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New Member

InterVLAN Routing problem


I am trying to configure interVLAN routing in my 2621XM router. The router has two fastEthernet interface and I am using dot1q encapsulation as my VLAN switch is 2950 serise.

The router IOS version is 12.2(8)10T.

Now when ever I am trying to issue <encapsulation dot1q 1 native> command from subinterface mode, I am getting unrecognise command. I tried a lot. And Now I am feeling that this device does not have this command. But in data sheet of this router it is clearly written that 2621XM Router can do InterVLAN routing with dot1q and ISL encapsulation. Then why I am getting this error.

I need to fixed this problem ASAP. I am not in position to buy any other device. What ever I do, I have to do with this two device (2621XM and 2950).

I need help.


VIP Purple

Re: InterVLAN Routing problem


stupid question maybe, but do you have an IP Plus feature pack ? Can you post the output of the ´show version´ command ?



New Member

Re: InterVLAN Routing problem

Check out the link below. Also, make sure you are running the minimum IOS feature set.

Re: InterVLAN Routing problem

Ok, first you definitely have to have at least the IP Plus feature pack.

Second, you have to use sub-interfaces, like this:

interface FastEthernet0/0

no ip address

speed 100



interface FastEthernet0/0.1

encapsulation dot1Q 1 native

ip address


interface FastEthernet0/0.2

encapsulation dot1Q 2

ip address

Note that the subinterface number can be anything, I prefer to keep it equal to the VLAN number though. The VLAN is defined on the "encapsulation dot1Q " line...

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