PathErr Message Triggered MPLS and GMPLS LSP Reroutes
RFC 5710

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Internet Engineering Task Force (IETF)                         L. Berger
Request for Comments: 5710                                          LabN
Category: Standards Track                               D. Papadimitriou
ISSN: 2070-1721                                           Alcatel Lucent
                                                             JP. Vasseur
                                                                   Cisco
                                                            January 2010

         PathErr Message Triggered MPLS and GMPLS LSP Reroutes

Abstract

   This document describes how Resource ReserVation Protocol (RSVP)
   PathErr messages may be used to trigger rerouting of Multi-Protocol
   Label Switching (MPLS) and Generalized MPLS (GMPLS) point-to-point
   Traffic Engineering (TE) Label Switched Paths (LSPs) without first
   removing LSP state or resources.  Such LSP rerouting may be desirable
   in a number of cases, including, for example, soft-preemption and
   graceful shutdown.  This document describes the usage of existing
   Standards Track mechanisms to support LSP rerouting.  In this case,
   it relies on mechanisms already defined as part of RSVP-TE and simply
   describes a sequence of actions to be executed.  While existing
   protocol definitions can be used to support reroute applications,
   this document also defines a new reroute-specific error code to allow
   for the future definition of reroute-application-specific error
   values.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   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/rfc5710.

Berger, et al.              Standards Track                     [Page 1]
RFC 5710              MPLS and GMPLS LSP Reroutes           January 2010

Copyright Notice

   Copyright (c) 2010 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 ....................................................3
      1.1. Conventions Used in This Document ..........................4
   2. Reroute Requests ................................................4
      2.1. Processing at Requesting Node ..............................4
           2.1.1. Reroute Request Timeouts ............................5
      2.2. Processing at Upstream Node ................................6
      2.3. Processing at Ingress ......................................6
   3. Example Reroute Requests ........................................7
      3.1. Node Reroute Request .......................................7
      3.2. Interface Reroute Request ..................................7
      3.3. Component Reroute Request ..................................8
      3.4. Label Reroute Request ......................................9
   4. IANA Considerations .............................................9
   5. Security Considerations ........................................10
   6. References .....................................................10
      6.1. Normative References ......................................10
      6.2. Informative References ....................................11
   7. Acknowledgments ................................................11

Berger, et al.              Standards Track                     [Page 2]
RFC 5710              MPLS and GMPLS LSP Reroutes           January 2010

1.  Introduction

   The Resource ReserVation Protocol (RSVP), see [RFC2205], has been
   extended to support the control of Traffic Engineering (TE) Label
   Switched Paths (LSPs) for both Multi-Protocol Label Switching (MPLS)
   and Generalized MPLS (GMPLS) in, respectively, [RFC3209] and
   [RFC3473].  In all cases, a PathErr message is used to report errors
   to nodes upstream of the error-detecting node.  As defined in
   [RFC2205] and left unmodified by [RFC3209], PathErr messages "do not
   change path state in the nodes through which they pass".