[lwip-users] problems with TCP transmission

[zb z]

Hi all,
   I have some problems in TCP transmission in lwip.I have used lwip
0.6.3 for a long time and I have read the code in lwip 1.1.0
recently.I use the raw API.
   The first problem is: Do I need call tcp_output MANUALLY? Assume a
tcp sender will send a lot of data to receiver,if the sender just send
data after polling callback,the performance is unacceptable.
   Second,why there is only ONE timer for each TCP connection to do
retransmission?the struct tcp_pcb has a field rtime,and it is cleared
when tcp_output_segment is called.I think this may cause some serious
problems:if the sender has a large send window and send data
periodly,it may cause the "first" segment to be timed out after the
"last" segment has be transmitted.
   I use lwip to transmit a lot of data on tcp,it works OK on LAN,but
has bad performance on WAN.

        Best Regards.
　　　　　　　　Zengbo Zhang