diff --git a/trunk/configure b/trunk/configure
index 208e38226..9950c5279 100755
--- a/trunk/configure
+++ b/trunk/configure
@@ -142,7 +142,7 @@ KERNEL_OBJS="${MODULE_OBJS[@]}"
 MODULE_ID="PROTOCOL" 
 MODULE_DEPENDS=("CORE" "KERNEL") 
 ModuleLibIncs=(${SRS_OBJS})
-MODULE_FILES=("srs_protocol_amf0")
+MODULE_FILES=("srs_protocol_amf0" "srs_protocol_io")
 MODULE_DIR="src/protocol" . auto/modules.sh
 PROTOCOL_OBJS="${MODULE_OBJS[@]}"
 #
diff --git a/trunk/src/app/srs_core_client.cpp b/trunk/src/app/srs_core_client.cpp
index bb25dd5dd..0145f71e4 100644
--- a/trunk/src/app/srs_core_client.cpp
+++ b/trunk/src/app/srs_core_client.cpp
@@ -41,6 +41,7 @@ using namespace std;
 #include <srs_core_hls.hpp>
 #include <srs_core_http.hpp>
 #include <srs_core_bandwidth.hpp>
+#include <srs_core_socket.hpp>
 
 SrsClient::SrsClient(SrsServer* srs_server, st_netfd_t client_stfd)
 	: SrsConnection(srs_server, client_stfd)
@@ -48,7 +49,8 @@ SrsClient::SrsClient(SrsServer* srs_server, st_netfd_t client_stfd)
 	ip = NULL;
 	req = new SrsRequest();
 	res = new SrsResponse();
-	rtmp = new SrsRtmp(client_stfd);
+	skt = new SrsSocket(client_stfd);
+	rtmp = new SrsRtmp(skt);
 	refer = new SrsRefer();
 #ifdef SRS_HTTP	
 	http_hooks = new SrsHttpHooks();
@@ -66,6 +68,7 @@ SrsClient::~SrsClient()
 	srs_freep(req);
 	srs_freep(res);
 	srs_freep(rtmp);
+	srs_freep(skt);
 	srs_freep(refer);
 #ifdef SRS_HTTP	
 	srs_freep(http_hooks);
diff --git a/trunk/src/app/srs_core_client.hpp b/trunk/src/app/srs_core_client.hpp
index f2c94edb1..d72f59f2a 100644
--- a/trunk/src/app/srs_core_client.hpp
+++ b/trunk/src/app/srs_core_client.hpp
@@ -41,6 +41,7 @@ class SrsSource;
 class SrsRefer;
 class SrsConsumer;
 class SrsCommonMessage;
+class SrsSocket;
 #ifdef SRS_HTTP	
 class SrsHttpHooks;
 #endif
@@ -55,6 +56,7 @@ private:
 	char* ip;
 	SrsRequest* req;
 	SrsResponse* res;
+	SrsSocket* skt;
 	SrsRtmp* rtmp;
 	SrsRefer* refer;
 #ifdef SRS_HTTP	
diff --git a/trunk/src/app/srs_core_forward.cpp b/trunk/src/app/srs_core_forward.cpp
index 289173bdb..d2787e072 100644
--- a/trunk/src/app/srs_core_forward.cpp
+++ b/trunk/src/app/srs_core_forward.cpp
@@ -37,11 +37,13 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_kernel_config.hpp>
 #include <srs_core_source.hpp>
 #include <srs_core_autofree.hpp>
+#include <srs_core_socket.hpp>
 
 SrsForwarder::SrsForwarder(SrsSource* _source)
 {
 	source = _source;
 	
+	io = NULL;
 	client = NULL;
 	stfd = NULL;
 	stream_id = 0;
@@ -127,6 +129,7 @@ void SrsForwarder::on_unpublish()
 	close_underlayer_socket();
 	
 	srs_freep(client);
+	srs_freep(io);
 }
 
 int SrsForwarder::on_meta_data(SrsSharedPtrMessage* metadata)
@@ -250,9 +253,12 @@ int SrsForwarder::connect_server()
         srs_error("st_netfd_open_socket failed. ret=%d", ret);
         return ret;
     }
-
+    
 	srs_freep(client);
-	client = new SrsRtmpClient(stfd);
+	srs_freep(io);
+	
+	io = new SrsSocket(stfd);
+	client = new SrsRtmpClient(io);
 	
