No Encapsulation command when trunking on 4507R E core

Answered Question
Jan 19th, 2009

I was doing some trunking - typical command such as switchport mode trunk then typed encapsulation dot1q and it was not available. But the dot1q-tunnel was available.

Is dot1q-tunnel one in the same for encapsulation or is this a another ios upgrade for me? I just upgraded this switch to ios version 12.2(46)SG

Correct Answer by Mark Yeates about 8 years 4 weeks ago

Pete,

With the particular module you have it only supports dot1q trunks. the "switchport trunk encapsulation dot1q" command is only valid is ISL trunking is also supported on the module. The "switchport mode trunk" command will be sufficient to form a dot1q trunk. No need to specify the form of trunk.

HTH,

Mark

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Correct Answer
Mark Yeates Mon, 01/19/2009 - 18:32

Pete,

With the particular module you have it only supports dot1q trunks. the "switchport trunk encapsulation dot1q" command is only valid is ISL trunking is also supported on the module. The "switchport mode trunk" command will be sufficient to form a dot1q trunk. No need to specify the form of trunk.

HTH,

Mark

planzone Mon, 01/19/2009 - 18:34

Chuckle - ok Mark.

Thanks as always. - Can you tell I am rusty ? :)

Sounds like I am golden.

planzone Wed, 01/21/2009 - 18:38

OK I have been away for a bit.. So just to re-confirm. If I have a switch on one end in an IDF and to trunk it I need to switchport mode trunk encapsulation dot1q on its gbic interface and on the core side I just use switchport mode trunk ?

NOT switchport mode dot1q-tunnel ??

And all should be good?

Jon Marshall Wed, 01/21/2009 - 18:56

Pete

As Mark said if the module only supports 802.1q encapsulation then the command "switchport trunk encapsulation dot1q" is not available.

So yes just use "switchport mode trunk" on the 4500 port.

Jon

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