indicates that transmissions to the remote end are complete.
+
+    Returns:
+      True if the operation has terminated or False if the operation remains
+        ongoing.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def reception_complete(self):
+    """Indicates that reception from the other side is complete."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def ingestion_complete(self):
+    """Indicates that customer code ingestion of received values is complete."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def expire(self):
+    """Indicates that the operation must abort because it has taken too long."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def abort(self, outcome):
+    """Indicates that the operation must abort for the indicated reason.
+
+    Args:
+      outcome: An interfaces.Outcome indicating operation abortion.
+    """
+    raise NotImplementedError()
+
+
+class TransmissionManager(object):
+  """A manager responsible for transmitting to the other end of an operation."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def kick_off(
+      self, group, method, timeout, initial_metadata, payload, completion,
+      allowance):
+    """Transmits the values associated with operation invocation."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """Accepts values for transmission to the other end of the operation.
+
+    Args:
+      initial_metadata: An initial metadata value to be transmitted to the other
+        side of the operation. May only ever be non-None once.
+      payload: A payload value.
+      completion: A base.Completion value. May only ever be non-None in the last
+        transmission to be made to the other side.
+      allowance: A positive integer communicating the number of additional
+        payloads allowed to be transmitted from the other side to this side of
+        the operation, or None if no additional allowance is being granted in
+        this call.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def timeout(self, timeout):
+    """Accepts for transmission to the other side a new timeout value.
+
+    Args:
+      timeout: A positive float used as the new timeout value for the operation
+        to be transmitted to the other side.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def allowance(self, allowance):
+    """Indicates to this manager that the remote customer is allowing payloads.
+
+    Args:
+      allowance: A positive integer indicating the number of additional payloads
+        the remote customer is allowing to be transmitted from this side of the
+        operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def remote_complete(self):
+    """Indicates to this manager that data from the remote side is complete."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def abort(self, outcome):
+    """Indicates that the operation has aborted.
+
+    Args:
+      outcome: An interfaces.Outcome for the operation. If None, indicates that
+        the operation abortion should not be communicated to the other side of
+        the operation.
+    """
+    raise NotImplementedError()
+
+
+class ExpirationManager(object):
+  """A manager responsible for aborting the operation if it runs out of time."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def change_timeout(self, timeout):
+    """Changes the timeout allotted for the operation.
+
+    Operation duration is always measure from the beginning of the operation;
+    calling this method changes the operation's allotted time to timeout total
+    seconds, not timeout seconds from the time of this method call.
+
+    Args:
+      timeout: A length of time in seconds to allow for the operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deadline(self):
+    """Returns the time until which the operation is allowed to run.
+
+    Returns:
+      The time (seconds since the epoch) at which the operation will expire.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminate(self):
+    """Indicates to this manager that the operation has terminated."""
+    raise NotImplementedError()
+
+
+class EmissionManager(base.Operator):
+  """A manager of values emitted by customer code."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    """Accepts a value emitted by customer code.
+
+    This method should only be called by customer code.
+
+    Args:
+      initial_metadata: An initial metadata value emitted by the local customer
+        to be sent to the other side of the operation.
+      payload: A payload value emitted by the local customer to be sent to the
+        other side of the operation.
+      completion: A Completion value emitted by the local customer to be sent to
+        the other side of the operation.
+      allowance: A positive integer indicating an additional number of payloads
+        that the local customer is willing to accept from the other side of the
+        operation.
+    """
+    raise NotImplementedError()
+
+
+class IngestionManager(object):
+  """A manager responsible for executing customer code.
+
+  This name of this manager comes from its responsibility to pass successive
+  values from the other side of the operation into the code of the local
+  customer.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def set_group_and_method(self, group, method):
+    """Communicates to this IngestionManager the operation group and method.
+
+    Args:
+      group: The group identifier of the operation.
+      method: The method identifier of the operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def add_local_allowance(self, allowance):
+    """Communicates to this IngestionManager that more payloads may be ingested.
+
+    Args:
+      allowance: A positive integer indicating an additional number of payloads
+        that the local customer is willing to ingest.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def local_emissions_done(self):
+    """Indicates to this manager that local emissions are done."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """Advances the operation by passing values to the local customer."""
+    raise NotImplementedError()
+
+
+class ReceptionManager(object):
+  """A manager responsible for receiving tickets from the other end."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def receive_ticket(self, ticket):
+    """Handle a ticket from the other side of the operation.
+
+    Args:
+      ticket: An interfaces.BackToFrontTicket or interfaces.FrontToBackTicket
+        appropriate to this end of the operation and this object.
+    """
+    raise NotImplementedError()
+
+
+class Operation(object):
+  """An ongoing operation.
+
+  Attributes:
+    context: A base.OperationContext object for the operation.
+    operator: A base.Operator object for the operation for use by the customer
+      of the operation.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def handle_ticket(self, ticket):
+    """Handle a ticket from the other side of the operation.
+
+    Args:
+      ticket: A links.Ticket from the other side of the operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def abort(self, outcome):
+    """Aborts the operation.
+
+    Args:
+      outcome: A base.Outcome value indicating operation abortion.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio/grpc/framework/core/_operation.py b/src/python/grpcio/grpc/framework/core/_operation.py
new file mode 100644
index 0000000000..d20e40a53d
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_operation.py
@@ -0,0 +1,192 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Implementation of operations."""
+
+import threading
+
+# _utilities is referenced from specification in this module.
+from grpc.framework.core import _context
+from grpc.framework.core import _emission
+from grpc.framework.core import _expiration
+from grpc.framework.core import _ingestion
+from grpc.framework.core import _interfaces
+from grpc.framework.core import _reception
+from grpc.framework.core import _termination
+from grpc.framework.core import _transmission
+from grpc.framework.core import _utilities  # pylint: disable=unused-import
+
+
+class _EasyOperation(_interfaces.Operation):
+  """A trivial implementation of interfaces.Operation."""
+
+  def __init__(
+      self, lock, termination_manager, transmission_manager, expiration_manager,
+      context, operator, reception_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+      context: A base.OperationContext for use by the customer during the
+        operation.
+      operator: A base.Operator for use by the customer during the operation.
+      reception_manager: The _interfaces.ReceptionManager for the operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+    self._reception_manager = reception_manager
+
+    self.context = context
+    self.operator = operator
+
+  def handle_ticket(self, ticket):
+    with self._lock:
+      self._reception_manager.receive_ticket(ticket)
+
+  def abort(self, outcome):
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        self._termination_manager.abort(outcome)
+        self._transmission_manager.abort(outcome)
+        self._expiration_manager.terminate()
+
+
+def invocation_operate(
+    operation_id, group, method, subscription, timeout, initial_metadata,
+    payload, completion, ticket_sink, termination_action, pool):
+  """Constructs objects necessary for front-side operation management.
+
+  Args:
+    operation_id: An object identifying the operation.
+    group: The group identifier of the operation.
+    method: The method identifier of the operation.
+    subscription: A base.Subscription describing the customer's interest in the
+      results of the operation.
+    timeout: A length of time in seconds to allow for the operation.
+    initial_metadata: An initial metadata value to be sent to the other side of
+      the operation. May be None if the initial metadata will be passed later or
+      if there will be no initial metadata passed at all.
+    payload: The first payload value to be transmitted to the other side. May be
+      None if there is no such value or if the customer chose not to pass it at
+      operation invocation.
+    completion: A base.Completion value indicating the end of values passed to
+      the other side of the operation.
+    ticket_sink: A callable that accepts links.Tickets and delivers them to the
+      other side of the operation.
+    termination_action: A callable that accepts the outcome of the operation as
+      a base.Outcome value to be called on operation completion.
+    pool: A thread pool with which to do the work of the operation.
+
+  Returns:
+    An _interfaces.Operation for the operation.
+  """
+  lock = threading.Lock()
+  with lock:
+    termination_manager = _termination.invocation_termination_manager(
+        termination_action, pool)
+    transmission_manager = _transmission.TransmissionManager(
+        operation_id, ticket_sink, lock, pool, termination_manager)
+    expiration_manager = _expiration.invocation_expiration_manager(
+        timeout, lock, termination_manager, transmission_manager)
+    operation_context = _context.OperationContext(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    emission_manager = _emission.EmissionManager(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    ingestion_manager = _ingestion.invocation_ingestion_manager(
+        subscription, lock, pool, termination_manager, transmission_manager,
+        expiration_manager)
+    reception_manager = _reception.ReceptionManager(
+        termination_manager, transmission_manager, expiration_manager,
+        ingestion_manager)
+
+    termination_manager.set_expiration_manager(expiration_manager)
+    transmission_manager.set_expiration_manager(expiration_manager)
+    emission_manager.set_ingestion_manager(ingestion_manager)
+
+    transmission_manager.kick_off(
+        group, method, timeout, initial_metadata, payload, completion, None)
+
+  return _EasyOperation(
+      lock, termination_manager, transmission_manager, expiration_manager,
+      operation_context, emission_manager, reception_manager)
+
+
+def service_operate(
+    servicer_package, ticket, ticket_sink, termination_action, pool):
+  """Constructs an Operation for service of an operation.
+
+  Args:
+    servicer_package: A _utilities.ServicerPackage to be used servicing the
+      operation.
+    ticket: The first links.Ticket received for the operation.
+    ticket_sink: A callable that accepts links.Tickets and delivers them to the
+      other side of the operation.
+    termination_action: A callable that accepts the outcome of the operation as
+      a base.Outcome value to be called on operation completion.
+    pool: A thread pool with which to do the work of the operation.
+
+  Returns:
+    An _interfaces.Operation for the operation.
+  """
+  lock = threading.Lock()
+  with lock:
+    termination_manager = _termination.service_termination_manager(
+        termination_action, pool)
+    transmission_manager = _transmission.TransmissionManager(
+        ticket.operation_id, ticket_sink, lock, pool, termination_manager)
+    expiration_manager = _expiration.service_expiration_manager(
+        ticket.timeout, servicer_package.default_timeout,
+        servicer_package.maximum_timeout, lock, termination_manager,
+        transmission_manager)
+    operation_context = _context.OperationContext(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    emission_manager = _emission.EmissionManager(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    ingestion_manager = _ingestion.service_ingestion_manager(
+        servicer_package.servicer, operation_context, emission_manager, lock,
+        pool, termination_manager, transmission_manager, expiration_manager)
+    reception_manager = _reception.ReceptionManager(
+        termination_manager, transmission_manager, expiration_manager,
+        ingestion_manager)
+
+    termination_manager.set_expiration_manager(expiration_manager)
+    transmission_manager.set_expiration_manager(expiration_manager)
+    emission_manager.set_ingestion_manager(ingestion_manager)
+
+    reception_manager.receive_ticket(ticket)
+
+  return _EasyOperation(
+      lock, termination_manager, transmission_manager, expiration_manager,
+      operation_context, emission_manager, reception_manager)
diff --git a/src/python/grpcio/grpc/framework/core/_reception.py b/src/python/grpcio/grpc/framework/core/_reception.py
new file mode 100644
index 0000000000..0858f64ff6
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_reception.py
@@ -0,0 +1,139 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for ticket reception."""
+
+from grpc.framework.core import _interfaces
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.base import utilities
+from grpc.framework.interfaces.links import links
+
+_REMOTE_TICKET_TERMINATION_TO_LOCAL_OUTCOME = {
+    links.Ticket.Termination.CANCELLATION: base.Outcome.CANCELLED,
+    links.Ticket.Termination.EXPIRATION: base.Outcome.EXPIRED,
+    links.Ticket.Termination.SHUTDOWN: base.Outcome.REMOTE_SHUTDOWN,
+    links.Ticket.Termination.RECEPTION_FAILURE: base.Outcome.RECEPTION_FAILURE,
+    links.Ticket.Termination.TRANSMISSION_FAILURE:
+        base.Outcome.TRANSMISSION_FAILURE,
+    links.Ticket.Termination.LOCAL_FAILURE: base.Outcome.REMOTE_FAILURE,
+    links.Ticket.Termination.REMOTE_FAILURE: base.Outcome.LOCAL_FAILURE,
+}
+
+
+class ReceptionManager(_interfaces.ReceptionManager):
+  """A ReceptionManager based around a _Receiver passed to it."""
+
+  def __init__(
+      self, termination_manager, transmission_manager, expiration_manager,
+      ingestion_manager):
+    """Constructor.
+
+    Args:
+      termination_manager: The operation's _interfaces.TerminationManager.
+      transmission_manager: The operation's _interfaces.TransmissionManager.
+      expiration_manager: The operation's _interfaces.ExpirationManager.
+      ingestion_manager: The operation's _interfaces.IngestionManager.
+    """
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+    self._ingestion_manager = ingestion_manager
+
+    self._lowest_unseen_sequence_number = 0
+    self._out_of_sequence_tickets = {}
+    self._aborted = False
+
+  def _abort(self, outcome):
+    self._aborted = True
+    if self._termination_manager.outcome is None:
+      self._termination_manager.abort(outcome)
+      self._transmission_manager.abort(None)
+      self._expiration_manager.terminate()
+
+  def _sequence_failure(self, ticket):
+    """Determines a just-arrived ticket's sequential legitimacy.
+
+    Args:
+      ticket: A just-arrived ticket.
+
+    Returns:
+      True if the ticket is sequentially legitimate; False otherwise.
+    """
+    if ticket.sequence_number < self._lowest_unseen_sequence_number:
+      return True
+    elif ticket.sequence_number in self._out_of_sequence_tickets:
+      return True
+    else:
+      return False
+
+  def _process_one(self, ticket):
+    if ticket.sequence_number == 0:
+      self._ingestion_manager.set_group_and_method(ticket.group, ticket.method)
+    if ticket.timeout is not None:
+      self._expiration_manager.change_timeout(ticket.timeout)
+    if ticket.termination is None:
+      completion = None
+    else:
+      completion = utilities.completion(
+          ticket.terminal_metadata, ticket.code, ticket.message)
+    self._ingestion_manager.advance(
+        ticket.initial_metadata, ticket.payload, completion, ticket.allowance)
+    if ticket.allowance is not None:
+      self._transmission_manager.allowance(ticket.allowance)
+
+  def _process(self, ticket):
+    """Process those tickets ready to be processed.
+
+    Args:
+      ticket: A just-arrived ticket the sequence number of which matches this
+        _ReceptionManager's _lowest_unseen_sequence_number field.
+    """
+    while True:
+      self._process_one(ticket)
+      next_ticket = self._out_of_sequence_tickets.pop(
+          ticket.sequence_number + 1, None)
+      if next_ticket is None:
+        self._lowest_unseen_sequence_number = ticket.sequence_number + 1
+        return
+      else:
+        ticket = next_ticket
+
+  def receive_ticket(self, ticket):
+    """See _interfaces.ReceptionManager.receive_ticket for specification."""
+    if self._aborted:
+      return
+    elif self._sequence_failure(ticket):
+      self._abort(base.Outcome.RECEPTION_FAILURE)
+    elif ticket.termination not in (None, links.Ticket.Termination.COMPLETION):
+      outcome = _REMOTE_TICKET_TERMINATION_TO_LOCAL_OUTCOME[ticket.termination]
+      self._abort(outcome)
+    elif ticket.sequence_number == self._lowest_unseen_sequence_number:
+      self._process(ticket)
+    else:
+      self._out_of_sequence_tickets[ticket.sequence_number] = ticket
diff --git a/src/python/grpcio/grpc/framework/core/_termination.py b/src/python/grpcio/grpc/framework/core/_termination.py
new file mode 100644
index 0000000000..ad9f6123d8
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_termination.py
@@ -0,0 +1,212 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for operation termination."""
+
+import abc
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+
+
+def _invocation_completion_predicate(
+    unused_emission_complete, unused_transmission_complete,
+    unused_reception_complete, ingestion_complete):
+  return ingestion_complete
+
+
+def _service_completion_predicate(
+    unused_emission_complete, transmission_complete, unused_reception_complete,
+    unused_ingestion_complete):
+  return transmission_complete
+
+
+class TerminationManager(_interfaces.TerminationManager):
+  """A _interfaces.TransmissionManager on which another manager may be set."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def set_expiration_manager(self, expiration_manager):
+    """Sets the expiration manager with which this manager will interact.
+
+    Args:
+      expiration_manager: The _interfaces.ExpirationManager associated with the
+        current operation.
+    """
+    raise NotImplementedError()
+
+
+class _TerminationManager(TerminationManager):
+  """An implementation of TerminationManager."""
+
+  def __init__(self, predicate, action, pool):
+    """Constructor.
+
+    Args:
+      predicate: One of _invocation_completion_predicate or
+        _service_completion_predicate to be used to determine when the operation
+        has completed.
+      action: A behavior to pass the operation outcome on operation termination.
+      pool: A thread pool.
+    """
+    self._predicate = predicate
+    self._action = action
+    self._pool = pool
+    self._expiration_manager = None
+
+    self.outcome = None
+    self._callbacks = []
+
+    self._emission_complete = False
+    self._transmission_complete = False
+    self._reception_complete = False
+    self._ingestion_complete = False
+
+  def set_expiration_manager(self, expiration_manager):
+    self._expiration_manager = expiration_manager
+
+  def _terminate_internal_only(self, outcome):
+    """Terminates the operation.
+
+    Args:
+      outcome: A base.Outcome describing the outcome of the operation.
+    """
+    self.outcome = outcome
+    callbacks = list(self._callbacks)
+    self._callbacks = None
+
+    act = callable_util.with_exceptions_logged(
+        self._action, _constants.INTERNAL_ERROR_LOG_MESSAGE)
+
+    if outcome is base.Outcome.LOCAL_FAILURE:
+      self._pool.submit(act, outcome)
+    else:
+      def call_callbacks_and_act(callbacks, outcome):
+        for callback in callbacks:
+          callback_outcome = callable_util.call_logging_exceptions(
+              callback, _constants.TERMINATION_CALLBACK_EXCEPTION_LOG_MESSAGE,
+              outcome)
+          if callback_outcome.exception is not None:
+            outcome = base.Outcome.LOCAL_FAILURE
+            break
+        act(outcome)
+
+      self._pool.submit(
+          callable_util.with_exceptions_logged(
+              call_callbacks_and_act, _constants.INTERNAL_ERROR_LOG_MESSAGE),
+          callbacks, outcome)
+
+  def _terminate_and_notify(self, outcome):
+    self._terminate_internal_only(outcome)
+    self._expiration_manager.terminate()
+
+  def _perhaps_complete(self):
+    if self._predicate(
+        self._emission_complete, self._transmission_complete,
+        self._reception_complete, self._ingestion_complete):
+      self._terminate_and_notify(base.Outcome.COMPLETED)
+      return True
+    else:
+      return False
+
+  def is_active(self):
+    """See _interfaces.TerminationManager.is_active for specification."""
+    return self.outcome is None
+
+  def add_callback(self, callback):
+    """See _interfaces.TerminationManager.add_callback for specification."""
+    if self.outcome is None:
+      self._callbacks.append(callback)
+      return None
+    else:
+      return self.outcome
+
+  def emission_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._emission_complete = True
+      self._perhaps_complete()
+
+  def transmission_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._transmission_complete = True
+      return self._perhaps_complete()
+    else:
+      return False
+
+  def reception_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._reception_complete = True
+      self._perhaps_complete()
+
+  def ingestion_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._ingestion_complete = True
+      self._perhaps_complete()
+
+  def expire(self):
+    """See _interfaces.TerminationManager.expire for specification."""
+    self._terminate_internal_only(base.Outcome.EXPIRED)
+
+  def abort(self, outcome):
+    """See _interfaces.TerminationManager.abort for specification."""
+    self._terminate_and_notify(outcome)
+
+
+def invocation_termination_manager(action, pool):
+  """Creates a TerminationManager appropriate for invocation-side use.
+
+  Args:
+    action: An action to call on operation termination.
+    pool: A thread pool in which to execute the passed action and any
+      termination callbacks that are registered during the operation.
+
+  Returns:
+    A TerminationManager appropriate for invocation-side use.
+  """
+  return _TerminationManager(_invocation_completion_predicate, action, pool)
+
+
+def service_termination_manager(action, pool):
+  """Creates a TerminationManager appropriate for service-side use.
+
+  Args:
+    action: An action to call on operation termination.
+    pool: A thread pool in which to execute the passed action and any
+      termination callbacks that are registered during the operation.
+
+  Returns:
+    A TerminationManager appropriate for service-side use.
+  """
+  return _TerminationManager(_service_completion_predicate, action, pool)
diff --git a/src/python/grpcio/grpc/framework/core/_transmission.py b/src/python/grpcio/grpc/framework/core/_transmission.py
new file mode 100644
index 0000000000..03644f4d49
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/_transmission.py
@@ -0,0 +1,294 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for ticket transmission during an operation."""
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.links import links
+
+_TRANSMISSION_EXCEPTION_LOG_MESSAGE = 'Exception during transmission!'
+
+
+def _explode_completion(completion):
+  if completion is None:
+    return None, None, None, None
+  else:
+    return (
+        completion.terminal_metadata, completion.code, completion.message,
+        links.Ticket.Termination.COMPLETION)
+
+
+class TransmissionManager(_interfaces.TransmissionManager):
+  """An _interfaces.TransmissionManager that sends links.Tickets."""
+
+  def __init__(
+      self, operation_id, ticket_sink, lock, pool, termination_manager):
+    """Constructor.
+
+    Args:
+      operation_id: The operation's ID.
+      ticket_sink: A callable that accepts tickets and sends them to the other
+        side of the operation.
+      lock: The operation-servicing-wide lock object.
+      pool: A thread pool in which the work of transmitting tickets will be
+        performed.
+      termination_manager: The _interfaces.TerminationManager associated with
+        this operation.
+    """
+    self._lock = lock
+    self._pool = pool
+    self._ticket_sink = ticket_sink
+    self._operation_id = operation_id
+    self._termination_manager = termination_manager
+    self._expiration_manager = None
+
+    self._lowest_unused_sequence_number = 0
+    self._remote_allowance = 1
+    self._remote_complete = False
+    self._timeout = None
+    self._local_allowance = 0
+    self._initial_metadata = None
+    self._payloads = []
+    self._completion = None
+    self._aborted = False
+    self._abortion_outcome = None
+    self._transmitting = False
+
+  def set_expiration_manager(self, expiration_manager):
+    """Sets the ExpirationManager with which this manager will cooperate."""
+    self._expiration_manager = expiration_manager
+
+  def _next_ticket(self):
+    """Creates the next ticket to be transmitted.
+
+    Returns:
+      A links.Ticket to be sent to the other side of the operation or None if
+        there is nothing to be sent at this time.
+    """
+    if self._aborted:
+      if self._abortion_outcome is None:
+        return None
+      else:
+        termination = _constants.ABORTION_OUTCOME_TO_TICKET_TERMINATION[
+            self._abortion_outcome]
+        if termination is None:
+          return None
+        else:
+          self._abortion_outcome = None
+          return links.Ticket(
+              self._operation_id, self._lowest_unused_sequence_number, None,
+              None, None, None, None, None, None, None, None, None,
+              termination, None)
+
+    action = False
+    # TODO(nathaniel): Support other subscriptions.
+    local_subscription = links.Ticket.Subscription.FULL
+    timeout = self._timeout
+    if timeout is not None:
+      self._timeout = None
+      action = True
+    if self._local_allowance <= 0:
+      allowance = None
+    else:
+      allowance = self._local_allowance
+      self._local_allowance = 0
+      action = True
+    initial_metadata = self._initial_metadata
+    if initial_metadata is not None:
+      self._initial_metadata = None
+      action = True
+    if not self._payloads or self._remote_allowance <= 0:
+      payload = None
+    else:
+      payload = self._payloads.pop(0)
+      self._remote_allowance -= 1
+      action = True
+    if self._completion is None or self._payloads:
+      terminal_metadata, code, message, termination = None, None, None, None
+    else:
+      terminal_metadata, code, message, termination = _explode_completion(
+          self._completion)
+      self._completion = None
+      action = True
+
+    if action:
+      ticket = links.Ticket(
+          self._operation_id, self._lowest_unused_sequence_number, None, None,
+          local_subscription, timeout, allowance, initial_metadata, payload,
+          terminal_metadata, code, message, termination, None)
+      self._lowest_unused_sequence_number += 1
+      return ticket
+    else:
+      return None
+
+  def _transmit(self, ticket):
+    """Commences the transmission loop sending tickets.
+
+    Args:
+      ticket: A links.Ticket to be sent to the other side of the operation.
+    """
+    def transmit(ticket):
+      while True:
+        transmission_outcome = callable_util.call_logging_exceptions(
+            self._ticket_sink, _TRANSMISSION_EXCEPTION_LOG_MESSAGE, ticket)
+        if transmission_outcome.exception is None:
+          with self._lock:
+            if ticket.termination is links.Ticket.Termination.COMPLETION:
+              self._termination_manager.transmission_complete()
+            ticket = self._next_ticket()
+            if ticket is None:
+              self._transmitting = False
+              return
+        else:
+          with self._lock:
+            if self._termination_manager.outcome is None:
+              self._termination_manager.abort(base.Outcome.TRANSMISSION_FAILURE)
+              self._expiration_manager.terminate()
+            return
+
+    self._pool.submit(callable_util.with_exceptions_logged(
+        transmit, _constants.INTERNAL_ERROR_LOG_MESSAGE), ticket)
+    self._transmitting = True
+
+  def kick_off(
+      self, group, method, timeout, initial_metadata, payload, completion,
+      allowance):
+    """See _interfaces.TransmissionManager.kickoff for specification."""
+    # TODO(nathaniel): Support other subscriptions.
+    subscription = links.Ticket.Subscription.FULL
+    terminal_metadata, code, message, termination = _explode_completion(
+        completion)
+    self._remote_allowance = 1 if payload is None else 0
+    ticket = links.Ticket(
+        self._operation_id, 0, group, method, subscription, timeout, allowance,
+        initial_metadata, payload, terminal_metadata, code, message,
+        termination, None)
+    self._lowest_unused_sequence_number = 1
+    self._transmit(ticket)
+
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """See _interfaces.TransmissionManager.advance for specification."""
+    effective_initial_metadata = initial_metadata
+    effective_payload = payload
+    effective_completion = completion
+    if allowance is not None and not self._remote_complete:
+      effective_allowance = allowance
+    else:
+      effective_allowance = None
+    if self._transmitting:
+      if effective_initial_metadata is not None:
+        self._initial_metadata = effective_initial_metadata
+      if effective_payload is not None:
+        self._payloads.append(effective_payload)
+      if effective_completion is not None:
+        self._completion = effective_completion
+      if effective_allowance is not None:
+        self._local_allowance += effective_allowance
+    else:
+      if effective_payload is not None:
+        if 0 < self._remote_allowance:
+          ticket_payload = effective_payload
+          self._remote_allowance -= 1
+        else:
+          self._payloads.append(effective_payload)
+          ticket_payload = None
+      else:
+        ticket_payload = None
+      if effective_completion is not None and not self._payloads:
+        ticket_completion = effective_completion
+      else:
+        self._completion = effective_completion
+        ticket_completion = None
+      if any(
+          (effective_initial_metadata, ticket_payload, ticket_completion,
+           effective_allowance)):
+        terminal_metadata, code, message, termination = _explode_completion(
+            completion)
+        ticket = links.Ticket(
+            self._operation_id, self._lowest_unused_sequence_number, None, None,
+            None, None, allowance, effective_initial_metadata, ticket_payload,
+            terminal_metadata, code, message, termination, None)
+        self._lowest_unused_sequence_number += 1
+        self._transmit(ticket)
+
+  def timeout(self, timeout):
+    """See _interfaces.TransmissionManager.timeout for specification."""
+    if self._transmitting:
+      self._timeout = timeout
+    else:
+      ticket = links.Ticket(
+          self._operation_id, self._lowest_unused_sequence_number, None, None,
+          None, timeout, None, None, None, None, None, None, None, None)
+      self._lowest_unused_sequence_number += 1
+      self._transmit(ticket)
+
+  def allowance(self, allowance):
+    """See _interfaces.TransmissionManager.allowance for specification."""
+    if self._transmitting or not self._payloads:
+      self._remote_allowance += allowance
+    else:
+      self._remote_allowance += allowance - 1
+      payload = self._payloads.pop(0)
+      if self._payloads:
+        completion = None
+      else:
+        completion = self._completion
+        self._completion = None
+      terminal_metadata, code, message, termination = _explode_completion(
+          completion)
+      ticket = links.Ticket(
+          self._operation_id, self._lowest_unused_sequence_number, None, None,
+          None, None, None, None, payload, terminal_metadata, code, message,
+          termination, None)
+      self._lowest_unused_sequence_number += 1
+      self._transmit(ticket)
+
+  def remote_complete(self):
+    """See _interfaces.TransmissionManager.remote_complete for specification."""
+    self._remote_complete = True
+    self._local_allowance = 0
+
+  def abort(self, outcome):
+    """See _interfaces.TransmissionManager.abort for specification."""
+    if self._transmitting:
+      self._aborted, self._abortion_outcome = True, outcome
+    else:
+      self._aborted = True
+      if outcome is not None:
+        termination = _constants.ABORTION_OUTCOME_TO_TICKET_TERMINATION[
+            outcome]
+        if termination is not None:
+          ticket = links.Ticket(
+              self._operation_id, self._lowest_unused_sequence_number, None,
+              None, None, None, None, None, None, None, None, None,
+              termination, None)
+          self._transmit(ticket)
diff --git a/src/ruby/bin/interop/test/cpp/interop/test_services.rb b/src/python/grpcio/grpc/framework/core/_utilities.py
index 5a3146c581..5b0d798751 100644
--- a/src/ruby/bin/interop/test/cpp/interop/test_services.rb
+++ b/src/python/grpcio/grpc/framework/core/_utilities.py
@@ -27,34 +27,20 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-# Generated by the protocol buffer compiler.  DO NOT EDIT!
-# Source: test/cpp/interop/test.proto for package 'grpc.testing'
+"""Package-internal utilities."""
 
-require 'grpc'
-require 'test/cpp/interop/test'
+import collections
 
-module Grpc
-  module Testing
-    module TestService
 
-      # TODO: add proto service documentation here
-      class Service
+class ServicerPackage(
+    collections.namedtuple(
+        'ServicerPackage', ('servicer', 'default_timeout', 'maximum_timeout'))):
+  """A trivial bundle class.
 
-        include GRPC::GenericService
-
-        self.marshal_class_method = :encode
-        self.unmarshal_class_method = :decode
-        self.service_name = 'grpc.testing.TestService'
-
-        rpc :EmptyCall, Empty, Empty
-        rpc :UnaryCall, SimpleRequest, SimpleResponse
-        rpc :StreamingOutputCall, StreamingOutputCallRequest, stream(StreamingOutputCallResponse)
-        rpc :StreamingInputCall, stream(StreamingInputCallRequest), StreamingInputCallResponse
-        rpc :FullDuplexCall, stream(StreamingOutputCallRequest), stream(StreamingOutputCallResponse)
-        rpc :HalfDuplexCall, stream(StreamingOutputCallRequest), stream(StreamingOutputCallResponse)
-      end
-
-      Stub = Service.rpc_stub_class
-    end
-  end
-end
+  Attributes:
+    servicer: A base.Servicer.
+    default_timeout: A float indicating the length of time in seconds to allow
+      for an operation invoked without a timeout.
+    maximum_timeout: A float indicating the maximum length of time in seconds to
+      allow for an operation.
+  """
diff --git a/src/python/grpcio/grpc/framework/core/implementations.py b/src/python/grpcio/grpc/framework/core/implementations.py
new file mode 100644
index 0000000000..364a7faed4
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/core/implementations.py
@@ -0,0 +1,62 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Entry points into the ticket-exchange-based base layer implementation."""
+
+# base and links are referenced from specification in this module.
+from grpc.framework.core import _end
+from grpc.framework.interfaces.base import base  # pylint: disable=unused-import
+from grpc.framework.interfaces.links import links  # pylint: disable=unused-import
+
+
+def invocation_end_link():
+  """Creates a base.End-links.Link suitable for operation invocation.
+
+  Returns:
+    An object that is both a base.End and a links.Link, that supports operation
+      invocation, and that translates operation invocation into ticket exchange.
+  """
+  return _end.serviceless_end_link()
+
+
+def service_end_link(servicer, default_timeout, maximum_timeout):
+  """Creates a base.End-links.Link suitable for operation service.
+
+  Args:
+    servicer: A base.Servicer for servicing operations.
+    default_timeout: A length of time in seconds to be used as the default
+      time alloted for a single operation.
+    maximum_timeout: A length of time in seconds to be used as the maximum
+      time alloted for a single operation.
+
+  Returns:
+    An object that is both a base.End and a links.Link and that services
+      operations that arrive at it through ticket exchange.
+  """
+  return _end.serviceful_end_link(servicer, default_timeout, maximum_timeout)
diff --git a/src/ruby/bin/interop/test/cpp/interop/empty.rb b/src/python/grpcio/grpc/framework/interfaces/base/__init__.py
index 3579fa5ded..7086519106 100644
--- a/src/ruby/bin/interop/test/cpp/interop/empty.rb
+++ b/src/python/grpcio/grpc/framework/interfaces/base/__init__.py
@@ -27,18 +27,4 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-# Generated by the protocol buffer compiler.  DO NOT EDIT!
-# source: test/cpp/interop/empty.proto
 