 	// connect to server.
 	std::string ip = srs_dns_resolve(server);
diff --git a/trunk/src/app/srs_core_forward.hpp b/trunk/src/app/srs_core_forward.hpp
index afc1217af..857e80356 100644
--- a/trunk/src/app/srs_core_forward.hpp
+++ b/trunk/src/app/srs_core_forward.hpp
@@ -34,6 +34,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_core_st.hpp>
 #include <srs_core_thread.hpp>
 
+class ISrsProtocolReaderWriter;
 class SrsSharedPtrMessage;
 class SrsOnMetaDataPacket;
 class SrsMessageQueue;
@@ -59,6 +60,7 @@ private:
 	SrsThread* pthread;
 private:
 	SrsSource* source;
+	ISrsProtocolReaderWriter* io;
 	SrsRtmpClient* client;
 	SrsRtmpJitter* jitter;
 	SrsMessageQueue* queue;
diff --git a/trunk/src/app/srs_core_handshake.cpp b/trunk/src/app/srs_core_handshake.cpp
index 9f05133df..979906657 100644
--- a/trunk/src/app/srs_core_handshake.cpp
+++ b/trunk/src/app/srs_core_handshake.cpp
@@ -29,7 +29,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_kernel_error.hpp>
 #include <srs_kernel_log.hpp>
 #include <srs_core_autofree.hpp>
-#include <srs_core_socket.hpp>
+#include <srs_protocol_io.hpp>
 
 void srs_random_generate(char* bytes, int size)
 {
@@ -1067,7 +1067,7 @@ SrsSimpleHandshake::~SrsSimpleHandshake()
 {
 }
 
-int SrsSimpleHandshake::handshake_with_client(SrsSocket& skt, SrsComplexHandshake& complex_hs)
+int SrsSimpleHandshake::handshake_with_client(ISrsProtocolReaderWriter* skt, SrsComplexHandshake& complex_hs)
 {
 	int ret = ERROR_SUCCESS;
 	
@@ -1075,7 +1075,7 @@ int SrsSimpleHandshake::handshake_with_client(SrsSocket& skt, SrsComplexHandshak
     
     char* c0c1 = new char[1537];
     SrsAutoFree(char, c0c1, true);
-    if ((ret = skt.read_fully(c0c1, 1537, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->read_fully(c0c1, 1537, &nsize)) != ERROR_SUCCESS) {
         srs_warn("read c0c1 failed. ret=%d", ret);
         return ret;
     }
@@ -1106,7 +1106,7 @@ int SrsSimpleHandshake::handshake_with_client(SrsSocket& skt, SrsComplexHandshak
     SrsAutoFree(char, s0s1s2, true);
 	// plain text required.
     s0s1s2[0] = 0x03;
-    if ((ret = skt.write(s0s1s2, 3073, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->write(s0s1s2, 3073, &nsize)) != ERROR_SUCCESS) {
         srs_warn("simple handshake send s0s1s2 failed. ret=%d", ret);
         return ret;
     }
@@ -1114,7 +1114,7 @@ int SrsSimpleHandshake::handshake_with_client(SrsSocket& skt, SrsComplexHandshak
     
     char* c2 = new char[1536];
     SrsAutoFree(char, c2, true);
-    if ((ret = skt.read_fully(c2, 1536, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->read_fully(c2, 1536, &nsize)) != ERROR_SUCCESS) {
         srs_warn("simple handshake read c2 failed. ret=%d", ret);
         return ret;
     }
@@ -1125,7 +1125,7 @@ int SrsSimpleHandshake::handshake_with_client(SrsSocket& skt, SrsComplexHandshak
 	return ret;
 }
 
-int SrsSimpleHandshake::handshake_with_server(SrsSocket& skt, SrsComplexHandshake& complex_hs)
+int SrsSimpleHandshake::handshake_with_server(ISrsProtocolReaderWriter* skt, SrsComplexHandshake& complex_hs)
 {
 	int ret = ERROR_SUCCESS;
     
@@ -1151,7 +1151,7 @@ int SrsSimpleHandshake::handshake_with_server(SrsSocket& skt, SrsComplexHandshak
 	// plain text required.
 	c0c1[0] = 0x03;
 	
