draft-ietf-mboned-ipv4-uni-based-mcast-02.txt   draft-ietf-mboned-ipv4-uni-based-mcast-03.txt 
Network Working Group Dave Thaler Network Working Group D. Thaler
Internet-Draft Microsoft Internet-Draft Microsoft
Expires: April 2005 October 18, 2004 Expires: September 5, 2007 March 4, 2007
Unicast-Prefix-based IPv4 Multicast Addresses Unicast-Prefix-based IPv4 Multicast Addresses
<draft-ietf-mboned-ipv4-uni-based-mcast-02.txt> draft-ietf-mboned-ipv4-uni-based-mcast-03.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, each author represents that any
patent or other IPR claims of which I am aware have been applicable patent or other IPR claims of which he or she is aware
disclosed, or will be disclosed, and any of which I become aware have been or will be disclosed, and any of which he or she becomes
will be disclosed, in accordance with RFC 3668. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six Internet-Drafts are draft documents valid for a maximum of six months
months and may be updated, replaced, or obsoleted by other and may be updated, replaced, or obsoleted by other documents at any
documents at any time. It is inappropriate to use Internet- time. It is inappropriate to use Internet-Drafts as reference
Drafts as reference material or to cite them other than as "work material or to cite them other than as "work in progress."
in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on September 5, 2007.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The IETF Trust (2007).
Abstract Abstract
This specification defines an extension to the multicast This specification defines an extension to the multicast addressing
addressing architecture of the IP Version 4 protocol. The architecture of the IP Version 4 protocol. The extension presented
extension presented in this document allows for unicast-prefix- in this document allows for unicast-prefix-based allocation of
based allocation of multicast addresses. By delegating multicast multicast addresses. By delegating multicast addresses at the same
addresses at the same time as unicast prefixes, network operators time as unicast prefixes, network operators will be able to identify
will be able to identify their multicast addresses without needing their multicast addresses without needing to run an inter-domain
to run an inter-domain allocation protocol. allocation protocol.
1. Introduction
RFC 3180 [GLOP] defined an experimental allocation mechanism in
233/8 whereby an Autonomous System (AS) number is embedded in the
middle 16 bits of an IPv4 multicast address, resulting in 256
multicast addresses per AS. Advantages of this mechanism include
the ability to get multicast address space without an inter-domain
multicast address allocation protocol, and the ease of determining
the AS of the owner of an address for debugging and auditing
purposes.
Some disadvantages of GLOP include: Table of Contents
o there is work in progress [AS4B] on expanding the size of an 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
AS number to 4 bytes, and GLOP cannot work with such AS's. 2. Address Space . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
5. Informative References . . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5
Intellectual Property and Copyright Statements . . . . . . . . . . 6
o when an AS covers multiple sites or organizations, 1. Introduction
administration of the multicast address space within an AS
must be handled by other mechanisms, such as manual
administrative effort or MADCAP [MADCAP].
o during debugging, identifying the AS does not immediately RFC 3180 [RFC3180] defined an experimental allocation mechanism
identify the owning organization, when an AS covers multiple (called "GLOP") in 233/8 whereby an Autonomous System (AS) number is
organizations. embedded in the middle 16 bits of an IPv4 multicast address,
resulting in 256 multicast addresses per AS. Advantages of this
mechanism include the ability to get multicast address space without
an inter-domain multicast address allocation protocol, and the ease
of determining the AS of the owner of an address for debugging and
auditing purposes.
Some disadvantages of GLOP include:
o there is work in progress [AS4B] on expanding the size of an AS
number to 4 bytes, and GLOP cannot work with such AS's.
o when an AS covers multiple sites or organizations, administration
of the multicast address space within an AS must be handled by
other mechanisms, such as manual administrative effort or MADCAP
[RFC2730].
o during debugging, identifying the AS does not immediately identify
the owning organization, when an AS covers multiple organizations.
o only 256 addresses are automatically available per AS, and o only 256 addresses are automatically available per AS, and
obtaining any more requires administrative effort. obtaining any more requires administrative effort.
