This Recommendation provides requirements and mechanisms for 1+1, 1:1, shared mesh, and packet 1+1 protection switching functionality for the user-plane in MPLS layer networks. The mechanism defined herein is designed to support end-to-end point-to-point LSPs. Protection switching functionality for multipoint-to-point and point-to-multipoint LSP are for further study. m:n protection switching is for further study. Hitless protection switching is outside the scope of this version of the Recommendation