diff --git a/trunk/src/core/srs_core_client.cpp b/trunk/src/core/srs_core_client.cpp
index 792e96d3b..f18fb23e9 100755
--- a/trunk/src/core/srs_core_client.cpp
+++ b/trunk/src/core/srs_core_client.cpp
@@ -60,29 +60,32 @@ int SrsClient::do_cycle()
 	int ret = ERROR_SUCCESS;
 	
 	if ((ret = get_peer_ip()) != ERROR_SUCCESS) {
-		srs_warn("get peer ip failed. ret=%d", ret);
+		srs_error("get peer ip failed. ret=%d", ret);
 		return ret;
 	}
 	srs_verbose("get peer ip success. ip=%s", ip);
 	
 	if ((ret = rtmp->handshake()) != ERROR_SUCCESS) {
-		srs_warn("rtmp handshake failed. ret=%d", ret);
+		srs_error("rtmp handshake failed. ret=%d", ret);
 		return ret;
 	}
 	srs_verbose("rtmp handshake success");
 	
 	if ((ret = rtmp->connect_app(req)) != ERROR_SUCCESS) {
-		srs_warn("rtmp connect vhost/app failed. ret=%d", ret);
+		srs_error("rtmp connect vhost/app failed. ret=%d", ret);
 		return ret;
 	}
-	srs_info("rtmp connect success. tcUrl=%s, pageUrl=%s, swfUrl=%s", 
-		req->tcUrl.c_str(), req->pageUrl.c_str(), req->swfUrl.c_str());
-		
-	srs_trace("rtmp connect success. "
+	srs_trace("rtmp connect app success. "
 		"tcUrl=%s, pageUrl=%s, swfUrl=%s, schema=%s, vhost=%s, port=%s, app=%s", 
 		req->tcUrl.c_str(), req->pageUrl.c_str(), req->swfUrl.c_str(), 
 		req->schema.c_str(), req->vhost.c_str(), req->port.c_str(),
 		req->app.c_str());
+		
+	if ((ret = rtmp->set_window_ack_size(2.5 * 1000 * 1000)) != ERROR_SUCCESS) {
+		srs_error("set window acknowledgement size failed. ret=%d", ret);
+		return ret;
+	}
+	srs_verbose("set window acknowledgement size success");
 	
 	return ret;
 }
diff --git a/trunk/src/core/srs_core_error.hpp b/trunk/src/core/srs_core_error.hpp
index 1fb0dd225..a0d7a470d 100755
--- a/trunk/src/core/srs_core_error.hpp
+++ b/trunk/src/core/srs_core_error.hpp
@@ -55,6 +55,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define ERROR_RTMP_AMF0_DECODE			303
 #define ERROR_RTMP_AMF0_INVALID			304
 #define ERROR_RTMP_REQ_CONNECT			305
+#define ERROR_RTMP_REQ_TCURL			306
+#define ERROR_RTMP_MESSAGE_DECODE		307
 
 #define ERROR_SYSTEM_STREAM_INIT		400
 
diff --git a/trunk/src/core/srs_core_protocol.cpp b/trunk/src/core/srs_core_protocol.cpp
index 5a79e4049..139c7a520 100755
--- a/trunk/src/core/srs_core_protocol.cpp
+++ b/trunk/src/core/srs_core_protocol.cpp
@@ -30,6 +30,9 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_core_buffer.hpp>
 #include <srs_core_stream.hpp>
 
+/****************************************************************************
+*****************************************************************************
+****************************************************************************/
 /**
 5. Protocol Control Messages
 RTMP reserves message type IDs 1-7 for protocol control messages.
@@ -124,6 +127,9 @@ messages.
 */
 #define RTMP_MSG_AggregateMessage 			22 // 0x16
 
+/****************************************************************************
+*****************************************************************************
+****************************************************************************/
 /**
 * 6.1.2. Chunk Message Header
 * There are four different formats for the chunk message header,
@@ -164,6 +170,9 @@ messages.
 // the same as the timestamp of Type 0 chunk.
 #define RTMP_FMT_TYPE3 						3
 
+/****************************************************************************
+*****************************************************************************
+****************************************************************************/
 /**
 * 6. Chunking
 * The chunk size is configurable. It can be set using a control
@@ -189,11 +198,58 @@ messages.
 */
 #define RTMP_EXTENDED_TIMESTAMP 			0xFFFFFF
 
