Re: Strange CDP Observation

I also saw this same effect of a switch appearing as its own neighbor when
using 2 links in a flex link setup to connect to a non-Cisco switch. The
switch saw itself as a CDP neighbor on each flex link port through the 3rd
party switch.

Nate

On Sat, Nov 28, 2009 at 5:40 PM, Joe Astorino <jastorino_at_ipexpert.com>wrote:

> Yes you have a loop somewhere in your L2 network that you need to trace
> down. I have seen this before and it turned out to be a hub stuck somewhere
> in the middle of a loop.
>
> Switch1--hub--Switch1
> ------Original Message------
> From: Ernest McCaleb
> Sender: nobody_at_groupstudy.com
> To: Felix Nkansah
> Cc: cisco-nsp_at_puck.nether.net
> Cc: CCIE Groupstudy
> ReplyTo: Ernest McCaleb
> Subject: Re: Strange CDP Observation
> Sent: Nov 28, 2009 6:24 PM
>
> There is a loop someplace.
>
> Ernest #21508
>
> On Sat, Nov 28, 2009 at 5:42 PM, Felix Nkansah <felixnkansah_at_gmail.com
> >wrote:
>
> > Hi Team,
> >
> > One of my field engineers at a remote site has reported a problem to me,
> > one
> > which I find rather strange but yet to confirm for myself.
> >
> > A Catalyst 2960 switch at the remote site is linked to a switch at a
> > Central
> > site via radio (bridged).
> >
> > However, besides the fact that connectivity tests between the two sites
> are
> > failing, his observation is that when he issues the "SHOW CDP NEI"
> command
> > on the remote C2960 switch, he sees the switch itself appearing as its
> > neighbor rather than the other switch at the central location which is
> > typically the output he expected.
> >
> >
> > I have personally never seen a Cisco device showing itself as it's own
> > neighbor in a 'show cdp neighbor' output.
> >
> > What do you know to be the cause of this problem?
> >
> > Thanks.
> >
> >
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> >
> >
> >
> >
>
>
> --
> Ernest McCaleb
>
>
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>
>
>
> Regards,
>
> Joe Astorino - CCIE #24347 R&S
> Technical Instructor - IPexpert, Inc.
> Cell: +1.586.212.6107
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Received on Sat Nov 28 2009 - 19:34:00 ART