Routing-Related Design Choices for IPv6 Networks
draft-ietf-v6ops-design-choices-12

Document Type Active Internet-Draft (v6ops WG)
Last updated 2016-11-13
Replaces draft-matthews-v6ops-design-guidelines
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V6OPS Working Group                                          P. Matthews
Internet-Draft                                                     Nokia
Intended status: Informational                              V. Kuarsingh
Expires: May 17, 2017                                              Cisco
                                                       November 13, 2016

            Routing-Related Design Choices for IPv6 Networks
                   draft-ietf-v6ops-design-choices-12

Abstract

   This document presents advice on certain routing-related design
   choices that arise when designing IPv6 networks (both dual-stack and
   IPv6-only).  The intended audience is someone designing an IPv6
   network who is knowledgeable about best current practices around IPv4
   network design, and wishes to learn the corresponding practices for
   IPv6.

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
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   This Internet-Draft will expire on May 17, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of

Matthews & Kuarsingh      Expires May 17, 2017                  [Page 1]
Internet-Draft             IPv6 Design Choices             November 2016

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Design Choices  . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Addresses . . . . . . . . . . . . . . . . . . . . . . . .   3
       2.1.1.  Where to Use Addresses  . . . . . . . . . . . . . . .   4
       2.1.2.  Which Addresses to Use  . . . . . . . . . . . . . . .   6
     2.2.  Interfaces  . . . . . . . . . . . . . . . . . . . . . . .   7
       2.2.1.  Mix IPv4 and IPv6 on the Same Layer-3 Interface?  . .   7
     2.3.  Static Routes . . . . . . . . . . . . . . . . . . . . . .   8
       2.3.1.  Link-Local Next-Hop in a Static Route?  . . . . . . .   8
     2.4.  IGPs  . . . . . . . . . . . . . . . . . . . . . . . . . .   9
       2.4.1.  IGP Choice  . . . . . . . . . . . . . . . . . . . . .   9
       2.4.2.  IS-IS Topology Mode . . . . . . . . . . . . . . . . .  12
       2.4.3.  RIP / RIPng . . . . . . . . . . . . . . . . . . . . .  13
     2.5.  BGP . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
       2.5.1.  Which Transport for Which Routes? . . . . . . . . . .  14
         2.5.1.1.  BGP Sessions for Unlabeled Routes . . . . . . . .  16
         2.5.1.2.  BGP sessions for Labeled or VPN Routes  . . . . .  17
       2.5.2.  eBGP Endpoints: Global or Link-Local Addresses? . . .  18
   3.  General Observations  . . . . . . . . . . . . . . . . . . . .  19
     3.1.  Use of Link-Local Addresses . . . . . . . . . . . . . . .  19
     3.2.  Separation of IPv4 and IPv6 . . . . . . . . . . . . . . .  20
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  20
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  21
   7.  Informative References  . . . . . . . . . . . . . . . . . . .  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  25

1.  Introduction

   This document discusses routing-related design choices that arise
   when designing an IPv6-only or dual-stack network.  The focus is on
   choices that do not come up when designing an IPv4-only network.  The
   document presents each choice and the alternatives, and then
   discusses the pros and cons of the alternatives in detail.  Where
   consensus currently exists around the best practice, this is
   documented; otherwise the document simply summarizes the current
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