RFC 9689 · INFORMATIONAL · 2024

Use Cases for a PCE as a Central Controller

Overview

RFC 9689, “Use Cases for a PCE as a Central Controller”, is an Informational document published in December 2024 by Z. Li, D. Dhody, Q. Zhao, Z. Ke, B. Khasanov. The canonical text is published by the RFC Editor.

Abstract

The PCE is a core component of a Software-Defined Networking (SDN) system. It can be used to compute optimal paths for network traffic and update existing paths to reflect changes in the network or traffic demands. The PCE was developed to derive Traffic Engineering (TE) paths in MPLS networks, which are supplied to the headend of the paths using the Path Computation Element Communication Protocol (PCEP).

SDN has much broader applicability than signalled MPLS TE networks, and the PCE may be used to determine paths in a range of use cases including static Label-Switched Paths (LSPs), Segment Routing (SR), Service Function Chaining (SFC), and most forms of a routed or switched network. Therefore, it is reasonable to consider PCEP as a control protocol for use in these environments to allow the PCE to be fully enabled as a central controller.

A PCE as a Central Controller (PCECC) can simplify the processing of a distributed control plane by blending it with elements of SDN without necessarily completely replacing it. This document describes general considerations for PCECC deployment and examines its applicability and benefits, as well as its challenges and limitations, through a number of use cases. PCEP extensions, which are required for the PCECC use cases, are covered in separate documents.

Abstract as published in the RFC, via rfc-editor.org.

What “Informational” means

Published for the general information of the community. It does not define an IETF standard and carries no standards-track status.

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