[c-nsp] %CDP-4-DUPLEX_MISMATCH - But they aren't connected!

[Tassos Chatzithomaoglou]

"no cdp advertise-v2" will stop these messages, since the "unmatching duplex" reporting 
functionality (+ native vlan mismatch) has been added in CDP v2.

--
Tassos


Jay Hennigan wrote on 3/12/2007 7:30 πμ:
> Tuc at T-B-O-H.NET wrote:
>> Hi,
>>
>> 	I'm getting on a 3640 running (C3640-JK9S-M), Version 12.4(13a) :
>>
>> Dec  1 13:07:26 EST: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on Ethernet0/0 (not full duplex), with c2924-1.house.tucs-beachin-obx-house.com FastEthernet0/15 (full duplex).
>>
>> 	The problem is that E0/0 is 10/half and facing a transit provider,
>> while E0/1 is part of a bridge group with E1/1, and E0/1 also at 10/half
>>  connects to port FA0/24 on c2924-1.house.tucs-beachin-obx-house.com (At
>> 10/half). Port FA0/15 is connected to a consumer Ethernet over Power extender....
>> (And yea, THAT is 100 full).
>>
>> 	Does CDP need EVERYTHING to be running the same speed/duplex even
>> when not connected directly together?
> 
> You'll often see that problem when there are non-Cisco layer 2 devices 
> between the neighbors.
> 
> Some non-Cisco gear relays CDP frames out all interfaces which results 
> in CDP reporting direct connections which in reality are not.  The only 
> workaround of which I am aware is to disable CDP on those interfaces or 
> ignore the error reports.
> 
> --
> Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
> Impulse Internet Service  -  http://www.impulse.net/
> Your local telephone and internet company - 805 884-6323 - WB6RDV
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