draft-ietf-mboned-ssm232-08.txt   draft-ietf-mboned-ssm232-09.txt 
INTERNET-DRAFT David Meyer Network Working Group Shepherd
draft-ietf-mboned-ssm232-08.txt Rob Rockell Internet-Draft Cisco
Greg Shepherd Expires: December 16, 2006 Rockell
Category Best Current Practice Sprint
Meyer
Cisco
June 14, 2006
Source-Specific Protocol Independent Multicast in 232/8 Source-Specific Protocol Independent Multicast in 232/8
<draft-ietf-mboned-ssm232-08.txt> draft-ietf-mboned-ssm232-09
Status of this Document Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2006).
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.
Requirements Language
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 [RFC2119].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. BCP, Experimental Protocols and Normative References. . . . 4 1.1. BCP, Experimental Protocols and Normative References . . . 3
2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 5 2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 4
2.1. Preventing local sources from sending to shared tree. . . . 5 2.1. Preventing local sources from sending to shared tree . . . 4
2.2. Preventing remote sources from being learned/joined via MSDP. 6 2.2. Preventing remote sources from being learned/joined
2.3. Preventing receivers from joining the shared tree . . . . . 6 via MSDP . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4. Preventing RP's as candidates for 232/8 . . . . . . . . . . 7 2.3. Preventing receivers from joining the shared tree . . . . . 5
3. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 7 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations. . . . . . . . . . . . . . . . . . . . 7 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 8 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References. . . . . . . . . . . . . . . . . . . . 9 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7
6.2. Informative References. . . . . . . . . . . . . . . . . . . 9 6.2. Informative References . . . . . . . . . . . . . . . . . . 7
7. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 10 7. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 10 8. Intellectual Property and Copyright Statements . . . . . . . . . . 9
9. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 11
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
Current PIM Sparse Mode (PIM-SM) [PIM-SM] relies on the shared Current PIM Sparse Mode (PIM-SM) [I-D.pim-sm-v2-new] relies on the
Rendezvous Point (RP) tree to learn about active sources for a group shared Rendezvous Point (RP) tree to learn about active sources for a
and to support group-generic (not source specific) data distribution. group and to support group-generic (Any Source Multicast or ASM) data
The IP Multicast group address range 232/8 has been designated for distribution. The IP Multicast group address range 232/8 has been
Source-Specific PIM [RFC3569] applications and protocols [IANA] and designated for Source-Specific Multicast (SSM) applications and
SHOULD support source-only trees only, precluding the requirement of protocols [IANA] and SHOULD support source-only trees only,
an RP and a shared tree; active sources in the 232/8 range will be precluding the requirement of an RP and a shared tree; active sources
discovered out of band. PIM Sparse Mode Designated Routers (DR), with in the 232/8 range will be discovered out of band. PIM-SM Designated
local membership, are capable of joining the shortest path tree for Routers (DR), with local membership, are capable of joining the
the source directly using Source-Specific PIM (also known as PIM-SSM shortest path tree for the source directly using SSM functionality of
or simply SSM). PIM-SM.
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 [RFC3569], and to prevent data from multiple domains in the Internet [RFC3569], 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 receivers from joining the shared
o Prevent local sources from sending to shared tree tree o Prevent RP's as candidates for 232/8 o Prevent remote sources
from being learned/joined via MSDP [RFC3618]
o Prevent receivers from joining the shared tree
o Prevent RP's as candidates for 232/8
o Prevent remote sources from being learned/joined via MSDP
[RFC3618]
1.1. BCP, Experimental Protocols and Normative References 1.1. BCP, Experimental Protocols and Normative References
This document describes the best current practice for a widely This document describes the best current practice for a widely
deployed Experimental protocol, MSDP. There is no plan to advance the deployed Experimental protocol, MSDP. There is no plan to advance
MSDP's status (for example, to Proposed Standard). The reasons for the MSDP's status (for example, to Proposed Standard). The reasons
this include: for this include:
o MSDP was originally envisioned as a temporary protocol to be o MSDP was originally envisioned as a temporary protocol to be
supplanted by whatever the IDMR working group produced as an supplanted by whatever the IDMR working group produced as an
inter-domain protocol. However, the IDMR WG (or subsequently, inter-domain protocol. However, the IDMR WG (or subsequently, the
the BGMP WG) never produced a protocol that could be deployed BGMP WG) never produced a protocol that could be deployed to
to replace MSDP. replace MSDP.
