CDP-EV: Bad checksum in header

[manuel-mendez]

Hello,

I have a 3560 (ios 12.2(25)) connected to L3 module (ios 12.0(14)) on catalyst 4006.

I can see 3560 as a CDP neighbour on L3 module, but I can NOT see L3 module on 3560 as CDP neighbour

L3 communications are OK.

debug cdp events on 3560 shows:

CDP-EV: Bad checksum in header

show cdp traffic on 3560 shows checksum errors:

Chksum error: 13

cdp v2 ads. are disable on 3560

Can you help me. Thanks.

manuel.

pd. I know this is little problem because IP communication is OK, but you know costumers...

[didyap]

If the trunk link between the router and the switch is ISL there could be some issues.It includes ISL header length, which cause bad checksum.Also check to see if they are using same version.