Wireshark-users: Re: [Wireshark-users] TCP retransmissions from Windows file server
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From: Hansang Bae <hbae@xxxxxxxxxx>
Date: Mon, 09 Mar 2009 20:20:24 -0400
At 10:50 AM 2/19/2009, Hans van Staveren wrote:
>While figuring out the (slightly disappointing) performance from some
>Windows file servers in a corporate environment I found some TCP
>retransmissons using wireshark. Looking at the 'netstat -s -p tcp' output
>from the servers themselves I found a TCP segment retransmission rate of
>about 1%. My feeling is that this is a lot, given the fact that the whole
>network consists of three Cisco switches and two pieces of fiber.
>
>1) Is my gut feeling right about 1% retransmissions being a lot in this
>environment?
>2) The server guys told me they were using the HP teams driver on the
>servers, and that they heard that this would be a problem with Cisco
>switches. This does not ring any bell with me.


Others might have already chimed in, but 1% packet loss on a three switch network is pretty high.  

Are you sure you don't have a duplex mismatch?  Rule that out first.

hsb