Layer 2 over layer 3

[Patrick McHenry]

Hi,

I know that it is possible to transport a layer 2 VLAN across a layer 3 connection but, every example I find, the CE routers on either side of the WAN share the same VLAN on there connecting interface. I want the VLAN to traverse the WAN but, at the same time. I want to have a layer 3 connection between the CE routers and have the VLAN be a totally different subnet from the layer 3 connections. Is this possible? With a GRE tunnel?

I attached a very crude diagram and I apologize for it. In the design VLAN A crosses the WAN along with the layer 3 traffic.The LANs will be totlly different subnets from each other.

Thank you, Pat.

[kcnajaf]

HI Pat,

I hope L2TPv3 is the solution which will fit for your requirement.

Please use below link for the configuration part.

http://www.networkstudies.co.uk/2011/11/extend-your-lan-across-multiple-sites.html

More details on L2TPv3 can be found on below link

http://www.cisco.com/en/US/docs/ios-xml/ios/wan_lserv/configuration/xe-3s/asr1000/wan-l2-tun-pro-v3-xe.pdf

Hope that helps

Regards

Najaf

Please rate when applicable or helpful !!!

[Patrick McHenry]

Thanks for the docs Najaf!

I've read throught them a bit and I'm not sure if the solutions described would fit. I think this design doc shows more of what I want to accomplish.

Does this make my requirements any more clear? Don't get confused by the red loops around the Campus LAN and Remote LAN. I should have used a different color as to seperate the Layer 2 network and the layer 3 network.

Thank you, Pat.

[kcnajaf]

Hi Pat,

The way i understood this is, you want to extend you LAN over the WAN. You can create a L2TPv3 tunnel between two CE routers and over this tunnel you can extend your LAN,

You could probably try this on GNS3 and verify if this fit your requirements.

Hope that helps

Regards

Najaf

Please rate when applicable or helpful !!!

[Patrick McHenry]

Thank you for the response, Najaf

Do you understand what I am trying to do?

I want to be able to carry the layer 2 VLAN inside the layer 3 traffic and split the traffic off at the one CE router - have the VLAN go to one interface and the Remote site LAN on a different interface. I want to accomplish this using one router and one WAN circuit.

Thank you, Pat.