-require 'google/protobuf'
-
-Google::Protobuf::DescriptorPool.generated_pool.build do
-  add_message "grpc.testing.Empty" do
-  end
-end
-
-module Grpc
-  module Testing
-    Empty = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.Empty").msgclass
-  end
-end
diff --git a/src/python/grpcio/grpc/framework/interfaces/base/base.py b/src/python/grpcio/grpc/framework/interfaces/base/base.py
new file mode 100644
index 0000000000..76e0a5bdae
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/interfaces/base/base.py
@@ -0,0 +1,290 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""The base interface of RPC Framework.
+
+Implementations of this interface support the conduct of "operations":
+exchanges between two distinct ends of an arbitrary number of data payloads
+and metadata such as a name for the operation, initial and terminal metadata
+in each direction, and flow control. These operations may be used for transfers
+of data, remote procedure calls, status indication, or anything else
+applications choose.
+"""
+
+# threading is referenced from specification in this module.
+import abc
+import enum
+import threading
+
+# abandonment is referenced from specification in this module.
+from grpc.framework.foundation import abandonment  # pylint: disable=unused-import
+
+
+class NoSuchMethodError(Exception):
+  """Indicates that an unrecognized operation has been called."""
+
+
+@enum.unique
+class Outcome(enum.Enum):
+  """Operation outcomes."""
+
+  COMPLETED = 'completed'
+  CANCELLED = 'cancelled'
+  EXPIRED = 'expired'
+  LOCAL_SHUTDOWN = 'local shutdown'
+  REMOTE_SHUTDOWN = 'remote shutdown'
+  RECEPTION_FAILURE = 'reception failure'
+  TRANSMISSION_FAILURE = 'transmission failure'
+  LOCAL_FAILURE = 'local failure'
+  REMOTE_FAILURE = 'remote failure'
+
+
+class Completion(object):
+  """An aggregate of the values exchanged upon operation completion.
+
+  Attributes:
+    terminal_metadata: A terminal metadata value for the operaton.
+    code: A code value for the operation.
+    message: A message value for the operation.
+  """
+  __metaclass__ = abc.ABCMeta
+
+
+class OperationContext(object):
+  """Provides operation-related information and action."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def outcome(self):
+    """Indicates the operation's outcome (or that the operation is ongoing).
+
+    Returns:
+      None if the operation is still active or the Outcome value for the
+        operation if it has terminated.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def add_termination_callback(self, callback):
+    """Adds a function to be called upon operation termination.
+
+    Args:
+      callback: A callable to be passed an Outcome value on operation
+        termination.
+
+    Returns:
+      None if the operation has not yet terminated and the passed callback will
+        later be called when it does terminate, or if the operation has already
+        terminated an Outcome value describing the operation termination and the
+        passed callback will not be called as a result of this method call.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def time_remaining(self):
+    """Describes the length of allowed time remaining for the operation.
+
+    Returns:
+      A nonnegative float indicating the length of allowed time in seconds
+      remaining for the operation to complete before it is considered to have
+      timed out. Zero is returned if the operation has terminated.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def cancel(self):
+    """Cancels the operation if the operation has not yet terminated."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def fail(self, exception):
+    """Indicates that the operation has failed.
+
+    Args:
+      exception: An exception germane to the operation failure. May be None.
+    """
+    raise NotImplementedError()
+
+
+class Operator(object):
+  """An interface through which to participate in an operation."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    """Progresses the operation.
+
+    Args:
+      initial_metadata: An initial metadata value. Only one may ever be
+        communicated in each direction for an operation, and they must be
+        communicated no later than either the first payload or the completion.
+      payload: A payload value.
+      completion: A Completion value. May only ever be non-None once in either
+        direction, and no payloads may be passed after it has been communicated.
+      allowance: A positive integer communicating the number of additional
+        payloads allowed to be passed by the remote side of the operation.
+    """
+    raise NotImplementedError()
+
+
+class Subscription(object):
+  """Describes customer code's interest in values from the other side.
+
+  Attributes:
+    kind: A Kind value describing the overall kind of this value.
+    termination_callback: A callable to be passed the Outcome associated with
+      the operation after it has terminated. Must be non-None if kind is
+      Kind.TERMINATION_ONLY. Must be None otherwise.
+    allowance: A callable behavior that accepts positive integers representing
+      the number of additional payloads allowed to be passed to the other side
+      of the operation. Must be None if kind is Kind.FULL. Must not be None
+      otherwise.
+    operator: An Operator to be passed values from the other side of the
+      operation. Must be non-None if kind is Kind.FULL. Must be None otherwise.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+
+    NONE = 'none'
+    TERMINATION_ONLY = 'termination only'
+    FULL = 'full'
+
+
+class Servicer(object):
+  """Interface for service implementations."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def service(self, group, method, context, output_operator):
+    """Services an operation.
+
+    Args:
+      group: The group identifier of the operation to be serviced.
+      method: The method identifier of the operation to be serviced.
+      context: An OperationContext object affording contextual information and
+        actions.
+      output_operator: An Operator that will accept output values of the
+        operation.
+
+    Returns:
+      A Subscription via which this object may or may not accept more values of
+        the operation.
+
+    Raises:
+      NoSuchMethodError: If this Servicer does not handle operations with the
+        given group and method.
+      abandonment.Abandoned: If the operation has been aborted and there no
+        longer is any reason to service the operation.
+    """
+    raise NotImplementedError()
+
+
+class End(object):
+  """Common type for entry-point objects on both sides of an operation."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def start(self):
+    """Starts this object's service of operations."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stop(self, grace):
+    """Stops this object's service of operations.
+
+    This object will refuse service of new operations as soon as this method is
+    called but operations under way at the time of the call may be given a
+    grace period during which they are allowed to finish.
+
+    Args:
+      grace: A duration of time in seconds to allow ongoing operations to
+        terminate before being forcefully terminated by the stopping of this
+        End. May be zero to terminate all ongoing operations and immediately
+        stop.
+
+    Returns:
+      A threading.Event that will be set to indicate all operations having
+        terminated and this End having completely stopped. The returned event
+        may not be set until after the full grace period (if some ongoing
+        operation continues for the full length of the period) or it may be set
+        much sooner (if for example this End had no operations in progress at
+        the time its stop method was called).
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def operate(
+      self, group, method, subscription, timeout, initial_metadata=None,
+      payload=None, completion=None):
+    """Commences an operation.
+
+    Args:
+      group: The group identifier of the invoked operation.
+      method: The method identifier of the invoked operation.
+      subscription: A Subscription to which the results of the operation will be
+        passed.
+      timeout: A length of time in seconds to allow for the operation.
+      initial_metadata: An initial metadata value to be sent to the other side
+        of the operation. May be None if the initial metadata will be later
+        passed via the returned operator or if there will be no initial metadata
+        passed at all.
+      payload: An initial payload for the operation.
+      completion: A Completion value indicating the end of transmission to the
+        other side of the operation.
+
+    Returns:
+      A pair of objects affording information about the operation and action
+        continuing the operation. The first element of the returned pair is an
+        OperationContext for the operation and the second element of the
+        returned pair is an Operator to which operation values not passed in
+        this call should later be passed.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def operation_stats(self):
+    """Reports the number of terminated operations broken down by outcome.
+
+    Returns:
+      A dictionary from Outcome value to an integer identifying the number
+        of operations that terminated with that outcome.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def add_idle_action(self, action):
+    """Adds an action to be called when this End has no ongoing operations.
+
+    Args:
+      action: A callable that accepts no arguments.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio/grpc/framework/interfaces/base/utilities.py b/src/python/grpcio/grpc/framework/interfaces/base/utilities.py
new file mode 100644
index 0000000000..a9ee1a0981
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/interfaces/base/utilities.py
@@ -0,0 +1,79 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Utilities for use with the base interface of RPC Framework."""
+
+import collections
+
+from grpc.framework.interfaces.base import base
+
+
+class _Completion(
+    base.Completion,
+    collections.namedtuple(
+        '_Completion', ('terminal_metadata', 'code', 'message',))):
+  """A trivial implementation of base.Completion."""
+
+
+class _Subscription(
+    base.Subscription,
+    collections.namedtuple(
+        '_Subscription',
+        ('kind', 'termination_callback', 'allowance', 'operator',))):
+  """A trivial implementation of base.Subscription."""
+
+_NONE_SUBSCRIPTION = _Subscription(
+    base.Subscription.Kind.NONE, None, None, None)
+
+
+def completion(terminal_metadata, code, message):
+  """Creates a base.Completion aggregating the given operation values.
+
+  Args:
+    terminal_metadata: A terminal metadata value for an operaton.
+    code: A code value for an operation.
+    message: A message value for an operation.
+
+  Returns:
+    A base.Completion aggregating the given operation values.
+  """
+  return _Completion(terminal_metadata, code, message)
+
+
+def full_subscription(operator):
+  """Creates a "full" base.Subscription for the given base.Operator.
+
+  Args:
+    operator: A base.Operator to be used in an operation.
+
+  Returns:
+    A base.Subscription of kind base.Subscription.Kind.FULL wrapping the given
+      base.Operator.
+  """
+  return _Subscription(base.Subscription.Kind.FULL, None, None, operator)
diff --git a/src/python/grpcio/grpc/framework/interfaces/face/__init__.py b/src/python/grpcio/grpc/framework/interfaces/face/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/interfaces/face/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio/grpc/framework/interfaces/face/face.py b/src/python/grpcio/grpc/framework/interfaces/face/face.py
new file mode 100644
index 0000000000..948e7505b6
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/interfaces/face/face.py
@@ -0,0 +1,933 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Interfaces defining the Face layer of RPC Framework."""
+
+import abc
+import collections
+import enum
+
+# cardinality, style, abandonment, future, and stream are
+# referenced from specification in this module.
+from grpc.framework.common import cardinality  # pylint: disable=unused-import
+from grpc.framework.common import style  # pylint: disable=unused-import
+from grpc.framework.foundation import abandonment  # pylint: disable=unused-import
+from grpc.framework.foundation import future  # pylint: disable=unused-import
+from grpc.framework.foundation import stream  # pylint: disable=unused-import
+
+
+class NoSuchMethodError(Exception):
+  """Raised by customer code to indicate an unrecognized method.
+
+  Attributes:
+    group: The group of the unrecognized method.
+    name: The name of the unrecognized method.
+  """
+
+  def __init__(self, group, method):
+    """Constructor.
+
+    Args:
+      group: The group identifier of the unrecognized RPC name.
+      method: The method identifier of the unrecognized RPC name.
+    """
+    super(NoSuchMethodError, self).__init__()
+    self.group = group
+    self.method = method
+
+  def __repr__(self):
+    return 'face.NoSuchMethodError(%s, %s)' % (self.group, self.method,)
+
+
+class Abortion(
+    collections.namedtuple(
+        'Abortion',
+        ('kind', 'initial_metadata', 'terminal_metadata', 'code', 'details',))):
+  """A value describing RPC abortion.
+
+  Attributes:
+    kind: A Kind value identifying how the RPC failed.
+    initial_metadata: The initial metadata from the other side of the RPC or
+      None if no initial metadata value was received.
+    terminal_metadata: The terminal metadata from the other side of the RPC or
+      None if no terminal metadata value was received.
+    code: The code value from the other side of the RPC or None if no code value
+      was received.
+    details: The details value from the other side of the RPC or None if no
+      details value was received.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+    """Types of RPC abortion."""
+
+    CANCELLED = 'cancelled'
+    EXPIRED = 'expired'
+    LOCAL_SHUTDOWN = 'local shutdown'
+    REMOTE_SHUTDOWN = 'remote shutdown'
+    NETWORK_FAILURE = 'network failure'
+    LOCAL_FAILURE = 'local failure'
+    REMOTE_FAILURE = 'remote failure'
+
+
+class AbortionError(Exception):
+  """Common super type for exceptions indicating RPC abortion.
+
+    initial_metadata: The initial metadata from the other side of the RPC or
+      None if no initial metadata value was received.
+    terminal_metadata: The terminal metadata from the other side of the RPC or
+      None if no terminal metadata value was received.
+    code: The code value from the other side of the RPC or None if no code value
+      was received.
+    details: The details value from the other side of the RPC or None if no
+      details value was received.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  def __init__(self, initial_metadata, terminal_metadata, code, details):
+    super(AbortionError, self).__init__()
+    self.initial_metadata = initial_metadata
+    self.terminal_metadata = terminal_metadata
+    self.code = code
+    self.details = details
+
+
+class CancellationError(AbortionError):
+  """Indicates that an RPC has been cancelled."""
+
+
+class ExpirationError(AbortionError):
+  """Indicates that an RPC has expired ("timed out")."""
+
+
+class LocalShutdownError(AbortionError):
+  """Indicates that an RPC has terminated due to local shutdown of RPCs."""
+
+
+class RemoteShutdownError(AbortionError):
+  """Indicates that an RPC has terminated due to remote shutdown of RPCs."""
+
+
+class NetworkError(AbortionError):
+  """Indicates that some error occurred on the network."""
+
+
+class LocalError(AbortionError):
+  """Indicates that an RPC has terminated due to a local defect."""
+
+
+class RemoteError(AbortionError):
+  """Indicates that an RPC has terminated due to a remote defect."""
+
+
+class RpcContext(object):
+  """Provides RPC-related information and action."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def is_active(self):
+    """Describes whether the RPC is active or has terminated."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def time_remaining(self):
+    """Describes the length of allowed time remaining for the RPC.
+
+    Returns:
+      A nonnegative float indicating the length of allowed time in seconds
+      remaining for the RPC to complete before it is considered to have timed
+      out.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def add_abortion_callback(self, abortion_callback):
+    """Registers a callback to be called if the RPC is aborted.
+
+    Args:
+      abortion_callback: A callable to be called and passed an Abortion value
+        in the event of RPC abortion.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def cancel(self):
+    """Cancels the RPC.
+
+    Idempotent and has no effect if the RPC has already terminated.
+    """
+    raise NotImplementedError()
+
+
+class Call(RpcContext):
+  """Invocation-side utility object for an RPC."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def initial_metadata(self):
+    """Accesses the initial metadata from the service-side of the RPC.
+
+    This method blocks until the value is available or is known not to have been
+    emitted from the service-side of the RPC.
+
+    Returns:
+      The initial metadata object emitted by the service-side of the RPC, or
+        None if there was no such value.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminal_metadata(self):
+    """Accesses the terminal metadata from the service-side of the RPC.
+
+    This method blocks until the value is available or is known not to have been
+    emitted from the service-side of the RPC.
+
+    Returns:
+      The terminal metadata object emitted by the service-side of the RPC, or
+        None if there was no such value.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def code(self):
+    """Accesses the code emitted by the service-side of the RPC.
+
+    This method blocks until the value is available or is known not to have been
+    emitted from the service-side of the RPC.
+
+    Returns:
+      The code object emitted by the service-side of the RPC, or None if there
+        was no such value.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def details(self):
+    """Accesses the details value emitted by the service-side of the RPC.
+
+    This method blocks until the value is available or is known not to have been
+    emitted from the service-side of the RPC.
+
+    Returns:
+      The details value emitted by the service-side of the RPC, or None if there
+        was no such value.
+    """
+    raise NotImplementedError()
+
+
+class ServicerContext(RpcContext):
+  """A context object passed to method implementations."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def invocation_metadata(self):
+    """Accesses the metadata from the invocation-side of the RPC.
+
+    This method blocks until the value is available or is known not to have been
+    emitted from the invocation-side of the RPC.
+
+    Returns:
+      The metadata object emitted by the invocation-side of the RPC, or None if
+        there was no such value.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def initial_metadata(self, initial_metadata):
+    """Accepts the service-side initial metadata value of the RPC.
+
+    This method need not be called by method implementations if they have no
+    service-side initial metadata to transmit.
+
+    Args:
+      initial_metadata: The service-side initial metadata value of the RPC to
+        be transmitted to the invocation side of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminal_metadata(self, terminal_metadata):
+    """Accepts the service-side terminal metadata value of the RPC.
+
+    This method need not be called by method implementations if they have no
+    service-side terminal metadata to transmit.
+
+    Args:
+      terminal_metadata: The service-side terminal metadata value of the RPC to
+        be transmitted to the invocation side of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def code(self, code):
+    """Accepts the service-side code of the RPC.
+
+    This method need not be called by method implementations if they have no
+    code to transmit.
+
+    Args:
+      code: The code of the RPC to be transmitted to the invocation side of the
+        RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def details(self, details):
+    """Accepts the service-side details of the RPC.
+
+    This method need not be called by method implementations if they have no
+    service-side details to transmit.
+
+    Args:
+      details: The service-side details value of the RPC to be transmitted to
+        the invocation side of the RPC.
+    """
+    raise NotImplementedError()
+
+
+class ResponseReceiver(object):
+  """Invocation-side object used to accept the output of an RPC."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def initial_metadata(self, initial_metadata):
+    """Receives the initial metadata from the service-side of the RPC.
+
+    Args:
+      initial_metadata: The initial metadata object emitted from the
+        service-side of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def response(self, response):
+    """Receives a response from the service-side of the RPC.
+
+    Args:
+      response: A response object emitted from the service-side of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def complete(self, terminal_metadata, code, details):
+    """Receives the completion values emitted from the service-side of the RPC.
+
+    Args:
+      terminal_metadata: The terminal metadata object emitted from the
+        service-side of the RPC.
+      code: The code object emitted from the service-side of the RPC.
+      details: The details object emitted from the service-side of the RPC.
+    """
+    raise NotImplementedError()
+
+
+class UnaryUnaryMultiCallable(object):
+  """Affords invoking a unary-unary RPC in any call style."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __call__(
+      self, request, timeout, metadata=None, with_call=False):
+    """Synchronously invokes the underlying RPC.
+
+    Args:
+      request: The request value for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+      with_call: Whether or not to include return a Call for the RPC in addition
+        to the reponse.
+
+    Returns:
+      The response value for the RPC, and a Call for the RPC if with_call was
+        set to True at invocation.
+
+    Raises:
+      AbortionError: Indicating that the RPC was aborted.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def future(self, request, timeout, metadata=None):
+    """Asynchronously invokes the underlying RPC.
+
+    Args:
+      request: The request value for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and a future.Future. In the
+        event of RPC completion, the return Future's result value will be the
+        response value of the RPC. In the event of RPC abortion, the returned
+        Future's exception value will be an AbortionError.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event(
+      self, request, receiver, abortion_callback, timeout,
+      metadata=None):
+    """Asynchronously invokes the underlying RPC.
+
+    Args:
+      request: The request value for the RPC.
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      A Call for the RPC.
+    """
+    raise NotImplementedError()
+
+
+class UnaryStreamMultiCallable(object):
+  """Affords invoking a unary-stream RPC in any call style."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __call__(self, request, timeout, metadata=None):
+    """Invokes the underlying RPC.
+
+    Args:
+      request: The request value for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and an iterator of response
+        values. Drawing response values from the returned iterator may raise
+        AbortionError indicating abortion of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event(
+      self, request, receiver, abortion_callback, timeout,
+      metadata=None):
+    """Asynchronously invokes the underlying RPC.
+
+    Args:
+      request: The request value for the RPC.
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      A Call object for the RPC.
+    """
+    raise NotImplementedError()
+
+
+class StreamUnaryMultiCallable(object):
+  """Affords invoking a stream-unary RPC in any call style."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __call__(
+      self, request_iterator, timeout, metadata=None,
+      with_call=False):
+    """Synchronously invokes the underlying RPC.
+
+    Args:
+      request_iterator: An iterator that yields request values for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+      with_call: Whether or not to include return a Call for the RPC in addition
+        to the reponse.
+
+    Returns:
+      The response value for the RPC, and a Call for the RPC if with_call was
+        set to True at invocation.
+
+    Raises:
+      AbortionError: Indicating that the RPC was aborted.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def future(self, request_iterator, timeout, metadata=None):
+    """Asynchronously invokes the underlying RPC.
+
+    Args:
+      request_iterator: An iterator that yields request values for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and a future.Future. In the
+        event of RPC completion, the return Future's result value will be the
+        response value of the RPC. In the event of RPC abortion, the returned
+        Future's exception value will be an AbortionError.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event(
+      self, receiver, abortion_callback, timeout, metadata=None):
+    """Asynchronously invokes the underlying RPC.
+
+    Args:
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      A single object that is both a Call object for the RPC and a
+        stream.Consumer to which the request values of the RPC should be passed.
+    """
+    raise NotImplementedError()
+
+
+class StreamStreamMultiCallable(object):
+  """Affords invoking a stream-stream RPC in any call style."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __call__(self, request_iterator, timeout, metadata=None):
+    """Invokes the underlying RPC.
+
+    Args:
+      request_iterator: An iterator that yields request values for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and an iterator of response
+        values. Drawing response values from the returned iterator may raise
+        AbortionError indicating abortion of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event(
+      self, receiver, abortion_callback, timeout, metadata=None):
+    """Asynchronously invokes the underlying RPC.
+
+    Args:
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of
+        the RPC.
+
+    Returns:
+      A single object that is both a Call object for the RPC and a
+        stream.Consumer to which the request values of the RPC should be passed.
+    """
+    raise NotImplementedError()
+
+
+class MethodImplementation(object):
+  """A sum type that describes a method implementation.
+
+  Attributes:
+    cardinality: A cardinality.Cardinality value.
+    style: A style.Service value.
+    unary_unary_inline: The implementation of the method as a callable value
+      that takes a request value and a ServicerContext object and returns a
+      response value. Only non-None if cardinality is
+      cardinality.Cardinality.UNARY_UNARY and style is style.Service.INLINE.
+    unary_stream_inline: The implementation of the method as a callable value
+      that takes a request value and a ServicerContext object and returns an
+      iterator of response values. Only non-None if cardinality is
+      cardinality.Cardinality.UNARY_STREAM and style is style.Service.INLINE.
+    stream_unary_inline: The implementation of the method as a callable value
+      that takes an iterator of request values and a ServicerContext object and
+      returns a response value. Only non-None if cardinality is
+      cardinality.Cardinality.STREAM_UNARY and style is style.Service.INLINE.
+    stream_stream_inline: The implementation of the method as a callable value
+      that takes an iterator of request values and a ServicerContext object and
+      returns an iterator of response values. Only non-None if cardinality is
+      cardinality.Cardinality.STREAM_STREAM and style is style.Service.INLINE.
+    unary_unary_event: The implementation of the method as a callable value that
+      takes a request value, a response callback to which to pass the response
+      value of the RPC, and a ServicerContext. Only non-None if cardinality is
+      cardinality.Cardinality.UNARY_UNARY and style is style.Service.EVENT.
+    unary_stream_event: The implementation of the method as a callable value
+      that takes a request value, a stream.Consumer to which to pass the
+      response values of the RPC, and a ServicerContext. Only non-None if
+      cardinality is cardinality.Cardinality.UNARY_STREAM and style is
+      style.Service.EVENT.
+    stream_unary_event: The implementation of the method as a callable value
+      that takes a response callback to which to pass the response value of the
+      RPC and a ServicerContext and returns a stream.Consumer to which the
+      request values of the RPC should be passed. Only non-None if cardinality
+      is cardinality.Cardinality.STREAM_UNARY and style is style.Service.EVENT.
+    stream_stream_event: The implementation of the method as a callable value
+      that takes a stream.Consumer to which to pass the response values of the
+      RPC and a ServicerContext and returns a stream.Consumer to which the
+      request values of the RPC should be passed. Only non-None if cardinality
+      is cardinality.Cardinality.STREAM_STREAM and style is
+      style.Service.EVENT.
+  """
+  __metaclass__ = abc.ABCMeta
+
+
+class MultiMethodImplementation(object):
+  """A general type able to service many methods."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def service(self, group, method, response_consumer, context):
+    """Services an RPC.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      response_consumer: A stream.Consumer to be called to accept the response
+        values of the RPC.
+      context: a ServicerContext object.
+
+    Returns:
+      A stream.Consumer with which to accept the request values of the RPC. The
+        consumer returned from this method may or may not be invoked to
+        completion: in the case of RPC abortion, RPC Framework will simply stop
+        passing values to this object. Implementations must not assume that this
+        object will be called to completion of the request stream or even called
+        at all.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+      NoSuchMethodError: If this MultiMethod does not recognize the given group
+        and name for the RPC and is not able to service the RPC.
+    """
+    raise NotImplementedError()
+
+
+class GenericStub(object):
+  """Affords RPC invocation via generic methods."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def blocking_unary_unary(
+      self, group, method, request, timeout, metadata=None,
+      with_call=False):
+    """Invokes a unary-request-unary-response method.
+
+    This method blocks until either returning the response value of the RPC
+    (in the event of RPC completion) or raising an exception (in the event of
+    RPC abortion).
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request: The request value for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+      with_call: Whether or not to include return a Call for the RPC in addition
+        to the reponse.
+
+    Returns:
+      The response value for the RPC, and a Call for the RPC if with_call was
+        set to True at invocation.
+
+    Raises:
+      AbortionError: Indicating that the RPC was aborted.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def future_unary_unary(
+      self, group, method, request, timeout, metadata=None):
+    """Invokes a unary-request-unary-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request: The request value for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and a future.Future. In the
+        event of RPC completion, the return Future's result value will be the
+        response value of the RPC. In the event of RPC abortion, the returned
+        Future's exception value will be an AbortionError.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def inline_unary_stream(
+      self, group, method, request, timeout, metadata=None):
+    """Invokes a unary-request-stream-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request: The request value for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and an iterator of response
+        values. Drawing response values from the returned iterator may raise
+        AbortionError indicating abortion of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def blocking_stream_unary(
+      self, group, method, request_iterator, timeout, metadata=None,
+      with_call=False):
+    """Invokes a stream-request-unary-response method.
+
+    This method blocks until either returning the response value of the RPC
+    (in the event of RPC completion) or raising an exception (in the event of
+    RPC abortion).
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request_iterator: An iterator that yields request values for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+      with_call: Whether or not to include return a Call for the RPC in addition
+        to the reponse.
+
+    Returns:
+      The response value for the RPC, and a Call for the RPC if with_call was
+        set to True at invocation.
+
+    Raises:
+      AbortionError: Indicating that the RPC was aborted.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def future_stream_unary(
+      self, group, method, request_iterator, timeout, metadata=None):
+    """Invokes a stream-request-unary-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request_iterator: An iterator that yields request values for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and a future.Future. In the
+        event of RPC completion, the return Future's result value will be the
+        response value of the RPC. In the event of RPC abortion, the returned
+        Future's exception value will be an AbortionError.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def inline_stream_stream(
+      self, group, method, request_iterator, timeout, metadata=None):
+    """Invokes a stream-request-stream-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request_iterator: An iterator that yields request values for the RPC.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      An object that is both a Call for the RPC and an iterator of response
+        values. Drawing response values from the returned iterator may raise
+        AbortionError indicating abortion of the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event_unary_unary(
+      self, group, method, request, receiver, abortion_callback, timeout,
+      metadata=None):
+    """Event-driven invocation of a unary-request-unary-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request: The request value for the RPC.
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      A Call for the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event_unary_stream(
+      self, group, method, request, receiver, abortion_callback, timeout,
+      metadata=None):
+    """Event-driven invocation of a unary-request-stream-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      request: The request value for the RPC.
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      A Call for the RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event_stream_unary(
+      self, group, method, receiver, abortion_callback, timeout,
+      metadata=None):
+    """Event-driven invocation of a unary-request-unary-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      A pair of a Call object for the RPC and a stream.Consumer to which the
+        request values of the RPC should be passed.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event_stream_stream(
+      self, group, method, receiver, abortion_callback, timeout,
+      metadata=None):
+    """Event-driven invocation of a unary-request-stream-response method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+      receiver: A ResponseReceiver to be passed the response data of the RPC.
+      abortion_callback: A callback to be called and passed an Abortion value
+        in the event of RPC abortion.
+      timeout: A duration of time in seconds to allow for the RPC.
+      metadata: A metadata value to be passed to the service-side of the RPC.
+
+    Returns:
+      A pair of a Call object for the RPC and a stream.Consumer to which the
+        request values of the RPC should be passed.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def unary_unary(self, group, method):
+    """Creates a UnaryUnaryMultiCallable for a unary-unary method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+
+    Returns:
+      A UnaryUnaryMultiCallable value for the named unary-unary method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def unary_stream(self, group, method):
+    """Creates a UnaryStreamMultiCallable for a unary-stream method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+
+    Returns:
+      A UnaryStreamMultiCallable value for the name unary-stream method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stream_unary(self, group, method):
+    """Creates a StreamUnaryMultiCallable for a stream-unary method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+
+    Returns:
+      A StreamUnaryMultiCallable value for the named stream-unary method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stream_stream(self, group, method):
+    """Creates a StreamStreamMultiCallable for a stream-stream method.
+
+    Args:
+      group: The group identifier of the RPC.
+      method: The method identifier of the RPC.
+
+    Returns:
+      A StreamStreamMultiCallable value for the named stream-stream method.
+    """
+    raise NotImplementedError()
+
+
+class DynamicStub(object):
+  """Affords RPC invocation via attributes corresponding to afforded methods.
+
+  Instances of this type may be scoped to a single group so that attribute
+  access is unambiguous.
+
+  Instances of this type respond to attribute access as follows: if the
+  requested attribute is the name of a unary-unary method, the value of the
+  attribute will be a UnaryUnaryMultiCallable with which to invoke an RPC; if
+  the requested attribute is the name of a unary-stream method, the value of the
+  attribute will be a UnaryStreamMultiCallable with which to invoke an RPC; if
+  the requested attribute is the name of a stream-unary method, the value of the
+  attribute will be a StreamUnaryMultiCallable with which to invoke an RPC; and
+  if the requested attribute is the name of a stream-stream method, the value of
+  the attribute will be a StreamStreamMultiCallable with which to invoke an RPC.
+  """
+  __metaclass__ = abc.ABCMeta
diff --git a/src/python/grpcio/grpc/framework/interfaces/face/utilities.py b/src/python/grpcio/grpc/framework/interfaces/face/utilities.py
new file mode 100644
index 0000000000..db2ec6ed87
--- /dev/null
+++ b/src/python/grpcio/grpc/framework/interfaces/face/utilities.py
@@ -0,0 +1,178 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Utilities for RPC Framework's Face interface."""
+
+import collections
+
+# stream is referenced from specification in this module.
+from grpc.framework.common import cardinality
+from grpc.framework.common import style
+from grpc.framework.foundation import stream  # pylint: disable=unused-import
+from grpc.framework.interfaces.face import face
+
+
+class _MethodImplementation(
+    face.MethodImplementation,
+    collections.namedtuple(
+        '_MethodImplementation',
+        ['cardinality', 'style', 'unary_unary_inline', 'unary_stream_inline',
+         'stream_unary_inline', 'stream_stream_inline', 'unary_unary_event',
+         'unary_stream_event', 'stream_unary_event', 'stream_stream_event',])):
+  pass
+
+
+def unary_unary_inline(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a unary-unary RPC method as a callable value
+      that takes a request value and an face.ServicerContext object and
+      returns a response value.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.UNARY_UNARY, style.Service.INLINE, behavior,
+      None, None, None, None, None, None, None)
+
+
+def unary_stream_inline(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a unary-stream RPC method as a callable
+      value that takes a request value and an face.ServicerContext object and
+      returns an iterator of response values.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.UNARY_STREAM, style.Service.INLINE, None,
+      behavior, None, None, None, None, None, None)
+
+
+def stream_unary_inline(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a stream-unary RPC method as a callable
+      value that takes an iterator of request values and an
+      face.ServicerContext object and returns a response value.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.STREAM_UNARY, style.Service.INLINE, None, None,
+      behavior, None, None, None, None, None)
+
+
+def stream_stream_inline(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a stream-stream RPC method as a callable
+      value that takes an iterator of request values and an
+      face.ServicerContext object and returns an iterator of response values.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.STREAM_STREAM, style.Service.INLINE, None, None,
+      None, behavior, None, None, None, None)
+
+
+def unary_unary_event(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a unary-unary RPC method as a callable
+      value that takes a request value, a response callback to which to pass
+      the response value of the RPC, and an face.ServicerContext.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.UNARY_UNARY, style.Service.EVENT, None, None,
+      None, None, behavior, None, None, None)
+
+
+def unary_stream_event(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a unary-stream RPC method as a callable
+      value that takes a request value, a stream.Consumer to which to pass the
+      the response values of the RPC, and an face.ServicerContext.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.UNARY_STREAM, style.Service.EVENT, None, None,
+      None, None, None, behavior, None, None)
+
+
+def stream_unary_event(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a stream-unary RPC method as a callable
+      value that takes a response callback to which to pass the response value
+      of the RPC and an face.ServicerContext and returns a stream.Consumer to
+      which the request values of the RPC should be passed.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.STREAM_UNARY, style.Service.EVENT, None, None,
+      None, None, None, None, behavior, None)
+
+
+def stream_stream_event(behavior):
+  """Creates an face.MethodImplementation for the given behavior.
+
+  Args:
+    behavior: The implementation of a stream-stream RPC method as a callable
+      value that takes a stream.Consumer to which to pass the response values
+      of the RPC and an face.ServicerContext and returns a stream.Consumer to
+      which the request values of the RPC should be passed.
+
+  Returns:
+    An face.MethodImplementation derived from the given behavior.
+  """
+  return _MethodImplementation(
+      cardinality.Cardinality.STREAM_STREAM, style.Service.EVENT, None, None,
+      None, None, None, None, None, behavior)
diff --git a/src/python/grpcio/grpc/framework/interfaces/links/links.py b/src/python/grpcio/grpc/framework/interfaces/links/links.py
index 5ebbac8a6f..b98a30a399 100644
--- a/src/python/grpcio/grpc/framework/interfaces/links/links.py
+++ b/src/python/grpcio/grpc/framework/interfaces/links/links.py
@@ -34,12 +34,30 @@ import collections
 import enum
 
 
+class Transport(collections.namedtuple('Transport', ('kind', 'value',))):
+  """A sum type for handles to an underlying transport system.
+
+  Attributes:
+    kind: A Kind value identifying the kind of value being passed to or from
+      the underlying transport.
+    value: The value being passed through RPC Framework between the high-level
+      application and the underlying transport.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+    CALL_OPTION = 'call option'
+    SERVICER_CONTEXT = 'servicer context'
+    INVOCATION_CONTEXT = 'invocation context'
+
+
 class Ticket(
     collections.namedtuple(
         'Ticket',
-        ['operation_id', 'sequence_number', 'group', 'method', 'subscription',
+        ('operation_id', 'sequence_number', 'group', 'method', 'subscription',
          'timeout', 'allowance', 'initial_metadata', 'payload',
-         'terminal_metadata', 'code', 'message', 'termination'])):
+         'terminal_metadata', 'code', 'message', 'termination',
+         'transport',))):
   """A sum type for all values sent from a front to a back.
 
   Attributes:
@@ -81,6 +99,8 @@ class Ticket(
     termination: A Termination value describing the end of the operation, or
       None if the operation has not yet terminated. If set, no further tickets
       may be sent in the same direction.
+    transport: A Transport value or None, with further semantics being a matter
+      between high-level application and underlying transport.
   """
 
   @enum.unique
@@ -98,7 +118,7 @@ class Ticket(
     COMPLETION = 'completion'
     CANCELLATION = 'cancellation'
     EXPIRATION = 'expiration'
-    LOCAL_SHUTDOWN = 'local shutdown'
+    SHUTDOWN = 'shutdown'
     RECEPTION_FAILURE = 'reception failure'
     TRANSMISSION_FAILURE = 'transmission failure'
     LOCAL_FAILURE = 'local failure'
diff --git a/src/python/grpcio_test/grpc_test/_adapter/_links_test.py b/src/python/grpcio_test/grpc_test/_adapter/_links_test.py
index c4686b327a..4077b8e350 100644
--- a/src/python/grpcio_test/grpc_test/_adapter/_links_test.py
+++ b/src/python/grpcio_test/grpc_test/_adapter/_links_test.py
@@ -46,8 +46,8 @@ _TIMEOUT = 32
 # TODO(nathaniel): End-to-end metadata testing.
 def _transform_metadata(unused_metadata):
   return (
-      ('one unused key', 'one unused value'),
-      ('another unused key', 'another unused value'),
+      ('one_unused_key', 'one unused value'),
+      ('another_unused_key', 'another unused value'),
 )
 
 
diff --git a/src/python/grpcio_test/grpc_test/_adapter/_low_test.py b/src/python/grpcio_test/grpc_test/_adapter/_low_test.py
index 44fe760fbc..70149127da 100644
--- a/src/python/grpcio_test/grpc_test/_adapter/_low_test.py
+++ b/src/python/grpcio_test/grpc_test/_adapter/_low_test.py
@@ -52,7 +52,6 @@ def wait_for_events(completion_queues, deadline):
   def set_ith_result(i, completion_queue):
     result = completion_queue.next(deadline)
     with lock:
-      print i, completion_queue, result, time.time() - deadline
       results[i] = result
   for i, completion_queue in enumerate(completion_queues):
     thread = threading.Thread(target=set_ith_result,
@@ -80,10 +79,12 @@ class InsecureServerInsecureClient(unittest.TestCase):
     del self.client_channel
 
     self.client_completion_queue.shutdown()
-    while self.client_completion_queue.next().type != _types.EventType.QUEUE_SHUTDOWN:
+    while (self.client_completion_queue.next().type !=
+           _types.EventType.QUEUE_SHUTDOWN):
       pass
     self.server_completion_queue.shutdown()
-    while self.server_completion_queue.next().type != _types.EventType.QUEUE_SHUTDOWN:
+    while (self.server_completion_queue.next().type !=
+           _types.EventType.QUEUE_SHUTDOWN):
       pass
 
     del self.client_completion_queue
@@ -91,58 +92,68 @@ class InsecureServerInsecureClient(unittest.TestCase):
     del self.server
 
   def testEcho(self):
-    DEADLINE = time.time()+5
-    DEADLINE_TOLERANCE = 0.25
-    CLIENT_METADATA_ASCII_KEY = 'key'
-    CLIENT_METADATA_ASCII_VALUE = 'val'
-    CLIENT_METADATA_BIN_KEY = 'key-bin'
-    CLIENT_METADATA_BIN_VALUE = b'\0'*1000
-    SERVER_INITIAL_METADATA_KEY = 'init_me_me_me'
-    SERVER_INITIAL_METADATA_VALUE = 'whodawha?'
-    SERVER_TRAILING_METADATA_KEY = 'california_is_in_a_drought'
-    SERVER_TRAILING_METADATA_VALUE = 'zomg it is'
-    SERVER_STATUS_CODE = _types.StatusCode.OK
-    SERVER_STATUS_DETAILS = 'our work is never over'
-    REQUEST = 'in death a member of project mayhem has a name'
-    RESPONSE = 'his name is robert paulson'
-    METHOD = 'twinkies'
-    HOST = 'hostess'
+    deadline = time.time() + 5
+    event_time_tolerance = 2
+    deadline_tolerance = 0.25
+    client_metadata_ascii_key = 'key'
+    client_metadata_ascii_value = 'val'
+    client_metadata_bin_key = 'key-bin'
+    client_metadata_bin_value = b'\0'*1000
+    server_initial_metadata_key = 'init_me_me_me'
+    server_initial_metadata_value = 'whodawha?'
+    server_trailing_metadata_key = 'california_is_in_a_drought'
+    server_trailing_metadata_value = 'zomg it is'
+    server_status_code = _types.StatusCode.OK
+    server_status_details = 'our work is never over'
+    request = 'blarghaflargh'
+    response = 'his name is robert paulson'
+    method = 'twinkies'
+    host = 'hostess'
     server_request_tag = object()
-    request_call_result = self.server.request_call(self.server_completion_queue, server_request_tag)
+    request_call_result = self.server.request_call(self.server_completion_queue,
+                                                   server_request_tag)
 
-    self.assertEquals(_types.CallError.OK, request_call_result)
+    self.assertEqual(_types.CallError.OK, request_call_result)
 
     client_call_tag = object()
-    client_call = self.client_channel.create_call(self.client_completion_queue, METHOD, HOST, DEADLINE)
-    client_initial_metadata = [(CLIENT_METADATA_ASCII_KEY, CLIENT_METADATA_ASCII_VALUE), (CLIENT_METADATA_BIN_KEY, CLIENT_METADATA_BIN_VALUE)]
+    client_call = self.client_channel.create_call(
+        self.client_completion_queue, method, host, deadline)
+    client_initial_metadata = [
+        (client_metadata_ascii_key, client_metadata_ascii_value),
+        (client_metadata_bin_key, client_metadata_bin_value)
+    ]
     client_start_batch_result = client_call.start_batch([
         _types.OpArgs.send_initial_metadata(client_initial_metadata),
-        _types.OpArgs.send_message(REQUEST, 0),
+        _types.OpArgs.send_message(request, 0),
         _types.OpArgs.send_close_from_client(),
         _types.OpArgs.recv_initial_metadata(),
         _types.OpArgs.recv_message(),
         _types.OpArgs.recv_status_on_client()
     ], client_call_tag)
-    self.assertEquals(_types.CallError.OK, client_start_batch_result)
+    self.assertEqual(_types.CallError.OK, client_start_batch_result)
 
