Wireshark mailing list archives
Re: MTU - wireshark showing length longer than.
From: "George Peaslee" <gpeaslee () verizon net>
Date: Wed, 25 Nov 2009 11:46:43 -0600
How did you have the capture buffer set up? I've had some situations where I had to set it to 100MB when capturing a 10Gb link. I also turn of the updates during the trace. If you had it set to default, try making the trace with it set to 100MB and see if there's a difference. ----- Original Message ----- From: "Ant Mitchell" <ant () badmagic com> To: <wireshark-users () wireshark org> Sent: Wednesday, November 25, 2009 10:27 AM Subject: [Wireshark-users] MTU - wireshark showing length longer than.
Hi, I am new to wireshark and TCP diagnostics in general. I have a problem with a HP procurve switch that I am trying to diagnose. I have removed the switch from my config, and now have an xserve plugged into a centos box, both running 10gb myricom cards. Both ends have flow control enabled, and an MTU of 9000. I have double triple checked this. I have been running netperf tests across the link, mostly from the xserve to the centos box, and I see wireshark report packet lengths way in excess of the mtu. The throughput I am getting is about 2900 Mbps. How is the packet length being reported so large ?, sometimes these large packets seem to get acked and sometimes they don't , resulting in lost segments. The same large packets appear in tcpdump also, so its not a bug in wireshark. What should I be looking at ?, how does the packet size get larger than the MTU ?. A typical size is 8960 for several packets, then 17960 and 20456 and several inbetween. Thanks -- Ant ___________________________________________________________________________ Sent via: Wireshark-users mailing list <wireshark-users () wireshark org> Archives: http://www.wireshark.org/lists/wireshark-users Unsubscribe: https://wireshark.org/mailman/options/wireshark-users mailto:wireshark-users-request () wireshark org?subject=unsubscribe
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Current thread:
- MTU - wireshark showing length longer than. Ant Mitchell (Nov 25)
- Re: MTU - wireshark showing length longer than. Stephen Fisher (Nov 25)
- Re: MTU - wireshark showing length longer than. Ant Mitchell (Nov 25)
- Re: MTU - wireshark showing length longer than. George Peaslee (Nov 25)
- Re: MTU - wireshark showing length longer than. Stephen Fisher (Nov 25)