Loop-Free Alternates for IP/LDP Local Protection
Ed (Avici Systems)
This document defines an architecture and selection process for providing local protection for IP unicast and/or LDP traffic in the event of a single link or node failure until the router has converged. When computing the primary next-hop for a prefix, a router S also determines an alternate next-hop which can be used if the primary next-hop fails. The alternate next-hop is said to be a loop-free alternate, which goes to a neighbor whose shortest path to the prefix does not go back through the router S.