-    client_no_event, request_event, = wait_for_events([self.client_completion_queue, self.server_completion_queue], time.time() + 2)
-    self.assertEquals(client_no_event, None)
-    self.assertEquals(_types.EventType.OP_COMPLETE, request_event.type)
+    client_no_event, request_event, = wait_for_events(
+        [self.client_completion_queue, self.server_completion_queue],
+        time.time() + event_time_tolerance)
+    self.assertEqual(client_no_event, None)
+    self.assertEqual(_types.EventType.OP_COMPLETE, request_event.type)
     self.assertIsInstance(request_event.call, _low.Call)
     self.assertIs(server_request_tag, request_event.tag)
-    self.assertEquals(1, len(request_event.results))
+    self.assertEqual(1, len(request_event.results))
     received_initial_metadata = dict(request_event.results[0].initial_metadata)
     # Check that our metadata were transmitted
-    self.assertEquals(
+    self.assertEqual(
         dict(client_initial_metadata),
-        dict((x, received_initial_metadata[x]) for x in zip(*client_initial_metadata)[0]))
+        dict((x, received_initial_metadata[x])
+             for x in zip(*client_initial_metadata)[0]))
     # Check that Python's user agent string is a part of the full user agent
     # string
     self.assertIn('Python-gRPC-{}'.format(_grpcio_metadata.__version__),
                   received_initial_metadata['user-agent'])
-    self.assertEquals(METHOD, request_event.call_details.method)
-    self.assertEquals(HOST, request_event.call_details.host)
-    self.assertLess(abs(DEADLINE - request_event.call_details.deadline), DEADLINE_TOLERANCE)
+    self.assertEqual(method, request_event.call_details.method)
+    self.assertEqual(host, request_event.call_details.host)
+    self.assertLess(abs(deadline - request_event.call_details.deadline),
+                    deadline_tolerance)
 
     # Check that the channel is connected, and that both it and the call have
     # the proper target and peer; do this after the first flurry of messages to
@@ -155,33 +166,43 @@ class InsecureServerInsecureClient(unittest.TestCase):
 
     server_call_tag = object()
     server_call = request_event.call
-    server_initial_metadata = [(SERVER_INITIAL_METADATA_KEY, SERVER_INITIAL_METADATA_VALUE)]
-    server_trailing_metadata = [(SERVER_TRAILING_METADATA_KEY, SERVER_TRAILING_METADATA_VALUE)]
+    server_initial_metadata = [
+        (server_initial_metadata_key, server_initial_metadata_value)
+    ]
+    server_trailing_metadata = [
+        (server_trailing_metadata_key, server_trailing_metadata_value)
+    ]
     server_start_batch_result = server_call.start_batch([
         _types.OpArgs.send_initial_metadata(server_initial_metadata),
         _types.OpArgs.recv_message(),
-        _types.OpArgs.send_message(RESPONSE, 0),
+        _types.OpArgs.send_message(response, 0),
         _types.OpArgs.recv_close_on_server(),
-        _types.OpArgs.send_status_from_server(server_trailing_metadata, SERVER_STATUS_CODE, SERVER_STATUS_DETAILS)
+        _types.OpArgs.send_status_from_server(
+            server_trailing_metadata, server_status_code, server_status_details)
     ], server_call_tag)
-    self.assertEquals(_types.CallError.OK, server_start_batch_result)
+    self.assertEqual(_types.CallError.OK, server_start_batch_result)
 
-    client_event, server_event, = wait_for_events([self.client_completion_queue, self.server_completion_queue], time.time() + 1)
+    client_event, server_event, = wait_for_events(
+        [self.client_completion_queue, self.server_completion_queue],
+        time.time() + event_time_tolerance)
 
-    self.assertEquals(6, len(client_event.results))
+    self.assertEqual(6, len(client_event.results))
     found_client_op_types = set()
     for client_result in client_event.results:
-      self.assertNotIn(client_result.type, found_client_op_types)  # we expect each op type to be unique
+      # we expect each op type to be unique
+      self.assertNotIn(client_result.type, found_client_op_types)
       found_client_op_types.add(client_result.type)
       if client_result.type == _types.OpType.RECV_INITIAL_METADATA:
-        self.assertEquals(dict(server_initial_metadata), dict(client_result.initial_metadata))
+        self.assertEqual(dict(server_initial_metadata),
+                         dict(client_result.initial_metadata))
       elif client_result.type == _types.OpType.RECV_MESSAGE:
-        self.assertEquals(RESPONSE, client_result.message)
+        self.assertEqual(response, client_result.message)
       elif client_result.type == _types.OpType.RECV_STATUS_ON_CLIENT:
-        self.assertEquals(dict(server_trailing_metadata), dict(client_result.trailing_metadata))
-        self.assertEquals(SERVER_STATUS_DETAILS, client_result.status.details)
-        self.assertEquals(SERVER_STATUS_CODE, client_result.status.code)
-    self.assertEquals(set([
+        self.assertEqual(dict(server_trailing_metadata),
+                         dict(client_result.trailing_metadata))
+        self.assertEqual(server_status_details, client_result.status.details)
+        self.assertEqual(server_status_code, client_result.status.code)
+    self.assertEqual(set([
           _types.OpType.SEND_INITIAL_METADATA,
           _types.OpType.SEND_MESSAGE,
           _types.OpType.SEND_CLOSE_FROM_CLIENT,
@@ -190,16 +211,16 @@ class InsecureServerInsecureClient(unittest.TestCase):
           _types.OpType.RECV_STATUS_ON_CLIENT
       ]), found_client_op_types)
 
-    self.assertEquals(5, len(server_event.results))
+    self.assertEqual(5, len(server_event.results))
     found_server_op_types = set()
     for server_result in server_event.results:
       self.assertNotIn(client_result.type, found_server_op_types)
       found_server_op_types.add(server_result.type)
       if server_result.type == _types.OpType.RECV_MESSAGE:
-        self.assertEquals(REQUEST, server_result.message)
+        self.assertEqual(request, server_result.message)
       elif server_result.type == _types.OpType.RECV_CLOSE_ON_SERVER:
         self.assertFalse(server_result.cancelled)
-    self.assertEquals(set([
+    self.assertEqual(set([
           _types.OpType.SEND_INITIAL_METADATA,
           _types.OpType.RECV_MESSAGE,
           _types.OpType.SEND_MESSAGE,
@@ -211,5 +232,81 @@ class InsecureServerInsecureClient(unittest.TestCase):
     del server_call
 
 
+class HangingServerShutdown(unittest.TestCase):
+
+  def setUp(self):
+    self.server_completion_queue = _low.CompletionQueue()
+    self.server = _low.Server(self.server_completion_queue, [])
+    self.port = self.server.add_http2_port('[::]:0')
+    self.client_completion_queue = _low.CompletionQueue()
+    self.client_channel = _low.Channel('localhost:%d'%self.port, [])
+
+    self.server.start()
+
+  def tearDown(self):
+    self.server.shutdown()
+    del self.client_channel
+
+    self.client_completion_queue.shutdown()
+    self.server_completion_queue.shutdown()
+    while True:
+      client_event, server_event = wait_for_events(
+          [self.client_completion_queue, self.server_completion_queue],
+          float("+inf"))
+      if (client_event.type == _types.EventType.QUEUE_SHUTDOWN and
+          server_event.type == _types.EventType.QUEUE_SHUTDOWN):
+        break
+
+    del self.client_completion_queue
+    del self.server_completion_queue
+    del self.server
+
+  def testHangingServerCall(self):
+    deadline = time.time() + 5
+    deadline_tolerance = 0.25
+    event_time_tolerance = 2
+    cancel_all_calls_time_tolerance = 0.5
+    request = 'blarghaflargh'
+    method = 'twinkies'
+    host = 'hostess'
+    server_request_tag = object()
+    request_call_result = self.server.request_call(self.server_completion_queue,
+                                                   server_request_tag)
+
+    client_call_tag = object()
+    client_call = self.client_channel.create_call(self.client_completion_queue,
+                                                  method, host, deadline)
+    client_start_batch_result = client_call.start_batch([
+        _types.OpArgs.send_initial_metadata([]),
+        _types.OpArgs.send_message(request, 0),
+        _types.OpArgs.send_close_from_client(),
+        _types.OpArgs.recv_initial_metadata(),
+        _types.OpArgs.recv_message(),
+        _types.OpArgs.recv_status_on_client()
+    ], client_call_tag)
+
+    client_no_event, request_event, = wait_for_events(
+        [self.client_completion_queue, self.server_completion_queue],
+        time.time() + event_time_tolerance)
+
+    # Now try to shutdown the server and expect that we see server shutdown
+    # almost immediately after calling cancel_all_calls.
+    with self.assertRaises(RuntimeError):
+      self.server.cancel_all_calls()
+    shutdown_tag = object()
+    self.server.shutdown(shutdown_tag)
+    pre_cancel_timestamp = time.time()
+    self.server.cancel_all_calls()
+    finish_shutdown_timestamp = None
+    client_call_event, server_shutdown_event = wait_for_events(
+        [self.client_completion_queue, self.server_completion_queue],
+        time.time() + event_time_tolerance)
+    self.assertIs(shutdown_tag, server_shutdown_event.tag)
+    self.assertGreater(pre_cancel_timestamp + cancel_all_calls_time_tolerance,
+                       time.time())
+
+    del client_call
+
+
 if __name__ == '__main__':
   unittest.main(verbosity=2)
diff --git a/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py b/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py
new file mode 100644
index 0000000000..72b1ae5642
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py
@@ -0,0 +1,165 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests the RPC Framework Core's implementation of the Base interface."""
+
+import collections
+import logging
+import random
+import time
+import unittest
+
+from grpc._adapter import _intermediary_low
+from grpc._links import invocation
+from grpc._links import service
+from grpc.framework.core import implementations
+from grpc.framework.interfaces.base import utilities
+from grpc_test import test_common as grpc_test_common
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.interfaces.base import test_cases
+from grpc_test.framework.interfaces.base import test_interfaces
+
+_INVOCATION_INITIAL_METADATA = ((b'0', b'abc'), (b'1', b'def'), (b'2', b'ghi'),)
+_SERVICE_INITIAL_METADATA = ((b'3', b'jkl'), (b'4', b'mno'), (b'5', b'pqr'),)
+_SERVICE_TERMINAL_METADATA = ((b'6', b'stu'), (b'7', b'vwx'), (b'8', b'yza'),)
+_CODE = _intermediary_low.Code.OK
+_MESSAGE = b'test message'
+
+
+class _SerializationBehaviors(
+    collections.namedtuple(
+        '_SerializationBehaviors',
+        ('request_serializers', 'request_deserializers', 'response_serializers',
+         'response_deserializers',))):
+  pass
+
+
+class _Links(
+    collections.namedtuple(
+        '_Links',
+        ('invocation_end_link', 'invocation_grpc_link', 'service_grpc_link',
+         'service_end_link'))):
+  pass
+
+
+def _serialization_behaviors_from_serializations(serializations):
+  request_serializers = {}
+  request_deserializers = {}
+  response_serializers = {}
+  response_deserializers = {}
+  for (group, method), serialization in serializations.iteritems():
+    request_serializers[group, method] = serialization.serialize_request
+    request_deserializers[group, method] = serialization.deserialize_request
+    response_serializers[group, method] = serialization.serialize_response
+    response_deserializers[group, method] = serialization.deserialize_response
+  return _SerializationBehaviors(
+      request_serializers, request_deserializers, response_serializers,
+      response_deserializers)
+
+
+class _Implementation(test_interfaces.Implementation):
+
+  def instantiate(self, serializations, servicer):
+    serialization_behaviors = _serialization_behaviors_from_serializations(
+        serializations)
+    invocation_end_link = implementations.invocation_end_link()
+    service_end_link = implementations.service_end_link(
+        servicer, test_constants.DEFAULT_TIMEOUT,
+        test_constants.MAXIMUM_TIMEOUT)
+    service_grpc_link = service.service_link(
+        serialization_behaviors.request_deserializers,
+        serialization_behaviors.response_serializers)
+    port = service_grpc_link.add_port(0, None)
+    channel = _intermediary_low.Channel('localhost:%d' % port, None)
+    invocation_grpc_link = invocation.invocation_link(
+        channel, b'localhost',
+        serialization_behaviors.request_serializers,
+        serialization_behaviors.response_deserializers)
+
+    invocation_end_link.join_link(invocation_grpc_link)
+    invocation_grpc_link.join_link(invocation_end_link)
+    service_end_link.join_link(service_grpc_link)
+    service_grpc_link.join_link(service_end_link)
+    invocation_grpc_link.start()
+    service_grpc_link.start()
+    return invocation_end_link, service_end_link, (
+        invocation_grpc_link, service_grpc_link)
+
+  def destantiate(self, memo):
+    invocation_grpc_link, service_grpc_link = memo
+    invocation_grpc_link.stop()
+    service_grpc_link.stop_gracefully()
+
+  def invocation_initial_metadata(self):
+    return _INVOCATION_INITIAL_METADATA
+
+  def service_initial_metadata(self):
+    return _SERVICE_INITIAL_METADATA
+
+  def invocation_completion(self):
+    return utilities.completion(None, None, None)
+
+  def service_completion(self):
+    return utilities.completion(_SERVICE_TERMINAL_METADATA, _CODE, _MESSAGE)
+
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    return original_metadata is None or grpc_test_common.metadata_transmitted(
+        original_metadata, transmitted_metadata)
+
+  def completion_transmitted(self, original_completion, transmitted_completion):
+    if (original_completion.terminal_metadata is not None and
+        not grpc_test_common.metadata_transmitted(
+            original_completion.terminal_metadata,
+            transmitted_completion.terminal_metadata)):
+        return False
+    elif original_completion.code is not transmitted_completion.code:
+      return False
+    elif original_completion.message != transmitted_completion.message:
+      return False
+    else:
+      return True
+
+
+def setUpModule():
+  logging.warn('setUpModule!')
+
+
+def tearDownModule():
+  logging.warn('tearDownModule!')
+
+
+def load_tests(loader, tests, pattern):
+  return unittest.TestSuite(
+      tests=tuple(
+          loader.loadTestsFromTestCase(test_case_class)
+          for test_case_class in test_cases.test_cases(_Implementation())))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_test/grpc_test/_cython/adapter_low_test.py b/src/python/grpcio_test/grpc_test/_cython/adapter_low_test.py
index 9bab930e56..f1bec238cf 100644
--- a/src/python/grpcio_test/grpc_test/_cython/adapter_low_test.py
+++ b/src/python/grpcio_test/grpc_test/_cython/adapter_low_test.py
@@ -76,7 +76,7 @@ class InsecureServerInsecureClient(unittest.TestCase):
     CLIENT_METADATA_BIN_VALUE = b'\0'*1000
     SERVER_INITIAL_METADATA_KEY = 'init_me_me_me'
     SERVER_INITIAL_METADATA_VALUE = 'whodawha?'
-    SERVER_TRAILING_METADATA_KEY = 'California_is_in_a_drought'
+    SERVER_TRAILING_METADATA_KEY = 'california_is_in_a_drought'
     SERVER_TRAILING_METADATA_VALUE = 'zomg it is'
     SERVER_STATUS_CODE = _types.StatusCode.OK
     SERVER_STATUS_DETAILS = 'our work is never over'
diff --git a/src/python/grpcio_test/grpc_test/_links/_lonely_invocation_link_test.py b/src/python/grpcio_test/grpc_test/_links/_lonely_invocation_link_test.py
index abe240e07a..373a2b2a1f 100644
--- a/src/python/grpcio_test/grpc_test/_links/_lonely_invocation_link_test.py
+++ b/src/python/grpcio_test/grpc_test/_links/_lonely_invocation_link_test.py
@@ -66,7 +66,7 @@ class LonelyInvocationLinkTest(unittest.TestCase):
     ticket = links.Ticket(
         test_operation_id, 0, test_group, test_method,
         links.Ticket.Subscription.FULL, test_constants.SHORT_TIMEOUT, 1, None,
-        None, None, None, None, termination)
+        None, None, None, None, termination, None)
     invocation_link.accept_ticket(ticket)
     invocation_link_mate.block_until_tickets_satisfy(test_cases.terminated)
 
diff --git a/src/python/grpcio_test/grpc_test/_links/_transmission_test.py b/src/python/grpcio_test/grpc_test/_links/_transmission_test.py
index 9cdc9620f0..db011bca66 100644
--- a/src/python/grpcio_test/grpc_test/_links/_transmission_test.py
+++ b/src/python/grpcio_test/grpc_test/_links/_transmission_test.py
@@ -66,9 +66,9 @@ class TransmissionTest(test_cases.TransmissionTest, unittest.TestCase):
 
   def create_invocation_initial_metadata(self):
     return (
-        ('first invocation initial metadata key', 'just a string value'),
-        ('second invocation initial metadata key', '0123456789'),
-        ('third invocation initial metadata key-bin', '\x00\x57' * 100),
+        ('first_invocation_initial_metadata_key', 'just a string value'),
+        ('second_invocation_initial_metadata_key', '0123456789'),
+        ('third_invocation_initial_metadata_key-bin', '\x00\x57' * 100),
     )
 
   def create_invocation_terminal_metadata(self):
@@ -76,16 +76,16 @@ class TransmissionTest(test_cases.TransmissionTest, unittest.TestCase):
 
   def create_service_initial_metadata(self):
     return (
-        ('first service initial metadata key', 'just another string value'),
-        ('second service initial metadata key', '9876543210'),
-        ('third service initial metadata key-bin', '\x00\x59\x02' * 100),
+        ('first_service_initial_metadata_key', 'just another string value'),
+        ('second_service_initial_metadata_key', '9876543210'),
+        ('third_service_initial_metadata_key-bin', '\x00\x59\x02' * 100),
     )
 
   def create_service_terminal_metadata(self):
     return (
-        ('first service terminal metadata key', 'yet another string value'),
-        ('second service terminal metadata key', 'abcdefghij'),
-        ('third service terminal metadata key-bin', '\x00\x37' * 100),
+        ('first_service_terminal_metadata_key', 'yet another string value'),
+        ('second_service_terminal_metadata_key', 'abcdefghij'),
+        ('third_service_terminal_metadata_key-bin', '\x00\x37' * 100),
     )
 
   def create_invocation_completion(self):
@@ -128,14 +128,14 @@ class RoundTripTest(unittest.TestCase):
     invocation_ticket = links.Ticket(
         test_operation_id, 0, test_group, test_method,
         links.Ticket.Subscription.FULL, test_constants.LONG_TIMEOUT, None, None,
-        None, None, None, None, links.Ticket.Termination.COMPLETION)
+        None, None, None, None, links.Ticket.Termination.COMPLETION, None)
     invocation_link.accept_ticket(invocation_ticket)
     service_mate.block_until_tickets_satisfy(test_cases.terminated)
 
     service_ticket = links.Ticket(
         service_mate.tickets()[-1].operation_id, 0, None, None, None, None,
         None, None, None, None, test_code, test_message,
-        links.Ticket.Termination.COMPLETION)
+        links.Ticket.Termination.COMPLETION, None)
     service_link.accept_ticket(service_ticket)
     invocation_mate.block_until_tickets_satisfy(test_cases.terminated)
 
@@ -174,33 +174,34 @@ class RoundTripTest(unittest.TestCase):
     invocation_ticket = links.Ticket(
         test_operation_id, 0, test_group, test_method,
         links.Ticket.Subscription.FULL, test_constants.LONG_TIMEOUT, None, None,
-        None, None, None, None, None)
+        None, None, None, None, None, None)
     invocation_link.accept_ticket(invocation_ticket)
     requests = scenario.requests()
     for request_index, request in enumerate(requests):
       request_ticket = links.Ticket(
           test_operation_id, 1 + request_index, None, None, None, None, 1, None,
-          request, None, None, None, None)
+          request, None, None, None, None, None)
       invocation_link.accept_ticket(request_ticket)
       service_mate.block_until_tickets_satisfy(
           test_cases.at_least_n_payloads_received_predicate(1 + request_index))
       response_ticket = links.Ticket(
           service_mate.tickets()[0].operation_id, request_index, None, None,
           None, None, 1, None, scenario.response_for_request(request), None,
-          None, None, None)
+          None, None, None, None)
       service_link.accept_ticket(response_ticket)
       invocation_mate.block_until_tickets_satisfy(
           test_cases.at_least_n_payloads_received_predicate(1 + request_index))
     request_count = len(requests)
     invocation_completion_ticket = links.Ticket(
         test_operation_id, request_count + 1, None, None, None, None, None,
-        None, None, None, None, None, links.Ticket.Termination.COMPLETION)
+        None, None, None, None, None, links.Ticket.Termination.COMPLETION,
+        None)
     invocation_link.accept_ticket(invocation_completion_ticket)
     service_mate.block_until_tickets_satisfy(test_cases.terminated)
     service_completion_ticket = links.Ticket(
         service_mate.tickets()[0].operation_id, request_count, None, None, None,
         None, None, None, None, None, test_code, test_message,
-        links.Ticket.Termination.COMPLETION)
+        links.Ticket.Termination.COMPLETION, None)
     service_link.accept_ticket(service_completion_ticket)
     invocation_mate.block_until_tickets_satisfy(test_cases.terminated)
 
diff --git a/src/python/grpcio_test/grpc_test/framework/common/test_constants.py b/src/python/grpcio_test/grpc_test/framework/common/test_constants.py
index 3126d0d82c..e1d3c2709d 100644
--- a/src/python/grpcio_test/grpc_test/framework/common/test_constants.py
+++ b/src/python/grpcio_test/grpc_test/framework/common/test_constants.py
@@ -29,15 +29,25 @@
 
 """Constants shared among tests throughout RPC Framework."""
 
+# Value for maximum duration in seconds that a test is allowed for its actual
+# behavioral logic, excluding all time spent deliberately waiting in the test.
+TIME_ALLOWANCE = 10
 # Value for maximum duration in seconds of RPCs that may time out as part of a
 # test.
 SHORT_TIMEOUT = 4
 # Absurdly large value for maximum duration in seconds for should-not-time-out
 # RPCs made during tests.
 LONG_TIMEOUT = 3000
+# Values to supply on construction of an object that will service RPCs; these
+# should not be used as the actual timeout values of any RPCs made during tests.
+DEFAULT_TIMEOUT = 300
+MAXIMUM_TIMEOUT = 3600
 
 # The number of payloads to transmit in streaming tests.
 STREAM_LENGTH = 200
 
+# The size of payloads to transmit in tests.
+PAYLOAD_SIZE = 256 * 1024 + 17
+
 # The size of thread pools to use in tests.
 POOL_SIZE = 10
diff --git a/src/python/grpcio_test/grpc_test/framework/common/test_control.py b/src/python/grpcio_test/grpc_test/framework/common/test_control.py
index 3960c4e649..8d6eba5c2c 100644
--- a/src/python/grpcio_test/grpc_test/framework/common/test_control.py
+++ b/src/python/grpcio_test/grpc_test/framework/common/test_control.py
@@ -34,6 +34,14 @@ import contextlib
 import threading
 
 
+class Defect(Exception):
+  """Simulates a programming defect raised into in a system under test.
+
+  Use of a standard exception type is too easily misconstrued as an actual
+  defect in either the test infrastructure or the system under test.
+  """
+
+
 class Control(object):
   """An object that accepts program control from a system under test.
 
@@ -62,7 +70,7 @@ class PauseFailControl(Control):
   def control(self):
     with self._condition:
       if self._fail:
-        raise ValueError()
+        raise Defect()
 