More recently, a mechanism [V6UPBM] has been developed for IPv6 More recently, a mechanism [RFC3306] has been developed for IPv6
which provides a multicast range to every IPv6 subnet, which is at which provides a multicast range to every IPv6 subnet, which is at a
a much finer granularity than an AS. As a result, the first three much finer granularity than an AS. As a result, the first three
disadvantages above are avoided (and the last disadvantage does disadvantages above are avoided (and the last disadvantage does not
not apply to IPv6 due to the extended size of the address space). apply to IPv6 due to the extended size of the address space).
Another advantage of providing multicast space to every subnet Another advantage of providing multicast space to every subnet
(rather than just to an entire AS) is that multicast address (rather than just to an entire AS) is that multicast address
allocation within the range need only be coordinated within the allocation within the range need only be coordinated within the
subnet. subnet.
This draft specifies a mechanism similar to [V6UPBM], whereby a This draft specifies a mechanism similar to [RFC3306], whereby a
range of IPv4 multicast address space is provided to most IPv4 range of IPv4 multicast address space is provided to most IPv4
subnets. A resulting advantage over GLOP is that the mechanisms subnets. A resulting advantage over GLOP is that the mechanisms in
in IPv4 and IPv6 become more similar. IPv4 and IPv6 become more similar.
This document proposes an experimental method of statically This document proposes an experimental method of statically
allocating multicast addresses with global scope. As described in allocating multicast addresses with global scope. As described in
section 4, this experiment will last for a period of one year, but section Section 4, this experiment will last for a period of one
may be extended. year, but may be extended.
2. Address Space 2. Address Space
(RFC-editor: replace TBD below with IANA-assigned value, and (RFC-editor: replace TBD below with IANA-assigned value, and delete
delete this note.) this note.)
A multicast address with the prefix TBD/8 indicates that the A multicast address with the prefix TBD/8 indicates that the address
address is a Unicast-Based Multicast (UBM) address. The is a Unicast-Based Multicast (UBM) address. The remaining 24 bits
remaining 24 bits can be used as follows: can be used as follows:
Bits: | 8 | Unicast Prefix Length | 24 - Unicast Prefix Length | Bits: | 8 | Unicast Prefix Length | 24 - Unicast Prefix Length |
+-----+-----------------------+----------------------------+ +-----+-----------------------+----------------------------+
Value: | TBD | Unicast Prefix | Group ID | Value: | TBD | Unicast Prefix | Group ID |
+-----+-----------------------+----------------------------+ +-----+-----------------------+----------------------------+
For subnets with a /24 or shorter prefix, the unicast prefix of For subnets with a /24 or shorter prefix, the unicast prefix of the
the subnet is appended to the common /8. Any remaining bits may subnet is appended to the common /8. Any remaining bits may be
be locally assigned by hosts within the link (e.g., using manual locally assigned by hosts within the link (e.g., using manual
configuration). Individual subnets with a prefix length longer configuration). Individual subnets with a prefix length longer than
than 24 do not receive any multicast address space from this 24 do not receive any multicast address space from this mechanism; in
mechanism; in such cases, MADCAP may be used. such cases, another mechanism must be used.
Compared to GLOP, an AS will receive more address space via this Compared to GLOP, an AS will receive more address space via this
mechanism if it has more than a /16 for unicast space. An AS will mechanism if it has more than a /16 for unicast space. An AS will
receive less address space than it does from GLOP if it has less receive less address space than it does from GLOP if it has less than
than a /16. a /16.
The owner of a UBM address can be determined by taking the The owner of a UBM address can be determined by taking the multicast
multicast address, shifting it left by 8 bits, and identifying the address, shifting it left by 8 bits, and identifying the owner of the
owner of the address space covering the resulting unicast address. address space covering the resulting unicast address.
