The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS and GMPLS
RFC 6805
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RFC - Informational
(November 2012; No errata)
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2015-10-14
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draft-king-pce-hierarchy-fwk
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IETF
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RFC 6805 (Informational)
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Responsible AD |
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Stewart Bryant
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Julien Meuric (julien.meuric@orange.com) is the document shepherd.
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Internet Engineering Task Force (IETF) D. King, Ed.
Request for Comments: 6805 A. Farrel, Ed.
Category: Informational Old Dog Consulting
ISSN: 2070-1721 November 2012
The Application of the Path Computation Element Architecture to the
Determination of a Sequence of Domains in MPLS and GMPLS
Abstract
Computing optimum routes for Label Switched Paths (LSPs) across
multiple domains in MPLS Traffic Engineering (MPLS-TE) and GMPLS
networks presents a problem because no single point of path
computation is aware of all of the links and resources in each
domain. A solution may be achieved using the Path Computation
Element (PCE) architecture.
Where the sequence of domains is known a priori, various techniques
can be employed to derive an optimum path. If the domains are simply
connected, or if the preferred points of interconnection are also
known, the Per-Domain Path Computation technique can be used. Where
there are multiple connections between domains and there is no
preference for the choice of points of interconnection, the Backward-
Recursive PCE-based Computation (BRPC) procedure can be used to
derive an optimal path.
This document examines techniques to establish the optimum path when
the sequence of domains is not known in advance. The document shows
how the PCE architecture can be extended to allow the optimum
sequence of domains to be selected, and the optimum end-to-end path
to be derived through the use of a hierarchical relationship between
domains.
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 5741.
King & Farrel Informational [Page 1]
RFC 6805 PCE Hierarchy Framework November 2012
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6805.
Copyright Notice
Copyright (c) 2012 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
(http://trustee.ietf.org/license-info) 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 ....................................................4
1.1. Problem Statement ..........................................5
1.2. Definition of a Domain .....................................5
1.3. Assumptions and Requirements ...............................6
1.3.1. Metric Objectives ...................................6
1.3.2. Diversity ...........................................7
1.3.2.1. Physical Diversity .........................7
1.3.2.2. Domain Diversity ...........................7
1.3.3. Existing Traffic Engineering Constraints ............7
1.3.4. Commercial Constraints ..............................8
1.3.5. Domain Confidentiality ..............................8
1.3.6. Limiting Information Aggregation ....................8
1.3.7. Domain Interconnection Discovery ....................8
1.4. Terminology ................................................8
2. Examination of Existing PCE Mechanisms ..........................9
2.1. Per-Domain Path Computation ................................9
2.2. Backward-Recursive PCE-Based Computation ..................10
2.2.1. Applicability of BRPC When the Domain Path
is Not Known .......................................11
3. Hierarchical PCE ...............................................12
4. Hierarchical PCE Procedures ....................................13
4.1. Objective Functions and Policy ............................13
4.2. Maintaining Domain Confidentiality ........................14
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