Encapsulation mode Router-on-a-stick

Unanswered Question
Nov 16th, 2008

I want to use router-on-a-stick method on cisco 2600 , after creating a sub-interface, can not use "encapsulation" command to define encapsulation method and it's vlan .

How to correct this that can use "encapsulation" command ?

The IOS version is 12.2(3) .

I have this problem too.
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royalblues Sun, 11/16/2008 - 23:03

12.2 should support router on a stick

What is the exact error you are getting? can we have a look at the configuration


Davy Ad Mon, 11/17/2008 - 01:57

hi Reza,

after sub interface


Router (config-subif)# encapsula dot1q (X)-> This should be the VLAN name or Number

Then Ip address

Reza Rezazadeh Mon, 11/17/2008 - 02:10

hi alex

look at the picture attach to this post carefully.

after log in to subinterface , I type e?

only command that display is "exit" .

may be the IOS don't identify "encapsulation" command.

Best regards

Jon Marshall Mon, 11/17/2008 - 02:21


As per Mohamed's post you need to use Feature Navigator. For your version of IOS you need a minimum feature set of IP Plus to support 802.1q encapsulation.

If the command is not available then i suspect your feature set is just IP.


Davy Ad Mon, 11/17/2008 - 02:28


could you let us know what IOS are you using and also try to write the Encapsulation in full text okay



Reza Rezazadeh Mon, 11/17/2008 - 02:59


I was test this by the original IOS of my router "c2600-i-mz.122-2.T1.bin" but can't do this and upgrade the IOS to "c2600-io3-mz[1].122-3" , but also can't. I thik that the IOS don't supprt this feature after test with Cisco Feature Navigator.

I was write the command completely but can't.

Jon Marshall Mon, 11/17/2008 - 04:07


You are using IP/FW/IDS feature set. This does not support 802.1q encapsulation. If you want to use 802.1q you will need to change the feature set of your IOS. You can still use 12.2(3) but IP Plus is the minimum to support 802.1q - image file name is c2600-is-mz.122-3.bin.

But you also need to check if you are losing any features by changing the feature set. For a start is there a reason you are running the FW/IDS feature set ie. are you using the firewalling or IDS features ?

This is why using Feature Navigator as suggested by Mohamed is what you need to do.



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