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dot1q encapsulation on 1721 router

Does anyone know if there is a way to enable dot1q encapsulation on two ethernet ports on a 1721 router.  I am able to configure it on the built in fastethernet port, but not on any interface provided by a WIC-1ENET or a WIC-4ESW.  I have an application that requires two physical ethernet ports that support dot1q encapsulation.

4 REPLIES
Hall of Fame Super Silver

dot1q encapsulation on 1721 router

David

I know that dot1q encapsulation is not supported on the 10 M Ethernet interface. I would have thought that one of the switch ports would be capable, but I certainly do not know that for a fact. And if you have tried it and it did not work then perhaps it is not supported.

HTH

Rick

Bronze

Re: dot1q encapsulation on 1721 router

David

Rick is right, you need a fastethernet interface to use do1q.

Just for curiosity can you post an output of "show interfaces" command?

Just another thought. Why don't you use subinterfaces on the fastethernet? It will act like to separate interfaces with their own subnets.

Eugen

Hall of Fame Super Gold

dot1q encapsulation on 1721 router

I know that dot1q encapsulation is not supported on the 10 M Ethernet interface.

Yes, that was the impression I get until someone, I think it was Rob "Smooth Rob" Huffman pointed out that Cisco released an IOS to allow the 2600 ethernet router to support 802.1Q.  I believe, if I'm not mistaken, the "T" train will enable this feature.

I'm trying to look for this particular post because he specifically mentioned the IOS.

Hall of Fame Super Gold

dot1q encapsulation on 1721 router

802.1Q Encapsulation Support on Cisco 2600/3600 Series Routers

802.1Q encapsulation is now available on the built-in 10BaseT Ethernet interfaces of the Cisco 2610, 2611, and 2612 with Cisco IOS software 12.2(2)T and subsequent releases. Although this feature has been available on the Cisco 2600/3600 series since the release of Cisco IOS 12.1(5)T, support was previously limited to Fast Ethernet interfaces only. 802.1Q is not supported on any other Cisco 2600/3600 series 10BaseT Ethernet interface.

I know this document is for the 2600/3600 router with Ethernet interface, however, I am not certain how "up-to-date" this document is, particular the last sentence.

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