+/****************************************************************************
+*****************************************************************************
+****************************************************************************/
 /**
 * amf0 command message, command name: "connect"
 */
 #define RTMP_AMF0_COMMAND_CONNECT			"connect"
 
+/****************************************************************************
+*****************************************************************************
+****************************************************************************/
+/**
+* the chunk stream id used for some under-layer message,
+* for example, the PC(protocol control) message.
+*/
+#define RTMP_CID_ProtocolControl 0x02
+/**
+* the AMF0/AMF3 command message, invoke method and return the result, over NetConnection.
+* generally use 0x03.
+*/
+#define RTMP_CID_OverConnection 0x03
+/**
+* the AMF0/AMF3 command message, invoke method and return the result, over NetConnection, 
+* the midst state(we guess).
+* rarely used, e.g. onStatus(NetStream.Play.Reset).
+*/
+#define RTMP_CID_OverConnection2 0x04
+/**
+* the stream message(amf0/amf3), over NetStream.
+* generally use 0x05.
+*/
+#define RTMP_CID_OverStream 0x05
+/**
+* the stream message(amf0/amf3), over NetStream, the midst state(we guess).
+* rarely used, e.g. play("mp4:mystram.f4v")
+*/
+#define RTMP_CID_OverStream2 0x08
+/**
+* the stream message(video), over NetStream
+* generally use 0x06.
+*/
+#define RTMP_CID_Video 0x06
+/**
+* the stream message(audio), over NetStream.
+* generally use 0x07.
+*/
+#define RTMP_CID_Audio 0x07
+
+/****************************************************************************
+*****************************************************************************
+****************************************************************************/
+
 SrsProtocol::SrsProtocol(st_netfd_t client_stfd)
 {
 	stfd = client_stfd;
@@ -263,6 +319,118 @@ int SrsProtocol::recv_message(SrsMessage** pmsg)
 	return ret;
 }
 
+int SrsProtocol::send_message(SrsMessage* msg)
+{
+	int ret = ERROR_SUCCESS;
+	
+	if ((ret = msg->encode_packet()) != ERROR_SUCCESS) {
+		srs_error("encode packet to message payload failed. ret=%d", ret);
+		return ret;
+	}
+	srs_info("encode packet to message payload success");
+
+	// p set to current write position,
+	// it's ok when payload is NULL and size is 0.
+	char* p = (char*)msg->payload;
+	
+	// always write the header event payload is empty.
+	do {
+		// generate the header.
+		char* pheader = NULL;
+		int header_size = 0;
+		
+		if (p == (char*)msg->payload) {
+			// write new chunk stream header, fmt is 0
+			pheader = out_header_fmt0;
+			*pheader++ = 0x00 | (msg->get_perfer_cid() & 0x3F);
+			
+		    // chunk message header, 11 bytes
+		    // timestamp, 3bytes, big-endian
+			if (msg->header.timestamp >= RTMP_EXTENDED_TIMESTAMP) {
+		        *pheader++ = 0xFF;
+		        *pheader++ = 0xFF;
+		        *pheader++ = 0xFF;
+			} else {
+		        pp = (char*)&msg->header.timestamp; 
+		        *pheader++ = pp[2];
+		        *pheader++ = pp[1];
+		        *pheader++ = pp[0];
+			}
+			
+		    // message_length, 3bytes, big-endian
+		    pp = (char*)&msg->header.payload_length;
+		    *pheader++ = pp[2];
+		    *pheader++ = pp[1];
+		    *pheader++ = pp[0];
+		    
+		    // message_type, 1bytes
+		    *pheader++ = msg->header.message_type;
+		    
+		    // message_length, 3bytes, little-endian
+		    pp = (char*)&msg->header.stream_id;
+		    *pheader++ = pp[0];
+		    *pheader++ = pp[1];
+		    *pheader++ = pp[2];
+		    *pheader++ = pp[3];
+		    
+		    // chunk extended timestamp header, 0 or 4 bytes, big-endian
+		    if(msg->header.timestamp >= RTMP_EXTENDED_TIMESTAMP){
+		        pp = (char*)&msg->header.timestamp; 
+		        *pheader++ = pp[3];
+		        *pheader++ = pp[2];
+		        *pheader++ = pp[1];
+		        *pheader++ = pp[0];
+		    }
+			
+			header_size = pheader - out_header_fmt0;
+			pheader = out_header_fmt0;
+		} else {
+			// write no message header chunk stream, fmt is 3
+			pheader = out_header_fmt3;
+			*pheader++ = 0xC0 | (msg->get_perfer_cid() & 0x3F);
+		    
+		    // chunk extended timestamp header, 0 or 4 bytes, big-endian
+		    if(msg->header.timestamp >= RTMP_EXTENDED_TIMESTAMP){
+		        pp = (char*)&msg->header.timestamp; 
+		        *pheader++ = pp[3];
+		        *pheader++ = pp[2];
+		        *pheader++ = pp[1];
+		        *pheader++ = pp[0];
+		    }
+			
+			header_size = pheader - out_header_fmt3;
+			pheader = out_header_fmt3;
+		}
+		
+		// sendout header and payload by writev.
+		// decrease the sys invoke count to get higher performance.
+		int payload_size = msg->size - ((char*)msg->payload - p);
+		if (payload_size > out_chunk_size) {
+			payload_size = out_chunk_size;
+		}
+		
+		// send by writev
+		iovec iov[2];
+		iov[0].iov_base = pheader;
+		iov[0].iov_len = header_size;
+		iov[1].iov_base = p;
+		iov[1].iov_len = payload_size;
+		
+		ssize_t nwrite;
+		if ((ret = skt->writev(iov, 2, &nwrite)) != ERROR_SUCCESS) {
+			srs_error("send with writev failed. ret=%d", ret);
+			return ret;
+		}
+		
+		// consume sendout bytes when not empty packet.
+		if (msg->payload && msg->size > 0) {
+			p += payload_size;
+		}
+	} while (p < (char*)msg->payload + msg->size);
+	
+	return ret;
+}
+
 int SrsProtocol::recv_interlaced_message(SrsMessage** pmsg)
 {
 	int ret = ERROR_SUCCESS;
@@ -325,7 +493,7 @@ int SrsProtocol::recv_interlaced_message(SrsMessage** pmsg)
 	return ret;
 }
 
