diff --git a/connection.cpp b/connection.cpp
index f285448..12fdd7f 100644
--- a/connection.cpp
+++ b/connection.cpp
@@ -11,7 +11,6 @@ const int disable_conv_clear=0;//a udp connection in the multiplexer is called c
 
 const int disable_conn_clear=0;//a raw connection is called conn.
 
-conn_manager_t conn_manager;
 
 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
diff --git a/fec_manager.cpp b/fec_manager.cpp
index b41cb77..47f2e54 100644
--- a/fec_manager.cpp
+++ b/fec_manager.cpp
@@ -40,13 +40,13 @@ int blob_encode_t::get_shard_len(int n,int next_packet_len)
 
 int blob_encode_t::input(char *s,int len)
 {
-	assert(current_len+len+sizeof(u16_t) <=max_fec_packet_num*buf_len);
+	assert(current_len+len+sizeof(u16_t) +100<sizeof(input_buf));
 	assert(len<=65535&&len>=0);
 	counter++;
 	assert(counter<=max_fec_pending_packet_num);
-	write_u16(buf+current_len,len);
+	write_u16(input_buf+current_len,len);
 	current_len+=sizeof(u16_t);
-	memcpy(buf+current_len,s,len);
+	memcpy(input_buf+current_len,s,len);
 	current_len+=len;
 	return 0;
 }
@@ -54,12 +54,12 @@ int blob_encode_t::input(char *s,int len)
 int blob_encode_t::output(int n,char ** &s_arr,int & len)
 {
 	len=round_up_div(current_len,n);
-	write_u32(buf,counter);
+	write_u32(input_buf,counter);
 	for(int i=0;i<n;i++)
 	{
-		output_arr[i]=buf+len*i;
+		output_buf[i]=input_buf+len*i;
 	}
-	s_arr=output_arr;
+	s_arr=output_buf;
 	return 0;
 }
 blob_decode_t::blob_decode_t()
@@ -82,8 +82,8 @@ int blob_decode_t::input(char *s,int len)
 	counter++;
 	assert(counter<=max_fec_packet_num);
 	last_len=len;
-	assert(current_len+len+100<(int)sizeof(buf));
-	memcpy(buf+current_len,s,len);
+	assert(current_len+len+100<(int)sizeof(input_buf));//avoid overflow
+	memcpy(input_buf+current_len,s,len);
 	current_len+=len;
 	return 0;
 }
@@ -92,21 +92,21 @@ int blob_decode_t::output(int &n,char ** &s_arr,int *&len_arr)
 
 	int parser_pos=0;
 
-	if(parser_pos+(int)sizeof(u32_t)>current_len) return -1;
+	if(parser_pos+(int)sizeof(u32_t)>current_len) {mylog(log_info,"failed 0\n");return -1;}
 
-	n=(int)read_u32(buf+parser_pos);
+	n=(int)read_u32(input_buf+parser_pos);
 	if(n>max_fec_pending_packet_num) {mylog(log_info,"failed 1\n");return -1;}
-	s_arr=s_buf;
-	len_arr=len_buf;
+	s_arr=output_buf;
+	len_arr=output_len;
 
 	parser_pos+=sizeof(u32_t);
 	for(int i=0;i<n;i++)
 	{
 		if(parser_pos+(int)sizeof(u16_t)>current_len) {mylog(log_info,"failed2 \n");return -1;}
-		len_arr[i]=(int)read_u16(buf+parser_pos);
+		len_arr[i]=(int)read_u16(input_buf+parser_pos);
 		parser_pos+=(int)sizeof(u16_t);
 		if(parser_pos+len_arr[i]>current_len) {mylog(log_info,"failed 3 %d  %d %d\n",parser_pos,len_arr[i],current_len);return -1;}
-		s_arr[i]=buf+parser_pos;
+		s_arr[i]=input_buf+parser_pos;
 		parser_pos+=len_arr[i];
 	}
 	return 0;
@@ -123,6 +123,7 @@ fec_encode_manager_t::fec_encode_manager_t()
 	timer_fd64=fd_manager.create(timer_fd);
 
