Unable to configure trunk port in Catalyst 6513 to use dot1q encapsulation

[peter.tan]

I'm unable to configure trunk port gi2/1 (WS-X6548-GE-45AF) to use the dot1q encapsulation.

The screen shot is as follows:

interface GigabitEthernet2/1

switchport

switchport mode trunk

no ip address

shutdown

end

XAP-SF2-DC1(config-if)#switchport trunk ?

allowed

native

pruning

The encapsulation option is not available.

[Edison Ortiz]

The reason is not available is due to dot1q being the only trunking option. Dot1q is shown as an option when you can also configure isl on the interface.

You can verify you are running dot1q trunking by typing show interface g2/1 switchport