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Re: TCP stack not delaying/piggybacking ACKs?


On Mon, Jul 08, 2002 at 09:36:24PM -0400, Mark Salter wrote:
> >>>>> Grant Edwards writes:
> 
> > I've been browsing around the sources and haven't quite figured
> > out how it's supposed to work.  I do have the TCP_NODELAY flag
> > set on the socket, but I don't know if that has anything to do
> > with it.  That is easy enough to test.
> 
> Try turning it off. TCP_NODELAY tells the stack to send ACKs without
> waiting a bit for a possible packet to piggyback on.

Turning off TCP_NODELAY doesn't make any difference.  ACKs are
still sent out immediately.

I've read through the TCP stack sources and AFAICT, the only
place where NODELAY is checked is when tcp_output is trying to
figure out how much data to send.  [This agrees with my reading
of Stevens.]

Why ACKs aren't being delayed is apparently a different issue...

-- 
Grant Edwards
grante@visi.com

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