o One of the primary reasons given for MSDP to be classified as o One of the primary reasons given for MSDP to be classified as
Experimental was that the MSDP Working Group came up with Experimental was that the MSDP Working Group came up with
modifications to the protocol that the WG thought made it modifications to the protocol that the WG thought made it better
better but that implementors didn't see any reasons to but that implementors didn't see any reasons to deploy. Without
deploy. Without these modifications (e.g., UDP or GRE these modifications (e.g., UDP or GRE encapsulation), MSDP can
encapsulation), MSDP can have negative consequences to initial have negative consequences to initial packets in datagram streams.
packets in datagram streams.
o Scalability: Although we don't know what the hard limits might o Scalability: Although we don't know what the hard limits might be,
be, readvertising everything you know every 60 seconds clearly readvertising everything you know every 60 seconds clearly limits
limits the amount of state you can advertise. the amount of state you can advertise.
o MSDP reached near ubiquitous deployment as the de-facto o MSDP reached near ubiquitous deployment as the de-facto standard
standard inter-domain multicast protocol in the IPv4 Internet. inter-domain multicast protocol in the IPv4 Internet.
o No consensus could be reached regarding the reworking of MSDP o No consensus could be reached regarding the reworking of MSDP to
to address the many concerns of various constituencies within address the many concerns of various constituencies within the
the IETF. As a result, a decision was taken to document what is IETF. As a result, a decision was taken to document what is
(ubiquitously) deployed and move that document to Experimental. (ubiquitously) deployed and move that document to Experimental.
While advancement of MSDP to Proposed Standard was considered, While advancement of MSDP to Proposed Standard was considered, for
for the reasons mentioned above, it was immediately discarded. the reasons mentioned above, it was immediately discarded.
o The advent of protocols such as source specific multicast and o The advent of source specific multicast and protocols such as bi-
bi-directional PIM, as well as embedded RP techniques for directional PIM, as well as embedded RP techniques for IPv6, have
IPv6, have further reduced consensus that a replacement further reduced consensus that a replacement protocol for MSDP for
protocol for MSDP for the IPv4 Internet is required. the IPv4 Internet is required.
The RFC Editor's policy regarding references is that they be split The RFC Editor's policy regarding references is that they be split
into two categories known as "normative" and "informative". Normative into two categories known as "normative" and "informative".
references specify those documents which must be read to understand Normative references specify those documents which must be read to
or implement the technology in an RFC (or whose technology must be understand or implement the technology in an RFC (or whose technology
present for the technology in the new RFC to work) [RFCED]. In order must be present for the technology in the new RFC to work) [RFCED].
to understand this document, one must also understand both the PIM In order to understand this document, one must also understand both
and MSDP documents. As a result, references to these documents are the PIM-SM and MSDP documents. As a result, references to these
normative. documents are normative. The IETF has adopted the policy that BCPs
must not have normative references to Experimental protocols.
