MPLS-TE Inter-AS

[Marwan ALshawi]

Hi

just want to know how and what is the best way to route traffic over Inter-AS MPLS-TE using Option B for L2VPN and L3VPN

[amit.bhagat]

Hi Marwan,

I think it would be still "autoroute announce" (this is most common) on the headend for the tunnel configured with loose-hops. Only, in this case, the IP Addresses of ASBRs and head-end/tail-end routers would be advertised to other AS.

Regards,

Amit.

[amit.bhagat]

Sorry, my bad.....just tested this and it wont work. The reason I see is that the VPNv4 label changes at ASBRs during advertisement, but in data-plane the VPNv4 label is never changed at ASBR due to MPLS-TE transport label on top causing the remote-PE to drop traffic.

I think it would only work if PEs in different AS can exchange VPNv4 routes directly, rather than through ASBR.

Regards,

Amit.

[Marwan ALshawi]

but Cisco support MPLS-TE with inter-AS option B and I believe there should be a away to get it working !!

by the way with option B you need to have the tail-end loopback of the other AS PE to establish the TE tunnel with the loose path option, right ?

[amit.bhagat]

No need due to loose-path option, but you do need "mpls traffic-eng passive-interface" between ASBRs.

Regards,

Amit.

[Marwan ALshawi]

but i think even in the loose path you need to specify the tail-end IP/loopback

in other words the tail-end IP need to be leaked between the two ASes !, right