-int SrsProtocol::read_basic_header(char& fmt, int& cid, int& size)
+int SrsProtocol::read_basic_header(char& fmt, int& cid, int& bh_size)
 {
 	int ret = ERROR_SUCCESS;
 	
@@ -339,10 +507,10 @@ int SrsProtocol::read_basic_header(char& fmt, int& cid, int& size)
 	
     fmt = (*p >> 6) & 0x03;
     cid = *p & 0x3f;
-    size = 1;
+    bh_size = 1;
     
     if (cid > 1) {
-		srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", size, fmt, cid);
+		srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", bh_size, fmt, cid);
         return ret;
     }
 
@@ -355,8 +523,8 @@ int SrsProtocol::read_basic_header(char& fmt, int& cid, int& size)
 		
 		cid = 64;
 		cid += *(++p);
-    	size = 2;
-		srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", size, fmt, cid);
+    	bh_size = 2;
+		srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", bh_size, fmt, cid);
 	} else if (cid == 1) {
 		required_size = 3;
 		if ((ret = buffer->ensure_buffer_bytes(skt, 3)) != ERROR_SUCCESS) {
@@ -367,8 +535,8 @@ int SrsProtocol::read_basic_header(char& fmt, int& cid, int& size)
 		cid = 64;
 		cid += *(++p);
 		cid += *(++p) * 256;
-    	size = 3;
-		srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", size, fmt, cid);
+    	bh_size = 3;
+		srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", bh_size, fmt, cid);
 	} else {
 		srs_error("invalid path, impossible basic header.");
 		srs_assert(false);
@@ -620,7 +788,7 @@ SrsMessage::SrsMessage()
 	size = 0;
 	stream = NULL;
 	payload = NULL;
-	decoded_payload = NULL;
+	packet = NULL;
 }
 
 SrsMessage::~SrsMessage()
@@ -630,9 +798,9 @@ SrsMessage::~SrsMessage()
 		payload = NULL;
 	}
 	
