[lwip-users] Send buffers

[David Aldrich]

Hi

I now have lwIP working nicely with my application.  I do have one
issue, however, that I would like to discuss.

My application receives messages from another processor on the same card
and transmits these messages to a PC over a TCP/IP connection.  My
application cannot control the rate at which the other processor
generates these messages.  My code simply discards the messages until
the TCP/IP connection is established and then sends then down the lwIP
stack.

I have found that my processor can cope with the data rate from the
other processor in steady-state, but for a short period after connection
establishment I get lwIP send buffer overflow.  I assume that this is
caused by the slow start algorithm.  After about a second, things settle
down, and no data is lost.

My question is how should I cope with this situation?

I think that my only option is to increase the number of send buffers in
lwIP to cope with the slow start.  What #defines in lwipopts.h should I
modify?

I would be interested to hear how applications should deal with this
type of situation in general.  Does it imply that there should be some
flow control at the application level?

Thanks for your help,

David