-    if ((ret = skt.write(c0c1, 1537, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->write(c0c1, 1537, &nsize)) != ERROR_SUCCESS) {
         srs_warn("write c0c1 failed. ret=%d", ret);
         return ret;
     }
@@ -1159,7 +1159,7 @@ int SrsSimpleHandshake::handshake_with_server(SrsSocket& skt, SrsComplexHandshak
 	
 	char* s0s1s2 = new char[3073];
     SrsAutoFree(char, s0s1s2, true);
-    if ((ret = skt.read_fully(s0s1s2, 3073, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->read_fully(s0s1s2, 3073, &nsize)) != ERROR_SUCCESS) {
         srs_warn("simple handshake recv s0s1s2 failed. ret=%d", ret);
         return ret;
     }
@@ -1175,7 +1175,7 @@ int SrsSimpleHandshake::handshake_with_server(SrsSocket& skt, SrsComplexHandshak
     char* c2 = new char[1536];
     SrsAutoFree(char, c2, true);
 	srs_random_generate(c2, 1536);
-    if ((ret = skt.write(c2, 1536, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->write(c2, 1536, &nsize)) != ERROR_SUCCESS) {
         srs_warn("simple handshake write c2 failed. ret=%d", ret);
         return ret;
     }
@@ -1195,12 +1195,12 @@ SrsComplexHandshake::~SrsComplexHandshake()
 }
 
 #ifndef SRS_SSL
-int SrsComplexHandshake::handshake_with_client(SrsSocket& /*skt*/, char* /*_c1*/)
+int SrsComplexHandshake::handshake_with_client(ISrsProtocolReaderWriter* /*skt*/, char* /*_c1*/)
 {
 	return ERROR_RTMP_TRY_SIMPLE_HS;
 }
 #else
-int SrsComplexHandshake::handshake_with_client(SrsSocket& skt, char* _c1)
+int SrsComplexHandshake::handshake_with_client(ISrsProtocolReaderWriter* skt, char* _c1)
 {
 	int ret = ERROR_SUCCESS;
 
@@ -1258,7 +1258,7 @@ int SrsComplexHandshake::handshake_with_client(SrsSocket& skt, char* _c1)
 	s0s1s2[0] = 0x03;
 	s1.dump(s0s1s2 + 1);
 	s2.dump(s0s1s2 + 1537);
-    if ((ret = skt.write(s0s1s2, 3073, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->write(s0s1s2, 3073, &nsize)) != ERROR_SUCCESS) {
         srs_warn("complex handshake send s0s1s2 failed. ret=%d", ret);
         return ret;
     }
@@ -1267,7 +1267,7 @@ int SrsComplexHandshake::handshake_with_client(SrsSocket& skt, char* _c1)
     // recv c2
     char* c2 = new char[1536];
     SrsAutoFree(char, c2, true);
-    if ((ret = skt.read_fully(c2, 1536, &nsize)) != ERROR_SUCCESS) {
+    if ((ret = skt->read_fully(c2, 1536, &nsize)) != ERROR_SUCCESS) {
         srs_warn("complex handshake read c2 failed. ret=%d", ret);
         return ret;
     }
@@ -1278,12 +1278,12 @@ int SrsComplexHandshake::handshake_with_client(SrsSocket& skt, char* _c1)
 #endif
 
 #ifndef SRS_SSL
-int SrsComplexHandshake::handshake_with_server(SrsSocket& /*skt*/)
+int SrsComplexHandshake::handshake_with_server(ISrsProtocolReaderWriter* /*skt*/)
 {
 	return ERROR_RTMP_TRY_SIMPLE_HS;
 }
 #else
-int SrsComplexHandshake::handshake_with_server(SrsSocket& /*skt*/)
+int SrsComplexHandshake::handshake_with_server(ISrsProtocolReaderWriter* /*skt*/)
 {
 	int ret = ERROR_SUCCESS;
 	
diff --git a/trunk/src/app/srs_core_handshake.hpp b/trunk/src/app/srs_core_handshake.hpp
index 06686fc1e..4b7484c5e 100644
--- a/trunk/src/app/srs_core_handshake.hpp
+++ b/trunk/src/app/srs_core_handshake.hpp
@@ -30,7 +30,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <srs_core.hpp>
 
-class SrsSocket;
+class ISrsProtocolReaderWriter;
 class SrsComplexHandshake;
 
 /**
@@ -47,8 +47,8 @@ public:
 	* @param complex_hs, try complex handshake first, 
 	* 		if failed, rollback to simple handshake.
 	*/
-	virtual int handshake_with_client(SrsSocket& skt, SrsComplexHandshake& complex_hs);
-	virtual int handshake_with_server(SrsSocket& skt, SrsComplexHandshake& complex_hs);
+	virtual int handshake_with_client(ISrsProtocolReaderWriter* io, SrsComplexHandshake& complex_hs);
+	virtual int handshake_with_server(ISrsProtocolReaderWriter* io, SrsComplexHandshake& complex_hs);
 };
 
