draft-ietf-mboned-ssm232-05.txt   draft-ietf-mboned-ssm232-06.txt 
INTERNET-DRAFT David Meyer INTERNET-DRAFT David Meyer
draft-ietf-mboned-ssm232-05.txt Rob Rockell draft-ietf-mboned-ssm232-06.txt Rob Rockell
Greg Shepherd Greg Shepherd
Category Best Current Practice Category Best Current Practice
Expires: November 2003 May 2003 Expires: March 2004 September 2003
Source-Specific Protocol Independent Multicast in 232/8 Source-Specific Protocol Independent Multicast in 232/8
<draft-ietf-mboned-ssm232-05.txt> <draft-ietf-mboned-ssm232-06.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.
skipping to change at page 1, line 33 skipping to change at page 1, line 32
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.
This document is a product of the . Comments should be addressed to The key words "MUST"", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
the authors, or the mailing list at "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
addressed to the authors, or the mailing list at
mboned@ns.uoregon.edu.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2003). 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
[SSM] destination addresses and are reserved for use by source- [SSM] destination addresses and are reserved for use by source-
specific applications and protocols [IANA]. This document defines specific 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.
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].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 4 2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 4
2.1. Preventing local sources from sending to shared tree. . . . 4 2.1. Preventing local sources from sending to shared tree. . . . 4
2.2. Preventing remote sources from being learned/joined via MSDP. 4 2.2. Preventing remote sources from being learned/joined via MSDP. 4
2.3. Preventing receivers from joining the shared tree . . . . . 5 2.3. Preventing receivers from joining the shared tree . . . . . 5
2.4. Preventing RP's as candidates for 232/8 . . . . . . . . . . 5 2.4. Preventing RP's as candidates for 232/8 . . . . . . . . . . 5
3. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 5 3. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 6
4. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 6 4. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations. . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations. . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.1. Normative References. . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References. . . . . . . . . . . . . . . . . . . . 8
7.2. Informative References. . . . . . . . . . . . . . . . . . . 7 7.2. Informative References. . . . . . . . . . . . . . . . . . . 8
8. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 7 8. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 9
9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 7 9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
Current PIM Sparse Mode (PIM-SM) [RFC2362] relies on the shared Current PIM Sparse Mode (PIM-SM) [RFC2362] 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 [SSM] applications and protocols [IANA] and SHOULD Source-Specific PIM [SSM] applications and protocols [IANA] and
support source-only trees only, precluding the requirement of an RP SHOULD support source-only trees only, precluding the requirement of
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 [SSM]. the source directly using Source-Specific PIM (also know as PIM-SSM
or simply SSM).
Operational best common practices in the 232/8 group address range Operational best common practices in the 232/8 group address range
are necessary to ensure shortest path source-only trees across are necessary to ensure shortest path source-only trees across
multiple domains in the Internet [SSM], and to prevent data from multiple domains in the Internet [SSM], and to prevent data from
sources sending to groups in the 232/8 range from arriving via shared sources sending to groups in the 232/8 range from arriving via shared
trees. This avoids unwanted data arrival, and allows several sources trees. This avoids unwanted data arrival, and allows several sources
to use the same group address without conflict at the receivers. to use the same group address without conflict at the receivers.
The operational practices SHOULD The operational practices SHOULD:
o Prevent local sources from sending to shared tree o Prevent local sources from sending to shared tree
o Prevent remote sources from being learned/joined via MSDP [MSDP]
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 [MSDP]
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
- preventing the RP from accepting registers for 232/8 groups from - preventing the RP from accepting registers for 232/8 groups from
the DR the DR
- preventing the RP from forwarding accepted data down (*,G) - preventing the RP from forwarding accepted data down (*,G)
tree for 232/8 groups tree for 232/8 groups
2.2. Preventing remote sources from being learned/joined via MSDP 2.2. Preventing remote sources from being learned/joined via MSDP
PIM-SS does not require active source announcements via MSDP. All PIM-SSM does not require active source announcements via MSDP. All
source announcements are received out of band, the the last hop source announcements are received out of band, the the last hop
router is responsible for sending (S,G) joins directly to the source. router being responsible for sending (S,G) joins directly to the
To prevent propagation of SAs in the 232/8 range, an RP SHOULD source. To prevent propagation of SAs in the 232/8 range, an RP
SHOULD
- never originate an SA for any 232/8 groups - never originate an SA for any 232/8 groups
- never accept or forward an SA for any 232/8 groups. - never accept or forward an SA for any 232/8 groups.
