Design recommendations for Dual BGP MPLS network

bgibson · ‎06-27-2007

I am trying to come up with a way to properly implement a dual MPLS to the branch network. I would like to use both networks simultaneously. Most of my traffic goes from the head ends to the branches.

Most branches have 2 networks. A voice network and a data network. What I am thinking of doing is advertising 1 network to each MPLS cloud and conditionally advertising the other network in the case of a network outage. This should allow me to utilized both networks.

Does this seem like a good idea? Would enhanced object tracking be a better way of doing that? Can you use EOT with BGP advertisements? Can anyone think of a better way to utilize both networks at the same time?

Attached is a basic diagram.

carenas123 · ‎07-03-2007

One advantage of dual MPLS networks vs. using an Internet option is the ability to retain end-to-end, bi-directional QoS (quality of service) markings and support. This may be difficult or impossible to achieve across random topology. Another advantage of a dual MPLS network is the need to support modern streaming and voice applications.

jkillion · ‎07-03-2007

Rather than a conditional advertisement, I would use AS prepending. Have one router advertise the data subnet w/ no prepends and the other router advertises it with 5 (and vice versa for the voice). You could also use MED if you are peering with the same provider to achieve similar results.

bgibson · ‎07-05-2007

Thanks for the suggestion. I'll have to read up on that.

The two clouds are from different providers.

mchoo2005 · ‎07-25-2007

I concur with jkillion. AS-PATH Prepending is definitely your best bet.

quistn · ‎07-24-2007

advertise both subnets out across both carriers using eBGP. Redistribute eBGP into your IGP (i use EIGRP) on your WAN edge.

out of your head-end, advertise only your needed network (I simply need to advertise a 0.0.0.0 out of the head-end for my remote locations).

Hopefully you have a L3 LAN presence; if so, you now have two equal cost paths for both subnets.