wdiff draft-ietf-mboned-iana-ipv4-mcast-guidelines-03.txt draft-ietf-mboned-iana-ipv4-mcast-guidelines-04.txt

Network Working Group Zaid Albanna
INTERNET DRAFT Juniper Networks
Kevin Almeroth
UCSB
David Meyer
Sprint
Michelle Schipper
IANA
Category Best Current Practices
June, 2001A new Request for Comments is now available in online RFC libraries.

BCP 51
RFC 3171

Title: IANA Guidelines for IPv4 Multicast Address
Assignments
<draft-ietf-mboned-iana-ipv4-mcast-guidelines-03.txt>

1. Status of this Memo
Author(s): Z. Albanna, K. Almeroth, D. Meyer, M. Schipper
Status: Best Current Practice
Date: August 2001
Mailbox: zaid@juniper.net, almeroth@cs.ucsb.edu,
dmm@sprint.net, iana@iana.org
Pages: 8
Characters: 15389
Updates/Obsoletes/SeeAlso: None

I-D Tag: draft-ietf-mboned-iana-ipv4-mcast-guidelines-04.txt

URL: ftp://ftp.rfc-editor.org/in-notes/rfc3171.txt

This memo provides guidance for the Internet Assigned Numbers
Authority (IANA) in assigning IPv4 multicast addresses.

This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.

This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026.

Internet Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.

The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

2. Copyright Notice

3. Abstract

This memo provides guidance for the IANA in assigning IPv4 multicast
addresses.

4. Introduction

The Internet Assigned Numbers Authority (IANA) (www.iana.org) announcement is
charged with allocating parameter values for fields in protocols
which have been designed, created or are maintained by the Internet
Engineering Task Force (IETF). RFC 2780 [RFC2780] provides the IANA
guidance in the assignment of parameters for fields in newly
developed protocols. This memo expands on section 4.4.2 of RFC 2780
and attempts sent to codify existing IANA practice used in the assignment
IPv4 multicast addresses.

The terms "Specification Required", "Expert Review", "IESG Approval",
"IETF Consensus", IETF list 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 RFC-DIST list.
Requests to be interpreted as defined in RFC 2119
[RFC2119].

In general, due added to or deleted from the relatively small size of the IPv4 multicast
addresses space, further assignment of IPv4 multicast address space
is recommended only in limited circumstances. Specifically, the IANA IETF distribution list
should only assign addresses in those cases where the dynamic
selection (SDP/SAP), GLOP, SSM or Administratively Scoped address
spaces cannot be used. The guidelines described below are reflected
in http://www.iana.org/assignments/multicast-addresses.

5. Definition of Current Assignment Practice

Unlike IPv4 unicast address assignment, where blocks of addresses are
delegated sent to regional registries, IPv4 multicast addresses are
assigned directly by the IANA. Current assignments appear as follows
[IANA]:

224.0.0.0 - 224.0.0.255 (224.0.0/24) Local Network Control Block
224.0.1.0 - 224.0.1.255 (224.0.1/24) Internetwork Control Block
224.0.2.0 - 224.0.255.0 AD-HOC Block
224.1.0.0 - 224.1.255.255 (224.1/16) ST Multicast Groups
224.2.0.0 - 224.2.255.255 (224.2/16) SDP/SAP Block
224.252.0.0 - 224.255.255.255 DIS Transient Block
225.0.0.0 - 225.255.255.255 (225/8) MALLOC Block
226.0.0.0 - 231.255.255.255 RESERVED
232.0.0.0 - 232.255.255.255 (232/8) Source Specific Multicast Block
233.0.0.0 - 233.255.255.255 (233/8) GLOP Block
234.0.0.0 - 238.255.255.255 RESERVED
239.0.0.0 - 239.255.255.255 (239/8) Administratively Scoped Block

The IANA generally assigns addresses from the Local Network Control,
Internetwork Control, and AD-HOC blocks. Assignment guidelines for
each of these blocks, as well as for the MALLOC, Source Specific
Multicast, GLOP and Administratively Scoped Blocks, are described
below.