2.3. Preventing receivers from joining the shared tree 2.3. Preventing receivers from joining the shared tree
Local PIM domain practices need to be enforced to prevent local Local PIM domain practices need to be enforced to prevent local
receivers from joining the shared tree for 232/8 groups. This can be receivers from joining the shared tree for 232/8 groups. This can be
accomplished by accomplished by
skipping to change at page 5, line 29 skipping to change at page 5, line 29
source-specific [SSM] service model. It is therefore recommended source-specific [SSM] service model. It is therefore recommended
that ALL routers in the domain MUST reject AND never originate that ALL routers in the domain MUST reject AND never originate
(*,G) joins for 232/8 groups. (*,G) joins for 232/8 groups.
In those cases in which an ISP is offering its customers (or In those cases in which an ISP is offering its customers (or
others) the use of the ISP's RP, the ISP SHOULD NOT allow (*,G) others) the use of the ISP's RP, the ISP SHOULD NOT allow (*,G)
joins in the 232/8 range. joins in the 232/8 range.
2.4. Preventing RP's as candidates for 232/8 2.4. Preventing RP's as candidates for 232/8
Because PIM-SS does not require an RP, all RPs SHOULD NOT offer Because PIM-SSM does not require an RP, all RPs SHOULD NOT offer
themselves as candidates in the 232/8 range. This can be accomplished themselves as candidates in the 232/8 range. This can be accomplished
by by
- preventing RP/BSR from announcing in the 232/8 range - preventing RP/BSR from announcing in the 232/8 range
- preventing ALL routers from accepting RP delegations in the - preventing ALL routers from accepting RP delegations in the
232/8 range 232/8 range
- precluding RP functionality on RP for the 232/8 range - precluding RP functionality on RP for the 232/8 range
Note that in typical practice, RP's announce themselves as candidates
for the 224/4 (which obviously includes 232/8). It is still
acceptable to allow the advertisement of 224/4 (or any other superset
of 232/8); however, this approach relies on the second point, above,
namely, that routers silently just ignore the RP delegation in the
232/8 range, and prevent sending or receiving using the shared tree,
as described previously. Finally, an RP SHOULD NOT be configured as
a candidate RP for 232/8 (or more specific range).
3. Intellectual Property 3. 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 or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of standards-related documentation can be found in BCP-11 [RFC2028].
claims of rights made available for publication and any assurances of Copies of claims of rights made available for publication and any
licenses to be made available, or the result of an attempt made to assurances of licenses to be made available, or the result of an
obtain a general license or permission for the use of such attempt made to obtain a general license or permission for the use of
proprietary rights by implementors or users of this specification can such proprietary rights by implementors or users of this
be obtained from the IETF Secretariat. specification can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
4. Acknowledgments 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 5. 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
this document are not adhered to, some problems may surface. In
particular, section 2.3 describes the effects of non-compliance of
last-hop routers (or to some degree, rogue hosts sending PIM messages
themselves) on the source-specific service model; creating the (*,G)
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
source filtering.
6. IANA Considerations 6. IANA Considerations
This document creates a no new requirements on IANA namespaces This document creates no new requirements on IANA namespaces
[RFC2434]. [RFC2434].
7. References 7. References
7.1. Normative References 7.1. Normative References
[MSDP] Meyer, D. and B. Fenner (Editors), "The Multicast [MSDP] Meyer, D. and B. Fenner (Editors), "The Multicast
Source Discovery Protocol (MSDP)", Source Discovery Protocol (MSDP)",
draft-ietf-msdp-spec-20.txt. Work in Progress. draft-ietf-msdp-spec-20.txt. Work in Progress.
[SSM] Holbrook, H., and B. Cain,, "Source-Specific Multicast", [SSM] Holbrook, H., and B. Cain,, "Source-Specific
draft-ietf-ssm-arch-03.txt. Work in Progress. Multicast", draft-ietf-ssm-arch-03.txt. Work in
Progress.
[RFC2362] D. Estrin, et. al., "Protocol Independent Multicast-Sparse [RFC2119] Bradner, S., "Key words for use in RFCs to
Mode (PIM-SM): Protocol Specification", RFC 2362, June, Indicate Requirement Levels", RFC 2119, March,
1998. 1997.
[RFC2026] Bradner, S., "The Internet Standards Process --
Revision 3", RFC 2026/BCP 9, October, 1996.
[RFC2028] Hovey, R. and S. Bradner, "The Organizations
Involved in the IETF Standards Process", RFC
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
Writing an IANA Considerations Section in RFCs",
RFC 2434/BCP 26, October 1998.
7.2. Informative References 7.2. Informative References
[IANA] http://www.iana.org [IANA] http://www.iana.org
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March, 1997.
8. Author's Addresses 8. 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
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/