diff --git a/Makefile b/Makefile
index 13bc2f1..288f8a7 100644
--- a/Makefile
+++ b/Makefile
@@ -1946,12 +1946,12 @@
 $(GENDIR)/src/proto/grpc/lb/v1/load_balancer.pb.cc: src/proto/grpc/lb/v1/load_balancer.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/lb/v1/load_balancer.grpc.pb.cc: src/proto/grpc/lb/v1/load_balancer.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -1961,12 +1961,12 @@
 $(GENDIR)/src/proto/grpc/testing/compiler_test.pb.cc: src/proto/grpc/testing/compiler_test.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/compiler_test.grpc.pb.cc: src/proto/grpc/testing/compiler_test.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -1976,12 +1976,12 @@
 $(GENDIR)/src/proto/grpc/testing/control.pb.cc: src/proto/grpc/testing/control.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/payloads.pb.cc $(GENDIR)/src/proto/grpc/testing/stats.pb.cc
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/control.grpc.pb.cc: src/proto/grpc/testing/control.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/payloads.pb.cc $(GENDIR)/src/proto/grpc/testing/payloads.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/stats.pb.cc $(GENDIR)/src/proto/grpc/testing/stats.grpc.pb.cc
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -1991,12 +1991,12 @@
 $(GENDIR)/src/proto/grpc/testing/duplicate/echo_duplicate.pb.cc: src/proto/grpc/testing/duplicate/echo_duplicate.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/echo_messages.pb.cc
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/duplicate/echo_duplicate.grpc.pb.cc: src/proto/grpc/testing/duplicate/echo_duplicate.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/echo_messages.pb.cc $(GENDIR)/src/proto/grpc/testing/echo_messages.grpc.pb.cc
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2006,12 +2006,12 @@
 $(GENDIR)/src/proto/grpc/testing/echo.pb.cc: src/proto/grpc/testing/echo.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/echo_messages.pb.cc
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/echo.grpc.pb.cc: src/proto/grpc/testing/echo.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/echo_messages.pb.cc $(GENDIR)/src/proto/grpc/testing/echo_messages.grpc.pb.cc
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2021,12 +2021,12 @@
 $(GENDIR)/src/proto/grpc/testing/echo_messages.pb.cc: src/proto/grpc/testing/echo_messages.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/echo_messages.grpc.pb.cc: src/proto/grpc/testing/echo_messages.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2036,12 +2036,12 @@
 $(GENDIR)/src/proto/grpc/testing/empty.pb.cc: src/proto/grpc/testing/empty.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc: src/proto/grpc/testing/empty.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2051,12 +2051,12 @@
 $(GENDIR)/src/proto/grpc/testing/messages.pb.cc: src/proto/grpc/testing/messages.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc: src/proto/grpc/testing/messages.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2066,12 +2066,12 @@
 $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc: src/proto/grpc/testing/metrics.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc: src/proto/grpc/testing/metrics.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2081,12 +2081,12 @@
 $(GENDIR)/src/proto/grpc/testing/payloads.pb.cc: src/proto/grpc/testing/payloads.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/payloads.grpc.pb.cc: src/proto/grpc/testing/payloads.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2096,12 +2096,12 @@
 $(GENDIR)/src/proto/grpc/testing/services.pb.cc: src/proto/grpc/testing/services.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/control.pb.cc
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/services.grpc.pb.cc: src/proto/grpc/testing/services.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/control.pb.cc $(GENDIR)/src/proto/grpc/testing/control.grpc.pb.cc
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2111,12 +2111,12 @@
 $(GENDIR)/src/proto/grpc/testing/stats.pb.cc: src/proto/grpc/testing/stats.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/stats.grpc.pb.cc: src/proto/grpc/testing/stats.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) 
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 ifeq ($(NO_PROTOC),true)
@@ -2126,12 +2126,12 @@
 $(GENDIR)/src/proto/grpc/testing/test.pb.cc: src/proto/grpc/testing/test.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc
 	$(E) "[PROTOC]  Generating protobuf CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
 $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc: src/proto/grpc/testing/test.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc
 	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
 endif
 
 
@@ -4376,7 +4376,7 @@
     $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc \
     $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc \
     $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc \
-    test/cpp/interop/server_main.cc \
+    test/cpp/interop/interop_server.cc \
 
 PUBLIC_HEADERS_CXX += \
 
@@ -4422,7 +4422,7 @@
 -include $(LIBINTEROP_SERVER_MAIN_OBJS:.o=.dep)
 endif
 endif
-$(OBJDIR)/$(CONFIG)/test/cpp/interop/server_main.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
+$(OBJDIR)/$(CONFIG)/test/cpp/interop/interop_server.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 
 
 LIBQPS_SRC = \
@@ -14937,8 +14937,8 @@
 test/cpp/interop/client.cc: $(OPENSSL_DEP)
 test/cpp/interop/client_helper.cc: $(OPENSSL_DEP)
 test/cpp/interop/interop_client.cc: $(OPENSSL_DEP)
+test/cpp/interop/interop_server.cc: $(OPENSSL_DEP)
 test/cpp/interop/server_helper.cc: $(OPENSSL_DEP)
-test/cpp/interop/server_main.cc: $(OPENSSL_DEP)
 test/cpp/qps/client_async.cc: $(OPENSSL_DEP)
 test/cpp/qps/client_sync.cc: $(OPENSSL_DEP)
 test/cpp/qps/driver.cc: $(OPENSSL_DEP)
diff --git a/build.yaml b/build.yaml
index 38fb2c9..1e1253f 100644
--- a/build.yaml
+++ b/build.yaml
@@ -1117,7 +1117,7 @@
   - src/proto/grpc/testing/empty.proto
   - src/proto/grpc/testing/messages.proto
   - src/proto/grpc/testing/test.proto
-  - test/cpp/interop/server_main.cc
+  - test/cpp/interop/interop_server.cc
   deps:
   - interop_server_helper
   - grpc++_test_util
diff --git a/doc/interop-test-descriptions.md b/doc/interop-test-descriptions.md
index 7fd21c7..a4f9abe 100644
--- a/doc/interop-test-descriptions.md
+++ b/doc/interop-test-descriptions.md
@@ -68,14 +68,12 @@
 
 Server features:
 * [UnaryCall][]
-* [Compressable Payload][]
 
 Procedure:
  1. Client calls UnaryCall with:
 
     ```
     {
-      response_type: COMPRESSABLE
       response_size: 314159
       payload:{
         body: 271828 bytes of zeros
@@ -85,33 +83,106 @@
 
 Client asserts:
 * call was successful
-* response payload type is COMPRESSABLE
 * response payload body is 314159 bytes in size
 * clients are free to assert that the response payload body contents are zero
   and comparing the entire response message against a golden response
 
-### large_compressed_unary
+### client_compressed_unary
 
-This test verifies compressed unary calls succeed in sending messages. It
-sends one unary request for every payload type, with and without requesting a
-compressed response from the server.
+This test verifies the client can compress unary messages by sending two unary
+calls, for compressed and uncompressed payloads. It also sends an initial
+probing request to verify whether the server supports the [CompressedRequest][]
+feature by checking if the probing call fails with an `INVALID_ARGUMENT` status.
 
-In all scenarios, whether compression was actually performed is determined by
-the compression bit in the response's message flags.
+Server features:
+* [UnaryCall][]
+* [CompressedRequest][]
+
+Procedure:
+ 1. Client calls UnaryCall with the feature probe, an *uncompressed* message:
+    ```
+    {
+      expect_compressed:{
+        value: true
+      }
+      response_size: 314159
+      payload:{
+        body: 271828 bytes of zeros
+      }
+    }
+    ```
+
+ 1. Client calls UnaryCall with the *compressed* message:
+
+    ```
+    {
+      expect_compressed:{
+        value: true
+      }
+      response_size: 314159
+      payload:{
+        body: 271828 bytes of zeros
+      }
+    }
+    ```
+
+ 1. Client calls UnaryCall with the *uncompressed* message:
+
+    ```
+    {
+      expect_compressed:{
+        value: false
+      }
+      response_size: 314159
+      payload:{
+        body: 271828 bytes of zeros
+      }
+    }
+    ```
+
+    Client asserts:
+    * First call failed with `INVALID_ARGUMENT` status.
+    * Subsequent calls were successful.
+    * Response payload body is 314159 bytes in size.
+    * Clients are free to assert that the response payload body contents are
+      zeros and comparing the entire response message against a golden response.
+
+
+### server_compressed_unary
+
+This test verifies the server can compress unary messages. It sends two unary
+requests, expecting the server's response to be compressed or not according to
+the `response_compressed` boolean.
+
+Whether compression was actually performed is determined by the compression bit
+in the response's message flags. *Note that some languages may not have access
+to the message flags*.
 
