Distinguish a link from a node failure using RSVP Hellos extensions
Jean-Philippe Vasseur
The aim of this draft is to provide a method to distinguish a link from a node failure using RSVP hello extensions. In a network making use of MPLS Traffic Engineering Fast Reroute as specified in [FAST-REROUTE], efficient use can be made of the network links when protecting against link/node failures. As described in [FACILITY], excess capacity used for bypass tunnels can be shared between bypass tunnels providing protection for mutually exclusive failures of different links or nodes. This results in significant bandwidth savings under the single failure assumption. Making use of the single failure assumption implies the need to distinguish a link from a node failure. However, the mechanisms currently available for failures detection do not always allow to distinguishing a link from a node failure.