Clarification of IPv6 Address Assignment Policy

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Table of Contents

1. Introduction

Internet Protocol Version 6 (IPv6) and its address space are currently defined by [STD86] and [RFC4291]. The management of the IPv6 address space was delegated to IANA by [RFC1881], some years before the current relationship between the IETF and IANA was formalized [RFC2860] and registry details were clarified [RFC7020], [RFC7249].¶

Occasionally, IPv6 address space allocations are performed outside the scope of routine allocations to regional Internet registries. For example, a substantial allocation was requested by an IETF document approved by the IESG [RFC9602], which moved the range 5f00::/16 from the Internet Protocol Version 6 Address Space registry [IANA1] to the IANA IPv6 Special-Purpose Address Registry [IANA3].¶

The allocation policy in the IANA Internet Protocol Version 6 Address Space registry [IANA1] is currently shown as "IESG approval", whereas for major allocations a more stringent policy is appropriate. The present document therefore strengthens the approval level needed for non-routine address allocations, which requires an update to RFC 7249.¶

This document also clarifies the status of RFC 1881. This clarification is necessary because RFC 1881, a joint publication of the IAB and IESG following an IETF Last Call, is incorrectly listed in the RFC index at the time of writing as "legacy", whereas it remains current.¶

2. Approval Level of IPv6 Address Allocations

Portions of the IPv6 address space are shown in the registry as "Reserved by IETF". This is the address space held in reserve for future use if ever the current 125-bit unicast space (2000::/3) is found inadequate or inappropriate.¶

RFC 1881 did not specify an allocation policy for this space. At some point, IANA listed "IESG approval". As defined in [BCP26], this is a rather weak requirement ("Although there is no requirement that the request be documented in an RFC, the IESG has the discretion to request documents...") and is "a fall-back mechanism in the case where one of the other allowable approval mechanisms cannot be employed...".¶

For something as important as the majority of the spare IPv6 address space, the currently defined process is clearly insufficient. The present document replaces the "IESG approval" process by the "IETF Review" process as defined by BCP 26. It is not considered necessary to require the stricter "Standards Action" policy, because there might be cases where opening up a new range of address space did not in fact require a new protocol standard.¶

It may be noted that the recent allocation for [RFC9602], which was processed as a working group document, did indeed follow the more stringent "IETF Review" process proposed by this document. Indeed, the other two related registries [IANA2] [IANA3] do cite the "IETF Review" policy, consistently with RFC 7249.¶

This document therefore extends the first paragraph of section 2.3 of [RFC7249] as follows:¶

OLD:¶

The vast bulk of the IPv6 address space (approximately 7/8ths of the whole address space) is reserved by the IETF [RFC4291], with the expectation that further assignment of globally unique unicast address space will be made from this reserved space in accordance with future needs.¶

NEW:¶

The vast bulk of the IPv6 address space (approximately 7/8ths of the whole address space) is reserved by the IETF [RFC4291], with the expectation that further assignment of globally unique unicast address space will be made from this reserved space in accordance with future needs, through "IETF Review" as defined in [BCP26].¶

3. RFC Editor Considerations

The RFC Editor is requested to update the "Stream" information for [RFC1881] to "IETF" in place of "Legacy".¶

4. IANA Considerations

IANA is requested to update the "Registration Procedure(s)" section of the Internet Protocol Version 6 Address Space registry to show the policy as "IETF Review".¶

5. Security Considerations

The security considerations of [RFC7249] apply. While having no direct security impact, carefully reviewed address allocation mechanisms are necessary to ensure operational address accountability.¶

6. Acknowledgements

Useful comments were received from Dale Carder, Bob Hinden, Scott Kelly, Philipp Tiesel, and others.¶

7. References

Appendix A. Change Log [RFC Editor: please remove]

Authors' Addresses