Native Vlan and around

[lformelli]

I have connected two Catalysts 3550 in trunk with Extended IOS.

On both my customer has wanted to put in shut Vlan 1 and configure Vlan 2 with ip address.

From this switch I connected , through ge port , another Catalyst 3550 which is working for two weeks.

This connection hasn't to work on trunk but with port configured in access mode on Vlan 2.

Just I connected the remote switch I had two things.

1)The new link become trunk

2)On consolle arose messages :%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on Gigabi

tEthernet0/2 (2), with BO_1_Piano GigabitEthernet0/1 (1).

What's happen ?

Should I put in access mode the port peer and put in shut int vlan1on remote switch also?

thanks

Lorenzo

[steve.barlow]

In native IOS, the native VLAN can be changed by issuing the "switchport trunk native vlan 2" interface command which is configured on the trunk port. Enter that command on the interface on both switches.

Hope it helps.

Steve

[schm196]

Agree with the previous poster; also, make sure you understand which trunking protocol you are using. Cisco's proprietary ISL changes frames and automatically finds the native VLAN. The industry standard 802.1q, however, encapsulates frames and requires a single VLAN to be not encapsulated to carry the control traffic, which is the native VLAN, usually your management VLAN. If you change the native VLAN to anything but VLAN1 you must configure the same native VLAN on both ends or it won't work. Good luck!