METHOD AND SYSTEM FOR ESTABLISHING, GRAFTING AND CUTTING BIDIRECTIONAL POINT-TO-MULTIPOINT LABEL SWITCHED PATH

摘要

Method and system for establishing a bidirectional point-to-multipoint (P2MP) label switched path (LSP). The method comprises: starting from a root node, a path message carrying an upstream label for use as an upstream path is sent by successive nodes to downstream nodes; each node creates and maintains an upstream label forwarding table for the bidirectional P2MP LSP; when a leaf node receives a path message, the leaf node returns by successive nodes to each upstream node that has forwarded the path message to said leaf node a Resv message carrying a generic label for use as a downstream path; each node creates and maintains a downstream label forwarding table for the bidirectional P2MP LSP; the nodes that the upstream path and the downstream path of the bidirectional P2MP LSP pass through are identical. Also disclosed are corresponding methods for grafting and cutting. The method allows bidirectional transmission of packets on MPLS networks along identical outward and return paths, effectively reduces the complexity of LSP management and enables transmission over MPLS networks of IEEE 1588v2 clock synchronization packets.