       while self._paused:
         self._condition.wait()
diff --git a/src/python/grpcio_test/grpc_test/framework/core/__init__.py b/src/python/grpcio_test/grpc_test/framework/core/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/core/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio_test/grpc_test/framework/core/_base_interface_test.py b/src/python/grpcio_test/grpc_test/framework/core/_base_interface_test.py
new file mode 100644
index 0000000000..8d72f131d5
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/core/_base_interface_test.py
@@ -0,0 +1,96 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests the RPC Framework Core's implementation of the Base interface."""
+
+import logging
+import random
+import time
+import unittest
+
+from grpc.framework.core import implementations
+from grpc.framework.interfaces.base import utilities
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.interfaces.base import test_cases
+from grpc_test.framework.interfaces.base import test_interfaces
+
+
+class _Implementation(test_interfaces.Implementation):
+
+  def __init__(self):
+    self._invocation_initial_metadata = object()
+    self._service_initial_metadata = object()
+    self._invocation_terminal_metadata = object()
+    self._service_terminal_metadata = object()
+
+  def instantiate(self, serializations, servicer):
+    invocation = implementations.invocation_end_link()
+    service = implementations.service_end_link(
+        servicer, test_constants.DEFAULT_TIMEOUT,
+        test_constants.MAXIMUM_TIMEOUT)
+    invocation.join_link(service)
+    service.join_link(invocation)
+    return invocation, service, None
+
+  def destantiate(self, memo):
+    pass
+
+  def invocation_initial_metadata(self):
+    return self._invocation_initial_metadata
+
+  def service_initial_metadata(self):
+    return self._service_initial_metadata
+
+  def invocation_completion(self):
+    return utilities.completion(self._invocation_terminal_metadata, None, None)
+
+  def service_completion(self):
+    return utilities.completion(self._service_terminal_metadata, None, None)
+
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    return transmitted_metadata is original_metadata
+
+  def completion_transmitted(self, original_completion, transmitted_completion):
+    return (
+        (original_completion.terminal_metadata is
+         transmitted_completion.terminal_metadata) and
+        original_completion.code is transmitted_completion.code and
+        original_completion.message is transmitted_completion.message
+    )
+
+
+def load_tests(loader, tests, pattern):
+  return unittest.TestSuite(
+      tests=tuple(
+          loader.loadTestsFromTestCase(test_case_class)
+          for test_case_class in test_cases.test_cases(_Implementation())))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/base/__init__.py b/src/python/grpcio_test/grpc_test/framework/interfaces/base/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/base/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/base/_control.py b/src/python/grpcio_test/grpc_test/framework/interfaces/base/_control.py
new file mode 100644
index 0000000000..e4d2a7a0d7
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/base/_control.py
@@ -0,0 +1,568 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Part of the tests of the base interface of RPC Framework."""
+
+import abc
+import collections
+import enum
+import random  # pylint: disable=unused-import
+import threading
+import time
+
+from grpc.framework.interfaces.base import base
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.interfaces.base import _sequence
+from grpc_test.framework.interfaces.base import _state
+from grpc_test.framework.interfaces.base import test_interfaces  # pylint: disable=unused-import
+
+_GROUP = 'base test cases test group'
+_METHOD = 'base test cases test method'
+
+_PAYLOAD_RANDOM_SECTION_MAXIMUM_SIZE = test_constants.PAYLOAD_SIZE / 20
+_MINIMUM_PAYLOAD_SIZE = test_constants.PAYLOAD_SIZE / 600
+
+
+def _create_payload(randomness):
+  length = randomness.randint(
+      _MINIMUM_PAYLOAD_SIZE, test_constants.PAYLOAD_SIZE)
+  random_section_length = randomness.randint(
+      0, min(_PAYLOAD_RANDOM_SECTION_MAXIMUM_SIZE, length))
+  random_section = bytes(
+      bytearray(
+          randomness.getrandbits(8) for _ in range(random_section_length)))
+  sevens_section = '\x07' * (length - random_section_length)
+  return b''.join(randomness.sample((random_section, sevens_section), 2))
+
+
+def _anything_in_flight(state):
+  return (
+      state.invocation_initial_metadata_in_flight is not None or
+      state.invocation_payloads_in_flight or
+      state.invocation_completion_in_flight is not None or
+      state.service_initial_metadata_in_flight is not None or
+      state.service_payloads_in_flight or
+      state.service_completion_in_flight is not None or
+      0 < state.invocation_allowance_in_flight or
+      0 < state.service_allowance_in_flight
+  )
+
+
+def _verify_service_advance_and_update_state(
+    initial_metadata, payload, completion, allowance, state, implementation):
+  if initial_metadata is not None:
+    if state.invocation_initial_metadata_received:
+      return 'Later invocation initial metadata received: %s' % (
+          initial_metadata,)
+    if state.invocation_payloads_received:
+      return 'Invocation initial metadata received after payloads: %s' % (
+          state.invocation_payloads_received)
+    if state.invocation_completion_received:
+      return 'Invocation initial metadata received after invocation completion!'
+    if not implementation.metadata_transmitted(
+        state.invocation_initial_metadata_in_flight, initial_metadata):
+      return 'Invocation initial metadata maltransmitted: %s, %s' % (
+          state.invocation_initial_metadata_in_flight, initial_metadata)
+    else:
+      state.invocation_initial_metadata_in_flight = None
+      state.invocation_initial_metadata_received = True
+
+  if payload is not None:
+    if state.invocation_completion_received:
+      return 'Invocation payload received after invocation completion!'
+    elif not state.invocation_payloads_in_flight:
+      return 'Invocation payload "%s" received but not in flight!' % (payload,)
+    elif state.invocation_payloads_in_flight[0] != payload:
+      return 'Invocation payload mismatch: %s, %s' % (
+          state.invocation_payloads_in_flight[0], payload)
+    elif state.service_side_invocation_allowance < 1:
+      return 'Disallowed invocation payload!'
+    else:
+      state.invocation_payloads_in_flight.pop(0)
+      state.invocation_payloads_received += 1
+      state.service_side_invocation_allowance -= 1
+
+  if completion is not None:
+    if state.invocation_completion_received:
+      return 'Later invocation completion received: %s' % (completion,)
+    elif not implementation.completion_transmitted(
+        state.invocation_completion_in_flight, completion):
+      return 'Invocation completion maltransmitted: %s, %s' % (
+          state.invocation_completion_in_flight, completion)
+    else:
+      state.invocation_completion_in_flight = None
+      state.invocation_completion_received = True
+
+  if allowance is not None:
+    if allowance <= 0:
+      return 'Illegal allowance value: %s' % (allowance,)
+    else:
+      state.service_allowance_in_flight -= allowance
+      state.service_side_service_allowance += allowance
+
+
+def _verify_invocation_advance_and_update_state(
+    initial_metadata, payload, completion, allowance, state, implementation):
+  if initial_metadata is not None:
+    if state.service_initial_metadata_received:
+      return 'Later service initial metadata received: %s' % (initial_metadata,)
+    if state.service_payloads_received:
+      return 'Service initial metadata received after service payloads: %s' % (
+          state.service_payloads_received)
+    if state.service_completion_received:
+      return 'Service initial metadata received after service completion!'
+    if not implementation.metadata_transmitted(
+        state.service_initial_metadata_in_flight, initial_metadata):
+      return 'Service initial metadata maltransmitted: %s, %s' % (
+          state.service_initial_metadata_in_flight, initial_metadata)
+    else:
+      state.service_initial_metadata_in_flight = None
+      state.service_initial_metadata_received = True
+
+  if payload is not None:
+    if state.service_completion_received:
+      return 'Service payload received after service completion!'
+    elif not state.service_payloads_in_flight:
+      return 'Service payload "%s" received but not in flight!' % (payload,)
+    elif state.service_payloads_in_flight[0] != payload:
+      return 'Service payload mismatch: %s, %s' % (
+          state.invocation_payloads_in_flight[0], payload)
+    elif state.invocation_side_service_allowance < 1:
+      return 'Disallowed service payload!'
+    else:
+      state.service_payloads_in_flight.pop(0)
+      state.service_payloads_received += 1
+      state.invocation_side_service_allowance -= 1
+
+  if completion is not None:
+    if state.service_completion_received:
+      return 'Later service completion received: %s' % (completion,)
+    elif not implementation.completion_transmitted(
+        state.service_completion_in_flight, completion):
+      return 'Service completion maltransmitted: %s, %s' % (
+          state.service_completion_in_flight, completion)
+    else:
+      state.service_completion_in_flight = None
+      state.service_completion_received = True
+
+  if allowance is not None:
+    if allowance <= 0:
+      return 'Illegal allowance value: %s' % (allowance,)
+    else:
+      state.invocation_allowance_in_flight -= allowance
+      state.invocation_side_service_allowance += allowance
+
+
+class Invocation(
+    collections.namedtuple(
+        'Invocation',
+        ('group', 'method', 'subscription_kind', 'timeout', 'initial_metadata',
+         'payload', 'completion',))):
+  """A description of operation invocation.
+
+  Attributes:
+    group: The group identifier for the operation.
+    method: The method identifier for the operation.
+    subscription_kind: A base.Subscription.Kind value describing the kind of
+      subscription to use for the operation.
+    timeout: A duration in seconds to pass as the timeout value for the
+      operation.
+    initial_metadata: An object to pass as the initial metadata for the
+      operation or None.
+    payload: An object to pass as a payload value for the operation or None.
+    completion: An object to pass as a completion value for the operation or
+      None.
+  """
+
+
+class OnAdvance(
+    collections.namedtuple(
+        'OnAdvance',
+        ('kind', 'initial_metadata', 'payload', 'completion', 'allowance'))):
+  """Describes action to be taken in a test in response to an advance call.
+
+  Attributes:
+    kind: A Kind value describing the overall kind of response.
+    initial_metadata: An initial metadata value to pass to a call of the advance
+      method of the operator under test. Only valid if kind is Kind.ADVANCE and
+      may be None.
+    payload: A payload value to pass to a call of the advance method of the
+      operator under test. Only valid if kind is Kind.ADVANCE and may be None.
+    completion: A base.Completion value to pass to a call of the advance method
+      of the operator under test. Only valid if kind is Kind.ADVANCE and may be
+      None.
+    allowance: An allowance value to pass to a call of the advance method of the
+      operator under test. Only valid if kind is Kind.ADVANCE and may be None.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+    ADVANCE = 'advance'
+    DEFECT = 'defect'
+    IDLE = 'idle'
+
+
+_DEFECT_ON_ADVANCE = OnAdvance(OnAdvance.Kind.DEFECT, None, None, None, None)
+_IDLE_ON_ADVANCE = OnAdvance(OnAdvance.Kind.IDLE, None, None, None, None)
+
+
+class Instruction(
+    collections.namedtuple(
+        'Instruction',
+        ('kind', 'advance_args', 'advance_kwargs', 'conclude_success',
+         'conclude_message', 'conclude_invocation_outcome',
+         'conclude_service_outcome',))):
+  """"""
+
+  @enum.unique
+  class Kind(enum.Enum):
+    ADVANCE = 'ADVANCE'
+    CANCEL = 'CANCEL'
+    CONCLUDE = 'CONCLUDE'
+
+
+class Controller(object):
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def failed(self, message):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_request(self, request):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_request(self, serialized_request):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_response(self, response):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_response(self, serialized_response):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation(self):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def poll(self):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def on_service_advance(
+      self, initial_metadata, payload, completion, allowance):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def on_invocation_advance(
+      self, initial_metadata, payload, completion, allowance):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def service_on_termination(self, outcome):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_on_termination(self, outcome):
+    """"""
+    raise NotImplementedError()
+
+
+class ControllerCreator(object):
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def name(self):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def controller(self, implementation, randomness):
+    """"""
+    raise NotImplementedError()
+
+
+class _Remainder(
+    collections.namedtuple(
+        '_Remainder',
+        ('invocation_payloads', 'service_payloads', 'invocation_completion',
+         'service_completion',))):
+  """Describes work remaining to be done in a portion of a test.
+
+  Attributes:
+    invocation_payloads: The number of payloads to be sent from the invocation
+      side of the operation to the service side of the operation.
+    service_payloads: The number of payloads to be sent from the service side of
+      the operation to the invocation side of the operation.
+    invocation_completion: Whether or not completion from the invocation side of
+      the operation should be indicated and has yet to be indicated.
+    service_completion: Whether or not completion from the service side of the
+      operation should be indicated and has yet to be indicated.
+  """
+
+
+class _SequenceController(Controller):
+
+  def __init__(self, sequence, implementation, randomness):
+    """Constructor.
+
+    Args:
+      sequence: A _sequence.Sequence describing the steps to be taken in the
+        test at a relatively high level.
+      implementation: A test_interfaces.Implementation encapsulating the
+        base interface implementation that is the system under test.
+      randomness: A random.Random instance for use in the test.
+    """
+    self._condition = threading.Condition()
+    self._sequence = sequence
+    self._implementation = implementation
+    self._randomness = randomness
+
+    self._until = None
+    self._remaining_elements = None
+    self._poll_next = None
+    self._message = None
+
+    self._state = _state.OperationState()
+    self._todo = None
+
+  # called with self._condition
+  def _failed(self, message):
+    self._message = message
+    self._condition.notify_all()
+
+  def _passed(self, invocation_outcome, service_outcome):
+    self._poll_next = Instruction(
+        Instruction.Kind.CONCLUDE, None, None, True, None, invocation_outcome,
+        service_outcome)
+    self._condition.notify_all()
+
+  def failed(self, message):
+    with self._condition:
+      self._failed(message)
+
+  def serialize_request(self, request):
+    return request + request
+
+  def deserialize_request(self, serialized_request):
+    return serialized_request[:len(serialized_request) / 2]
+
+  def serialize_response(self, response):
+    return response * 3
+
+  def deserialize_response(self, serialized_response):
+    return serialized_response[2 * len(serialized_response) / 3:]
+
+  def invocation(self):
+    with self._condition:
+      self._until = time.time() + self._sequence.maximum_duration
+      self._remaining_elements = list(self._sequence.elements)
+      if self._sequence.invocation.initial_metadata:
+        initial_metadata = self._implementation.invocation_initial_metadata()
+        self._state.invocation_initial_metadata_in_flight = initial_metadata
+      else:
+        initial_metadata = None
+      if self._sequence.invocation.payload:
+        payload = _create_payload(self._randomness)
+        self._state.invocation_payloads_in_flight.append(payload)
+      else:
+        payload = None
+      if self._sequence.invocation.complete:
+        completion = self._implementation.invocation_completion()
+        self._state.invocation_completion_in_flight = completion
+      else:
+        completion = None
+      return Invocation(
+          _GROUP, _METHOD, base.Subscription.Kind.FULL,
+          self._sequence.invocation.timeout, initial_metadata, payload,
+          completion)
+
+  def poll(self):
+    with self._condition:
+      while True:
+        if self._message is not None:
+          return Instruction(
+              Instruction.Kind.CONCLUDE, None, None, False, self._message, None,
+              None)
+        elif self._poll_next:
+          poll_next = self._poll_next
+          self._poll_next = None
+          return poll_next
+        elif self._until < time.time():
+          return Instruction(
+              Instruction.Kind.CONCLUDE, None, None, False,
+              'overran allotted time!', None, None)
+        else:
+          self._condition.wait(timeout=self._until-time.time())
+
+  def on_service_advance(
+      self, initial_metadata, payload, completion, allowance):
+    with self._condition:
+      message = _verify_service_advance_and_update_state(
+          initial_metadata, payload, completion, allowance, self._state,
+          self._implementation)
+      if message is not None:
+        self._failed(message)
+      if self._todo is not None:
+        raise ValueError('TODO!!!')
+      elif _anything_in_flight(self._state):
+        return _IDLE_ON_ADVANCE
+      elif self._remaining_elements:
+        element = self._remaining_elements.pop(0)
+        if element.kind is _sequence.Element.Kind.SERVICE_TRANSMISSION:
+          if element.transmission.initial_metadata:
+            initial_metadata = self._implementation.service_initial_metadata()
+            self._state.service_initial_metadata_in_flight = initial_metadata
+          else:
+            initial_metadata = None
+          if element.transmission.payload:
+            payload = _create_payload(self._randomness)
+            self._state.service_payloads_in_flight.append(payload)
+            self._state.service_side_service_allowance -= 1
+          else:
+            payload = None
+          if element.transmission.complete:
+            completion = self._implementation.service_completion()
+            self._state.service_completion_in_flight = completion
+          else:
+            completion = None
+          if (not self._state.invocation_completion_received and
+              0 <= self._state.service_side_invocation_allowance):
+            allowance = 1
+            self._state.service_side_invocation_allowance += 1
+            self._state.invocation_allowance_in_flight += 1
+          else:
+            allowance = None
+          return OnAdvance(
+              OnAdvance.Kind.ADVANCE, initial_metadata, payload, completion,
+              allowance)
+        else:
+          raise ValueError('TODO!!!')
+      else:
+        return _IDLE_ON_ADVANCE
+
+  def on_invocation_advance(
+      self, initial_metadata, payload, completion, allowance):
+    with self._condition:
+      message = _verify_invocation_advance_and_update_state(
+          initial_metadata, payload, completion, allowance, self._state,
+          self._implementation)
+      if message is not None:
+        self._failed(message)
+      if self._todo is not None:
+        raise ValueError('TODO!!!')
+      elif _anything_in_flight(self._state):
+        return _IDLE_ON_ADVANCE
+      elif self._remaining_elements:
+        element = self._remaining_elements.pop(0)
+        if element.kind is _sequence.Element.Kind.INVOCATION_TRANSMISSION:
+          if element.transmission.initial_metadata:
+            initial_metadata = self._implementation.invocation_initial_metadata()
+            self._state.invocation_initial_metadata_in_fight = initial_metadata
+          else:
+            initial_metadata = None
+          if element.transmission.payload:
+            payload = _create_payload(self._randomness)
+            self._state.invocation_payloads_in_flight.append(payload)
+            self._state.invocation_side_invocation_allowance -= 1
+          else:
+            payload = None
+          if element.transmission.complete:
+            completion = self._implementation.invocation_completion()
+            self._state.invocation_completion_in_flight = completion
+          else:
+            completion = None
+          if (not self._state.service_completion_received and
+              0 <= self._state.invocation_side_service_allowance):
+            allowance = 1
+            self._state.invocation_side_service_allowance += 1
+            self._state.service_allowance_in_flight += 1
+          else:
+            allowance = None
+          return OnAdvance(
+              OnAdvance.Kind.ADVANCE, initial_metadata, payload, completion,
+              allowance)
+        else:
+          raise ValueError('TODO!!!')
+      else:
+        return _IDLE_ON_ADVANCE
+
+  def service_on_termination(self, outcome):
+    with self._condition:
+      self._state.service_side_outcome = outcome
+      if self._todo is not None or self._remaining_elements:
+        self._failed('Premature service-side outcome %s!' % (outcome,))
+      elif outcome is not self._sequence.outcome.service:
+        self._failed(
+            'Incorrect service-side outcome: %s should have been %s' % (
+                outcome, self._sequence.outcome.service))
+      elif self._state.invocation_side_outcome is not None:
+        self._passed(self._state.invocation_side_outcome, outcome)
+
+  def invocation_on_termination(self, outcome):
+    with self._condition:
+      self._state.invocation_side_outcome = outcome
+      if self._todo is not None or self._remaining_elements:
+        self._failed('Premature invocation-side outcome %s!' % (outcome,))
+      elif outcome is not self._sequence.outcome.invocation:
+        self._failed(
+            'Incorrect invocation-side outcome: %s should have been %s' % (
+                outcome, self._sequence.outcome.invocation))
+      elif self._state.service_side_outcome is not None:
+        self._passed(outcome, self._state.service_side_outcome)
+
+
+class _SequenceControllerCreator(ControllerCreator):
+
+  def __init__(self, sequence):
+    self._sequence = sequence
+
+  def name(self):
+    return self._sequence.name
+
+  def controller(self, implementation, randomness):
+    return _SequenceController(self._sequence, implementation, randomness)
+
+
+CONTROLLER_CREATORS = tuple(
+    _SequenceControllerCreator(sequence) for sequence in _sequence.SEQUENCES)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/base/_sequence.py b/src/python/grpcio_test/grpc_test/framework/interfaces/base/_sequence.py
new file mode 100644
index 0000000000..1d77aaebe6
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/base/_sequence.py
@@ -0,0 +1,168 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Part of the tests of the base interface of RPC Framework."""
+
+import collections
+import enum
+
+from grpc.framework.interfaces.base import base
+from grpc_test.framework.common import test_constants
+
+
+class Invocation(
+    collections.namedtuple(
+        'Invocation', ('timeout', 'initial_metadata', 'payload', 'complete',))):
+  """A recipe for operation invocation.
+
+  Attributes:
+    timeout: A duration in seconds to pass to the system under test as the
+      operation's timeout value.
+    initial_metadata: A boolean indicating whether or not to pass initial
+      metadata when invoking the operation.
+    payload: A boolean indicating whether or not to pass a payload when
+      invoking the operation.
+    complete: A boolean indicating whether or not to indicate completion of
+      transmissions from the invoking side of the operation when invoking the
+      operation.
+  """
+
+
+class Transmission(
+    collections.namedtuple(
+        'Transmission', ('initial_metadata', 'payload', 'complete',))):
+  """A recipe for a single transmission in an operation.
+
+  Attributes:
+    initial_metadata: A boolean indicating whether or not to pass initial
+      metadata as part of the transmission.
+    payload: A boolean indicating whether or not to pass a payload as part of
+      the transmission.
+    complete: A boolean indicating whether or not to indicate completion of
+      transmission from the transmitting side of the operation as part of the
+      transmission.
+  """
+
+
+class Intertransmission(
+    collections.namedtuple('Intertransmission', ('invocation', 'service',))):
+  """A recipe for multiple transmissions in an operation.
+
+  Attributes:
+    invocation: An integer describing the number of payloads to send from the
+      invocation side of the operation to the service side.
+    service: An integer describing the number of payloads to send from the
+      service side of the operation to the invocation side.
+  """
+
+
+class Element(collections.namedtuple('Element', ('kind', 'transmission',))):
+  """A sum type for steps to perform when testing an operation.
+
+  Attributes:
+    kind: A Kind value describing the kind of step to perform in the test.
+    transmission: Only valid for kinds Kind.INVOCATION_TRANSMISSION and
+      Kind.SERVICE_TRANSMISSION, a Transmission value describing the details of
+      the transmission to be made.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+    INVOCATION_TRANSMISSION = 'invocation transmission'
+    SERVICE_TRANSMISSION = 'service transmission'
+    INTERTRANSMISSION = 'intertransmission'
+    INVOCATION_CANCEL = 'invocation cancel'
+    SERVICE_CANCEL = 'service cancel'
+    INVOCATION_FAILURE = 'invocation failure'
+    SERVICE_FAILURE = 'service failure'
+
+
+class Outcome(collections.namedtuple('Outcome', ('invocation', 'service',))):
+  """A description of the expected outcome of an operation test.
+
+  Attributes:
+    invocation: The base.Outcome value expected on the invocation side of the
+      operation.
+    service: The base.Outcome value expected on the service side of the
+      operation.
+  """
+
+
+class Sequence(
+    collections.namedtuple(
+        'Sequence',
+        ('name', 'maximum_duration', 'invocation', 'elements', 'outcome',))):
+  """Describes at a high level steps to perform in a test.
+
+  Attributes:
+    name: The string name of the sequence.
+    maximum_duration: A length of time in seconds to allow for the test before
+      declaring it to have failed.
+    invocation: An Invocation value describing how to invoke the operation
+      under test.
+    elements: A sequence of Element values describing at coarse granularity
+      actions to take during the operation under test.
+    outcome: An Outcome value describing the expected outcome of the test.
+  """
+
+_EASY = Sequence(
+    'Easy',
+    test_constants.TIME_ALLOWANCE,
+    Invocation(test_constants.LONG_TIMEOUT, True, True, True),
+    (
+        Element(
+            Element.Kind.SERVICE_TRANSMISSION, Transmission(True, True, True)),
+    ),
+    Outcome(base.Outcome.COMPLETED, base.Outcome.COMPLETED))
+
+_PEASY = Sequence(
+    'Peasy',
+    test_constants.TIME_ALLOWANCE,
+    Invocation(test_constants.LONG_TIMEOUT, True, True, False),
+    (
+        Element(
+            Element.Kind.SERVICE_TRANSMISSION, Transmission(True, True, False)),
+        Element(
+            Element.Kind.INVOCATION_TRANSMISSION,
+            Transmission(False, True, True)),
+        Element(
+            Element.Kind.SERVICE_TRANSMISSION, Transmission(False, True, True)),
+    ),
+    Outcome(base.Outcome.COMPLETED, base.Outcome.COMPLETED))
+
+
+# TODO(issue 2959): Finish this test suite. This tuple of sequences should
+# contain at least the values in the Cartesian product of (half-duplex,
+# full-duplex) * (zero payloads, one payload, test_constants.STREAM_LENGTH
+# payloads) * (completion, cancellation, expiration, programming defect in
+# servicer code).
+SEQUENCES = (
+    _EASY,
+    _PEASY,
+)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/base/_state.py b/src/python/grpcio_test/grpc_test/framework/interfaces/base/_state.py
new file mode 100644
index 0000000000..21cf33aeb6
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/base/_state.py
@@ -0,0 +1,55 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Part of the tests of the base interface of RPC Framework."""
+
+
+class OperationState(object):
+
+  def __init__(self):
+    self.invocation_initial_metadata_in_flight = None
+    self.invocation_initial_metadata_received = False
+    self.invocation_payloads_in_flight = []
+    self.invocation_payloads_received = 0
+    self.invocation_completion_in_flight = None
+    self.invocation_completion_received = False
+    self.service_initial_metadata_in_flight = None
+    self.service_initial_metadata_received = False
+    self.service_payloads_in_flight = []
+    self.service_payloads_received = 0
+    self.service_completion_in_flight = None
+    self.service_completion_received = False
+    self.invocation_side_invocation_allowance = 1
+    self.invocation_side_service_allowance = 1
+    self.service_side_invocation_allowance = 1
+    self.service_side_service_allowance = 1
+    self.invocation_allowance_in_flight = 0
+    self.service_allowance_in_flight = 0
+    self.invocation_side_outcome = None
+    self.service_side_outcome = None
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/base/test_cases.py b/src/python/grpcio_test/grpc_test/framework/interfaces/base/test_cases.py
new file mode 100644
index 0000000000..5c8b176da4
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/base/test_cases.py
@@ -0,0 +1,262 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests of the base interface of RPC Framework."""
+
+import logging
+import random
+import threading
+import time
+import unittest
+
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.base import utilities
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.interfaces.base import _control
+from grpc_test.framework.interfaces.base import test_interfaces
+
+_SYNCHRONICITY_VARIATION = (('Sync', False), ('Async', True))
+
+_EMPTY_OUTCOME_DICT = {outcome: 0 for outcome in base.Outcome}
+
+
+class _Serialization(test_interfaces.Serialization):
+
+  def serialize_request(self, request):
+    return request + request
+
+  def deserialize_request(self, serialized_request):
+    return serialized_request[:len(serialized_request) / 2]
+
+  def serialize_response(self, response):
+    return response * 3
+
+  def deserialize_response(self, serialized_response):
+    return serialized_response[2 * len(serialized_response) / 3:]
+
+
+def _advance(quadruples, operator, controller):
+  try:
+    for quadruple in quadruples:
+      operator.advance(
+          initial_metadata=quadruple[0], payload=quadruple[1],
+          completion=quadruple[2], allowance=quadruple[3])
+  except Exception as e:  # pylint: disable=broad-except
+    controller.failed('Exception on advance: %e' % e)
+
+
+class _Operator(base.Operator):
+
+  def __init__(self, controller, on_advance, pool, operator_under_test):
+    self._condition = threading.Condition()
+    self._controller = controller
+    self._on_advance = on_advance
+    self._pool = pool
+    self._operator_under_test = operator_under_test
+    self._pending_advances = []
+
+  def set_operator_under_test(self, operator_under_test):
+    with self._condition:
+      self._operator_under_test = operator_under_test
+      pent_advances = self._pending_advances
+      self._pending_advances = []
+      pool = self._pool
+      controller = self._controller
+
+    if pool is None:
+      _advance(pent_advances, operator_under_test, controller)
+    else:
+      pool.submit(_advance, pent_advances, operator_under_test, controller)
+
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    on_advance = self._on_advance(
+        initial_metadata, payload, completion, allowance)
+    if on_advance.kind is _control.OnAdvance.Kind.ADVANCE:
+      with self._condition:
+        pool = self._pool
+        operator_under_test = self._operator_under_test
+        controller = self._controller
+
+      quadruple = (
+          on_advance.initial_metadata, on_advance.payload,
+          on_advance.completion, on_advance.allowance)
+      if pool is None:
+        _advance((quadruple,), operator_under_test, controller)
+      else:
+        pool.submit(_advance, (quadruple,), operator_under_test, controller)
+    elif on_advance.kind is _control.OnAdvance.Kind.DEFECT:
+      raise ValueError(
+          'Deliberately raised exception from Operator.advance (in a test)!')
+
+
+class _Servicer(base.Servicer):
+  """An base.Servicer with instrumented for testing."""
+
+  def __init__(self, group, method, controllers, pool):
+    self._condition = threading.Condition()
+    self._group = group
+    self._method = method
+    self._pool = pool
+    self._controllers = list(controllers)
+
+  def service(self, group, method, context, output_operator):
+    with self._condition:
+      controller = self._controllers.pop(0)
+      if group != self._group or method != self._method:
+        controller.fail(
+            '%s != %s or %s != %s' % (group, self._group, method, self._method))
+        raise base.NoSuchMethodError()
+      else:
+        operator = _Operator(
+            controller, controller.on_service_advance, self._pool,
+            output_operator)
+        outcome = context.add_termination_callback(
+            controller.service_on_termination)
+        if outcome is not None:
+          controller.service_on_termination(outcome)
+        return utilities.full_subscription(operator)
+
+
+class _OperationTest(unittest.TestCase):
+
+  def setUp(self):
+    if self._synchronicity_variation:
+      self._pool = logging_pool.pool(test_constants.POOL_SIZE)
+    else:
+      self._pool = None
+    self._controller = self._controller_creator.controller(
+        self._implementation, self._randomness)
+
+  def tearDown(self):
+    if self._synchronicity_variation:
+      self._pool.shutdown(wait=True)
+    else:
+      self._pool = None
+
+  def test_operation(self):
+    invocation = self._controller.invocation()
+    if invocation.subscription_kind is base.Subscription.Kind.FULL:
+      test_operator = _Operator(
+          self._controller, self._controller.on_invocation_advance,
+          self._pool, None)
+      subscription = utilities.full_subscription(test_operator)
+    else:
+      # TODO(nathaniel): support and test other subscription kinds.
+      self.fail('Non-full subscriptions not yet supported!')
+
+    servicer = _Servicer(
+        invocation.group, invocation.method, (self._controller,), self._pool)
+
+    invocation_end, service_end, memo = self._implementation.instantiate(
+        {(invocation.group, invocation.method): _Serialization()}, servicer)
+
+    try:
+      invocation_end.start()
+      service_end.start()
+      operation_context, operator_under_test = invocation_end.operate(
+          invocation.group, invocation.method, subscription, invocation.timeout,
+          initial_metadata=invocation.initial_metadata, payload=invocation.payload,
+          completion=invocation.completion)
+      test_operator.set_operator_under_test(operator_under_test)
+      outcome = operation_context.add_termination_callback(
+          self._controller.invocation_on_termination)
+      if outcome is not None:
+        self._controller.invocation_on_termination(outcome)
+    except Exception as e:  # pylint: disable=broad-except
+      self._controller.failed('Exception on invocation: %s' % e)
+      self.fail(e)
+
+    while True:
+      instruction = self._controller.poll()
+      if instruction.kind is _control.Instruction.Kind.ADVANCE:
+        try:
+          test_operator.advance(
+              *instruction.advance_args, **instruction.advance_kwargs)
+        except Exception as e:  # pylint: disable=broad-except
+          self._controller.failed('Exception on instructed advance: %s' % e)
+      elif instruction.kind is _control.Instruction.Kind.CANCEL:
+        try:
+          operation_context.cancel()
+        except Exception as e:  # pylint: disable=broad-except
+          self._controller.failed('Exception on cancel: %s' % e)
+      elif instruction.kind is _control.Instruction.Kind.CONCLUDE:
+        break
+
+    invocation_stop_event = invocation_end.stop(0)
+    service_stop_event = service_end.stop(0)
+    invocation_stop_event.wait()
+    service_stop_event.wait()
+    invocation_stats = invocation_end.operation_stats()
+    service_stats = service_end.operation_stats()
+
+    self._implementation.destantiate(memo)
+
+    self.assertTrue(
+        instruction.conclude_success, msg=instruction.conclude_message)
+
+    expected_invocation_stats = dict(_EMPTY_OUTCOME_DICT)
+    expected_invocation_stats[instruction.conclude_invocation_outcome] += 1
+    self.assertDictEqual(expected_invocation_stats, invocation_stats)
+    expected_service_stats = dict(_EMPTY_OUTCOME_DICT)
+    expected_service_stats[instruction.conclude_service_outcome] += 1
+    self.assertDictEqual(expected_service_stats, service_stats)
+
+
+def test_cases(implementation):
+  """Creates unittest.TestCase classes for a given Base implementation.
+
+  Args:
+    implementation: A test_interfaces.Implementation specifying creation and
+      destruction of the Base implementation under test.
+
+  Returns:
+    A sequence of subclasses of unittest.TestCase defining tests of the
+      specified Base layer implementation.
+  """
+  random_seed = hash(time.time())
+  logging.warning('Random seed for this execution: %s', random_seed)
+  randomness = random.Random(x=random_seed)
+
+  test_case_classes = []
+  for synchronicity_variation in _SYNCHRONICITY_VARIATION:
+    for controller_creator in _control.CONTROLLER_CREATORS:
+      name = ''.join(
+          (synchronicity_variation[0], controller_creator.name(), 'Test',))
+      test_case_classes.append(
+          type(name, (_OperationTest,),
+               {'_implementation': implementation,
+                '_randomness': randomness,
+                '_synchronicity_variation': synchronicity_variation[1],
+                '_controller_creator': controller_creator,
+               }))
+
+  return test_case_classes
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/base/test_interfaces.py b/src/python/grpcio_test/grpc_test/framework/interfaces/base/test_interfaces.py
new file mode 100644
index 0000000000..02426ab846
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/base/test_interfaces.py
@@ -0,0 +1,186 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Interfaces used in tests of implementations of the Base layer."""
+
+import abc
+
+from grpc.framework.interfaces.base import base  # pylint: disable=unused-import
+
+
+class Serialization(object):
+  """Specifies serialization and deserialization of test payloads."""
+  __metaclass__ = abc.ABCMeta
+
+  def serialize_request(self, request):
+    """Serializes a request value used in a test.
+
+    Args:
+      request: A request value created by a test.
+
+    Returns:
+      A bytestring that is the serialization of the given request.
+    """
+    raise NotImplementedError()
+
+  def deserialize_request(self, serialized_request):
+    """Deserializes a request value used in a test.
+
+    Args:
+      serialized_request: A bytestring that is the serialization of some request
+        used in a test.
+
+    Returns:
+      The request value encoded by the given bytestring.
+    """
+    raise NotImplementedError()
+
+  def serialize_response(self, response):
+    """Serializes a response value used in a test.
+
+    Args:
+      response: A response value created by a test.
+
+    Returns:
+      A bytestring that is the serialization of the given response.
+    """
+    raise NotImplementedError()
+
+  def deserialize_response(self, serialized_response):
+    """Deserializes a response value used in a test.
+
+    Args:
+      serialized_response: A bytestring that is the serialization of some
+        response used in a test.
+
+    Returns:
+      The response value encoded by the given bytestring.
+    """
+    raise NotImplementedError()
+
+
+class Implementation(object):
+  """Specifies an implementation of the Base layer."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def instantiate(self, serializations, servicer):
+    """Instantiates the Base layer implementation to be used in a test.
+
+    Args:
+      serializations: A dict from group-method pair to Serialization object
+        specifying how to serialize and deserialize payload values used in the
+        test.
+      servicer: A base.Servicer object to be called to service RPCs made during
+        the test.
+
+    Returns:
+      A sequence of length three the first element of which is a
+        base.End to be used to invoke RPCs, the second element of which is a
+        base.End to be used to service invoked RPCs, and the third element of
+        which is an arbitrary memo object to be kept and passed to destantiate
+        at the conclusion of the test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def destantiate(self, memo):
+    """Destroys the Base layer implementation under test.
+
+    Args:
+      memo: The object from the third position of the return value of a call to
+        instantiate.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_initial_metadata(self):
+    """Provides an operation's invocation-side initial metadata.
+
+    Returns:
+      A value to use for an operation's invocation-side initial metadata, or
+        None.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def service_initial_metadata(self):
+    """Provices an operation's service-side initial metadata.
+
+    Returns:
+      A value to use for an operation's service-side initial metadata, or
+        None.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_completion(self):
+    """Provides an operation's invocation-side completion.
+
+    Returns:
+      A base.Completion to use for an operation's invocation-side completion.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def service_completion(self):
+    """Provides an operation's service-side completion.
+
+    Returns:
+      A base.Completion to use for an operation's service-side completion.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    """Identifies whether or not metadata was properly transmitted.
+
+    Args:
+      original_metadata: A metadata value passed to the system under test.
+      transmitted_metadata: The same metadata value after having been
+        transmitted through the system under test.
+
+    Returns:
+      Whether or not the metadata was properly transmitted.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def completion_transmitted(self, original_completion, transmitted_completion):
+    """Identifies whether or not a base.Completion was properly transmitted.
+
+    Args:
+      original_completion: A base.Completion passed to the system under test.
+      transmitted_completion: The same completion value after having been
+        transmitted through the system under test.
+
+    Returns:
+      Whether or not the completion was properly transmitted.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/__init__.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_blocking_invocation_inline_service.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_blocking_invocation_inline_service.py
new file mode 100644
index 0000000000..857ad5cf3e
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_blocking_invocation_inline_service.py
@@ -0,0 +1,250 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test code for the Face layer of RPC Framework."""
+
+import abc
+import unittest
+
+# test_interfaces is referenced from specification in this module.
+from grpc.framework.interfaces.face import face
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.common import test_control
+from grpc_test.framework.common import test_coverage
+from grpc_test.framework.interfaces.face import _digest
+from grpc_test.framework.interfaces.face import _stock_service
+from grpc_test.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+
+class TestCase(test_coverage.Coverage, unittest.TestCase):
+  """A test of the Face layer of RPC Framework.
+
+  Concrete subclasses must have an "implementation" attribute of type
+  test_interfaces.Implementation and an "invoker_constructor" attribute of type
+  _invocation.InvokerConstructor.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  NAME = 'BlockingInvocationInlineServiceTest'
+
+  def setUp(self):
+    """See unittest.TestCase.setUp for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._control = test_control.PauseFailControl()
+    self._digest = _digest.digest(
+        _stock_service.STOCK_TEST_SERVICE, self._control, None)
+
+    generic_stub, dynamic_stubs, self._memo = self.implementation.instantiate(
+        self._digest.methods, self._digest.inline_method_implementations, None)
+    self._invoker = self.invoker_constructor.construct_invoker(
+        generic_stub, dynamic_stubs, self._digest.methods)
+
+  def tearDown(self):
+    """See unittest.TestCase.tearDown for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self.implementation.destantiate(self._memo)
+
+  def testSuccessfulUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response = self._invoker.blocking(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+
+        test_messages.verify(request, response, self)
+
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response_iterator = self._invoker.blocking(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(request, responses, self)
+
+  def testSuccessfulStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        response = self._invoker.blocking(group, method)(
+            iter(requests), test_constants.LONG_TIMEOUT)
+
+        test_messages.verify(requests, response, self)
+
+  def testSuccessfulStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        response_iterator = self._invoker.blocking(group, method)(
+            iter(requests), test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(requests, responses, self)
+
+  def testSequentialInvocations(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+
+        first_response = self._invoker.blocking(group, method)(
+            first_request, test_constants.LONG_TIMEOUT)
+
+        test_messages.verify(first_request, first_response, self)
+
+        second_response = self._invoker.blocking(group, method)(
+            second_request, test_constants.LONG_TIMEOUT)
+
+        test_messages.verify(second_request, second_response, self)
+
+  @unittest.skip('Parallel invocations impossible with blocking control flow!')
+  def testParallelInvocations(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Parallel invocations impossible with blocking control flow!')
+  def testWaitingForSomeButNotAllParallelInvocations(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledUnaryRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledUnaryRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledStreamRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledStreamRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  def testExpiredUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          self._invoker.blocking(group, method)(
+              request, test_constants.SHORT_TIMEOUT)
+
+  def testExpiredUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          response_iterator = self._invoker.blocking(group, method)(
+              request, test_constants.SHORT_TIMEOUT)
+          list(response_iterator)
+
+  def testExpiredStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          self._invoker.blocking(group, method)(
+              iter(requests), test_constants.SHORT_TIMEOUT)
+
+  def testExpiredStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          response_iterator = self._invoker.blocking(group, method)(
+              iter(requests), test_constants.SHORT_TIMEOUT)
+          list(response_iterator)
+
+  def testFailedUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          self._invoker.blocking(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+
+  def testFailedUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          response_iterator = self._invoker.blocking(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          list(response_iterator)
+
+  def testFailedStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          self._invoker.blocking(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+
+  def testFailedStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          response_iterator = self._invoker.blocking(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+          list(response_iterator)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_digest.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_digest.py
new file mode 100644
index 0000000000..da56ed7b27
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_digest.py
@@ -0,0 +1,444 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Code for making a service.TestService more amenable to use in tests."""
+
+import collections
+import threading
+
+# test_control, _service, and test_interfaces are referenced from specification
+# in this module.
+from grpc.framework.common import cardinality
+from grpc.framework.common import style
+from grpc.framework.foundation import stream
+from grpc.framework.foundation import stream_util
+from grpc.framework.interfaces.face import face
+from grpc_test.framework.common import test_control  # pylint: disable=unused-import
+from grpc_test.framework.interfaces.face import _service  # pylint: disable=unused-import
+from grpc_test.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+_IDENTITY = lambda x: x
+
+
+class TestServiceDigest(
+    collections.namedtuple(
+        'TestServiceDigest',
+        ('methods',
+         'inline_method_implementations',
+         'event_method_implementations',
+         'multi_method_implementation',
+         'unary_unary_messages_sequences',
+         'unary_stream_messages_sequences',
+         'stream_unary_messages_sequences',
+         'stream_stream_messages_sequences',))):
+  """A transformation of a service.TestService.
+
+  Attributes:
+    methods: A dict from method group-name pair to test_interfaces.Method object
+      describing the RPC methods that may be called during the test.
+    inline_method_implementations: A dict from method group-name pair to
+      face.MethodImplementation object to be used in tests of in-line calls to
+      behaviors under test.
+    event_method_implementations: A dict from method group-name pair to
+      face.MethodImplementation object to be used in tests of event-driven calls
+      to behaviors under test.
+    multi_method_implementation: A face.MultiMethodImplementation to be used in
+      tests of generic calls to behaviors under test.
+    unary_unary_messages_sequences: A dict from method group-name pair to
+      sequence of service.UnaryUnaryTestMessages objects to be used to test the
+      identified method.
+    unary_stream_messages_sequences: A dict from method group-name pair to
+      sequence of service.UnaryStreamTestMessages objects to be used to test the
+      identified method.
+    stream_unary_messages_sequences: A dict from method group-name pair to
+      sequence of service.StreamUnaryTestMessages objects to be used to test the
+      identified method.
+    stream_stream_messages_sequences: A dict from method group-name pair to
+      sequence of service.StreamStreamTestMessages objects to be used to test
+      the identified method.
+  """
+
+
+class _BufferingConsumer(stream.Consumer):
+  """A trivial Consumer that dumps what it consumes in a user-mutable buffer."""
+
+  def __init__(self):
+    self.consumed = []
+    self.terminated = False
+
+  def consume(self, value):
+    self.consumed.append(value)
+
+  def terminate(self):
+    self.terminated = True
+
+  def consume_and_terminate(self, value):
+    self.consumed.append(value)
+    self.terminated = True
+
+
+class _InlineUnaryUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, unary_unary_test_method, control):
+    self._test_method = unary_unary_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.UNARY_UNARY
+    self.style = style.Service.INLINE
+
+  def unary_unary_inline(self, request, context):
+    response_list = []
+    self._test_method.service(
+        request, response_list.append, context, self._control)
+    return response_list.pop(0)
+
+
+class _EventUnaryUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, unary_unary_test_method, control, pool):
+    self._test_method = unary_unary_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.UNARY_UNARY
+    self.style = style.Service.EVENT
+
+  def unary_unary_event(self, request, response_callback, context):
+    if self._pool is None:
+      self._test_method.service(
+          request, response_callback, context, self._control)
+    else:
+      self._pool.submit(
+          self._test_method.service, request, response_callback, context,
+          self._control)
+
+
+class _InlineUnaryStreamMethod(face.MethodImplementation):
+
+  def __init__(self, unary_stream_test_method, control):
+    self._test_method = unary_stream_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.UNARY_STREAM
+    self.style = style.Service.INLINE
+
+  def unary_stream_inline(self, request, context):
+    response_consumer = _BufferingConsumer()
+    self._test_method.service(
+        request, response_consumer, context, self._control)
+    for response in response_consumer.consumed:
+      yield response
+
+
+class _EventUnaryStreamMethod(face.MethodImplementation):
+
+  def __init__(self, unary_stream_test_method, control, pool):
+    self._test_method = unary_stream_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.UNARY_STREAM
+    self.style = style.Service.EVENT
+
+  def unary_stream_event(self, request, response_consumer, context):
+    if self._pool is None:
+      self._test_method.service(
+          request, response_consumer, context, self._control)
+    else:
+      self._pool.submit(
+          self._test_method.service, request, response_consumer, context,
+          self._control)
+
+
+class _InlineStreamUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, stream_unary_test_method, control):
+    self._test_method = stream_unary_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.STREAM_UNARY
+    self.style = style.Service.INLINE
+
+  def stream_unary_inline(self, request_iterator, context):
+    response_list = []
+    request_consumer = self._test_method.service(
+        response_list.append, context, self._control)
+    for request in request_iterator:
+      request_consumer.consume(request)
+    request_consumer.terminate()
+    return response_list.pop(0)
+
+
+class _EventStreamUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, stream_unary_test_method, control, pool):
+    self._test_method = stream_unary_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.STREAM_UNARY
+    self.style = style.Service.EVENT
+
+  def stream_unary_event(self, response_callback, context):
+    request_consumer = self._test_method.service(
+        response_callback, context, self._control)
+    if self._pool is None:
+      return request_consumer
+    else:
+      return stream_util.ThreadSwitchingConsumer(request_consumer, self._pool)
+
+
+class _InlineStreamStreamMethod(face.MethodImplementation):
+
+  def __init__(self, stream_stream_test_method, control):
+    self._test_method = stream_stream_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.STREAM_STREAM
+    self.style = style.Service.INLINE
+
+  def stream_stream_inline(self, request_iterator, context):
+    response_consumer = _BufferingConsumer()
+    request_consumer = self._test_method.service(
+        response_consumer, context, self._control)
+
+    for request in request_iterator:
+      request_consumer.consume(request)
+      while response_consumer.consumed:
+        yield response_consumer.consumed.pop(0)
+    response_consumer.terminate()
+
+
+class _EventStreamStreamMethod(face.MethodImplementation):
+
+  def __init__(self, stream_stream_test_method, control, pool):
+    self._test_method = stream_stream_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.STREAM_STREAM
+    self.style = style.Service.EVENT
+
+  def stream_stream_event(self, response_consumer, context):
+    request_consumer = self._test_method.service(
+        response_consumer, context, self._control)
+    if self._pool is None:
+      return request_consumer
+    else:
+      return stream_util.ThreadSwitchingConsumer(request_consumer, self._pool)
+
+
+class _UnaryConsumer(stream.Consumer):
+  """A Consumer that only allows consumption of exactly one value."""
+
+  def __init__(self, action):
+    self._lock = threading.Lock()
+    self._action = action
+    self._consumed = False
+    self._terminated = False
+
+  def consume(self, value):
+    with self._lock:
+      if self._consumed:
+        raise ValueError('Unary consumer already consumed!')
+      elif self._terminated:
+        raise ValueError('Unary consumer already terminated!')
+      else:
+        self._consumed = True
+
+    self._action(value)
+
+  def terminate(self):
+    with self._lock:
+      if not self._consumed:
+        raise ValueError('Unary consumer hasn\'t yet consumed!')
+      elif self._terminated:
+        raise ValueError('Unary consumer already terminated!')
+      else:
+        self._terminated = True
+
+  def consume_and_terminate(self, value):
+    with self._lock:
+      if self._consumed:
+        raise ValueError('Unary consumer already consumed!')
+      elif self._terminated:
+        raise ValueError('Unary consumer already terminated!')
+      else:
+        self._consumed = True
+        self._terminated = True
+
+    self._action(value)
+
+
+class _UnaryUnaryAdaptation(object):
+
+  def __init__(self, unary_unary_test_method):
+    self._method = unary_unary_test_method
+
+  def service(self, response_consumer, context, control):
+    def action(request):
+      self._method.service(
+          request, response_consumer.consume_and_terminate, context, control)
+    return _UnaryConsumer(action)
+
+
+class _UnaryStreamAdaptation(object):
+
+  def __init__(self, unary_stream_test_method):
+    self._method = unary_stream_test_method
+
+  def service(self, response_consumer, context, control):
+    def action(request):
+      self._method.service(request, response_consumer, context, control)
+    return _UnaryConsumer(action)
+
+
+class _StreamUnaryAdaptation(object):
+
+  def __init__(self, stream_unary_test_method):
+    self._method = stream_unary_test_method
+
+  def service(self, response_consumer, context, control):
+    return self._method.service(
+        response_consumer.consume_and_terminate, context, control)
+
+
