Path Computation Element Communication Protocol (PCEP) Extensions for SID verification for SR-MPLS

This document defines extensions to the Path Computation Element Communication Protocol (PCEP) to support SID verification in Segment Routing MPLS (SR-MPLS) networks. Specifically, it introduces a flag in the SR-ERO subobject to indicate that the Path Computation Client (PCC) is explicitly requested to verify SID(s) by the Path Computation Element (PCE), and defines capability exchange mechanisms.