BGP PIC Edge/Inter-AS link protection for BGP-LU

This feature introduces BGP Prefix Independent Convergence (PIC) edge protection for inter-AS link failures in a seamless MPLS architecture, where BGP Labeled Unicast (LU) is used as the MPLS transport protocol between domains. Link protection is essential in an MPLS network to ensure traffic restoration in case of an interface failure. In inter-AS link protection, the primary next hop points to the direct inter-AS link, while the backup next hop points to another direct inter-AS link or to a remote BGP-LU path. This supported functionality is similar to BGP multipath, except that only one next hop is used for active forwarding, and a second path is in protected mode.