Solved: Show CDP neighbor

wuh · ‎02-25-2009

SiteA-DSW1-ASW1--WL--SiteB-DSW1.

IP address configured on both DSW switches in the diagram.

On the interface on DSW1, it shows both the other two siwtches when you do show cdp neighbor on any of the interfaces of all 3 interaces of each of the switches.

How it is so? my understanding is that it only shows ASW1 if you do "show cdp neighbor" on the SiteA-DSW1.

Thanks,

Han

Giuseppe Larosa · ‎02-25-2009

Hello Han,

I do think so

the radio device should just perform a basic check of ethernet frame integrity before sending it on air

Hope to help

Giuseppe

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Giuseppe Larosa · ‎02-25-2009

Hello Han,

are all Cisco devices involved here ?

What are the models and IOS versions ?

Is the link a L2 trunk ?

Ther is any form of EoMPLS or other L2 transport service involved ?

Hope to help

Giuseppe

wuh · ‎02-25-2009

Giuseppe:

are all Cisco devices involved here ? All 3 switches are from cisco.

What are the models and IOS versions ?

SiteA-DSW1: 6500 with Version 12.2(18)

ASW: 4000 L3 Version 12.2(25)EWA5

SiteB-DSW1:6500 with Version 12.2(18)

Is the link a L2 trunk ?

The link between SiteA-DSW1 and SW1 is L2 trunk.

Ther is any form of EoMPLS or other L2 transport service involved ? Shouldn't.

Thanks,

Han

Giuseppe Larosa · ‎02-25-2009

Hello Han,

here I would start to investigate the device in the middle:

because it should be the one that forwards the multicast CDP frames causing to see multiple neighbors.

Hope to help

Giuseppe

wuh · ‎02-25-2009

Giuseppe:

forgot to mention.

WL in the middle = Radio.

Does a radio device forward multicast frames?

Thanks,

Han

Giuseppe Larosa · ‎02-25-2009

Hello Han,

I do think so

the radio device should just perform a basic check of ethernet frame integrity before sending it on air

Hope to help

Giuseppe