diff --git a/agent.lua b/agent.lua
index 6c1734b6..9f09e6fd 100644
--- a/agent.lua
+++ b/agent.lua
@@ -5,7 +5,7 @@ skynet.dispatch(function(msg,session)
 	if session == 0 then
 		print("client command",msg)
 		local result = skynet.call("SIMPLEDB",msg)
-		skynet.send(client,0,result)
+		skynet.send(client, result)
 	else
 		print("server command",msg)
 		if msg == "CLOSE" then
diff --git a/gate/main.c b/gate/main.c
index 03c7e642..50418ad4 100644
--- a/gate/main.c
+++ b/gate/main.c
@@ -178,7 +178,7 @@ _cb(struct skynet_context * ctx, void * ud, int session, const char * uid, const
 	struct mread_pool * m = g->pool;
 	int connection_id = mread_poll(m,100);	// timeout : 100ms
 	if (connection_id < 0) {
-		skynet_command(ctx, "TIMEOUT", 0, "1");
+		skynet_command(ctx, "TIMEOUT", "1");
 	} else {
 		int id = g->map[connection_id].uid;
 		if (id == 0) {
@@ -209,7 +209,7 @@ _cb(struct skynet_context * ctx, void * ud, int session, const char * uid, const
 		_forward(ctx, g, id, data, *plen);
 		mread_yield(m);
 _break:
-		skynet_command(ctx, "TIMEOUT",0,"0");
+		skynet_command(ctx, "TIMEOUT", "0");
 	}
 }
 
@@ -249,8 +249,8 @@ gate_init(struct gate *g , struct skynet_context * ctx, char * parm) {
 	}
 
 	skynet_callback(ctx,g,_cb);
-	skynet_command(ctx,"REG",0,"gate");
-	skynet_command(ctx,"TIMEOUT",0, "0");
+	skynet_command(ctx,"REG","gate");
+	skynet_command(ctx,"TIMEOUT","0");
 
 	return 0;
 }
diff --git a/globallog.lua b/globallog.lua
index f6379996..b202f4ce 100644
--- a/globallog.lua
+++ b/globallog.lua
@@ -1,7 +1,7 @@
 local skynet = require "skynet"
 
 skynet.dispatch(function(message, session , from)
-	print("[GLOBALLOG]",session, from,message)
+	print("[GLOBALLOG]", from,message)
 end)
 
 skynet.register "LOG"
\ No newline at end of file
diff --git a/lua-skynet.c b/lua-skynet.c
index 404d6d67..968f49d5 100644
--- a/lua-skynet.c
+++ b/lua-skynet.c
@@ -59,24 +59,13 @@ static int
 _command(lua_State *L) {
 	struct skynet_context * context = lua_touserdata(L, lua_upvalueindex(1));
 	const char * cmd = luaL_checkstring(L,1);
-	const char * parm = NULL;
-	int session = 0;
 	const char * result;
-	int top = lua_gettop(L);
-	if (top == 2) {
-		if (lua_type(L,2) == LUA_TNUMBER) {
-			session = lua_tointeger(L,2);
-		} else {
-			parm = luaL_checkstring(L,2);
-		}
-	} else if (top == 3) {
-		session = lua_tointeger(L,2);
-		parm = luaL_checkstring(L,3);
-	} else if (top != 1) {
-		luaL_error(L, "skynet.command support only 3 parms (%d)",top);
+	const char * parm = NULL;
+	if (lua_gettop(L) == 2) {
+		parm = luaL_checkstring(L,2);
 	}
 
-	result = skynet_command(context, cmd, session, parm);
+	result = skynet_command(context, cmd, parm);
 	if (result) {
 		lua_pushstring(L, result);
 		return 1;
@@ -87,7 +76,7 @@ _command(lua_State *L) {
 static int
 _send(lua_State *L) {
 	struct skynet_context * context = lua_touserdata(L, lua_upvalueindex(1));
-	int session = -1;
+	int session = 0;
 	int index = 0;
 	const char * dest = luaL_checkstring(L,1);
 
diff --git a/skynet.h b/skynet.h
index a6bd72ad..9dd4dcbb 100644
--- a/skynet.h
+++ b/skynet.h
@@ -7,7 +7,7 @@
 struct skynet_context;
 
 void skynet_error(struct skynet_context * context, const char *msg, ...);
-const char * skynet_command(struct skynet_context * context, const char * cmd , int session, const char * parm);
+const char * skynet_command(struct skynet_context * context, const char * cmd , const char * parm);
 int skynet_send(struct skynet_context * context, const char * addr , int session, void * msg, size_t sz);
 
 typedef void (*skynet_cb)(struct skynet_context * context, void *ud, int session, const char * addr , const void * msg, size_t sz);
diff --git a/skynet.lua b/skynet.lua
index bdb803c0..8f18bda3 100644
--- a/skynet.lua
+++ b/skynet.lua
@@ -82,13 +82,15 @@ end
 
 function skynet.dispatch(f)
 	c.callback(function(session, address , message)
-		local co = session_id_coroutine[session]
-		if co == nil then
+		if session <= 0 then
+			session = - session
 			co = coroutine.create(f)
 			session_coroutine_id[co] = session
 			session_coroutine_address[co] = address
 			suspend(co, coroutine.resume(co, message, session, address))
 		else
+			local co = session_id_coroutine[session]
+			assert(co, session)
 			session_id_coroutine[session] = nil
 			suspend(co, coroutine.resume(co, message))
 		end
@@ -96,9 +98,9 @@ function skynet.dispatch(f)
 end
 
