In a VPRN context, BGP fast reroute is optional and must be enabled. Fast reroute can be applied to all IPv4 prefixes, all IPv6 prefixes, all IPv4 and IPv6 prefixes, or to a specific set of IPv4 and IPv6 prefixes.
If all IP prefixes require backup path protection, use a combination of the BGP instance-level backup-path and VPRN-level enable-bgp-vpn-backup commands. The VPRN BGP backup-path command enables BGP fast reroute for all IPv4 prefixes and, or all IPv6 prefixes that have a best path through a VPRN BGP peer. The VPRN-level enable-bgp-vpn-backup command enables BGP fast reroute for all IPv4 prefixes and, or all IPv6 prefixes that have a best path through a remote PE peer.
If only some IP prefixes require backup path protection, use route policies to apply the install-backup-path action to the best paths of the IP prefixes requiring protection. See the ‟BGP Fast Reroute” section of the 7450 ESS, 7750 SR, 7950 XRS, and VSR Unicast Routing Protocols Guide for more information.