Requirements for Support of Differentiated Services-aware MPLS Traffic Engineering
RFC 3564

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• 07

Network Working Group                                     F. Le Faucheur
Request for Comments: 3564                           Cisco Systems, Inc.
Category: Informational                                           W. Lai
                                                                    AT&T
                                                               July 2003

       Requirements for Support of Differentiated Services-aware
                     MPLS Traffic Engineering

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document presents Service Provider requirements for support of
   Differentiated Services (Diff-Serv)-aware MPLS Traffic Engineering
   (DS-TE).

   Its objective is to provide guidance for the definition, selection
   and specification of a technical solution addressing these
   requirements.  Specification for this solution itself is outside the
   scope of this document.

   A problem statement is first provided.  Then, the document describes
   example applications scenarios identified by Service Providers where
   existing MPLS Traffic Engineering mechanisms fall short and
   Diff-Serv-aware Traffic Engineering can address the needs.  The
   detailed requirements that need to be addressed by the technical
   solution are also reviewed.  Finally, the document identifies the
   evaluation criteria that should be considered for selection and
   definition of the technical solution.

Le Faucheur & Lai            Informational                      [Page 1]
RFC 3564          Requirements for Diff-Serv-aware TE          July 2003

Table of Contents

   Specification Requirements .......................................  2
   1.  Introduction .................................................  3
       1.1.  Problem Statement ......................................  3
       1.2.  Definitions ............................................  3
       1.3.  Mapping of traffic to LSPs .............................  5
   2.  Application Scenarios ........................................  6
       2.1.  Scenario 1: Limiting Proportion of Classes on a Link ...  6
       2.2.  Scenario 2: Maintain relative proportion of traffic ....  6
       2.3.  Scenario 3: Guaranteed Bandwidth Services ..............  8
   3.  Detailed Requirements for DS-TE ..............................  9
       3.1.  DS-TE Compatibility ....................................  9
       3.2.  Class-Types ............................................  9
       3.3.  Bandwidth Constraints .................................. 11
       3.4.  Preemption and TE-Classes .............................. 12
       3.5.  Mapping of Traffic to LSPs ............................. 15
       3.6.  Dynamic Adjustment of Diff-Serv PHBs ................... 15
       3.7.  Overbooking ............................................ 16
       3.8.  Restoration ............................................ 16
   4.  Solution Evaluation Criteria ................................. 16
       4.1.  Satisfying detailed requirements ....................... 17
       4.2.  Flexibility ............................................ 17
       4.3.  Extendibility .......................................... 17
       4.4.  Scalability ............................................ 17
       4.5.  Backward compatibility/Migration ....................... 17
       4.6.  Bandwidth Constraints Model ............................ 18
   5.  Security Considerations ...................................... 18
   6.  Acknowledgment ............................................... 18
   7.  Normative References ......................................... 18
   8.  Informative References ....................................... 19
   9.  Contributing Authors ......................................... 20
   10. Editors' Addresses ........................................... 21
   11. Full Copyright Statement ..................................... 22

Specification Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

Le Faucheur & Lai            Informational                      [Page 2]
RFC 3564          Requirements for Diff-Serv-aware TE          July 2003

1.  Introduction

1.1.  Problem Statement

   Diff-Serv is used by some Service Providers to achieve scalable
   network designs supporting multiple classes of services.

   In some such Diff-Serv networks, where optimization of transmission
   resources on a network-wide basis is not sought, MPLS Traffic
   Engineering (TE) mechanisms may not be used.

   In other networks, where optimization of transmission resources is