Explanation/Reference:
Explanation:
A rib-failure occurs when BGP tries to install the bestpath prefix into the RIB, but the RIB rejects the BGP route because a route with better administrative distance already exists in the routing table. An inactive Border Gateway Protocol (BGP) route is a route that is not installed in the RIB, but is installed in the BGP table as rib-failure.
Example Topology
Router 1 (R1) and router 2 (R2) have two parallel links; one links runs BGP AS 65535 and the other link runs Enhanced Interior Gateway Routing Protocol (EIGRP) AS 1. Both BGP and EIGRP are advertising the network 10.1.1.1/32 on R1.

R2 learns about the 1.1.1.1/32 route through both EIGRP and BGP, but installs only the EIGRP route in the routing table because of the lower administrative distance. Since the BGP route is not installed in the R2 routing table, the route appears as a rib-failure in the R2 BGP table. ReferencE. http://www.cisco.com/ c/en/us/support/docs/ip/border-gateway-protocol-bgp/116146- config-bgp-next-hop-00.html