Description of the Resource Reservation Protocol - Traffic-Engineered (RSVP-TE) Graceful Restart Procedures
RFC 5495

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Network Working Group                                              D. Li
Request for Comments: 5495                                        J. Gao
Category: Informational                                           Huawei
                                                        A. Satyanarayana
                                                                   Cisco
                                                             S. Bardalai
                                                                 Fujitsu
                                                              March 2009

                          Description of the
     Resource Reservation Protocol - Traffic-Engineered (RSVP-TE)
                      Graceful Restart Procedures

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.

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Li, et al.                   Informational                      [Page 1]
RFC 5495          RSVP-TE Graceful Restart Procedures      February 2009

Abstract

   The Hello message for the Resource Reservation Protocol (RSVP) has
   been defined to establish and maintain basic signaling node
   adjacencies for Label Switching Routers (LSRs) participating in a
   Multiprotocol Label Switching (MPLS) traffic-engineered (TE) network.
   The Hello message has been extended for use in Generalized MPLS
   (GMPLS) networks for state recovery of control channel or nodal
   faults.

   The GMPLS protocol definitions for RSVP also allow a restarting node
   to learn which label it previously allocated for use on a Label
   Switched Path (LSP).

   Further RSVP protocol extensions have been defined to enable a
   restarting node to recover full control plane state by exchanging
   RSVP messages with its upstream and downstream neighbors.

   This document provides an informational clarification of the control
   plane procedures for a GMPLS network when there are multiple node
   failures, and describes how full control plane state can be recovered
   in different scenarios where the order in which the nodes restart is
   different.

   This document does not define any new processes or procedures.  All
   protocol mechanisms are already defined in the referenced documents.

Li, et al.                   Informational                      [Page 2]
RFC 5495          RSVP-TE Graceful Restart Procedures      February 2009

Table of Contents

   1. Introduction ....................................................3
   2. Existing Procedures for Single Node Restart .....................4
      2.1. Procedures Defined in RFC 3473 .............................4
      2.2. Procedures Defined in RFC 5063 .............................5
   3. Multiple Node Restart Scenarios .................................6
   4. RSVP State ......................................................7
   5. Procedures for Multiple Node Restart ............................7
      5.1. Procedures for the Normal Node .............................8
      5.2. Procedures for the Restarting Node .........................8
           5.2.1. Procedures for Scenario 1 ...........................8
           5.2.2. Procedures for Scenario 2 ...........................9
           5.2.3. Procedures for Scenario 3 ..........................11
           5.2.4. Procedures for Scenario 4 ..........................12
           5.2.5. Procedures for Scenario 5 ..........................12
      5.3. Consideration of the Reuse of Data Plane Resources ........12
      5.4. Consideration of Management Plane Intervention ............13
   6. Clarification of Restarting Node Procedure .....................13
   7. Security Considerations ........................................15