Here is the scenario. I have two routers, each router has a single WAN link but to two different providers. RouterA is connected to ProviderA and RouterB is connected to PrivderB. The providers are using BGP for their routing. I am exchanging routers to them using BGP. In RouterA I have a loopback adaptor for H.323 traffic that I need to distribute to both providers. Also I need to make sure that both routers see the head end IP subnet of 192.168.200.x. I am running EIGRP internally and BGP into the provider. I have successfully configured redistribution between BGP and EIGRP. Everything works fine on the redistribution except when a WAN link fails. When one of the circuits fails it causes me to loose connectivity to the head end router, I then loose my BGP routes from that link. It then immediately installs the EIGRP routes learned from the other router into my routing table and all connectivity remains intact. The problem is when the Serial link is back and the BGP routes a learned they do not remove the EIGRP routes and the serial link is not used because the router things it should send traffic over EIGRP to the other router. If I reset the EIGRP neighbors then the BGP route is reinserted. The BGP as an AD of 20 and the EIGRP has AD of 170 so I don’t understand why it is not removing the EIGRP route once BGP comes back online.
int this case you want to prefer the EIGRP route over the BGP route for specific IP subnets.
I will assume that the IP subnets of interest are those of the loopbacks:
192.168.200.x on router Ry
this effect can be achieved by using the network backdoor command in router bgp configuration
router bgp 65001
network 192.168.200.3 mask 255.255.255.255 backdoor
router bgp 65001
network 192.168.200.2 mask 255.255.255.255 backdoor
the result is that eBGP route for 192.168.200.x on Ry is presented on IP routing table with AD 200 and EIGRP route will be installed for its lower Administrative distance (170 worst case if D EX)
Hope to help