Preferred Path Routing (PPR) in IS-IS
draft-chunduri-lsr-isis-preferred-path-routing-02

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Last updated 2019-02-14
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LSR Working Group                                            U. Chunduri
Internet-Draft                                                     R. Li
Intended status: Standards Track                              Huawei USA
Expires: August 18, 2019                                        R. White
                                                        Juniper Networks
                                                             J. Tantsura
                                                             Apstra Inc.
                                                            L. Contreras
                                                              Telefonica
                                                                   Y. Qu
                                                              Huawei USA
                                                       February 14, 2019

                 Preferred Path Routing (PPR) in IS-IS
           draft-chunduri-lsr-isis-preferred-path-routing-02

Abstract

   This document specifies a Preferred Path Routing (PPR), a routing
   protocol mechanism to simplify the path description of data plane
   traffic in Segment Routing (SR) deployments.  PPR aims to mitigate
   the MTU and data plane processing issues that may result from SR
   packet overheads; and also supports traffic measurement, accounting
   statistics and further attribute extensions along the paths.
   Preferred Path Routing is achieved through the addition of
   descriptions to IS-IS advertised prefixes, and mapping those to a PPR
   data-plane identifier.

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.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

Chunduri, et al.         Expires August 18, 2019                [Page 1]
Internet-Draft    Preferred Path Routing (PPR) in IS-IS    February 2019

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on August 18, 2019.

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Challenges with Increased SID Depth . . . . . . . . . . .   4
     1.3.  Mitigation with MSD . . . . . . . . . . . . . . . . . . .   6
   2.  Preferred Path Routing (PPR)  . . . . . . . . . . . . . . . .   6
     2.1.  PPR-ID and PPR Path Description . . . . . . . . . . . . .   7
   3.  PPR Related TLVs  . . . . . . . . . . . . . . . . . . . . . .   7
     3.1.  PPR-Prefix Sub-TLV  . . . . . . . . . . . . . . . . . . .   9
     3.2.  PPR-ID Sub-TLV  . . . . . . . . . . . . . . . . . . . . .  10
     3.3.  PPR-PDE Sub-TLV . . . . . . . . . . . . . . . . . . . . .  12
     3.4.  PPR-Attributes Sub-TLV  . . . . . . . . . . . . . . . . .  14
   4.  PPR Processing Procedure Example  . . . . . . . . . . . . . .  15
     4.1.  PPR TLV Processing  . . . . . . . . . . . . . . . . . . .  17
     4.2.  Path Fragments  . . . . . . . . . . . . . . . . . . . . .  18
   5.  PPR Data Plane aspects  . . . . . . . . . . . . . . . . . . .  18
     5.1.  SR-MPLS with PPR  . . . . . . . . . . . . . . . . . . . .  18
     5.2.  SRv6 with PPR . . . . . . . . . . . . . . . . . . . . . .  19
     5.3.  PPR Native IP Data Planes . . . . . . . . . . . . . . . .  19
   6.  PPR Scaling Considerations  . . . . . . . . . . . . . . . . .  19
   7.  PPR Traffic Accounting  . . . . . . . . . . . . . . . . . . .  20
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