-	if (decoded_payload) {
-		delete decoded_payload;
-		decoded_payload = NULL;
+	if (packet) {
+		delete packet;
+		packet = NULL;
 	}
 	
 	if (stream) {
@@ -641,16 +809,6 @@ SrsMessage::~SrsMessage()
 	}
 }
 
-SrsPacket* SrsMessage::get_packet()
-{
-	if (!decoded_payload) {
-		srs_error("the payload is raw/undecoded, invoke decode_packet to decode it.");
-	}
-	srs_assert(decoded_payload != NULL);
-	
-	return decoded_payload;
-}
-
 int SrsMessage::decode_packet()
 {
 	int ret = ERROR_SUCCESS;
@@ -684,19 +842,64 @@ int SrsMessage::decode_packet()
 		stream->reset();
 		if (command == RTMP_AMF0_COMMAND_CONNECT) {
 			srs_info("decode the AMF0 command(connect vhost/app message).");
-			decoded_payload = new SrsConnectAppPacket();
-			return decoded_payload->decode(stream);
+			packet = new SrsConnectAppPacket();
+			return packet->decode(stream);
 		}
 		
 		// default packet to drop message.
 		srs_trace("drop the AMF0 command message, command_name=%s", command.c_str());
-		decoded_payload = new SrsPacket();
+		packet = new SrsPacket();
 		return ret;
 	}
 	
 	// default packet to drop message.
 	srs_trace("drop the unknown message, type=%d", header.message_type);
-	decoded_payload = new SrsPacket();
+	packet = new SrsPacket();
+	
+	return ret;
+}
+
+SrsPacket* SrsMessage::get_packet()
+{
+	if (!packet) {
+		srs_error("the payload is raw/undecoded, invoke decode_packet to decode it.");
+	}
+	srs_assert(packet != NULL);
+	
+	return packet;
+}
+
+int SrsMessage::get_perfer_cid()
+{
+	if (!packet) {
+		return RTMP_CID_ProtocolControl;
+	}
+	
+	// we donot use the complex basic header,
+	// ensure the basic header is 1bytes.
+	if (packet->get_perfer_cid() < 2) {
+		return packet->get_perfer_cid();
+	}
+	
+	return packet->get_perfer_cid();
+}
+
+void SrsMessage::set_packet(SrsPacket* pkt)
+{
+	if (packet) {
+		delete packet;
+	}
+	packet = pkt;
+}
+
+int SrsMessage::encode_packet()
+{
+	int ret = ERROR_SUCCESS;
+	
+	if (packet == NULL) {
+		srs_warn("packet is empty, send out empty message.");
+		return ret;
+	}
 	
 	return ret;
 }
@@ -715,6 +918,11 @@ int SrsPacket::decode(SrsStream* /*stream*/)
 	return ret;
 }
 
+int SrsPacket::get_perfer_cid()
+{
+	return 0;
+}
+
 SrsConnectAppPacket::SrsConnectAppPacket()
 {
 	command_name = RTMP_AMF0_COMMAND_CONNECT;
@@ -771,3 +979,37 @@ int SrsConnectAppPacket::decode(SrsStream* stream)
 	return ret;
 }
 
+SrsSetWindowAckSizePacket::SrsSetWindowAckSizePacket()
+{
+	ackowledgement_window_size = 0;
+}
+
+SrsSetWindowAckSizePacket::~SrsSetWindowAckSizePacket()
+{
+}
+
+int SrsSetWindowAckSizePacket::decode(SrsStream* stream)
+{
+	int ret = ERROR_SUCCESS;
+	
+	if ((ret = super::decode(stream)) != ERROR_SUCCESS) {
+		return ret;
+	}
+	
+	if (!stream->require(4)) {
+		ret = ERROR_RTMP_MESSAGE_DECODE;
+		srs_error("set window ack size failed. ret=%d", ret);
+		return ret;
+	}
+	
+	ackowledgement_window_size = stream->read_4bytes();
+	srs_info("decode window ack size success. ack_size=%d", ackowledgement_window_size);
+	
+	return ret;
+}
+
+int SrsSetWindowAckSizePacket::get_perfer_cid()
+{
+	return RTMP_CID_ProtocolControl;
+}
+
diff --git a/trunk/src/core/srs_core_protocol.hpp b/trunk/src/core/srs_core_protocol.hpp
index e01af95f6..e6c3a4d61 100755
--- a/trunk/src/core/srs_core_protocol.hpp
+++ b/trunk/src/core/srs_core_protocol.hpp
@@ -46,6 +46,22 @@ class SrsMessage;
 class SrsChunkStream;
 class SrsAmf0Object;
 