 	re_init(4,2,1200,100,10000,0);
+	seq=(u32_t)get_true_random_number(); //TODO temp solution for a bug.
 }
 fec_encode_manager_t::~fec_encode_manager_t()
 {
@@ -141,10 +142,11 @@ int fec_encode_manager_t::re_init(int data_num,int redundant_num,int mtu,int pen
 	fec_pending_time=pending_time;
 	this->type=type;
 
+	assert(data_num+redundant_num<255);
 	counter=0;
 	blob_encode.clear();
 	ready_for_output=0;
-	seq=0;
+	//seq=0;
 
 	itimerspec zero_its;
 	memset(&zero_its, 0, sizeof(zero_its));
@@ -166,14 +168,14 @@ int fec_encode_manager_t::append(char *s,int len/*,int &is_first_packet*/)
 	}
 	if(type==0)
 	{
-		blob_encode.input(s,len);
+		assert(blob_encode.input(s,len)==0);
 	}
 	else if(type==1)
 	{
 		mylog(log_trace,"counter=%d\n",counter);
 		assert(len<=65535&&len>=0);
 		char * p=input_buf[counter]+sizeof(u32_t)+4*sizeof(char);
-		write_u16(p,(u16_t)((u32_t)len));
+		write_u16(p,(u16_t)((u32_t)len));  //TODO  omit this u16 for data packet while sending
 		p+=sizeof(u16_t);
 		memcpy(p,s,len);//remember to change this,if protocol is modified
 		input_len[counter]=len+sizeof(u16_t);
@@ -190,6 +192,8 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
 	int about_to_fec=0;
 	int delayed_append=0;
 	//int counter_back=counter;
+	assert(type==0||type==1);
+
 	if(type==0&& s!=0 &&counter==0&&blob_encode.get_shard_len(fec_data_num,len)>=fec_mtu)
 	{
 		mylog(log_warn,"message too long len=%d,ignored\n",len);
@@ -200,10 +204,15 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
 		mylog(log_warn,"message too long len=%d,ignored\n",len);
 		return -1;
 	}
+	if(s==0&&counter==0)
+	{
+		mylog(log_warn,"unexpected s==0&&counter==0\n");
+		return -1;
+	}
 	if(s==0) about_to_fec=1;//now
 
-	assert(type==0||type==1);
 	if(type==0&& blob_encode.get_shard_len(fec_data_num,len)>=fec_mtu) {about_to_fec=1; delayed_append=1;}//fec then add packet
+
 	if(type==0) assert(counter<fec_pending_num);
 	if(type==1) assert(counter<fec_data_num);
 
@@ -215,7 +224,6 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
 
 	if(type==0&& counter==fec_pending_num) {about_to_fec=1;} //
 
-
 	if(type==1&& counter==fec_data_num) about_to_fec=1;
 
 
@@ -224,9 +232,10 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
     	char ** blob_output;
     	int fec_len=-1;
     	mylog(log_trace,"counter=%d\n",counter);
+
     	if(counter==0)
     	{
-    		mylog(log_warn,"unexpected counter==0\n");
+    		mylog(log_warn,"unexpected counter==0 here\n");
     		return -1;
     	}
 
@@ -238,7 +247,7 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
     		actual_data_num=fec_data_num;
     		actual_redundant_num=fec_redundant_num;
 
-        	blob_encode.output(actual_data_num,blob_output,fec_len);
+        	assert(blob_encode.output(actual_data_num,blob_output,fec_len)==0);
     	}
     	else
     	{
@@ -273,7 +282,6 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
 			}
 			input_buf[i][tmp_idx++] = (unsigned char) i;
 
-
     		tmp_output_buf[i]=input_buf[i]+tmp_idx; //////caution ,trick here.
 
