Loop avoidance using Segment Routing
draft-bashandy-rtgwg-segment-routing-uloop-06

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Network Working Group                                    Ahmed Bashandy
Internet Draft                                               Individual
Intended status: Standards Track                      Clarence Filsfils
Expires: January 2020                               Cisco Systems, Inc.
                                                     Stephane Litkowski
                                                         Bruno Decraene
                                                                 Orange
                                                        Pierre Francois
                                                              INSA Lyon
                                                           Peter Psenak
                                                          Cisco Systems
                                                           July 6, 2019

                  Loop avoidance using Segment Routing
              draft-bashandy-rtgwg-segment-routing-uloop-06

Abstract

This document presents a mechanism aimed at providing loop avoidance
in the case of IGP network convergence event.  The solution relies on
the temporary use of SR policies ensuring loop-freeness over the
post-convergence paths from the converging node to the destination.

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Bashandy               Expires January 6, 2020                 [Page 1]
Internet-Draft            SR Loop Avoidance                   July 2019

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Table of Contents

   1. Introduction...................................................2
      1.1. Conventions used in this document.........................4
   2. Loop-free two-stage convergence process........................4
   3. Computing loop-avoiding SR policies............................5
   4. Analysis.......................................................5
      4.1. Incremental Deployment....................................5
      4.2. No impact on capacity planning............................5
   5. Security Considerations........................................6
   6. IANA Considerations............................................6
   7. Contributors...................................................6
   8. References.....................................................6
      8.1. Normative References......................................6
      8.2. Informative References....................................6
   9. Acknowledgments................................................6

1. Introduction

   Forwarding loops happen during the convergence of the IGP, as a
   result of transient inconsistency among forwarding states of the
   nodes of the network.

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Internet-Draft            SR Loop Avoidance                   July 2019