IPv6 Support Required for all IP-capable nodes
draft-ietf-intarea-ipv6-required-01

Abstract

Given the global lack of available IPv4 space, and limitations in IPv4 extension and transition technologies, this document deprecates the concept that an IP-capable node MAY support IPv4 _only_, and redefines an IP-capable node as one which supports either IPv6 _only_ or IPv4/IPv6 dual-stack. This document updates RFC1812, RFC1122 and RFC4084 to reflect the change in requirements.

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 working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on January 12, 2012.

Copyright Notice

Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 1.1. Requirements Language
• 2. Requirements and Recommendation
• 3. Acknowledgements
• 4. IANA Considerations
• 5. Security Considerations
• 6. References
• 6.1. Normative References
• 6.2. Informative References
• Authors' Addresses

1. Introduction

IP version 4 (IPv4) has served to connect public and private hosts all over the world for over 30 years. However, due to the success of the Internet in finding new and innovative uses for IP networking, billions of hosts are now connected via the Internet and requiring unique addressing. This demand has led to the exhaustion of the IANA global pool of unique IPv4 addresses [IANA-exhaust], and will be followed by the exhaustion of the free pools for each Regional Internet Registry (RIR), the first of which is APNIC [APNIC-exhaust]. While transition technologies and other means to extend the lifespan of IPv4 do exist, nearly all of them come with tradeoffs that prevent them from being optimal long-term solutions when compared with deployment of IP version 6 (IPv6) as a means to allow continued growth on the Internet. See [I-D.ietf-intarea-shared-addressing-issues] and [I-D.donley-nat444-impacts] for some discussion on this topic.

IPv6 [RFC1883] was proposed in 1995 as, among other things, a solution to the limitations on globally unique addressing that IPv4's 32-bit addressing space represented, and has been under continuous refinement and deployment ever since. [RFC2460]. The exhaustion of IPv4 and the continued growth of the internet worldwide has created the driver for widespread IPv6 deployment.

However, the IPv6 deployment necessary to reduce reliance on IPv4 has been hampered by a lack of ubiquitous hardware and software support throughout the industry. Many vendors, especially in the consumer space have continued to view IPv6 support as optional. Even today they are still selling "IP capable" or "Internet Capable" devices which are not IPv6-capable, which has continued to push out the point at which the natural hardware refresh cycle will significantly increase IPv6 support in the average home or enterprise network. They are also choosing not to update existing software to enable IPv6 support on software-updatable devices, which is a problem because it is not realistic to expect that the hardware refresh cycle will single-handedly purge IPv4-only devices from the active network in a reasonable amount of time. This is a significant problem, especially in the consumer space, where the network operator often has no control over the hardware the consumer chooses to use. For the same reason that the average consumer is not making a purchasing decision based on the presence of IPv6 support in their Internet-capable devices and services, consumers are unlikely to replace their still-functional Internet-capable devices simply to add IPv6 support - they don't know or don't care about IPv6, they simply want their devices to work as advertised.

This lack of support is making the eventual IPv6 transition considerably more difficult, and drives the need for expensive and complicated transition technologies to extend the life of IPv4-only devices as well as eventually to interwork IPv4-only and IPv6-only hosts. While IPv4 is expected to coexist on the Internet with IPv6 for many years, a transition from IPv4 as the dominant Internet Protocol towards IPv6 as the dominant Internet Protocol will need to occur. The sooner the majority of devices support IPv6, the less protracted this transition period will be.

1.1. 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 RFC 2119 [RFC2119].

2. Requirements and Recommendation

This draft updates the following documents:

Updates [RFC1812], especially sections 1, 2, and 4 which use the generic "IP" synonymously with the more specific "IPv4." Since RFC1812 is an IPv4 router specification, the generic use of IP in this standard may cause confusion as IP is redefined to mean IPv4 + IPv6. This proposed update is not intended to change the existing technical interpretation of RFC1812 to include IPv6 in its implementation details. Rather, it is intended to ensure that those using RFC1812 as a guideline for IP implementations understand that IP nodes SHOULD NOT support IPv4 only, and that they should use the other informative references in this document as a companion guideline for proper IPv6 implementations.

Updates [RFC1122] to clarify that this document, especially in section 3, primarily discusses IPv4 where it uses the more generic term "IP" and is no longer a complete definition of "IP" or the Internet Protocol suite by itself. For example, section 3.1 does not contain references to the IPv6 equivalent standards for the Internet layer, section 3.2 is a protocol walk-through for IPv4 only; section 3.2.1.1 explicitly requires an IP datagram whose version number is not 4 to be discarded, which would be detrimental to IPv6 forwarding. However, portions of RFC1122 refer to the Internet Layer and IP more in terms of its function and are less version-specific, such as Section 1.1.3. In these cases, it is possible to redefine generic "IP" support to include and require IPv6 for IP-capable nodes and routers.

Updates [RFC4084] to move "Version Support" from Section 4, "Additional Terminology" to Section 2, "General Terminology." This is to reflect the idea that version support is now critical to defining the types of IP service, especially with respect to Full Internet Connectivity.

Rather than update the existing IPv4 protocol specification standards to include IPv6, IETF has defined a completely separate set of standalone documents which cover IPv6. Therefore, the above-listed standards are not being updated to include the complete technical details of IPv6, but to identify that a distinction must be made between IPv4 and IPv6 in some places where IP is used generically. Current requirements for IPv6 support can be found in [RFC4294], soon to be updated by [I-D.ietf-6man-node-req-bis] and in [RFC6204]. Each of these documents contains specific information, requirements, and references to other draft and proposed standards governing many aspects of IPv6 implementation.

From a practical perspective, the requirements proposed by this draft mean that:

• New IP implementations MUST support IPv6.
• Current IP implementations SHOULD support IPv6.
• IPv6 support MUST be equivalent or better in quality and functionality when compared to IPv4 support in an IP implementation.
• Current and new IP Networking implementations SHOULD support IPv4 and IPv6 coexistence (dual-stack), but MUST NOT require IPv4 for proper and complete function.
• It is expected that many existing devices and implementations will not be able to support IPv6 for one or more valid technical reasons, but for maximum flexibility and compatibility, a best effort SHOULD be made to update existing hardware and software to enable IPv6 support.

3. Acknowledgements

Thanks to the following people for their reviews and comments: Marla Azinger, Brian Carpenter, Victor Kuarsingh, Jari Arkko, Scott Brim, Margaret Wasserman, Joe Touch, Fred Baker, Benson Schliesser

4. IANA Considerations

This memo includes no request to IANA.

5. Security Considerations

There are no direct security considerations generated by this document, but existing documented security considerations for implementing IPv6 will apply.

6. References

6.1. Normative References

6.2. Informative References

Authors' Addresses