MBONED Working Group David Meyer
Internet Draft Cisco Systems
Peter Lothberg
Sprint
Category Experimental
draft-ietf-mboned-static-allocation-00.txt May, 1999
Static Allocations in 233/8
1. Status of this Memo
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. Abstract
This describes an experimental policy for use of the class D address
space using 233/8 as the experimental statically assigned subset of
the class D address space. This new experimental allocation is in
addition to those described on [IANA] (e.g. [RFC2365]).
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.
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3. Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
4. Problem Statement
Multicast addresses have traditionally been allocated by a dynamic
mechanism such as SDR [SAP]. However, many current multicast
deployment models are not amenable to dynamic allocation. For
example, many content aggregators require group addresses which are
fixed on a time scale which is not amenable to allocation by a
mechanism such as described in [SAP]. Perhaps more seriously, since
there isn't general consensus by providers, content aggregators, or
application writers as to the allocation mechanism, the Internet is
left without a coherent multicast address allocation scheme.
The MALLOC working group is looking at a specific strategy for global
multicast address allocation [MADCAP, MASC]. This experiment will
proceed in parallel. MADCAP may be employed within AS's, if so
desired.
This document proposes an experimental method of statically
allocating multicast addresses with global scope. This experiment
will last for a period of one year, but may be extended as described
in section 8.
5. Address Space
For purposes of the experiment described here, the IANA should
allocate 233/8. The remaining 24 bits will be administered in a
manner similar to that described in RFC1797:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 233 | 16 bits AS | local bits |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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5.1. Example
Consider, for example, AS 5662. Written in binary, left padded with
0s, we get 0001011000011110. Mapping the high order octet to the
second octet of the address, and the low order octet to the third
octet, we get 233.22.30/24.
6. Allocation
As mentioned above, the allocation proposed here follows the RFC1797
(case 1) allocation scheme, modified as follows: the high order octet
has the value 233, and the next 16 bits are a previously assigned
Autonomous System number (AS), as registered by a network registry
and listed in the RWhois database system. This allows a single /24
per AS.
As was the case with RFC1797, using the AS number in this way allows
the experiment to get underway quickly in that it automatically
allocates some addresses to each service provider and does not
require a registration step.
6.1. Private AS Space
The address space mapped to the private AS space (as defined in
[RFC1930], is reserved for future allocation.
7. Security Considerations
The approach described here may have the effect of reduced exposure
to denial of space attacks based on dynamic allocation. Further,
since dynamic assignment does not cross domain boundaries, well known
intra-domain security techniques can be applied.
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8. IANA Considerations
IANA should allocate 233/8 for experimental assignments. This
assignment should timeout one year after the assignment is made. The
assignment may be renewed at that time. It should be noted that the
experiment described here is in the same spirit the experiment
described in [RFC1797].
9. Acknowledgments
This idea originated with Peter Lothberg's idea that we use the same
allocation (AS based) as described in RFC 1797 in the class D address
space. Randy Bush and Mark Handley contributed many insightful
comments.
10. References
[MADCAP] B. Patel, et. al., "Multicast Address Dynamic Client
Allocation Protocol (MADCAP)",
draft-ietf-malloc-madcap-04.txt, Feburay, 1999.
[MASC] D. Estrin, et. al., "The Multicast Address-Set Claim
(MASC) Protocol", draft-ietf-malloc-masc-01.txt, August,
1998.
[IANA] www.isi.edu/in-notes/iana/assignments/multicast-addresses
[RFC1797] IANA, "Class A Subnet Experiment", RFC 1797, April,
1995.
[RFC1930] J. Hawkinson, et. al., "Guidelines for creation,
selection,
and registration of an Autonomous System (AS)", RFC1930,
March, 1996.
[RFC2365] David Meyer, "Administratively Scoped IP Multicast",
July, 1998.
[RFC2374] R. Hinden, et. al., "An IPv6 Aggregatable Global Unicast
Address Format", July, 1998.
[SAP] Handley, Mark, "SAP: Session Announcement Protocol",
draft-ietf-mmusic-sap-00.txt, November, 1996.
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11. Author's Address
David Meyer
Cisco Systems, Inc.
170 W. Tasman Drive
San Jose, CA 95134-1706
United States
EMail: dmm@cisco.com
Peter Lothberg
Sprint
VARESA0104
12502 Sunrise Valley Drive
Reston VA, 20196
Email: roll@sprint.net
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