Hi, We are developing with LwIP 1.3.2 using callback routines (no RTOS or threads or sockets or ...). Using a ST Micro STR912, with Micrel KSZ8893MQL PHY.
I have implemented a HTTP server, and am now trying to implement POST processing for file upload. With fairly "standard" settings, the POST file upload resulted in a lot of retransmissions. What appeared to be occurring, was that the browser was sending multiple (2) packets before waiting for an ACK. This makes sense, because TCP_WND = 4 * TCP_MSS. But the TCP stack (or my handling of the stack) could not cope, resulting in the large number of retransmission requests. I made TCP_WND = TCP_MSS = 512, and all seems to work well. In 'opt.h', there was a warning which has me concerned: /** * TCP_WND: The size of a TCP window. This must be at least * (2 * TCP_MSS) for things to work well */ Will this be an issue? What issues (besides performance)? Is it possible to have TCP_WND = TCP_MSS for packet reception, but have the recommended TCP_WND = 4 * TCP_MSS for packet transmission? If so, pointers on where to look would be good. Regards, Mykola Kyrylenko _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
