RFC 3478 (rfc3478) - Page 1 of 12

Graceful Restart Mechanism for Label Distribution Protocol

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Network Working Group                                      M. Leelanivas
Request for Comments: 3478                                    Y. Rekhter
Category: Standards Track                               Juniper Networks
                                                             R. Aggarwal
                                                        Redback Networks
                                                           February 2003


       Graceful Restart Mechanism for Label Distribution Protocol

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 (2003).  All Rights Reserved.

Abstract

   This document describes a mechanism that helps to minimize the
   negative effects on MPLS traffic caused by Label Switching Router's
   (LSR's) control plane restart, specifically by the restart of its
   Label Distribution Protocol (LDP) component, on LSRs that are capable
   of preserving the MPLS forwarding component across the restart.

   The mechanism described in this document is applicable to all LSRs,
   both those with the ability to preserve forwarding state during LDP
   restart and those without (although the latter needs to implement
   only a subset of the mechanism described in this document).
   Supporting (a subset of) the mechanism described here by the LSRs
   that can not preserve their MPLS forwarding state across the restart
   would not reduce the negative impact on MPLS traffic caused by their
   control plane restart, but it would minimize the impact if their
   neighbor(s) are capable of preserving the forwarding state across the
   restart of their control plane and implement the mechanism described
   here.

   The mechanism makes minimalistic assumptions on what has to be
   preserved across restart - the mechanism assumes that only the actual
   MPLS forwarding state has to be preserved; the mechanism does not
   require any of the LDP-related states to be preserved across the
   restart.




Leelanivas, et al.          Standards Track
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