Internet DRAFT - draft-albanna-iana-IPv4-mcast-guidelines
draft-albanna-iana-IPv4-mcast-guidelines
Network Working Group Zaid Albanna
INTERNET DRAFT Worldcom
Kevin Almeroth
UCSB
David Meyer
Cisco Systems
Category Best Current Practices
February, 2001
IANA Guidelines for IPv4 Multicast Address Allocation
<draft-albanna-iana-IPv4-mcast-guidelines-00.txt>
1. Status of this Memo
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.
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2. Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
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) 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 to codify existing IANA practice used in the assignment
IPv4 multicast addresses.
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].
In general, due to the relatively small size of the IPv4 multicast
addresses space, further allocation of IPv4 multicast address space
is not recommended. Specifically, the IANA 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 on
http://www.iana.org/cgi-bin/multicast.pl.
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5. Definition of Current Assignment Practice
Unlike IPv4 unicast address assignment, where blocks of addresses are
delegated to regional registries, IPv4 multicast addresses are
assigned directly by the IANA. Current allocations 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 allocates addresses from the Local Network
Control, Internetwork Control, and AD-HOC blocks. Allocation
guidelines for each of these blocks, as well as for the MALLOC,
Source Specific Multicast, GLOP and Administratively Scoped Blocks,
are described below.
Note that while some applications may informally use arbitrary parts
of the IPv4 multicast address space (e.g., 229/8), an application
MUST NOT use address space that is not allocated as described in this
memo.
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. Allocation Guidelines
Allocation of addresses in the Local Network Configuration Block
SHOULD BE be accompanied by a specification ("Specification
Required"). This specification will typically take the form of an
internet draft or RFC.
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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 [RFC1119]) and 224.0.1.68 (mdhcpdisover [RFC2730]).
7.1. Allocation Guidelines
Allocation of addresses in the Internetwork Control block SHOULD BE
accompanied by a specification ("Specification Required"). This
specification will typically take the form of an internet draft or
RFC.
8. AD-HOC Block (224.0.2.0/24 - 224.0.255.0/24)
Addresses in the AD-HOC block have traditionally been allocated 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. Allocation Guidelines
Allocation of addresses in the AD-HOC Block SHOULD BE accompanied by
a specification ("Specification Required").This specification will
typically take the form of an internet draft or RFC. In general, the
IANA SHOULD NOT assign addressing in the AD-HOC Block.
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
via applications like the session directory tool (such as SDR [SDR]).
9.1. Allocation Guidelines
Since addresses in the SDP/SAP block are chosen randomly from the
range of addresses not already in use [RFC2974], no IANA allocation
policy is required. Note that while no additional IANA allocation is
required, addresses in the SDP/SAP block are explicitly for use by
SDP/SAP and MUST NOT be used for other purposes.
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10. MALLOC Block (225/8)
Addresses in the MALLOC block are dynamically allocated by the MALLOC
suite of protocols [RFC2908]. This assignment is temporary and MUST
BE reviewed annually.
10.1. Allocation Guidelines
Since addresses in the MALLOC block are chosen by elements of the
MALLOC architecture, no IANA allocation policy is required. Note that
while no additional IANA allocation is required, addresses in the
MALLOC block are explicitly for allocation by MALLOC servers and MUST
NOT be used for other purposes.
11. Source Specific Multicast Block (232/8)
The Source Specific Multicast (SSM) block use is outlined in [SSM].
In general, 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 where large receiver
audiences require traffic from a small number of well known sources.
11.1. Allocation Guidelines
Because the SSM model essentially makes the entire multicast address
space local to the host, no IANA allocation policy is required. Note,
however, that while no additional IANA allocation 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 allocation is defined in [RFC2770].
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12.1. Allocation Guidelines
Because addresses in the GLOP block are algorithmically preassigned,
no IANA allocation policy is required. Note that while no additional
IANA allocation is required, addresses in the GLOP block are
allocated for use as defined in RFC 2770 and MUST NOT 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. Allocation Guidelines
Since addresses in this block are local to a domain, no IANA
allocation policy is required.
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. An example of an
address block that might be reclaimed is 224.1.0/24 [RFC1190], as
this was an experimental allocation and not in use. In addition,
those allocations in 224.0.1/24 that are not used for Internet-wide
protocol control messages (as described above) above might be
reclaimed.
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, or Administratively Scoped addressing, or
are not globally routed).
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15. Use of IANA Reserved Addresses
Applications MUST NOT use addressing in the IANA reserved blocks.
16. Appeals Process
An applicant that is denied a multicast assignment may ask for
additional consideration of its application. Such appeals SHOULD be
granted only in those cases in which (i). the applicant did not
provide a specification, or (ii). the applicant believes that the
IANA did not understand the technical basis on which the application
rests (and hence the need for assignment of globally scoped
addressing).
16.1. Requirements [RFC2026]
All appeals must include a detailed and specific description of the
facts of the dispute.
All appeals must be initiated within two months of the public
knowledge of the action or decision to be challenged.
At all stages of the appeals process, the individuals or bodies
responsible for making the decisions have the discretion to define
the specific procedures they will follow in the process of making
their decision.
In all cases a decision concerning the disposition of the dispute,
and the communication of that decision to the parties involved, must
be accomplished within a reasonable period of time.
16.2. Process
When an application is appealed, the application (and specification,
if one was provided) is to be reviewed by the IESG, indicating to the
IANA whether the application should be accepted. The IESG MAY
additionally employ Expert Review of the application.
16.2.1. Process Failure
If an applicant should disagree with an action taken by the IANA and
IESG in this process, that application should first try to clairfy
its position with the IANA. If the IANA is unable to satisfy the
applicant, the applicant may ask for its application (and
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specification, if one was provided) to be reviewed by the IAB.
The IAB decision is final with respect to the question of whether an
assignment should be made.
17. Security Considerations
Security issues are not discussed in this memo.
18. Acknowledgments
The authors would like to thank Joe St. Sauver and John Meylor for
their constructive feedback and comments.
19. Author's Address:
Zaid Albanna
Worldcom
22001 Loudoun County Parkway
Ashburn, VA. 20147
Email: zaid@mci.net
Kevin Almeroth
UC Santa Barbara
Sata Barbara, CA.
Email: almeroth@cs.ucsb.edu
David Meyer
Cisco Systems, Inc.
170 Tasman Drive
San Jose, CA, 95134
Email: dmm@cisco.com
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20. References
[IANA] http://www.isi.edu/in-notes/iana/assignments/multicast-addresses
[RFC1190] C. Topolcic, "Experimental Internet Stream
Protocol, Version 2 (ST-II)", RFC 1190, October,
1990.
[RFC1119] Mills, D., "Network Time Protocol (Version 1),
Specification and Implementation", STD 12, RFC 1119,
University of Delaware, July 1988.
[RFC2026] S. Bradner, "The Internet Standards Process --
Revision 3", RFC2026, October 1996.
[RFC2119] S. Bradner, "Key words 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 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/
[SSM] Holbrook, H., and Cain, B., "Source-Specific Multicast
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for IP", draft-holbrook-ssm-arch-01.txt, Work in
progress.
21. 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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the copyright notice or references to the Internet Society or other
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English.
The limited permissions granted above are perpetual and will not be
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TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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