Maximum Allocation Bandwidth Constraints Model for Diffserv-aware MPLS Traffic Engineering
RFC 4125

 
Document Type RFC - Experimental (June 2005; No errata)
Last updated 2013-03-02
Stream IETF
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Stream WG state (None)
Consensus Unknown
Document shepherd No shepherd assigned
IESG IESG state RFC 4125 (Experimental)
Telechat date
Responsible AD Bert Wijnen
Send notices to <ejk@tech.org>, <jboyle@pdnets.com>
Network Working Group                                     F. Le Faucheur
Request for Comments: 4125                           Cisco Systems, Inc.
Category: Experimental                                            W. Lai
                                                               AT&T Labs
                                                               June 2005

         Maximum Allocation Bandwidth Constraints Model for
                Diffserv-aware MPLS Traffic Engineering

Status of This Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document provides specifications for one Bandwidth Constraints
   Model for Diffserv-aware MPLS Traffic Engineering, which is referred
   to as the Maximum Allocation Model.

Table of Contents

   1. Introduction ....................................................2
      1.1. Specification of Requirements ..............................2
   2. Definitions .....................................................2
   3. Maximum Allocation Model Definition .............................3
   4. Example Formulas for Computing "Unreserved TE-Class [i]" with
      Maximum Allocation Model.........................................6
   5. Security Considerations .........................................7
   6. IANA Considerations .............................................7
   7. Acknowledgements ................................................7
   Appendix A: Addressing [DSTE-REQ] Scenarios.........................8
   Normative References...............................................10
   Informative References.............................................10

Le Faucheur & Lai             Experimental                      [Page 1]
RFC 4125           Maximum Allocation Model for DS-TE          June 2005

1.  Introduction

   [DSTE-REQ] presents the Service Providers requirements for support of
   Diffserv-aware MPLS Traffic Engineering (DS-TE).  This includes the
   fundamental requirement to be able to enforce different Bandwidth
   Constraints for different classes of traffic.

   [DSTE-REQ] also defines the concept of Bandwidth Constraints Model
   for DS-TE and states that "The DS-TE technical solution MUST specify
   at least one Bandwidth Constraints Model and MAY specify multiple
   Bandwidth Constraints Models."

   This document provides a detailed description of one particular
   Bandwidth Constraints Model for DS-TE, which is introduced in
   [DSTE-REQ] and called the Maximum Allocation Model (MAM).

   [DSTE-PROTO] specifies the IGP and RSVP-TE signaling extensions for
   support of DS-TE.  These extensions support MAM.

1.1.  Specification of 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].

2.  Definitions

   For readability, a number of definitions from [DSTE-REQ] are repeated
   here:

   Class-Type (CT): the set of Traffic Trunks crossing a link that is
                    governed by a specific set of Bandwidth Constraints.
                    CT is used for the purposes of link bandwidth
                    allocation, constraint-based routing, and admission
                    control.  A given Traffic Trunk belongs to the same
                    CT on all links.

   TE-Class:        A pair of:

                    i. a Class-Type

                    ii. a preemption priority allowed for that Class-
                    Type.  This means that an LSP transporting a Traffic
                    Trunk from that Class-Type can use that preemption
                    priority as the set-up priority, as the holding
                    priority or both.

Le Faucheur & Lai             Experimental                      [Page 2]
RFC 4125           Maximum Allocation Model for DS-TE          June 2005

   A number of recovery mechanisms, under investigation or specification
   in the IETF, take advantage of the concept of bandwidth sharing
   across particular sets of LSPs.  "Shared Mesh Restoration" in
   [GMPLS-RECOV] and "Facility-based Computation Model" in [MPLS-BACKUP]
   are example mechanisms that increase bandwidth efficiency by sharing
   bandwidth across backup LSPs protecting against independent failures.
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