6. Local Network Control Block (224.0.0/24)

Addresses in the Local Network Control block are used for protocol
control traffic that is not forwarded off link. Examples of this type
of use include OSPFIGP All Routers (224.0.0.5) [RFC2328].

6.1. Assignment Guidelines

Pursuant IETF-REQUEST@IETF.ORG. Requests to section 4.4.2 of RFC 2780 [RFC2780], assignments from the
Local Network Control block follow an Expert Review, IESG Approval or
Standards Action process. See [IANA] for the current set of
assignments.

7. Internetwork Control Block (224.0.1/24)

Addresses in the Internetwork Control block are used for protocol
control that must be forwarded through the Internet. Examples include
224.0.1.1 (NTP [RFC2030]) and 224.0.1.68 (mdhcpdisover [RFC2730]).

7.1. Assignment Guidelines

Pursuant
added to section 4.4.2 of RFC 2780 [RFC2780], assignments from the
Internetwork Control block follow an Expert Review, IESG Approval or
Standards Action process. See [IANA] for the current set of
assignments.

8. AD-HOC Block (224.0.2.0/24 - 224.0.255.0/24)

Addresses in the AD-HOC block have traditionally been assigned for
those applications that don't fit in either the Local or Internetwork
Control blocks. These addresses are globally routed and are typically
used by applications that require small blocks of addressing (e.g.,
less than a /24).

8.1. Assignment Guidelines

In general, the IANA SHOULD NOT assign addressing in the AD-HOC
Block. However, the IANA may under special special circumstances,
assign addressing deleted from this block. Pursuant to section 4.4.2 of RFC
2780 [RFC2780], assignments from the AD-HOC block follow an Expert
Review, IESG Approval or Standards Action process. See [IANA] for the
current set of assignments.

9. SDP/SAP Block (224.2/16)

Addresses in the SDP/SAP block are used by applications that receive
addresses through the Session Announcement Protocol [RFC2974] for use RFC-DIST distribution list should
be sent to RFC-DIST-REQUEST@RFC-EDITOR.ORG.

Details on obtaining RFCs via applications like the session directory tool (such as SDR [SDR]).

9.1. Assignment Guidelines

Since addresses in the SDP/SAP block are chosen randomly from the
range of addresses not already in use [RFC2974], no IANA assignment
policy is required. Note that while no additional IANA assignment is
required, addresses in the SDP/SAP block are explicitly for use by
SDP/SAP and MUST NOT FTP or EMAIL may be used for other purposes.

10. MALLOC Block (225/8)

Addresses in the MALLOC block are dynamically assigned by the MALLOC
suite of protocols [RFC2908]. This assignment is temporary and MUST
BE reviewed annually.

10.1. Assignment Guidelines

Since addresses in the MALLOC block are chosen by elements of the
MALLOC architecture, no IANA assignment policy is required. Note that
while no additional IANA assignment is required, addresses in the
MALLOC block are explicitly for assignment obtained by MALLOC servers and MUST
NOT be used for other purposes.

11. Source Specific Multicast Block (232/8)

The Source Specific Multicast (SSM) is sending
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.

11.1. Assignment Guidelines

Because the SSM model essentially makes the entire multicast address
space local EMAIL message to rfc-info@RFC-EDITOR.ORG with the host, no IANA assignment policy is required. Note,
however, that while no additional IANA assignment is required,
addresses in the SSM block are explicitly for use by SSM and MUST NOT
be used for other purposes.

12. GLOP Block (233/8)

Addresses in the GLOP block are globally scoped statically assigned
addresses. The assignment is made by mapping a domain's autonomous
system number into the middle two octets of 233.X.Y.0/24. The mapping
and assignment is defined in [RFC2770].

12.1. Assignment Guidelines

Because addresses in the GLOP block are algorithmically preassigned,
no IANA assignment policy is required. Note that while no additional
IANA assignment is required, addresses in the GLOP block are assigned message body
help: ways_to_get_rfcs. For example:

To: rfc-info@RFC-EDITOR.ORG
Subject: getting rfcs

help: ways_to_get_rfcs

Requests for use as defined in RFC 2770 and MUST NOT special distribution should be used for other
purposes.

