Re: [lwip-devel] TCP MSS question

[Kieran Mansley]

On Sun, 2007-10-28 at 19:19 +0100, address@hidden wrote:
> Two questions about our TCP implementation:
> 
> - RFC 1122 says TCP should send with an MSS of "536 if no MSS option is 
> received" (chapter 4.2.2.6). We send with our configured TCP_MSS 
> instead. Since even Windows sends with 536 (btw: what does linux do?), 
> we should maybe change our code to meet the RFC?

Yes, I think we should change to use a max of 536 in those cases.  It's
perhaps a bit out dated for local area networks, but can still make
sense when running over longer links.

> - tcp_parseopt() doesn't allow a send MSS (advertised by the remote 
> side) to be larger than the configured TCP_MSS. Is this included in 
> order to configure memory usage or does it have other reasons?

I'm happier leaving that one as it is, as I suspect it does make
configuring memory usage simpler if we can know in advance what the
upper limit will be on received segments.

Kieran