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Layer 2 transport over MAN link


I wouldlike to transport some Vlans (4-5) between two Catalyst 3750 across a MAN Ethernet Link.

We used QinQ tunneling but the provider doesn't support double tagging.

I looked on Cisco documentation that is it possbile to do a L2TP tunnel with IRB to extend Vlan on a L3 link.

My 3750 have a firmware in 12.2(44r)SE8 and they don't have the command "bridge irb".

Have you got a solution to help me, please?



Peter Paluch
Hall of Fame Cisco Employee

Hello Franck,

Unfortunately, your 3750 won't allow you to create a L2TP tunnel. In addition, the bridge irb command is used for different purposes and should not be related to L2TP. I am afraid that the 3750 has no features that would help you solve your issue. L2TP is supported only on routers, to my best knowledge (somebody correct me here if I'm wrong).

Have you actually asked your provider if he can provide a L2TP service between your sites? Or perhaps, can he provide any other service that would allow you to extend the VLANs between your sites? Don't ask specifically about Q-in-Q, just ask if the provider has any service to meet this requirement. Let's see if he can come up with some solution.

Best regards,


Thanks for your answer Peter.

I looked in an old post on this site and in the previous IOS, it was possible to use a GRE tunnel and bridge-IRB to extend à layer 2 LAN accros a L3 connection.

On my 3750, I wouldlike to know if there is a command how replace bridge-IRB.



Hello Franck,

ask to the provider to increase the MTU of the link and to make it a layer 2 service that supports tagged traffic (port based EoMPLS for example) and then you will be able to use QinQ configured on your devices,

GRE tunnels on low end multilayer switches are processed in software so their use is not recommended.

Also fallback bridging in low end multilayer switches is limited to non IPv4 traffic for legacy protocols so it is not really useful. C6500 supports bridging of IPv4 traffic in fallback bridging.

If the above is not possible you should deploy two ISR routers with appropriate feature set to support L2TPv3 vlan based.

This is valid if the amount of traffic to be extended is not big. (few Mbps not Gbps scale)


Hope to help


Thanks Giuseppe,

I already ask to our provider to increase the MTU to use QinQ and they answer, that their equipements don't support double tag.

That's why, we wouldlike to use another technology to extend our LAN overs the MAN link.