+class _MultiMethodImplementation(face.MultiMethodImplementation):
+
+  def __init__(self, methods, control, pool):
+    self._methods = methods
+    self._control = control
+    self._pool = pool
+
+  def service(self, group, name, response_consumer, context):
+    method = self._methods.get(group, name, None)
+    if method is None:
+      raise face.NoSuchMethodError(group, name)
+    elif self._pool is None:
+      return method(response_consumer, context, self._control)
+    else:
+      request_consumer = method(response_consumer, context, self._control)
+      return stream_util.ThreadSwitchingConsumer(request_consumer, self._pool)
+
+
+class _Assembly(
+    collections.namedtuple(
+        '_Assembly',
+        ['methods', 'inlines', 'events', 'adaptations', 'messages'])):
+  """An intermediate structure created when creating a TestServiceDigest."""
+
+
+def _assemble(
+    scenarios, identifiers, inline_method_constructor, event_method_constructor,
+    adapter, control, pool):
+  """Creates an _Assembly from the given scenarios."""
+  methods = {}
+  inlines = {}
+  events = {}
+  adaptations = {}
+  messages = {}
+  for identifier, scenario in scenarios.iteritems():
+    if identifier in identifiers:
+      raise ValueError('Repeated identifier "(%s, %s)"!' % identifier)
+
+    test_method = scenario[0]
+    inline_method = inline_method_constructor(test_method, control)
+    event_method = event_method_constructor(test_method, control, pool)
+    adaptation = adapter(test_method)
+
+    methods[identifier] = test_method
+    inlines[identifier] = inline_method
+    events[identifier] = event_method
+    adaptations[identifier] = adaptation
+    messages[identifier] = scenario[1]
+
+  return _Assembly(methods, inlines, events, adaptations, messages)
+
+
+def digest(service, control, pool):
+  """Creates a TestServiceDigest from a TestService.
+
+  Args:
+    service: A _service.TestService.
+    control: A test_control.Control.
+    pool: If RPC methods should be serviced in a separate thread, a thread pool.
+      None if RPC methods should be serviced in the thread belonging to the
+      run-time that calls for their service.
+
+  Returns:
+    A TestServiceDigest synthesized from the given service.TestService.
+  """
+  identifiers = set()
+
+  unary_unary = _assemble(
+      service.unary_unary_scenarios(), identifiers, _InlineUnaryUnaryMethod,
+      _EventUnaryUnaryMethod, _UnaryUnaryAdaptation, control, pool)
+  identifiers.update(unary_unary.inlines)
+
+  unary_stream = _assemble(
+      service.unary_stream_scenarios(), identifiers, _InlineUnaryStreamMethod,
+      _EventUnaryStreamMethod, _UnaryStreamAdaptation, control, pool)
+  identifiers.update(unary_stream.inlines)
+
+  stream_unary = _assemble(
+      service.stream_unary_scenarios(), identifiers, _InlineStreamUnaryMethod,
+      _EventStreamUnaryMethod, _StreamUnaryAdaptation, control, pool)
+  identifiers.update(stream_unary.inlines)
+
+  stream_stream = _assemble(
+      service.stream_stream_scenarios(), identifiers, _InlineStreamStreamMethod,
+      _EventStreamStreamMethod, _IDENTITY, control, pool)
+  identifiers.update(stream_stream.inlines)
+
+  methods = dict(unary_unary.methods)
+  methods.update(unary_stream.methods)
+  methods.update(stream_unary.methods)
+  methods.update(stream_stream.methods)
+  adaptations = dict(unary_unary.adaptations)
+  adaptations.update(unary_stream.adaptations)
+  adaptations.update(stream_unary.adaptations)
+  adaptations.update(stream_stream.adaptations)
+  inlines = dict(unary_unary.inlines)
+  inlines.update(unary_stream.inlines)
+  inlines.update(stream_unary.inlines)
+  inlines.update(stream_stream.inlines)
+  events = dict(unary_unary.events)
+  events.update(unary_stream.events)
+  events.update(stream_unary.events)
+  events.update(stream_stream.events)
+
+  return TestServiceDigest(
+      methods,
+      inlines,
+      events,
+      _MultiMethodImplementation(adaptations, control, pool),
+      unary_unary.messages,
+      unary_stream.messages,
+      stream_unary.messages,
+      stream_stream.messages)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_event_invocation_synchronous_event_service.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_event_invocation_synchronous_event_service.py
new file mode 100644
index 0000000000..ea5cdeaea3
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_event_invocation_synchronous_event_service.py
@@ -0,0 +1,377 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test code for the Face layer of RPC Framework."""
+
+import abc
+import unittest
+
+# test_interfaces is referenced from specification in this module.
+from grpc.framework.interfaces.face import face
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.common import test_control
+from grpc_test.framework.common import test_coverage
+from grpc_test.framework.interfaces.face import _digest
+from grpc_test.framework.interfaces.face import _receiver
+from grpc_test.framework.interfaces.face import _stock_service
+from grpc_test.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+
+class TestCase(test_coverage.Coverage, unittest.TestCase):
+  """A test of the Face layer of RPC Framework.
+
+  Concrete subclasses must have an "implementation" attribute of type
+  test_interfaces.Implementation and an "invoker_constructor" attribute of type
+  _invocation.InvokerConstructor.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  NAME = 'EventInvocationSynchronousEventServiceTest'
+
+  def setUp(self):
+    """See unittest.TestCase.setUp for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._control = test_control.PauseFailControl()
+    self._digest = _digest.digest(
+        _stock_service.STOCK_TEST_SERVICE, self._control, None)
+
+    generic_stub, dynamic_stubs, self._memo = self.implementation.instantiate(
+        self._digest.methods, self._digest.event_method_implementations, None)
+    self._invoker = self.invoker_constructor.construct_invoker(
+        generic_stub, dynamic_stubs, self._digest.methods)
+
+  def tearDown(self):
+    """See unittest.TestCase.tearDown for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self.implementation.destantiate(self._memo)
+
+  def testSuccessfulUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        self._invoker.event(group, method)(
+            request, receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        receiver.block_until_terminated()
+        response = receiver.unary_response()
+
+        test_messages.verify(request, response, self)
+
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        self._invoker.event(group, method)(
+            request, receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        receiver.block_until_terminated()
+        responses = receiver.stream_responses()
+
+        test_messages.verify(request, responses, self)
+
+  def testSuccessfulStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        receiver = _receiver.Receiver()
+
+        call_consumer = self._invoker.event(group, method)(
+            receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        for request in requests:
+          call_consumer.consume(request)
+        call_consumer.terminate()
+        receiver.block_until_terminated()
+        response = receiver.unary_response()
+
+        test_messages.verify(requests, response, self)
+
+  def testSuccessfulStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        receiver = _receiver.Receiver()
+
+        call_consumer = self._invoker.event(group, method)(
+            receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        for request in requests:
+          call_consumer.consume(request)
+        call_consumer.terminate()
+        receiver.block_until_terminated()
+        responses = receiver.stream_responses()
+
+        test_messages.verify(requests, responses, self)
+
+  def testSequentialInvocations(self):
+    # pylint: disable=cell-var-from-loop
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+        second_receiver = _receiver.Receiver()
+
+        def make_second_invocation():
+          self._invoker.event(group, method)(
+              second_request, second_receiver, second_receiver.abort,
+              test_constants.LONG_TIMEOUT)
+
+        class FirstReceiver(_receiver.Receiver):
+
+          def complete(self, terminal_metadata, code, details):
+            super(FirstReceiver, self).complete(
+                terminal_metadata, code, details)
+            make_second_invocation()
+
+        first_receiver = FirstReceiver()
+
+        self._invoker.event(group, method)(
+            first_request, first_receiver, first_receiver.abort,
+            test_constants.LONG_TIMEOUT)
+        second_receiver.block_until_terminated()
+
+        first_response = first_receiver.unary_response()
+        second_response = second_receiver.unary_response()
+        test_messages.verify(first_request, first_response, self)
+        test_messages.verify(second_request, second_response, self)
+
+  def testParallelInvocations(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        first_receiver = _receiver.Receiver()
+        second_request = test_messages.request()
+        second_receiver = _receiver.Receiver()
+
+        self._invoker.event(group, method)(
+            first_request, first_receiver, first_receiver.abort,
+            test_constants.LONG_TIMEOUT)
+        self._invoker.event(group, method)(
+            second_request, second_receiver, second_receiver.abort,
+            test_constants.LONG_TIMEOUT)
+        first_receiver.block_until_terminated()
+        second_receiver.block_until_terminated()
+
+        first_response = first_receiver.unary_response()
+        second_response = second_receiver.unary_response()
+        test_messages.verify(first_request, first_response, self)
+        test_messages.verify(second_request, second_response, self)
+
+  @unittest.skip('TODO(nathaniel): implement.')
+  def testWaitingForSomeButNotAllParallelInvocations(self):
+    raise NotImplementedError()
+
+  def testCancelledUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        with self._control.pause():
+          call = self._invoker.event(group, method)(
+              request, receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+          call.cancel()
+          receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.CANCELLED, receiver.abortion().kind)
+
+  def testCancelledUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        call = self._invoker.event(group, method)(
+            request, receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        call.cancel()
+        receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.CANCELLED, receiver.abortion().kind)
+
+  def testCancelledStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        receiver = _receiver.Receiver()
+
+        call_consumer = self._invoker.event(group, method)(
+            receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        for request in requests:
+          call_consumer.consume(request)
+        call_consumer.cancel()
+        receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.CANCELLED, receiver.abortion().kind)
+
+  def testCancelledStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for unused_test_messages in test_messages_sequence:
+        receiver = _receiver.Receiver()
+
+        call_consumer = self._invoker.event(group, method)(
+            receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+        call_consumer.cancel()
+        receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.CANCELLED, receiver.abortion().kind)
+
+  def testExpiredUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        with self._control.pause():
+          self._invoker.event(group, method)(
+              request, receiver, receiver.abort, test_constants.SHORT_TIMEOUT)
+          receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.EXPIRED, receiver.abortion().kind)
+
+  def testExpiredUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        with self._control.pause():
+          self._invoker.event(group, method)(
+              request, receiver, receiver.abort, test_constants.SHORT_TIMEOUT)
+          receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.EXPIRED, receiver.abortion().kind)
+
+  def testExpiredStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for unused_test_messages in test_messages_sequence:
+        receiver = _receiver.Receiver()
+
+        self._invoker.event(group, method)(
+            receiver, receiver.abort, test_constants.SHORT_TIMEOUT)
+        receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.EXPIRED, receiver.abortion().kind)
+
+  def testExpiredStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        receiver = _receiver.Receiver()
+
+        call_consumer = self._invoker.event(group, method)(
+            receiver, receiver.abort, test_constants.SHORT_TIMEOUT)
+        for request in requests:
+          call_consumer.consume(request)
+        receiver.block_until_terminated()
+
+        self.assertIs(face.Abortion.Kind.EXPIRED, receiver.abortion().kind)
+
+  def testFailedUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        with self._control.fail():
+          self._invoker.event(group, method)(
+              request, receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+          receiver.block_until_terminated()
+
+        self.assertIs(
+            face.Abortion.Kind.REMOTE_FAILURE, receiver.abortion().kind)
+
+  def testFailedUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        receiver = _receiver.Receiver()
+
+        with self._control.fail():
+          self._invoker.event(group, method)(
+              request, receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+          receiver.block_until_terminated()
+
+        self.assertIs(
+            face.Abortion.Kind.REMOTE_FAILURE, receiver.abortion().kind)
+
+  def testFailedStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        receiver = _receiver.Receiver()
+
+        with self._control.fail():
+          call_consumer = self._invoker.event(group, method)(
+              receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+          for request in requests:
+            call_consumer.consume(request)
+          call_consumer.terminate()
+          receiver.block_until_terminated()
+
+        self.assertIs(
+            face.Abortion.Kind.REMOTE_FAILURE, receiver.abortion().kind)
+
+  def testFailedStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        receiver = _receiver.Receiver()
+
+        with self._control.fail():
+          call_consumer = self._invoker.event(group, method)(
+              receiver, receiver.abort, test_constants.LONG_TIMEOUT)
+          for request in requests:
+            call_consumer.consume(request)
+          call_consumer.terminate()
+          receiver.block_until_terminated()
+
+        self.assertIs(
+            face.Abortion.Kind.REMOTE_FAILURE, receiver.abortion().kind)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_future_invocation_asynchronous_event_service.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_future_invocation_asynchronous_event_service.py
new file mode 100644
index 0000000000..a649362cef
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_future_invocation_asynchronous_event_service.py
@@ -0,0 +1,378 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test code for the Face layer of RPC Framework."""
+
+import abc
+import contextlib
+import threading
+import unittest
+
+# test_interfaces is referenced from specification in this module.
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.face import face
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.common import test_control
+from grpc_test.framework.common import test_coverage
+from grpc_test.framework.interfaces.face import _digest
+from grpc_test.framework.interfaces.face import _stock_service
+from grpc_test.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+
+class _PauseableIterator(object):
+
+  def __init__(self, upstream):
+    self._upstream = upstream
+    self._condition = threading.Condition()
+    self._paused = False
+
+  @contextlib.contextmanager
+  def pause(self):
+    with self._condition:
+      self._paused = True
+    yield
+    with self._condition:
+      self._paused = False
+      self._condition.notify_all()
+
+  def __iter__(self):
+    return self
+
+  def next(self):
+    with self._condition:
+      while self._paused:
+        self._condition.wait()
+    return next(self._upstream)
+
+
+class TestCase(test_coverage.Coverage, unittest.TestCase):
+  """A test of the Face layer of RPC Framework.
+
+  Concrete subclasses must have an "implementation" attribute of type
+  test_interfaces.Implementation and an "invoker_constructor" attribute of type
+  _invocation.InvokerConstructor.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  NAME = 'FutureInvocationAsynchronousEventServiceTest'
+
+  def setUp(self):
+    """See unittest.TestCase.setUp for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._control = test_control.PauseFailControl()
+    self._digest_pool = logging_pool.pool(test_constants.POOL_SIZE)
+    self._digest = _digest.digest(
+        _stock_service.STOCK_TEST_SERVICE, self._control, self._digest_pool)
+
+    generic_stub, dynamic_stubs, self._memo = self.implementation.instantiate(
+        self._digest.methods, self._digest.event_method_implementations, None)
+    self._invoker = self.invoker_constructor.construct_invoker(
+        generic_stub, dynamic_stubs, self._digest.methods)
+
+  def tearDown(self):
+    """See unittest.TestCase.tearDown for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self.implementation.destantiate(self._memo)
+    self._digest_pool.shutdown(wait=True)
+
+  def testSuccessfulUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response_future = self._invoker.future(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+        response = response_future.result()
+
+        test_messages.verify(request, response, self)
+
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response_iterator = self._invoker.future(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(request, responses, self)
+
+  def testSuccessfulStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        request_iterator = _PauseableIterator(iter(requests))
+
+        # Use of a paused iterator of requests allows us to test that control is
+        # returned to calling code before the iterator yields any requests.
+        with request_iterator.pause():
+          response_future = self._invoker.future(group, method)(
+              request_iterator, test_constants.LONG_TIMEOUT)
+        response = response_future.result()
+
+        test_messages.verify(requests, response, self)
+
+  def testSuccessfulStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        request_iterator = _PauseableIterator(iter(requests))
+
+        # Use of a paused iterator of requests allows us to test that control is
+        # returned to calling code before the iterator yields any requests.
+        with request_iterator.pause():
+          response_iterator = self._invoker.future(group, method)(
+              request_iterator, test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(requests, responses, self)
+
+  def testSequentialInvocations(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+
+        first_response_future = self._invoker.future(group, method)(
+            first_request, test_constants.LONG_TIMEOUT)
+        first_response = first_response_future.result()
+
+        test_messages.verify(first_request, first_response, self)
+
+        second_response_future = self._invoker.future(group, method)(
+            second_request, test_constants.LONG_TIMEOUT)
+        second_response = second_response_future.result()
+
+        test_messages.verify(second_request, second_response, self)
+
+  def testParallelInvocations(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+
+        first_response_future = self._invoker.future(group, method)(
+            first_request, test_constants.LONG_TIMEOUT)
+        second_response_future = self._invoker.future(group, method)(
+            second_request, test_constants.LONG_TIMEOUT)
+        first_response = first_response_future.result()
+        second_response = second_response_future.result()
+
+        test_messages.verify(first_request, first_response, self)
+        test_messages.verify(second_request, second_response, self)
+
+  @unittest.skip('TODO(nathaniel): implement.')
+  def testWaitingForSomeButNotAllParallelInvocations(self):
+    raise NotImplementedError()
+
+  def testCancelledUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause():
+          response_future = self._invoker.future(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          cancel_method_return_value = response_future.cancel()
+
+        self.assertFalse(cancel_method_return_value)
+        self.assertTrue(response_future.cancelled())
+
+  def testCancelledUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          response_iterator.cancel()
+
+        with self.assertRaises(face.CancellationError):
+          next(response_iterator)
+
+  def testCancelledStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause():
+          response_future = self._invoker.future(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+          cancel_method_return_value = response_future.cancel()
+
+        self.assertFalse(cancel_method_return_value)
+        self.assertTrue(response_future.cancelled())
+
+  def testCancelledStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+          response_iterator.cancel()
+
+        with self.assertRaises(face.CancellationError):
+          next(response_iterator)
+
+  def testExpiredUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause():
+          response_future = self._invoker.future(
+              group, method)(request, test_constants.SHORT_TIMEOUT)
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testExpiredUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              request, test_constants.SHORT_TIMEOUT)
+          with self.assertRaises(face.ExpirationError):
+            list(response_iterator)
+
+  def testExpiredStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause():
+          response_future = self._invoker.future(group, method)(
+              iter(requests), test_constants.SHORT_TIMEOUT)
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testExpiredStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              iter(requests), test_constants.SHORT_TIMEOUT)
+          with self.assertRaises(face.ExpirationError):
+            list(response_iterator)
+
+  def testFailedUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.fail():
+          response_future = self._invoker.future(group, method)(
+              request, test_constants.SHORT_TIMEOUT)
+
+          # Because the servicer fails outside of the thread from which the
+          # servicer-side runtime called into it its failure is
+          # indistinguishable from simply not having called its
+          # response_callback before the expiration of the RPC.
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testFailedUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        # Because the servicer fails outside of the thread from which the
+        # servicer-side runtime called into it its failure is indistinguishable
+        # from simply not having called its response_consumer before the
+        # expiration of the RPC.
+        with self._control.fail(), self.assertRaises(face.ExpirationError):
+          response_iterator = self._invoker.future(group, method)(
+              request, test_constants.SHORT_TIMEOUT)
+          list(response_iterator)
+
+  def testFailedStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.fail():
+          response_future = self._invoker.future(group, method)(
+              iter(requests), test_constants.SHORT_TIMEOUT)
+
+          # Because the servicer fails outside of the thread from which the
+          # servicer-side runtime called into it its failure is
+          # indistinguishable from simply not having called its
+          # response_callback before the expiration of the RPC.
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testFailedStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        self._digest.stream_stream_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        # Because the servicer fails outside of the thread from which the
+        # servicer-side runtime called into it its failure is indistinguishable
+        # from simply not having called its response_consumer before the
+        # expiration of the RPC.
+        with self._control.fail(), self.assertRaises(face.ExpirationError):
+          response_iterator = self._invoker.future(group, method)(
+              iter(requests), test_constants.SHORT_TIMEOUT)
+          list(response_iterator)
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_invocation.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_invocation.py
new file mode 100644
index 0000000000..448e845a08
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_invocation.py
@@ -0,0 +1,213 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Coverage across the Face layer's generic-to-dynamic range for invocation."""
+
+import abc
+
+from grpc.framework.common import cardinality
+
+_CARDINALITY_TO_GENERIC_BLOCKING_BEHAVIOR = {
+    cardinality.Cardinality.UNARY_UNARY: 'blocking_unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'inline_unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'blocking_stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'inline_stream_stream',
+}
+
+_CARDINALITY_TO_GENERIC_FUTURE_BEHAVIOR = {
+    cardinality.Cardinality.UNARY_UNARY: 'future_unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'inline_unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'future_stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'inline_stream_stream',
+}
+
+_CARDINALITY_TO_GENERIC_EVENT_BEHAVIOR = {
+    cardinality.Cardinality.UNARY_UNARY: 'event_unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'event_unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'event_stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'event_stream_stream',
+}
+
+_CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE = {
+    cardinality.Cardinality.UNARY_UNARY: 'unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'stream_stream',
+}
+
+
+class Invoker(object):
+  """A type used to invoke test RPCs."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def blocking(self, group, name):
+    """Invokes an RPC with blocking control flow."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def future(self, group, name):
+    """Invokes an RPC with future control flow."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event(self, group, name):
+    """Invokes an RPC with event control flow."""
+    raise NotImplementedError()
+
+
+class InvokerConstructor(object):
+  """A type used to create Invokers."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def name(self):
+    """Specifies the name of the Invoker constructed by this object."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def construct_invoker(self, generic_stub, dynamic_stubs, methods):
+    """Constructs an Invoker for the given stubs and methods."""
+    raise NotImplementedError()
+
+
+class _GenericInvoker(Invoker):
+
+  def __init__(self, generic_stub, methods):
+    self._stub = generic_stub
+    self._methods = methods
+
+  def _behavior(self, group, name, cardinality_to_generic_method):
+    method_cardinality = self._methods[group, name].cardinality()
+    behavior = getattr(
+        self._stub, cardinality_to_generic_method[method_cardinality])
+    return lambda *args, **kwargs: behavior(group, name, *args, **kwargs)
+
+  def blocking(self, group, name):
+    return self._behavior(
+        group, name, _CARDINALITY_TO_GENERIC_BLOCKING_BEHAVIOR)
+
+  def future(self, group, name):
+    return self._behavior(group, name, _CARDINALITY_TO_GENERIC_FUTURE_BEHAVIOR)
+
+  def event(self, group, name):
+    return self._behavior(group, name, _CARDINALITY_TO_GENERIC_EVENT_BEHAVIOR)
+
+
+class _GenericInvokerConstructor(InvokerConstructor):
+
+  def name(self):
+    return 'GenericInvoker'
+
+  def construct_invoker(self, generic_stub, dynamic_stub, methods):
+    return _GenericInvoker(generic_stub, methods)
+
+
+class _MultiCallableInvoker(Invoker):
+
+  def __init__(self, generic_stub, methods):
+    self._stub = generic_stub
+    self._methods = methods
+
+  def _multi_callable(self, group, name):
+    method_cardinality = self._methods[group, name].cardinality()
+    behavior = getattr(
+        self._stub,
+        _CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE[method_cardinality])
+    return behavior(group, name)
+
+  def blocking(self, group, name):
+    return self._multi_callable(group, name)
+
+  def future(self, group, name):
+    method_cardinality = self._methods[group, name].cardinality()
+    behavior = getattr(
+        self._stub,
+        _CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE[method_cardinality])
+    if method_cardinality in (
+        cardinality.Cardinality.UNARY_UNARY,
+        cardinality.Cardinality.STREAM_UNARY):
+      return behavior(group, name).future
+    else:
+      return behavior(group, name)
+
+  def event(self, group, name):
+    return self._multi_callable(group, name).event
+
+
+class _MultiCallableInvokerConstructor(InvokerConstructor):
+
+  def name(self):
+    return 'MultiCallableInvoker'
+
+  def construct_invoker(self, generic_stub, dynamic_stub, methods):
+    return _MultiCallableInvoker(generic_stub, methods)
+
+
+class _DynamicInvoker(Invoker):
+
+  def __init__(self, dynamic_stubs, methods):
+    self._stubs = dynamic_stubs
+    self._methods = methods
+
+  def blocking(self, group, name):
+    return getattr(self._stubs[group], name)
+
+  def future(self, group, name):
+    if self._methods[group, name].cardinality() in (
+        cardinality.Cardinality.UNARY_UNARY,
+        cardinality.Cardinality.STREAM_UNARY):
+      return getattr(self._stubs[group], name).future
+    else:
+      return getattr(self._stubs[group], name)
+
+  def event(self, group, name):
+    return getattr(self._stubs[group], name).event
+
+
+class _DynamicInvokerConstructor(InvokerConstructor):
+
+  def name(self):
+    return 'DynamicInvoker'
+
+  def construct_invoker(self, generic_stub, dynamic_stubs, methods):
+    return _DynamicInvoker(dynamic_stubs, methods)
+
+
+def invoker_constructors():
+  """Creates a sequence of InvokerConstructors to use in tests of RPCs.
+
+  Returns:
+    A sequence of InvokerConstructors.
+  """
+  return (
+      _GenericInvokerConstructor(),
+      _MultiCallableInvokerConstructor(),
+      _DynamicInvokerConstructor(),
+  )
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_receiver.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_receiver.py
new file mode 100644
index 0000000000..2e444ff09d
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_receiver.py
@@ -0,0 +1,95 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""A utility useful in tests of asynchronous, event-driven interfaces."""
+
+import threading
+
+from grpc.framework.interfaces.face import face
+
+
+class Receiver(face.ResponseReceiver):
+  """A utility object useful in tests of asynchronous code."""
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._initial_metadata = None
+    self._responses = []
+    self._terminal_metadata = None
+    self._code = None
+    self._details = None
+    self._completed = False
+    self._abortion = None
+
+  def abort(self, abortion):
+    with self._condition:
+      self._abortion = abortion
+      self._condition.notify_all()
+
+  def initial_metadata(self, initial_metadata):
+    with self._condition:
+      self._initial_metadata = initial_metadata
+
+  def response(self, response):
+    with self._condition:
+      self._responses.append(response)
+
+  def complete(self, terminal_metadata, code, details):
+    with self._condition:
+      self._terminal_metadata = terminal_metadata
+      self._code = code
+      self._details = details
+      self._completed = True
+      self._condition.notify_all()
+
+  def block_until_terminated(self):
+    with self._condition:
+      while self._abortion is None and not self._completed:
+        self._condition.wait()
+
+  def unary_response(self):
+    with self._condition:
+      if self._abortion is not None:
+        raise AssertionError('Aborted with abortion "%s"!' % self._abortion)
+      elif len(self._responses) != 1:
+        raise AssertionError(
+            '%d responses received, not exactly one!', len(self._responses))
+      else:
+        return self._responses[0]
+
+  def stream_responses(self):
+    with self._condition:
+      if self._abortion is None:
+        return list(self._responses)
+      else:
+        raise AssertionError('Aborted with abortion "%s"!' % self._abortion)
+
+  def abortion(self):
+    with self._condition:
+      return self._abortion
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_service.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_service.py
new file mode 100644
index 0000000000..e25b8a038c
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_service.py
@@ -0,0 +1,332 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Private interfaces implemented by data sets used in Face-layer tests."""
+
+import abc
+
+# face is referenced from specification in this module.
+from grpc.framework.interfaces.face import face  # pylint: disable=unused-import
+from grpc_test.framework.interfaces.face import test_interfaces
+
+
+class UnaryUnaryTestMethodImplementation(test_interfaces.Method):
+  """A controllable implementation of a unary-unary method."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def service(self, request, response_callback, context, control):
+    """Services an RPC that accepts one message and produces one message.
+
+    Args:
+      request: The single request message for the RPC.
+      response_callback: A callback to be called to accept the response message
+        of the RPC.
+      context: An face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class UnaryUnaryTestMessages(object):
+  """A type for unary-request-unary-response message pairings."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def request(self):
+    """Affords a request message.
+
+    Implementations of this method should return a different message with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A request message.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, request, response, test_case):
+    """Verifies that the computed response matches the given request.
+
+    Args:
+      request: A request message.
+      response: A response message.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the request and response do not match, indicating that
+        there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class UnaryStreamTestMethodImplementation(test_interfaces.Method):
+  """A controllable implementation of a unary-stream method."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def service(self, request, response_consumer, context, control):
+    """Services an RPC that takes one message and produces a stream of messages.
+
+    Args:
+      request: The single request message for the RPC.
+      response_consumer: A stream.Consumer to be called to accept the response
+        messages of the RPC.
+      context: A face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class UnaryStreamTestMessages(object):
+  """A type for unary-request-stream-response message pairings."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def request(self):
+    """Affords a request message.
+
+    Implementations of this method should return a different message with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A request message.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, request, responses, test_case):
+    """Verifies that the computed responses match the given request.
+
+    Args:
+      request: A request message.
+      responses: A sequence of response messages.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the request and responses do not match, indicating that
+        there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class StreamUnaryTestMethodImplementation(test_interfaces.Method):
+  """A controllable implementation of a stream-unary method."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def service(self, response_callback, context, control):
+    """Services an RPC that takes a stream of messages and produces one message.
+
+    Args:
+      response_callback: A callback to be called to accept the response message
+        of the RPC.
+      context: A face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Returns:
+      A stream.Consumer with which to accept the request messages of the RPC.
+        The consumer returned from this method may or may not be invoked to
+        completion: in the case of RPC abortion, RPC Framework will simply stop
+        passing messages to this object. Implementations must not assume that
+        this object will be called to completion of the request stream or even
+        called at all.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class StreamUnaryTestMessages(object):
+  """A type for stream-request-unary-response message pairings."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def requests(self):
+    """Affords a sequence of request messages.
+
+    Implementations of this method should return a different sequences with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A sequence of request messages.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, requests, response, test_case):
+    """Verifies that the computed response matches the given requests.
+
+    Args:
+      requests: A sequence of request messages.
+      response: A response message.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the requests and response do not match, indicating that
+        there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class StreamStreamTestMethodImplementation(test_interfaces.Method):
+  """A controllable implementation of a stream-stream method."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def service(self, response_consumer, context, control):
+    """Services an RPC that accepts and produces streams of messages.
+
+    Args:
+      response_consumer: A stream.Consumer to be called to accept the response
+        messages of the RPC.
+      context: A face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Returns:
+      A stream.Consumer with which to accept the request messages of the RPC.
+        The consumer returned from this method may or may not be invoked to
+        completion: in the case of RPC abortion, RPC Framework will simply stop
+        passing messages to this object. Implementations must not assume that
+        this object will be called to completion of the request stream or even
+        called at all.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class StreamStreamTestMessages(object):
+  """A type for stream-request-stream-response message pairings."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def requests(self):
+    """Affords a sequence of request messages.
+
+    Implementations of this method should return a different sequences with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A sequence of request messages.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, requests, responses, test_case):
+    """Verifies that the computed response matches the given requests.
+
+    Args:
+      requests: A sequence of request messages.
+      responses: A sequence of response messages.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the requests and responses do not match, indicating
+        that there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class TestService(object):
+  """A specification of implemented methods to use in tests."""
+
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def unary_unary_scenarios(self):
+    """Affords unary-request-unary-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a UnaryUnaryTestMethodImplementation object
+        and the second element is a sequence of UnaryUnaryTestMethodMessages
+        objects.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def unary_stream_scenarios(self):
+    """Affords unary-request-stream-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a UnaryStreamTestMethodImplementation
+        object and the second element is a sequence of
+        UnaryStreamTestMethodMessages objects.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stream_unary_scenarios(self):
+    """Affords stream-request-unary-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a StreamUnaryTestMethodImplementation
+        object and the second element is a sequence of
+        StreamUnaryTestMethodMessages objects.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stream_stream_scenarios(self):
+    """Affords stream-request-stream-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a StreamStreamTestMethodImplementation
+        object and the second element is a sequence of
+        StreamStreamTestMethodMessages objects.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/_stock_service.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_stock_service.py
new file mode 100644
index 0000000000..1dd2ec3633
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/_stock_service.py
@@ -0,0 +1,396 @@
+B# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Examples of Python implementations of the stock.proto Stock service."""
+
+from grpc.framework.common import cardinality
+from grpc.framework.foundation import abandonment
+from grpc.framework.foundation import stream
+from grpc_test.framework.common import test_constants
+from grpc_test.framework.interfaces.face import _service
+from grpc_test._junkdrawer import stock_pb2
+
+_STOCK_GROUP_NAME = 'Stock'
+_SYMBOL_FORMAT = 'test symbol:%03d'
+
+# A test-appropriate security-pricing function. :-P
+_price = lambda symbol_name: float(hash(symbol_name) % 4096)
+
+
+def _get_last_trade_price(stock_request, stock_reply_callback, control, active):
+  """A unary-request, unary-response test method."""
+  control.control()
+  if active():
+    stock_reply_callback(
+        stock_pb2.StockReply(
+            symbol=stock_request.symbol, price=_price(stock_request.symbol)))
+  else:
+    raise abandonment.Abandoned()
+
+
+def _get_last_trade_price_multiple(stock_reply_consumer, control, active):
+  """A stream-request, stream-response test method."""
+  def stock_reply_for_stock_request(stock_request):
+    control.control()
+    if active():
+      return stock_pb2.StockReply(
+          symbol=stock_request.symbol, price=_price(stock_request.symbol))
+    else:
+      raise abandonment.Abandoned()
+
+  class StockRequestConsumer(stream.Consumer):
+
+    def consume(self, stock_request):
+      stock_reply_consumer.consume(stock_reply_for_stock_request(stock_request))
+
+    def terminate(self):
+      control.control()
+      stock_reply_consumer.terminate()
+
+    def consume_and_terminate(self, stock_request):
+      stock_reply_consumer.consume_and_terminate(
+          stock_reply_for_stock_request(stock_request))
+
+  return StockRequestConsumer()
+
+
+def _watch_future_trades(stock_request, stock_reply_consumer, control, active):
+  """A unary-request, stream-response test method."""
+  base_price = _price(stock_request.symbol)
+  for index in range(stock_request.num_trades_to_watch):
+    control.control()
+    if active():
+      stock_reply_consumer.consume(
+          stock_pb2.StockReply(
+              symbol=stock_request.symbol, price=base_price + index))
+    else:
+      raise abandonment.Abandoned()
+  stock_reply_consumer.terminate()
+
+
+def _get_highest_trade_price(stock_reply_callback, control, active):
+  """A stream-request, unary-response test method."""
+
+  class StockRequestConsumer(stream.Consumer):
+    """Keeps an ongoing record of the most valuable symbol yet consumed."""
+
+    def __init__(self):
+      self._symbol = None
+      self._price = None
+
+    def consume(self, stock_request):
+      control.control()
+      if active():
+        if self._price is None:
+          self._symbol = stock_request.symbol
+          self._price = _price(stock_request.symbol)
+        else:
+          candidate_price = _price(stock_request.symbol)
+          if self._price < candidate_price:
+            self._symbol = stock_request.symbol
+            self._price = candidate_price
+
+    def terminate(self):
+      control.control()
+      if active():
+        if self._symbol is None:
+          raise ValueError()
+        else:
+          stock_reply_callback(
+              stock_pb2.StockReply(symbol=self._symbol, price=self._price))
+          self._symbol = None
+          self._price = None
+
+    def consume_and_terminate(self, stock_request):
+      control.control()
+      if active():
+        if self._price is None:
+          stock_reply_callback(
+              stock_pb2.StockReply(
+                  symbol=stock_request.symbol,
+                  price=_price(stock_request.symbol)))
+        else:
+          candidate_price = _price(stock_request.symbol)
+          if self._price < candidate_price:
+            stock_reply_callback(
+                stock_pb2.StockReply(
+                    symbol=stock_request.symbol, price=candidate_price))
+          else:
+            stock_reply_callback(
+                stock_pb2.StockReply(
+                    symbol=self._symbol, price=self._price))
+
+        self._symbol = None
+        self._price = None
+
+  return StockRequestConsumer()
+
+
+class GetLastTradePrice(_service.UnaryUnaryTestMethodImplementation):
+  """GetLastTradePrice for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'GetLastTradePrice'
+
+  def cardinality(self):
+    return cardinality.Cardinality.UNARY_UNARY
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, request, response_callback, context, control):
+    _get_last_trade_price(
+        request, response_callback, control, context.is_active)
+
+
+class GetLastTradePriceMessages(_service.UnaryUnaryTestMessages):
+
+  def __init__(self):
+    self._index = 0
+
+  def request(self):
+    symbol = _SYMBOL_FORMAT % self._index
+    self._index += 1
+    return stock_pb2.StockRequest(symbol=symbol)
+
+  def verify(self, request, response, test_case):
+    test_case.assertEqual(request.symbol, response.symbol)
+    test_case.assertEqual(_price(request.symbol), response.price)
+
+
+class GetLastTradePriceMultiple(_service.StreamStreamTestMethodImplementation):
+  """GetLastTradePriceMultiple for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'GetLastTradePriceMultiple'
+
+  def cardinality(self):
+    return cardinality.Cardinality.STREAM_STREAM
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, response_consumer, context, control):
+    return _get_last_trade_price_multiple(
+        response_consumer, control, context.is_active)
+
+
+class GetLastTradePriceMultipleMessages(_service.StreamStreamTestMessages):
+  """Pairs of message streams for use with GetLastTradePriceMultiple."""
+
+  def __init__(self):
+    self._index = 0
+
+  def requests(self):
+    base_index = self._index
+    self._index += 1
+    return [
+        stock_pb2.StockRequest(symbol=_SYMBOL_FORMAT % (base_index + index))
+        for index in range(test_constants.STREAM_LENGTH)]
+
+  def verify(self, requests, responses, test_case):
+    test_case.assertEqual(len(requests), len(responses))
+    for stock_request, stock_reply in zip(requests, responses):
+      test_case.assertEqual(stock_request.symbol, stock_reply.symbol)
+      test_case.assertEqual(_price(stock_request.symbol), stock_reply.price)
+
+
+class WatchFutureTrades(_service.UnaryStreamTestMethodImplementation):
+  """WatchFutureTrades for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'WatchFutureTrades'
+
+  def cardinality(self):
+    return cardinality.Cardinality.UNARY_STREAM
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, request, response_consumer, context, control):
+    _watch_future_trades(request, response_consumer, control, context.is_active)
+
+
+class WatchFutureTradesMessages(_service.UnaryStreamTestMessages):
+  """Pairs of a single request message and a sequence of response messages."""
+
+  def __init__(self):
+    self._index = 0
+
+  def request(self):
+    symbol = _SYMBOL_FORMAT % self._index
+    self._index += 1
+    return stock_pb2.StockRequest(
+        symbol=symbol, num_trades_to_watch=test_constants.STREAM_LENGTH)
+
+  def verify(self, request, responses, test_case):
+    test_case.assertEqual(test_constants.STREAM_LENGTH, len(responses))
+    base_price = _price(request.symbol)
+    for index, response in enumerate(responses):
+      test_case.assertEqual(base_price + index, response.price)
+
+
+class GetHighestTradePrice(_service.StreamUnaryTestMethodImplementation):
+  """GetHighestTradePrice for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'GetHighestTradePrice'
+
+  def cardinality(self):
+    return cardinality.Cardinality.STREAM_UNARY
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, response_callback, context, control):
+    return _get_highest_trade_price(
+        response_callback, control, context.is_active)
+
+
+class GetHighestTradePriceMessages(_service.StreamUnaryTestMessages):
+
+  def requests(self):
+    return [
+        stock_pb2.StockRequest(symbol=_SYMBOL_FORMAT % index)
+        for index in range(test_constants.STREAM_LENGTH)]
+
+  def verify(self, requests, response, test_case):
+    price = None
+    symbol = None
+    for stock_request in requests:
+      current_symbol = stock_request.symbol
+      current_price = _price(current_symbol)
+      if price is None or price < current_price:
+        price = current_price
+        symbol = current_symbol
+    test_case.assertEqual(price, response.price)
+    test_case.assertEqual(symbol, response.symbol)
+
+
+class StockTestService(_service.TestService):
+  """A corpus of test data with one method of each RPC cardinality."""
+
+  def unary_unary_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'GetLastTradePrice'): (
+            GetLastTradePrice(), [GetLastTradePriceMessages()]),
+    }
+
+  def unary_stream_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'WatchFutureTrades'): (
+            WatchFutureTrades(), [WatchFutureTradesMessages()]),
+    }
+
+  def stream_unary_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'GetHighestTradePrice'): (
+            GetHighestTradePrice(), [GetHighestTradePriceMessages()])
+    }
+
+  def stream_stream_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'GetLastTradePriceMultiple'): (
+            GetLastTradePriceMultiple(), [GetLastTradePriceMultipleMessages()]),
+    }
+
+
+STOCK_TEST_SERVICE = StockTestService()
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/test_cases.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/test_cases.py
new file mode 100644
index 0000000000..ca623662f7
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/test_cases.py
@@ -0,0 +1,67 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tools for creating tests of implementations of the Face layer."""
+
+# unittest is referenced from specification in this module.
+import unittest  # pylint: disable=unused-import
+
+# test_interfaces is referenced from specification in this module.
+from grpc_test.framework.interfaces.face import _blocking_invocation_inline_service
+from grpc_test.framework.interfaces.face import _event_invocation_synchronous_event_service
+from grpc_test.framework.interfaces.face import _future_invocation_asynchronous_event_service
+from grpc_test.framework.interfaces.face import _invocation
+from grpc_test.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+_TEST_CASE_SUPERCLASSES = (
+    _blocking_invocation_inline_service.TestCase,
+    _event_invocation_synchronous_event_service.TestCase,
+    _future_invocation_asynchronous_event_service.TestCase,
+)
+
+
+def test_cases(implementation):
+  """Creates unittest.TestCase classes for a given Face layer implementation.
+
+  Args:
+    implementation: A test_interfaces.Implementation specifying creation and
+      destruction of a given Face layer implementation.
+
+  Returns:
+    A sequence of subclasses of unittest.TestCase defining tests of the
+      specified Face layer implementation.
+  """
+  test_case_classes = []
+  for invoker_constructor in _invocation.invoker_constructors():
+    for super_class in _TEST_CASE_SUPERCLASSES:
+      test_case_classes.append(
+          type(invoker_constructor.name() + super_class.NAME, (super_class,),
+               {'implementation': implementation,
+                'invoker_constructor': invoker_constructor}))
+  return test_case_classes
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/face/test_interfaces.py b/src/python/grpcio_test/grpc_test/framework/interfaces/face/test_interfaces.py
new file mode 100644
index 0000000000..b2b5c10fa6
--- /dev/null
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/face/test_interfaces.py
@@ -0,0 +1,229 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Interfaces used in tests of implementations of the Face layer."""
+
+import abc
+
+from grpc.framework.common import cardinality  # pylint: disable=unused-import
+from grpc.framework.interfaces.face import face  # pylint: disable=unused-import
+
+
+class Method(object):
+  """Specifies a method to be used in tests."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def group(self):
+    """Identify the group of the method.
+
+    Returns:
+      The group of the method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def name(self):
+    """Identify the name of the method.
+
+    Returns:
+      The name of the method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def cardinality(self):
+    """Identify the cardinality of the method.
+
+    Returns:
+      A cardinality.Cardinality value describing the streaming semantics of the
+        method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def request_class(self):
+    """Identify the class used for the method's request objects.
+
+    Returns:
+      The class object of the class to which the method's request objects
+        belong.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def response_class(self):
+    """Identify the class used for the method's response objects.
+
+    Returns:
+      The class object of the class to which the method's response objects
+        belong.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_request(self, request):
+    """Serialize the given request object.
+
+    Args:
+      request: A request object appropriate for this method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_request(self, serialized_request):
+    """Synthesize a request object from a given bytestring.
+
+    Args:
+      serialized_request: A bytestring deserializable into a request object
+        appropriate for this method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_response(self, response):
+    """Serialize the given response object.
+
+    Args:
+      response: A response object appropriate for this method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_response(self, serialized_response):
+    """Synthesize a response object from a given bytestring.
+
+    Args:
+      serialized_response: A bytestring deserializable into a response object
+        appropriate for this method.
+    """
+    raise NotImplementedError()
+
+
+class Implementation(object):
+  """Specifies an implementation of the Face layer."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def instantiate(
+      self, methods, method_implementations,
+      multi_method_implementation):
+    """Instantiates the Face layer implementation to be used in a test.
+
+    Args:
+      methods: A sequence of Method objects describing the methods available to
+        be called during the test.
+      method_implementations: A dictionary from group-name pair to
+        face.MethodImplementation object specifying implementation of a method.
+      multi_method_implementation: A face.MultiMethodImplementation or None.
+
+    Returns:
+      A sequence of length three the first element of which is a
+        face.GenericStub, the second element of which is dictionary from groups
+        to face.DynamicStubs affording invocation of the group's methods, and
+        the third element of which is an arbitrary memo object to be kept and
+        passed to destantiate at the conclusion of the test. The returned stubs
+        must be backed by the provided implementations.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def destantiate(self, memo):
+    """Destroys the Face layer implementation under test.
+
+    Args:
+      memo: The object from the third position of the return value of a call to
+        instantiate.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_metadata(self):
+    """Provides the metadata to be used when invoking a test RPC.
+
+    Returns:
+      An object to use as the supplied-at-invocation-time metadata in a test
+        RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def initial_metadata(self):
+    """Provides the metadata for use as a test RPC's first servicer metadata.
+
+    Returns:
+      An object to use as the from-the-servicer-before-responses metadata in a
+        test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminal_metadata(self):
+    """Provides the metadata for use as a test RPC's second servicer metadata.
+
+    Returns:
+      An object to use as the from-the-servicer-after-all-responses metadata in
+        a test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def code(self):
+    """Provides the value for use as a test RPC's code.
+
+    Returns:
+      An object to use as the from-the-servicer code in a test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def details(self):
+    """Provides the value for use as a test RPC's details.
+
+    Returns:
+      An object to use as the from-the-servicer details in a test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    """Identifies whether or not metadata was properly transmitted.
+
+    Args:
+      original_metadata: A metadata value passed to the Face interface
+        implementation under test.
+      transmitted_metadata: The same metadata value after having been
+        transmitted via an RPC performed by the Face interface implementation
+          under test.
+
+    Returns:
+      Whether or not the metadata was properly transmitted by the Face interface
+        implementation under test.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_cases.py b/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_cases.py
index 1e575d1a9e..ecf49d9cdb 100644
--- a/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_cases.py
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_cases.py
@@ -300,7 +300,7 @@ class TransmissionTest(object):
         invocation_operation_id, 0, _TRANSMISSION_GROUP, _TRANSMISSION_METHOD,
         links.Ticket.Subscription.FULL, timeout, 0, invocation_initial_metadata,
         invocation_payload, invocation_terminal_metadata, invocation_code,
-        invocation_message, links.Ticket.Termination.COMPLETION)
+        invocation_message, links.Ticket.Termination.COMPLETION, None)
     self._invocation_link.accept_ticket(original_invocation_ticket)
 
