PCEP Procedures and Protocol Extensions for Using PCE as a Central Controller (PCECC) for Segment Routing (SR) MPLS Segment Identifier (SID) Allocation and Distribution.
draft-ietf-pce-pcep-extension-pce-controller-sr-01
PCE Working Group Z. Li
Internet-Draft S. Peng
Intended status: Standards Track Huawei Technologies
Expires: August 25, 2021 M. Negi
RtBrick Inc
Q. Zhao
Etheric Networks
C. Zhou
HPE
February 21, 2021
PCEP Procedures and Protocol Extensions for Using PCE as a Central
Controller (PCECC) for Segment Routing (SR) MPLS Segment Identifier
(SID) Allocation and Distribution.
draft-ietf-pce-pcep-extension-pce-controller-sr-01
Abstract
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-MPLS SID (Segment
Identifier) allocation and distribution.
Li, et al. Expires August 25, 2021 [Page 1]
Internet-Draft PCECC-SR February 2021
Status of This Memo
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This Internet-Draft will expire on August 25, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. PCECC SR-MPLS . . . . . . . . . . . . . . . . . . . . . . . . 5
4. PCEP Requirements . . . . . . . . . . . . . . . . . . . . . . 6
5. Procedures for Using the PCE as a Central Controller (PCECC)
in Segment Routing . . . . . . . . . . . . . . . . . . . . . 7
5.1. Stateful PCE Model . . . . . . . . . . . . . . . . . . . 7
5.2. New LSP Functions . . . . . . . . . . . . . . . . . . . . 7
5.3. PCECC Capability Advertisement . . . . . . . . . . . . . 7
5.4. PCEP session IP address and TED Router ID . . . . . . . . 8
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