Can 3845, 2821 or 7206 routers do QinQ vlan tagging on subinterfaces?

Unanswered Question
Apr 10th, 2009

We're told by a service provider that we need to implement QinQ double vlan tagging on our external interfaces, but we have the above routers connected to the provider and I don't think they support QinQ. Is that correct?

I have this problem too.
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Edison Ortiz Fri, 04/10/2009 - 09:29

That's an odd request. It's the Service Provider's responsibility to deploy QinQ in their network and your devices will be configured for 802.1q trunking which you can do on any of these routers.



jkeeffe Fri, 04/10/2009 - 09:49

That's what I thought. We were told we'd be given a clean Fastethernet hand-off and would be able to do anything we wanted on our router interfaces - that they (the ISP) would transparently pass whatever we configured.

We want to do standard L3 802.1q, for instance:


encap dot1q 10

ip address


encap dot1q 50

ip address

But the ISP is having troubles giving us a clean connection, and they came back and said that somewhere in their cloud they are triple tagging and we will need to double tag using QinQ to get it to work.

It sounds like they really don't know what's going on.

Edison Ortiz Fri, 04/10/2009 - 09:53

If it's a clean pseudowire connection (which the ISP can implement with QinQ or xconnect) then you can pass any Vlans you want.

I'm really confused what the problem really is.

It sounds like they are telling you that you can't trunk to their PE device and in order to pass 801.Q Vlans, you must be doing your own QinQ. That's odd and I hope you get a great discount :)




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