     self._service_mate.block_until_tickets_satisfy(
@@ -317,7 +317,7 @@ class TransmissionTest(object):
         service_operation_id, 0, None, None, links.Ticket.Subscription.FULL,
         timeout, 0, service_initial_metadata, service_payload,
         service_terminal_metadata, service_code, service_message,
-        links.Ticket.Termination.COMPLETION)
+        links.Ticket.Termination.COMPLETION, None)
     self._service_link.accept_ticket(original_service_ticket)
     self._invocation_mate.block_until_tickets_satisfy(terminated)
     self._assert_is_valid_service_sequence(
diff --git a/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_utilities.py b/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_utilities.py
index 6c2e3346aa..39c7f2fc63 100644
--- a/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_utilities.py
+++ b/src/python/grpcio_test/grpc_test/framework/interfaces/links/test_utilities.py
@@ -29,9 +29,42 @@
 
 """State and behavior appropriate for use in tests."""
 
+import logging
 import threading
+import time
 
 from grpc.framework.interfaces.links import links
+from grpc.framework.interfaces.links import utilities
+
+# A more-or-less arbitrary limit on the length of raw data values to be logged.
+_UNCOMFORTABLY_LONG = 48
+
+
+def _safe_for_log_ticket(ticket):
+  """Creates a safe-for-printing-to-the-log ticket for a given ticket.
+
+  Args:
+    ticket: Any links.Ticket.
+
+  Returns:
+    A links.Ticket that is as much as can be equal to the given ticket but
+      possibly features values like the string "<payload of length 972321>" in
+      place of the actual values of the given ticket.
+  """
+  if isinstance(ticket.payload, (basestring,)):
+    payload_length = len(ticket.payload)
+  else:
+    payload_length = -1
+  if payload_length < _UNCOMFORTABLY_LONG:
+    return ticket
+  else:
+    return links.Ticket(
+        ticket.operation_id, ticket.sequence_number,
+        ticket.group, ticket.method, ticket.subscription, ticket.timeout,
+        ticket.allowance, ticket.initial_metadata,
+        '<payload of length {}>'.format(payload_length),
+        ticket.terminal_metadata, ticket.code, ticket.message,
+        ticket.termination, None)
 
 
 class RecordingLink(links.Link):
@@ -64,3 +97,71 @@ class RecordingLink(links.Link):
     """Returns a copy of the list of all tickets received by this Link."""
     with self._condition:
       return tuple(self._tickets)
+
+
+class _Pipe(object):
+  """A conduit that logs all tickets passed through it."""
+
+  def __init__(self, name):
+    self._lock = threading.Lock()
+    self._name = name
+    self._left_mate = utilities.NULL_LINK
+    self._right_mate = utilities.NULL_LINK
+
+  def accept_left_to_right_ticket(self, ticket):
+    with self._lock:
+      logging.warning(
+          '%s: moving left to right through %s: %s', time.time(), self._name,
+          _safe_for_log_ticket(ticket))
+      try:
+        self._right_mate.accept_ticket(ticket)
+      except Exception as e:  # pylint: disable=broad-except
+        logging.exception(e)
+
+  def accept_right_to_left_ticket(self, ticket):
+    with self._lock:
+      logging.warning(
+          '%s: moving right to left through %s: %s', time.time(), self._name,
+          _safe_for_log_ticket(ticket))
+      try:
+        self._left_mate.accept_ticket(ticket)
+      except Exception as e:  # pylint: disable=broad-except
+        logging.exception(e)
+
+  def join_left_mate(self, left_mate):
+    with self._lock:
+      self._left_mate = utilities.NULL_LINK if left_mate is None else left_mate
+
+  def join_right_mate(self, right_mate):
+    with self._lock:
+      self._right_mate = (
+          utilities.NULL_LINK if right_mate is None else right_mate)
+
+
+class _Facade(links.Link):
+
+  def __init__(self, accept, join):
+    self._accept = accept
+    self._join = join
+
+  def accept_ticket(self, ticket):
+    self._accept(ticket)
+
+  def join_link(self, link):
+    self._join(link)
+
+
+def logging_links(name):
+  """Creates a conduit that logs all tickets passed through it.
+
+  Args:
+    name: A name to use for the conduit to identify itself in logging output.
+
+  Returns:
+    Two links.Links, the first of which is the "left" side of the conduit
+      and the second of which is the "right" side of the conduit.
+  """
+  pipe = _Pipe(name)
+  left_facade = _Facade(pipe.accept_left_to_right_ticket, pipe.join_left_mate)
+  right_facade = _Facade(pipe.accept_right_to_left_ticket, pipe.join_right_mate)
+  return left_facade, right_facade
diff --git a/src/python/grpcio_test/setup.py b/src/python/grpcio_test/setup.py
index a6203cae2d..898ea204ac 100644
--- a/src/python/grpcio_test/setup.py
+++ b/src/python/grpcio_test/setup.py
@@ -61,6 +61,7 @@ _SETUP_REQUIRES = (
     'pytest>=2.6',
     'pytest-cov>=2.0',
     'pytest-xdist>=1.11',
+    'pytest-timeout>=0.5',
 )
 
 _INSTALL_REQUIRES = (
diff --git a/src/ruby/.rspec b/src/ruby/.rspec
index cd7c5fb5b2..2320752db4 100755
--- a/src/ruby/.rspec
+++ b/src/ruby/.rspec
@@ -1,4 +1,5 @@
 -I.
+-Ipb
 --require spec_helper
 --format documentation
 --color
diff --git a/src/ruby/.rubocop.yml b/src/ruby/.rubocop.yml
index 47e382afa7..312bdca384 100644
--- a/src/ruby/.rubocop.yml
+++ b/src/ruby/.rubocop.yml
@@ -5,6 +5,7 @@ inherit_from: .rubocop_todo.yml
 AllCops:
   Exclude:
     - 'bin/apis/**/*'
-    - 'bin/interop/test/**/*'
     - 'bin/math.rb'
     - 'bin/math_services.rb'
+    - 'pb/grpc/health/v1alpha/*'
+    - 'pb/test/**/*'
diff --git a/src/ruby/README.md b/src/ruby/README.md
index 4b657c0bd4..f8902e34c5 100644
--- a/src/ruby/README.md
+++ b/src/ruby/README.md
@@ -12,12 +12,36 @@ PREREQUISITES
 -------------
 
 - Ruby 2.x. The gRPC API uses keyword args.
-- [homebrew][] on Mac OS X, [linuxbrew][] on Linux.  These simplify the installation of the gRPC C core.
+- [homebrew][] on Mac OS X.  These simplify the installation of the gRPC C core.
 
 INSTALLATION
 ---------------
-On Mac OS X, install [homebrew][]. On Linux, install [linuxbrew][].
-Run the following command to install gRPC Ruby.
+
+**Linux (Debian):**
+
+Add [Debian unstable][] to your `sources.list` file. Example:
+
+```sh
+echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+sudo tee -a /etc/apt/sources.list
+```
+
+Install the gRPC Debian package
+
+```sh
+sudo apt-get update
+sudo apt-get install libgrpc-dev
+```
+
+Install the gRPC Ruby package
+
+```sh
+gem install grpc
+```
+
+**Mac OS X**
+
+Install [homebrew][]. Run the following command to install gRPC Ruby.
 ```sh
 $ curl -fsSL https://goo.gl/getgrpc | bash -s ruby
 ```
@@ -26,12 +50,6 @@ This will download and run the [gRPC install script][], then install the latest
 BUILD FROM SOURCE
 ---------------------
 - Clone this repository
-- Build the gRPC C core
-E.g, from the root of the gRPC [Git repository](https://github.com/google/grpc)
-```sh
-$ cd ../..
-$ make && sudo make install
-```
 
