different Native vlans on the ends of trunk link...

Cyclades

Hello Guys...

I am have a doubt in trunking.

If I configure different native vlan on each ends of a trunk, will trunking will still work or not ?

luke_bibby

A trunk with mismatched native VLANs will still stay operational. Here's one I prepared earlier:

On switch B:
SwitchB#sh int tru

Port Mode Encapsulation Status Native vlan
Fa0/15 auto 802.1q trunking 2

Port Vlans allowed on trunk
Fa0/15 1-4094

Port Vlans allowed and active in management domain
Fa0/15 1,10,15,20

Port Vlans in spanning tree forwarding state and not pruned
Fa0/15 1,10,20

On switch A:
SwitchA#show int tru

Port Mode Encapsulation Status Native vlan
Fa0/2 desirable 802.1q trunking 1

Port Vlans allowed on trunk
Fa0/2 1-4094

Port Vlans allowed and active in management domain
Fa0/2 1,10,15,20

Port Vlans in spanning tree forwarding state and not pruned
Fa0/2 1,10,20

However the following syslog message gets printed to the console every minute (provided CDP is enabled):

00:14:19: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/15 (2), with SwitchA FastEthernet0/2 (1).