Preferred Path Route Graph Structure
draft-ce-lsr-ppr-graph-03

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LSR Working Group                                            U. Chunduri
Internet-Draft                                                 T. Eckert
Intended status: Standards Track                               Futurewei
Expires: September 9, 2020                                 March 8, 2020

                  Preferred Path Route Graph Structure
                       draft-ce-lsr-ppr-graph-03

Abstract

   This document defines a graph structure for the Preferred Path Route
   (PPR) for IS-IS, OSPFv2 and OSPFv3 protocols.  This structure helps
   further scale of the PPR and reduce domain level global entries
   needed in some data planes.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119 [RFC2119],
   RFC8174 [RFC8174] when, and only when they appear in all capitals, as
   shown here.

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Chunduri & Eckert       Expires September 9, 2020               [Page 1]
Internet-Draft    Preferred Path Route Graph Structure        March 2020

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  PPR Graph TLVs  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  IS-IS TLVs  . . . . . . . . . . . . . . . . . . . . . . .   4
       2.1.1.  Branch-ID Sub-TLV . . . . . . . . . . . . . . . . . .   5
       2.1.2.  PPR PDE Sub-TLV . . . . . . . . . . . . . . . . . . .   6
     2.2.  OSPF TLVs . . . . . . . . . . . . . . . . . . . . . . . .   6
       2.2.1.  OSPFv2 TLVs . . . . . . . . . . . . . . . . . . . . .   6
       2.2.2.  OSPFv3 TLVs . . . . . . . . . . . . . . . . . . . . .   6
   3.  Encoding and Processing details . . . . . . . . . . . . . . .   6
     3.1.  S And D bits in PDEs  . . . . . . . . . . . . . . . . . .   7
     3.2.  Graph processing procedure example  . . . . . . . . . . .   8
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     5.1.  IS-IS IANA  . . . . . . . . . . . . . . . . . . . . . . .   9
     5.2.  OSPFv2 IANA . . . . . . . . . . . . . . . . . . . . . . .   9
     5.3.  OSPFv3 IANA . . . . . . . . . . . . . . . . . . . . . . .   9
     5.4.  IGP Parameter IANA  . . . . . . . . . . . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Preferred Path Routing (PPR) is a routing protocol mechanism
   concerned with the creation of a routing path as specified in the
   PPR-Path objects.  These can be signaled via appropriate IGPs (IS-IS,
   OSPFv2, OSPFv3) and indicate the path for a data plane identifier
   (PPR-ID).  With this, all PPR capable nodes along that path establish
   forwarding state for the PPR-ID and any packet destined to the PPR-ID
   would use that path instead of the IGP computed shortest path to the
   destination.

   PPR-Paths and relevant IGP extensions are defined in
   [I-D.chunduri-lsr-isis-preferred-path-routing] and
   [I-D.chunduri-lsr-ospf-preferred-path-routing].  In these IGP