Recursive Resolution over BGP Multipath

This feature introduces recursive resolution over BGP multipath. When a BGP prefix that has a single protocol next hop is resolved over another BGP prefix that has multiple resolved paths (unilist), all the paths are selected for protocol next-hop resolution. Before this feature, only one of the paths was picked for protocol next-hop resolution because the resolver did not support load-balancing across all paths of the IBGP multipath route. The resolver in the routing protocol process (rpd) resolves the protocol next-hop (PNH) address into immediate forwarding next hops. The BGP recursive resolution feature enhances the resolver to resolve routes over an IBGP multipath route and use all the feasible paths as next hops. This feature benefits densely connected networks where BGP is used to establish infrastructure connectivity such as WAN networks with high ECMP and seamless MPLS topology.