LSP Modification Using CR-LDP
RFC 3214

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• 03

Network Working Group                                             J. Ash
Request for Comments: 3214                                          AT&T
Category: Standards Track                                         Y. Lee
                                                        Ceterus Networks
                                                        P. Ashwood-Smith
                                                             B. Jamoussi
                                                                D. Fedyk
                                                             D. Skalecki
                                                         Nortel Networks
                                                                   L. Li
                                                            SS8 Networks
                                                            January 2002

                     LSP Modification Using CR-LDP

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document presents an approach to modify the bandwidth and
   possibly other parameters of an established CR-LSP (Constraint-based
   Routed Label Switched Paths) using CR-LDP (Constraint-based Routed
   Label Distribution Protocol) without service interruption.  After a
   CR-LSP is set up, its bandwidth reservation may need to be changed by
   the network operator, due to the new requirements for the traffic
   carried on that CR-LSP.  The LSP modification feature can be
   supported by CR-LDP by use of the _modify_value for the _action
   indicator flag_ in the LSPID TLV.  This feature has application in
   dynamic network resources management where traffic of different
   priorities and service classes is involved.

Ash, et al.                 Standards Track                     [Page 1]
RFC 3214             LSP Modification Using CR-LDP          January 2002

Table of Contents

   1.  Conventions Used in This Document ............................  2
   2.  Introduction .................................................  2
   3.  LSP Modification Using CR-LDP ................................  3
     3.1 Basic Procedure for Resource Modification ..................  3
     3.2 Rerouting LSPs .............................................  5
     3.3 Priority Handling ..........................................  6
     3.4 Modification Failure Case Handling .........................  6
   4.  Application of LSP Bandwidth Modification in Dynamic Resource
       Management ...................................................  7
   5.  Acknowledgments ..............................................  8
   6.  Intellectual Property Considerations .........................  8
   7.  Security Considerations ......................................  8
   8.  References ...................................................  8
   9.  Authors' Addresses ...........................................  9
   10. Full Copyright Statement ..................................... 11

1. Conventions Used in This Document

   L:           LSP (Label Switched Path)
   L-id:        LSPID (LSP Identifier)
   T:           Traffic Parameters
   R:           LSR (Label Switching Router)
   FEC:         Forwarding Equivalence Class
   NHLFE:       Next Hop Label Forwarding Entry
   FTN:         FEC To NHLFE
   TLV:         Type Length Value

   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 RFC 2119 [4].

2. Introduction

   Consider an LSP L1 that has been established with its set of traffic
   parameters T0. A certain amount of bandwidth is reserved along the
   path of L1.  Consider then that some changes are required on L1. For
   example, the bandwidth of L1 needs to be increased to accommodate the
   increased traffic on L1. Or the SLA associated with L1 needs to be
   modified because a different service class is desired.  The network
   operator, in these cases, would like to modify the characteristics of
   L1, for example, to change its traffic parameter set from T0 to T1,
   without releasing the LSP L1 to interrupt the service.  In some other
   cases, network operators may want to reroute a CR-LSP to a different
   path for either improved performance or better network resource
   utilization.  In all these cases, LSP modification is required. In
   section 3 below, a method to modify an active LSP using CR-LDP is

Ash, et al.                 Standards Track                     [Page 2]
RFC 3214             LSP Modification Using CR-LDP          January 2002