L2TPv3

[nviturat20]

Hi,

I've got a network with 3 routers ISR (2811) and I would like to set up an extended LAN between them using L2TPv3 encapsulation.

So what I am planning to do it's to set up a network like below :

R1 ----(L2TPv3)----R2-----(L2TPv3)-----R3

I made the configuration between R1 and R2 using L2TPv3 and it works fine.

R1 configuration:

*****************

pseudowire-class Test

encapsulation l2tpv3

sequencing both

ip local interface loopback 1

interface loopback 1

ip address 131.10.3.1 255.255.255.0

interface vlan 102

no ip address

xconnect 131.10.15.1 1 pw-class Test

R2 configuration:

*****************

pseudowire-class Test

encapsulation l2tpv3

sequencing both

ip local interface loopback 1

interface loopback 1

ip address 131.10.15.1 255.255.255.0

interface vlan 102

no ip address

xconnect 131.10.3.1 1 pw-class Test

So now, I would like to include R3. My problem is I can't set up two xconnect on the same interface (interface vlan 102).

Is there a way to make the junction between the xconnect going to R1 and the xconnect to R3 from the router R2.

Best Regards,

Nicolas

[Giuseppe Larosa · Accepted solution]

Hello Nicolas,

if your objective is to extend the vlan on R1, R2 and R3 you need two pseudowire because they are point to point.

But this is not enough the two pseudowire endpoints on R2 have to be made to communicate:

you can use a lan switch, two different interfaces on R2 or a l2 trunk carrying two vlans on the lan switch you need two ports one in vlan x=102 and one in vlany=103 representing the second pseudowire connected by a crossover cable and to avoid to have the link blocked by STP you need to use stp bpdu filter on both ports and the ports need to be access ports one in vlanx and one in vlany.

Be aware that this can be inefficient and you can have broadcast and multicast frames replicated on the two pseudowires.

if the lan switch were a C6500 you can use intervlan bridging without the external cable.

However, I don't recommend a setup like this for a production network for the possible issues of replications of broadcast multicast frames.

Hope to help

Giuseppe

[nviturat20]

Hi Giuseppe

Thank you for your reply. It has been really helpfull. I will try your solution and let you know.

Best Regards,

Nicolas

[nviturat20]

Thanks Giuseppe,

It works well.

Best Regards,

Nicolas