Thanks for pointing that out, Jon. You're correct. I cobbled this diagram from a setup with a second router between the customer router and the upstream router which made it iBGP routes that I had to modify the AD on. You're 100% correct. In this case I shouldn't need to modify the AD for the BGP routes to be preferred over the OSPF routes. Below is the IP and BGP tables as well as the OSPF RIB from Rtr A in three circumstances. ------------------------------------------------------------------------- The primary MPLS connection is up originally: Rtr-A#sh ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP + - replicated route, % - next hop override Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 1.1.1.0/30 is directly connected, GigabitEthernet0/0 L 1.1.1.1/32 is directly connected, GigabitEthernet0/0 2.0.0.0/30 is subnetted, 1 subnets B 2.2.2.0 [100/0] via 1.1.1.2, 00:01:59 5.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 5.5.5.0/30 is directly connected, GigabitEthernet2/0 L 5.5.5.1/32 is directly connected, GigabitEthernet2/0 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 10.10.10.0/24 is directly connected, GigabitEthernet1/0 L 10.10.10.1/32 is directly connected, GigabitEthernet1/0 20.0.0.0/24 is subnetted, 1 subnets B 20.20.20.0 [100/0] via 1.1.1.2, 00:01:00 Rtr-A#sh ip bgp BGP table version is 23, local router ID is 10.10.10.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path * 1.1.1.0/30 1.1.1.2 0 0 300 i *> 0.0.0.0 0 32768 i *> 2.2.2.0/30 1.1.1.2 0 0 300 i * 5.5.5.0/30 1.1.1.2 0 300 200 ? *> 0.0.0.0 0 32768 ? *> 10.10.10.0/24 0.0.0.0 0 32768 ? *> 20.20.20.0/24 1.1.1.2 0 300 200 ? Rtr-A#sh ip ospf rib OSPF Router with ID (10.10.10.1) (Process ID 1) Base Topology (MTID 0) OSPF local RIB Codes: * - Best, > - Installed in global RIB * 5.5.5.0/30, Intra, cost 50000, area 0, Connected via 5.5.5.1, GigabitEthernet2/0 * 10.10.10.0/24, Intra, cost 1, area 0, Connected via 10.10.10.1, GigabitEthernet1/0 * 20.20.20.0/24, Intra, cost 50001, area 0 via 5.5.5.2, GigabitEthernet2/0 ---------------------------- The MPLS connection is down (failover): Rtr-A#sh ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP + - replicated route, % - next hop override Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 1.1.1.0/30 is directly connected, GigabitEthernet0/0 L 1.1.1.1/32 is directly connected, GigabitEthernet0/0 5.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 5.5.5.0/30 is directly connected, GigabitEthernet2/0 L 5.5.5.1/32 is directly connected, GigabitEthernet2/0 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 10.10.10.0/24 is directly connected, GigabitEthernet1/0 L 10.10.10.1/32 is directly connected, GigabitEthernet1/0 20.0.0.0/24 is subnetted, 1 subnets O 20.20.20.0 [110/50001] via 5.5.5.2, 00:00:07, GigabitEthernet2/0 Rtr-A#sh ip bgp BGP table version is 1, local router ID is 10.10.10.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path * 20.20.20.0/24 5.5.5.2 50001 32768 ? Rtr-A#sh ip ospf rib OSPF Router with ID (10.10.10.1) (Process ID 1) Base Topology (MTID 0) OSPF local RIB Codes: * - Best, > - Installed in global RIB * 5.5.5.0/30, Intra, cost 50000, area 0, Connected via 5.5.5.1, GigabitEthernet2/0 * 10.10.10.0/24, Intra, cost 1, area 0, Connected via 10.10.10.1, GigabitEthernet1/0 *> 20.20.20.0/24, Intra, cost 50001, area 0 via 5.5.5.2, GigabitEthernet2/0 Rtr-A# ---------------- The MPLS connection is restored (should move back to MPLS, but remains on failover): Rtr-A#sh ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP + - replicated route, % - next hop override Gateway of last resort is not set 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 1.1.1.0/30 is directly connected, GigabitEthernet0/0 L 1.1.1.1/32 is directly connected, GigabitEthernet0/0 5.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 5.5.5.0/30 is directly connected, GigabitEthernet2/0 L 5.5.5.1/32 is directly connected, GigabitEthernet2/0 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 10.10.10.0/24 is directly connected, GigabitEthernet1/0 L 10.10.10.1/32 is directly connected, GigabitEthernet1/0 20.0.0.0/24 is subnetted, 1 subnets O 20.20.20.0 [110/50001] via 5.5.5.2, 00:01:10, GigabitEthernet2/0 Network Next Hop Metric LocPrf Weight Path * 1.1.1.0/30 1.1.1.2 0 0 300 i * 0.0.0.0 0 32768 i * 2.2.2.0/30 1.1.1.2 0 0 300 i * 5.5.5.0/30 1.1.1.2 0 300 200 ? * 0.0.0.0 0 32768 ? * 10.10.10.0/24 1.1.1.2 0 300 200 ? * 0.0.0.0 0 32768 ? * 20.20.20.0/24 1.1.1.2 0 300 200 ? * 5.5.5.2 50001 32768 ?
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