Layer2 connection between facilities

[s_l_9_6]

We would like to establish a site-to-site connection, enabling Layer2 traffic (especially Multicast) flowing between our two sites using two of our ASR1001-X routers.

I've already read in an other discussion that L2TPv3 should support this. Would this also be the choice of yours? VXLAN should be capable of delivering the same Layer 2 connection, but in my understanding has way more overhead. I think EoGRE isn't the right protocol for this because Multicast Traffic is not supported.

Are there any MTU problems with this solution? Fragmentation would be no problem for us, but dropped packets would be. Thanks for your help!

[Giuseppe Larosa · Accepted solution]

Hello,

L2TPv3 provides a point to point service it is not able to handle multipoint connectivity.

So if you are sure that the L2 extension is needed only between two sites in the short/medium term I would go for L2TPv3.

L2TPv3 can work in Vlan mode or port mode (the access link can be a subinterface or a physical port).

The L2TPv3 xconnect should use loopback addresses as endpoints. These addresses must be advertised in a routing protocol.

To avoid fragmentations the links between the two routers should support an increased MTU like 1600 bytes.

Fragmentation impacts performance also for devices like ASR 1001-X and it should be avoided.

You may need to pay more money to the ISP to increase the MTU on the links to the two ASR 1000 but it is a wise decision.

Hope to help

Giuseppe