BGP Prefix Independent Convergence
draft-ietf-rtgwg-bgp-pic-10

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Network Working Group                                  A. Bashandy, Ed.
Internet Draft                                                   Arrcus
Intended status: Informational                              C. Filsfils
Expires: April 2020                                       Cisco Systems
                                                           P. Mohapatra
                                                       Sproute Networks
                                                        October 2, 2019

                    BGP Prefix Independent Convergence
                      draft-ietf-rtgwg-bgp-pic-10.txt

Abstract

In the network comprising thousands of iBGP peers exchanging millions
of routes, many routes are reachable via more than one next-hop.
Given the large scaling targets, it is desirable to restore traffic
after failure in a time period that does not depend on the number of
BGP prefixes. In this document we proposed an architecture by which
traffic can be re-routed to ECMP or pre-calculated backup paths in a
timeframe that does not depend on the number of BGP prefixes. The
objective is achieved through organizing the forwarding data
structures in a hierarchical manner and sharing forwarding elements
among the maximum possible number of routes. The proposed technique
achieves prefix independent convergence while ensuring incremental
deployment, complete automation, and zero management and provisioning
effort. It is noteworthy to mention that the benefits of BGP-PIC are
hinged on the existence of more than one path whether as ECMP or
primary-backup.

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Bashandy                Expires April 2, 2020                  [Page 1]
Internet-Draft    BGP Prefix Independent Convergence       October 2019

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Table of Contents

   1. Introduction...................................................3
      1.1. Terminology...............................................4
   2. Overview.......................................................5
      2.1. Dependency................................................6
         2.1.1. Hierarchical Hardware FIB............................6
         2.1.2. Availability of more than one primary or secondary BGP
         next-hops...................................................7
      2.2. BGP-PIC Illustration......................................7
   3. Constructing the Shared Hierarchical Forwarding Chain..........9
      3.1. Constructing the BGP-PIC forwarding Chain.................9
      3.2. Example: Primary-Backup Path Scenario....................10
   4. Forwarding Behavior...........................................11

Bashandy                Expires April 2, 2020                  [Page 2]
Internet-Draft    BGP Prefix Independent Convergence       October 2019