 /**
@@ -71,8 +71,8 @@ public:
 	* 	try simple handshake if error is ERROR_RTMP_TRY_SIMPLE_HS,
 	* 	otherwise, disconnect
 	*/
-	virtual int handshake_with_client(SrsSocket& skt, char* _c1);
-	virtual int handshake_with_server(SrsSocket& skt);
+	virtual int handshake_with_client(ISrsProtocolReaderWriter* io, char* _c1);
+	virtual int handshake_with_server(ISrsProtocolReaderWriter* io);
 };
 
 #endif
\ No newline at end of file
diff --git a/trunk/src/app/srs_core_protocol.cpp b/trunk/src/app/srs_core_protocol.cpp
index f802c47af..9b333d212 100644
--- a/trunk/src/app/srs_core_protocol.cpp
+++ b/trunk/src/app/srs_core_protocol.cpp
@@ -26,7 +26,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_kernel_log.hpp>
 #include <srs_protocol_amf0.hpp>
 #include <srs_kernel_error.hpp>
-#include <srs_core_socket.hpp>
+#include <srs_protocol_io.hpp>
 #include <srs_kernel_buffer.hpp>
 #include <srs_kernel_stream.hpp>
 #include <srs_core_autofree.hpp>
@@ -290,11 +290,10 @@ SrsProtocol::AckWindowSize::AckWindowSize()
 	ack_window_size = acked_size = 0;
 }
 
-SrsProtocol::SrsProtocol(st_netfd_t client_stfd)
+SrsProtocol::SrsProtocol(ISrsProtocolReaderWriter* io)
 {
-	stfd = client_stfd;
 	buffer = new SrsBuffer();
-	skt = new SrsSocket(stfd);
+	skt = io;
 	
 	in_chunk_size = out_chunk_size = RTMP_DEFAULT_CHUNK_SIZE;
 }
@@ -311,7 +310,6 @@ SrsProtocol::~SrsProtocol()
 	chunk_streams.clear();
 	
 	srs_freep(buffer);
-	srs_freep(skt);
 }
 
 string SrsProtocol::get_request_name(double transcationId)
@@ -720,7 +718,7 @@ int SrsProtocol::recv_interlaced_message(SrsCommonMessage** pmsg)
 	// when we got a chunk header, we should increase the timeout,
 	// or we maybe timeout and disconnect the client.
 	int64_t timeout_us = skt->get_recv_timeout();
-	if (timeout_us != (int64_t)ST_UTIME_NO_TIMEOUT) {
+	if (!skt->is_never_timeout(timeout_us)) {
 		int64_t pkt_timeout_us = srs_max(timeout_us, SRS_MIN_RECV_TIMEOUT_US);
 		skt->set_recv_timeout(pkt_timeout_us);
 		srs_verbose("change recv timeout_us "
@@ -764,7 +762,7 @@ int SrsProtocol::recv_interlaced_message(SrsCommonMessage** pmsg)
 	}
 	
 	// reset the recv timeout
-	if (timeout_us != (int64_t)ST_UTIME_NO_TIMEOUT) {
+	if (!skt->is_never_timeout(timeout_us)) {
 		skt->set_recv_timeout(timeout_us);
 		srs_verbose("reset recv timeout_us to %"PRId64"", timeout_us);
 	}
diff --git a/trunk/src/app/srs_core_protocol.hpp b/trunk/src/app/srs_core_protocol.hpp
index 7aaf83849..8e09925bf 100644
--- a/trunk/src/app/srs_core_protocol.hpp
+++ b/trunk/src/app/srs_core_protocol.hpp
@@ -33,7 +33,6 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <map>
 #include <string>
 
-#include <srs_core_st.hpp>
 #include <srs_kernel_log.hpp>
 #include <srs_kernel_error.hpp>
 
@@ -76,7 +75,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // when error, encoder sleep for a while and retry.
 #define SRS_ENCODER_SLEEP_US (int64_t)(3*1000*1000LL)
 