 
 Server features:
 * [UnaryCall][]
-* [Compressable Payload][]
-* [Uncompressable Payload][]
+* [CompressedResponse][]
 
 Procedure:
- 1. Client calls UnaryCall with:
+ 1. Client calls UnaryCall with `SimpleRequest`:
 
     ```
     {
-      request_compressed_response: bool
-      response_type: COMPRESSABLE
+      response_compressed:{
+        value: true
+      }
+      response_size: 314159
+      payload:{
+        body: 271828 bytes of zeros
+      }
+    }
+    ```
+
+    ```
+    {
+      response_compressed:{
+        value: false
+      }
       response_size: 314159
       payload:{
         body: 271828 bytes of zeros
@@ -120,43 +191,21 @@
     ```
     Client asserts:
     * call was successful
-    * response payload type is COMPRESSABLE
-    * if `request_compressed_response` is false, the response MUST NOT have the
+    * when `response_compressed` is true, the response MUST have the
       compressed message flag set.
-    * if `request_compressed_response` is true, the response MUST have the
-      compressed message flag set.
-    * response payload body is 314159 bytes in size
+    * when `response_compressed` is false, the response MUST NOT have
+      the compressed message flag set.
+    * response payload body is 314159 bytes in size in both cases.
     * clients are free to assert that the response payload body contents are
       zero and comparing the entire response message against a golden response
 
 
- 2. Client calls UnaryCall with:
-    ```
-    {
-      request_compressed_response: bool
-      response_type: UNCOMPRESSABLE
-      response_size: 314159
-      payload:{
-        body: 271828 bytes of zeros
-      }
-    }
-    ```
-    Client asserts:
-    * call was successful
-    * response payload type is UNCOMPRESSABLE
-    * the response MAY have the compressed message flag set. Some
-      implementations will choose to compress the payload even when the output
-      size if larger than the input.
-    * response payload body is 314159 bytes in size
-
-
 ### client_streaming
 
 This test verifies that client-only streaming succeeds.
 
 Server features:
 * [StreamingInputCall][]
-* [Compressable Payload][]
 
 Procedure:
  1. Client calls StreamingInputCall
@@ -206,25 +255,81 @@
 * call was successful
 * response aggregated_payload_size is 74922
 
+
+### client_compressed_streaming
+
+This test verifies the client can compress requests on per-message basis by
+performing a two-request streaming call. It also sends an initial probing
+request to verify whether the server supports the [CompressedRequest][] feature
+by checking if the probing call fails with an `INVALID_ARGUMENT` status.
+
+Procedure:
+ 1. Client calls `StreamingInputCall` and sends the following feature-probing
+    *uncompressed* `StreamingInputCallRequest` message
+
+    ```
+    {
+      expect_compressed:{
+        value: true
+      }
+      payload:{
+        body: 27182 bytes of zeros
+      }
+    }
+    ```
+    If the call fails with `INVALID_ARGUMENT`, the test fails. Otherwise, we
+    continue.
+
+ 1. Client calls `StreamingInputCall` again, sending the *compressed* message
+
+    ```
+    {
+      expect_compressed:{
+        value: true
+      }
+      payload:{
+        body: 27182 bytes of zeros
+      }
+    }
+    ```
+
+ 1. And finally, the *uncompressed* message
+    ```
+    {
+      expect_compressed:{
+        value: false
+      }
+      payload:{
+        body: 45904 bytes of zeros
+      }
+    }
+    ```
+
+ 1. Client half-closes
+
+Client asserts:
+* First call fails with `INVALID_ARGUMENT`.
+* Next calls succeeds.
+* Response aggregated payload size is 73086.
+
+
 ### server_streaming
 
 This test verifies that server-only streaming succeeds.
 
 Server features:
 * [StreamingOutputCall][]
-* [Compressable Payload][]
 
 Procedure:
- 1. Client calls StreamingOutputCall with:
+ 1. Client calls StreamingOutputCall with `StreamingOutputCallRequest`:
 
     ```
     {
-      response_type:COMPRESSABLE
       response_parameters:{
         size: 31415
       }
       response_parameters:{
-        size: 59
+        size: 9
       }
       response_parameters:{
         size: 2653
@@ -238,103 +343,64 @@
 Client asserts:
 * call was successful
 * exactly four responses
-* response payloads are COMPRESSABLE
 * response payload bodies are sized (in order): 31415, 9, 2653, 58979
 * clients are free to assert that the response payload body contents are zero
   and comparing the entire response messages against golden responses
 
 ### server_compressed_streaming
 
-This test verifies that server-only compressed streaming succeeds.
+This test verifies that the server can compress streaming messages and disable
+compression on individual messages.
 
 Server features:
 * [StreamingOutputCall][]
-* [Compressable Payload][]
-* [Uncompressable Payload][]
+* [CompressedResponse][]
 
 
 Procedure:
- 1. Client calls StreamingOutputCall with:
+ 1. Client calls StreamingOutputCall with `StreamingOutputCallRequest`:
 
     ```
     {
-      request_compressed_response: bool
-      response_type:COMPRESSABLE
       response_parameters:{
+        compressed: {
+          value: true
+        }
         size: 31415
       }
       response_parameters:{
-        size: 59
-      }
-      response_parameters:{
-        size: 2653
-      }
-      response_parameters:{
-        size: 58979
+        compressed: {
+          value: false
+        }
+        size: 92653
       }
     }
     ```
 
     Client asserts:
     * call was successful
-    * exactly four responses
-    * response payloads are COMPRESSABLE
-    * if `request_compressed_response` is false, the response's messages MUST
+    * exactly two responses
+    * when `response_compressed` is false, the response's messages MUST
       NOT have the compressed message flag set.
-    * if `request_compressed_response` is true, the response's messages MUST
+    * when `response_compressed` is true, the response's messages MUST
       have the compressed message flag set.
-    * response payload bodies are sized (in order): 31415, 59, 2653, 58979
+    * response payload bodies are sized (in order): 31415, 92653
     * clients are free to assert that the response payload body contents are
       zero and comparing the entire response messages against golden responses
 
 
- 2. Client calls StreamingOutputCall with:
-
-    ```
-    {
-      request_compressed_response: bool
-      response_type:UNCOMPRESSABLE
-      response_parameters:{
-        size: 31415
-      }
-      response_parameters:{
-        size: 59
-      }
-      response_parameters:{
-        size: 2653
-      }
-      response_parameters:{
-        size: 58979
-      }
-    }
-    ```
-
-    Client asserts:
-    * call was successful
-    * exactly four responses
-    * response payloads are UNCOMPRESSABLE
-    * the response MAY have the compressed message flag set. Some
-      implementations will choose to compress the payload even when the output
-      size if larger than the input.
-    * response payload bodies are sized (in order): 31415, 59, 2653, 58979
-    * clients are free to assert that the body of the responses are identical to
-      the golden uncompressable data at `test/cpp/interop/rnd.dat`.
-
-
 ### ping_pong
 
 This test verifies that full duplex bidi is supported.
 
 Server features:
 * [FullDuplexCall][]
-* [Compressable Payload][]
 
 Procedure:
  1. Client calls FullDuplexCall with:
 
     ```
     {
-      response_type: COMPRESSABLE
       response_parameters:{
         size: 31415
       }
@@ -348,9 +414,8 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_parameters:{
-        size: 59
+        size: 9
       }
       payload:{
         body: 8 bytes of zeros
@@ -362,7 +427,6 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_parameters:{
         size: 2653
       }
@@ -376,7 +440,6 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_parameters:{
         size: 58979
       }
@@ -391,7 +454,6 @@
 Client asserts:
 * call was successful
 * exactly four responses
-* response payloads are COMPRESSABLE
 * response payload bodies are sized (in order): 31415, 9, 2653, 58979
 * clients are free to assert that the response payload body contents are zero
   and comparing the entire response messages against golden responses
@@ -421,12 +483,12 @@
 
 The test uses `--default_service_account` with GCE service account email and
 `--oauth_scope` with the OAuth scope to use. For testing against
-grpc-test.sandbox.googleapis.com, "https://www.googleapis.com/auth/xapi.zoo" should
+grpc-test.sandbox.googleapis.com, "https://www.googleapis.com/auth/xapi.zoo"
+should
 be passed in as `--oauth_scope`.
 
