Loop avoidance using Segment Routing
draft-francois-rtgwg-segment-routing-uloop-01

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Network Working Group                                   Pierre Francois
Internet Draft                                   Individual Contributor
Intended status: Informational                        Clarence Filsfils
Expires: June 2017                                       Ahmed Bashandy
                                                    Cisco Systems, Inc.
                                                     Stephane Litkowski
                                                                 Orange
                                                      December 14, 2016

                  Loop avoidance using Segment Routing
              draft-francois-rtgwg-segment-routing-uloop-01

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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Internet-Draft                SR TI-LFA                   December 2016

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Table of Contents

   1. Introduction...................................................2
      1.1. Conventions used in this document.........................3
   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.

   This document provides a mechanism leveraging Segment Routing to
   ensure loop-freeness during the IGP reconvergence process following
   a link-state change event.

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