-class SrsSocket;
+class ISrsProtocolReaderWriter;
 class SrsBuffer;
 class SrsPacket;
 class SrsStream;
@@ -123,8 +122,7 @@ private:
 	};
 // peer in/out
 private:
-	st_netfd_t stfd;
-	SrsSocket* skt;
+	ISrsProtocolReaderWriter* skt;
 	char* pp;
 	/**
 	* requests sent out, used to build the response.
@@ -144,7 +142,11 @@ private:
 	char out_header_fmt3[RTMP_MAX_FMT3_HEADER_SIZE];
 	int32_t out_chunk_size;
 public:
-	SrsProtocol(st_netfd_t client_stfd);
+	/**
+	* use io to create the protocol stack,
+	* @param io, provides io interfaces, user must free it.
+	*/
+	SrsProtocol(ISrsProtocolReaderWriter* io);
 	virtual ~SrsProtocol();
 public:
 	std::string get_request_name(double transcationId);
@@ -1214,6 +1216,15 @@ protected:
 * @pmsg, user must free it. NULL if not success.
 * @ppacket, store in the pmsg, user must never free it. NULL if not success.
 * @remark, only when success, user can use and must free the pmsg/ppacket.
+* for example:
+ 		SrsCommonMessage* msg = NULL;
+		SrsConnectAppResPacket* pkt = NULL;
+		if ((ret = srs_rtmp_expect_message<SrsConnectAppResPacket>(protocol, &msg, &pkt)) != ERROR_SUCCESS) {
+			return ret;
+		}
+		// use pkt
+* user should never recv message and convert it, use this method instead.
+* if need to set timeout, use set timeout of SrsProtocol.
 */
 template<class T>
 int srs_rtmp_expect_message(SrsProtocol* protocol, SrsCommonMessage** pmsg, T** ppacket)
diff --git a/trunk/src/app/srs_core_rtmp.cpp b/trunk/src/app/srs_core_rtmp.cpp
index 5cb452582..27ad3dba4 100644
--- a/trunk/src/app/srs_core_rtmp.cpp
+++ b/trunk/src/app/srs_core_rtmp.cpp
@@ -25,7 +25,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <srs_kernel_log.hpp>
 #include <srs_kernel_error.hpp>
-#include <srs_core_socket.hpp>
+#include <srs_protocol_io.hpp>
 #include <srs_core_protocol.hpp>
 #include <srs_core_autofree.hpp>
 #include <srs_protocol_amf0.hpp>
@@ -197,10 +197,10 @@ SrsResponse::~SrsResponse()
 {
 }
 
-SrsRtmpClient::SrsRtmpClient(st_netfd_t _stfd)
+SrsRtmpClient::SrsRtmpClient(ISrsProtocolReaderWriter* skt)
 {
-	stfd = _stfd;
-	protocol = new SrsProtocol(stfd);
+	io = skt;
+	protocol = new SrsProtocol(skt);
 }
 
 SrsRtmpClient::~SrsRtmpClient()
@@ -251,15 +251,10 @@ int SrsRtmpClient::send_message(ISrsMessage* msg)
 int SrsRtmpClient::handshake()
 {
 	int ret = ERROR_SUCCESS;
-	
-    SrsSocket skt(stfd);
-    
-    skt.set_recv_timeout(protocol->get_recv_timeout());
-    skt.set_send_timeout(protocol->get_send_timeout());
     
     SrsComplexHandshake complex_hs;
     SrsSimpleHandshake simple_hs;
-    if ((ret = simple_hs.handshake_with_server(skt, complex_hs)) != ERROR_SUCCESS) {
+    if ((ret = simple_hs.handshake_with_server(io, complex_hs)) != ERROR_SUCCESS) {
         return ret;
     }
     
@@ -449,10 +444,10 @@ int SrsRtmpClient::publish(string stream, int stream_id)
 	return ret;
 }
 
-SrsRtmp::SrsRtmp(st_netfd_t client_stfd)
+SrsRtmp::SrsRtmp(ISrsProtocolReaderWriter* skt)
 {
-	protocol = new SrsProtocol(client_stfd);
-	stfd = client_stfd;
+	io = skt;
+	protocol = new SrsProtocol(skt);
 }
 
 SrsRtmp::~SrsRtmp()
@@ -518,15 +513,10 @@ int SrsRtmp::send_message(ISrsMessage* msg)
 int SrsRtmp::handshake()
 {
 	int ret = ERROR_SUCCESS;
-	
-    SrsSocket skt(stfd);
-    
-    skt.set_recv_timeout(protocol->get_recv_timeout());
-    skt.set_send_timeout(protocol->get_send_timeout());
     