 Server features:
 * [UnaryCall][]
-* [Compressable Payload][]
 * [Echo Authenticated Username][]
 * [Echo OAuth Scope][]
 
@@ -436,7 +498,6 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_size: 314159
       payload:{
         body: 271828 bytes of zeros
@@ -448,7 +509,8 @@
 
 Client asserts:
 * call was successful
-* received SimpleResponse.username equals the value of `--default_service_account` flag
+* received SimpleResponse.username equals the value of
+  `--default_service_account` flag
 * received SimpleResponse.oauth_scope is in `--oauth_scope`
 * response payload body is 314159 bytes in size
 * clients are free to assert that the response payload body contents are zero
@@ -469,7 +531,6 @@
 
 Server features:
 * [UnaryCall][]
-* [Compressable Payload][]
 * [Echo Authenticated Username][]
 * [Echo OAuth Scope][]
 
@@ -479,7 +540,6 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_size: 314159
       payload:{
         body: 271828 bytes of zeros
@@ -492,7 +552,8 @@
 * call was successful
 * received SimpleResponse.username is not empty and is in the json key file used
 by the auth library. The client can optionally check the username matches the
-email address in the key file or equals the value of `--default_service_account` flag.
+email address in the key file or equals the value of `--default_service_account`
+flag.
 * response payload body is 314159 bytes in size
 * clients are free to assert that the response payload body contents are zero
   and comparing the entire response message against a golden response
@@ -518,18 +579,18 @@
 fetch the token, `--default_service_account` can be used to pass in GCE service
 account email.
 - uses the flag `--oauth_scope` for the oauth scope.  For testing against
-grpc-test.sandbox.googleapis.com, "https://www.googleapis.com/auth/xapi.zoo" should
-be passed as the `--oauth_scope`.
+grpc-test.sandbox.googleapis.com, "https://www.googleapis.com/auth/xapi.zoo"
+should be passed as the `--oauth_scope`.
 
 Server features:
 * [UnaryCall][]
-* [Compressable Payload][]
 * [Echo Authenticated Username][]
 * [Echo OAuth Scope][]
 
 Procedure:
  1. Client uses the auth library to obtain an authorization token
- 2. Client configures the channel to use AccessTokenCredentials with the access token obtained in step 1
+ 2. Client configures the channel to use AccessTokenCredentials with the access
+    token obtained in step 1
  3. Client calls UnaryCall with the following message
 
     ```
@@ -550,22 +611,21 @@
 
 Similar to the other auth tests, this test is only for cloud-to-prod path.
 
-This test verifies unary calls succeed in sending messages using a JWT or a service account
-credentials set on the RPC.
+This test verifies unary calls succeed in sending messages using a JWT or a
+service account credentials set on the RPC.
 
 The test
 - uses the flag `--service_account_key_file` with the path to a json key file
 downloaded from https://console.developers.google.com. Alternately, if using a
 usable auth implementation, it may specify the file location in the environment
 variable GOOGLE_APPLICATION_CREDENTIALS
-- optionally uses the flag `--oauth_scope` for the oauth scope if implementator 
+- optionally uses the flag `--oauth_scope` for the oauth scope if implementator
 wishes to use service account credential instead of JWT credential. For testing
-against grpc-test.sandbox.googleapis.com, oauth scope 
+against grpc-test.sandbox.googleapis.com, oauth scope
 "https://www.googleapis.com/auth/xapi.zoo" should be used.
 
 Server features:
 * [UnaryCall][]
-* [Compressable Payload][]
 * [Echo Authenticated Username][]
 * [Echo OAuth Scope][]
 
@@ -596,7 +656,6 @@
 Server features:
 * [UnaryCall][]
 * [FullDuplexCall][]
-* [Compressable Payload][]
 * [Echo Metadata][]
 
 Procedure:
@@ -611,7 +670,6 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_size: 314159
       payload:{
         body: 271828 bytes of zeros
@@ -630,7 +688,6 @@
 
     ```
     {
-      response_type: COMPRESSABLE
       response_size: 314159
       payload:{
         body: 271828 bytes of zeros
@@ -736,14 +793,12 @@
 
 Server features:
 * [FullDuplexCall][]
-* [Compressable Payload][]
 
 Procedure:
  1. Client starts FullDuplexCall with
 
     ```
     {
-      response_type: COMPRESSABLE
       response_parameters:{
         size: 31415
       }
@@ -887,6 +942,21 @@
 for the `SimpleRequest.response_type`. If the server does not support the
 `response_type`, then it should fail the RPC with `INVALID_ARGUMENT`.
 
+### CompressedResponse
+[CompressedResponse]: #compressedresponse
+
+When the client sets `response_compressed` to true, the server's response is
+sent back compressed. Note that `response_compressed` is present on both
+`SimpleRequest` (unary) and `StreamingOutputCallRequest` (streaming).
+
+### CompressedRequest
+[CompressedRequest]: #compressedrequest
+
+When the client sets `expect_compressed` to true, the server expects the client
+request to be compressed. If it's not, it fails the RPC with `INVALID_ARGUMENT`.
+Note that `response_compressed` is present on both `SimpleRequest` (unary) and
+`StreamingOutputCallRequest` (streaming).
+
 ### StreamingInputCall
 [StreamingInputCall]: #streaminginputcall
 
@@ -913,20 +983,6 @@
 respective ResponseParameters. After receiving half close and sending all
 responses, it closes with OK.
 
-### Compressable Payload
-[Compressable Payload]: #compressable-payload
-
-When the client requests COMPRESSABLE payload, the response includes a payload
-of the size requested containing all zeros and the payload type is
-COMPRESSABLE.
-
-### Uncompressable Payload
-[Uncompressable Payload]: #uncompressable-payload
-
-When the client requests UNCOMPRESSABLE payload, the response includes a payload
-of the size requested containing uncompressable data and the payload type is
-UNCOMPRESSABLE.
-
 ### Echo Status
 [Echo Status]: #echo-status
 When the client sends a response_status in the request payload, the server closes
diff --git a/src/proto/grpc/testing/messages.proto b/src/proto/grpc/testing/messages.proto
index e109015..e4e748a 100644
--- a/src/proto/grpc/testing/messages.proto
+++ b/src/proto/grpc/testing/messages.proto
@@ -32,19 +32,20 @@
 
 syntax = "proto3";
 
+import "google/protobuf/wrappers.proto";
+
 package grpc.testing;
 
+// DEPRECATED, don't use. To be removed shortly.
 // The type of payload that should be returned.
 enum PayloadType {
   // Compressable text format.
   COMPRESSABLE = 0;
-
-  // Uncompressable binary format.
-  UNCOMPRESSABLE = 1;
 }
 
 // A block of data, to simply increase gRPC message size.
 message Payload {
+  // DEPRECATED, don't use. To be removed shortly.
   // The type of data in body.
   PayloadType type = 1;
   // Primary contents of payload.
@@ -60,12 +61,12 @@
 
 // Unary request.
 message SimpleRequest {
+  // DEPRECATED, don't use. To be removed shortly.
   // Desired payload type in the response from the server.
   // If response_type is RANDOM, server randomly chooses one from other formats.
   PayloadType response_type = 1;
 
   // Desired payload size in the response from the server.
-  // If response_type is COMPRESSABLE, this denotes the size before compression.
   int32 response_size = 2;
 
   // Optional input payload sent along with the request.
@@ -77,11 +78,17 @@
   // Whether SimpleResponse should include OAuth scope.
   bool fill_oauth_scope = 5;
 
-  // Whether to request the server to compress the response.
-  bool request_compressed_response = 6;
+  // Whether to request the server to compress the response. This field is
+  // "nullable" in order to interoperate seamlessly with clients not able to
+  // implement the full compression tests by introspecting the call to verify
+  // the response's compression status.
+  google.protobuf.BoolValue response_compressed = 6;
 
   // Whether server should return a given status
   EchoStatus response_status = 7;
+
+  // Whether the server should expect this request to be compressed.
+  google.protobuf.BoolValue expect_compressed = 8;
 }
 
 // Unary response, as configured by the request.
@@ -100,6 +107,12 @@
   // Optional input payload sent along with the request.
   Payload payload = 1;
 
+  // Whether the server should expect this request to be compressed. This field
+  // is "nullable" in order to interoperate seamlessly with servers not able to
+  // implement the full compression tests by introspecting the call to verify
+  // the request's compression status.
+  google.protobuf.BoolValue expect_compressed = 2;
+
   // Not expecting any payload from the response.
 }
 
@@ -112,16 +125,22 @@
 // Configuration for a particular response.
 message ResponseParameters {
   // Desired payload sizes in responses from the server.
-  // If response_type is COMPRESSABLE, this denotes the size before compression.
   int32 size = 1;
 
   // Desired interval between consecutive responses in the response stream in
   // microseconds.
   int32 interval_us = 2;
+
+  // Whether to request the server to compress the response. This field is
+  // "nullable" in order to interoperate seamlessly with clients not able to
+  // implement the full compression tests by introspecting the call to verify
+  // the response's compression status.
+  google.protobuf.BoolValue compressed = 3;
 }
 
 // Server-streaming request.
 message StreamingOutputCallRequest {
+  // DEPRECATED, don't use. To be removed shortly.
   // Desired payload type in the response from the server.
   // If response_type is RANDOM, the payload from each response in the stream
   // might be of different types. This is to simulate a mixed type of payload
@@ -134,9 +153,6 @@
   // Optional input payload sent along with the request.
   Payload payload = 3;
 
