I use lwIP+PPP in GPRS environment. I am still meet the response slow problem.
The 80% time socket is used in this way
connect --> send --(1xx bytes) ---> receive (1xx bytes)---> disconnect.
What is suitable configureation for my case?
My current configuration is
#####################
#define TCP_QUEUE_OOSEQ 0
/* TCP Maximum segment size. */
#define TCP_MSS 1024
/* TCP sender buffer space (bytes). */
#define TCP_SND_BUF (TCP_MSS*4)
/* TCP sender buffer space (pbufs). This must be at least = 2 *
TCP_SND_BUF/TCP_MSS for things to work. */
#define TCP_SND_QUEUELEN (4 * TCP_SND_BUF/TCP_MSS)
/* TCP writable space (bytes). This must be less than or equal
to TCP_SND_BUF. It is the amount of space which must be
available in the tcp snd_buf for select to return writable */
#define TCP_SNDLOWAT (TCP_SND_BUF/2)
/* TCP receive window. */
#define TCP_WND (TCP_MSS*4) /*
minye.li original is 2048*/
##########################
The slow is cause in send, but the peer has a long delay to get the data. I am unable to confirm where the long delay comes from.
Lee