An Architecture for Use of PCE and the PCE Communication Protocol (PCEP) in a Network with Central Control
RFC 8283
Internet Engineering Task Force (IETF) A. Farrel, Ed.
Request for Comments: 8283 Juniper Networks
Category: Informational Q. Zhao, Ed.
ISSN: 2070-1721 R. Li
Huawei Technologies
C. Zhou
Cisco Systems
December 2017
An Architecture for Use of PCE and the PCE Communication Protocol (PCEP)
in a Network with Central Control
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).
SDN has a broader applicability than signaled MPLS traffic-engineered
(TE) networks, and the PCE may be used to determine paths in a range
of use cases including static LSPs, segment routing, Service Function
Chaining (SFC), and most forms of a routed or switched network. It
is, therefore, 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.
This document briefly introduces the architecture for PCE as a
central controller, examines the motivations and applicability for
PCEP as a control protocol in this environment, and introduces the
implications for the protocol. A PCE-based central controller can
simplify the processing of a distributed control plane by blending it
with elements of SDN and without necessarily completely replacing it.
This document does not describe use cases in detail and does not
define protocol extensions: that work is left for other documents.
Farrel, et al. Informational [Page 1]
RFC 8283 PCE-CC Architecture December 2017
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8283.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Farrel, et al. Informational [Page 2]
RFC 8283 PCE-CC Architecture December 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Resilience and Scaling . . . . . . . . . . . . . . . . . 8
2.1.1. Partitioned Network . . . . . . . . . . . . . . . . . 9
2.1.2. Multiple Parallel Controllers . . . . . . . . . . . . 10
2.1.3. Hierarchical Controllers . . . . . . . . . . . . . . 12
3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1. Technology-Oriented Applicability . . . . . . . . . . . . 14
3.1.1. Applicability to Control-Plane Operated Networks . . 14
3.1.2. Static LSPs in MPLS . . . . . . . . . . . . . . . . . 14
3.1.3. MPLS Multicast . . . . . . . . . . . . . . . . . . . 15
3.1.4. Transport SDN . . . . . . . . . . . . . . . . . . . . 15
3.1.5. Segment Routing . . . . . . . . . . . . . . . . . . . 15
3.1.6. Service Function Chaining . . . . . . . . . . . . . . 16
3.2. High-Level Applicability . . . . . . . . . . . . . . . . 16
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