-  // Whether to request the server to compress the response.
-  bool request_compressed_response = 6;
-
   // Whether server should return a given status
   EchoStatus response_status = 7;
 }
diff --git a/src/python/grpcio/commands.py b/src/python/grpcio/commands.py
index 3e974eb..7f9c292 100644
--- a/src/python/grpcio/commands.py
+++ b/src/python/grpcio/commands.py
@@ -182,6 +182,8 @@
           '--plugin=protoc-gen-python-grpc={}'.format(
               self.grpc_python_plugin_command),
           '-I {}'.format(GRPC_STEM),
+          '-I .'.format(GRPC_STEM),
+          '-I {}/third_party/protobuf/src'.format(GRPC_STEM),
           '--python_out={}'.format(PROTO_GEN_STEM),
           '--python-grpc_out={}'.format(PROTO_GEN_STEM),
       ] + [path]
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 0203954..0e3b992 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -1251,12 +1251,12 @@
   $(GENDIR)/${p}.pb.cc: ${p}.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) ${' '.join('$(GENDIR)/%s.pb.cc' % q for q in proto_deps.get(p, []))}
   	$(E) "[PROTOC]  Generating protobuf CC file from $<"
   	$(Q) mkdir -p `dirname $@`
-  	$(Q) $(PROTOC) --cpp_out=$(GENDIR) $<
+  	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --cpp_out=$(GENDIR) $<
 
   $(GENDIR)/${p}.grpc.pb.cc: ${p}.proto $(PROTOBUF_DEP) $(PROTOC_PLUGINS) ${' '.join('$(GENDIR)/%s.pb.cc $(GENDIR)/%s.grpc.pb.cc' % (q,q) for q in proto_deps.get(p, []))}
   	$(E) "[GRPC]    Generating gRPC's protobuf service CC file from $<"
   	$(Q) mkdir -p `dirname $@`
-  	$(Q) $(PROTOC) --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
+  	$(Q) $(PROTOC) -Ithird_party/protobuf/src -I. --grpc_out=$(GENDIR) --plugin=protoc-gen-grpc=$(BINDIR)/$(CONFIG)/grpc_cpp_plugin $<
   endif
 
   % endfor
diff --git a/test/cpp/interop/client.cc b/test/cpp/interop/client.cc
index addaf17..e8ae6ee 100644
--- a/test/cpp/interop/client.cc
+++ b/test/cpp/interop/client.cc
@@ -40,7 +40,9 @@
 #include <grpc++/client_context.h>
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/useful.h>
 
+#include "src/core/lib/support/string.h"
 #include "test/cpp/interop/client_helper.h"
 #include "test/cpp/interop/interop_client.h"
 #include "test/cpp/util/test_config.h"
@@ -52,30 +54,31 @@
 DEFINE_string(server_host_override, "foo.test.google.fr",
               "Override the server host which is sent in HTTP header");
 DEFINE_string(test_case, "large_unary",
-              "Configure different test cases. Valid options are: "
-              "empty_unary : empty (zero bytes) request and response; "
-              "large_unary : single request and (large) response; "
-              "large_compressed_unary : single request and compressed (large) "
-              "response; "
-              "client_streaming : request streaming with single response; "
-              "server_streaming : single request with response streaming; "
+              "Configure different test cases. Valid options are:\n\n"
+              "all : all test cases;\n"
+              "cancel_after_begin : cancel stream after starting it;\n"
+              "cancel_after_first_response: cancel on first response;\n"
+              "client_compressed_streaming : compressed request streaming with "
+              "client_compressed_unary : single compressed request;\n"
+              "client_streaming : request streaming with single response;\n"
+              "compute_engine_creds: large_unary with compute engine auth;\n"
+              "custom_metadata: server will echo custom metadata;\n"
+              "empty_stream : bi-di stream with no request/response;\n"
+              "empty_unary : empty (zero bytes) request and response;\n"
+              "half_duplex : half-duplex streaming;\n"
+              "jwt_token_creds: large_unary with JWT token auth;\n"
+              "large_unary : single request and (large) response;\n"
+              "oauth2_auth_token: raw oauth2 access token auth;\n"
+              "per_rpc_creds: raw oauth2 access token on a single rpc;\n"
+              "ping_pong : full-duplex streaming;\n"
+              "response streaming;\n"
               "server_compressed_streaming : single request with compressed "
-              "response streaming; "
-              "slow_consumer : single request with response; "
-              " streaming with slow client consumer; "
-              "half_duplex : half-duplex streaming; "
-              "ping_pong : full-duplex streaming; "
-              "cancel_after_begin : cancel stream after starting it; "
-              "cancel_after_first_response: cancel on first response; "
-              "timeout_on_sleeping_server: deadline exceeds on stream; "
-              "empty_stream : bi-di stream with no request/response; "
-              "compute_engine_creds: large_unary with compute engine auth; "
-              "jwt_token_creds: large_unary with JWT token auth; "
-              "oauth2_auth_token: raw oauth2 access token auth; "
-              "per_rpc_creds: raw oauth2 access token on a single rpc; "
-              "status_code_and_message: verify status code & message; "
-              "custom_metadata: server will echo custom metadata;"
-              "all : all of above.");
+              "server_compressed_unary : single compressed response;\n"
+              "server_streaming : single request with response streaming;\n"
+              "slow_consumer : single request with response streaming with "
+              "slow client consumer;\n"
+              "status_code_and_message: verify status code & message;\n"
+              "timeout_on_sleeping_server: deadline exceeds on stream;\n");
 DEFINE_string(default_service_account, "",
               "Email of GCE default service account");
 DEFINE_string(service_account_key_file, "",
@@ -104,14 +107,18 @@
     client.DoEmpty();
   } else if (FLAGS_test_case == "large_unary") {
     client.DoLargeUnary();
-  } else if (FLAGS_test_case == "large_compressed_unary") {
-    client.DoLargeCompressedUnary();
+  } else if (FLAGS_test_case == "server_compressed_unary") {
+    client.DoServerCompressedUnary();
+  } else if (FLAGS_test_case == "client_compressed_unary") {
+    client.DoClientCompressedUnary();
   } else if (FLAGS_test_case == "client_streaming") {
     client.DoRequestStreaming();
   } else if (FLAGS_test_case == "server_streaming") {
     client.DoResponseStreaming();
   } else if (FLAGS_test_case == "server_compressed_streaming") {
-    client.DoResponseCompressedStreaming();
+    client.DoServerCompressedStreaming();
+  } else if (FLAGS_test_case == "client_compressed_streaming") {
+    client.DoClientCompressedStreaming();
   } else if (FLAGS_test_case == "slow_consumer") {
     client.DoResponseStreamingWithSlowConsumer();
   } else if (FLAGS_test_case == "half_duplex") {
@@ -144,9 +151,12 @@
   } else if (FLAGS_test_case == "all") {
     client.DoEmpty();
     client.DoLargeUnary();
+    client.DoClientCompressedUnary();
+    client.DoServerCompressedUnary();
     client.DoRequestStreaming();
     client.DoResponseStreaming();
-    client.DoResponseCompressedStreaming();
+    client.DoClientCompressedStreaming();
+    client.DoServerCompressedStreaming();
     client.DoHalfDuplex();
     client.DoPingPong();
     client.DoCancelAfterBegin();
@@ -165,15 +175,35 @@
     }
     // compute_engine_creds only runs in GCE.
   } else {
-    gpr_log(
-        GPR_ERROR,
-        "Unsupported test case %s. Valid options are all|empty_unary|"
-        "large_unary|large_compressed_unary|client_streaming|server_streaming|"
-        "server_compressed_streaming|half_duplex|ping_pong|cancel_after_begin|"
-        "cancel_after_first_response|timeout_on_sleeping_server|empty_stream|"
-        "compute_engine_creds|jwt_token_creds|oauth2_auth_token|per_rpc_creds|"
-        "status_code_and_message|custom_metadata",
-        FLAGS_test_case.c_str());
+    const char* testcases[] = {"all",
+                               "cancel_after_begin",
+                               "cancel_after_first_response",
+                               "client_compressed_streaming",
+                               "client_compressed_unary",
+                               "client_streaming",
+                               "compute_engine_creds",
+                               "custom_metadata",
+                               "empty_stream",
+                               "empty_unary",
+                               "half_duplex",
+                               "jwt_token_creds",
+                               "large_unary",
+                               "oauth2_auth_token",
+                               "oauth2_auth_token",
+                               "per_rpc_creds",
+                               "per_rpc_creds",
+                               "ping_pong",
+                               "server_compressed_streaming",
+                               "server_compressed_unary",
+                               "server_streaming",
+                               "status_code_and_message",
+                               "timeout_on_sleeping_server"};
+    char* joined_testcases =
+        gpr_strjoin_sep(testcases, GPR_ARRAY_SIZE(testcases), "\n", NULL);
+
+    gpr_log(GPR_ERROR, "Unsupported test case %s. Valid options are\n%s",
+            FLAGS_test_case.c_str(), joined_testcases);
+    gpr_free(joined_testcases);
     ret = 1;
   }
 
diff --git a/test/cpp/interop/interop_client.cc b/test/cpp/interop/interop_client.cc
index 608f902..cfa17e5 100644
--- a/test/cpp/interop/interop_client.cc
+++ b/test/cpp/interop/interop_client.cc
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -57,7 +57,7 @@
 namespace {
 // The same value is defined by the Java client.
 const std::vector<int> request_stream_sizes = {27182, 8, 1828, 45904};
-const std::vector<int> response_stream_sizes = {31415, 59, 2653, 58979};
+const std::vector<int> response_stream_sizes = {31415, 9, 2653, 58979};
 const int kNumResponseMessages = 2000;
 const int kResponseMessageSize = 1030;
 const int kReceiveDelayMilliSeconds = 20;
@@ -67,28 +67,23 @@
 void NoopChecks(const InteropClientContextInspector& inspector,
                 const SimpleRequest* request, const SimpleResponse* response) {}
 
