OSPF-Based Fast Reroute for BGP Link Failures

The Border Gateway Protocol (BGP) is one of the key components of today´s Internet infrastructure. Many ISPs rely on BGP for convergence of inter-domain routes upon BGP link failures. However, the convergence of BGP requires several seconds of downtime, which may cause critical performance degradation of applications. In this paper, we propose the use of an intra-domain routing protocol to provide IP fast reroute for BGP link failures. The proposed scheme extends OSPF to restore the nexthop IP address associated with the BGP link failure. Since the reachability of the nexthop is restored at the IGP layer, no convergence is required at the BGP layer. We also introduce a recursive lookup mechanism for forwarding of packets to achieve fast update of the forwarding table. Evaluation using a prototype and real BGP prefixes observed in the Internet showed that the proposed scheme is capable of reducing the current recovery time by 13.40 seconds. The proposed scheme performs recovery with limited routers and is effective where Route Reflectors are in place.