Re: Strange CDP Observation

While not normal, think about what makes it occur.

If it REALLY WAS your own CDP frame, then your link should be down due
to loopguard. Even with a hub there, a hub is a repeater, so is ti
feasible to see your own stuff?

1. When you do "show interface" does it say "looped" at all?
2. Assuming that regular data moves just fine, it's not a loop
3. Back to "show interface" are you seeing it as half duplex? You may
be if this is a radio device, but that depends on the specifics.
4. When you do "show cdp neighbor (int) detail" is the IP address the
same as yours or different?

I'd sooner think it was a misconfiguration of the other side's switch.
If all you're doing is L2 stuff on them, you'll probably not notice any
functional impact. but I've seen more than one customer where EVERY
switch had identical configuration, including "management IP" and
"hostname" which makes things REALLY confusing to manage, but fully
working at L2.

HTH,

*Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,

JNCIE-M #153, JNCIS-ER, CISSP, et al.

JNCI-M, JNCI-ER

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Felix Nkansah 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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Received on Sun Nov 29 2009 - 03:46:06 ART