-void CompressionChecks(const InteropClientContextInspector& inspector,
-                       const SimpleRequest* request,
-                       const SimpleResponse* response) {
+void UnaryCompressionChecks(const InteropClientContextInspector& inspector,
+                            const SimpleRequest* request,
+                            const SimpleResponse* response) {
   const grpc_compression_algorithm received_compression =
       inspector.GetCallCompressionAlgorithm();
-  if (request->request_compressed_response() &&
-      received_compression == GRPC_COMPRESS_NONE) {
-    if (request->request_compressed_response() &&
-        received_compression == GRPC_COMPRESS_NONE) {
+  if (request->response_compressed().value()) {
+    if (received_compression == GRPC_COMPRESS_NONE) {
       // Requested some compression, got NONE. This is an error.
       gpr_log(GPR_ERROR,
               "Failure: Requested compression but got uncompressed response "
               "from server.");
       abort();
     }
-  }
-  if (!request->request_compressed_response()) {
-    GPR_ASSERT(!(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS));
-  } else if (request->response_type() == PayloadType::COMPRESSABLE) {
-    // requested compression and compressable response => results should always
-    // be compressed.
     GPR_ASSERT(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS);
+  } else {
+    // Didn't request compression -> make sure the response is uncompressed
+    GPR_ASSERT(!(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS));
   }
 }
 }  // namespace
@@ -190,11 +185,16 @@
                                       CheckerFn custom_checks_fn) {
   ClientContext context;
   InteropClientContextInspector inspector(context);
-  // If the request doesn't already specify the response type, default to
-  // COMPRESSABLE.
   request->set_response_size(kLargeResponseSize);
   grpc::string payload(kLargeRequestSize, '\0');
   request->mutable_payload()->set_body(payload.c_str(), kLargeRequestSize);
+  if (request->has_expect_compressed()) {
+    if (request->expect_compressed().value()) {
+      context.set_compression_algorithm(GRPC_COMPRESS_GZIP);
+    } else {
+      context.set_compression_algorithm(GRPC_COMPRESS_NONE);
+    }
+  }
 
   Status s = serviceStub_.Get()->UnaryCall(&context, *request, response);
   if (!AssertStatusOk(s)) {
@@ -204,27 +204,8 @@
   custom_checks_fn(inspector, request, response);
 
   // Payload related checks.
-  GPR_ASSERT(response->payload().type() == request->response_type());
-  switch (response->payload().type()) {
-    case PayloadType::COMPRESSABLE:
-      GPR_ASSERT(response->payload().body() ==
-                 grpc::string(kLargeResponseSize, '\0'));
-      break;
-    case PayloadType::UNCOMPRESSABLE: {
-      // We don't really check anything: We can't assert that the payload is
-      // uncompressed because it's the server's prerogative to decide on that,
-      // and different implementations decide differently (ie, Java always
-      // compresses when requested to do so, whereas C core throws away the
-      // compressed payload if the output is larger than the input).
-      // In addition, we don't compare the actual random bytes received because
-      // asserting that data is sent/received properly isn't the purpose of this
-      // test. Moreover, different implementations are also free to use
-      // different sets of random bytes.
-    } break;
-    default:
-      GPR_ASSERT(false);
-  }
-
+  GPR_ASSERT(response->payload().body() ==
+             grpc::string(kLargeResponseSize, '\0'));
   return true;
 }
 
@@ -237,7 +218,6 @@
   SimpleResponse response;
   request.set_fill_username(true);
   request.set_fill_oauth_scope(true);
-  request.set_response_type(PayloadType::COMPRESSABLE);
 
   if (!PerformLargeUnary(&request, &response)) {
     return false;
@@ -311,7 +291,6 @@
   SimpleRequest request;
   SimpleResponse response;
   request.set_fill_username(true);
-  request.set_response_type(PayloadType::COMPRESSABLE);
 
   if (!PerformLargeUnary(&request, &response)) {
     return false;
@@ -327,7 +306,6 @@
   gpr_log(GPR_DEBUG, "Sending a large unary rpc...");
   SimpleRequest request;
   SimpleResponse response;
-  request.set_response_type(PayloadType::COMPRESSABLE);
   if (!PerformLargeUnary(&request, &response)) {
     return false;
   }
@@ -335,32 +313,73 @@
   return true;
 }
 
-bool InteropClient::DoLargeCompressedUnary() {
-  const bool request_compression[] = {false, true};
-  const PayloadType payload_types[] = {COMPRESSABLE, UNCOMPRESSABLE};
-  for (size_t i = 0; i < GPR_ARRAY_SIZE(payload_types); i++) {
-    for (size_t j = 0; j < GPR_ARRAY_SIZE(request_compression); j++) {
-      char* log_suffix;
-      gpr_asprintf(&log_suffix, "(compression=%s; payload=%s)",
-                   request_compression[j] ? "true" : "false",
-                   PayloadType_Name(payload_types[i]).c_str());
+bool InteropClient::DoClientCompressedUnary() {
+  // Probing for compression-checks support.
+  ClientContext probe_context;
+  SimpleRequest probe_req;
+  SimpleResponse probe_res;
 
-      gpr_log(GPR_DEBUG, "Sending a large compressed unary rpc %s.",
-              log_suffix);
-      SimpleRequest request;
-      SimpleResponse response;
-      request.set_response_type(payload_types[i]);
-      request.set_request_compressed_response(request_compression[j]);
+  probe_context.set_compression_algorithm(GRPC_COMPRESS_NONE);
+  probe_req.mutable_expect_compressed()->set_value(true);  // lies!
 
-      if (!PerformLargeUnary(&request, &response, CompressionChecks)) {
-        gpr_log(GPR_ERROR, "Large compressed unary failed %s", log_suffix);
-        gpr_free(log_suffix);
-        return false;
-      }
+  probe_req.set_response_size(kLargeResponseSize);
+  probe_req.mutable_payload()->set_body(grpc::string(kLargeRequestSize, '\0'));
 
-      gpr_log(GPR_DEBUG, "Large compressed unary done %s.", log_suffix);
+  gpr_log(GPR_DEBUG, "Sending probe for compressed unary request.");
+  const Status s =
+      serviceStub_.Get()->UnaryCall(&probe_context, probe_req, &probe_res);
+  if (s.error_code() != grpc::StatusCode::INVALID_ARGUMENT) {
+    // The server isn't able to evaluate incoming compression, making the rest
+    // of this test moot.
+    gpr_log(GPR_DEBUG, "Compressed unary request probe failed");
+    return false;
+  }
+  gpr_log(GPR_DEBUG, "Compressed unary request probe succeeded. Proceeding.");
+
+  const std::vector<bool> compressions = {true, false};
+  for (size_t i = 0; i < compressions.size(); i++) {
+    char* log_suffix;
+    gpr_asprintf(&log_suffix, "(compression=%s)",
+                 compressions[i] ? "true" : "false");
+
+    gpr_log(GPR_DEBUG, "Sending compressed unary request %s.", log_suffix);
+    SimpleRequest request;
+    SimpleResponse response;
+    request.mutable_expect_compressed()->set_value(compressions[i]);
+    if (!PerformLargeUnary(&request, &response, UnaryCompressionChecks)) {
+      gpr_log(GPR_ERROR, "Compressed unary request failed %s", log_suffix);
       gpr_free(log_suffix);
+      return false;
     }
+
+    gpr_log(GPR_DEBUG, "Compressed unary request failed %s", log_suffix);
+    gpr_free(log_suffix);
+  }
+
+  return true;
+}
+
+bool InteropClient::DoServerCompressedUnary() {
+  const std::vector<bool> compressions = {true, false};
+  for (size_t i = 0; i < compressions.size(); i++) {
+    char* log_suffix;
+    gpr_asprintf(&log_suffix, "(compression=%s)",
+                 compressions[i] ? "true" : "false");
+
+    gpr_log(GPR_DEBUG, "Sending unary request for compressed response %s.",
+            log_suffix);
+    SimpleRequest request;
+    SimpleResponse response;
+    request.mutable_response_compressed()->set_value(compressions[i]);
+
+    if (!PerformLargeUnary(&request, &response, UnaryCompressionChecks)) {
+      gpr_log(GPR_ERROR, "Request for compressed unary failed %s", log_suffix);
+      gpr_free(log_suffix);
+      return false;
+    }
+
+    gpr_log(GPR_DEBUG, "Request for compressed unary failed %s", log_suffix);
+    gpr_free(log_suffix);
   }
 
   return true;
@@ -387,7 +406,7 @@
       serviceStub_.Get()->StreamingInputCall(&context, &response));
 
   int aggregated_payload_size = 0;
-  for (unsigned int i = 0; i < request_stream_sizes.size(); ++i) {
+  for (size_t i = 0; i < request_stream_sizes.size(); ++i) {
     Payload* payload = request.mutable_payload();
     payload->set_body(grpc::string(request_stream_sizes[i], '\0'));
     if (!stream->Write(request)) {
@@ -396,7 +415,7 @@
     }
     aggregated_payload_size += request_stream_sizes[i];
   }
-  stream->WritesDone();
+  GPR_ASSERT(stream->WritesDone());
 