     SrsComplexHandshake complex_hs;
     SrsSimpleHandshake simple_hs;
-    if ((ret = simple_hs.handshake_with_client(skt, complex_hs)) != ERROR_SUCCESS) {
+    if ((ret = simple_hs.handshake_with_client(io, complex_hs)) != ERROR_SUCCESS) {
         return ret;
     }
     
diff --git a/trunk/src/app/srs_core_rtmp.hpp b/trunk/src/app/srs_core_rtmp.hpp
index 8c79661ca..bea35619a 100644
--- a/trunk/src/app/srs_core_rtmp.hpp
+++ b/trunk/src/app/srs_core_rtmp.hpp
@@ -35,6 +35,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_core_st.hpp>
 
 class SrsProtocol;
+class ISrsProtocolReaderWriter;
 class ISrsMessage;
 class SrsCommonMessage;
 class SrsCreateStreamPacket;
@@ -115,9 +116,9 @@ class SrsRtmpClient
 {
 protected:
 	SrsProtocol* protocol;
-	st_netfd_t stfd;
+	ISrsProtocolReaderWriter* io;
 public:
-	SrsRtmpClient(st_netfd_t _stfd);
+	SrsRtmpClient(ISrsProtocolReaderWriter* skt);
 	virtual ~SrsRtmpClient();
 public:
 	virtual void set_recv_timeout(int64_t timeout_us);
@@ -145,9 +146,9 @@ class SrsRtmp
 {
 private:
 	SrsProtocol* protocol;
-	st_netfd_t stfd;
+	ISrsProtocolReaderWriter* io;
 public:
-	SrsRtmp(st_netfd_t client_stfd);
+	SrsRtmp(ISrsProtocolReaderWriter* skt);
 	virtual ~SrsRtmp();
 public:
 	virtual SrsProtocol* get_protocol();
diff --git a/trunk/src/app/srs_core_socket.cpp b/trunk/src/app/srs_core_socket.cpp
index 90ec123db..6fab06020 100644
--- a/trunk/src/app/srs_core_socket.cpp
+++ b/trunk/src/app/srs_core_socket.cpp
@@ -37,6 +37,11 @@ SrsSocket::~SrsSocket()
 {
 }
 
+bool SrsSocket::is_never_timeout(int64_t timeout_us)
+{
+	return timeout_us == (int64_t)ST_UTIME_NO_TIMEOUT;
+}
+
 void SrsSocket::set_recv_timeout(int64_t timeout_us)
 {
 	recv_timeout = timeout_us;
diff --git a/trunk/src/app/srs_core_socket.hpp b/trunk/src/app/srs_core_socket.hpp
index 38f0368e5..31ee28742 100644
--- a/trunk/src/app/srs_core_socket.hpp
+++ b/trunk/src/app/srs_core_socket.hpp
@@ -31,13 +31,13 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_core.hpp>
 
 #include <srs_core_st.hpp>
-#include <srs_kernel_buffer.hpp>
+#include <srs_protocol_io.hpp>
 
 /**
 * the socket provides TCP socket over st,
 * that is, the sync socket mechanism.
 */
-class SrsSocket : public ISrsBufferReader
+class SrsSocket : public ISrsProtocolReaderWriter
 {
 private:
 	int64_t recv_timeout;
@@ -50,6 +50,7 @@ public:
     SrsSocket(st_netfd_t client_stfd);
     virtual ~SrsSocket();
 public:
+	virtual bool is_never_timeout(int64_t timeout_us);
 	virtual void set_recv_timeout(int64_t timeout_us);
 	virtual int64_t get_recv_timeout();
 	virtual void set_send_timeout(int64_t timeout_us);
diff --git a/trunk/src/kernel/srs_kernel_buffer.hpp b/trunk/src/kernel/srs_kernel_buffer.hpp
index f652309f0..309f96680 100644
--- a/trunk/src/kernel/srs_kernel_buffer.hpp
+++ b/trunk/src/kernel/srs_kernel_buffer.hpp
@@ -40,6 +40,7 @@ class ISrsBufferReader
 public:
 	ISrsBufferReader();
 	virtual ~ISrsBufferReader();
+// for protocol/amf0/msg-codec
 public:
     virtual int read(const void* buf, size_t size, ssize_t* nread) = 0;
 };
diff --git a/trunk/src/main/srs_main_bandcheck.cpp b/trunk/src/main/srs_main_bandcheck.cpp
index b5a865066..4d5665219 100644
--- a/trunk/src/main/srs_main_bandcheck.cpp
+++ b/trunk/src/main/srs_main_bandcheck.cpp
@@ -34,6 +34,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_protocol_amf0.hpp>
 #include <srs_core_autofree.hpp>
 #include <srs_kernel_stream.hpp>
+#include <srs_core_socket.hpp>
 
