One document matched: draft-ymbk-no-subnet-anycast-00.txt

Network Working Group                                            R. Bush
Internet-Draft                                 Internet Initiative Japan
Obsoletes: 2526 (if approved)                               July 4, 2011
Intended status: Standards Track
Expires: January 5, 2012


                     IPv6 Subnet Anycast Deprecated
                    draft-ymbk-no-subnet-anycast-00

Abstract

   IPv6 Subnet Anycast is not used operationally, complicates
   implementations, and complicates protocol specifications.  The form
   of anycast actually used in the Internet is routing-based, and is
   essentilly the same as that of IPv4 anycast.  Therefore, this
   document deprecates IPv6 Subnet Anycast.

   This is an early draft and will require non-trivial fill-in and
   details.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.  This document may not be modified,
   and derivative works of it may not be created, and it may not be
   published except as an Internet-Draft.

   Internet-Drafts are working documents of the Internet Engineering
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on January 5, 2012.

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
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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   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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Security Considerations . . . . . . . . . . . . . . . . . . . . 3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . . . 4
     5.2.  Informative References  . . . . . . . . . . . . . . . . . . 4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 4

































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1.  Introduction

   The form of anycast which is used in the operational internet is
   described in [RFC4786].  This is used widely in IPv4 and IPv6.  To
   quote,

      "To distribute a service using anycast, the service is first
      associated with a stable set of IP addresses, and reachability to
      those addresses is advertised in a routing system from multiple,
      independent service nodes."

   IPv6 subnet anycast, as defined in [RFC2526], complicates host and
   router stacks.  It also makes address assignment needlessly complex,
   see [RFC6164].

   IPv6 Subnet Anycast is not actually used or deployed.  In this case,
   it is fairly certain that implementations are not even debugged.

   As IPv6 becomes more widely deployed, having special unused code in
   the critical code path is unnecessary, unwise, and invites bugs and
   inefficiency.

   There is no need for reserved subnet anycast addresses, because any
   address can be an anycast address.  Only the node where an anycast
   address is configured needs to know that it is an anycast address.
   That is, there is no need to be able to recognise such an address
   from its format.  The use of IPv4 anycast has not been impeded by the
   inability to tell an anycast address from an ordinary address.

   Therefore, this document deprecates IPv6 Subnet Anycast addresses and
   removes the relevance conformance requirements from host and router
   implementations.


2.  Security Considerations

   There are no known security implications for this document.  It
   probably reduces vulnerabilities.


3.  IANA Considerations

   This document asks nothing of the IANA.


4.  Acknowledgments

   The author wishes to thank Karl Auer.



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5.  References

5.1.  Normative References

   [RFC2526]  Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast
              Addresses", RFC 2526, March 1999.

5.2.  Informative References

   [RFC4786]  Abley, J. and K. Lindqvist, "Operation of Anycast
              Services", BCP 126, RFC 4786, December 2006.

   [RFC6164]  Kohno, M., Nitzan, B., Bush, R., Matsuzaki, Y., Colitti,
              L., and T. Narten, "Using 127-Bit IPv6 Prefixes on Inter-
              Router Links", RFC 6164, April 2011.


Author's Address

   Randy Bush
   Internet Initiative Japan
   5147 Crystal Springs
   Bainbridge Island, Washington  98110
   US

   Phone: +1 206 780 0431 x1
   Email: randy@psg.com
























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