Wireshark · Wireshark-users: Re: [Wireshark-users] Ethernet flow control

["Jake Peavy" <djstunks@xxxxxxxxx>]

On 12/4/08, Jake Peavy <djstunks@xxxxxxxxx> wrote:

Hello all,

I believe we're running into an issue caused by one device sending PAUSE frames onto the wire and impairing the bandwidth delivered by the upstream switch.

I have placed a 10BaseT hub (old school) in the datapath and attempted to capture this information using a linux host running Wireshark, but I do not see any flow control information.

Is there anything I need to do to the ethernet driver/interface in order to capture this traffic using Wireshark?

Hi all,

I found the following page which seems to indicate that Ethernet flow control is performed in hardware on most NICs and, as a result, the packets aren't passed into either kernel or userspace for analysis.

http://article.gmane.org/gmane.network.tcpdump.devel/2054

This appears to be the problem I'm encountering.  I was able to use a piece of test equipment to verify the presence of the PAUSE frames but I'd still like to be able to get these into the OS for Wireshark to see.

If anyone has any ideas on how to configure a NIC to present these frames, or can provide the make/model of a NIC that has this option that would be great.

Thanks,

-- 
-jp

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