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Versions: (draft-palet-ietf-v6ops-ipv6-only) 00 01 02 03 04

v6ops                                                  J. Palet Martinez
Internet-Draft                                          The IPv6 Company
Intended status: Informational                              July 3, 2019
Expires: January 4, 2020


                    IPv6-only Terminology Definition
                     draft-palet-v6ops-ipv6-only-04

Abstract

   This document defines the terminology regarding the usage of
   expressions such as "IPv6-only", in order to avoid confusions when
   using them in IETF and other documents.  The goal is that the
   reference to "IPv6-only" describes the actual native functionality
   being used, not the actual protocol support.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
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   This Internet-Draft will expire on January 4, 2020.

Copyright Notice

   Copyright (c) 2019 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
   (https://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
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Context . . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Definition of IPv6-only . . . . . . . . . . . . . . . . . . .   3
   4.  Dual-stack  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Native dual-stack . . . . . . . . . . . . . . . . . . . . . .   3
   6.  IPv6-only network . . . . . . . . . . . . . . . . . . . . . .   4
   7.  IPv6-only WAN/access  . . . . . . . . . . . . . . . . . . . .   4
   8.  IPv6-only LAN . . . . . . . . . . . . . . . . . . . . . . . .   4
   9.  IPv6-only host/router . . . . . . . . . . . . . . . . . . . .   4
   10. Transitional IPv6 host/router . . . . . . . . . . . . . . . .   4
   11. Other cases . . . . . . . . . . . . . . . . . . . . . . . . .   4
   12. Security Considerations . . . . . . . . . . . . . . . . . . .   5
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   14. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Due to the nature of the Internet and the different types of users,
   parts of a network, providers, flows, etc., there is not a single and
   easy way to categorically say something such as "IPv6-only".

   The goal of this document is to depict this situation and agree in a
   common language to be used for IETF and other documents, in order to
   facilitate ourselves and future readers, the correct understanding of
   what we are talking about.

   Note that all the references in this document are regarding the
   actual usage of IPv4/IPv6, not the support of those protocols by
   nodes.  For example, a device or access network may support both IPv4
   and IPv6, however actually is only "natively" forwarding IPv6,
   because the link used for that communication is only natively
   configured for IPv6.  IPv4 may be used as well, but it is being
   encapsulated or translated by means of IPv6.  So from this
   perspective, this device is attached to an IPv6-only link.

2.  Context

   The transition from IPv4 to IPv6 is not something that can be done,
   in the large majority of the cases, overnight and in a single step.
   Consequently, in general, we are unable to talk about a whole network
   having a "single and uniform" status regarding the IPv6 support, at
   least not in the early deployment stages of an operator network.

   Even if possible, it is not frequent to deploy new IPv6 networks
   which have no IPv4 connectivity at all, because at the current phase



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   of the universal goal of the IPv6 deployment, almost every network
   still need to provide some kind of "access" to IPv4 sites.  It is not
   feasible for most of the operators to tell their customers "I can
   provide you IPv6 service, but you will not be able to access all
   Internet contents and apps, because some of them still don't support
   IPv6, so you will miss every content that it is IPv4-only".

   Some networks may have IPv6-only support for specific purposes.  For
   example, a DOCSIS provider may have decided that is worth the effort
   to get rid of IPv4 for the management network of the cable-modems.
   Or a network that provides connectivity only to IoT devices, may be
   IPv6-only.

   However, the "end-networks", in general, need to continue supporting
   IPv4, as there are many devices or apps, in both corporate and end-
   user networks (smartTV, IP cameras, etc.), which are IPv4-only and it
   is not always feasible to update or replace them.

   In IPv6-only access networks, IPv4 support may be provided by
   mechanisms that allow "IPv4-as-a-service" (IPv4aaS, for example by
   means of encapsulation and/or translation on top of IPv6).

3.  Definition of IPv6-only

   Consequently, considering the context described in the section above,
   if we want to be precise and avoid confusing others, we can not use
   the terminology "IPv6-only" in a generic way, and we need to define
   what part of the network we are referring to.

   From that perspective, we define the "IPv6-only" status in a given
   part(s) of a network, depending on if there is actual native
   forwarding of IPv4, so IPv4 is not configured neither managed.

4.  Dual-stack

   This can be applied to a host, router, link, network (part), etc.  It
   means that both, IPv4 and IPv6 are reachable, without specifying how.

5.  Native dual-stack

   This can be applied to a host, router, link, network (part), etc.  It
   means that both, IPv4 and IPv6 are configured/used natively (without
   the need of transition mechanisms).








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6.  IPv6-only network

   IPv6-only can be used only if, a complete network, end-to-end, is
   actually not natively forwarding IPv4, which will mean that no-IPv4
   addresses are configured, neither used for management, neither the
   network is providing transition/translation support, neither there is
   IPv4 transit/peering.

   This is the end of the road of the IPv4-to-IPv6 transition, however
   we aren't there yet, in general at the time of writing this document,
   unless we are referring to special or disconnected (from IPv4)
   networks.

7.  IPv6-only WAN/access

   IPv6-only WAN or access can be used only if the WAN or access network
   isn't actually natively forwarding IPv4.

8.  IPv6-only LAN

   IPv6-only LAN(s) can be used only if the LAN(s), isn't actually
   natively forwarding IPv4.

9.  IPv6-only host/router

   IPv6-only host/router can be used only if the host/router, isn't
   actually using/forwarding IPv4, so IPv4 is unconfigured and/or
   disabled in the external facing interfaces.

   Internal interfaces, such as loopback, can still be using IPv4
   (internally).

10.  Transitional IPv6 host/router

   Transitional IPv6 host/router is a dual-stack host/router with
   IPv6-only WAN where IPv4 service support is provided by means of
   transition mechanism, IPv4aaS (IPv4-as-a-service).

11.  Other cases

   Similar other cases or parts of the network can be considered as
   IPv6-only if there is no actual native forwarding of IPv4 and in that
   case, after "IPv6-only" some word/short text pointing to the specific
   case or part of the network needs to be used.  For instance, we could
   talk about "IPv6-only core" if a core network is only natively
   forwarding IPv6.





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12.  Security Considerations

   This document does not have any specific security considerations.

13.  IANA Considerations

   This document does not have any IANA considerations.

14.  Acknowledgements

   The author would like to acknowledge the inputs from Tim Chown, Noah
   Maina, Lee Howard, Azael Fernandez Alcantara and Marcos Sanz Grosson.

Author's Address

   Jordi Palet Martinez
   The IPv6 Company
   Molino de la Navata, 75
   La Navata - Galapagar, Madrid  28420
   Spain

   Email: jordi.palet@theipv6company.com
   URI:   http://www.theipv6company.com/




























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