 #include <st.h>
 
@@ -57,6 +58,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define SRS_BW_CHECK_PLAYING            "onSrsBandCheckPlaying"
 #define SRS_BW_CHECK_PUBLISHING         "onSrsBandCheckPublishing"
 
+class ISrsProtocolReaderWriter;
+
 /**
 *  @brief class of Linux version band check client
 *  check play and publish speed.
@@ -64,7 +67,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 class SrsBandCheckClient : public SrsRtmpClient
 {
 public:
-    SrsBandCheckClient(st_netfd_t _stfd);
+    SrsBandCheckClient(ISrsProtocolReaderWriter* io);
     ~SrsBandCheckClient();
 
 public:
@@ -144,8 +147,9 @@ public:
 
 private:
     int connect_server();
-
 private:
+	st_netfd_t stfd;
+	ISrsProtocolReaderWriter* skt;
     SrsBandCheckClient* bandCheck_Client;
     std::string server_address;
     int server_port;
@@ -234,8 +238,8 @@ int main(int argc ,char* argv[])
     return 0;
 }
 
-SrsBandCheckClient::SrsBandCheckClient(st_netfd_t _stfd)
-    : SrsRtmpClient(_stfd)
+SrsBandCheckClient::SrsBandCheckClient(ISrsProtocolReaderWriter* io)
+    : SrsRtmpClient(io)
 {
 }
 
@@ -475,29 +479,17 @@ int SrsBandCheckClient::send_pub_data()
 int SrsBandCheckClient::expect_stop_pub()
 {
     int ret = ERROR_SUCCESS;
-
-    while (true) {
-        if ((ret = st_netfd_poll(stfd, POLLIN, 1000)) == ERROR_SUCCESS) {
-            SrsCommonMessage* msg = 0;
-            if ((ret = recv_message(&msg)) != ERROR_SUCCESS)
-            {
-                srs_error("recv message failed while expect stop pub. ret=%d", ret);
-                return ret;
-            }
-
-            if ((ret = msg->decode_packet(protocol)) != ERROR_SUCCESS) {
-                srs_error("decode packet error while expect stop pub. ret=%d", ret);
-                return ret;
-            }
-
-            SrsBandwidthPacket* pkt = dynamic_cast<SrsBandwidthPacket*>(msg->get_packet());
-            if (pkt && pkt->command_name == SRS_BW_CHECK_STOP_PUBLISH) {
-
-                return ret;
-            }
-        } else {
-            break;
-        }
+    
+    this->set_recv_timeout(1000 * 1000);
+    this->set_send_timeout(1000 * 1000);
+    
+	SrsCommonMessage* msg;
+	SrsBandwidthPacket* pkt;
+    if ((ret = srs_rtmp_expect_message<SrsBandwidthPacket>(this->protocol, &msg, &pkt)) != ERROR_SUCCESS) {
+        return ret;
+    }
+    if (pkt->command_name == SRS_BW_CHECK_STOP_PUBLISH) {
+        return ret;
     }
 
     return ret;
@@ -638,15 +630,17 @@ int SrsBandCheckClient::send_final()
 }
 
 SrsBandCheck::SrsBandCheck()
-    : bandCheck_Client(0)
 {
+	skt = NULL;
+	bandCheck_Client = NULL;
+	stfd = NULL;
 }
 
 SrsBandCheck::~SrsBandCheck()
 {
-    if (bandCheck_Client) {
-        srs_freep(bandCheck_Client);
-    }
+	srs_freep(bandCheck_Client);
+	srs_freep(skt);
+	srs_close_stfd(stfd);
 }
 
 int SrsBandCheck::check(const std::string &app, const std::string &tcUrl)
@@ -698,14 +692,15 @@ int SrsBandCheck::connect_server()
         return ret;
     }
 
-    st_netfd_t stfd = st_netfd_open_socket(sock);
+    stfd = st_netfd_open_socket(sock);
     if(stfd == NULL){
         ret = ERROR_ST_OPEN_SOCKET;
         srs_error("st_netfd_open_socket failed. ret=%d", ret);
         return ret;
     }
 
-    bandCheck_Client = new SrsBandCheckClient(stfd);
+	skt = new SrsSocket(stfd);
+    bandCheck_Client = new SrsBandCheckClient(skt);
 
