draft-ietf-mboned-ssm232-07.txt   draft-ietf-mboned-ssm232-08.txt 
INTERNET-DRAFT David Meyer INTERNET-DRAFT David Meyer
draft-ietf-mboned-ssm232-07.txt Rob Rockell draft-ietf-mboned-ssm232-08.txt Rob Rockell
Greg Shepherd Greg Shepherd
Category Best Current Practice Category Best Current Practice
Expires: July 2004 January 2004 Expires: September 2004 March 2004
Source-Specific Protocol Independent Multicast in 232/8 Source-Specific Protocol Independent Multicast in 232/8
<draft-ietf-mboned-ssm232-07.txt> <draft-ietf-mboned-ssm232-08.txt>
Status of this Document Status of this Document
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
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.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work 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.
The key words "MUST"", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC 2119].
This document is a product of the MBONED WG. Comments should be This document is a product of the MBONED WG. Comments should be
addressed to the authors, or the mailing list at addressed to the authors, or the mailing list at
mboned@ns.uoregon.edu. mboned@ns.uoregon.edu.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract Abstract
IP Multicast group addresses in the 232/8 (232.0.0.0 to IP Multicast group addresses in the 232/8 (232.0.0.0 to
232.255.255.255) range are designated as source-specific multicast 232.255.255.255) range are designated as source-specific multicast
destination addresses and are reserved for use by source-specific destination addresses and are reserved for use by source-specific
multicast applications and protocols. This document defines multicast applications and protocols. This document defines
operational recommendations to ensure source-specific behavior within operational recommendations to ensure source-specific behavior within
the 232/8 range. the 232/8 range.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 4 1.1. BCP, Experimental Protocols and Normative References. . . . 4
2.1. Preventing local sources from sending to shared tree. . . . 4 2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 5
2.2. Preventing remote sources from being learned/joined via MSDP. 4 2.1. Preventing local sources from sending to shared tree. . . . 5
2.3. Preventing receivers from joining the shared tree . . . . . 5 2.2. Preventing remote sources from being learned/joined via MSDP. 6
2.4. Preventing RP's as candidates for 232/8 . . . . . . . . . . 5 2.3. Preventing receivers from joining the shared tree . . . . . 6
3. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 6 2.4. Preventing RP's as candidates for 232/8 . . . . . . . . . . 7
4. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 6 3. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations. . . . . . . . . . . . . . . . . . . . 6 4. Security Considerations. . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References. . . . . . . . . . . . . . . . . . . . 8 6.1. Normative References. . . . . . . . . . . . . . . . . . . . 9
7.2. Informative References. . . . . . . . . . . . . . . . . . . 8 6.2. Informative References. . . . . . . . . . . . . . . . . . . 9
8. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 9 7. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 10
9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 9 8. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 10
9. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 11
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
Current PIM Sparse Mode (PIM-SM) [RFC2362] relies on the shared Current PIM Sparse Mode (PIM-SM) [PIM-SM] relies on the shared
Rendezvous Point (RP) tree to learn about active sources for a group Rendezvous Point (RP) tree to learn about active sources for a group
and to support group-generic (not source specific) data distribution. and to support group-generic (not source specific) data distribution.
The IP Multicast group address range 232/8 has been designated for The IP Multicast group address range 232/8 has been designated for
Source-Specific PIM [RFC3569] applications and protocols [IANA] and Source-Specific PIM [RFC3569] applications and protocols [IANA] and
SHOULD support source-only trees only, precluding the requirement of SHOULD support source-only trees only, precluding the requirement of
an RP and a shared tree; active sources in the 232/8 range will be an RP and a shared tree; active sources in the 232/8 range will be
discovered out of band. PIM Sparse Mode Designated Routers (DR), with discovered out of band. PIM Sparse Mode Designated Routers (DR), with
local membership, are capable of joining the shortest path tree for local membership, are capable of joining the shortest path tree for
the source directly using Source-Specific PIM (also known as PIM-SSM the source directly using Source-Specific PIM (also known as PIM-SSM
or simply SSM). or simply SSM).
