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TCP Optimization on a fast link

Unanswered Question
Aug 18th, 2003
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Hi,

we're experiencing poor TCP performance on a Oc3 link because of high delay.(20ms)

The delay is because of length of the line.


I know that I can change the TCP window size to optimize the performance but I would have to do this on several hundreds PCs.


Does anybody know a better way to improve the performance? (e.g. some kind of magic blackbox which adapts the TCP window size)


Regards

Alex

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deilert Mon, 08/18/2003 - 05:13
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If you are experiencing poor performance with 20 ms response time , I would not start playing with the TCP window size, 20 ms response is excellent response time , I would have the application and server support start looking a little harder at there piece os the pie, this sounds like a classic exapmle of the application /server guys not knowing how to fix there problem and blaming the network .


To further support your case you can sniff the wire to determine what is causing the poor performance .


Good Luck

t.baranski Mon, 08/18/2003 - 17:25
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20ms isn't bad for a WAN but with a default maximum TCP window size of 64KB, you're limited to ~24mbits/sec per flow if my calculations are correct. I'm not aware of a device that can adjust TCP window values in existing TCP sessions -- offhand, the practicality of such a device seems questionable at best.

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