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Wireshark-users: Re: [Wireshark-users] Detecting Duplex Mismatch with Wireshark

From: "Luis EG Ontanon" <luis@xxxxxxxxxxx>
Date: Thu, 20 Nov 2008 19:14:52 +0100
AFAIK there's little Wireshark can see there, neither mirror (SPAN)
ports nor libpcap pass collisions or garbled frames.

but we know that

duplex mismatch = sensitive increase of collision count on the half-duplex side.
Whic in turn is packet loss and that is AFAIK the only thing wireshark
can infer as there are lots of TCP retransmissions (as well as dup
acks) towards the half-duplex side.

\Lego

On Thu, Nov 20, 2008 at 5:04 PM, Barry Constantine
<Barry.Constantine@xxxxxxxx> wrote:
> Hello,
>
>
>
> Duplex mismatches are still a surprisingly common problem, especially
> between workstations and switches, etc.
>
>
>
> If CDP is present, it is very straight forward to detect duplex mismatches
> in pcap files, since the devices publish the duplex setting in the CDP
> message.
>
>
>
> Does anyone know if there is a way to detect duplex mismatches within a
> normal pcap file (non-CDP) that is captured between two devices with the
> mismatch?
>
>
>
> Thanks,
>
> Barry
>
>
>
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