Re: [lwip-users] Pbuf pool size and network interface

[Kieran Mansley]

On Fri, 2011-06-24 at 18:19 +0200, Enrico Murador - Research &
Development - CET wrote:
> > (1) 500 bytes is a very small window.  Please make sure you
> > set it to be at least 2*MSS to avoid very poor TCP performance;
> This is ok, as my application (luckily!) requires a very small MSS; I 
> have set
> the TCP window as 2 * MSS obtaining a window of about 620 bytes.

Is such a small MSS valid?  All IP networks are supposed to guarantee
that they can receive a segment of 576 bytes without fragmenting, so
assuming the default header sizes that would make a TCP segment of 536
bytes.  While setting it smaller might be OK in most situations, you
might find that this causes interoperability problems with other stacks,
as they could ignore your MSS request and just use 536 instead.

Kieran