13. Administratively Scoped Address Block (239/8)

Addresses in the Administratively Scoped Address block are for local
use within a domain and are described in [RFC2365].

13.1. Assignment Guidelines

Since addresses in this block are local addressed to a domain, no IANA
assignment policy is required.

13.1.1. Relative Offsets

The relative offsets [RFC2365] are used to ensure that a service can
be located independent of the extent of the enclosing scope (see RFC
2770 for details). Since there are only 256 such offsets, either the IANA
should only assign a relative offset to a protocol that provides an
infra-structure supporting service. Examples
author of such services include the Session Announcement Protocol [RFC2974]. Pursuant to section
4.4.2 of RFC 2780 [RFC2780], assignments of Relative Offsets follow
an Expert Review, IESG Approval or Standards Action process. See
[IANA] for the current set of assignments.

14. Annual Review

Given the dynamic nature of IPv4 multicast and its associated infra-
structure, and the previously undocumented IPv4 multicast address
assignment guidelines, the IANA should conduct an annual review of
currently assigned addresses.

14.1. Address Reclamation

During the review described above, addresses that were mis-assigned
should, where possible, be reclaimed or reassigned.

The IANA should also review assignments in the AD-HOC, DIS Transient
Groups, and ST Multicast Groups blocks and reclaim those addresses
that are not in use on the global Internet (i.e, those applications
which can use SSM, GLOP, question, or Administratively Scoped addressing, or
are not globally routed).

15. Use of IANA Reserved Addresses

Applications MUST NOT use addressing in the IANA reserved blocks.

16. Appeals Process

Appeals of this process are to be handled in accordance with Section
6.5 of RFC 2026 [RFC2026].

17. Security Considerations

The assignment guidelines described in this document do not alter the
security properties of either RFC-Manager@RFC-EDITOR.ORG. Unless
specifically noted otherwise on the Any Source or Source Specific
multicast service models.

18. Acknowledgments

The authors would like to thank Joe St. Sauver, John Meylor, Randy
Bush, and Thomas Narten for their constructive feedback and comments.

19. Author's Address:

Zaid Albanna
1149 N. Mathilda Ave
Sunnyvale, CA. 94089
zaid@juniper.net

Kevin Almeroth
UC Santa Barbara
Santa Barbara, CA.
Email: almeroth@cs.ucsb.edu

David Meyer
Sprint E|Solutions
Email: dmm@sprint.net

Michelle Schipper
IANA Administrator
Internet Assigned Numbers Authority
4676 Admiralty Way, Suite 330
Marina del Rey, CA 90292
iana@iana.org

20. References

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

[RFC1190] C. Topolcic, "Experimental Internet Stream
Protocol, Version 2 (ST-II)", RFC 1190, October,
1990.

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

[RFC2030] Mills, D., Simple Network Time Protocol (SNTP) Version 4 itself, all RFCs are for IPv4, IPv6 and OSI", D. Mills, October 1996.

[RFC2119] S. Bradner, "Key words
unlimited distribution.echo
Submissions for use in RFCs to
Indicate Requirement Levels", RFC 2119, March,
1997.

[RFC2328] J. Moy,"OSPF Version 2", RFC 2328, April, 1998.

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

[RFC2434] Narten, T. and H. Alvestrand, "Guidelines Requests for
Writing an IANA Considerations Section in RFCs",
BCP 26, RFC 2434, October 1998.

[RFC2730] Hanna, S., Patel, B. and M. Shah, "Multicast Address
Dynamic Client Allocation Protocol (MADCAP), December
1999.

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

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

[RFC2908] D. Thaler, M. Handley, D.Estrin, "Theh Internet Multicast
Address Allocation Architecture", RFC 2908, September 2000.

[RFC2974] M. Handley, C. Perkins, E. Whelan, "Session
Announcement Protocol", RFC 2974, October 2000.

[SDR] http://www.aciri.org/sdr/

21. Full Copyright Statement

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or assist in its implementation may be prepared, copied, published
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RFC-EDITOR@RFC-EDITOR.ORG. Please consult RFC 2223, Instructions to the Internet Society or other
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