v6ops J. Palet Martinez
Internet-Draft The IPv6 Company
Intended status: Informational October 30, 2017
Expires: May 3, 2018
IPv6-only Terminology Definition
draft-palet-v6ops-ipv6-only-03
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, in reference to what is the
actual functionalities being used (not the actual protocol support).
Status of This Memo
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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 . . . . . . . . . . . . . . . . . . . . . . 3
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 . . . . . . . . . . . . . . . . . . . 4
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
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.
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 IPv6, 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
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
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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 feasible to update or replace them.
In IPv6-only access networks, IPv4 support maybe provided by
mechanisms that allow "IPv4-as-a-service" (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, 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, etc. It means
that both, IPv4 and IPv6 are configured/used natively (without the
need of transition mechanisms).
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.
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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 transporting 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, "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.
12. Security Considerations
This document does not have any specific security considerations.
13. IANA Considerations
This document does not have any IANA considerations.
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14. Acknowledgements
The author would like to acknowledge the inputs from Tim Chown, Noah
Maina, Lee Howard, Azael 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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