Node Behavior upon Originating and Receiving Resource Reservation Protocol (RSVP) Path Error Messages
RFC 5711

Internet Engineering Task Force (IETF)                  JP. Vasseur, Ed.
Request for Comments: 5711                                    G. Swallow
Updates: 3209                                        Cisco Systems, Inc.
Category: Standards Track                                       I. Minei
ISSN: 2070-1721                                         Juniper Networks
                                                            January 2010

   Node Behavior upon Originating and Receiving Resource Reservation
                  Protocol (RSVP) Path Error Messages

Abstract

   The aim of this document is to describe a common practice with regard
   to the behavior of nodes that send and receive a Resource Reservation
   Protocol (RSVP) Traffic Engineering (TE) Path Error messages for a
   preempted Multiprotocol Label Switching (MPLS) or Generalized MPLS
   (GMPLS) Traffic Engineering Label Switched Path (TE LSP).  (For
   reference to the notion of TE LSP preemption, see RFC 3209.)  This
   document does not define any new protocol extensions.

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/rfc5711.

Vasseur, et al.              Standards Track                    [Page 1]
RFC 5711             Node Behavior with RSVP PathErr        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. Requirements Language ......................................3
   2. Protocol Behavior ...............................................3
      2.1. Behavior at Detecting Nodes ................................4
      2.2. Behavior at Receiving Nodes ................................5
      2.3. Data-Plane Behavior ........................................5
   3. RSVP PathErr Messages for a Preempted TE LSP ....................5
   4. Security Considerations .........................................5
   5. Acknowledgements ................................................6
   6. References ......................................................6
      6.1. Normative References .......................................6
      6.2. Informative References .....................................6

Vasseur, et al.              Standards Track                    [Page 2]
RFC 5711             Node Behavior with RSVP PathErr        January 2010

1.  Introduction

   The aim of this document is to describe a common practice with regard
   to the behavior of a node sending a Resource Reservation Protocol
   (RSVP) Traffic Engineering (TE) Path Error message and to the
   behavior of a node receiving an RSVP Path Error message for a
   preempted Multiprotocol Label Switching (MPLS) and Generalized MPLS
   (GMPLS) Traffic Engineering Label Switched Path (TE LSP).  (For
   reference to the notion of TE LSP preemption, see [RFC3209]).

   [RFC2205] defines two RSVP error message types: PathErr and ResvErr
   that are generated when an error occurs.  Path Error messages
   (PathErr) are used to report errors and travel upstream toward the
   head-end of the flow.  Resv Error messages (ResvErr) travel
   downstream toward the tail-end of the flow.

   This document describes only PathErr message processing for the
   specific case of a preempted TE LSP, where the term preemption is
   defined in [RFC3209].

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this