     		if(type==0)
@@ -295,14 +303,14 @@ int fec_encode_manager_t::input(char *s,int len/*,int &is_first_packet*/)
     				output_len[i]=tmp_idx+fec_len;
 
     		}
-    		output_buf[i]=input_buf[i];
+    		output_buf[i]=input_buf[i];//output_buf points same block of memory with different offset
 
     	}
     	//output_len=blob_len+sizeof(u32_t)+4*sizeof(char);/////remember to change this 4,if modified the protocol
 		rs_encode2(actual_data_num,actual_data_num+actual_redundant_num,tmp_output_buf,fec_len);
 
 		//mylog(log_trace,"!!! s= %d\n");
-
+		assert(ready_for_output==0);
     	ready_for_output=1;
     	seq++;
     	counter=0;
@@ -432,20 +440,27 @@ int fec_decode_manager_t::input(char *s,int len)
 		}
 	}
 
-	if(data_num+redundant_num>max_fec_packet_num)
+	if(data_num+redundant_num>=max_fec_packet_num)
 	{
 		mylog(log_info,"failed here\n");
 		return -1;
 	}
 	if(!anti_replay.is_vaild(seq))
 	{
-		//mylog(log_info,"failed here2\n");
+		mylog(log_trace,"!anti_replay.is_vaild(seq) ,seq =%u\n",seq);
 		return 0;
 	}
 
 	if(mp[seq].group_mp.find(inner_index)!=mp[seq].group_mp.end() )
 	{
-		mylog(log_info,"dup inner_index\n");
+		mylog(log_debug,"dup fec index\n");
+		return -1;
+	}
+
+
+	if(type==0&&data_num==0)
+	{
+		mylog(log_warn,"unexpected here,data_num=0\n");
 		return -1;
 	}
 
@@ -457,13 +472,6 @@ int fec_decode_manager_t::input(char *s,int len)
 		if(mp[seq].type!=type) ok=0;
 	}
 
-	if(type==0&&data_num==0)
-	{
-		mylog(log_warn,"unexpected here,data_num=0\n");
-		return -1;
-	}
-
-
 	if(data_num!=0)
 	{
 		mp[seq].data_counter++;
@@ -486,13 +494,9 @@ int fec_decode_manager_t::input(char *s,int len)
 
 	if(ok==0)
 	{
-		//mylog(log_info,"ok=0\n");
+		mylog(log_warn,"fec data invaild\n");
 		return -1;
 	}
-	else
-	{
-		//mylog(log_info,"ok=1\n");
-	}
 
 	if(fec_data[index].used!=0)
 	{
@@ -504,6 +508,7 @@ int fec_decode_manager_t::input(char *s,int len)
 		}
 		if(tmp_seq==seq)
 		{
+			mylog(log_warn,"unexpected tmp_seq==seq ,seq=%d\n",seq);
 			return -1;
 		}
 	}
@@ -517,6 +522,7 @@ int fec_decode_manager_t::input(char *s,int len)
 	fec_data[index].len=len;
 	memcpy(fec_data[index].buf,s+tmp_idx,len);
 	mp[seq].group_mp[inner_index]=index;
+	//index++ at end of function
 
 	map<int,int> &inner_mp=mp[seq].group_mp;
 
@@ -606,7 +612,7 @@ int fec_decode_manager_t::input(char *s,int len)
 			{
 				fec_tmp_arr[it->first]=fec_data[it->second].buf;
 			}
-			rs_decode2(group_data_num,group_data_num+group_redundant_num,fec_tmp_arr,len); //the input data has been modified in-place
+			assert(rs_decode2(group_data_num,group_data_num+group_redundant_num,fec_tmp_arr,len)==0); //the input data has been modified in-place
 			blob_decode.clear();
 			for(int i=0;i<group_data_num;i++)
 			{
diff --git a/fec_manager.h b/fec_manager.h
index 97540a0..ad887b9 100644
--- a/fec_manager.h
+++ b/fec_manager.h
@@ -58,11 +58,11 @@ struct anti_replay_t
 
 struct blob_encode_t
 {
-	char buf[(max_fec_packet_num+5)*buf_len];
+	char input_buf[(max_fec_packet_num+5)*buf_len];
 	int current_len;
 	int counter;
 
