IETF RFC 7715 PDF

This document describes procedures to support node protection for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths (P2MP and MP2MP LSPs) that have been built by the Multipoint Label Distribution Protocol (mLDP). In order to protect a node N, the Point of Local Repair (PLR) Label Switching Router (LSR) of N must learn the Merge Point (MPT) LSR(s) of node N such that traffic can be redirected to them in case node N fails. Redirecting the traffic around the failed node N depends on existing Point-to-Point (P2P) Label Switched Paths (LSPs). The pre-established LSPs originate from the PLR LSR and terminate on the MPT LSRs while bypassing LSR N.