Question on windowing

Unanswered Question
Sep 25th, 2009

I just got hit with a troubleshooting question today, and didn't know how to answer. What does it mean when a packet has a window size of 0? TIA.


I have this problem too.
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prakkdangc Fri, 09/25/2009 - 09:34

It's called "closing the window" and is usually sent by a device that is getting TCP information much faster than it can respond to. It probably was prefaced by a shrinking of the window first.

I have usually seen it with overtaxed servers.


Joseph W. Doherty Fri, 09/25/2009 - 10:59

The receiving host is informing the sending host it's unable to accept any additional data. If this is seen, it's likely the receiving host does have some buffer space but is trying to avoid the TCP "silly window syndrome".


The reason for this happening is the receiving host can't keep up with the sending host's tranmission rate. This shouldn't be common since most network media is generally "slower" compared to processing performance of most modern hosts. However, as also noted by Dave, a very busy host might be unable to keep up with incoming network data.


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