VLAN mismatch message

Unanswered Question
Oct 17th, 2007

I have an older 2924xl connected to a 3550 switch and on the 2924xl I am getting the following:

%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/24 (0), with WKF-UNI-SW-A FastEthernet0/18 (200).

The 2924 with fa0/24 supports VLAN 1 only and the 3550 with fa0/18 is configured with VLAN 200.

What is the command to resolve this?

Is it applied to the 2924 or 3550?

I have this problem too.
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glen.grant Wed, 10/17/2007 - 13:58

This is informational only and doesn't bother anything . The only way is to match the native vlans on each end unless you want to turn off cdp as you see it is a cdp message. We see this all the time and we just leave it alone as it has no effect on traffic .

Nathan Eger Wed, 10/17/2007 - 14:36

The "native vlan" is the vlan in which untagged frames are tagged with 802.1q fields when traversing across trunk links.

The error %CDP-4-NATIVE_VLAN_MISMATCH, means that one of the switches (the 3550 most likely) has a native vlan set to something other than vlan 1.

Use the switchport trunk native interface configuration command to set the native VLAN for untagged traffic when in 802.1Q trunking mode.

on the 3550

sh run int fa0/18

look for the "switchport trunk native vlan" note the vlan id

on the 2900

config t

int fa0/24

switchport trunk native vlan (id number from 3550)


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