Troubleshooting TCP performance tutorial

Kevin Oberman oberman at
Sat Sep 18 05:37:46 UTC 2010

> Date: Fri, 17 Sep 2010 20:06:09 -0400
> From: "Abel Alejandro" <aalejandro at>
> Greetings,
> This past week I have been trying to find the root cause of tcp
> performance problems of a few clients that are using a third party metro
> Ethernet for transport. RFC2544 tests (Layer 2) and iperf using UDP give
> good symmetric performance almost 100% the speed of the circuit. However
> all kind of TCP tests result in some kind of asymmetrical deficiency,
> either the upstream or downstream of the client is hugely different. The
> latency is not a huge factor since all the metro Ethernet connections
> have less than 2 ms.
> So the question basically if is there a good tutorial or white paper for
> troubleshooting tcp with emphasis of using tools like Wireshark to debug
> and track this kind of problems.
> Regards,
> Abel.

You might look at A lot of it is aimed at very
large volume data transfers, but quite a bit is relevant to all TCP
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751

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