+/**
+* max rtmp header size:
+* 	1bytes basic header,
+* 	11bytes message header,
+* 	4bytes timestamp header,
+* that is, 1+11+4=16bytes.
+*/
+#define RTMP_MAX_FMT0_HEADER_SIZE 16
+/**
+* max rtmp header size:
+* 	1bytes basic header,
+* 	4bytes timestamp header,
+* that is, 1+4=5bytes.
+*/
+#define RTMP_MAX_FMT3_HEADER_SIZE 5
+
 /**
 * the protocol provides the rtmp-message-protocol services,
 * to recv RTMP message from RTMP chunk stream,
@@ -53,12 +69,20 @@ class SrsAmf0Object;
 */
 class SrsProtocol
 {
+// peer in/out
+private:
+	st_netfd_t stfd;
+	SrsSocket* skt;
+	char* pp;
+// peer in
 private:
 	std::map<int, SrsChunkStream*> chunk_streams;
-	st_netfd_t stfd;
 	SrsBuffer* buffer;
-	SrsSocket* skt;
 	int32_t in_chunk_size;
+// peer out
+private:
+	char out_header_fmt0[RTMP_MAX_FMT0_HEADER_SIZE];
+	char out_header_fmt3[RTMP_MAX_FMT3_HEADER_SIZE];
 	int32_t out_chunk_size;
 public:
 	SrsProtocol(st_netfd_t client_stfd);
@@ -72,10 +96,38 @@ public:
 	* @remark, only when success, user can use and must free the pmsg.
 	*/
 	virtual int recv_message(SrsMessage** pmsg);
+	/**
+	* send out message with encoded payload to peer.
+	* use the message encode method to encode to payload,
+	* then sendout over socket.
+	* @msg this method will free it whatever return value.
+	*/
+	virtual int send_message(SrsMessage* msg);
 private:
+	/**
+	* try to recv interlaced message from peer,
+	* return error if error occur and nerver set the pmsg,
+	* return success and pmsg set to NULL if no entire message got,
+	* return success and pmsg set to entire message if got one.
+	*/
 	virtual int recv_interlaced_message(SrsMessage** pmsg);
-	virtual int read_basic_header(char& fmt, int& cid, int& size);
+	/**
+	* read the chunk basic header(fmt, cid) from chunk stream.
+	* user can discovery a SrsChunkStream by cid.
+	* @bh_size return the chunk basic header size, to remove the used bytes when finished.
+	*/
+	virtual int read_basic_header(char& fmt, int& cid, int& bh_size);
+	/**
+	* read the chunk message header(timestamp, payload_length, message_type, stream_id) 
+	* from chunk stream and save to SrsChunkStream.
+	* @mh_size return the chunk message header size, to remove the used bytes when finished.
+	*/
 	virtual int read_message_header(SrsChunkStream* chunk, char fmt, int bh_size, int& mh_size);
+	/**
+	* read the chunk payload, remove the used bytes in buffer,
+	* if got entire message, set the pmsg.
+	* @payload_size read size in this roundtrip, generally a chunk size or left message size.
+	*/
 	virtual int read_message_payload(SrsChunkStream* chunk, int bh_size, int mh_size, int& payload_size, SrsMessage** pmsg);
 };
 
@@ -164,19 +216,35 @@ public:
 // decoded message payload.
 private:
 	SrsStream* stream;
-	SrsPacket* decoded_payload;
-public:
-	/**
-	* get the decoded packet,
-	* not all packets need to decode, for video/audio packet,
-	* passthrough to peer are ok.
-	* @remark, user must invoke decode_packet first.
-	*/
-	virtual SrsPacket* get_packet();
-	virtual int decode_packet();
+	SrsPacket* packet;
 public:
 	SrsMessage();
 	virtual ~SrsMessage();
+public:
+	/**
+	* decode packet from message payload.
+	*/
+	virtual int decode_packet();
+	/**
+	* get the decoded packet which decoded by decode_packet().
+	* @remark, user never free the pkt, the message will auto free it.
+	*/
+	virtual SrsPacket* get_packet();
+public:
+	/**
+	* get the perfered cid(chunk stream id) which sendout over.
+	*/
+	virtual int get_perfer_cid();
+	/**
+	* set the encoded packet to encode_packet() to payload.
+	* @remark, user never free the pkt, the message will auto free it.
+	*/
+	virtual void set_packet(SrsPacket* pkt);
+	/**
+	* encode the packet to message payload bytes.
+	* @remark there exists empty packet, so maybe the payload is NULL.
+	*/
+	virtual int encode_packet();
 };
 
