Redundancy For IP VPN

[kanwaljeet]

Customer hub site has two CE routers with two links connected to two seperate PE routers in the Carrier's MPLS network. At the customer's remote site two CE router with two links are connected to PE router in MPLS network.

How can I configure the CE routers at the hub site to advertise the same network across the MPLS network to both the CE router at the remote site? Also, how can I configure the CE router at the remote site to select one of the router as the primary and the other as secondary?

the objective is to have redundancy at the hub as well as at the spoke.No load balancing is needed.

There are around 50 sites and infact customer needs any to any communication.

One of my friends suggested me to use ospf on the CE routers and BGP between CE and PE but i am not sure how this is going to help me.

Any help will be appreciated.

Thanks

KS

[Harold Ritter]

Even if you advertise the same network from both hub CE router only one will be selected by the core (PE or RR) as the best path and propagated to the remote hub CE. This is fine since all you want is redundancy and not loadsharing. If one of the hub CEs goes down traffic will converge to the other.

For loadsharing it is a little more complex cause you want the remote PEs to receive the two paths from the two hub PEs. If you use route reflectors in the core, which most SP do, this won't be possible unless you use different route distinguishers on the two PEs connected to the hub CEs. This way the RR considers the VPNv4 routes from the two PE routers to be different and propagates them to the remote PEs.

Hope this helps,

[romccallum]

Harry,

Will configuring maximum-path ibgp 2 import 2 not help? I think you can configure this on the rrs also - possibly wrong here as I have just lost my 2 rrs in the lab for a few days so cant try it.

[Harold Ritter]

Unfortunately, maximum-path would not help since, even though this features would cause the RR to install more than one BGP path in the RIB, it still only advertise the best path to the route reflector clients.

Using different RDs though would cause the RR to pass the multiple paths to the RRCs since the RR would itself considers these paths as being for different VPNv4 prefixes.

Regards,