Applicability of the Path Computation Element to Inter-area and Inter-AS MPLS and GMPLS Traffic Engineering
RFC 8694

Document Type RFC - Informational (December 2019; No errata)
Authors Daniel King  , Haomian Zheng 
Last updated 2019-12-18
Replaces draft-king-pce-inter-area-as-applicability
Stream Internent Engineering Task Force (IETF)
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IESG IESG state RFC 8694 (Informational)
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Internet Engineering Task Force (IETF)                           D. King
Request for Comments: 8694                            Old Dog Consulting
Category: Informational                                郑好棉 (H. Zheng)
ISSN: 2070-1721                   华为技术有限公司 (Huawei Technologies)
                                                           December 2019

Applicability of the Path Computation Element to Inter-area and Inter-AS
                   MPLS and GMPLS Traffic Engineering


   The Path Computation Element (PCE) may be used for computing services
   that traverse multi-area and multi-Autonomous System (multi-AS)
   Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS)
   Traffic-Engineered (TE) networks.

   This document examines the applicability of the PCE architecture,
   protocols, and protocol extensions for computing multi-area and
   multi-AS paths in MPLS and GMPLS networks.

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 candidates 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

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.  Domains
     1.2.  Path Computation
       1.2.1.  PCE-Based Path Computation Procedure
     1.3.  Traffic Engineering Aggregation and Abstraction
     1.4.  Traffic-Engineered Label Switched Paths
     1.5.  Inter-area and Inter-AS-capable PCE Discovery
     1.6.  Objective Functions
   2.  Terminology
   3.  Issues and Considerations
     3.1.  Multihoming
     3.2.  Destination Location
     3.3.  Domain Confidentiality
   4.  Domain Topologies
     4.1.  Selecting Domain Paths
     4.2.  Domain Sizes
     4.3.  Domain Diversity
     4.4.  Synchronized Path Computations
     4.5.  Domain Inclusion or Exclusion
   5.  Applicability of the PCE to Inter-area Traffic Engineering
     5.1.  Inter-area Routing
       5.1.1.  Area Inclusion and Exclusion
       5.1.2.  Strict Explicit Path and Loose Path
       5.1.3.  Inter-Area Diverse Path Computation
   6.  Applicability of the PCE to Inter-AS Traffic Engineering
     6.1.  Inter-AS Routing
       6.1.1.  AS Inclusion and Exclusion
     6.2.  Inter-AS Bandwidth Guarantees
     6.3.  Inter-AS Recovery
     6.4.  Inter-AS PCE Peering Policies
   7.  Multi-domain PCE Deployment Options
     7.1.  Traffic Engineering Database and Synchronization
       7.1.1.  Applicability of BGP-LS to PCE
     7.2.  Pre-planning and Management-Based Solutions
   8.  Domain Confidentiality
     8.1.  Loose Hops
     8.2.  Confidential Path Segments and Path-Keys
   9.  Point to Multipoint
   10. Optical Domains
     10.1.  Abstraction and Control of TE Networks (ACTN)
   11. Policy
   12. Manageability Considerations
     12.1.  Control of Function and Policy
     12.2.  Information and Data Models
     12.3.  Liveness Detection and Monitoring
     12.4.  Verifying Correct Operation
     12.5.  Impact on Network Operation
   13. Security Considerations
     13.1.  Multi-domain Security
   14. IANA Considerations
   15. References
     15.1.  Normative References
     15.2.  Informative References
   Authors' Addresses

1.  Introduction

   Computing paths across large multi-domain environments may require
   special computational components and cooperation between entities in
   different domains capable of complex path computation.

   Issues that may exist when routing in multi-domain networks include
   the following:

   *  There is often a lack of full topology and TE information across

   *  No single node has the full visibility to determine an optimal or
      even feasible end-to-end path across domains.

   *  Knowing how to evaluate and select the exit point and next domain
      boundary from a domain.
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