 /**
@@ -189,8 +257,15 @@ public:
 	virtual ~SrsPacket();
 public:
 	virtual int decode(SrsStream* stream);
+public:
+	virtual int get_perfer_cid();
 };
 
+/**
+* 4.1.1. connect
+* The client sends the connect command to the server to request
+* connection to a server application instance.
+*/
 class SrsConnectAppPacket : public SrsPacket
 {
 private:
@@ -206,6 +281,26 @@ public:
 	virtual int decode(SrsStream* stream);
 };
 
+/**
+* 5.5. Window Acknowledgement Size (5)
+* The client or the server sends this message to inform the peer which
+* window size to use when sending acknowledgment.
+*/
+class SrsSetWindowAckSizePacket : public SrsPacket
+{
+private:
+	typedef SrsPacket super;
+public:
+	int32_t ackowledgement_window_size;
+public:
+	SrsSetWindowAckSizePacket();
+	virtual ~SrsSetWindowAckSizePacket();
+public:
+	virtual int decode(SrsStream* stream);
+public:
+	virtual int get_perfer_cid();
+};
+
 /**
 * expect a specified message, drop others util got specified one.
 * @pmsg, user must free it. NULL if not success.
diff --git a/trunk/src/core/srs_core_rtmp.cpp b/trunk/src/core/srs_core_rtmp.cpp
index 87b8959fa..f9388696c 100755
--- a/trunk/src/core/srs_core_rtmp.cpp
+++ b/trunk/src/core/srs_core_rtmp.cpp
@@ -30,6 +30,47 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <srs_core_auto_free.hpp>
 #include <srs_core_amf0.hpp>
 
+int SrsRequest::discovery_app()
+{
+	int ret = ERROR_SUCCESS;
+	
+	size_t pos = std::string::npos;
+	std::string url = tcUrl;
+	
+	if ((pos = url.find("://")) != std::string::npos) {
+		schema = url.substr(0, pos);
+		url = url.substr(schema.length() + 3);
+		srs_verbose("discovery schema=%s", schema.c_str());
+	}
+	
+	if ((pos = url.find("/")) != std::string::npos) {
+		vhost = url.substr(0, pos);
+		url = url.substr(vhost.length() + 1);
+		srs_verbose("discovery vhost=%s", vhost.c_str());
+	}
+
+	port = "1935";
+	if ((pos = vhost.find(":")) != std::string::npos) {
+		port = vhost.substr(pos + 1);
+		vhost = vhost.substr(0, pos);
+		srs_verbose("discovery vhost=%s, port=%s", vhost.c_str(), port.c_str());
+	}
+	
+	app = url;
+	srs_info("discovery app success. schema=%s, vhost=%s, port=%s, app=%s",
+		schema.c_str(), vhost.c_str(), port.c_str(), app.c_str());
+	
+	if (schema.empty() || vhost.empty() || port.empty() || app.empty()) {
+		ret = ERROR_RTMP_REQ_TCURL;
+		srs_error("discovery tcUrl failed. "
+			"tcUrl=%s, schema=%s, vhost=%s, port=%s, app=%s, ret=%d",
+			tcUrl.c_str(), schema.c_str(), vhost.c_str(), port.c_str(), app.c_str(), ret);
+		return ret;
+	}
+	
+	return ret;
+}
+
 SrsRtmp::SrsRtmp(st_netfd_t client_stfd)
 {
 	protocol = new SrsProtocol(client_stfd);
@@ -119,6 +160,26 @@ int SrsRtmp::connect_app(SrsRequest* req)
 	if ((prop = pkt->command_object->ensure_property_string("swfUrl")) != NULL) {
 		req->swfUrl = srs_amf0_convert<SrsAmf0String>(prop)->value;
 	}
+	srs_info("get connect app message params success.");
+	
+	return req->discovery_app();
+}
+
+int SrsRtmp::set_window_ack_size(int ack_size)
+{
+	int ret = ERROR_SUCCESS;
+	
+	SrsMessage* msg = new SrsMessage();
+	SrsSetWindowAckSizePacket* pkt = new SrsSetWindowAckSizePacket();
+	
+	pkt->ackowledgement_window_size = ack_size;
+	msg->set_packet(pkt);
+	
+	if ((ret = protocol->send_message(msg)) != ERROR_SUCCESS) {
+		srs_error("send ack size message failed. ret=%d", ret);
+		return ret;
+	}
+	srs_info("send ack size message success. ack_size=%d", ack_size);
 	