   Status s = stream->Finish();
   if (!AssertStatusOk(s)) {
@@ -446,92 +465,131 @@
   return true;
 }
 
-bool InteropClient::DoResponseCompressedStreaming() {
-  const bool request_compression[] = {false, true};
-  const PayloadType payload_types[] = {COMPRESSABLE, UNCOMPRESSABLE};
-  for (size_t i = 0; i < GPR_ARRAY_SIZE(payload_types); i++) {
-    for (size_t j = 0; j < GPR_ARRAY_SIZE(request_compression); j++) {
-      ClientContext context;
-      InteropClientContextInspector inspector(context);
-      StreamingOutputCallRequest request;
+bool InteropClient::DoClientCompressedStreaming() {
+  // Probing for compression-checks support.
+  ClientContext probe_context;
+  StreamingInputCallRequest probe_req;
+  StreamingInputCallResponse probe_res;
 
-      char* log_suffix;
-      gpr_asprintf(&log_suffix, "(compression=%s; payload=%s)",
-                   request_compression[j] ? "true" : "false",
-                   PayloadType_Name(payload_types[i]).c_str());
+  probe_context.set_compression_algorithm(GRPC_COMPRESS_NONE);
+  probe_req.mutable_expect_compressed()->set_value(true);  // lies!
+  probe_req.mutable_payload()->set_body(grpc::string(27182, '\0'));
 
-      gpr_log(GPR_DEBUG, "Receiving response streaming rpc %s.", log_suffix);
+  gpr_log(GPR_DEBUG, "Sending probe for compressed streaming request.");
 
-      request.set_response_type(payload_types[i]);
-      request.set_request_compressed_response(request_compression[j]);
+  std::unique_ptr<ClientWriter<StreamingInputCallRequest>> probe_stream(
+      serviceStub_.Get()->StreamingInputCall(&probe_context, &probe_res));
 
-      for (size_t k = 0; k < response_stream_sizes.size(); ++k) {
-        ResponseParameters* response_parameter =
-            request.add_response_parameters();
-        response_parameter->set_size(response_stream_sizes[k]);
-      }
-      StreamingOutputCallResponse response;
+  if (!probe_stream->Write(probe_req)) {
+    gpr_log(GPR_ERROR, "%s(): stream->Write() failed", __func__);
+    return TransientFailureOrAbort();
+  }
+  Status s = probe_stream->Finish();
+  if (s.error_code() != grpc::StatusCode::INVALID_ARGUMENT) {
+    // The server isn't able to evaluate incoming compression, making the rest
+    // of this test moot.
+    gpr_log(GPR_DEBUG, "Compressed streaming request probe failed");
+    return false;
+  }
+  gpr_log(GPR_DEBUG,
+          "Compressed streaming request probe succeeded. Proceeding.");
 
-      std::unique_ptr<ClientReader<StreamingOutputCallResponse>> stream(
-          serviceStub_.Get()->StreamingOutputCall(&context, request));
+  ClientContext context;
+  StreamingInputCallRequest request;
+  StreamingInputCallResponse response;
 
-      size_t k = 0;
-      while (stream->Read(&response)) {
-        // Payload related checks.
-        GPR_ASSERT(response.payload().type() == request.response_type());
-        switch (response.payload().type()) {
-          case PayloadType::COMPRESSABLE:
-            GPR_ASSERT(response.payload().body() ==
-                       grpc::string(response_stream_sizes[k], '\0'));
-            break;
-          case PayloadType::UNCOMPRESSABLE:
-            break;
-          default:
-            GPR_ASSERT(false);
-        }
+  context.set_compression_algorithm(GRPC_COMPRESS_GZIP);
+  std::unique_ptr<ClientWriter<StreamingInputCallRequest>> stream(
+      serviceStub_.Get()->StreamingInputCall(&context, &response));
 
-        // Compression related checks.
-        if (request.request_compressed_response()) {
-          GPR_ASSERT(inspector.GetCallCompressionAlgorithm() >
-                     GRPC_COMPRESS_NONE);
-          if (request.response_type() == PayloadType::COMPRESSABLE) {
-            // requested compression and compressable response => results should
-            // always be compressed.
-            GPR_ASSERT(inspector.GetMessageFlags() &
-                       GRPC_WRITE_INTERNAL_COMPRESS);
-          }
-        } else {
-          // requested *no* compression.
-          GPR_ASSERT(
-              !(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS));
-        }
-
-        ++k;
-      }
-
-      gpr_log(GPR_DEBUG, "Response streaming done %s.", log_suffix);
-      gpr_free(log_suffix);
-
-      if (k < response_stream_sizes.size()) {
-        // stream->Read() failed before reading all the expected messages. This
-        // is most likely due to a connection failure.
-        gpr_log(GPR_ERROR,
-                "DoResponseCompressedStreaming(): Responses read (k=%" PRIuPTR
-                ") is "
-                "less than the expected messages (i.e "
-                "response_stream_sizes.size() (%" PRIuPTR ")). (i=%" PRIuPTR
-                ", j=%" PRIuPTR ")",
-                k, response_stream_sizes.size(), i, j);
-        return TransientFailureOrAbort();
-      }
-
-      Status s = stream->Finish();
-      if (!AssertStatusOk(s)) {
-        return false;
-      }
-    }
+  request.mutable_payload()->set_body(grpc::string(27182, '\0'));
+  request.mutable_expect_compressed()->set_value(true);
+  gpr_log(GPR_DEBUG, "Sending streaming request with compression enabled");
+  if (!stream->Write(request)) {
+    gpr_log(GPR_ERROR, "%s(): stream->Write() failed", __func__);
+    return TransientFailureOrAbort();
   }
 
+  WriteOptions wopts;
+  wopts.set_no_compression();
+  request.mutable_payload()->set_body(grpc::string(45904, '\0'));
+  request.mutable_expect_compressed()->set_value(false);
+  gpr_log(GPR_DEBUG, "Sending streaming request with compression disabled");
+  if (!stream->Write(request, wopts)) {
+    gpr_log(GPR_ERROR, "%s(): stream->Write() failed", __func__);
+    return TransientFailureOrAbort();
+  }
+  GPR_ASSERT(stream->WritesDone());
+
+  s = stream->Finish();
+  if (!AssertStatusOk(s)) {
+    return false;
+  }
+
+  return true;
+}
+
+bool InteropClient::DoServerCompressedStreaming() {
+  const std::vector<bool> compressions = {true, false};
+  const std::vector<int> sizes = {31415, 92653};
+
+  ClientContext context;
+  InteropClientContextInspector inspector(context);
+  StreamingOutputCallRequest request;
+
+  for (size_t i = 0; i < compressions.size(); i++) {
+    for (size_t j = 0; j < sizes.size(); j++) {
+      char* log_suffix;
+      gpr_asprintf(&log_suffix, "(compression=%s; size=%d)",
+                   compressions[i] ? "true" : "false", sizes[j]);
+
+      gpr_log(GPR_DEBUG, "Sending request streaming rpc %s.", log_suffix);
+      gpr_free(log_suffix);
+
+      ResponseParameters* const response_parameter =
+          request.add_response_parameters();
+      response_parameter->mutable_compressed()->set_value(compressions[i]);
+      response_parameter->set_size(sizes[j]);
+    }
+  }
+  std::unique_ptr<ClientReader<StreamingOutputCallResponse>> stream(
+      serviceStub_.Get()->StreamingOutputCall(&context, request));
+
+  size_t k = 0;
+  StreamingOutputCallResponse response;
+  while (stream->Read(&response)) {
+    // Payload size checks.
+    GPR_ASSERT(response.payload().body() ==
+               grpc::string(request.response_parameters(k).size(), '\0'));
+
+    // Compression checks.
+    GPR_ASSERT(request.response_parameters(k).has_compressed());
+    if (request.response_parameters(k).compressed().value()) {
+      GPR_ASSERT(inspector.GetCallCompressionAlgorithm() > GRPC_COMPRESS_NONE);
+      GPR_ASSERT(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS);
+    } else {
+      // requested *no* compression.
+      GPR_ASSERT(!(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS));
+    }
+    ++k;
+  }
+
+  if (k < response_stream_sizes.size()) {
+    // stream->Read() failed before reading all the expected messages. This
+    // is most likely due to a connection failure.
+    gpr_log(GPR_ERROR,
+            "%s(): Responses read (k=%" PRIuPTR
+            ") is "
+            "less than the expected messages (i.e "
+            "response_stream_sizes.size() (%" PRIuPTR ")).",
+            __func__, k, response_stream_sizes.size());
+    return TransientFailureOrAbort();
+  }
+
+  Status s = stream->Finish();
+  if (!AssertStatusOk(s)) {
+    return false;
+  }
   return true;
 }
 
