Re: [lwip-users] TCP timer intervals

[Kieran Mansley]

On 31 Mar 2012, at 19:55, Christoph Baier wrote:

> Hello,
> 
> since my TCP connections are established inside a low latency (non-public) 
> network (10-100usec RTT), in order to speed up retransmissions I am thinking 
> to reduce the TCP_TMR_INTERVAL in lwip to 1 or 10 msec.
> 
> Any thoughts on issues that could arise with this change? Any other changes 
> recommended for low latency networks?

It will probably be fine in that environment.  In general I would hope that the 
fast retransmission mechanism would be handling most of the retransmissions, 
but perhaps your traffic pattern doesn't let that kick in.  TCP does have 
algorithms to try to measure the RTT and use that to adjust the retransmission 
timer, but I can't remember off the top of my head if lwIP does that yet.

Kieran