Path Computation Element Communication Protocol (PCEP) Extensions for the Hierarchical Path Computation Element (H-PCE) Architecture
RFC 8685

Document Type RFC - Proposed Standard (December 2019; No errata)
Authors Fatai Zhang  , Quintin Zhao  , Oscar de Dios  , R. Casellas , Daniel King 
Last updated 2019-12-13
Replaces draft-zhang-pce-hierarchy-extensions, draft-dwpz-pce-domain-diverse
Stream IETF
Formats plain text html xml pdf htmlized bibtex
Stream WG state Submitted to IESG for Publication
Document shepherd Dhruv Dhody
Shepherd write-up Show (last changed 2019-02-12)
IESG IESG state RFC 8685 (Proposed Standard)
Action Holders
Consensus Boilerplate Yes
Telechat date
Responsible AD Deborah Brungard
Send notices to Dhruv Dhody <>
IANA IANA review state IANA OK - Actions Needed
IANA action state RFC-Ed-Ack

Internet Engineering Task Force (IETF)                          F. Zhang
Request for Comments: 8685                                       Q. Zhao
Category: Standards Track                                         Huawei
ISSN: 2070-1721                                      O. Gonzalez de Dios
                                                          Telefonica I+D
                                                             R. Casellas
                                                                 D. King
                                                      Old Dog Consulting
                                                           December 2019

   Path Computation Element Communication Protocol (PCEP) Extensions
   for the Hierarchical Path Computation Element (H-PCE) Architecture


   The Hierarchical Path Computation Element (H-PCE) architecture is
   defined in RFC 6805.  It provides a mechanism to derive an optimum
   end-to-end path in a multi-domain environment by using a hierarchical
   relationship between domains to select the optimum sequence of
   domains and optimum paths across those domains.

   This document defines extensions to the Path Computation Element
   Communication Protocol (PCEP) to support H-PCE procedures.

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) 2019 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
   to this document.  Code Components extracted from this document must
   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.  Scope
     1.2.  Terminology
     1.3.  Requirements Language
   2.  Requirements for the H-PCE Architecture
     2.1.  Path Computation Requests
       2.1.1.  Qualification of PCEP Requests
       2.1.2.  Multi-domain Objective Functions
       2.1.3.  Multi-domain Metrics
     2.2.  Parent PCE Capability Advertisement
     2.3.  PCE Domain Identification
     2.4.  Domain Diversity
   3.  PCEP Extensions
     3.1.  Applicability to PCC-PCE Communications
     3.2.  OPEN Object
       3.2.1.  H-PCE-CAPABILITY TLV  Backwards Compatibility
       3.2.2.  Domain-ID TLV
     3.3.  RP Object
       3.3.1.  H-PCE-FLAG TLV
       3.3.2.  Domain-ID TLV
     3.4.  Objective Functions
       3.4.1.  OF Codes
       3.4.2.  OF Object
     3.5.  METRIC Object
     3.6.  SVEC Object
     3.7.  PCEP-ERROR Object
       3.7.1.  Hierarchical PCE Error-Type
     3.8.  NO-PATH Object
   4.  H-PCE Procedures
     4.1.  OPEN Procedure between Child PCE and Parent PCE
     4.2.  Procedure for Obtaining the Domain Sequence
   5.  Error Handling
   6.  Manageability Considerations
     6.1.  Control of Function and Policy
       6.1.1.  Child PCE
       6.1.2.  Parent PCE
       6.1.3.  Policy Control
     6.2.  Information and Data Models
     6.3.  Liveness Detection and Monitoring
     6.4.  Verifying Correct Operations
     6.5.  Requirements on Other Protocols
     6.6.  Impact on Network Operations
   7.  IANA Considerations
     7.1.  PCEP TLV Type Indicators
     7.2.  H-PCE-CAPABILITY TLV Flags
     7.3.  Domain-ID TLV Domain Type
     7.4.  H-PCE-FLAG TLV Flags
     7.5.  OF Codes
     7.6.  METRIC Object Types
     7.7.  New PCEP Error-Types and Values
     7.8.  New NO-PATH-VECTOR TLV Bit Flag
     7.9.  SVEC Flag
   8.  Security Considerations
   9.  References
     9.1.  Normative References
     9.2.  Informative References
   Authors' Addresses

1.  Introduction

   The Path Computation Element Communication Protocol (PCEP) provides a
   mechanism for Path Computation Elements (PCEs) and Path Computation
   Clients (PCCs) to exchange requests for path computation and
   responses that provide computed paths.

   The capability to compute the routes of end-to-end inter-domain MPLS
   Traffic Engineering (MPLS-TE) and GMPLS Label Switched Paths (LSPs)
Show full document text