Method And Apparatus For Segment Routing And RSVP-TE Routing In Transport SDN Networks

A method for routing packet traffic through a network comprising a plurality of network nodes supporting RSVP-TE protocol and Segment Routing protocol. Each of the two protocols is associated with a separate set of labels, the method comprises calculating (202) a path through the network; checking support (204) for both protocols at nodes along the calculated path and encoding (206) the calculated path as a set of Adjacency Segment Identifiers. The method also comprises optimising (208) a label stack of the calculated path by substituting more than one adjacency SIDs with a node SID if a partial path identified by the substituted adjacency SIDs equals a shortest path. If all nodes along the calculated path support label stack depth equal to or deeper than the optimised label stack (210) then segment routing is used to set up the path. If a node along the calculated path does not support a label stack depth equal to or deeper than the depth of the optimised label stack (210) then an Explicit Route Object is used for signalling the calculated path using RSVP-TE (214).