P2MP path computation and operation in MPLS and optical networks

In this presentation, we discuss an application of PCE-based operation of point-to-multipoint (P2MP) label switched paths (LSP) in MPLS and optical networks. Path computation for P2MP traffic-engineered (TE) LSPs presents a significant challenge because of the complexity of the computation. Determining disjoint protection paths for P2MP TE LSPs can add considerably to this complexity, while small modifications to a P2MP tree (such as adding or removing just one leaf) can completely change the optimal path. Reoptimization of a network containing multiple P2MP TE LSPs requires considerable computational resources. All of this means an ingress label switched router (LSR) may not have sufficient processing power to perform the necessary computations, and even if it does, the act of path computation might interfere with the control and management plane operation necessary to maintain existing LSPs. We will summarise the latest IETF work, which facilitates offloading such path computations from LSRs to a dedicated network resource capable of computing constrained P2MP paths using a PCE-based architecture