@@ -632,7 +690,6 @@
       stream(serviceStub_.Get()->FullDuplexCall(&context));
 
   StreamingOutputCallRequest request;
-  request.set_response_type(PayloadType::COMPRESSABLE);
   ResponseParameters* response_parameter = request.add_response_parameters();
   Payload* payload = request.mutable_payload();
   StreamingOutputCallResponse response;
@@ -699,7 +756,6 @@
       stream(serviceStub_.Get()->FullDuplexCall(&context));
 
   StreamingOutputCallRequest request;
-  request.set_response_type(PayloadType::COMPRESSABLE);
   ResponseParameters* response_parameter = request.add_response_parameters();
   response_parameter->set_size(31415);
   request.mutable_payload()->set_body(grpc::string(27182, '\0'));
@@ -839,7 +895,6 @@
         stream(serviceStub_.Get()->FullDuplexCall(&context));
 
     StreamingOutputCallRequest request;
-    request.set_response_type(PayloadType::COMPRESSABLE);
     ResponseParameters* response_parameter = request.add_response_parameters();
     response_parameter->set_size(kLargeResponseSize);
     grpc::string payload(kLargeRequestSize, '\0');
diff --git a/test/cpp/interop/interop_client.h b/test/cpp/interop/interop_client.h
index c8d6810..eb886fc 100644
--- a/test/cpp/interop/interop_client.h
+++ b/test/cpp/interop/interop_client.h
@@ -64,12 +64,14 @@
 
   bool DoEmpty();
   bool DoLargeUnary();
-  bool DoLargeCompressedUnary();
+  bool DoServerCompressedUnary();
+  bool DoClientCompressedUnary();
   bool DoPingPong();
   bool DoHalfDuplex();
   bool DoRequestStreaming();
   bool DoResponseStreaming();
-  bool DoResponseCompressedStreaming();
+  bool DoServerCompressedStreaming();
+  bool DoClientCompressedStreaming();
   bool DoResponseStreamingWithSlowConsumer();
   bool DoCancelAfterBegin();
   bool DoCancelAfterFirstResponse();
diff --git a/test/cpp/interop/server_main.cc b/test/cpp/interop/interop_server.cc
similarity index 73%
rename from test/cpp/interop/server_main.cc
rename to test/cpp/interop/interop_server.cc
index 062857f..f0a182f 100644
--- a/test/cpp/interop/server_main.cc
+++ b/test/cpp/interop/interop_server.cc
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,6 +48,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
 
+#include "src/core/lib/transport/byte_stream.h"
 #include "src/proto/grpc/testing/empty.grpc.pb.h"
 #include "src/proto/grpc/testing/messages.grpc.pb.h"
 #include "src/proto/grpc/testing/test.grpc.pb.h"
@@ -64,10 +65,10 @@
 using grpc::ServerReader;
 using grpc::ServerReaderWriter;
 using grpc::ServerWriter;
+using grpc::WriteOptions;
 using grpc::SslServerCredentialsOptions;
 using grpc::testing::InteropServerContextInspector;
 using grpc::testing::Payload;
-using grpc::testing::PayloadType;
 using grpc::testing::SimpleRequest;
 using grpc::testing::SimpleResponse;
 using grpc::testing::StreamingInputCallRequest;
@@ -78,7 +79,6 @@
 using grpc::Status;
 
 static bool got_sigint = false;
-static const char* kRandomFile = "test/cpp/interop/rnd.dat";
 
 const char kEchoInitialMetadataKey[] = "x-grpc-test-echo-initial";
 const char kEchoTrailingBinMetadataKey[] = "x-grpc-test-echo-trailing-bin";
@@ -110,34 +110,41 @@
   }
 }
 
-bool SetPayload(PayloadType response_type, int size, Payload* payload) {
-  payload->set_type(response_type);
-  switch (response_type) {
-    case PayloadType::COMPRESSABLE: {
-      std::unique_ptr<char[]> body(new char[size]());
-      payload->set_body(body.get(), size);
-    } break;
-    case PayloadType::UNCOMPRESSABLE: {
-      std::unique_ptr<char[]> body(new char[size]());
-      std::ifstream rnd_file(kRandomFile);
-      GPR_ASSERT(rnd_file.good());
-      rnd_file.read(body.get(), size);
-      GPR_ASSERT(!rnd_file.eof());  // Requested more rnd bytes than available
-      payload->set_body(body.get(), size);
-    } break;
-    default:
-      GPR_ASSERT(false);
-  }
+bool SetPayload(int size, Payload* payload) {
+  std::unique_ptr<char[]> body(new char[size]());
+  payload->set_body(body.get(), size);
   return true;
 }
 
-template <typename RequestType>
-void SetResponseCompression(ServerContext* context,
-                            const RequestType& request) {
-  if (request.request_compressed_response()) {
-    // Any level would do, let's go for HIGH because we are overachievers.
-    context->set_compression_level(GRPC_COMPRESS_LEVEL_HIGH);
+bool CheckExpectedCompression(const ServerContext& context,
+                              const bool compression_expected) {
+  const InteropServerContextInspector inspector(context);
+  const grpc_compression_algorithm received_compression =
+      inspector.GetCallCompressionAlgorithm();
+
+  if (compression_expected) {
+    if (received_compression == GRPC_COMPRESS_NONE) {
+      // Expected some compression, got NONE. This is an error.
+      gpr_log(GPR_ERROR,
+              "Expected compression but got uncompressed request from client.");
+      return false;
+    }
+    if (!(inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS)) {
+      gpr_log(GPR_ERROR,
+              "Failure: Requested compression in a compressable request, but "
+              "compression bit in message flags not set.");
+      return false;
+    }
+  } else {
+    // Didn't expect compression -> make sure the request is uncompressed
+    if (inspector.GetMessageFlags() & GRPC_WRITE_INTERNAL_COMPRESS) {
+      gpr_log(GPR_ERROR,
+              "Failure: Didn't requested compression, but compression bit in "
+              "message flags set.");
+      return false;
+    }
   }
+  return true;
 }
 
 class TestServiceImpl : public TestService::Service {
@@ -151,11 +158,26 @@
   Status UnaryCall(ServerContext* context, const SimpleRequest* request,
                    SimpleResponse* response) {
     MaybeEchoMetadata(context);
-    SetResponseCompression(context, *request);
+    if (request->has_response_compressed()) {
+      const bool compression_requested = request->response_compressed().value();
+      gpr_log(GPR_DEBUG, "Request for compression (%s) present for %s",
+              compression_requested ? "enabled" : "disabled", __func__);
+      if (compression_requested) {
+        // Any level would do, let's go for HIGH because we are overachievers.
+        context->set_compression_level(GRPC_COMPRESS_LEVEL_HIGH);
+      } else {
+        context->set_compression_level(GRPC_COMPRESS_LEVEL_NONE);
+      }
+    }
+    if (!CheckExpectedCompression(*context,
+                                  request->expect_compressed().value())) {
+      return Status(grpc::StatusCode::INVALID_ARGUMENT,
+                    "Compressed request expectation not met.");
+    }
     if (request->response_size() > 0) {
-      if (!SetPayload(request->response_type(), request->response_size(),
-                      response->mutable_payload())) {
-        return Status(grpc::StatusCode::INTERNAL, "Error creating payload.");
+      if (!SetPayload(request->response_size(), response->mutable_payload())) {
+        return Status(grpc::StatusCode::INVALID_ARGUMENT,
+                      "Error creating payload.");
       }
     }
 
