Path Computation Element Communication Protocol (PCEP) Extension for Label Switched Path (LSP) Diversity Constraint Signaling
RFC 8800

Document Type RFC - Proposed Standard (July 2020; No errata)
Authors Stephane Litkowski  , Siva Sivabalan  , Colby Barth  , Mahendra Negi 
Last updated 2020-07-28
Replaces draft-dhody-pce-of-diverse, draft-litkowski-pce-association-diversity
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Internet Engineering Task Force (IETF)                      S. Litkowski
Request for Comments: 8800                           Cisco Systems, Inc.
Category: Standards Track                                   S. Sivabalan
ISSN: 2070-1721                                        Ciena Corporation
                                                                C. Barth
                                                        Juniper Networks
                                                                 M. Negi
                                                           RtBrick India
                                                               July 2020

  Path Computation Element Communication Protocol (PCEP) Extension for
        Label Switched Path (LSP) Diversity Constraint Signaling


   This document introduces a simple mechanism to associate a group of
   Label Switched Paths (LSPs) via an extension to the Path Computation
   Element Communication Protocol (PCEP) with the purpose of computing
   diverse (disjointed) paths for those LSPs.  The proposed extension
   allows a Path Computation Client (PCC) to advertise to a Path
   Computation Element (PCE) that a particular LSP belongs to a
   particular Disjoint Association Group; thus, the PCE knows that the
   LSPs in the same group need to be disjoint from each other.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in 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

Copyright Notice

   Copyright (c) 2020 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
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  Requirements Language
   2.  Terminology
   3.  Motivation
   4.  Applicability
   5.  Protocol Extension
     5.1.  Association Group
     5.2.  Disjoint TLVs
     5.3.  Disjointness Objective Functions
     5.4.  Relationship to SVEC
       5.4.1.  SVEC and OF
     5.5.  P Flag Considerations
     5.6.  Disjointness Computation Issues
   6.  Security Considerations
   7.  IANA Considerations
     7.1.  Association Type
     7.2.  PCEP TLVs
     7.3.  Objective Functions
     7.4.  NO-PATH-VECTOR Bit Flags
     7.5.  PCEP-ERROR Codes
   8.  Manageability Considerations
     8.1.  Control of Function and Policy
     8.2.  Information and Data Models
     8.3.  Liveness Detection and Monitoring
     8.4.  Verification of Correct Operations
     8.5.  Requirements on Other Protocols
     8.6.  Impact on Network Operations
   9.  References
     9.1.  Normative References
     9.2.  Informative References
   Authors' Addresses

1.  Introduction

   [RFC5440] describes the Path Computation Element Communication
   Protocol (PCEP), which enables the communication between a Path
   Computation Client (PCC) and a Path Control Element (PCE) or between
   two PCEs based on the PCE architecture [RFC4655].

   The PCEP Extensions for Stateful PCE Model [RFC8231] describes a set
   of extensions to PCEP to enable active control of MPLS-TE and GMPLS
   tunnels.  [RFC8281] describes the setup and teardown of PCE-initiated
   LSPs under the active stateful PCE model, without the need for local
   configuration on the PCC, thus allowing for a dynamic network.

   [RFC8697] introduces a generic mechanism to create a grouping of LSPs
   in the context of a PCE that can then be used to define associations
   between a set of LSPs and a set of attributes (such as configuration
   parameters or behaviors) and is equally applicable to the active and
   passive modes of a stateful PCE [RFC8231] or a stateless PCE

   This document specifies a PCEP extension to signal that a set of LSPs
   in a particular group should use diverse (disjointed) paths,
   including the requested type of diversity.  Sections 3 and 4 describe
   the property and use of a Disjoint Association Group.  A PCC can use
   this extension to signal to a PCE that a particular LSP belongs to a
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