connecting 2 MPLS networks together

tweller · ‎07-05-2007

Need some advice on connecting 2 MPLS networks together from two different ISPs. The compnay I am working with is using AT&T MPLS and they aquired a smaller company using SBC MPLS. We want to connect the two networks together for the shorterm and eventually the goal would be to add te new sites to the AT&T MPLS.

swaroop.potdar · ‎07-05-2007

You have two options here,

1) you can talk to you SP regarding the situation and they should be able to put across a inter-AS solution for you, and this should be possible looking at the close ties between ATnT and SBC.

2) If you plan to go ahead with this on your own, since its only a transitionary situation, you can think of interconnecting both the networks core at the closest possible location terming them as border gateway routers. And then keep migrating the smaller companies sites to the your existing SP's network.

But do note that if there are overlapping IP addresses between both the networks then you may have to consider a NAT gateway in addition to the border gw routers. If you plan to use the Inter-as option, the SP would have a NAT gw solution for the same.

Overall you need a crystal clear plan before you go ahead with any of the options.

HTH-Cheers,

Swaroop

tweller · ‎07-05-2007

If we handle this ourselves and connect both Corp offices with lets say a T1 and two Cisco routers, what routing protocol would you suggest?

swaroop.potdar · ‎07-05-2007

What are the routing protocols you have on either sides.

Mutual redistibution should be good, to keep things simple. And since its a single point redistribution it should be a problem as well.

HTH-Cheers,

Swaroop

tweller · ‎07-05-2007

The sample coonfig I have been looking at is using eBGP between ASBR's. Am I going down the wrong path?

http://www.cisco.com/warp/public/105/interasvpn.html

swaroop.potdar · ‎07-05-2007

This document is for service providers who want to provide Inter-As services for their end clients.

Since you are already an end client you can go to your SP for such a service.

As you want to do it on your own and its only a transitionary situation, you can redistrbute between the IGP of both sides and have 2 way reacability achieved for your migration.

HTH-Cheers,

Swaroop