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o Prevent local sources from sending to shared tree o Prevent local sources from sending to shared tree
o Prevent receivers from joining the shared tree o Prevent receivers from joining the shared tree
o Prevent RP's as candidates for 232/8 o Prevent RP's as candidates for 232/8
o Prevent remote sources from being learned/joined via MSDP o Prevent remote sources from being learned/joined via MSDP
[RFC3618] [RFC3618]
1.1. BCP, Experimental Protocols and Normative References
This document describes the best current practice for a widely
deployed Experimental protocol, MSDP. There is no plan to advance the
MSDP's status (for example, to Proposed Standard). The reasons for
this include:
o MSDP was originally envisioned as a temporary protocol to be
supplanted by whatever the IDMR working group produced as an
inter-domain protocol. However, the IDMR WG (or subsequently,
the BGMP WG) never produced a protocol that could be deployed
to replace MSDP.
o One of the primary reasons given for MSDP to be classified as
Experimental was that the MSDP Working Group came up with
modifications to the protocol that the WG thought made it
better but that implementors didn't see any reasons to
deploy. Without these modifications (e.g., UDP or GRE
encapsulation), MSDP can have negative consequences to initial
packets in datagram streams.
o Scalability: Although we don't know what the hard limits might
be, readvertising everything you know every 60 seconds clearly
limits the amount of state you can advertise.
o MSDP reached near ubiquitous deployment as the de-facto
standard inter-domain multicast protocol in the IPv4 Internet.
o No consensus could be reached regarding the reworking of MSDP
to address the many concerns of various constituencies within
the IETF. As a result, a decision was taken to document what is
(ubiquitously) deployed and move that document to Experimental.
While advancement of MSDP to Proposed Standard was considered,
for the reasons mentioned above, it was immediately discarded.
o The advent of protocols such as source specific multicast and
bi-directional PIM, as well as embedded RP techniques for
IPv6, have further reduced consensus that a replacement
protocol for MSDP for the IPv4 Internet is required.
The RFC Editor's policy regarding references is that they be split
into two categories known as "normative" and "informative". Normative
references specify those documents which must be read to understand
or implement the technology in an RFC (or whose technology must be
present for the technology in the new RFC to work) [RFCED]. In order
to understand this document, one must also understand both the PIM
and MSDP documents. As a result, references to these documents are
normative.
The IETF has adopted the policy that BCPs must not have normative
references to Experimental protocols. However, this document is a
special case in that the underlying Experimental document (MSDP) is
not planned to be advanced to Proposed Standard.
The MBONED Working Group requests approval under the Variance
Procedure as documented in RFC 2026 [RFC2026].
Note to RFC-Editor: If IETF/IESG approves this, please change the
above sentence into: The MBONED Working Group has requested approval
under the Variance Procedure as documented in RFC 2026 [RFC2026].
The IESG followed the Variance Procedure, and after an additional 4
week IETF Last Call evaluated the comments and status and has
approved this document.
The key words "MUST"", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC 2119].
2. Operational practices in 232/8 2. Operational practices in 232/8
2.1. Preventing local sources from sending to shared tree 2.1. Preventing local sources from sending to shared tree
Eliminating the use of shared trees for groups in 232/8, while Eliminating the use of shared trees for groups in 232/8, while
maintaining coexistence with PIM-SM, behavior of the RP and/or the DR maintaining coexistence with PIM-SM, behavior of the RP and/or the DR
needs to be modified. This can be accomplished by needs to be modified. This can be accomplished by
- preventing data for 232/8 groups from being sent encapsulated to - preventing data for 232/8 groups from being sent encapsulated to
the RP by the DR the RP by the DR
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Note that in typical practice, RP's announce themselves as candidates Note that in typical practice, RP's announce themselves as candidates
for the 224/4 (which obviously includes 232/8). It is still for the 224/4 (which obviously includes 232/8). It is still
acceptable to allow the advertisement of 224/4 (or any other superset acceptable to allow the advertisement of 224/4 (or any other superset
of 232/8); however, this approach relies on the second point, above, of 232/8); however, this approach relies on the second point, above,
namely, that routers silently just ignore the RP delegation in the namely, that routers silently just ignore the RP delegation in the
232/8 range, and prevent sending or receiving using the shared tree, 232/8 range, and prevent sending or receiving using the shared tree,
as described previously. Finally, an RP SHOULD NOT be configured as as described previously. Finally, an RP SHOULD NOT be configured as
a candidate RP for 232/8 (or more specific range). a candidate RP for 232/8 (or more specific range).
3. Intellectual Property 3. Acknowledgments
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11 [RFC2028].
