--- 1/draft-ietf-mboned-ssm232-08.txt 2006-07-17 22:12:45.000000000 +0200 +++ 2/draft-ietf-mboned-ssm232-09.txt 2006-07-17 22:12:45.000000000 +0200 @@ -1,372 +1,346 @@ -INTERNET-DRAFT David Meyer -draft-ietf-mboned-ssm232-08.txt Rob Rockell - Greg Shepherd -Category Best Current Practice +Network Working Group Shepherd +Internet-Draft Cisco +Expires: December 16, 2006 Rockell + Sprint + Meyer + Cisco + June 14, 2006 + Source-Specific Protocol Independent Multicast in 232/8 - + draft-ietf-mboned-ssm232-09 -Status of this Document +Status of this Memo - This document is an Internet-Draft and is in full conformance with - all provisions of Section 10 of RFC2026. + By submitting this Internet-Draft, each author represents that any + applicable patent or other IPR claims of which he or she is aware + have been or will be disclosed, and any of which he or she becomes + aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." 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 http://www.ietf.org/shadow.html. - 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. + This Internet-Draft will expire on December 16, 2006. Copyright Notice - Copyright (C) The Internet Society (2004). All Rights Reserved. + Copyright (C) The Internet Society (2006). Abstract IP Multicast group addresses in the 232/8 (232.0.0.0 to 232.255.255.255) range are designated as source-specific multicast destination addresses and are reserved for use by source-specific multicast applications and protocols. This document defines operational recommendations to ensure source-specific behavior within 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 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1.1. BCP, Experimental Protocols and Normative References. . . . 4 - 2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 5 - 2.1. Preventing local sources from sending to shared tree. . . . 5 - 2.2. Preventing remote sources from being learned/joined via MSDP. 6 - 2.3. Preventing receivers from joining the shared tree . . . . . 6 - 2.4. Preventing RP's as candidates for 232/8 . . . . . . . . . . 7 - 3. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 7 - 4. Security Considerations. . . . . . . . . . . . . . . . . . . . 7 - 5. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 8 - 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 6.1. Normative References. . . . . . . . . . . . . . . . . . . . 9 - 6.2. Informative References. . . . . . . . . . . . . . . . . . . 9 - 7. Author's Addresses . . . . . . . . . . . . . . . . . . . . . . 10 - 8. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 10 - 9. Intellectual Property. . . . . . . . . . . . . . . . . . . . . 11 - 10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 11 + 1.1. BCP, Experimental Protocols and Normative References . . . 3 + 2. Operational practices in 232/8 . . . . . . . . . . . . . . . . 4 + 2.1. Preventing local sources from sending to shared tree . . . 4 + 2.2. Preventing remote sources from being learned/joined + via MSDP . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 2.3. Preventing receivers from joining the shared tree . . . . . 5 + 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 + 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 + 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 + 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 + 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 + 6.2. Informative References . . . . . . . . . . . . . . . . . . 7 + 7. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 + 8. Intellectual Property and Copyright Statements . . . . . . . . . . 9 1. Introduction - Current PIM Sparse Mode (PIM-SM) [PIM-SM] relies on the shared - Rendezvous Point (RP) tree to learn about active sources for a group - and to support group-generic (not source specific) data distribution. - The IP Multicast group address range 232/8 has been designated for - Source-Specific PIM [RFC3569] applications and protocols [IANA] and - 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 - discovered out of band. PIM Sparse Mode Designated Routers (DR), with - local membership, are capable of joining the shortest path tree for - the source directly using Source-Specific PIM (also known as PIM-SSM - or simply SSM). + Current PIM Sparse Mode (PIM-SM) [I-D.pim-sm-v2-new] relies on the + shared Rendezvous Point (RP) tree to learn about active sources for a + group and to support group-generic (Any Source Multicast or ASM) data + distribution. The IP Multicast group address range 232/8 has been + designated for Source-Specific Multicast (SSM) applications and + protocols [IANA] and 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 discovered out of band. PIM-SM Designated + Routers (DR), with local membership, are capable of joining the + shortest path tree for the source directly using SSM functionality of + PIM-SM. Operational best common practices in the 232/8 group address range are necessary to ensure shortest path source-only trees across multiple domains in the Internet [RFC3569], and to prevent data from sources sending to groups in the 232/8 range from arriving via shared trees. This avoids unwanted data arrival, and allows several sources to use the same group address without conflict at the receivers. - The operational practices SHOULD: - - o Prevent local sources from sending to shared tree - - 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] + The operational practices SHOULD: o Prevent local sources from + sending to shared tree 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 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: + 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. + 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. + 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 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 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 + 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. + 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. + o The advent of source specific multicast and protocols such as 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]. + 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-SM 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. 