Internet DRAFT - draft-palet-v6ops-ipv6-only
draft-palet-v6ops-ipv6-only
v6ops J. Palet Martinez
Internet-Draft The IPv6 Company
Intended status: Informational 23 October 2023
Expires: 25 April 2024
IPv6-only Terminology Definition
draft-palet-v6ops-ipv6-only-06
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
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 25 April 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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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 . . . . . . . . . . . . . . . . . . . . . . 4
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 . . . . . . . . . . . . . . . . . . . . . . . . . 5
12. IPv4 Exclusion . . . . . . . . . . . . . . . . . . . . . . . 5
13. Security Considerations . . . . . . . . . . . . . . . . . . . 5
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 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.
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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
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 or
services. 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. Also if customer
devices in a LAN are IPv4-only, they will not be able to access
IPv6-only services, so this means that IPv6-only services can't be
deployed unless it is done in such way that some transition mechanism
solves that problem as well (example an IPv6-only Data Center,
requires SIIT-DC)
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't 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.
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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).
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).
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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.
12. IPv4 Exclusion
If an IPv6-only network or part of it, has strict filtering rules to
avoid IPv4 to be transported on top of IPv6, this should be
explicitly cited. For example, and enterprise LAN, where employees
can't use VPNs, tunnels, or even translations, could be named as
"IPv6-only LAN with IPv4 Exclusion".
13. Security Considerations
This document does not have any specific security considerations.
14. IANA Considerations
This document does not have any IANA considerations.
15. Acknowledgements
The author would like to acknowledge the inputs from Tim Chown, Noah
Maina, Lee Howard, Azael Fernandez Alcantara and Marcos Sanz Grosson.
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