As per Relevance of the word multicast, we have this rfc below:
Network Working Group D.
Request for Comments: 3180 P.
Obsoletes: 2770
BCP: 53 September 2001
Category: Best Current
GLOP Addressing in 233/8
Status of this
This document specifies an Internet Best Current Practices for
Internet Community, and requests discussion and suggestions
improvements. Distribution of this memo is unlimited
Copyright
Copyright (C) The Internet Society (2001). All Rights Reserved
This document defines the policy for the use of 233/8 for
assigned multicast addresses
1.
It is envisioned that the primary use of this space will be many-to
many applications. This allocation is in addition to those
on [IANA] (e.g., [RFC2365]). The IANA has allocated 223/8 as per
2770 [RFC2770]. This document obsoletes RFC 2770.
2. Problem
Multicast addresses have traditionally been allocated by a
mechanism such as SDR [RFC2974]. However, many current
deployment models are not amenable to dynamic allocation.
example, many content aggregators require group addresses that
fixed on a time scale that is not amenable to allocation by
mechanism such as described in [RFC2974]. Perhaps more seriously
since there is not general consensus by providers,
aggregators, or application writers as to the allocation mechanism
the Internet is left without a coherent multicast address
scheme
Meyer & Lothberg Best Current Practice [Page 1]
RFC 3180 GLOP Addressing in 233/8 September 2001
The MALLOC working group has created a specific strategy for
multicast address allocation [RFC2730, RFC2909]. However,
approach has not been widely implemented or deployed. This
proposes a solution for a subset of the problem, namely, those
not covered by Source Specific Multicast
3. Address
The IANA has allocated 223/8 as per RFC 2770 [RFC2770]. RFC 2770
describes the administration of the middle two octets of 233/8 in
manner similar to that described in RFC 1797:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.1.
Consider, for example, AS 5662. Written in binary, left padded
0s, we get 0001011000011110. Mapping the high order octet to
second octet of the address, and the low order octet to the
octet, we get 233.22.30/24.
4.
As mentioned above, the allocation proposed here follows the RFC 1797
(case 1) allocation scheme, modified as follows: the high-order
has the value 233, and the next 16 bits are a previously
Autonomous System number (AS), as registered by a network
and listed in the RWhois database system. This allows a single /24
per AS
As was the case with RFC 1797, using the AS number in this way
automatic assignment of a single /24 to each service provider
does not require an additional registration step
4.1. Private AS
The part of 233/8 that is mapped to the private AS space [RFC1930]
assigned to the IRRs [RFC3138].
5. Large AS
It is important to note that this approach will work only for
octet AS numbers. In particular, it does not work for any AS
extension scheme
Meyer & Lothberg Best Current Practice [Page 2]
RFC 3180 GLOP Addressing in 233/8 September 2001
6. Security
The approach described here may have the effect of reduced
to denial-of-service attacks based on dynamic allocation. Further
since dynamic assignment does not cross domain boundaries, well-
intra-domain security techniques can be applied
7. IANA
The IANA has assigned 233/8 for this purpose
8.
This proposal originated with Peter Lothberg's idea that we use
same allocation (AS based) as described in RFC 1797. Randy Bush
Mark Handley contributed many insightful comments, and Pete
Natalie Whiting contributed greatly to the readability of
document
9.
[IANA] http://www.iana.org/numbers.
[RFC1797] IANA, "Class A Subnet Experiment", RFC 1797, April 1995.
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation
selection, and registration of an Autonomous System (AS)",
RFC 1930, March 1996.
[RFC2365] Meyer, D., "Administratively Scoped IP Multicast",
2365, July 1998.
[RFC2374] Hinden, R., O'Dell, M. and S. Deering, "An IPv
Aggregatable Global Unicast Address Format", RFC 2374,
1998.
[RFC2730] Hanna, S., Patel, B. and M. Shah, "Multicast
Dynamic Client Allocation Protocol (MADCAP)", RFC 2730,
December 1999.
[RFC2770] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8",
2770, February 2000.
[RFC2909] Radoslavov, P., Estrin, D., Govindan, R., Handley, M.,
Kumar, S. and D. Thaler, "The Multicast Address-Set
(MASC) Protocol", RFC 2909, September 2000.
Meyer & Lothberg Best Current Practice [Page 3]
RFC 3180 GLOP Addressing in 233/8 September 2001
[RFC2974] Handley, M., Perkins, C. and E. Whelan, "
Announcement Protocol", RFC 2974, October 2000.
[RFC3138] Meyer, D., "Extended Assignments in 233/8", RFC 3138,
2001.
10. Authors'
David
VARESA0104
12502 Sunrise Valley
Reston VA, 20196
EMail: dmm@sprint.
Peter
VARESA0104
12502 Sunrise Valley
Reston VA, 20196
EMail: roll@sprint.
Meyer & Lothberg Best Current Practice [Page 4]
RFC 3180 GLOP Addressing in 233/8 September 2001
11. Full Copyright
Copyright (C) The Internet Society (2001). All Rights Reserved
This document and translations of it may be copied and furnished
others, and derivative works that comment on or otherwise explain
or assist in its implementation may be prepared, copied,
and distributed, in whole or in part, without restriction of
kind, provided that the above copyright notice and this paragraph
included on all such copies and derivative works. However,
document itself may not be modified in any way, such as by
the copyright notice or references to the Internet Society or
Internet organizations, except as needed for the purpose
developing Internet standards in which case the procedures
copyrights defined in the Internet Standards process must
followed, or as required to translate it into languages other
English
The limited permissions granted above are perpetual and will not
revoked by the Internet Society or its successors or assigns
This document and the information contained herein is provided on
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
Funding for the RFC Editor function is currently provided by
Internet Society
Meyer & Lothberg Best Current Practice [Page 5]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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