Extend L2 VLANs across multiple WAN sites

[Ronit Bhattacharjee]

Hello,

I have multiple sites connected via a provider's MPLS network, everything is working as expected, have full L3 connectivity across all these sites.

I now need to establish Layer 2 connectivity (One Vlan) across 21 sites. Ideally, I would plan to attach additional routers behind the CE routers (Have no access to provider CEs or PEs, but provider can re-configure BGP on the CE to peer with our device) and use a port on these routers as the Lan Layer 2 port, but not sure which technology to use

1. L2TPv3 comes to mind, but can L2TPv3 work in a multipoint setup? I can have one site as a hub and others as spokes and speak via the hub? Using traditional L2TPV3 config, how can I use multiple Xconnects for the same VLAN on the same interface?
2. Worst case scenario, I can run VPLS over MPLS (Have our new routers as VPLS PEs), but seems overkill.

What do you guys suggest is the easiest/most elegant solution for this conundrum?

[Philip D'Ath · Accepted solution]

L2TPv3 does not support multipoint.  It can only run point to point.

VPLS does support multipoint, but you need much more expensive kit to do this.

I have just a brainwave!!!  Are you only using the IP protocol for this layer 2 network?  If so, use LISP.  It runs on even the lowest end Cisco kit.  I would convert your entire network to it.

In particular, you need to enable LISP mobility.

General LISP info:

http://lisp.cisco.com/

An example of a complex DC to DC layer 2 extension using LISP with full redundancy.  You wont want something this complex, but it demonstrates what you want to do, and the massive power that LISP has.

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Data_Center/DCI/5-0/LISPmobility/DCI_LISP_Host_Mobility/LISPmobile_4.html

[e.ciollaro · Accepted solution]

HI,

as far as I know OTV tunnel support layer2 and multipoint but I never configured it. It is supported just on Nexus, ASR 1000 and ISR 4451-x

Here some useful link:

http://www.cisco.com/c/en/us/products/collateral/switches/nexus-7000-series-switches/qa_c67-574969.html

http://blog.ine.com/2012/08/17/otv-decoded-a-fancy-gre-tunnel/

https://supportforums.cisco.com/document/127411/understanding-overlay-transport-virtualization-otv

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/wan_otv/configuration/xe-3s/wan-otv-xe-3s-book/wan-otv-confg.html

Bye,

enrico.

[Ronit Bhattacharjee]

Thank you both for your replies. Turns out notifications from this forum were going to the wrong email. Both these solutions are valid, but we ended up changing the applications and removed the dependence on L2.