The IETF has adopted the policy that BCPs must not have normative However, this document is a special case in that the underlying
references to Experimental protocols. However, this document is a Experimental document (MSDP) is not planned to be advanced to
special case in that the underlying Experimental document (MSDP) is Proposed Standard. The MBONED Working Group requests approval under
not planned to be advanced to Proposed Standard. the Variance Procedure as documented in RFC 2026 [RFC2026]. Note to
RFC-Editor: If IETF/IESG approves this, please change the above
The MBONED Working Group requests approval under the Variance sentence into: The MBONED Working Group has requested approval under
Procedure as documented in RFC 2026 [RFC2026]. the Variance Procedure as documented in RFC 2026 [RFC2026]. The IESG
followed the Variance Procedure, and after an additional 4 week IETF
Note to RFC-Editor: If IETF/IESG approves this, please change the Last Call evaluated the comments and status and has approved this
above sentence into: The MBONED Working Group has requested approval document.
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 ASM in PIM-SM, behavior of the RP and/or
needs to be modified. This can be accomplished by the DR needs to be modified. This can be accomplished by
o 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 o preventing the RP from accepting registers for 232/8 groups from
the DR the DR.
- preventing the RP from forwarding accepted data down (*,G) o preventing the RP from forwarding accepted data down (*,G) tree
tree for 232/8 groups 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-SSM does not require active source announcements via MSDP. All 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 being responsible for sending (S,G) joins directly to the router being responsible for sending (S,G) joins directly to the
source. To prevent propagation of SAs in the 232/8 range, an RP source. To prevent propagation of SAs in the 232/8 range, an RP
SHOULD SHOULD
- never originate an SA for any 232/8 groups o never originate an SA for any 232/8 groups.
- never accept or forward an SA for any 232/8 groups. o 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-SM 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 232/8 range.
- preventing DR from sending (*,G) joins for 232/8 groups o preventing DR from sending (*,G) joins for 232/8 groups.
- preventing RP from accepting (*,G) join for 232/8 groups o preventing RP from accepting (*,G) join for 232/8 groups.
However, within a local PIM domain, any last-hop router NOT However, within a local PIM-SM domain, any last-hop router NOT
preventing (*,G) joins may trigger unwanted (*,G) state toward the RP preventing (*,G) joins may trigger unwanted (*,G) state toward the RP
which intersects an existing (S,G) tree, allowing the receiver on the which intersects an existing (S,G) tree, allowing the receiver on the
shared tree to receive the data, breaking the source-specific shared tree to receive the data, breaking the source-specific
[RFC3569] service model. It is therefore recommended that ALL routers [RFC3569] service model. It is therefore recommended that ALL
in the domain MUST reject AND never originate (*,G) joins for 232/8 routers in the domain MUST reject AND never originate (*,G) joins for
groups. 232/8 groups. In those cases in which an ISP is offering its
customers (or others) the use of the ISP's RP, the ISP SHOULD NOT
In those cases in which an ISP is offering its customers (or others) allow (*,G) joins in the 232/8 range.
the use of the ISP's RP, the ISP SHOULD NOT allow (*,G) joins in the
232/8 range.
2.4. Preventing RP's as candidates for 232/8
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
by
- preventing RP/BSR from announcing in the 232/8 range Because SSM does not require a PIM-SM RP, all RPs SHOULD NOT offer
themselves as candidates in the 232/8 range. This can be
accomplished by
- preventing ALL routers from accepting RP delegations in the o preventing RP/BSR from announcing in the 232/8 range
232/8 range o preventing ALL routers from accepting RP delegations in the 232/8
range
- precluding RP functionality on RP for the 232/8 range o precluding RP functionality on RP for the 232/8 range
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. Acknowledgments 3. IANA Considerations
This document is the work of many people in the multicast community, This document creates no new requirements on IANA namespaces
including (but not limited to) Dino Farinacci, John Meylor, John [RFC2434].
Zwiebel, Tom Pusateri, Dave Thaler, Toerless Eckert, Leonard
Giuliano, Mike McBride, and Pekka Savola.
4. 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 PIM-SM in either SSM or ASM operation. However,
in the event that the operational practices described in this
However, in the event that the operational practices described in 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-SM
themselves) on the source-specific service model; creating the (*,G) messages themselves) on the source-specific service model; creating
state for source-specific (S,G) could enable a receiver to receive the (*,G) state for source-specific (S,G) could enable a receiver to
data it should not get. This can be mitigated by host-side multicast receive data it should not get. This can be mitigated by host-side
source filtering. multicast source filtering.
