Cisco 1751 and 802.1q

Answered Question
Jun 1st, 2007

I have a Cisco 1751 router and trying to do interVLAN routing. However, I can't seem to define the VLAN encapsulation format as dot1q.

Everytime I enter the following command:

Router(config-if)#encapsulation dot1q 1

I get this error message:

% Invalid input detected at '^' marker.

Does my router support 802.1q? I went through the documentation and it says that it does. I am a bit new to this stuff so please bear with me.

I have this problem too.
0 votes
Correct Answer by mohammedmahmoud about 9 years 6 months ago

Hi,

The encapsulation is configured under the subinterface not the main interface:

router(config)#int fastEthernet 0/0

router(config-if)#no shut

router(config-if)#exit

router(config)#int fastEthernet 0/0.x

router(config-subif)#encapsulation dot1Q {vlan_number} [native]

router(config-subif)#ip address x.x.x.x

router(config-subif)#exit

router(config)#int fastEthernet 0/0.y

router(config-subif)#encapsulation dot1Q {vlan_number}

router(config-subif)#ip address y.y.y.y

router(config-subif)#exit

HTH, please do rate all helpful replies using the scroll box on the right,

Mohammed Mahmoud.

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Correct Answer
mohammedmahmoud Fri, 06/01/2007 - 00:42

Hi,

The encapsulation is configured under the subinterface not the main interface:

router(config)#int fastEthernet 0/0

router(config-if)#no shut

router(config-if)#exit

router(config)#int fastEthernet 0/0.x

router(config-subif)#encapsulation dot1Q {vlan_number} [native]

router(config-subif)#ip address x.x.x.x

router(config-subif)#exit

router(config)#int fastEthernet 0/0.y

router(config-subif)#encapsulation dot1Q {vlan_number}

router(config-subif)#ip address y.y.y.y

router(config-subif)#exit

HTH, please do rate all helpful replies using the scroll box on the right,

Mohammed Mahmoud.

mohammedmahmoud Sun, 06/03/2007 - 22:33

Hi,

You are very welcomed, and please do use the forum always if you have any problems doing or understanding things (and thank you for the nice rating).

BR,

Mohammed Mahmoud.

spremkumar Fri, 06/01/2007 - 00:42

Hi

Can you post the output of show version command ?

You need to have ip plus feature set to have the support for the same.

regds

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