diff --git a/connection.cpp b/connection.cpp
index 5325bca..c357e43 100644
--- a/connection.cpp
+++ b/connection.cpp
@@ -15,13 +15,18 @@ const int disable_conn_clear=0;//a raw connection is called conn.
 
 conn_manager_t conn_manager;
 
-void server_clear_function(u64_t u64);
+void server_clear_function(u64_t u64)//used in conv_manager in server mode.for server we have to use one udp fd for one conv(udp connection),
+//so we have to close the fd when conv expires
+{
+	int fd64=u64;
+	assert(fd_manager.exist(fd64));
+	fd_manager.close(fd64);
+}
 
 conv_manager_t::conv_manager_t()
 	{
 		clear_it=conv_last_active_time.begin();
 		long long last_clear_time=0;
-		//clear_function=0;
 	}
 conv_manager_t::~conv_manager_t()
 	{
@@ -85,7 +90,7 @@ conv_manager_t::~conv_manager_t()
 	{
 		return conv_last_active_time[conv]=get_current_time();
 	}
-	int conv_manager_t::insert_conv(u32_t conv,u64_t u64)
+	int conv_manager_t::insert_conv(u32_t conv,u64_t u64)//////todo add capacity
 	{
 		u64_to_conv[u64]=conv;
 		conv_to_u64[conv]=u64;
@@ -118,7 +123,6 @@ conv_manager_t::~conv_manager_t()
 	{
 		if(disable_conv_clear) return 0;
 
-
 		//map<uint32_t,uint64_t>::iterator it;
 		int cnt=0;
 		it=clear_it;
@@ -189,7 +193,8 @@ conv_manager_t::~conv_manager_t()
 	 mp[u64];
 	 return 0;
  }*/
- conn_info_t *& conn_manager_t::find_insert_p(ip_port_t ip_port)  //be aware,the adress may change after rehash
+ conn_info_t *& conn_manager_t::find_insert_p(ip_port_t ip_port) //todo capacity
+ //be aware,the adress may change after rehash
  {
 	 u64_t u64=ip_port.to_u64();
 	 unordered_map<u64_t,conn_info_t*>::iterator it=mp.find(u64);
@@ -305,14 +310,3 @@ int conn_manager_t::clear_inactive0()
 	return 0;
 }
 
-
-void server_clear_function(u64_t u64)//used in conv_manager in server mode.for server we have to use one udp fd for one conv(udp connection),
-//so we have to close the fd when conv expires
-{
-	int fd64=u64;
-	int ret;
-	assert(fd_manager.exist(fd64));
-	int fd=fd_manager.to_fd(fd64);
-
-	fd_manager.close(fd64);
-}
diff --git a/connection.h b/connection.h
index 14c6b13..72490f1 100644
--- a/connection.h
+++ b/connection.h
@@ -36,11 +36,9 @@ struct conv_manager_t  // manage the udp connections
 	//typedef hash_map map;
 	unordered_map<u64_t,u32_t> u64_to_conv;  //conv and u64 are both supposed to be uniq
 	unordered_map<u32_t,u64_t> conv_to_u64;
-
 	unordered_map<u32_t,u64_t> conv_last_active_time;
 
 	unordered_map<u32_t,u64_t>::iterator clear_it;
-
 	unordered_map<u32_t,u64_t>::iterator it;
 	unordered_map<u32_t,u64_t>::iterator old_it;
 
diff --git a/fd_manager.h b/fd_manager.h
index adaf0ca..014f0fb 100644
--- a/fd_manager.h
+++ b/fd_manager.h
@@ -14,7 +14,7 @@
 
 
 struct fd_manager_t   //conver fd to a uniq 64bit number,avoid fd value conflict caused by close and re-create
-//not used currently
+//this class is not strictly necessary,it just makes epoll fd handling easier
 {
 	fd_info_t & get_info(fd64_t fd64);
 	int exist_info(fd64_t);
diff --git a/main.cpp b/main.cpp
index 2259cd4..6525303 100644
--- a/main.cpp
+++ b/main.cpp
@@ -210,13 +210,14 @@ int client_event_loop()
 				dest.conv=conv;
 				my_send(dest,data,data_len);
 			}
-			else if (events[idx].data.u64 == remote_fd64)
+			else if(events[idx].data.u64>u32_t(-1) )
 			{
 				char data[buf_len];
-				if(!fd_manager.exist(remote_fd64))   //fd64 has been closed
+				if(!fd_manager.exist(events[idx].data.u64))   //fd64 has been closed
 				{
 					continue;
 				}
+				assert(events[idx].data.u64==remote_fd64);
 				int fd=fd_manager.to_fd(remote_fd64);
 				int data_len =recv(fd,data,max_data_len,0);
 				mylog(log_trace, "received data from udp fd %d, len=%d\n", remote_fd,data_len);
@@ -258,11 +259,6 @@ int client_event_loop()
 				mylog(log_trace,"epoll_trigger_counter:  %d \n",epoll_trigger_counter);
 				epoll_trigger_counter=0;
 			}*/
-
-			else if(events[idx].data.u64>u32_t(-1) )
-			{
-				assert(!fd_manager.exist(events[idx].data.u64));//this fd64 has been closed
-			}
 			else
 			{
 				mylog(log_fatal,"unknown fd,this should never happen\n");