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New Member

Q-in-Q and Bridge Groups

I am trying to connect a router to a network that has double tagged ethernet (IP) packets. I have configured an ethernet subinterface to a bridge group and to the router via a BVI (see below). Double tagged packets are received from the network to the BVI but when a response is sent, it only has the outer tag and is ultimately dropped by the network.  If I change the setup to use single tags it all works, or if I change the setup to an IP addressed subinterface, not going through the bridge group it works. I cannot find documentation on such a setup using double tag termination and bridge/BVI. Does IOS support this combination?

interface FastEthernet0/1.1

encapsulation dot1Q 3001 second-dot1q 30
bridge-group 1

interface BVI1

ip address




Hall of Fame Super Silver

Re: Q-in-Q and Bridge Groups

Hello Keith,

what is the router platform and what IOS image is running on it?

some platforms support double vlan tag termination see like 10000

Hope to help


New Member

Re: Q-in-Q and Bridge Groups

In my lab the equipment is  a Cisco IOS Software, 2800 Software with Version 12.4(24)T

In the large lab (same equipment as field), the issue is seen on a 7206 VXR also with 12.4.

In both cases, if the bridge group is removed and q-in-q terminates at the layer 3 interface (the GigE), it works fine. When the bridge group is added and the layer 3 is provided by the BVI, the problem occurs.

Thanks for your help.

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