Re: SV: [lwip-users] TCP problem

[Kieran Mansley]

On Wed, 2009-10-21 at 12:15 +0100, Kieran Mansley wrote:
> On Tue, 2009-10-20 at 18:51 +0200, address@hidden wrote:
> > Continuing this on lwip-devel...
> > 
> > Jan Wester wrote:
> > > Hi
> > > I change my WND to 1024 (2*MSS) and now it works
> > >
> > > Thanks Simon and Kieran for your help
> > >   
> > Kieran, I studied Jans wireshark logs and indeed it looks a little 
> > strange that the window doesn't open unless it reaches 0, although lwIP 
> > was sending ACKs all the time. Is this an intention of the window update 
> > threshold mechanism? I thought it was only to not send (duplicate) ACKs 
> > that only contain window updates, not to prevent window changes at all?
> 
> My intention was that it would only affect the sending of explicit
> window updates.  Normal ACKs should contain an up-to-date window.  There
> might be some "silly window avoidance" that is getting in the way.

Yep, this is the case: the silly window avoidance means we update the
advertised window only when it increases by at least one MSS.

Kieran