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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
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].



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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









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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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Full Copyright Statement

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

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
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English.

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Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.



















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