[lwip-users] how is the case "write more than sendbuf"?

[PHAM ANH THIEN]

Dear all,

I am testing a tcp sending application which send a lot buffer, each buffer got 1024 bytes. My version lwip is 1.3.1-rc1.

If my network application send too fast, then cause the case "don't try to write more than sendbuf" (in function do_writemore, api_msg.c). What i undestand this case my application send too fast and lwip slowly receive ACK so that it could not quickly release sendbuf then cause the size of sendbuf too small.

Do i understand correctly?
 
As my application encounter this case, it hangs and can not send data anymore.

Anyone faced this case, pls advise!

I notice that my macro in lwipopts as below:

/* Controls if TCP should queue segments that arrive out of
   order. Define to 0 if your device is low on memory. */
#define TCP_QUEUE_OOSEQ         1

#define TCP_MSS                 1500

#define TCP_SND_BUF             6*1500
/* TCP sender buffer space (pbufs). This must be at least = 2 *
   TCP_SND_BUF/TCP_MSS for things to work. */
#define TCP_SND_QUEUELEN        6 * TCP_SND_BUF/TCP_MSS

/* TCP receive window. */
#define TCP_WND                 1500

Thanks a lot.
Thien