Copies of claims of rights made available for publication and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementors or users of this
specification can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
4. Acknowledgments
This document is the work of many people in the multicast community, This document is the work of many people in the multicast community,
including (but not limited to) Dino Farinacci, John Meylor, John including (but not limited to) Dino Farinacci, John Meylor, John
Zwiebel, Tom Pusateri, Dave Thaler, Toerless Eckert, Leonard Zwiebel, Tom Pusateri, Dave Thaler, Toerless Eckert, Leonard
Giuliano, Mike McBride, and Pekka Savola. Giuliano, Mike McBride, and Pekka Savola.
5. Security Considerations 4. Security Considerations
This document describes operational practices that introduce no new This document describes operational practices that introduce no new
security issues to either PIM-SM or PIM-SSM. security issues to either PIM-SM or PIM-SSM.
However, in the event that the operational practices described in However, in the event that the operational practices described in
this document are not adhered to, some problems may surface. In this document are not adhered to, some problems may surface. In
particular, section 2.3 describes the effects of non-compliance of particular, section 2.3 describes the effects of non-compliance of
last-hop routers (or to some degree, rogue hosts sending PIM messages last-hop routers (or to some degree, rogue hosts sending PIM messages
themselves) on the source-specific service model; creating the (*,G) themselves) on the source-specific service model; creating the (*,G)
state for source-specific (S,G) could enable a receiver to receive state for source-specific (S,G) could enable a receiver to receive
data it should not get. This can be mitigated by host-side multicast data it should not get. This can be mitigated by host-side multicast
source filtering. source filtering.
6. IANA Considerations 5. IANA Considerations
This document creates no new requirements on IANA namespaces This document creates no new requirements on IANA namespaces
[RFC2434]. [RFC2434].
7. References 6. References
7.1. Normative References 6.1. Normative References
[PIM-SM] Fenner, B., et. al, "Protocol Independent Multicast -
Sparse Mode (PIM-SM): Protocol Specification
(Revised)", draft-ietf-pim-sm-v2-new-09.txt. Work
in progress.
[RFC2119] Bradner, S., "Key words for use in RFCs to [RFC2119] Bradner, S., "Key words for use in RFCs to
Indicate Requirement Levels", RFC 2119, March, Indicate Requirement Levels", RFC 2119, March,
1997. 1997.
[RFC2026] Bradner, S., "The Internet Standards Process -- [RFC2026] Bradner, S., "The Internet Standards Process --
Revision 3", RFC 2026/BCP 9, October, 1996. Revision 3", RFC 2026/BCP 9, October, 1996.
[RFC2028] Hovey, R. and S. Bradner, "The Organizations [RFC2028] Hovey, R. and S. Bradner, "The Organizations
Involved in the IETF Standards Process", RFC Involved in the IETF Standards Process", RFC
2028/BCP 11, October, 1996. 2028/BCP 11, October, 1996.
[RFC2362] Estrin, D., et. al., "Protocol Independent
Multicast-Sparse Mode (PIM-SM): Protocol
Specification", RFC 2362, June, 1998.
[RFC2434] Narten, T., and H. Alvestrand, "Guidelines for [RFC2434] Narten, T., and H. Alvestrand, "Guidelines for
Writing an IANA Considerations Section in RFCs", Writing an IANA Considerations Section in RFCs",
RFC 2434/BCP 26, October 1998. RFC 2434/BCP 26, October 1998.
[RFC3569] Bhattacharyya, S. Editor, "An Overview of [RFC3569] Bhattacharyya, S. Editor, "An Overview of
Source-Specific Multicast (SSM)" RFC 3569, July, Source-Specific Multicast (SSM)" RFC 3569, July,
2003. 2003.
[RFC3618] Meyer, D. and B. Fenner (Editors), "The Multicast [RFC3618] Meyer, D. and B. Fenner (Editors), "The Multicast
Source Discovery Protocol (MSDP)", RFC 3618, Source Discovery Protocol (MSDP)", RFC 3618,
October, 2003. October, 2003.
7.2. Informative References 6.2. Informative References
[IANA] http://www.iana.org [IANA] http://www.iana.org
8. Author's Addresses 7. Author's Addresses
David Meyer David Meyer
Email: dmm@1-4-5.net Email: dmm@1-4-5.net
Robert Rockell Robert Rockell
Sprint Sprint
Email: rrockell@sprint.net Email: rrockell@sprint.net
Greg Shepherd Greg Shepherd
Procket Procket
Email: shep@procket.com Email: shep@procket.com
9. Full Copyright Statement 8. Full Copyright Statement
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78 and
except as set forth therein, the authors retain all their rights.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
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The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns. revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
9. Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
10. Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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