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Prioritized Treatment of Specific OSPF Version 2 Packets and Congestion Avoidance (RFC4222)

IP.com Disclosure Number: IPCOM000130119D
Original Publication Date: 2005-Oct-01
Included in the Prior Art Database: 2005-Oct-12
Document File: 16 page(s) / 34K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Choudhury: AUTHOR [+2]

Abstract

This document recommends methods that are intended to improve the scalability and stability of large networks using Open Shortest Path First (OSPF) Version 2 protocol. The methods include processing OSPF Hellos and Link State Advertisement (LSA) Acknowledgments at a higher priority compared to other OSPF packets, and other congestion avoidance procedures.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 8% of the total text.

Network Working Group                                  G. Choudhury, Ed.
Request for Comments: 4222                                          AT&T
BCP: 112                                                    October 2005
Category: Best Current Practice


            Prioritized Treatment of Specific OSPF Version 2
                    Packets and Congestion Avoidance

Status of This Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document recommends methods that are intended to improve the
   scalability and stability of large networks using Open Shortest Path
   First (OSPF) Version 2 protocol.  The methods include processing OSPF
   Hellos and Link State Advertisement (LSA) Acknowledgments at a higher
   priority compared to other OSPF packets, and other congestion
   avoidance procedures.

Table of Contents

   1. Introduction...................................................2
   2. Recommendations................................................3
   3. Security Considerations........................................6
   4. Acknowledgments................................................6
   5. Normative References...........................................6
   6. Informative References.........................................7
   Appendix A. LSA Storm: Causes and Impact..........................8
   Appendix B. List of Variables and Values.........................10
   Appendix C. Other Recommendations and Suggestions................11


Choudhury, Ed.           Best Current Practice                  [Page 1]
RFC 4222                 Prioritized Treatment              October 2005


1.  Introduction

   In this document, OSPF refers to OSPFv2 [Ref1].  The scalability and
   stability improvement techniques described here may also apply to
   OSPFv3 [Ref2], but that will require further study and operational
   experience.

   A large network running OSPF protocol may occasionally experience the
   simultaneous or near-simultaneous update of a large number of link
   state advertisements, or LSAs.  This is particularly true if OSPF
   traffic engineering extension [Ref3] is used that may significantly
   increase the number of LSAs in the network.  We call this event an
   LSA storm and it may be initiated by an unscheduled failure or a
   scheduled maintenance event.  The failure may be hardware, software,
   or procedural in nature.

   The LSA storm causes high CPU and memory utilization at the router
   causing incoming packets to be delayed or d...