-	char *output_arr[max_fec_packet_num+100];
+	char *output_buf[max_fec_packet_num+100];
 
 	blob_encode_t();
 
@@ -78,13 +78,13 @@ struct blob_encode_t
 
 struct blob_decode_t
 {
-	char buf[(max_fec_packet_num+5)*buf_len];
+	char input_buf[(max_fec_packet_num+5)*buf_len];
 	int current_len;
 	int last_len;
 	int counter;
 
-	char *s_buf[max_fec_pending_packet_num+100];
-	int len_buf[max_fec_pending_packet_num+100];
+	char *output_buf[max_fec_pending_packet_num+100];
+	int output_len[max_fec_pending_packet_num+100];
 
 	blob_decode_t();
 	int clear();
diff --git a/main.cpp b/main.cpp
index 8681d95..787c1aa 100644
--- a/main.cpp
+++ b/main.cpp
@@ -28,7 +28,9 @@ int jitter_max=0;
 int mtu_warn=1350;
 
 int disable_mtu_warn=0;
-int disable_fec=1;
+int disable_fec=0;
+
+int debug_force_flush_fec=0;
 
 int fec_data_num=20;
 int fec_redundant_num=10;
@@ -44,10 +46,12 @@ int local_port = -1, remote_port = -1;
 u64_t last_report_time=0;
 int report_interval=0;
 
-//conn_manager_t conn_manager;
+conn_manager_t conn_manager;
 delay_manager_t delay_manager;
 fd_manager_t fd_manager;
 
+
+
 const int disable_conv_clear=0;
 
 int socket_buf_size=1024*1024;
@@ -321,6 +325,20 @@ int client_event_loop()
 				read(conn_info.timer.get_timer_fd(), &value, 8);
 				conn_info.conv_manager.clear_inactive();
 				mylog(log_trace,"events[idx].data.u64==(u64_t)conn_info.timer.get_timer_fd()\n");
+
+				if(debug_force_flush_fec)
+				{
+				int  out_n;char **out_arr;int *out_len;int *out_delay;
+				dest_t dest;
+				dest.type=type_fd64;
+				dest.inner.fd64=remote_fd64;
+				dest.cook=1;
+				from_normal_to_fec(conn_info,0,0,out_n,out_arr,out_len,out_delay);
+				for(int i=0;i<out_n;i++)
+				{
+					delay_send(out_delay[i],dest,out_arr[i],out_len[i]);
+				}
+				}
 			}
 			else if (events[idx].data.u64 == (u64_t)local_listen_fd||events[idx].data.u64 == conn_info.fec_encode_manager.get_timer_fd64())
 			{
@@ -643,7 +661,7 @@ int server_event_loop()
 					fd_manager.get_info(fec_fd64).ip_port=ip_port;
 
 					conn_info.timer.add_fd64_to_epoll(epoll_fd);
-					conn_info.timer.set_timer_repeat_us(timer_interval*100);
+					conn_info.timer.set_timer_repeat_us(timer_interval*1000);
 
 					mylog(log_debug,"conn_info.timer.get_timer_fd64()=%llu\n",conn_info.timer.get_timer_fd64());
 
@@ -770,6 +788,10 @@ int server_event_loop()
 					uint64_t value;
 					read(conn_info.timer.get_timer_fd(), &value, 8);
 					conn_info.conv_manager.clear_inactive();
+					if(debug_force_flush_fec)
+					{
+					from_normal_to_fec(conn_info,0,0,out_n,out_arr,out_len,out_delay);
+					}
 					continue;
 				}
 				else