Native Vlan Mismatch on access link??

[frenzeus]

I have a Cat4506 with a SupII running CatOS 7.6. The 10/100 modules with their ports configured into respective vlans. Trunking has been set to off on the ports. So when i plug in Catalyst 2950 switches, it forms an access link, not a trunk but on the Cat4506 it receives msgs like such:

%CDP-4-NVLANMISMATCH:Native vlan mismatch detected on port 2/11

I only find that the C2950 switches running 12.1(19)EA1c plugged into the Cat4 has the Cat4 producing error msgs of native vlan mismatch. Other C2950 switches running slightly older version is not having the Cat4 producing the errors. I couldn't find any bugs on the IOS version. The configuration of the switches is a simple one, nothing fancy.

[milan.kulik · Accepted solution]

Hi,

if it is absolutely necessary to use different VLANs on the opposite access line sides (not recommended), there are some possibilities how to stop bothering error messages without disabling CDP completely:

a) The native VLAN info comes from CDP ver 2. So if you use CDP ver 1 instead of ver 2, the messages will stop.

b) On CatOS switches you can use

set logging level cdp 3 default

command. (I'm using it on Cat4000 and it works fine.)

Regards,

Milan

[frenzeus]

Hi Milan,

Thanks. Never knew that CDP v2 is the cause of this irritation!

Just what i need w/o much trouble!!

[terryyau]

I am experiencing the same problem (using C2950 with newer IOS version, like 12.1(20)) as frenzeus too. Are there any offical reply from Cisco about this problem?