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native VLAN issue on 2900XL/3500XL

I currently have TAC case open on this but I thought I would go ahead and start a thread here and see what others think...

We currently have over 200 2900/3500XL's left in our production environment. We recently finished our yearly IOS upgrade and moved all these series switches to the latest IOS (WC13), most of them had WC10.

After the upgrade (reload of the switches) we noticed many of the switches lost their CDP neighbor info. The switches are otherwise working fine, trunks are still up and users are having no issue. However this is wreaking havco on Cisco works "Topology Services". The CDP neighbor info is simply gone. Also when you do a debug CDP packet on the switches you never see any of the switches "receive" CDP packets back only send them.

Our standard config is to use a native VLAN of 999 and not include it on the trunks (per Cisco best practice). Basically what we have noticed is the only way to get CDP to work with any WC IOS past 10 is to include the native VLAN on the trunk.

My question is why would Cisco revert back to this as a default (non best practice)?

One more interesting thing is when a 2900/3500XL running WC13 is trunked (connected) to anything else (2950, 3750, 4506, etc) the CDP info works and shows up fine.


Re: native VLAN issue on 2900XL/3500XL

We have seen some of this also , just on nontrunked links back to routers or mls's . A lot of the time i have been to get them to work by doing a "clear interface F0/X on both sides . I don't know if this would be disruptive on a trunk link or not as we don't trunk these old boxes . You have to do the clear command on both sides of the link if one side does not work , you may have to wait for the cdp timers after the clear command to see if it worked or not . May not work at all on a trunk link I don't know but it's something to try to if it will kick start the cdp process. Personally I think it is a bug but they probably won't fix it because these are EOL and EOS .