5. IANA Considerations 5. Acknowledgements
This document creates no new requirements on IANA namespaces This document is the work of many people in the multicast community,
[RFC2434]. including (but not limited to) Dino Farinacci, John Meylor, John
Zwiebel, Tom Pusateri, Dave Thaler, Toerless Eckert, Leonard
Giuliano, Mike McBride, and Pekka Savola.
6. References 6. References
6.1. Normative References 6.1. Normative References
[PIM-SM] Fenner, B., et. al, "Protocol Independent Multicast - [I-D.ietf-pim-sm-v2-new]
Sparse Mode (PIM-SM): Protocol Specification Fenner, B., "Protocol Independent Multicast - Sparse Mode
(Revised)", draft-ietf-pim-sm-v2-new-09.txt. Work (PIM-SM): Protocol Specification (Revised)",
in progress. draft-ietf-pim-sm-v2-new-12 (work in progress),
March 2006.
[RFC2119] Bradner, S., "Key words for use in RFCs to [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
Indicate Requirement Levels", RFC 2119, March, 3", BCP 9, RFC 2026, October 1996.
1997.
[RFC2026] Bradner, S., "The Internet Standards Process -- [RFC2028] Hovey, R. and S. Bradner, "The Organizations Involved in
Revision 3", RFC 2026/BCP 9, October, 1996. the IETF Standards Process", BCP 11, RFC 2028,
October 1996.
[RFC2028] Hovey, R. and S. Bradner, "The Organizations [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Involved in the IETF Standards Process", RFC Requirement Levels", BCP 14, RFC 2119, March 1997.
2028/BCP 11, October, 1996.
[RFC2434] Narten, T., and H. Alvestrand, "Guidelines for [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
Writing an IANA Considerations Section in RFCs", IANA Considerations Section in RFCs", BCP 26, RFC 2434,
RFC 2434/BCP 26, October 1998. October 1998.
[RFC3569] Bhattacharyya, S. Editor, "An Overview of [RFC3569] Bhattacharyya, S., "An Overview of Source-Specific
Source-Specific Multicast (SSM)" RFC 3569, July, Multicast (SSM)", RFC 3569, July 2003.
2003.
[RFC3618] Meyer, D. and B. Fenner (Editors), "The Multicast [RFC3618] Fenner, B. and D. Meyer, "Multicast Source Discovery
Source Discovery Protocol (MSDP)", RFC 3618, Protocol (MSDP)", RFC 3618, October 2003.
October, 2003.
6.2. Informative References 6.2. Informative References
[IANA] http://www.iana.org [IANA] "http://www.iana.org", 2005.
7. Author's Addresses
David Meyer
Email: dmm@1-4-5.net
Robert Rockell 7. Authors' Addresses
Sprint
Email: rrockell@sprint.net
Greg Shepherd Greg Shepherd
Procket Cisco
Email: shep@procket.com
8. Full Copyright Statement Email: shep@cisco.com
Copyright (C) The Internet Society (2004). This document is subject Robert Rockell
to the rights, licenses and restrictions contained in BCP 78 and Sprint
except as set forth therein, the authors retain all their rights.
This document and translations of it may be copied and furnished to Email: rrockell@sprint.net
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be Dave Meyer
revoked by the Internet Society or its successors or assigns. Cisco
This document and the information contained herein is provided on an Email: dmm@1-4-5.net
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
9. Intellectual Property 8. Intellectual Property Statement
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 to Intellectual Property Rights 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; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights 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 of attempt made to obtain a general license or permission for the use 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 at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
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 that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf- this standard. Please address the information to the IETF at
ipr@ietf.org. ietf-ipr@ietf.org.
10. Acknowledgement Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2006). 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.
Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
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