 function skynet.start(f)
-	c.command("TIMEOUT",0,"0")
+	local session = c.command("TIMEOUT","0")
 	local co = coroutine.create(f)
-	session_id_coroutine[0] = co
+	session_id_coroutine[tonumber(session)] = co
 end
 
 return skynet
diff --git a/skynet_logger.c b/skynet_logger.c
index 0f11b91c..64a655be 100644
--- a/skynet_logger.c
+++ b/skynet_logger.c
@@ -45,7 +45,7 @@ logger_init(struct logger * inst, struct skynet_context *ctx, const char * parm)
 	}
 	if (inst->handle) {
 		skynet_callback(ctx, inst, _logger);
-		skynet_command(ctx, "REG", 0, ".logger");
+		skynet_command(ctx, "REG", ".logger");
 		return 0;
 	}
 	return 1;
diff --git a/skynet_server.c b/skynet_server.c
index a1b4447d..92e814ee 100644
--- a/skynet_server.c
+++ b/skynet_server.c
@@ -197,13 +197,14 @@ skynet_context_message_dispatch(void) {
 }
 
 const char * 
-skynet_command(struct skynet_context * context, const char * cmd , int session, const char * parm) {
+skynet_command(struct skynet_context * context, const char * cmd , const char * parm) {
 	if (strcmp(cmd,"TIMEOUT") == 0) {
 		char * session_ptr = NULL;
 		int ti = strtol(parm, &session_ptr, 10);
-		session = skynet_timeout(context->handle, ti, session);
-		if (session < 0)
+		int session = skynet_context_newsession(context);
+		if (session < 0) 
 			return NULL;
+		skynet_timeout(context->handle, ti, session);
 		sprintf(context->result, "%d", session);
 		return context->result;
 	}
@@ -268,8 +269,10 @@ skynet_command(struct skynet_context * context, const char * cmd , int session,
 
 int
 skynet_send(struct skynet_context * context, const char * addr , int session, void * msg, size_t sz) {
+	int session_id = session;
 	if (session < 0) {
 		session = skynet_context_newsession(context);
+		session_id = - session;
 	}
 	uint32_t des = 0;
 	if (addr[0] == ':') {
@@ -284,7 +287,7 @@ skynet_send(struct skynet_context * context, const char * addr , int session, vo
 	} else {
 		struct skynet_message smsg;
 		smsg.source = context->handle;
-		smsg.session = session;
+		smsg.session = session_id;
 		smsg.data = msg;
 		smsg.sz = sz;
 		skynet_harbor_send(addr, 0, &smsg);
@@ -295,7 +298,7 @@ skynet_send(struct skynet_context * context, const char * addr , int session, vo
 
 	struct skynet_message smsg;
 	smsg.source = context->handle;
-	smsg.session = session;
+	smsg.session = session_id;
 	smsg.data = msg;
 	smsg.sz = sz;
 
@@ -332,7 +335,6 @@ skynet_context_push(uint32_t handle, struct skynet_message *message) {
 	if (ctx == NULL) {
 		return -1;
 	}
-	assert(message->session >= 0);
 	skynet_mq_push(ctx->queue, message);
 	if (__sync_lock_test_and_set(&ctx->in_global_queue,1) == 0) {
 		skynet_globalmq_push(ctx->queue);
diff --git a/skynet_timer.c b/skynet_timer.c
index 3beadbb7..4ab635a2 100644
--- a/skynet_timer.c
+++ b/skynet_timer.c
@@ -174,15 +174,6 @@ timer_create_timer()
 
 int
 skynet_timeout(uint32_t handle, int time, int session) {
-	if (session < 0) {
-		struct skynet_context * ctx = skynet_handle_grab(handle);
-		if (ctx == NULL) {
-			return -1;
-		}
-		session = skynet_context_newsession(ctx);
-		skynet_context_release(ctx);
-	}
-
 	if (time == 0) {
 		struct skynet_message message;
 		message.source = SKYNET_SYSTEM_TIMER;
diff --git a/watchdog.lua b/watchdog.lua
index 937e8aca..12f836dd 100644
--- a/watchdog.lua
+++ b/watchdog.lua
@@ -6,28 +6,28 @@ local agent_all = {}
 function command:open(parm)
 	local fd,addr = string.match(parm,"(%d+) ([^%s]+)")
 	fd = tonumber(fd)
-	skynet.send("LOG", 0, string.format("%d %d %s",self,fd,addr))
+	skynet.send("LOG", string.format("%d %d %s",self,fd,addr))
 	local client = skynet.launch("client",fd)
-	print("client",client)
+	skynet.send("LOG", "client " .. client)
 	local agent = skynet.launch("snlua","agent.lua",client)
 	if agent then
 		agent_all[self] = agent
-		skynet.send("gate",0, "forward ".. self .. " " .. agent)
+		skynet.send("gate", "forward ".. self .. " " .. agent)
 	end
 end
 
 function command:close()
-	skynet.send("LOG",0,string.format("close %d",self))
-	skynet.send(agent_all[self],1,"CLOSE")
+	skynet.send("LOG", string.format("close %d",self))
+	skynet.send(agent_all[self],-1,"CLOSE")
 	agent_all[self] = nil
 end
 
 function command:data(data)
 	local agent = agent_all[self]
 	if agent then
-		skynet.send(agent,0,data)
+		skynet.send(agent, data)
 	else
-		skynet.send("LOG",0,string.format("data %d size=%d",self,#data))
+		skynet.send("LOG", string.format("data %d size=%d",self,#data))
 	end
 end