Label Sharing for Fast PE Protection
draft-zhang-bess-label-sharing-01

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Last updated 2018-09-19
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INTERNET-DRAFT                                              Mingui Zhang
Intended status: Proposed Standard                             Peng Zhou
                                                         Donald Eastlake
                                                                  Huawei
                                                              Russ White
                                                                    IETF
Expires: March 18, 2018                               September 19, 2018

                  Label Sharing for Fast PE Protection
                 draft-zhang-bess-label-sharing-01.txt

Abstract

   This document describes a method to be used by VPN (Virtual Private
   Network) Service Providers to provide multi-homed CEs with fast
   protection of egress PEs. Egress PEs in a redundant group always
   share the same label in distribution of VPN routes of a VRF. A
   virtual Next Hop (vNH) in the IGP/MPLS backbone is created as the
   common end of LSP tunnels which would otherwise terminate at each
   egress PE. Primary and backup LSP tunnels ended at the vNH are set up
   by MPLS on the basis of existing Interior Gateway Protocol (IGP) Fast
   ReRoute (FRR) mechanisms. If the primary egress PE fails, the backup
   egress PE can recognize the "shared" VPN route label carried by the
   data packets.  Therefore, the failure affected data packets can be
   smoothly rerouted to the backup PE for delivery without changing
   their VPN route label.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

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M. Zhang, et al                                                 [Page 1]
INTERNET-DRAFT                      Label Sharing for Fast PE Protection

Table of Contents

      1. Introduction............................................3
      1.1 Overview...............................................3
      1.3 Terminology............................................4

      2. The Virtual Next Hop....................................5
      3. Link Costs Set Up for IGP FRR...........................6
      4. The LSP Tunnels.........................................8

      5. The VPN Route Label.....................................9
      5.1. Sharing the VPN Route Label...........................9
      5.1.1 Option A: Reserved Label Ranges per RG...............9
      5.1.2 Option B: The Label Swapping Table..................10
      5.2 Binding to LSP Tunnels................................10

      6. Examples To Walk Through...............................11
      6.1 Label Distribution Procedure..........................11
      6.2 Protection Procedure..................................11

      7. Operations.............................................12
      7.1 Label Space Management for Option A...................12
      7.2 Backup LSP Tunnel Exceptions..........................12

      8. Security Considerations................................13
      9. IANA Considerations....................................13

      Acknowledgements..........................................13
      Normative References......................................13
      Informative References....................................14

      Appendix A: Generating OSPF LSAs..........................15
      Appendix B: Generating IS-IS LSPs.........................17

      Authors' Addresses........................................20

M. Zhang, et al                                                 [Page 2]
INTERNET-DRAFT                      Label Sharing for Fast PE Protection

1. Introduction

   For the sake of reliability, ISPs often connect one CE (Customer
   Edge) device to multiple PE (Provider Edge) devices. When the primary
   egress PE fails, a backup egress PE continues to offer VPN
   connectivity to the CE. If local repair is performed by the upstream
   neighbor of the primary egress PE on the data path, it's possible to
   achieve a 50 msec switchover.

   VPN (Virtual Private Network) routes learnt from CEs are distributed
   by egress PEs to ingress PEs that need to know these VPN routes.
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