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(See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** There are 2 instances of too long lines in the document, the longest one being 6 characters in excess of 72. ** The abstract seems to contain references ([RFC2119], [SSM], [IANA]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. ** The document seems to lack a both a reference to RFC 2119 and the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. RFC 2119 keyword, line 51: '... The keywords MUST, MUST NOT, MAY, O...' RFC 2119 keyword, line 52: '... SHALL, SHALL NOT, SHOULD, SHOULD NO...' RFC 2119 keyword, line 61: '... specific [SSM] applications and protocols [IANA] and SHOULD support...' RFC 2119 keyword, line 75: '... The operational practices SHOULD...' RFC 2119 keyword, line 105: '...f SAs in the 232/8 range, an RP SHOULD...' (2 more instances...) 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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Missing reference section? 'SSM' on line 142 looks like a reference -- Missing reference section? 'IANA' on line 140 looks like a reference -- Missing reference section? 'RFC2119' on line 145 looks like a reference -- Missing reference section? 'RFC2362' on line 148 looks like a reference -- Missing reference section? 'MSDP' on line 152 looks like a reference Summary: 10 errors (**), 0 flaws (~~), 4 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group Greg Shepherd 2 INTERNET DRAFT Juniper Networks 3 E. Luczycki 4 Yahoo! Broadcast 5 Rob Rockell 6 Sprinlink 7 Category Best Current Practices 8 April, 2001 10 Source-Specific Protocol Independent Multicast in 232/8 12 14 1. Status of this Memo 16 This document specifies an Internet Best Current Practices for the 17 Internet Community, and requests discussion and suggestions for 18 improvements. Distribution of this memo is unlimited. 20 This document is an Internet-Draft and is in full conformance with 21 all provisions of Section 10 of RFC 2026. 23 Internet Drafts are working documents of the Internet Engineering 24 Task Force (IETF), its areas, and its working groups. Note that other 25 groups may also distribute working documents as Internet-Drafts. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 The list of current Internet-Drafts can be accessed at 33 http://www.ietf.org/ietf/1id-abstracts.txt. 35 The list of Internet-Draft Shadow Directories can be accessed at 36 http://www.ietf.org/shadow.html. 38 2. Copyright Notice 40 Copyright (C) The Internet Society (2001). All Rights Reserved. 42 3. Abstract 44 IP Multicast group addresses in the 232/8 (232.0.0.0 to 45 232.255.255.255) range are designated as source-specific multicast 46 [SSM] destination addresses and are reserved for use by source- 47 specific applications and protocols [IANA]. This document defines 48 operational recommendations to ensure source-specific behavior within 49 the 232/8 range. 51 The keywords MUST, MUST NOT, MAY, OPTIONAL, REQUIRED, RECOMMENDED, 52 SHALL, SHALL NOT, SHOULD, SHOULD NOT are to be interpreted as defined 53 in RFC 2119 [RFC2119]. 55 4. Introduction 57 Current PIM Sparse Mode [RFC2362] relies on the shared Rendezvous 58 Point (RP) tree to learn about active sources for a group and to 59 support group-generic (not source specific) data distribution. The IP 60 Multicast group address range 232/8 has been designated for source- 61 specific [SSM] applications and protocols [IANA] and SHOULD support 62 source-only trees only, precluding the requirement of an RP and a 63 shared tree; active sources in the 232/8 range will be discovered out 64 of band. PIM Sparse Mode Designated Routers (DR), with local 65 membership, are capable of joining the shortest path tree for the 66 source directly using Source-Specific PIM [SSM]. 68 Operational best common practices in the 232/8 group address range 69 are necessary to ensure shortest path source-only trees across 70 multiple domains in the Internet [SSM], and to prevent data from 71 sources sending to groups in the 232/8 range from arriving via shared 72 trees. This avoids unwanted data arrival, and allows several sources 73 to use the same group address without conflict at the receivers. 