Network Working Group                                           D. Meyer
Request for Comments: 3138                                        Sprint
Category: Informational                                        June 2001


                     Extended Assignments in 233/8

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This memo provides describes the mapping of the GLOP addresses
   corresponding to the private AS space.

1. Introduction

   RFC 2770 [RFC2770] describes an experimental policy for use of the
   class D address space using 233/8.  The technique described there
   maps 16 bits of Autonomous System number (AS) into the middle two
   octets of 233/8 to yield a /24.  While this technique has been
   successful, the assignments are inefficient in those cases in which a
   /24 is too small or the user doesn't have its own AS.

   RFC 1930 [RFC1930] defines the private AS space to be 64512 through
   65535.  This memo expands on RFC 2770 to allow routing registries to
   assign multicast addresses from the GLOP space corresponding to the
   RFC 1930 private AS space.  This space will be referred to as the
   EGLOP (Extended GLOP) address space.

   This memo is a product of the Multicast Deployment Working Group
   (MBONED) in the Operations and Management Area of the Internet
   Engineering Task Force.  Submit comments to <mboned@ns.uoregon.edu>
   or the authors.

   The terms "Specification Required", "Expert Review", "IESG Approval",
   "IETF Consensus", and "Standards Action", are used in this memo to
   refer to the processes described in [RFC2434].  The keywords MUST,
   MUST NOT, MAY, OPTIONAL, REQUIRED, RECOMMENDED, SHALL, SHALL NOT,
   SHOULD, SHOULD NOT are to be interpreted as defined in RFC 2119
   [RFC2119].

2. Overview

   http://www.iana.org/assignments/multicast-addresses defines a
   mechanism for assignment of multicast addresses that are generally
   for use in network control applications.  It is envisioned that those
   addresses assigned from the EGLOP space (233.252.0.0 -
   233.255.255.255) will be used by applications that cannot use
   Administratively Scoped Addressing [RFC2365], GLOP Addressing
   [RFC2770], or Source Specific Multicast (Source Specific Multicast,
   or SSM, is an extension of IP Multicast in which traffic is forwarded
   to receivers from only those multicast sources for which the
   receivers have explicitly expressed interest, and is primarily
   targeted at one-to-many (broadcast) applications).

3. Assignment Criteria

   Globally scoped IPv4 multicast addresses in the EGLOP space are
   assigned by a Regional Registry (RIR).  An applicant MUST, as per
   [IANA], show that the request cannot be satisfied using
   Administratively Scoped addressing [RFC2365], GLOP addressing
   [RFC2770], or SSM.  The fine-grained assignment policy is left to the
   assigning RIR.

4. Security Considerations

   The assignment scheme described in this document does not effect the
   security properties of the the single source or any source multicast
   service models.

5. Acknowledgments

   Kurt Kayser, Mirjam Kuehne, Michelle Schipper and Randy Bush provided
   many insightful comments on earlier versions of this document.

6. Author's Address

   David Meyer
   Sprint
   12502 Sunrise Valley Dr
   Reston VA,  20191

   EMail: dmm@sprint.net

7. References

   [IANA]          http://www.iana.org/assignments/multicast-addresses

   [RFC1930]       Hawkinson J. and T. Bates, "Guidelines for
                   creation, selection, and registration of an
                   Autonomous System (AS)", RFC 1930, March 1996.

   [RFC2026]       Bradner, S., "The Internet Standards Process --
                   Revision 3", BCP 9, RFC 2026, October 1996.

   [RFC2119]       Bradner, S., "Key words for use in RFCs to
                   Indicate Requirement Levels", BCP 14, RFC 2119,
                   March 1997.

   [RFC2365]       Meyer, D., "Administratively Scoped IP Multicast",
                   RFC 2365, July 1998.

   [RFC2770]       Meyer, D. and P. Lothberg, "GLOP Addressing in
                   233/8", RFC 2770, February 2000.

   [RFC2780]       Bradner, S. and V. Paxson, "IANA Allocation
                   Guidelines For Values In the Internet Protocol
                   and Related Headers", BCP 37, RFC 2780, March
                   2000.

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