3. Security Considerations 3. Security Considerations
The same well known intra-domain security techniques can be The same well known intra-domain security techniques can be applied
applied as with GLOP. Furthermore, when dynamic allocation is as with GLOP. Furthermore, when dynamic allocation is used within a
used within a prefix, the approach described here may have the prefix, the approach described here may have the effect of reduced
effect of reduced exposure to denial of space attacks, since the exposure to denial of space attacks, since the topological area
topological area within which nodes compete for addresses within within which nodes compete for addresses within the same prefix is
the same prefix is reduced from an entire AS to only within an reduced from an entire AS to only within an individual subnet.
individual subnet.
4. IANA Considerations 4. IANA Considerations
IANA should assign a /8 in the IPv4 multicast address space for IANA should assign a /8 in the IPv4 multicast address space for this
this purpose. purpose.
This assignment should timeout one year after the assignment is This assignment should timeout one year after the assignment is made.
made. The assignment may be renewed at that time. The assignment may be renewed at that time.
5. Author's Address 5. Informative References
[AS4B] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", February 2007, <http://www.ietf.org/
internet-drafts/draft-ietf-idr-as4bytes-13.txt>.
[RFC2730] Hanna, S., Patel, B., and M. Shah, "Multicast Address
Dynamic Client Allocation Protocol (MADCAP)", RFC 2730,
December 1999.
[RFC3180] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8",
BCP 53, RFC 3180, September 2001.
[RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", RFC 3306, August 2002.
Author's Address
Dave Thaler Dave Thaler
Microsoft Corporation Microsoft Corporation
One Microsoft Way One Microsoft Way
Redmond, WA 98052-6399 Redmond, WA 98052
Phone: +1 425 703 8835 USA
EMail: dthaler@microsoft.com
6. Informative References
[AS4B]
Vohra, Q. and E. Chen, "BGP support for four-octet AS number
space", draft-ietf-idr-as4bytes-08.txt, Work in progress,
March 2004.
[GLOP] Phone: +1 425 703 8835
Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", RFC Email: dthaler@microsoft.com
3180, September 2001.
[MADCAP] Full Copyright Statement
Hanna, S, Patel, B. and M. Shah, "Multicast Address Dynamic
Client Allocation Protocol (MADCAP)", RFC 2730, December
1999.
[V6UPBM] Copyright (C) The IETF Trust (2007).
Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", RFC 3306, August 2002.
7. Full Copyright Statement Copyright (C) The Internet Society This document is subject to the rights, licenses and restrictions
(2004). This document is subject to the rights, licenses and contained in BCP 78, and except as set forth therein, the authors
restrictions contained in BCP 78, and except as set forth therein, retain all their rights.
the authors retain all their rights.
This document and the information contained herein are provided on This document and the information contained herein are provided on an
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
PARTICULAR PURPOSE.
8. Intellectual Property Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed Intellectual Property Rights or other rights that might be claimed to
to pertain to the implementation or use of the technology pertain to the implementation or use of the technology described in
described in this document or the extent to which any license this document or the extent to which any license under such rights
under such rights might or might not be available; nor does it might or might not be available; nor does it represent that it has
represent that it has made any independent effort to identify any made any independent effort to identify any such rights. Information
such rights. Information on the procedures with respect to rights on the procedures with respect to rights in RFC documents can be
in RFC documents can be found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use attempt made to obtain a general license or permission for the use of
of such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository specification can be obtained from the IETF on-line IPR repository at
at http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention The IETF invites any interested party to bring to its attention any
any copyrights, patents or patent applications, or other copyrights, patents or patent applications, or other proprietary
proprietary rights that may cover technology that may be required rights that may cover technology that may be required to implement
to implement this standard. Please address the information to the this standard. Please address the information to the IETF at
IETF at ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
 End of changes. 37 change blocks. 
124 lines changed or deleted 129 lines changed or added

This html diff was produced by rfcdiff 1.33. The latest version is available from http://tools.ietf.org/tools/rfcdiff/