75 The operational practices SHOULD 77 o Prevent local sources from sending to shared tree 79 o Prevent remote sources from being learned/joined via MSDP [MSDP] 81 o Prevent receivers from joining the shared tree 82 o Prevent RP's as candidates for 232/8 84 5. Operational practices in 232/8 86 5.1. Preventing local sources from sending to shared tree 88 Eliminating the use of shared trees for groups in 232/8, while 89 maintaining coexistence with PIM-SM, behavior of the RP and/or the DR 90 needs to be modified. This can be accomplished by 92 - preventing data for 232/8 groups from being sent encapsulated to 93 the RP by the DR 95 - preventing the RP from accepting registers for 232/8 groups from 96 the DR 98 - preventing the RP from forwarding accepted data down (*,G) tree 100 5.2. Preventing remote sources from being learned/joined via MSDP 102 PIM-SS does not require active source announcements via MSDP. All 103 source announcements are received out of band, the the last hop 104 router is responsible for sending (S,G) joins directly to the source. 105 To prevent propagation of SAs in the 232/8 range, an RP SHOULD 107 - never originate an SA for any 232/8 groups 109 - never accept or forward an SA for any 232/8 groups. 111 5.3. Preventing receivers from joining the shared tree 113 Local PIM domain practices need to be enforced to prevent local 114 receivers from joining the shared tree for 232/8 groups. This can be 115 accomplished by 117 - preventing DR from sending (*,G) joins 119 - preventing RP from accepting (*,G) join 121 Within a local PIM domain, any last-hop router NOT preventing (*,G) 122 joins MAY trigger (*,G) state toward the RP which intersects an 123 existing (S,G) tree, allowing the receiver on the shared tree to 124 receive the data. So if the last-hop routers are not preventing (*,G) 125 joins, then all routers in the domain must also prevent (*,G) joins. 127 5.4. Preventing RP's as candidates for 232/8 129 Because PIM-SS does not require an RP, all RPs SHOULD NOT offer them- 130 selves as candidates in the 232/8 range. This can be accomplished by 132 - preventing RP/BSR from announcing in the 232/8 range 134 - preventing DRs from accepting delegations in this range 136 - precluding RP functionality on RP for the 232/8 range 138 6. References 140 [IANA] http://www.iana.org 142 [SSM] Holbrook, H., Cain, B., "Source-Specific Multicast for IP 143 (SSM)", draft-holbrook-ssm-02.txt, March, 2001. 145 [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate 146 Requirement Levels", RFC 2119, March, 1997. 148 [RFC2362] D. Estrin, et. al., "Protocol Independent Multicast-Sparse 149 Mode (PIM-SM): Protocol Specification", RFC 2362, June, 150 1998. 152 [MSDP] D. Meyer, Editor, "Multicast Source Discovery Protocol 153 (MSDP)", draft-ietf-msdp-spec-07.txt, April, 2001. 155 7. Author's Addresses 157 Greg Shepherd 158 Juniper Networks 159 Email: shep@juniper.net 161 Ed Luczycki 162 Yahoo! Broadcast 163 Email: eds@yahoo-inc.com 165 Robert Rockell 166 Sprint Internet Service Center 167 Reston, Virginia 168 Email: rrockell@sprintlink.net 170 8. Full Copyright Statement 172 Copyright (C) The Internet Society (2001). All Rights Reserved. 174 This document and translations of it may be copied and furnished to 175 others, and derivative works that comment on or otherwise explain it 176 or assist in its implementation may be prepared, copied, published 177 and distributed, in whole or in part, without restriction of any 178 kind, provided that the above copyright notice and this paragraph are 179 included on all such copies and derivative works. However, this 180 document itself may not be modified in any way, such as by removing 181 the copyright notice or references to the Internet Society or other 182 Internet organizations, except as needed for the purpose of develop- 183 ing Internet standards in which case the procedures for copyrights 184 defined in the Internet Standards process must be followed, or as 185 required to translate it into languages other than English. 187 The limited permissions granted above are perpetual and will not be 188 revoked by the Internet Society or its successors or assigns. 190 This document and the information contained herein is provided on an 191 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 192 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 193 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 194 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MER- 195 CHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.