 	return ret;
 }
diff --git a/trunk/src/core/srs_core_rtmp.hpp b/trunk/src/core/srs_core_rtmp.hpp
index e12b14281..bd9a2472c 100755
--- a/trunk/src/core/srs_core_rtmp.hpp
+++ b/trunk/src/core/srs_core_rtmp.hpp
@@ -50,6 +50,11 @@ struct SrsRequest
 	std::string port;
 	std::string app;
 	std::string stream;
+	
+	/**
+	* disconvery vhost/app from tcUrl.
+	*/
+	virtual int discovery_app();
 };
 
 /**
@@ -68,6 +73,7 @@ public:
 public:
 	virtual int handshake();
 	virtual int connect_app(SrsRequest* req);
+	virtual int set_window_ack_size(int ack_size);
 };
 
 #endif
\ No newline at end of file
diff --git a/trunk/src/core/srs_core_socket.cpp b/trunk/src/core/srs_core_socket.cpp
index 1994a8203..210056b21 100755
--- a/trunk/src/core/srs_core_socket.cpp
+++ b/trunk/src/core/srs_core_socket.cpp
@@ -85,3 +85,16 @@ int SrsSocket::write(const void* buf, size_t size, ssize_t* nwrite)
     return ret;
 }
 
+int SrsSocket::writev(const iovec *iov, int iov_size, ssize_t* nwrite)
+{
+    int ret = ERROR_SUCCESS;
+    
+    *nwrite = st_writev(stfd, iov, iov_size, ST_UTIME_NO_TIMEOUT);
+    
+    if (*nwrite <= 0) {
+        ret = ERROR_SOCKET_WRITE;
+    }
+    
+    return ret;
+}
+
diff --git a/trunk/src/core/srs_core_socket.hpp b/trunk/src/core/srs_core_socket.hpp
index 2cc5ebedd..6672db3b9 100755
--- a/trunk/src/core/srs_core_socket.hpp
+++ b/trunk/src/core/srs_core_socket.hpp
@@ -47,6 +47,7 @@ public:
     virtual int read(const void* buf, size_t size, ssize_t* nread);
     virtual int read_fully(const void* buf, size_t size, ssize_t* nread);
     virtual int write(const void* buf, size_t size, ssize_t* nwrite);
+    virtual int writev(const iovec *iov, int iov_size, ssize_t* nwrite);
 };
 
 #endif
\ No newline at end of file
diff --git a/trunk/src/core/srs_core_stream.cpp b/trunk/src/core/srs_core_stream.cpp
index 06bb9f8bd..3b5e1d6af 100755
--- a/trunk/src/core/srs_core_stream.cpp
+++ b/trunk/src/core/srs_core_stream.cpp
@@ -97,6 +97,20 @@ int16_t SrsStream::read_2bytes()
 	return value;
 }
 
+int32_t SrsStream::read_4bytes()
+{
+	srs_assert(require(4));
+	
+	int32_t value;
+	pp = (char*)&value;
+	pp[3] = *p++;
+	pp[2] = *p++;
+	pp[1] = *p++;
+	pp[0] = *p++;
+	
+	return value;
+}
+
 int64_t SrsStream::read_8bytes()
 {
 	srs_assert(require(8));
diff --git a/trunk/src/core/srs_core_stream.hpp b/trunk/src/core/srs_core_stream.hpp
index 320118d68..9055492f5 100755
--- a/trunk/src/core/srs_core_stream.hpp
+++ b/trunk/src/core/srs_core_stream.hpp
@@ -80,6 +80,10 @@ public:
 	*/
 	virtual int16_t read_2bytes();
 	/**
+	* get 4bytes int from stream.
+	*/
+	virtual int32_t read_4bytes();
+	/**
 	* get 8bytes int from stream.
 	*/
 	virtual int64_t read_8bytes();