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PCEP Procedures and Protocol Extensions for Using PCE as a Central Controller (PCECC) for Segment Routing (SR) MPLS Segment Identifier (SID) Allocation and Distribution.

Document Type Replaced Internet-Draft (pce WG)
Expired & archived
Authors Zhenbin Li , Shuping Peng , Mahendra Singh Negi , Quintin Zhao , Chao Zhou
Last updated 2020-12-14 (Latest revision 2020-11-25)
Replaced by draft-ietf-pce-pcep-extension-pce-controller-sr
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Additional resources Mailing list discussion
Stream WG state Adopted by a WG
Document shepherd (None)
IESG IESG state Replaced by draft-ietf-pce-pcep-extension-pce-controller-sr
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


The Path Computation Element (PCE) is a core component of Software- Defined Networking (SDN) systems. It can compute optimal paths for traffic across a network and can also update the paths to reflect changes in the network or traffic demands. PCE was developed to derive paths for MPLS Label Switched Paths (LSPs), which are supplied to the head end of the LSP using the Path Computation Element Communication Protocol (PCEP). But SDN has a broader applicability than signaled (G)MPLS traffic-engineered (TE) networks, and the PCE may be used to determine paths in a range of use cases. PCEP has been proposed as a control protocol for use in these environments to allow the PCE to be fully enabled as a central controller. 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 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 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 is further enhanced for SR SID (Segment Identifier) allocation and distribution.


Zhenbin Li
Shuping Peng
Mahendra Singh Negi
Quintin Zhao
Chao Zhou

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)