ZTE Corporation ZTE Corporation ZTE Corporation Segment Routing (SR) allows for a flexible definition of end-to-end paths within IGP topologies by encoding paths as sequences of topological sub-paths, called "segments". These segments are advertised by the link-state routing protocols (IS-IS and OSPF). And a segment is identified by a Segment Routing ID (SID). This document proposes a method to calculate SID forwarding entry within SR topology in a SR domain, and to guarantee the consistency of SR encapsulation forwarding.