Help with policy routing

[justin.allen]

Can somebody tell me if you can have redundancy with policy routing. I have a site one circuit is MPLS the other is a vpn connection via a DSL line. I want to have video go over the DSL and just critical applications go over the MPLS. To do this I would use Policy routing. But if the DSL fails I want to route over the MPLS. Is there anyway to do this. Any help would be good. I am beating my head against the desk trying to figure this out.

[attrgautam]

When you set the next hop in your route-map, you can set multiple next-hops, if the first IP is down, it will prefer the 2nd. This will work only with Serial Links as Ethernet may not go down

[justin.allen]

Hmmm, I see the delima here. If my DSL router never goes down I will never know it failed. I would like to use the DSL as a primary for Non-critical traffic and have it move to MPLs if it fials. So I guess that would not work right? Any other ideas?

[Richard Burts]

Justin

In general Policy Based Routing does provide a certain level of redundancy in that when you configure PBR you are providing an over-ride to the normal routing logic. If the specified next-hop (or whatever you have set) in the PBR is not available then the packet is handled by the normal routing logic not the over-ride.

This is especially easy on things like serial interfaces where the interface will go protocol down. It is more of a challenge on interfaces like Ethernet where there may be no connectivity but the interface is still up/up. In recent versions of IOS Cisco has introduced an enhancement called Enhanced Object Tracking. You can use this feature in conjunction with PBR which should allow you to detect if there has been a problem with the DSL and fail traffic over to the MPLS.

HTH

Rick

[justin.allen]

Yeah, I found this great Article. This is just and FYI in case somebody runs into the same problem I did. If you click on the more senerios at the bottom of this web page it has a great article on Policy routeing and object tracking. Thanks for everybody help.

http://www.cisco.com/en/US/about/ac123/ac114/ac173/Q2-04/department_techtips.html