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 (C) The Internet Society (2001). All Rights Reserved.
This memo provides describes the mapping of the GLOP addresses
corresponding to the private AS space.
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 <email@example.com>
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
Meyer Informational [Page 1]RFC 3138 Extended Assignments in 233/8 June 20012. 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 (220.127.116.11 -
18.104.22.168) 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
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
Kurt Kayser, Mirjam Kuehne, Michelle Schipper and Randy Bush provided
many insightful comments on earlier versions of this document.
6. Author's Address
12502 Sunrise Valley Dr
Reston VA, 20191
Meyer Informational [Page 2]RFC 3138 Extended Assignments in 233/8 June 20017. References
[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,
[RFC2365] Meyer, D., "Administratively Scoped IP Multicast",
RFC 2365, July 1998.