Routing between branches with MPLS

[craig_bungard]

The company I work for is moving to an MPLS network. Our headquarters has fiber going to it and all of the other branches are using T1 or T3 for connection to the MPLS network through AT&T. AT&T has proved use with a CE router that they have configured but we are placing our own router behind that one at our main branch and having ASA5505 at all of our branches. I was wondering if there is a way to setup either static or dynamic routing between our routers/ASA through the AT&T provided router. We have tried to use static routes but were unable to ping the other side. 

[milan.kulik]

Hi,

the easiest way for you would be asking AT&T to configure static routes for the subnets behind your ASAs and routers.

They need to know your device IP address to configure it as the next-hop.

It would also be possible to run some dynamic protocol between AT&T routers and your devices but I guess it would be more complicated?

Best regards,

Milan

[craig_bungard]

So if I wanted to implement a dynamic routing protocol with our equipment through the MPLS, could I use a tunnel for implementing either EIGRP or OSPF?

[Nagendra Kumar Nainar]

Craig,

You can, but I dont think it is recommended unless you have a strong reason. Normally when the MPLS circuit is layer 3, you can enable any IGP (after discussing with your ISP) and enable it on both side CE devices. This way you can exchange all your networks dynamically. With this approach, you ISP will be part of your IGP domain and will learn your prefixes (in a specific VRF, so you dont want to worry abut any route leak).

If you dont need your ISP to participate in IGP, but you need your IGP adjacency with your remote neighbor over MPLS cloud (for any business reasons), you can try L2VPN service from MPLS provider.

-Nagendra