 - Install Ruby 2.x. Consider doing this with [RVM](http://rvm.io), it's a nice way of controlling
   the exact ruby version that's used.
@@ -77,8 +95,8 @@ Directory structure is the layout for [ruby extensions][]
   GRPC.logger.info("Answer: #{resp.inspect}")
   ```
 [homebrew]:http://brew.sh
-[linuxbrew]:https://github.com/Homebrew/linuxbrew#installation
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
 [ruby extensions]:http://guides.rubygems.org/gems-with-extensions/
 [rubydoc]: http://www.rubydoc.info/gems/grpc
 [grpc.io]: http://www.grpc.io/docs/installation/ruby.html
+[Debian unstable]:https://www.debian.org/releases/sid/
diff --git a/src/ruby/Rakefile b/src/ruby/Rakefile
index 02af9a84b8..cc7832b12d 100755
--- a/src/ruby/Rakefile
+++ b/src/ruby/Rakefile
@@ -20,7 +20,8 @@ SPEC_SUITES = [
   { id: :bidi, title: 'bidi tests', dir: %w(spec/generic),
     tag: 'bidi' },
   { id: :server, title: 'rpc server thread tests', dir: %w(spec/generic),
-    tag: 'server' }
+    tag: 'server' },
+  { id: :pb, title: 'protobuf service tests', dir: %w(spec/pb) }
 ]
 namespace :suite do
   SPEC_SUITES.each do |suite|
@@ -50,7 +51,8 @@ task 'suite:wrapper' => [:compile, :rubocop]
 task 'suite:idiomatic' => 'suite:wrapper'
 task 'suite:bidi' => 'suite:wrapper'
 task 'suite:server' => 'suite:wrapper'
+task 'suite:pb' => 'suite:server'
 
 desc 'Compiles the gRPC extension then runs all the tests'
-task all: ['suite:idiomatic', 'suite:bidi', 'suite:server']
+task all: ['suite:idiomatic', 'suite:bidi', 'suite:pb', 'suite:server']
 task default: :all
diff --git a/src/ruby/bin/grpc_ruby_interop_client b/src/ruby/bin/grpc_ruby_interop_client
new file mode 100755
index 0000000000..e79fd33aa5
--- /dev/null
+++ b/src/ruby/bin/grpc_ruby_interop_client
@@ -0,0 +1,33 @@
+#!/usr/bin/env ruby
+
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# Provides a gem binary entry point for the interop client.
+require 'test/client'
diff --git a/src/ruby/bin/grpc_ruby_interop_server b/src/ruby/bin/grpc_ruby_interop_server
new file mode 100755
index 0000000000..656a5f7c99
--- /dev/null
+++ b/src/ruby/bin/grpc_ruby_interop_server
@@ -0,0 +1,33 @@
+#!/usr/bin/env ruby
+
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# Provides a gem binary entry point for the interop server
+require 'test/server'
diff --git a/src/ruby/bin/interop/README.md b/src/ruby/bin/interop/README.md
deleted file mode 100644
index 84fc663620..0000000000
--- a/src/ruby/bin/interop/README.md
+++ /dev/null
@@ -1,8 +0,0 @@
-Interop test protos
-===================
-
-These ruby classes were generated with protoc v3, using grpc's ruby compiler
-plugin.
-
-- As of 2015/01 protoc v3 is available in the
-[google-protobuf](https://github.com/google/protobuf) repo
diff --git a/src/ruby/bin/interop/interop_client.rb b/src/ruby/bin/interop/interop_client.rb
index da4caa842b..239083f37f 100755
--- a/src/ruby/bin/interop/interop_client.rb
+++ b/src/ruby/bin/interop/interop_client.rb
@@ -29,6 +29,12 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+# #######################################################################
+# DEPRECATED: The behaviour in this file has been moved to pb/test/client.rb
+#
+# This file remains to support existing tools and scripts that use it.
+# ######################################################################
+#
 # interop_client is a testing tool that accesses a gRPC interop testing
 # server and runs a test on it.
 #
@@ -39,339 +45,7 @@
 #                                    --test_case=<testcase_name>
 
 this_dir = File.expand_path(File.dirname(__FILE__))
-lib_dir = File.join(File.dirname(File.dirname(this_dir)), 'lib')
-$LOAD_PATH.unshift(lib_dir) unless $LOAD_PATH.include?(lib_dir)
-$LOAD_PATH.unshift(this_dir) unless $LOAD_PATH.include?(this_dir)
-
-require 'optparse'
-require 'minitest'
-require 'minitest/assertions'
-
-require 'grpc'
-require 'googleauth'
-require 'google/protobuf'
-
-require 'test/cpp/interop/test_services'
-require 'test/cpp/interop/messages'
-require 'test/cpp/interop/empty'
-
-require 'signet/ssl_config'
-
-AUTH_ENV = Google::Auth::CredentialsLoader::ENV_VAR
-
-# loads the certificates used to access the test server securely.
-def load_test_certs
-  this_dir = File.expand_path(File.dirname(__FILE__))
-  data_dir = File.join(File.dirname(File.dirname(this_dir)), 'spec/testdata')
-  files = ['ca.pem', 'server1.key', 'server1.pem']
-  files.map { |f| File.open(File.join(data_dir, f)).read }
-end
-
-# loads the certificates used to access the test server securely.
-def load_prod_cert
-  fail 'could not find a production cert' if ENV['SSL_CERT_FILE'].nil?
-  GRPC.logger.info("loading prod certs from #{ENV['SSL_CERT_FILE']}")
-  File.open(ENV['SSL_CERT_FILE']).read
-end
-
-# creates SSL Credentials from the test certificates.
-def test_creds
-  certs = load_test_certs
-  GRPC::Core::Credentials.new(certs[0])
-end
-
-# creates SSL Credentials from the production certificates.
-def prod_creds
-  cert_text = load_prod_cert
-  GRPC::Core::Credentials.new(cert_text)
-end
-
-# creates the SSL Credentials.
-def ssl_creds(use_test_ca)
-  return test_creds if use_test_ca
-  prod_creds
-end
-
-# creates a test stub that accesses host:port securely.
-def create_stub(opts)
-  address = "#{opts.host}:#{opts.port}"
-  if opts.secure
-    stub_opts = {
-      :creds => ssl_creds(opts.use_test_ca),
-      GRPC::Core::Channel::SSL_TARGET => opts.host_override
-    }
-
-    # Add service account creds if specified
-    wants_creds = %w(all compute_engine_creds service_account_creds)
-    if wants_creds.include?(opts.test_case)
-      unless opts.oauth_scope.nil?
-        auth_creds = Google::Auth.get_application_default(opts.oauth_scope)
-        stub_opts[:update_metadata] = auth_creds.updater_proc
-      end
-    end
-
-    if opts.test_case == 'jwt_token_creds'  # don't use a scope
-      auth_creds = Google::Auth.get_application_default
-      stub_opts[:update_metadata] = auth_creds.updater_proc
-    end
-
-    GRPC.logger.info("... connecting securely to #{address}")
-    Grpc::Testing::TestService::Stub.new(address, **stub_opts)
-  else
-    GRPC.logger.info("... connecting insecurely to #{address}")
-    Grpc::Testing::TestService::Stub.new(address)
-  end
-end
-
-# produces a string of null chars (\0) of length l.
-def nulls(l)
-  fail 'requires #{l} to be +ve' if l < 0
-  [].pack('x' * l).force_encoding('utf-8')
-end
-
-# a PingPongPlayer implements the ping pong bidi test.
-class PingPongPlayer
-  include Minitest::Assertions
-  include Grpc::Testing
-  include Grpc::Testing::PayloadType
-  attr_accessor :assertions # required by Minitest::Assertions
-  attr_accessor :queue
-  attr_accessor :canceller_op
-
-  # reqs is the enumerator over the requests
-  def initialize(msg_sizes)
-    @queue = Queue.new
-    @msg_sizes = msg_sizes
-    @assertions = 0  # required by Minitest::Assertions
-    @canceller_op = nil  # used to cancel after the first response
-  end
-
-  def each_item
-    return enum_for(:each_item) unless block_given?
-    req_cls, p_cls = StreamingOutputCallRequest, ResponseParameters  # short
-    count = 0
-    @msg_sizes.each do |m|
-      req_size, resp_size = m
-      req = req_cls.new(payload: Payload.new(body: nulls(req_size)),
-                        response_type: :COMPRESSABLE,
-                        response_parameters: [p_cls.new(size: resp_size)])
-      yield req
-      resp = @queue.pop
-      assert_equal(:COMPRESSABLE, resp.payload.type, 'payload type is wrong')
-      assert_equal(resp_size, resp.payload.body.length,
-                   "payload body #{count} has the wrong length")
-      p "OK: ping_pong #{count}"
-      count += 1
-      unless @canceller_op.nil?
-        canceller_op.cancel
-        break
-      end
-    end
-  end
-end
-
-# defines methods corresponding to each interop test case.
-class NamedTests
-  include Minitest::Assertions
-  include Grpc::Testing
-  include Grpc::Testing::PayloadType
-  attr_accessor :assertions # required by Minitest::Assertions
-
-  def initialize(stub, args)
-    @assertions = 0  # required by Minitest::Assertions
-    @stub = stub
-    @args = args
-  end
-
-  def empty_unary
-    resp = @stub.empty_call(Empty.new)
-    assert resp.is_a?(Empty), 'empty_unary: invalid response'
-    p 'OK: empty_unary'
-  end
-
-  def large_unary
-    perform_large_unary
-    p 'OK: large_unary'
-  end
-
-  def service_account_creds
-    # ignore this test if the oauth options are not set
-    if @args.oauth_scope.nil?
-      p 'NOT RUN: service_account_creds; no service_account settings'
-      return
-    end
-    json_key = File.read(ENV[AUTH_ENV])
-    wanted_email = MultiJson.load(json_key)['client_email']
-    resp = perform_large_unary(fill_username: true,
-                               fill_oauth_scope: true)
-    assert_equal(wanted_email, resp.username,
-                 'service_account_creds: incorrect username')
-    assert(@args.oauth_scope.include?(resp.oauth_scope),
-           'service_account_creds: incorrect oauth_scope')
-    p 'OK: service_account_creds'
-  end
-
-  def jwt_token_creds
-    json_key = File.read(ENV[AUTH_ENV])
-    wanted_email = MultiJson.load(json_key)['client_email']
-    resp = perform_large_unary(fill_username: true)
-    assert_equal(wanted_email, resp.username,
-                 'service_account_creds: incorrect username')
-    p 'OK: jwt_token_creds'
-  end
-
-  def compute_engine_creds
-    resp = perform_large_unary(fill_username: true,
-                               fill_oauth_scope: true)
-    assert_equal(@args.default_service_account, resp.username,
-                 'compute_engine_creds: incorrect username')
-    p 'OK: compute_engine_creds'
-  end
-
-  def client_streaming
-    msg_sizes = [27_182, 8, 1828, 45_904]
-    wanted_aggregate_size = 74_922
-    reqs = msg_sizes.map do |x|
-      req = Payload.new(body: nulls(x))
-      StreamingInputCallRequest.new(payload: req)
-    end
-    resp = @stub.streaming_input_call(reqs)
-    assert_equal(wanted_aggregate_size, resp.aggregated_payload_size,
-                 'client_streaming: aggregate payload size is incorrect')
-    p 'OK: client_streaming'
-  end
-
-  def server_streaming
-    msg_sizes = [31_415, 9, 2653, 58_979]
-    response_spec = msg_sizes.map { |s| ResponseParameters.new(size: s) }
-    req = StreamingOutputCallRequest.new(response_type: :COMPRESSABLE,
-                                         response_parameters: response_spec)
-    resps = @stub.streaming_output_call(req)
-    resps.each_with_index do |r, i|
-      assert i < msg_sizes.length, 'too many responses'
-      assert_equal(:COMPRESSABLE, r.payload.type,
-                   'payload type is wrong')
-      assert_equal(msg_sizes[i], r.payload.body.length,
-                   'payload body #{i} has the wrong length')
-    end
-    p 'OK: server_streaming'
-  end
-
-  def ping_pong
-    msg_sizes = [[27_182, 31_415], [8, 9], [1828, 2653], [45_904, 58_979]]
-    ppp = PingPongPlayer.new(msg_sizes)
-    resps = @stub.full_duplex_call(ppp.each_item)
-    resps.each { |r| ppp.queue.push(r) }
-    p 'OK: ping_pong'
-  end
-
-  def cancel_after_begin
-    msg_sizes = [27_182, 8, 1828, 45_904]
-    reqs = msg_sizes.map do |x|
-      req = Payload.new(body: nulls(x))
-      StreamingInputCallRequest.new(payload: req)
-    end
-    op = @stub.streaming_input_call(reqs, return_op: true)
-    op.cancel
-    assert_raises(GRPC::Cancelled) { op.execute }
-    assert(op.cancelled, 'call operation should be CANCELLED')
-    p 'OK: cancel_after_begin'
-  end
-
-  def cancel_after_first_response
-    msg_sizes = [[27_182, 31_415], [8, 9], [1828, 2653], [45_904, 58_979]]
-    ppp = PingPongPlayer.new(msg_sizes)
-    op = @stub.full_duplex_call(ppp.each_item, return_op: true)
-    ppp.canceller_op = op  # causes ppp to cancel after the 1st message
-    op.execute.each { |r| ppp.queue.push(r) }
-    op.wait
-    assert(op.cancelled, 'call operation was not CANCELLED')
-    p 'OK: cancel_after_first_response'
-  end
-
-  def all
-    all_methods = NamedTests.instance_methods(false).map(&:to_s)
-    all_methods.each do |m|
-      next if m == 'all' || m.start_with?('assert')
-      p "TESTCASE: #{m}"
-      method(m).call
-    end
-  end
-
-  private
-
-  def perform_large_unary(fill_username: false, fill_oauth_scope: false)
-    req_size, wanted_response_size = 271_828, 314_159
-    payload = Payload.new(type: :COMPRESSABLE, body: nulls(req_size))
-    req = SimpleRequest.new(response_type: :COMPRESSABLE,
-                            response_size: wanted_response_size,
-                            payload: payload)
-    req.fill_username = fill_username
-    req.fill_oauth_scope = fill_oauth_scope
-    resp = @stub.unary_call(req)
-    assert_equal(:COMPRESSABLE, resp.payload.type,
-                 'large_unary: payload had the wrong type')
-    assert_equal(wanted_response_size, resp.payload.body.length,
-                 'large_unary: payload had the wrong length')
-    assert_equal(nulls(wanted_response_size), resp.payload.body,
-                 'large_unary: payload content is invalid')
-    resp
-  end
-end
-
-# Args is used to hold the command line info.
-Args = Struct.new(:default_service_account, :host, :host_override,
-                  :oauth_scope, :port, :secure, :test_case,
-                  :use_test_ca)
-
-# validates the the command line options, returning them as a Hash.
-def parse_args
-  args = Args.new
-  args.host_override = 'foo.test.google.fr'
-  OptionParser.new do |opts|
-    opts.on('--oauth_scope scope',
-            'Scope for OAuth tokens') { |v| args['oauth_scope'] = v }
-    opts.on('--server_host SERVER_HOST', 'server hostname') do |v|
-      args['host'] = v
-    end
-    opts.on('--default_service_account email_address',
-            'email address of the default service account') do |v|
-      args['default_service_account'] = v
-    end
-    opts.on('--server_host_override HOST_OVERRIDE',
-            'override host via a HTTP header') do |v|
-      args['host_override'] = v
-    end
-    opts.on('--server_port SERVER_PORT', 'server port') { |v| args['port'] = v }
-    # instance_methods(false) gives only the methods defined in that class
-    test_cases = NamedTests.instance_methods(false).map(&:to_s)
-    test_case_list = test_cases.join(',')
-    opts.on('--test_case CODE', test_cases, {}, 'select a test_case',
-            "  (#{test_case_list})") { |v| args['test_case'] = v }
-    opts.on('-s', '--use_tls', 'require a secure connection?') do |v|
-      args['secure'] = v
-    end
-    opts.on('-t', '--use_test_ca',
-            'if secure, use the test certificate?') do |v|
-      args['use_test_ca'] = v
-    end
-  end.parse!
-  _check_args(args)
-end
-
-def _check_args(args)
-  %w(host port test_case).each do |a|
-    if args[a].nil?
-      fail(OptionParser::MissingArgument, "please specify --#{arg}")
-    end
-  end
-  args
-end
-
-def main
-  opts = parse_args
-  stub = create_stub(opts)
-  NamedTests.new(stub, opts).method(opts['test_case']).call
-end
+pb_dir = File.join(File.dirname(File.dirname(this_dir)), 'pb')
+$LOAD_PATH.unshift(pb_dir) unless $LOAD_PATH.include?(pb_dir)
 
-main
+require 'test/client'
diff --git a/src/ruby/bin/interop/interop_server.rb b/src/ruby/bin/interop/interop_server.rb
index 2ba8d2c19e..c6b0d00ec6 100755
--- a/src/ruby/bin/interop/interop_server.rb
+++ b/src/ruby/bin/interop/interop_server.rb
@@ -29,6 +29,12 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+# #######################################################################
+# DEPRECATED: The behaviour in this file has been moved to pb/test/server.rb
+#
+# This file remains to support existing tools and scripts that use it.
+# ######################################################################
+#
 # interop_server is a Testing app that runs a gRPC interop testing server.
 #
 # It helps validate interoperation b/w gRPC in different environments
@@ -38,157 +44,7 @@
 # Usage: $ path/to/interop_server.rb --port
 
 this_dir = File.expand_path(File.dirname(__FILE__))
-lib_dir = File.join(File.dirname(File.dirname(this_dir)), 'lib')
-$LOAD_PATH.unshift(lib_dir) unless $LOAD_PATH.include?(lib_dir)
-$LOAD_PATH.unshift(this_dir) unless $LOAD_PATH.include?(this_dir)
-
-require 'forwardable'
-require 'optparse'
-
-require 'grpc'
-
-require 'test/cpp/interop/test_services'
-require 'test/cpp/interop/messages'
-require 'test/cpp/interop/empty'
-
-# loads the certificates by the test server.
-def load_test_certs
-  this_dir = File.expand_path(File.dirname(__FILE__))
-  data_dir = File.join(File.dirname(File.dirname(this_dir)), 'spec/testdata')
-  files = ['ca.pem', 'server1.key', 'server1.pem']
-  files.map { |f| File.open(File.join(data_dir, f)).read }
-end
-
-# creates a ServerCredentials from the test certificates.
-def test_server_creds
-  certs = load_test_certs
-  GRPC::Core::ServerCredentials.new(nil, certs[1], certs[2])
-end
-
-# produces a string of null chars (\0) of length l.
-def nulls(l)
-  fail 'requires #{l} to be +ve' if l < 0
-  [].pack('x' * l).force_encoding('utf-8')
-end
-
-# A EnumeratorQueue wraps a Queue yielding the items added to it via each_item.
-class EnumeratorQueue
-  extend Forwardable
-  def_delegators :@q, :push
-
-  def initialize(sentinel)
-    @q = Queue.new
-    @sentinel = sentinel
-  end
-
-  def each_item
-    return enum_for(:each_item) unless block_given?
-    loop do
-      r = @q.pop
-      break if r.equal?(@sentinel)
-      fail r if r.is_a? Exception
-      yield r
-    end
-  end
-end
-
-# A runnable implementation of the schema-specified testing service, with each
-# service method implemented as required by the interop testing spec.
-class TestTarget < Grpc::Testing::TestService::Service
-  include Grpc::Testing
-  include Grpc::Testing::PayloadType
-
-  def empty_call(_empty, _call)
-    Empty.new
-  end
-
-  def unary_call(simple_req, _call)
-    req_size = simple_req.response_size
-    SimpleResponse.new(payload: Payload.new(type: :COMPRESSABLE,
-                                            body: nulls(req_size)))
-  end
-
-  def streaming_input_call(call)
-    sizes = call.each_remote_read.map { |x| x.payload.body.length }
-    sum = sizes.inject { |s, x| s + x }
-    StreamingInputCallResponse.new(aggregated_payload_size: sum)
-  end
-
-  def streaming_output_call(req, _call)
-    cls = StreamingOutputCallResponse
-    req.response_parameters.map do |p|
-      cls.new(payload: Payload.new(type: req.response_type,
-                                   body: nulls(p.size)))
-    end
-  end
-
-  def full_duplex_call(reqs)
-    # reqs is a lazy Enumerator of the requests sent by the client.
-    q = EnumeratorQueue.new(self)
-    cls = StreamingOutputCallResponse
-    Thread.new do
-      begin
-        GRPC.logger.info('interop-server: started receiving')
-        reqs.each do |req|
-          resp_size = req.response_parameters[0].size
-          GRPC.logger.info("read a req, response size is #{resp_size}")
-          resp = cls.new(payload: Payload.new(type: req.response_type,
-                                              body: nulls(resp_size)))
-          q.push(resp)
-        end
-        GRPC.logger.info('interop-server: finished receiving')
-        q.push(self)
-      rescue StandardError => e
-        GRPC.logger.info('interop-server: failed')
-        GRPC.logger.warn(e)
-        q.push(e)  # share the exception with the enumerator
-      end
-    end
-    q.each_item
-  end
-
-  def half_duplex_call(reqs)
-    # TODO: update with unique behaviour of the half_duplex_call if that's
-    # ever required by any of the tests.
-    full_duplex_call(reqs)
-  end
-end
-
-# validates the the command line options, returning them as a Hash.
-def parse_options
-  options = {
-    'port' => nil,
-    'secure' => false
-  }
-  OptionParser.new do |opts|
-    opts.banner = 'Usage: --port port'
-    opts.on('--port PORT', 'server port') do |v|
-      options['port'] = v
-    end
-    opts.on('-s', '--use_tls', 'require a secure connection?') do |v|
-      options['secure'] = v
-    end
-  end.parse!
-
-  if options['port'].nil?
-    fail(OptionParser::MissingArgument, 'please specify --port')
-  end
-  options
-end
-
-def main
-  opts = parse_options
-  host = "0.0.0.0:#{opts['port']}"
-  s = GRPC::RpcServer.new
-  if opts['secure']
-    s.add_http2_port(host, test_server_creds)
-    GRPC.logger.info("... running securely on #{host}")
-  else
-    s.add_http2_port(host)
-    GRPC.logger.info("... running insecurely on #{host}")
-  end
-  s.handle(TestTarget)
-  s.run_till_terminated
-end
+pb_dir = File.join(File.dirname(File.dirname(this_dir)), 'pb')
+$LOAD_PATH.unshift(pb_dir) unless $LOAD_PATH.include?(pb_dir)
 
-main
+require 'test/server'
diff --git a/src/ruby/ext/grpc/rb_call.c b/src/ruby/ext/grpc/rb_call.c
index 70f0795f29..6b5beb6f5d 100644
--- a/src/ruby/ext/grpc/rb_call.c
+++ b/src/ruby/ext/grpc/rb_call.c
@@ -82,6 +82,10 @@ static ID id_metadata;
  * received by the call and subsequently saved on it. */
 static ID id_status;
 
+/* id_write_flag is name of the attribute used to access the write_flag
+ * saved on the call. */
+static ID id_write_flag;
+
 /* sym_* are the symbol for attributes of grpc_rb_sBatchResult. */
 static VALUE sym_send_message;
 static VALUE sym_send_metadata;
@@ -240,6 +244,30 @@ static VALUE grpc_rb_call_set_metadata(VALUE self, VALUE metadata) {
   return rb_ivar_set(self, id_metadata, metadata);
 }
 
+/*
+  call-seq:
+  write_flag = call.write_flag
+
+  Gets the write_flag value saved the call.  */
+static VALUE grpc_rb_call_get_write_flag(VALUE self) {
+  return rb_ivar_get(self, id_write_flag);
+}
+
+/*
+  call-seq:
+  call.write_flag = write_flag
+
+  Saves the write_flag on the call.  */
+static VALUE grpc_rb_call_set_write_flag(VALUE self, VALUE write_flag) {
+  if (!NIL_P(write_flag) && TYPE(write_flag) != T_FIXNUM) {
+    rb_raise(rb_eTypeError, "bad write_flag: got:<%s> want: <Fixnum>",
+             rb_obj_classname(write_flag));
+    return Qnil;
+  }
+
+  return rb_ivar_set(self, id_write_flag, write_flag);
+}
+
 /* grpc_rb_md_ary_fill_hash_cb is the hash iteration callback used
    to fill grpc_metadata_array.
 
@@ -437,17 +465,19 @@ typedef struct run_batch_stack {
   grpc_status_code recv_status;
   char *recv_status_details;
   size_t recv_status_details_capacity;
+  uint write_flag;
 } run_batch_stack;
 
 /* grpc_run_batch_stack_init ensures the run_batch_stack is properly
  * initialized */
-static void grpc_run_batch_stack_init(run_batch_stack *st) {
+static void grpc_run_batch_stack_init(run_batch_stack *st, uint write_flag) {
   MEMZERO(st, run_batch_stack, 1);
   grpc_metadata_array_init(&st->send_metadata);
   grpc_metadata_array_init(&st->send_trailing_metadata);
   grpc_metadata_array_init(&st->recv_metadata);
   grpc_metadata_array_init(&st->recv_trailing_metadata);
   st->op_num = 0;
+  st->write_flag = write_flag;
 }
 
 /* grpc_run_batch_stack_cleanup ensures the run_batch_stack is properly
@@ -477,6 +507,7 @@ static void grpc_run_batch_stack_fill_ops(run_batch_stack *st, VALUE ops_hash) {
   for (i = 0; i < (size_t)RARRAY_LEN(ops_ary); i++) {
     this_op = rb_ary_entry(ops_ary, i);
     this_value = rb_hash_aref(ops_hash, this_op);
+    st->ops[st->op_num].flags = 0;
     switch (NUM2INT(this_op)) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         /* N.B. later there is no need to explicitly delete the metadata keys
@@ -490,6 +521,7 @@ static void grpc_run_batch_stack_fill_ops(run_batch_stack *st, VALUE ops_hash) {
       case GRPC_OP_SEND_MESSAGE:
         st->ops[st->op_num].data.send_message = grpc_rb_s_to_byte_buffer(
             RSTRING_PTR(this_value), RSTRING_LEN(this_value));
+        st->ops[st->op_num].flags = st->write_flag;
         break;
       case GRPC_OP_SEND_CLOSE_FROM_CLIENT:
         break;
@@ -525,7 +557,7 @@ static void grpc_run_batch_stack_fill_ops(run_batch_stack *st, VALUE ops_hash) {
                  NUM2INT(this_op));
     };
     st->ops[st->op_num].op = (grpc_op_type)NUM2INT(this_op);
-    st->ops[st->op_num].flags = 0;
+    st->ops[st->op_num].reserved = NULL;
     st->op_num++;
   }
 }
@@ -603,6 +635,8 @@ static VALUE grpc_rb_call_run_batch(VALUE self, VALUE cqueue, VALUE tag,
   grpc_event ev;
   grpc_call_error err;
   VALUE result = Qnil;
+  VALUE rb_write_flag = rb_ivar_get(self, id_write_flag);
+  uint write_flag = 0;
   TypedData_Get_Struct(self, grpc_call, &grpc_call_data_type, call);
 
   /* Validate the ops args, adding them to a ruby array */
@@ -610,7 +644,10 @@ static VALUE grpc_rb_call_run_batch(VALUE self, VALUE cqueue, VALUE tag,
     rb_raise(rb_eTypeError, "call#run_batch: ops hash should be a hash");
     return Qnil;
   }
-  grpc_run_batch_stack_init(&st);
+  if (rb_write_flag != Qnil) {
+    write_flag = NUM2UINT(rb_write_flag);
+  }
+  grpc_run_batch_stack_init(&st, write_flag);
   grpc_run_batch_stack_fill_ops(&st, ops_hash);
 
   /* call grpc_call_start_batch, then wait for it to complete using
@@ -629,18 +666,24 @@ static VALUE grpc_rb_call_run_batch(VALUE self, VALUE cqueue, VALUE tag,
     rb_raise(grpc_rb_eOutOfTime, "grpc_call_start_batch timed out");
     return Qnil;
   }
-  if (!ev.success) {
-    grpc_run_batch_stack_cleanup(&st);
-    rb_raise(grpc_rb_eCallError, "start_batch completion failed");
-    return Qnil;
-  }
 
-  /* Build and return the BatchResult struct result */
+  /* Build and return the BatchResult struct result,
+     if there is an error, it's reflected in the status */
   result = grpc_run_batch_stack_build_result(&st);
   grpc_run_batch_stack_cleanup(&st);
   return result;
 }
 
+static void Init_grpc_write_flags() {
+  /* Constants representing the write flags in grpc.h */
+  VALUE grpc_rb_mWriteFlags =
+      rb_define_module_under(grpc_rb_mGrpcCore, "WriteFlags");
+  rb_define_const(grpc_rb_mWriteFlags, "BUFFER_HINT",
+                  UINT2NUM(GRPC_WRITE_BUFFER_HINT));
+  rb_define_const(grpc_rb_mWriteFlags, "NO_COMPRESS",
+                  UINT2NUM(GRPC_WRITE_NO_COMPRESS));
+}
+
 static void Init_grpc_error_codes() {
   /* Constants representing the error codes of grpc_call_error in grpc.h */
   VALUE grpc_rb_mRpcErrors =
@@ -738,10 +781,14 @@ void Init_grpc_call() {
   rb_define_method(grpc_rb_cCall, "status=", grpc_rb_call_set_status, 1);
   rb_define_method(grpc_rb_cCall, "metadata", grpc_rb_call_get_metadata, 0);
   rb_define_method(grpc_rb_cCall, "metadata=", grpc_rb_call_set_metadata, 1);
+  rb_define_method(grpc_rb_cCall, "write_flag", grpc_rb_call_get_write_flag, 0);
+  rb_define_method(grpc_rb_cCall, "write_flag=", grpc_rb_call_set_write_flag,
+                   1);
 
   /* Ids used to support call attributes */
   id_metadata = rb_intern("metadata");
   id_status = rb_intern("status");
+  id_write_flag = rb_intern("write_flag");
 
   /* Ids used by the c wrapping internals. */
   id_cq = rb_intern("__cq");
@@ -769,6 +816,7 @@ void Init_grpc_call() {
 
   Init_grpc_error_codes();
   Init_grpc_op_codes();
+  Init_grpc_write_flags();
 }
 
 /* Gets the call from the ruby object */
diff --git a/src/ruby/grpc.gemspec b/src/ruby/grpc.gemspec
index eb748458b9..20a6206e7e 100755
--- a/src/ruby/grpc.gemspec
+++ b/src/ruby/grpc.gemspec
@@ -24,16 +24,16 @@ Gem::Specification.new do |s|
   %w(math noproto).each do |b|
     s.executables += ["#{b}_client.rb", "#{b}_server.rb"]
   end
-  s.require_paths = %w( bin lib )
+  s.executables += %w(grpc_ruby_interop_client grpc_ruby_interop_server)
+  s.require_paths = %w( bin lib pb )
   s.platform      = Gem::Platform::RUBY
 
   s.add_dependency 'google-protobuf', '~> 3.0.0alpha.1.1'
-  s.add_dependency 'googleauth', '~> 0.4'  # reqd for interop tests
-  s.add_dependency 'logging', '~> 2.0'
-  s.add_dependency 'minitest', '~> 5.4'  # reqd for interop tests
+  s.add_dependency 'googleauth', '~> 0.4'
 
-  s.add_development_dependency 'simplecov', '~> 0.9'
   s.add_development_dependency 'bundler', '~> 1.9'
+  s.add_development_dependency 'logging', '~> 2.0'
+  s.add_development_dependency 'simplecov', '~> 0.9'
   s.add_development_dependency 'rake', '~> 10.4'
   s.add_development_dependency 'rake-compiler', '~> 0.9'
   s.add_development_dependency 'rspec', '~> 3.2'
diff --git a/src/ruby/lib/grpc/generic/active_call.rb b/src/ruby/lib/grpc/generic/active_call.rb
index 215c0069a3..d9cb924735 100644
--- a/src/ruby/lib/grpc/generic/active_call.rb
+++ b/src/ruby/lib/grpc/generic/active_call.rb
@@ -59,7 +59,7 @@ module GRPC
     include Core::CallOps
     extend Forwardable
     attr_reader(:deadline)
-    def_delegators :@call, :cancel, :metadata
+    def_delegators :@call, :cancel, :metadata, :write_flag, :write_flag=
 
     # client_invoke begins a client invocation.
     #
@@ -74,8 +74,7 @@ module GRPC
     #
     # @param call [Call] a call on which to start and invocation
     # @param q [CompletionQueue] the completion queue
-    # @param deadline [Fixnum,TimeSpec] the deadline
-    def self.client_invoke(call, q, _deadline, **kw)
+    def self.client_invoke(call, q, **kw)
       fail(TypeError, '!Core::Call') unless call.is_a? Core::Call
       unless q.is_a? Core::CompletionQueue
         fail(TypeError, '!Core::CompletionQueue')
@@ -418,7 +417,7 @@ module GRPC
     # @return [Enumerator, nil] a response Enumerator
     def bidi_streamer(requests, **kw, &blk)
       start_call(**kw) unless @started
-      bd = BidiCall.new(@call, @cq, @marshal, @unmarshal, @deadline)
+      bd = BidiCall.new(@call, @cq, @marshal, @unmarshal)
       bd.run_on_client(requests, @op_notifier, &blk)
     end
 
@@ -434,7 +433,7 @@ module GRPC
     #
     # @param gen_each_reply [Proc] generates the BiDi stream replies
     def run_server_bidi(gen_each_reply)
-      bd = BidiCall.new(@call, @cq, @marshal, @unmarshal, @deadline)
+      bd = BidiCall.new(@call, @cq, @marshal, @unmarshal)
       bd.run_on_server(gen_each_reply)
     end
 
@@ -456,7 +455,7 @@ module GRPC
     # Starts the call if not already started
     def start_call(**kw)
       return if @started
-      @metadata_tag = ActiveCall.client_invoke(@call, @cq, @deadline, **kw)
+      @metadata_tag = ActiveCall.client_invoke(@call, @cq, **kw)
       @started = true
     end
 
@@ -485,6 +484,7 @@ module GRPC
     # Operation limits access to an ActiveCall's methods for use as
     # a Operation on the client.
     Operation = view_class(:cancel, :cancelled, :deadline, :execute,
-                           :metadata, :status, :start_call, :wait)
+                           :metadata, :status, :start_call, :wait, :write_flag,
+                           :write_flag=)
   end
 end
diff --git a/src/ruby/lib/grpc/generic/bidi_call.rb b/src/ruby/lib/grpc/generic/bidi_call.rb
index 3b0c71395c..9dbbb74caf 100644
--- a/src/ruby/lib/grpc/generic/bidi_call.rb
+++ b/src/ruby/lib/grpc/generic/bidi_call.rb
@@ -56,15 +56,13 @@ module GRPC
     #          the call
     # @param marshal [Function] f(obj)->string that marshal requests
     # @param unmarshal [Function] f(string)->obj that unmarshals responses
-    # @param deadline [Fixnum] the deadline for the call to complete
-    def initialize(call, q, marshal, unmarshal, deadline)
+    def initialize(call, q, marshal, unmarshal)
       fail(ArgumentError, 'not a call') unless call.is_a? Core::Call
       unless q.is_a? Core::CompletionQueue
         fail(ArgumentError, 'not a CompletionQueue')
       end
       @call = call
       @cq = q
-      @deadline = deadline
       @marshal = marshal
       @op_notifier = nil  # signals completion on clients
       @readq = Queue.new
@@ -99,7 +97,7 @@ module GRPC
     # @param gen_each_reply [Proc] generates the BiDi stream replies.
     def run_on_server(gen_each_reply)
       replys = gen_each_reply.call(each_queued_msg)
-      @loop_th = start_read_loop
+      @loop_th = start_read_loop(is_client: false)
       write_loop(replys, is_client: false)
     end
 
@@ -127,7 +125,7 @@ module GRPC
         count += 1
         req = @readq.pop
         GRPC.logger.debug("each_queued_msg: req = #{req}")
-        throw req if req.is_a? StandardError
+        fail req if req.is_a? StandardError
         break if req.equal?(END_OF_READS)
         yield req
       end
@@ -147,12 +145,9 @@ module GRPC
       GRPC.logger.debug("bidi-write-loop: #{count} writes done")
       if is_client
         GRPC.logger.debug("bidi-write-loop: client sent #{count}, waiting")
-        batch_result = @call.run_batch(@cq, write_tag, INFINITE_FUTURE,
-                                       SEND_CLOSE_FROM_CLIENT => nil,
-                                       RECV_STATUS_ON_CLIENT => nil)
-        @call.status = batch_result.status
-        batch_result.check_status
-        GRPC.logger.debug("bidi-write-loop: done status #{@call.status}")
+        @call.run_batch(@cq, write_tag, INFINITE_FUTURE,
+                        SEND_CLOSE_FROM_CLIENT => nil)
+        GRPC.logger.debug('bidi-write-loop: done')
         notify_done
       end
       GRPC.logger.debug('bidi-write-loop: finished')
@@ -164,7 +159,7 @@ module GRPC
     end
 
     # starts the read loop
-    def start_read_loop
+    def start_read_loop(is_client: true)
       Thread.new do
         GRPC.logger.debug('bidi-read-loop: starting')
         begin
@@ -177,9 +172,19 @@ module GRPC
             # TODO: ensure metadata is read if available, currently it's not
             batch_result = @call.run_batch(@cq, read_tag, INFINITE_FUTURE,
                                            RECV_MESSAGE => nil)
+
             # handle the next message
             if batch_result.message.nil?
               GRPC.logger.debug("bidi-read-loop: null batch #{batch_result}")
+
+              if is_client
+                batch_result = @call.run_batch(@cq, read_tag, INFINITE_FUTURE,
+                                               RECV_STATUS_ON_CLIENT => nil)
+                @call.status = batch_result.status
+                batch_result.check_status
+                GRPC.logger.debug("bidi-read-loop: done status #{@call.status}")
+              end
+
               @readq.push(END_OF_READS)
               GRPC.logger.debug('bidi-read-loop: done reading!')
               break
diff --git a/src/ruby/lib/grpc/generic/client_stub.rb b/src/ruby/lib/grpc/generic/client_stub.rb
index cce718537c..24ec1793f6 100644
--- a/src/ruby/lib/grpc/generic/client_stub.rb
+++ b/src/ruby/lib/grpc/generic/client_stub.rb
@@ -161,15 +161,21 @@ module GRPC
     # @param marshal [Function] f(obj)->string that marshals requests
     # @param unmarshal [Function] f(string)->obj that unmarshals responses
     # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
     # @param parent [Core::Call] a prior call whose reserved metadata
     #   will be propagated by this one.
     # @param return_op [true|false] return an Operation if true
     # @return [Object] the response received from the server
-    def request_response(method, req, marshal, unmarshal, timeout = nil,
+    def request_response(method, req, marshal, unmarshal,
+                         deadline: nil,
+                         timeout: nil,
                          return_op: false,
                          parent: parent,
                          **kw)
-      c = new_active_call(method, marshal, unmarshal, timeout, parent: parent)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent)
       kw_with_jwt_uri = self.class.update_with_jwt_aud_uri(kw, @host, method)
       md = @update_metadata.nil? ? kw : @update_metadata.call(kw_with_jwt_uri)
       return c.request_response(req, **md) unless return_op
@@ -222,16 +228,22 @@ module GRPC
     # @param requests [Object] an Enumerable of requests to send
     # @param marshal [Function] f(obj)->string that marshals requests
     # @param unmarshal [Function] f(string)->obj that unmarshals responses
-    # @param timeout [Numeric] the max completion time in seconds
+    # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
     # @param return_op [true|false] return an Operation if true
     # @param parent [Core::Call] a prior call whose reserved metadata
     #   will be propagated by this one.
     # @return [Object|Operation] the response received from the server
-    def client_streamer(method, requests, marshal, unmarshal, timeout = nil,
+    def client_streamer(method, requests, marshal, unmarshal,
+                        deadline: nil,
+                        timeout: nil,
                         return_op: false,
                         parent: nil,
                         **kw)
-      c = new_active_call(method, marshal, unmarshal, timeout, parent: parent)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent)
       kw_with_jwt_uri = self.class.update_with_jwt_aud_uri(kw, @host, method)
       md = @update_metadata.nil? ? kw : @update_metadata.call(kw_with_jwt_uri)
       return c.client_streamer(requests, **md) unless return_op
@@ -292,18 +304,24 @@ module GRPC
     # @param req [Object] the request sent to the server
     # @param marshal [Function] f(obj)->string that marshals requests
     # @param unmarshal [Function] f(string)->obj that unmarshals responses
-    # @param timeout [Numeric] the max completion time in seconds
+    # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
     # @param return_op [true|false]return an Operation if true
     # @param parent [Core::Call] a prior call whose reserved metadata
     #   will be propagated by this one.
     # @param blk [Block] when provided, is executed for each response
     # @return [Enumerator|Operation|nil] as discussed above
-    def server_streamer(method, req, marshal, unmarshal, timeout = nil,
+    def server_streamer(method, req, marshal, unmarshal,
+                        deadline: nil,
+                        timeout: nil,
                         return_op: false,
                         parent: nil,
                         **kw,
                         &blk)
-      c = new_active_call(method, marshal, unmarshal, timeout, parent: parent)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent)
       kw_with_jwt_uri = self.class.update_with_jwt_aud_uri(kw, @host, method)
       md = @update_metadata.nil? ? kw : @update_metadata.call(kw_with_jwt_uri)
       return c.server_streamer(req, **md, &blk) unless return_op
@@ -404,17 +422,23 @@ module GRPC
     # @param marshal [Function] f(obj)->string that marshals requests
     # @param unmarshal [Function] f(string)->obj that unmarshals responses
     # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
     # @param parent [Core::Call] a prior call whose reserved metadata
     #   will be propagated by this one.
     # @param return_op [true|false] return an Operation if true
     # @param blk [Block] when provided, is executed for each response
     # @return [Enumerator|nil|Operation] as discussed above
-    def bidi_streamer(method, requests, marshal, unmarshal, timeout = nil,
+    def bidi_streamer(method, requests, marshal, unmarshal,
+                      deadline: nil,
+                      timeout: nil,
                       return_op: false,
                       parent: nil,
                       **kw,
                       &blk)
-      c = new_active_call(method, marshal, unmarshal, timeout, parent: parent)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent)
       kw_with_jwt_uri = self.class.update_with_jwt_aud_uri(kw, @host, method)
       md = @update_metadata.nil? ? kw : @update_metadata.call(kw_with_jwt_uri)
       return c.bidi_streamer(requests, **md, &blk) unless return_op
@@ -438,8 +462,13 @@ module GRPC
     # @param parent [Grpc::Call] a parent call, available when calls are
     #   made from server
     # @param timeout [TimeConst]
-    def new_active_call(method, marshal, unmarshal, timeout = nil, parent: nil)
-      deadline = from_relative_time(timeout.nil? ? @timeout : timeout)
+    def new_active_call(method, marshal, unmarshal,
+                        deadline: nil,
+                        timeout: nil,
+                        parent: nil)
+      if deadline.nil?
+        deadline = from_relative_time(timeout.nil? ? @timeout : timeout)
+      end
       call = @ch.create_call(@queue,
                              parent, # parent call
                              @propagate_mask, # propagation options
diff --git a/src/ruby/lib/grpc/generic/service.rb b/src/ruby/lib/grpc/generic/service.rb
index 3b9743ea66..80ff669cca 100644
--- a/src/ruby/lib/grpc/generic/service.rb
+++ b/src/ruby/lib/grpc/generic/service.rb
@@ -174,26 +174,24 @@ module GRPC
             unmarshal = desc.unmarshal_proc(:output)
             route = "/#{route_prefix}/#{name}"
             if desc.request_response?
-              define_method(mth_name) do |req, deadline = nil, **kw|
+              define_method(mth_name) do |req, **kw|
                 GRPC.logger.debug("calling #{@host}:#{route}")
-                request_response(route, req, marshal, unmarshal, deadline, **kw)
+                request_response(route, req, marshal, unmarshal, **kw)
               end
             elsif desc.client_streamer?
-              define_method(mth_name) do |reqs, deadline = nil, **kw|
+              define_method(mth_name) do |reqs, **kw|
                 GRPC.logger.debug("calling #{@host}:#{route}")
-                client_streamer(route, reqs, marshal, unmarshal, deadline, **kw)
+                client_streamer(route, reqs, marshal, unmarshal, **kw)
               end
             elsif desc.server_streamer?
-              define_method(mth_name) do |req, deadline = nil, **kw, &blk|
+              define_method(mth_name) do |req, **kw, &blk|
                 GRPC.logger.debug("calling #{@host}:#{route}")
-                server_streamer(route, req, marshal, unmarshal, deadline, **kw,
-                                &blk)
+                server_streamer(route, req, marshal, unmarshal, **kw, &blk)
               end
             else  # is a bidi_stream
-              define_method(mth_name) do |reqs, deadline = nil, **kw, &blk|
+              define_method(mth_name) do |reqs, **kw, &blk|
                 GRPC.logger.debug("calling #{@host}:#{route}")
-                bidi_streamer(route, reqs, marshal, unmarshal, deadline, **kw,
-                              &blk)
+                bidi_streamer(route, reqs, marshal, unmarshal, **kw, &blk)
               end
             end
           end
diff --git a/src/ruby/lib/grpc/logconfig.rb b/src/ruby/lib/grpc/logconfig.rb
index e9b4aa3c95..6b442febcb 100644
--- a/src/ruby/lib/grpc/logconfig.rb
+++ b/src/ruby/lib/grpc/logconfig.rb
@@ -27,17 +27,33 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-require 'logging'
-
 # GRPC contains the General RPC module.
 module GRPC
-  extend Logging.globally
-end
+  # DefaultLogger is a module included in GRPC if no other logging is set up for
+  # it.  See ../spec/spec_helpers an example of where other logging is added.
+  module DefaultLogger
+    def logger
+      LOGGER
+    end
+
+    private
+
+    # NoopLogger implements the methods of Ruby's conventional logging interface
+    # that are actually used internally within gRPC with a noop implementation.
+    class NoopLogger
+      def info(_ignored)
+      end
 
-Logging.logger.root.appenders = Logging.appenders.stdout
-Logging.logger.root.level = :info
+      def debug(_ignored)
+      end
 
-# TODO: provide command-line configuration for logging
-Logging.logger['GRPC'].level = :info
-Logging.logger['GRPC::ActiveCall'].level = :info
-Logging.logger['GRPC::BidiCall'].level = :info
+      def warn(_ignored)
+      end
+    end
+
+    LOGGER = NoopLogger.new
+  end
+
+  # Inject the noop #logger if no module-level logger method has been injected.
+  extend DefaultLogger unless methods.include?(:logger)
+end
diff --git a/src/ruby/pb/README.md b/src/ruby/pb/README.md
new file mode 100644
index 0000000000..84644e1098
--- /dev/null
+++ b/src/ruby/pb/README.md
@@ -0,0 +1,42 @@
+Protocol Buffers
+================
+
+This folder contains protocol buffers provided with gRPC ruby, and the generated
+code to them.
+
+PREREQUISITES
+-------------
+
+The code is is generated using the protoc (> 3.0.0.alpha.1) and the
+grpc_ruby_plugin.  These must be installed to regenerate the IDL defined
+classes, but that's not necessary just to use them.
+
+health_check/v1alpha
+--------------------
+
+This package defines the surface of a simple health check service that gRPC
+servers may choose to implement, and provides an implementation for it. To
+re-generate the surface.
+
+```bash
+$ # (from this directory)
+$ protoc -I . grpc/health/v1alpha/health.proto \
+    --grpc_out=. \
+    --ruby_out=. \
+    --plugin=protoc-gen-grpc=`which grpc_ruby_plugin`
+```
+
+test
+----
+
+This package defines the surface of the gRPC interop test service and client
+To re-generate the surface, it's necessary to have checked-out versions of
+the grpc interop test proto, e.g, by having the full gRPC repository. E.g,
+
+```bash
+$ # (from this directory within the grpc repo)
+$ protoc -I../../.. ../../../test/proto/{messages,test,empty}.proto \
+    --grpc_out=. \
+    --ruby_out=. \
+    --plugin=protoc-gen-grpc=`which grpc_ruby_plugin`
+```
diff --git a/src/ruby/pb/grpc/health/checker.rb b/src/ruby/pb/grpc/health/checker.rb
new file mode 100644
index 0000000000..8c692e74f9
--- /dev/null
+++ b/src/ruby/pb/grpc/health/checker.rb
@@ -0,0 +1,75 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'grpc'
+require 'grpc/health/v1alpha/health_services'
+require 'thread'
+
+module Grpc
+  # Health contains classes and modules that support providing a health check
+  # service.
+  module Health
+    # Checker is implementation of the schema-specified health checking service.
+    class Checker < V1alpha::Health::Service
+      StatusCodes = GRPC::Core::StatusCodes
+      HealthCheckResponse = V1alpha::HealthCheckResponse
+
+      # Initializes the statuses of participating services
+      def initialize
+        @statuses = {}
+        @status_mutex = Mutex.new  # guards access to @statuses
+      end
+
+      # Implements the rpc IDL API method
+      def check(req, _call)
+        status = nil
+        @status_mutex.synchronize do
+          status = @statuses["#{req.host}/#{req.service}"]
+        end
+        fail GRPC::BadStatus, StatusCodes::NOT_FOUND if status.nil?
+        HealthCheckResponse.new(status: status)
+      end
+
+      # Adds the health status for a given host and service.
+      def add_status(host, service, status)
+        @status_mutex.synchronize { @statuses["#{host}/#{service}"] = status }
+      end
+
+      # Clears the status for the given host or service.