@@ -171,15 +193,26 @@
   Status StreamingOutputCall(
       ServerContext* context, const StreamingOutputCallRequest* request,
       ServerWriter<StreamingOutputCallResponse>* writer) {
-    SetResponseCompression(context, *request);
     StreamingOutputCallResponse response;
+    // Compress by default. Disabled on a per-message basis.
+    context->set_compression_level(GRPC_COMPRESS_LEVEL_HIGH);
     bool write_success = true;
     for (int i = 0; write_success && i < request->response_parameters_size();
          i++) {
-      if (!SetPayload(request->response_type(),
-                      request->response_parameters(i).size(),
+      if (!SetPayload(request->response_parameters(i).size(),
                       response.mutable_payload())) {
-        return Status(grpc::StatusCode::INTERNAL, "Error creating payload.");
+        return Status(grpc::StatusCode::INVALID_ARGUMENT,
+                      "Error creating payload.");
+      }
+      WriteOptions wopts;
+      if (request->response_parameters(i).has_compressed()) {
+        const bool compression_requested =
+            request->response_parameters(i).compressed().value();
+        gpr_log(GPR_DEBUG, "Request for compression (%s) present for %s",
+                compression_requested ? "enabled" : "disabled", __func__);
+        if (!compression_requested) {
+          wopts.set_no_compression();
+        }  // else, compression is already enabled via the context.
       }
       int time_us;
       if ((time_us = request->response_parameters(i).interval_us()) > 0) {
@@ -204,6 +237,11 @@
     StreamingInputCallRequest request;
     int aggregated_payload_size = 0;
     while (reader->Read(&request)) {
+      if (!CheckExpectedCompression(*context,
+                                    request.expect_compressed().value())) {
+        return Status(grpc::StatusCode::INVALID_ARGUMENT,
+                      "Compressed request expectation not met.");
+      }
       if (request.has_payload()) {
         aggregated_payload_size += request.payload().body().size();
       }
@@ -221,7 +259,6 @@
     StreamingOutputCallResponse response;
     bool write_success = true;
     while (write_success && stream->Read(&request)) {
-      SetResponseCompression(context, request);
       if (request.response_parameters_size() != 0) {
         response.mutable_payload()->set_type(request.payload().type());
         response.mutable_payload()->set_body(
diff --git a/test/cpp/interop/rnd.dat b/test/cpp/interop/rnd.dat
deleted file mode 100644
index 8c7f38f..0000000
--- a/test/cpp/interop/rnd.dat
+++ /dev/null
Binary files differ
diff --git a/test/cpp/interop/server_helper.cc b/test/cpp/interop/server_helper.cc
index c6d891a..8b0b511 100644
--- a/test/cpp/interop/server_helper.cc
+++ b/test/cpp/interop/server_helper.cc
@@ -72,6 +72,10 @@
   return grpc_call_test_only_get_encodings_accepted_by_peer(context_.call_);
 }
 
+uint32_t InteropServerContextInspector::GetMessageFlags() const {
+  return grpc_call_test_only_get_message_flags(context_.call_);
+}
+
 std::shared_ptr<const AuthContext>
 InteropServerContextInspector::GetAuthContext() const {
   return context_.auth_context();
diff --git a/test/cpp/interop/server_helper.h b/test/cpp/interop/server_helper.h
index 12865e4..a1da14a 100644
--- a/test/cpp/interop/server_helper.h
+++ b/test/cpp/interop/server_helper.h
@@ -54,6 +54,7 @@
   bool IsCancelled() const;
   grpc_compression_algorithm GetCallCompressionAlgorithm() const;
   uint32_t GetEncodingsAcceptedByClient() const;
+  uint32_t GetMessageFlags() const;
 
  private:
   const ::grpc::ServerContext& context_;
diff --git a/test/cpp/interop/stress_interop_client.cc b/test/cpp/interop/stress_interop_client.cc
index aa95682..1d5fc80 100644
--- a/test/cpp/interop/stress_interop_client.cc
+++ b/test/cpp/interop/stress_interop_client.cc
@@ -138,8 +138,12 @@
       is_success = interop_client_->DoLargeUnary();
       break;
     }
-    case LARGE_COMPRESSED_UNARY: {
-      is_success = interop_client_->DoLargeCompressedUnary();
+    case CLIENT_COMPRESSED_UNARY: {
+      is_success = interop_client_->DoClientCompressedUnary();
+      break;
+    }
+    case CLIENT_COMPRESSED_STREAMING: {
+      is_success = interop_client_->DoClientCompressedStreaming();
       break;
     }
     case CLIENT_STREAMING: {
@@ -150,8 +154,12 @@
       is_success = interop_client_->DoResponseStreaming();
       break;
     }
+    case SERVER_COMPRESSED_UNARY: {
+      is_success = interop_client_->DoServerCompressedUnary();
+      break;
+    }
     case SERVER_COMPRESSED_STREAMING: {
-      is_success = interop_client_->DoResponseCompressedStreaming();
+      is_success = interop_client_->DoServerCompressedStreaming();
       break;
     }
     case SLOW_CONSUMER: {
diff --git a/test/cpp/interop/stress_interop_client.h b/test/cpp/interop/stress_interop_client.h
index aa93b58..cf6a713 100644
--- a/test/cpp/interop/stress_interop_client.h
+++ b/test/cpp/interop/stress_interop_client.h
@@ -51,29 +51,33 @@
 
 enum TestCaseType {
   UNKNOWN_TEST = -1,
-  EMPTY_UNARY = 0,
-  LARGE_UNARY = 1,
-  LARGE_COMPRESSED_UNARY = 2,
-  CLIENT_STREAMING = 3,
-  SERVER_STREAMING = 4,
-  SERVER_COMPRESSED_STREAMING = 5,
-  SLOW_CONSUMER = 6,
-  HALF_DUPLEX = 7,
-  PING_PONG = 8,
-  CANCEL_AFTER_BEGIN = 9,
-  CANCEL_AFTER_FIRST_RESPONSE = 10,
-  TIMEOUT_ON_SLEEPING_SERVER = 11,
-  EMPTY_STREAM = 12,
-  STATUS_CODE_AND_MESSAGE = 13,
-  CUSTOM_METADATA = 14
+  EMPTY_UNARY,
+  LARGE_UNARY,
+  CLIENT_COMPRESSED_UNARY,
+  CLIENT_COMPRESSED_STREAMING,
+  CLIENT_STREAMING,
+  SERVER_STREAMING,
+  SERVER_COMPRESSED_UNARY,
+  SERVER_COMPRESSED_STREAMING,
+  SLOW_CONSUMER,
+  HALF_DUPLEX,
+  PING_PONG,
+  CANCEL_AFTER_BEGIN,
+  CANCEL_AFTER_FIRST_RESPONSE,
+  TIMEOUT_ON_SLEEPING_SERVER,
+  EMPTY_STREAM,
+  STATUS_CODE_AND_MESSAGE,
+  CUSTOM_METADATA
 };
 
 const vector<pair<TestCaseType, grpc::string>> kTestCaseList = {
     {EMPTY_UNARY, "empty_unary"},
     {LARGE_UNARY, "large_unary"},
-    {LARGE_COMPRESSED_UNARY, "large_compressed_unary"},
+    {CLIENT_COMPRESSED_UNARY, "client_compressed_unary"},
+    {CLIENT_COMPRESSED_STREAMING, "client_compressed_streaming"},
     {CLIENT_STREAMING, "client_streaming"},
     {SERVER_STREAMING, "server_streaming"},
+    {SERVER_COMPRESSED_UNARY, "server_compressed_unary"},
     {SERVER_COMPRESSED_STREAMING, "server_compressed_streaming"},
     {SLOW_CONSUMER, "slow_consumer"},
     {HALF_DUPLEX, "half_duplex"},
diff --git a/tools/run_tests/sources_and_headers.json b/tools/run_tests/sources_and_headers.json
index 57e3bd6..e273808 100644
--- a/tools/run_tests/sources_and_headers.json
+++ b/tools/run_tests/sources_and_headers.json
@@ -4624,7 +4624,7 @@
     "language": "c++", 
     "name": "interop_server_main", 
     "src": [
-      "test/cpp/interop/server_main.cc"
+      "test/cpp/interop/interop_server.cc"
     ], 
     "third_party": false, 
     "type": "lib"
diff --git a/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj b/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj
index 075750a..18971d6 100644
--- a/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj
+++ b/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj
@@ -171,7 +171,7 @@
     </ClCompile>
     <ClInclude Include="$(SolutionDir)\..\src\proto\grpc\testing\test.grpc.pb.h">
     </ClInclude>
-    <ClCompile Include="$(SolutionDir)\..\test\cpp\interop\server_main.cc">
+    <ClCompile Include="$(SolutionDir)\..\test\cpp\interop\interop_server.cc">
     </ClCompile>
   </ItemGroup>
   <ItemGroup>
diff --git a/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj.filters b/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj.filters
index 51a6b9e..4ee8135 100644
--- a/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj.filters
+++ b/vsprojects/vcxproj/interop_server_main/interop_server_main.vcxproj.filters
@@ -10,7 +10,7 @@
     <ClCompile Include="$(SolutionDir)\..\src\proto\grpc\testing\test.proto">
       <Filter>src\proto\grpc\testing</Filter>
     </ClCompile>
-    <ClCompile Include="$(SolutionDir)\..\test\cpp\interop\server_main.cc">
+    <ClCompile Include="$(SolutionDir)\..\test\cpp\interop\interop_server.cc">
       <Filter>test\cpp\interop</Filter>
     </ClCompile>
   </ItemGroup>