Re: Sliding windows on XP and 2K don't???

From: Chris P. [MVP] (msdn_at_chrisnet.net)
Date: 07/14/04 

Date: Wed, 14 Jul 2004 11:18:41 -0400

Steve Alpert wrote:
> We've been trying to speed up an application and have looked at a few
> sniffs and have found that when we're talking to a host (apparently
> with Nagle enabled), Windows XP will not transmit a second packet
> until a first packet has been ack'ed! We send a packet of about 30
> bytes followed almost immediately by a send of another packet of
> about 300 bytes and the second always waits until the server has
> ack'ed the first one? How come?
>
> These packet sizes are certainly small enough that the sliding window
> should come into play.

This is TCP, so don't think in terms of packets, it's a stream. At the
lowest level things are transmitted as packets obviously, and in your case
with Nagle turned on these two sends would get sent out as a single packet.

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