Internet Engineering Task Force (IETF) T. Narten
Request for Comments: 6177 IBM
BCP: 157 G. Huston
Obsoletes: 3177 APNIC
Category: Best Current Practice L. Roberts
ISSN: 2070-1721 Stanford University
March 2011
IPv6 Address Assignment to End Sites
Abstract
RFC 3177 argued that in IPv6, end sites should be assigned /48 blocks
in most cases. The Regional Internet Registries (RIRs) adopted that
recommendation in 2002, but began reconsidering the policy in 2005.
This document obsoletes the RFC 3177 recommendations on the
assignment of IPv6 address space to end sites. The exact choice of
how much address space to assign end sites is an issue for the
operational community. The IETF's role in this case is limited to
providing guidance on IPv6 architectural and operational
considerations. This document reviews the architectural and
operational considerations of end site assignments as well as the
motivations behind the original recommendations in RFC 3177.
Moreover, this document clarifies that a one-size-fits-all
recommendation of /48 is not nuanced enough for the broad range of
end sites and is no longer recommended as a single default.
This document obsoletes RFC 3177.
Status of This Memo
This memo documents an Internet Best Current Practice.
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). Further information on
BCPs is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6177.
Narten, et al. Best Current Practice [Page 1]
RFC 6177 IPv6 Address Assignment to End Sites March 2011
Copyright Notice
Copyright (c) 2011 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
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Without obtaining an adequate license from the person(s) controlling
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it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
1. Introduction ....................................................3
2. On /48 Assignments to End Sites .................................4
3. Other RFC 3177 Considerations ...................................6
4. Impact on IPv6 Standards ........................................6
4.1. RFC 3056: Connection of IPv6 Domains via IPv4 Clouds .......6
4.2. IPv6 Multicast Addressing ..................................7
5. Summary .........................................................7
6. Security Considerations .........................................8
7. Acknowledgments .................................................8
8. Informative References ..........................................8
Narten, et al. Best Current Practice [Page 2]
RFC 6177 IPv6 Address Assignment to End Sites March 2011
1. Introduction
There are a number of considerations that factor into address
assignment policies. For example, to provide for the long-term
health and scalability of the public routing infrastructure, it is
datatracker.ietf.org