2. Operational practices in 232/8 2.1. Preventing local sources from sending to shared tree 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 - needs to be modified. This can be accomplished by - - - preventing data for 232/8 groups from being sent encapsulated to - the RP by the DR + maintaining coexistence with ASM in PIM-SM, behavior of the RP and/or + the DR needs to be modified. This can be accomplished by + o preventing data for 232/8 groups from being sent encapsulated to + the RP by the DR. - - preventing the RP from accepting registers for 232/8 groups from - the DR + o preventing the RP from accepting registers for 232/8 groups from + the DR. - - preventing the RP from forwarding accepted data down (*,G) - tree for 232/8 groups + o preventing the RP from forwarding accepted data down (*,G) tree + for 232/8 groups. 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 router being responsible for sending (S,G) joins directly to the source. To prevent propagation of SAs in the 232/8 range, an RP 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 - 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 - 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 which intersects an existing (S,G) tree, allowing the receiver on the shared tree to receive the data, breaking the source-specific - [RFC3569] service model. It is therefore recommended that ALL routers - in the domain MUST reject AND never originate (*,G) joins for 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 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 + [RFC3569] service model. It is therefore recommended that ALL + routers in the domain MUST reject AND never originate (*,G) joins for + 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 + allow (*,G) joins in the 232/8 range. - - 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 - 232/8 range + o preventing RP/BSR from announcing in the 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 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. Acknowledgments +3. IANA Considerations - This document is the work of many people in the multicast community, - including (but not limited to) Dino Farinacci, John Meylor, John - Zwiebel, Tom Pusateri, Dave Thaler, Toerless Eckert, Leonard - Giuliano, Mike McBride, and Pekka Savola. + This document creates no new requirements on IANA namespaces + [RFC2434]. 4. Security Considerations This document describes operational practices that introduce no new - 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 + security issues to PIM-SM in either SSM or ASM operation. 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. + last-hop routers (or to some degree, rogue hosts sending PIM-SM + 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. -5. IANA Considerations +5. Acknowledgements - This document creates no new requirements on IANA namespaces - [RFC2434]. + This document is the work of many people in the multicast community, + 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 6.1. 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. + [I-D.ietf-pim-sm-v2-new] + Fenner, B., "Protocol Independent Multicast - Sparse Mode + (PIM-SM): Protocol Specification (Revised)", + draft-ietf-pim-sm-v2-new-12 (work in progress), + March 2006. - [RFC2119] Bradner, S., "Key words for use in RFCs to - Indicate Requirement Levels", RFC 2119, March, - 1997. + [RFC2026] Bradner, S., "The Internet Standards Process -- Revision + 3", BCP 9, RFC 2026, October 1996. - [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", BCP 11, RFC 2028, + October 1996. - [RFC2028] Hovey, R. and S. Bradner, "The Organizations - Involved in the IETF Standards Process", RFC - 2028/BCP 11, October, 1996. + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. - [RFC2434] Narten, T., and H. Alvestrand, "Guidelines for - Writing an IANA Considerations Section in RFCs", - RFC 2434/BCP 26, October 1998. + [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an + IANA Considerations Section in RFCs", BCP 26, RFC 2434, + October 1998. - [RFC3569] Bhattacharyya, S. Editor, "An Overview of - Source-Specific Multicast (SSM)" RFC 3569, July, - 2003. + [RFC3569] Bhattacharyya, S., "An Overview of Source-Specific + Multicast (SSM)", RFC 3569, July 2003. - [RFC3618] Meyer, D. and B. Fenner (Editors), "The Multicast - Source Discovery Protocol (MSDP)", RFC 3618, - October, 2003. + [RFC3618] Fenner, B. and D. Meyer, "Multicast Source Discovery + Protocol (MSDP)", RFC 3618, October 2003. 6.2. Informative References - [IANA] http://www.iana.org - -7. Author's Addresses - - David Meyer - Email: dmm@1-4-5.net + [IANA] "http://www.iana.org", 2005. - Robert Rockell - Sprint - Email: rrockell@sprint.net +7. Authors' Addresses Greg Shepherd - Procket - Email: shep@procket.com + Cisco -8. Full Copyright Statement + Email: shep@cisco.com - 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. + Robert Rockell + Sprint - This document and translations of it may be copied and furnished to - 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. + Email: rrockell@sprint.net - The limited permissions granted above are perpetual and will not be - revoked by the Internet Society or its successors or assigns. + Dave Meyer + Cisco - This document and the information contained herein is provided on an - "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. + Email: dmm@1-4-5.net -9. Intellectual Property +8. Intellectual Property Statement 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. + this standard. Please address the information to the IETF at + 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 Internet Society.