     // connect to server.
     std::string ip = srs_dns_resolve(server_address);
@@ -763,7 +758,7 @@ void print_help(char** argv)
         "  -h, --help                display this help and exit \n"
         "\n"
 		"For example:\n"
-		"	%s -i 192.168.1.248 -p 1935 -v bandcheck.srs.com -k 35c9b402c12a7246868752e2878f7e0e"
+		"	%s -i 127.0.0.1 -p 1935 -v bandcheck.srs.com -k 35c9b402c12a7246868752e2878f7e0e"
         "\n\n"
         "Exit status:\n"
         "0      if OK,\n"
diff --git a/trunk/src/protocol/srs_protocol_io.cpp b/trunk/src/protocol/srs_protocol_io.cpp
new file mode 100644
index 000000000..5ddb8854d
--- /dev/null
+++ b/trunk/src/protocol/srs_protocol_io.cpp
@@ -0,0 +1,48 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2013-2014 winlin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#include <srs_protocol_io.hpp>
+
+ISrsProtocolReader::ISrsProtocolReader()
+{
+}
+
+ISrsProtocolReader::~ISrsProtocolReader()
+{
+}
+
+ISrsProtocolWriter::ISrsProtocolWriter()
+{
+}
+
+ISrsProtocolWriter::~ISrsProtocolWriter()
+{
+}
+
+ISrsProtocolReaderWriter::ISrsProtocolReaderWriter()
+{
+}
+
+ISrsProtocolReaderWriter::~ISrsProtocolReaderWriter()
+{
+}
diff --git a/trunk/src/protocol/srs_protocol_io.hpp b/trunk/src/protocol/srs_protocol_io.hpp
new file mode 100644
index 000000000..48a4e5ea4
--- /dev/null
+++ b/trunk/src/protocol/srs_protocol_io.hpp
@@ -0,0 +1,87 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2013-2014 winlin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#ifndef SRS_PROTOCOL_IO_HPP
+#define SRS_PROTOCOL_IO_HPP
+
+/*
+#include <srs_protocol_io.hpp>
+*/
+
+#include <srs_core.hpp>
+
+#include <sys/uio.h>
+
+#include <srs_kernel_buffer.hpp>
+
+/**
+* the reader for the protocol to read from whatever channel.
+*/
+class ISrsProtocolReader : public ISrsBufferReader
+{
+public:
+	ISrsProtocolReader();
+	virtual ~ISrsProtocolReader();
+// for protocol
+public:
+	virtual void set_recv_timeout(int64_t timeout_us) = 0;
+	virtual int64_t get_recv_timeout() = 0;
+	virtual int64_t get_recv_bytes() = 0;
+	virtual int get_recv_kbps() = 0;
+};
+
+/**
+* the writer for the protocol to write to whatever channel.
+*/
+class ISrsProtocolWriter
+{
+public:
+	ISrsProtocolWriter();
+	virtual ~ISrsProtocolWriter();
+// for protocol
+public:
+	virtual void set_send_timeout(int64_t timeout_us) = 0;
+	virtual int64_t get_send_timeout() = 0;
+	virtual int64_t get_send_bytes() = 0;
+	virtual int get_send_kbps() = 0;
+    virtual int writev(const iovec *iov, int iov_size, ssize_t* nwrite) = 0;
+};
+
+class ISrsProtocolReaderWriter : public ISrsProtocolReader, public ISrsProtocolWriter
+{
+public:
+	ISrsProtocolReaderWriter();
+	virtual ~ISrsProtocolReaderWriter();
+// for protocol
+public:
+	/**
+	* whether the specified timeout_us is never timeout.
+	*/
+	virtual bool is_never_timeout(int64_t timeout_us) = 0;
+// for handshake.
+public:
+    virtual int read_fully(const void* buf, size_t size, ssize_t* nread) = 0;
+    virtual int write(const void* buf, size_t size, ssize_t* nwrite) = 0;
+};
+
+#endif
diff --git a/trunk/src/srs/srs.upp b/trunk/src/srs/srs.upp
index 48bbd433b..126a5a7ad 100755
--- a/trunk/src/srs/srs.upp
+++ b/trunk/src/srs/srs.upp
@@ -27,6 +27,8 @@ file
     protocol readonly separator,
     ..\protocol\srs_protocol_amf0.hpp,
     ..\protocol\srs_protocol_amf0.cpp,
+    ..\protocol\srs_protocol_io.hpp,
+    ..\protocol\srs_protocol_io.cpp,
     app readonly separator,
     ..\app\srs_core_bandwidth.hpp,
     ..\app\srs_core_bandwidth.cpp,