Internet Engineering Task Force (IETF)                         G. Huston
Request for Comments: 9637                                         APNIC
Updates: 3849                                                N. Buraglio
Category: Informational                          Energy Sciences Network
ISSN: 2070-1721                                              August 2024


                Expanding the IPv6 Documentation Space

Abstract

  The document describes the reservation of an additional IPv6 address
  prefix for use in documentation.  This update to RFC 3849 expands on
  the existing 2001:db8::/32 address block with the reservation of an
  additional, larger prefix.  The addition of a /20 prefix allows
  documented examples to more closely reflect a broader range of
  realistic, current deployment scenarios and more closely aligns with
  contemporary allocation models for large networks.

Status of This Memo

  This document is not an Internet Standards Track specification; it is
  published for informational purposes.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Not all documents
  approved by the IESG are candidates for any level of Internet
  Standard; see Section 2 of RFC 7841.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  https://www.rfc-editor.org/info/rfc9637.

Copyright Notice

  Copyright (c) 2024 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 Revised BSD License text as described in Section 4.e of the
  Trust Legal Provisions and are provided without warranty as described
  in the Revised BSD License.

Table of Contents

  1.  Introduction
  2.  Requirements Language
  3.  Current Assignment and Allocation Data
  4.  Filtering and Appropriate Use
  5.  Security Considerations
  6.  IANA Considerations
  7.  References
    7.1.  Normative References
    7.2.  Informative References
  Acknowledgments
  Authors' Addresses

1.  Introduction

  [RFC3849] introduced the IPv6 address prefix 2001:db8::/32 as a
  reserved prefix for use in documentation.  The rationale for this
  reservation was to reduce the likelihood of conflict and confusion
  when relating documented examples to deployed systems.

  As the global deployment of IPv6 expands and evolves, individual IPv6
  network deployment scenarios have also increased in size and
  diversity, and there is a requirement for documentation to reflect
  this increased diversity and scope.  The original 2001:db8::/32
  reservation is inadequate to describe many realistic, current
  deployment scenarios.

  Without this additional address allocation, documentation prefixes
  are drawn from address blocks already allocated or assigned to
  existing organizations or well-known ISPs, or they are drawn from the
  currently unallocated address pool.  Such use conflicts with existing
  or future allocations or assignments of IPv6 address space.  The
  reservation of a /20 IPv6 address prefix from the Global Unicast
  Address pool [RFC4291] for documentation purposes allows such
  conflicts to be avoided.

2.  Requirements Language

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
  "OPTIONAL" in this document are to be interpreted as described in
  BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
  capitals, as shown here.

3.  Current Assignment and Allocation Data

  According to the allocation and assignment data published by the
  Regional Internet Registries (RIRs) (see [NROStatsReport]), in August
  2023, 25.9% of the 62,770 recorded IPv6 unicast allocations and
  assignments were larger than a /32 in size.  The most common
  allocation or assignment size was a /29, used in 24.8% of cases.

  The four largest assignments made to end users have been /19s, but
  these allocations were made before the RIRs moved away from the use
  of a fixed /48 site address prefix in IPv6 address assignment
  policies, and in the foreseeable future, it is unlikely that
  individual networks will require more than a /20.  It is believed
  that reservation of a /20 will cover the documentation needs as they
  relate to the broad range of realistic network deployments.

4.  Filtering and Appropriate Use

  Documentation prefixes are for the use of relaying configuration and
  documentation examples, and as such, they MUST NOT be used for actual
  traffic, MUST NOT be globally advertised, and SHOULD NOT be used
  internally for routed production traffic or other connectivity.
  Documentation prefixes should be considered bogon [BOGON] and
  filtered in routing advertisements as appropriate.

5.  Security Considerations

  This special-use prefix should be marked as and considered bogon
  [BOGON].  As is appropriate with bogon prefixes, packets whose source
  or destination belongs to this prefix should be dropped and
  disallowed over the public Internet.

6.  IANA Considerations

  IANA has registered the following in the "IANA IPv6 Special-Purpose
  Address Registry" [IANA-IPv6-SPAR].

  Address Block:  3fff::/20
  Name:  Documentation
  RFC:  RFC 9637
  Allocation Date  2024-07
  Termination Date:  N/A
  Source:  False
  Destination:  False
  Forwardable:  False
  Globally Reachable :  False
  Reserved-by-Protocol:  False

7.  References

7.1.  Normative References

  [IANA-IPv6-SPAR]
             IANA, "IANA IPv6 Special-Purpose Address Registry",
             <https://www.iana.org/assignments/iana-ipv6-special-
             registry>.

  [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119,
             DOI 10.17487/RFC2119, March 1997,
             <https://www.rfc-editor.org/info/rfc2119>.

  [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
             2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
             May 2017, <https://www.rfc-editor.org/info/rfc8174>.

7.2.  Informative References

  [BOGON]    Team Cymru, "Unravelling the Mystery of Bogons: A senior
             stakeholder and IT professional guide", July 2023,
             <https://www.team-cymru.com/post/unravelling-the-mystery-
             of-bogons-a-senior-stakeholder-and-it-professional-guide>.

  [NROStatsReport]
             "NRO Stats Reports",
             <https://ftp.ripe.net/pub/stats/ripencc/nro-stats>.

  [RFC3849]  Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
             Reserved for Documentation", RFC 3849,
             DOI 10.17487/RFC3849, July 2004,
             <https://www.rfc-editor.org/info/rfc3849>.

  [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
             Architecture", RFC 4291, DOI 10.17487/RFC4291, February
             2006, <https://www.rfc-editor.org/info/rfc4291>.

Acknowledgments

  The authors would like to acknowledge the valuable input from XiPeng
  Xiao, Chris Cummings, Russ White, Kevin Myers, Ed Horley, Tom
  Coffeen, and Scott Hogg.

Authors' Addresses

  Geoff Huston
  APNIC
  Email: [email protected]


  Nick Buraglio
  Energy Sciences Network
  Email: [email protected]

You are viewing proxied material from gopher.fnord.one. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.