Huawei Technologies Huawei Technologies RtBrick Inc Etheric Networks HPE The PCE is a core component of Software-Defined Networking (SDN) systems. A PCE-based Central Controller (PCECC) can simplify the processing of a distributed control plane by blending it with elements of SDN and without necessarily completely replacing it. Thus, the Label Switched Path (LSP) can be calculated/set up/initiated and the label forwarding entries can also be downloaded through a centralized PCE server to each network device along the path while leveraging the existing PCE technologies as much as possible. This document specifies the procedures and PCE Communication Protocol (PCEP) extensions when a PCE-based controller is also responsible for configuring the forwarding actions on the routers, in addition to computing the paths for packet flows in a segment routing (SR) network and telling the edge routers what instructions to attach to packets as they enter the network. PCECC as defined in RFC 9050 is further enhanced for SR-MPLS SID (Segment Identifier) allocation and distribution.