Re: subnet router anycast

[Randy Bush <[e-mail]>]

Network Working Group                                            R. Bush
Internet-Draft                                                       IIJ
Intended status: Standards Track                             August 2010
Expires: February 2, 2011


                     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.

Status of this Memo

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   This Internet-Draft will expire on February 2, 2011.

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   the Trust Legal Provisions and are provided without warranty as
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Security Considerations . . . . . . . . . . . . . . . . . . . . 3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
   4.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     4.1.  Normative References  . . . . . . . . . . . . . . . . . . . 3
     4.2.  Informative References  . . . . . . . . . . . . . . . . . . 3
   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 unnecessarily
   complex, see [I-D.kohno-ipv6-prefixlen-p2p].

   IPv6 subnet anycast is not actually used or deployed.  In this case,
   it is sure that implementations are not even debugged.

   Therefore, this document deprecates IPv6 subnet anycast and removes
   conformance requirements from host and router implementations.


2.  Security Considerations

   There are no known security implications for this document.


3.  IANA Considerations

   This document has no IANA Considerations.


4.  References

4.1.  Normative References

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

4.2.  Informative References

   [I-D.kohno-ipv6-prefixlen-p2p]
              Kohno, M., Nitzan, B., Bush, R., Matsuzaki, Y., and L.
              Colitti, "Using 127-bit IPv6 Prefixes on Inter-Router
              Links", draft-kohno-ipv6-prefixlen-p2p-02 (work in
              progress), July 2010.

   [RFC4786]  Abley, J. and K. Lindqvist, "Operation of Anycast



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              Services", BCP 126, RFC 4786, December 2006.


Author's Address

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

   Phone: [phone] x1
   Email: [e-mail]






































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