+      def clear_status(host, service)
+        @status_mutex.synchronize { @statuses.delete("#{host}/#{service}") }
+      end
+
+      # Clears alls the statuses.
+      def clear_all
+        @status_mutex.synchronize { @statuses = {} }
+      end
+    end
+  end
+end
diff --git a/src/ruby/pb/grpc/health/v1alpha/health.proto b/src/ruby/pb/grpc/health/v1alpha/health.proto
new file mode 100644
index 0000000000..d31df1e0a7
--- /dev/null
+++ b/src/ruby/pb/grpc/health/v1alpha/health.proto
@@ -0,0 +1,50 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package grpc.health.v1alpha;
+
+message HealthCheckRequest {
+  string host = 1;
+  string service = 2;
+}
+
+message HealthCheckResponse {
+  enum ServingStatus {
+    UNKNOWN = 0;
+    SERVING = 1;
+    NOT_SERVING = 2;
+  }
+  ServingStatus status = 1;
+}
+
+service Health {
+  rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
+}
\ No newline at end of file
diff --git a/src/ruby/pb/grpc/health/v1alpha/health.rb b/src/ruby/pb/grpc/health/v1alpha/health.rb
new file mode 100644
index 0000000000..9c04298ea5
--- /dev/null
+++ b/src/ruby/pb/grpc/health/v1alpha/health.rb
@@ -0,0 +1,29 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: grpc/health/v1alpha/health.proto
+
+require 'google/protobuf'
+
+Google::Protobuf::DescriptorPool.generated_pool.build do
+  add_message "grpc.health.v1alpha.HealthCheckRequest" do
+    optional :host, :string, 1
+    optional :service, :string, 2
+  end
+  add_message "grpc.health.v1alpha.HealthCheckResponse" do
+    optional :status, :enum, 1, "grpc.health.v1alpha.HealthCheckResponse.ServingStatus"
+  end
+  add_enum "grpc.health.v1alpha.HealthCheckResponse.ServingStatus" do
+    value :UNKNOWN, 0
+    value :SERVING, 1
+    value :NOT_SERVING, 2
+  end
+end
+
+module Grpc
+  module Health
+    module V1alpha
+      HealthCheckRequest = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.health.v1alpha.HealthCheckRequest").msgclass
+      HealthCheckResponse = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.health.v1alpha.HealthCheckResponse").msgclass
+      HealthCheckResponse::ServingStatus = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.health.v1alpha.HealthCheckResponse.ServingStatus").enummodule
+    end
+  end
+end
diff --git a/src/ruby/pb/grpc/health/v1alpha/health_services.rb b/src/ruby/pb/grpc/health/v1alpha/health_services.rb
new file mode 100644
index 0000000000..d5cba2e9ec
--- /dev/null
+++ b/src/ruby/pb/grpc/health/v1alpha/health_services.rb
@@ -0,0 +1,28 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# Source: grpc/health/v1alpha/health.proto for package 'grpc.health.v1alpha'
+
+require 'grpc'
+require 'grpc/health/v1alpha/health'
+
+module Grpc
+  module Health
+    module V1alpha
+      module Health
+
+        # TODO: add proto service documentation here
+        class Service
+
+          include GRPC::GenericService
+
+          self.marshal_class_method = :encode
+          self.unmarshal_class_method = :decode
+          self.service_name = 'grpc.health.v1alpha.Health'
+
+          rpc :Check, HealthCheckRequest, HealthCheckResponse
+        end
+
+        Stub = Service.rpc_stub_class
+      end
+    end
+  end
+end
diff --git a/src/ruby/pb/test/client.rb b/src/ruby/pb/test/client.rb
new file mode 100755
index 0000000000..164e304b4d
--- /dev/null
+++ b/src/ruby/pb/test/client.rb
@@ -0,0 +1,453 @@
+#!/usr/bin/env ruby
+
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# client is a testing tool that accesses a gRPC interop testing server and runs
+# a test on it.
+#
+# Helps validate interoperation b/w different gRPC implementations.
+#
+# Usage: $ path/to/client.rb --server_host=<hostname> \
+#                            --server_port=<port> \
+#                            --test_case=<testcase_name>
+
+this_dir = File.expand_path(File.dirname(__FILE__))
+lib_dir = File.join(File.dirname(File.dirname(this_dir)), 'lib')
+pb_dir = File.dirname(File.dirname(this_dir))
+$LOAD_PATH.unshift(lib_dir) unless $LOAD_PATH.include?(lib_dir)
+$LOAD_PATH.unshift(pb_dir) unless $LOAD_PATH.include?(pb_dir)
+$LOAD_PATH.unshift(this_dir) unless $LOAD_PATH.include?(this_dir)
+
+require 'optparse'
+
+require 'grpc'
+require 'googleauth'
+require 'google/protobuf'
+
+require 'test/proto/empty'
+require 'test/proto/messages'
+require 'test/proto/test_services'
+
+require 'signet/ssl_config'
+
+AUTH_ENV = Google::Auth::CredentialsLoader::ENV_VAR
+
+# AssertionError is use to indicate interop test failures.
+class AssertionError < RuntimeError; end
+
+# Fails with AssertionError if the block does evaluate to true
+def assert(msg = 'unknown cause')
+  fail 'No assertion block provided' unless block_given?
+  fail AssertionError, msg unless yield
+end
+
+# loads the certificates used to access the test server securely.
+def load_test_certs
+  this_dir = File.expand_path(File.dirname(__FILE__))
+  data_dir = File.join(File.dirname(File.dirname(this_dir)), 'spec/testdata')
+  files = ['ca.pem', 'server1.key', 'server1.pem']
+  files.map { |f| File.open(File.join(data_dir, f)).read }
+end
+
+# loads the certificates used to access the test server securely.
+def load_prod_cert
+  fail 'could not find a production cert' if ENV['SSL_CERT_FILE'].nil?
+  GRPC.logger.info("loading prod certs from #{ENV['SSL_CERT_FILE']}")
+  File.open(ENV['SSL_CERT_FILE']).read
+end
+
+# creates SSL Credentials from the test certificates.
+def test_creds
+  certs = load_test_certs
+  GRPC::Core::Credentials.new(certs[0])
+end
+
+# creates SSL Credentials from the production certificates.
+def prod_creds
+  cert_text = load_prod_cert
+  GRPC::Core::Credentials.new(cert_text)
+end
+
+# creates the SSL Credentials.
+def ssl_creds(use_test_ca)
+  return test_creds if use_test_ca
+  prod_creds
+end
+
+# creates a test stub that accesses host:port securely.
+def create_stub(opts)
+  address = "#{opts.host}:#{opts.port}"
+  if opts.secure
+    stub_opts = {
+      :creds => ssl_creds(opts.use_test_ca),
+      GRPC::Core::Channel::SSL_TARGET => opts.host_override
+    }
+
+    # Add service account creds if specified
+    wants_creds = %w(all compute_engine_creds service_account_creds)
+    if wants_creds.include?(opts.test_case)
+      unless opts.oauth_scope.nil?
+        auth_creds = Google::Auth.get_application_default(opts.oauth_scope)
+        stub_opts[:update_metadata] = auth_creds.updater_proc
+      end
+    end
+
+    if opts.test_case == 'oauth2_auth_token'
+      auth_creds = Google::Auth.get_application_default(opts.oauth_scope)
+      kw = auth_creds.updater_proc.call({})  # gives as an auth token
+
+      # use a metadata update proc that just adds the auth token.
+      stub_opts[:update_metadata] = proc { |md| md.merge(kw) }
+    end
+
+    if opts.test_case == 'jwt_token_creds'  # don't use a scope
+      auth_creds = Google::Auth.get_application_default
+      stub_opts[:update_metadata] = auth_creds.updater_proc
+    end
+
+    GRPC.logger.info("... connecting securely to #{address}")
+    Grpc::Testing::TestService::Stub.new(address, **stub_opts)
+  else
+    GRPC.logger.info("... connecting insecurely to #{address}")
+    Grpc::Testing::TestService::Stub.new(address)
+  end
+end
+
+# produces a string of null chars (\0) of length l.
+def nulls(l)
+  fail 'requires #{l} to be +ve' if l < 0
+  [].pack('x' * l).force_encoding('utf-8')
+end
+
+# a PingPongPlayer implements the ping pong bidi test.
+class PingPongPlayer
+  include Grpc::Testing
+  include Grpc::Testing::PayloadType
+  attr_accessor :queue
+  attr_accessor :canceller_op
+
+  # reqs is the enumerator over the requests
+  def initialize(msg_sizes)
+    @queue = Queue.new
+    @msg_sizes = msg_sizes
+    @canceller_op = nil  # used to cancel after the first response
+  end
+
+  def each_item
+    return enum_for(:each_item) unless block_given?
+    req_cls, p_cls = StreamingOutputCallRequest, ResponseParameters  # short
+    count = 0
+    @msg_sizes.each do |m|
+      req_size, resp_size = m
+      req = req_cls.new(payload: Payload.new(body: nulls(req_size)),
+                        response_type: :COMPRESSABLE,
+                        response_parameters: [p_cls.new(size: resp_size)])
+      yield req
+      resp = @queue.pop
+      assert('payload type is wrong') { :COMPRESSABLE == resp.payload.type }
+      assert("payload body #{count} has the wrong length") do
+        resp_size == resp.payload.body.length
+      end
+      p "OK: ping_pong #{count}"
+      count += 1
+      unless @canceller_op.nil?
+        canceller_op.cancel
+        break
+      end
+    end
+  end
+end
+
+# defines methods corresponding to each interop test case.
+class NamedTests
+  include Grpc::Testing
+  include Grpc::Testing::PayloadType
+
+  def initialize(stub, args)
+    @stub = stub
+    @args = args
+  end
+
+  def empty_unary
+    resp = @stub.empty_call(Empty.new)
+    assert('empty_unary: invalid response') { resp.is_a?(Empty) }
+    p 'OK: empty_unary'
+  end
+
+  def large_unary
+    perform_large_unary
+    p 'OK: large_unary'
+  end
+
+  def service_account_creds
+    # ignore this test if the oauth options are not set
+    if @args.oauth_scope.nil?
+      p 'NOT RUN: service_account_creds; no service_account settings'
+      return
+    end
+    json_key = File.read(ENV[AUTH_ENV])
+    wanted_email = MultiJson.load(json_key)['client_email']
+    resp = perform_large_unary(fill_username: true,
+                               fill_oauth_scope: true)
+    assert("#{__callee__}: bad username") { wanted_email == resp.username }
+    assert("#{__callee__}: bad oauth scope") do
+      @args.oauth_scope.include?(resp.oauth_scope)
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def jwt_token_creds
+    json_key = File.read(ENV[AUTH_ENV])
+    wanted_email = MultiJson.load(json_key)['client_email']
+    resp = perform_large_unary(fill_username: true)
+    assert("#{__callee__}: bad username") { wanted_email == resp.username }
+    p "OK: #{__callee__}"
+  end
+
+  def compute_engine_creds
+    resp = perform_large_unary(fill_username: true,
+                               fill_oauth_scope: true)
+    assert("#{__callee__}: bad username") do
+      @args.default_service_account == resp.username
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def oauth2_auth_token
+    resp = perform_large_unary(fill_username: true,
+                               fill_oauth_scope: true)
+    json_key = File.read(ENV[AUTH_ENV])
+    wanted_email = MultiJson.load(json_key)['client_email']
+    assert("#{__callee__}: bad username") { wanted_email == resp.username }
+    assert("#{__callee__}: bad oauth scope") do
+      @args.oauth_scope.include?(resp.oauth_scope)
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def per_rpc_creds
+    auth_creds = Google::Auth.get_application_default(@args.oauth_scope)
+    kw = auth_creds.updater_proc.call({})
+    resp = perform_large_unary(fill_username: true,
+                               fill_oauth_scope: true,
+                               **kw)
+    json_key = File.read(ENV[AUTH_ENV])
+    wanted_email = MultiJson.load(json_key)['client_email']
+    assert("#{__callee__}: bad username") { wanted_email == resp.username }
+    assert("#{__callee__}: bad oauth scope") do
+      @args.oauth_scope.include?(resp.oauth_scope)
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def client_streaming
+    msg_sizes = [27_182, 8, 1828, 45_904]
+    wanted_aggregate_size = 74_922
+    reqs = msg_sizes.map do |x|
+      req = Payload.new(body: nulls(x))
+      StreamingInputCallRequest.new(payload: req)
+    end
+    resp = @stub.streaming_input_call(reqs)
+    assert("#{__callee__}: aggregate payload size is incorrect") do
+      wanted_aggregate_size == resp.aggregated_payload_size
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def server_streaming
+    msg_sizes = [31_415, 9, 2653, 58_979]
+    response_spec = msg_sizes.map { |s| ResponseParameters.new(size: s) }
+    req = StreamingOutputCallRequest.new(response_type: :COMPRESSABLE,
+                                         response_parameters: response_spec)
+    resps = @stub.streaming_output_call(req)
+    resps.each_with_index do |r, i|
+      assert("#{__callee__}: too many responses") { i < msg_sizes.length }
+      assert("#{__callee__}: payload body #{i} has the wrong length") do
+        msg_sizes[i] == r.payload.body.length
+      end
+      assert("#{__callee__}: payload type is wrong") do
+        :COMPRESSABLE == r.payload.type
+      end
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def ping_pong
+    msg_sizes = [[27_182, 31_415], [8, 9], [1828, 2653], [45_904, 58_979]]
+    ppp = PingPongPlayer.new(msg_sizes)
+    resps = @stub.full_duplex_call(ppp.each_item)
+    resps.each { |r| ppp.queue.push(r) }
+    p "OK: #{__callee__}"
+  end
+
+  def timeout_on_sleeping_server
+    msg_sizes = [[27_182, 31_415]]
+    ppp = PingPongPlayer.new(msg_sizes)
+    resps = @stub.full_duplex_call(ppp.each_item, timeout: 0.001)
+    resps.each { |r| ppp.queue.push(r) }
+    fail 'Should have raised GRPC::BadStatus(DEADLINE_EXCEEDED)'
+  rescue GRPC::BadStatus => e
+    assert("#{__callee__}: status was wrong") do
+      e.code == GRPC::Core::StatusCodes::DEADLINE_EXCEEDED
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def empty_stream
+    ppp = PingPongPlayer.new([])
+    resps = @stub.full_duplex_call(ppp.each_item)
+    count = 0
+    resps.each do |r|
+      ppp.queue.push(r)
+      count += 1
+    end
+    assert("#{__callee__}: too many responses expected 0") do
+      count == 0
+    end
+    p "OK: #{__callee__}"
+  end
+
+  def cancel_after_begin
+    msg_sizes = [27_182, 8, 1828, 45_904]
+    reqs = msg_sizes.map do |x|
+      req = Payload.new(body: nulls(x))
+      StreamingInputCallRequest.new(payload: req)
+    end
+    op = @stub.streaming_input_call(reqs, return_op: true)
+    op.cancel
+    op.execute
+    fail 'Should have raised GRPC:Cancelled'
+  rescue GRPC::Cancelled
+    assert("#{__callee__}: call operation should be CANCELLED") { op.cancelled }
+    p "OK: #{__callee__}"
+  end
+
+  def cancel_after_first_response
+    msg_sizes = [[27_182, 31_415], [8, 9], [1828, 2653], [45_904, 58_979]]
+    ppp = PingPongPlayer.new(msg_sizes)
+    op = @stub.full_duplex_call(ppp.each_item, return_op: true)
+    ppp.canceller_op = op  # causes ppp to cancel after the 1st message
+    op.execute.each { |r| ppp.queue.push(r) }
+    fail 'Should have raised GRPC:Cancelled'
+  rescue GRPC::Cancelled
+    assert("#{__callee__}: call operation should be CANCELLED") { op.cancelled }
+    op.wait
+    p "OK: #{__callee__}"
+  end
+
+  def all
+    all_methods = NamedTests.instance_methods(false).map(&:to_s)
+    all_methods.each do |m|
+      next if m == 'all' || m.start_with?('assert')
+      p "TESTCASE: #{m}"
+      method(m).call
+    end
+  end
+
+  private
+
+  def perform_large_unary(fill_username: false, fill_oauth_scope: false, **kw)
+    req_size, wanted_response_size = 271_828, 314_159
+    payload = Payload.new(type: :COMPRESSABLE, body: nulls(req_size))
+    req = SimpleRequest.new(response_type: :COMPRESSABLE,
+                            response_size: wanted_response_size,
+                            payload: payload)
+    req.fill_username = fill_username
+    req.fill_oauth_scope = fill_oauth_scope
+    resp = @stub.unary_call(req, **kw)
+    assert('payload type is wrong') do
+      :COMPRESSABLE == resp.payload.type
+    end
+    assert('payload body has the wrong length') do
+      wanted_response_size == resp.payload.body.length
+    end
+    assert('payload body is invalid') do
+      nulls(wanted_response_size) == resp.payload.body
+    end
+    resp
+  end
+end
+
+# Args is used to hold the command line info.
+Args = Struct.new(:default_service_account, :host, :host_override,
+                  :oauth_scope, :port, :secure, :test_case,
+                  :use_test_ca)
+
+# validates the the command line options, returning them as a Hash.
+def parse_args
+  args = Args.new
+  args.host_override = 'foo.test.google.fr'
+  OptionParser.new do |opts|
+    opts.on('--oauth_scope scope',
+            'Scope for OAuth tokens') { |v| args['oauth_scope'] = v }
+    opts.on('--server_host SERVER_HOST', 'server hostname') do |v|
+      args['host'] = v
+    end
+    opts.on('--default_service_account email_address',
+            'email address of the default service account') do |v|
+      args['default_service_account'] = v
+    end
+    opts.on('--server_host_override HOST_OVERRIDE',
+            'override host via a HTTP header') do |v|
+      args['host_override'] = v
+    end
+    opts.on('--server_port SERVER_PORT', 'server port') { |v| args['port'] = v }
+    # instance_methods(false) gives only the methods defined in that class
+    test_cases = NamedTests.instance_methods(false).map(&:to_s)
+    test_case_list = test_cases.join(',')
+    opts.on('--test_case CODE', test_cases, {}, 'select a test_case',
+            "  (#{test_case_list})") { |v| args['test_case'] = v }
+    opts.on('-s', '--use_tls', 'require a secure connection?') do |v|
+      args['secure'] = v
+    end
+    opts.on('-t', '--use_test_ca',
+            'if secure, use the test certificate?') do |v|
+      args['use_test_ca'] = v
+    end
+  end.parse!
+  _check_args(args)
+end
+
+def _check_args(args)
+  %w(host port test_case).each do |a|
+    if args[a].nil?
+      fail(OptionParser::MissingArgument, "please specify --#{a}")
+    end
+  end
+  args
+end
+
+def main
+  opts = parse_args
+  stub = create_stub(opts)
+  NamedTests.new(stub, opts).method(opts['test_case']).call
+end
+
+main
diff --git a/src/ruby/pb/test/proto/empty.rb b/src/ruby/pb/test/proto/empty.rb
new file mode 100644
index 0000000000..559adcc85e
--- /dev/null
+++ b/src/ruby/pb/test/proto/empty.rb
@@ -0,0 +1,15 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: test/proto/empty.proto
+
+require 'google/protobuf'
+
+Google::Protobuf::DescriptorPool.generated_pool.build do
+  add_message "grpc.testing.Empty" do
+  end
+end
+
+module Grpc
+  module Testing
+    Empty = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.Empty").msgclass
+  end
+end
diff --git a/src/ruby/bin/interop/test/cpp/interop/messages.rb b/src/ruby/pb/test/proto/messages.rb
index 89c349b406..9b7f977285 100644
--- a/src/ruby/bin/interop/test/cpp/interop/messages.rb
+++ b/src/ruby/pb/test/proto/messages.rb
@@ -1,34 +1,5 @@
-# Copyright 2015, Google Inc.
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-# notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-# copyright notice, this list of conditions and the following disclaimer
-# in the documentation and/or other materials provided with the
-# distribution.
-#     * Neither the name of Google Inc. nor the names of its
-# contributors may be used to endorse or promote products derived from
-# this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
-# source: test/cpp/interop/messages.proto
+# source: test/proto/messages.proto
 
 require 'google/protobuf'
 
@@ -37,12 +8,18 @@ Google::Protobuf::DescriptorPool.generated_pool.build do
     optional :type, :enum, 1, "grpc.testing.PayloadType"
     optional :body, :string, 2
   end
+  add_message "grpc.testing.EchoStatus" do
+    optional :code, :int32, 1
+    optional :message, :string, 2
+  end
   add_message "grpc.testing.SimpleRequest" do
     optional :response_type, :enum, 1, "grpc.testing.PayloadType"
     optional :response_size, :int32, 2
     optional :payload, :message, 3, "grpc.testing.Payload"
     optional :fill_username, :bool, 4
     optional :fill_oauth_scope, :bool, 5
+    optional :response_compression, :enum, 6, "grpc.testing.CompressionType"
+    optional :response_status, :message, 7, "grpc.testing.EchoStatus"
   end
   add_message "grpc.testing.SimpleResponse" do
     optional :payload, :message, 1, "grpc.testing.Payload"
@@ -63,20 +40,32 @@ Google::Protobuf::DescriptorPool.generated_pool.build do
     optional :response_type, :enum, 1, "grpc.testing.PayloadType"
     repeated :response_parameters, :message, 2, "grpc.testing.ResponseParameters"
     optional :payload, :message, 3, "grpc.testing.Payload"
+    optional :response_compression, :enum, 6, "grpc.testing.CompressionType"
+    optional :response_status, :message, 7, "grpc.testing.EchoStatus"
   end
   add_message "grpc.testing.StreamingOutputCallResponse" do
     optional :payload, :message, 1, "grpc.testing.Payload"
   end
+  add_message "grpc.testing.ReconnectInfo" do
+    optional :passed, :bool, 1
+    repeated :backoff_ms, :int32, 2
+  end
   add_enum "grpc.testing.PayloadType" do
     value :COMPRESSABLE, 0
     value :UNCOMPRESSABLE, 1
     value :RANDOM, 2
   end
+  add_enum "grpc.testing.CompressionType" do
+    value :NONE, 0
+    value :GZIP, 1
+    value :DEFLATE, 2
+  end
 end
 
 module Grpc
   module Testing
     Payload = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.Payload").msgclass
+    EchoStatus = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.EchoStatus").msgclass
     SimpleRequest = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.SimpleRequest").msgclass
     SimpleResponse = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.SimpleResponse").msgclass
     StreamingInputCallRequest = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.StreamingInputCallRequest").msgclass
@@ -84,6 +73,8 @@ module Grpc
     ResponseParameters = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.ResponseParameters").msgclass
     StreamingOutputCallRequest = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.StreamingOutputCallRequest").msgclass
     StreamingOutputCallResponse = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.StreamingOutputCallResponse").msgclass
+    ReconnectInfo = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.ReconnectInfo").msgclass
     PayloadType = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.PayloadType").enummodule
+    CompressionType = Google::Protobuf::DescriptorPool.generated_pool.lookup("grpc.testing.CompressionType").enummodule
   end
 end
diff --git a/src/ruby/pb/test/proto/test.rb b/src/ruby/pb/test/proto/test.rb
new file mode 100644
index 0000000000..100eb6505c
--- /dev/null
+++ b/src/ruby/pb/test/proto/test.rb
@@ -0,0 +1,14 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: test/proto/test.proto
+
+require 'google/protobuf'
+
+require 'test/proto/empty'
+require 'test/proto/messages'
+Google::Protobuf::DescriptorPool.generated_pool.build do
+end
+
+module Grpc
+  module Testing
+  end
+end
diff --git a/src/ruby/pb/test/proto/test_services.rb b/src/ruby/pb/test/proto/test_services.rb
new file mode 100644
index 0000000000..9df9cc5860
--- /dev/null
+++ b/src/ruby/pb/test/proto/test_services.rb
@@ -0,0 +1,64 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# Source: test/proto/test.proto for package 'grpc.testing'
+
+require 'grpc'
+require 'test/proto/test'
+
+module Grpc
+  module Testing
+    module TestService
+
+      # TODO: add proto service documentation here
+      class Service
+
+        include GRPC::GenericService
+
+        self.marshal_class_method = :encode
+        self.unmarshal_class_method = :decode
+        self.service_name = 'grpc.testing.TestService'
+
+        rpc :EmptyCall, Empty, Empty
+        rpc :UnaryCall, SimpleRequest, SimpleResponse
+        rpc :StreamingOutputCall, StreamingOutputCallRequest, stream(StreamingOutputCallResponse)
+        rpc :StreamingInputCall, stream(StreamingInputCallRequest), StreamingInputCallResponse
+        rpc :FullDuplexCall, stream(StreamingOutputCallRequest), stream(StreamingOutputCallResponse)
+        rpc :HalfDuplexCall, stream(StreamingOutputCallRequest), stream(StreamingOutputCallResponse)
+      end
+
+      Stub = Service.rpc_stub_class
+    end
+    module UnimplementedService
+
+      # TODO: add proto service documentation here
+      class Service
+
+        include GRPC::GenericService
+
+        self.marshal_class_method = :encode
+        self.unmarshal_class_method = :decode
+        self.service_name = 'grpc.testing.UnimplementedService'
+
+        rpc :UnimplementedCall, Empty, Empty
+      end
+
+      Stub = Service.rpc_stub_class
+    end
+    module ReconnectService
+
+      # TODO: add proto service documentation here
+      class Service
+
+        include GRPC::GenericService
+
+        self.marshal_class_method = :encode
+        self.unmarshal_class_method = :decode
+        self.service_name = 'grpc.testing.ReconnectService'
+
+        rpc :Start, Empty, Empty
+        rpc :Stop, Empty, ReconnectInfo
+      end
+
+      Stub = Service.rpc_stub_class
+    end
+  end
+end
diff --git a/src/ruby/pb/test/server.rb b/src/ruby/pb/test/server.rb
new file mode 100755
index 0000000000..e2e1ecbd62
--- /dev/null
+++ b/src/ruby/pb/test/server.rb
@@ -0,0 +1,196 @@
+#!/usr/bin/env ruby
+
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# interop_server is a Testing app that runs a gRPC interop testing server.
+#
+# It helps validate interoperation b/w gRPC in different environments
+#
+# Helps validate interoperation b/w different gRPC implementations.
+#
+# Usage: $ path/to/interop_server.rb --port
+
+this_dir = File.expand_path(File.dirname(__FILE__))
+lib_dir = File.join(File.dirname(File.dirname(this_dir)), 'lib')
+pb_dir = File.dirname(File.dirname(this_dir))
+$LOAD_PATH.unshift(lib_dir) unless $LOAD_PATH.include?(lib_dir)
+$LOAD_PATH.unshift(pb_dir) unless $LOAD_PATH.include?(pb_dir)
+$LOAD_PATH.unshift(this_dir) unless $LOAD_PATH.include?(this_dir)
+
+require 'forwardable'
+require 'optparse'
+
+require 'grpc'
+
+require 'test/proto/empty'
+require 'test/proto/messages'
+require 'test/proto/test_services'
+
+# loads the certificates by the test server.
+def load_test_certs
+  this_dir = File.expand_path(File.dirname(__FILE__))
+  data_dir = File.join(File.dirname(File.dirname(this_dir)), 'spec/testdata')
+  files = ['ca.pem', 'server1.key', 'server1.pem']
+  files.map { |f| File.open(File.join(data_dir, f)).read }
+end
+
+# creates a ServerCredentials from the test certificates.
+def test_server_creds
+  certs = load_test_certs
+  GRPC::Core::ServerCredentials.new(nil, certs[1], certs[2])
+end
+
+# produces a string of null chars (\0) of length l.
+def nulls(l)
+  fail 'requires #{l} to be +ve' if l < 0
+  [].pack('x' * l).force_encoding('utf-8')
+end
+
+# A EnumeratorQueue wraps a Queue yielding the items added to it via each_item.
+class EnumeratorQueue
+  extend Forwardable
+  def_delegators :@q, :push
+
+  def initialize(sentinel)
+    @q = Queue.new
+    @sentinel = sentinel
+  end
+
+  def each_item
+    return enum_for(:each_item) unless block_given?
+    loop do
+      r = @q.pop
+      break if r.equal?(@sentinel)
+      fail r if r.is_a? Exception
+      yield r
+    end
+  end
+end
+
+# A runnable implementation of the schema-specified testing service, with each
+# service method implemented as required by the interop testing spec.
+class TestTarget < Grpc::Testing::TestService::Service
+  include Grpc::Testing
+  include Grpc::Testing::PayloadType
+
+  def empty_call(_empty, _call)
+    Empty.new
+  end
+
+  def unary_call(simple_req, _call)
+    req_size = simple_req.response_size
+    SimpleResponse.new(payload: Payload.new(type: :COMPRESSABLE,
+                                            body: nulls(req_size)))
+  end
+
+  def streaming_input_call(call)
+    sizes = call.each_remote_read.map { |x| x.payload.body.length }
+    sum = sizes.inject { |s, x| s + x }
+    StreamingInputCallResponse.new(aggregated_payload_size: sum)
+  end
+
+  def streaming_output_call(req, _call)
+    cls = StreamingOutputCallResponse
+    req.response_parameters.map do |p|
+      cls.new(payload: Payload.new(type: req.response_type,
+                                   body: nulls(p.size)))
+    end
+  end
+
+  def full_duplex_call(reqs)
+    # reqs is a lazy Enumerator of the requests sent by the client.
+    q = EnumeratorQueue.new(self)
+    cls = StreamingOutputCallResponse
+    Thread.new do
+      begin
+        GRPC.logger.info('interop-server: started receiving')
+        reqs.each do |req|
+          resp_size = req.response_parameters[0].size
+          GRPC.logger.info("read a req, response size is #{resp_size}")
+          resp = cls.new(payload: Payload.new(type: req.response_type,
+                                              body: nulls(resp_size)))
+          q.push(resp)
+        end
+        GRPC.logger.info('interop-server: finished receiving')
+        q.push(self)
+      rescue StandardError => e
+        GRPC.logger.info('interop-server: failed')
+        GRPC.logger.warn(e)
+        q.push(e)  # share the exception with the enumerator
+      end
+    end
+    q.each_item
+  end
+
+  def half_duplex_call(reqs)
+    # TODO: update with unique behaviour of the half_duplex_call if that's
+    # ever required by any of the tests.
+    full_duplex_call(reqs)
+  end
+end
+
+# validates the the command line options, returning them as a Hash.
+def parse_options
+  options = {
+    'port' => nil,
+    'secure' => false
+  }
+  OptionParser.new do |opts|
+    opts.banner = 'Usage: --port port'
+    opts.on('--port PORT', 'server port') do |v|
+      options['port'] = v
+    end
+    opts.on('-s', '--use_tls', 'require a secure connection?') do |v|
+      options['secure'] = v
+    end
+  end.parse!
+
+  if options['port'].nil?
+    fail(OptionParser::MissingArgument, 'please specify --port')
+  end
+  options
+end
+
+def main
+  opts = parse_options
+  host = "0.0.0.0:#{opts['port']}"
+  s = GRPC::RpcServer.new
+  if opts['secure']
+    s.add_http2_port(host, test_server_creds)
+    GRPC.logger.info("... running securely on #{host}")
+  else
+    s.add_http2_port(host)
+    GRPC.logger.info("... running insecurely on #{host}")
+  end
+  s.handle(TestTarget)
+  s.run_till_terminated
+end
+
+main
diff --git a/src/ruby/spec/call_spec.rb b/src/ruby/spec/call_spec.rb
index 3c5d33ffcd..dd3c45f754 100644
--- a/src/ruby/spec/call_spec.rb
+++ b/src/ruby/spec/call_spec.rb
@@ -31,6 +31,14 @@ require 'grpc'
 
 include GRPC::Core::StatusCodes
 
+describe GRPC::Core::WriteFlags do
+  it 'should define the known write flag values' do
+    m = GRPC::Core::WriteFlags
+    expect(m.const_get(:BUFFER_HINT)).to_not be_nil
+    expect(m.const_get(:NO_COMPRESS)).to_not be_nil
+  end
+end
+
 describe GRPC::Core::RpcErrors do
   before(:each) do
     @known_types = {
diff --git a/src/ruby/spec/generic/active_call_spec.rb b/src/ruby/spec/generic/active_call_spec.rb
index 0bf65ba2e9..fcd7bd082f 100644
--- a/src/ruby/spec/generic/active_call_spec.rb
+++ b/src/ruby/spec/generic/active_call_spec.rb
@@ -35,6 +35,7 @@ describe GRPC::ActiveCall do
   ActiveCall = GRPC::ActiveCall
   Call = GRPC::Core::Call
   CallOps = GRPC::Core::CallOps
+  WriteFlags = GRPC::Core::WriteFlags
 
   before(:each) do
     @pass_through = proc { |x| x }
@@ -57,7 +58,7 @@ describe GRPC::ActiveCall do
   describe 'restricted view methods' do
     before(:each) do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       @client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                     @pass_through, deadline,
                                     metadata_tag: md_tag)
@@ -87,7 +88,7 @@ describe GRPC::ActiveCall do
   describe '#remote_send' do
     it 'allows a client to send a payload to the server' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       @client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                     @pass_through, deadline,
                                     metadata_tag: md_tag)
@@ -111,7 +112,7 @@ describe GRPC::ActiveCall do
 
     it 'marshals the payload using the marshal func' do
       call = make_test_call
-      ActiveCall.client_invoke(call, @client_queue, deadline)
+      ActiveCall.client_invoke(call, @client_queue)
       marshal = proc { |x| 'marshalled:' + x }
       client_call = ActiveCall.new(call, @client_queue, marshal,
                                    @pass_through, deadline)
@@ -129,13 +130,37 @@ describe GRPC::ActiveCall do
                                    @pass_through, deadline)
       expect(server_call.remote_read).to eq('marshalled:' + msg)
     end
+
+    TEST_WRITE_FLAGS = [WriteFlags::BUFFER_HINT, WriteFlags::NO_COMPRESS]
+    TEST_WRITE_FLAGS.each do |f|
+      it "successfully makes calls with write_flag set to #{f}" do
+        call = make_test_call
+        ActiveCall.client_invoke(call, @client_queue)
+        marshal = proc { |x| 'marshalled:' + x }
+        client_call = ActiveCall.new(call, @client_queue, marshal,
+                                     @pass_through, deadline)
+        msg = 'message is a string'
+        client_call.write_flag = f
+        client_call.remote_send(msg)
+
+        # confirm that the message was marshalled
+        recvd_rpc =  @server.request_call(@server_queue, @server_tag, deadline)
+        recvd_call = recvd_rpc.call
+        server_ops = {
+          CallOps::SEND_INITIAL_METADATA => nil
+        }
+        recvd_call.run_batch(@server_queue, @server_tag, deadline, server_ops)
+        server_call = ActiveCall.new(recvd_call, @server_queue, @pass_through,
+                                     @pass_through, deadline)
+        expect(server_call.remote_read).to eq('marshalled:' + msg)
+      end
+    end
   end
 
   describe '#client_invoke' do
     it 'sends keywords as metadata to the server when the are present' do
       call = make_test_call
-      ActiveCall.client_invoke(call, @client_queue, deadline,
-                               k1: 'v1', k2: 'v2')
+      ActiveCall.client_invoke(call, @client_queue, k1: 'v1', k2: 'v2')
       recvd_rpc =  @server.request_call(@server_queue, @server_tag, deadline)
       recvd_call = recvd_rpc.call
       expect(recvd_call).to_not be_nil
@@ -148,7 +173,7 @@ describe GRPC::ActiveCall do
   describe '#remote_read' do
     it 'reads the response sent by a server' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -161,7 +186,7 @@ describe GRPC::ActiveCall do
 
     it 'saves no metadata when the server adds no metadata' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -176,7 +201,7 @@ describe GRPC::ActiveCall do
 
     it 'saves metadata add by the server' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -192,7 +217,7 @@ describe GRPC::ActiveCall do
 
     it 'get a nil msg before a status when an OK status is sent' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -209,7 +234,7 @@ describe GRPC::ActiveCall do
 
     it 'unmarshals the response using the unmarshal func' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       unmarshal = proc { |x| 'unmarshalled:' + x }
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    unmarshal, deadline,
@@ -234,7 +259,7 @@ describe GRPC::ActiveCall do
 
     it 'the returns an enumerator that can read n responses' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -252,7 +277,7 @@ describe GRPC::ActiveCall do
 
     it 'the returns an enumerator that stops after an OK Status' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -262,7 +287,7 @@ describe GRPC::ActiveCall do
       client_call.writes_done(false)
       server_call = expect_server_to_receive(msg)
       e = client_call.each_remote_read
-      n = 3  # arbitrary value > 1
+      n = 3 # arbitrary value > 1
       n.times do
         server_call.remote_send(reply)
         expect(e.next).to eq(reply)
@@ -275,7 +300,7 @@ describe GRPC::ActiveCall do
   describe '#writes_done' do
     it 'finishes ok if the server sends a status response' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -291,7 +316,7 @@ describe GRPC::ActiveCall do
 
     it 'finishes ok if the server sends an early status response' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
@@ -307,7 +332,7 @@ describe GRPC::ActiveCall do
 
     it 'finishes ok if writes_done is true' do
       call = make_test_call
-      md_tag = ActiveCall.client_invoke(call, @client_queue, deadline)
+      md_tag = ActiveCall.client_invoke(call, @client_queue)
       client_call = ActiveCall.new(call, @client_queue, @pass_through,
                                    @pass_through, deadline,
                                    metadata_tag: md_tag)
diff --git a/src/ruby/spec/generic/client_stub_spec.rb b/src/ruby/spec/generic/client_stub_spec.rb
index 68d4b11790..edcc962a7d 100644
--- a/src/ruby/spec/generic/client_stub_spec.rb
+++ b/src/ruby/spec/generic/client_stub_spec.rb
@@ -408,6 +408,26 @@ describe 'ClientStub' do
 
       it_behaves_like 'bidi streaming'
     end
+
+    describe 'without enough time to run' do
+      before(:each) do
+        @sent_msgs = Array.new(3) { |i| 'msg_' + (i + 1).to_s }
+        @replys = Array.new(3) { |i| 'reply_' + (i + 1).to_s }
+        server_port = create_test_server
+        @host = "localhost:#{server_port}"
+      end
+
+      it 'should fail with DeadlineExceeded', bidi: true do
+        @server.start
+        stub = GRPC::ClientStub.new(@host, @cq)
+        blk = proc do
+          e = stub.bidi_streamer(@method, @sent_msgs, noop, noop,
+                                 timeout: 0.001)
+          e.collect { |r| r }
+        end
+        expect(&blk).to raise_error GRPC::BadStatus, /Deadline Exceeded/
+      end
+    end
   end
 
   def run_server_streamer(expected_input, replys, status, **kw)
diff --git a/src/ruby/spec/generic/rpc_server_spec.rb b/src/ruby/spec/generic/rpc_server_spec.rb
index 0326f6e894..1295fd7fdd 100644
--- a/src/ruby/spec/generic/rpc_server_spec.rb
+++ b/src/ruby/spec/generic/rpc_server_spec.rb
@@ -396,8 +396,9 @@ describe GRPC::RpcServer do
         @srv.wait_till_running
         req = EchoMsg.new
         stub = SlowStub.new(@host, **client_opts)
-        deadline = service.delay + 1.0 # wait for long enough
-        expect(stub.an_rpc(req, deadline, k1: 'v1', k2: 'v2')).to be_a(EchoMsg)
+        timeout = service.delay + 1.0 # wait for long enough
+        resp = stub.an_rpc(req, timeout: timeout, k1: 'v1', k2: 'v2')
+        expect(resp).to be_a(EchoMsg)
         wanted_md = [{ 'k1' => 'v1', 'k2' => 'v2' }]
         check_md(wanted_md, service.received_md)
         @srv.stop
@@ -411,8 +412,8 @@ describe GRPC::RpcServer do
         @srv.wait_till_running
         req = EchoMsg.new
         stub = SlowStub.new(@host, **client_opts)
-        deadline = 0.1  # too short for SlowService to respond
-        blk = proc { stub.an_rpc(req, deadline, k1: 'v1', k2: 'v2') }
+        timeout = 0.1  # too short for SlowService to respond
+        blk = proc { stub.an_rpc(req, timeout: timeout, k1: 'v1', k2: 'v2') }
         expect(&blk).to raise_error GRPC::BadStatus
         wanted_md = []
         expect(service.received_md).to eq(wanted_md)
diff --git a/src/ruby/spec/pb/health/checker_spec.rb b/src/ruby/spec/pb/health/checker_spec.rb
new file mode 100644
index 0000000000..6999a69105
--- /dev/null
+++ b/src/ruby/spec/pb/health/checker_spec.rb
@@ -0,0 +1,233 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'grpc'
+require 'grpc/health/v1alpha/health'
+require 'grpc/health/checker'
+require 'open3'
+
+def can_run_codegen_check
+  system('which grpc_ruby_plugin') && system('which protoc')
+end
+
+describe 'Health protobuf code generation' do
+  context 'the health service file used by grpc/health/checker' do
+    if !can_run_codegen_check
+      skip 'protoc || grpc_ruby_plugin missing, cannot verify health code-gen'
+    else
+      it 'should already be loaded indirectly i.e, used by the other specs' do
+        expect(require('grpc/health/v1alpha/health_services')).to be(false)
+      end
+
+      it 'should have the same content as created by code generation' do
+        root_dir = File.dirname(
+          File.dirname(File.dirname(File.dirname(__FILE__))))
+        pb_dir = File.join(root_dir, 'pb')
+
+        # Get the current content
+        service_path = File.join(pb_dir, 'grpc', 'health', 'v1alpha',
+                                 'health_services.rb')
+        want = nil
+        File.open(service_path) { |f| want = f.read }
+
+        # Regenerate it
+        plugin, = Open3.capture2('which', 'grpc_ruby_plugin')
+        plugin = plugin.strip
+        got = nil
+        Dir.mktmpdir do |tmp_dir|
+          gen_out = File.join(tmp_dir, 'grpc', 'health', 'v1alpha',
+                              'health_services.rb')
+          pid = spawn(
+            'protoc',
+            '-I.',
+            'grpc/health/v1alpha/health.proto',
+            "--grpc_out=#{tmp_dir}",
+            "--plugin=protoc-gen-grpc=#{plugin}",
+            chdir: pb_dir)
+          Process.wait(pid)
+          File.open(gen_out) { |f| got = f.read }
+        end
+        expect(got).to eq(want)
+      end
+    end
+  end
+end
+
+describe Grpc::Health::Checker do
+  StatusCodes = GRPC::Core::StatusCodes
+  ServingStatus = Grpc::Health::V1alpha::HealthCheckResponse::ServingStatus
+  HCResp = Grpc::Health::V1alpha::HealthCheckResponse
+  HCReq = Grpc::Health::V1alpha::HealthCheckRequest
+  success_tests =
+    [
+      {
+        desc: 'neither host or service are specified',
+        host: '',
+        service: ''
+      }, {
+        desc: 'only the host is specified',
+        host: 'test-fake-host',
+        service: ''
+      }, {
+        desc: 'the host and service are specified',
+        host: 'test-fake-host',
+        service: 'fake-service-1'
+      }, {
+        desc: 'only the service is specified',
+        host: '',
+        service: 'fake-service-2'
+      }
+    ]
+
+  context 'initialization' do
+    it 'can be constructed with no args' do
+      expect(subject).to_not be(nil)
+    end
+  end
+
+  context 'method `add_status` and `check`' do
+    success_tests.each do |t|
+      it "should succeed when #{t[:desc]}" do
+        subject.add_status(t[:host], t[:service], ServingStatus::NOT_SERVING)
+        got = subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                            nil)
+        want = HCResp.new(status: ServingStatus::NOT_SERVING)
+        expect(got).to eq(want)
+      end
+    end
+  end
+
+  context 'method `check`' do
+    success_tests.each do |t|
+      it "should fail with NOT_FOUND when #{t[:desc]}" do
+        blk = proc do
+          subject.check(HCReq.new(host: t[:host], service: t[:service]), nil)
+        end
+        expected_msg = /#{StatusCodes::NOT_FOUND}/
+        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      end
+    end
+  end
+
+  context 'method `clear_status`' do
+    success_tests.each do |t|
+      it "should fail after clearing status when #{t[:desc]}" do
+        subject.add_status(t[:host], t[:service], ServingStatus::NOT_SERVING)
+        got = subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                            nil)
+        want = HCResp.new(status: ServingStatus::NOT_SERVING)
+        expect(got).to eq(want)
+
+        subject.clear_status(t[:host], t[:service])
+        blk = proc do
+          subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                        nil)
+        end
+        expected_msg = /#{StatusCodes::NOT_FOUND}/
+        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      end
+    end
+  end
+
+  context 'method `clear_all`' do
+    it 'should return NOT_FOUND after being invoked' do
+      success_tests.each do |t|
+        subject.add_status(t[:host], t[:service], ServingStatus::NOT_SERVING)
+        got = subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                            nil)
+        want = HCResp.new(status: ServingStatus::NOT_SERVING)
+        expect(got).to eq(want)
+      end
+
+      subject.clear_all
+
+      success_tests.each do |t|
+        blk = proc do
+          subject.check(HCReq.new(host: t[:host], service: t[:service]), nil)
+        end
+        expected_msg = /#{StatusCodes::NOT_FOUND}/
+        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      end
+    end
+  end
+
+  describe 'running on RpcServer' do
+    RpcServer = GRPC::RpcServer
+    StatusCodes = GRPC::Core::StatusCodes
+    CheckerStub = Grpc::Health::Checker.rpc_stub_class
+
+    before(:each) do
+      @server_queue = GRPC::Core::CompletionQueue.new
+      server_host = '0.0.0.0:0'
+      @server = GRPC::Core::Server.new(@server_queue, nil)
+      server_port = @server.add_http2_port(server_host)
+      @host = "localhost:#{server_port}"
+      @ch = GRPC::Core::Channel.new(@host, nil)
+      @client_opts = { channel_override: @ch }
+      server_opts = {
+        server_override: @server,
+        completion_queue_override: @server_queue,
+        poll_period: 1
+      }
+      @srv = RpcServer.new(**server_opts)
+    end
+
+    after(:each) do
+      @srv.stop
+    end
+
+    it 'should receive the correct status', server: true do
+      @srv.handle(subject)
+      subject.add_status('', '', ServingStatus::NOT_SERVING)
+      t = Thread.new { @srv.run }
+      @srv.wait_till_running
+
+      stub = CheckerStub.new(@host, **@client_opts)
+      got = stub.check(HCReq.new)
+      want = HCResp.new(status: ServingStatus::NOT_SERVING)
+      expect(got).to eq(want)
+      @srv.stop
+      t.join
+    end
+
+    it 'should fail on unknown services', server: true do
+      @srv.handle(subject)
+      t = Thread.new { @srv.run }
+      @srv.wait_till_running
+      blk = proc do
+        stub = CheckerStub.new(@host, **@client_opts)
+        stub.check(HCReq.new(host: 'unknown', service: 'unknown'))
+      end
+      expected_msg = /#{StatusCodes::NOT_FOUND}/
+      expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      @srv.stop
+      t.join
+    end
+  end
+end
diff --git a/src/ruby/spec/spec_helper.rb b/src/ruby/spec/spec_helper.rb
index 270d2e97d3..c891c1bf5e 100644
--- a/src/ruby/spec/spec_helper.rb
+++ b/src/ruby/spec/spec_helper.rb
@@ -47,11 +47,23 @@ require 'rspec'
 require 'logging'
 require 'rspec/logging_helper'
 
+# GRPC is the general RPC module
+#
+# Configure its logging for fine-grained log control during test runs
+module GRPC
+  extend Logging.globally
+end
+Logging.logger.root.appenders = Logging.appenders.stdout
+Logging.logger.root.level = :info
+Logging.logger['GRPC'].level = :info
+Logging.logger['GRPC::ActiveCall'].level = :info
+Logging.logger['GRPC::BidiCall'].level = :info
+
 # Configure RSpec to capture log messages for each test. The output from the
 # logs will be stored in the @log_output variable. It is a StringIO instance.
 RSpec.configure do |config|
   include RSpec::LoggingHelper
-  config.capture_log_messages
+  config.capture_log_messages  # comment this out to see logs during test runs
 end
 
 RSpec::Expectations.configuration.warn_about_potential_false_positives = false