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'PIM-SO' on line 49 looks like a reference Summary: 9 errors (**), 0 flaws (~~), 2 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force G. Shepherd 3 INTERNET-DRAFT Cisco Systems 4 draft-shepherd-ssm232-01.txt E. Luczycki 5 Broadcast.com 6 draft-shepherd-ssm232-01.txt R. Rockell 7 Sprintlink 8 November, 2000 9 Expires April 2001 11 Source-Specific Protocol Independent Multicast in 232/8 12 Status of this Memo This document is an Internet Draft and is in 13 full conformance with all provisions of Section 10 of 14 RFC2026.Internet Drafts are working documents of the Internet 15 Engineering Task Force (IETF), its Areas, and its Working Groups. 16 Note that other groups may also distribute working documents as 17 Internet Drafts. Internet Drafts are draft documents valid for a 18 maximum of six months. Internet Drafts may be updated, replaced, 19 or obsoleted by other documents at any time. It is not 20 appropriate to use Internet Drafts as reference material or to 21 cite them other than as a "working draft" or "work in progress." 22 The list of current Internet-Drafts can be accessed at 23 http://www.ietf.org/ietf/1id-abstracts.txt. The list of 24 Internet-Draft Shadow Directories can be accessed at 25 http://www.ietf.org/shadow.html. Distribution of this document 26 is unlimited. 27 Abstract 28 IP Multicast group addresses in the 232/8 (232.0.0.0 to 29 232.255.255.255) range are designated as source-specific 30 multicast [SSM] destination addresses and are reserved for use by 31 source-specific applications and protocols [IANA-ALLOCATION]. 32 This document defines operational recommendations to ensure 33 source-specific behavior within the 232/8 range. 35 Introduction Current PIM Sparse Mode [PIM-SM] relies on the 36 shared Rendezvous Point (RP) tree to learn about active sources 37 for a group and to support group-generic (not source specific) 38 data distribution. The IP Multicast group address range 232/8 has 39 been designated for source-specific [SSM] applications and 40 protocols [IANA-ALLOCATION] and should support source-only trees 41 only, precluding the requirement of an RP and a shared tree; 42 active sources in the 232/8 range will be discovered out of band. 43 The PIM Sparse Mode [PIM-SM] Designated Routers (DR), with local 44 membership, are capable of joining the shortest path tree for the 45 source directly using Source-Specific PIM [PIM-SS]. 47 Operational best common practices in the 232/8 group address 48 range are necessary to ensure shortest path source-only trees 49 across multiple domains in the Internet [PIM-SO], and to prevent 50 data from sources sending to groups in the 232/8 range from 51 arriving via shared trees. This avoids unwanted data arrival, and 52 allows several sources to use the same group address without 53 conflict at the receivers. 55 The operational practices should 57 o Prevent local sources from sending to shared tree 59 o Prevent remote sources from being learned/joined via MSDP 61 o Prevent receivers from joining the shared tree 63 o Prevent RP's as candidates for 232/8 65 Operational practices in 232/8 Preventing local sources from 66 sending to shared tree Eliminatng the use of shared trees for 67 groups in 232/8, while mainaining coexistance with PIM-SM, 68 behavior of the RP and/or the DR needs to be modified. This can 69 be accomplished by 71 - preventing data for 232/8 groups from being sent encapsulated to the RP by the DR 72 - preventing the RP from accepting registers for 232/8 groups from the DR 73 - preventing the RP from forwarding accepted data down (*,G) tree 74 Preventing remote sources from being learned/joined via MSDP 75 PIM-SS does not require active source announcements via MSDP. All 76 source announcements are received out of band, the the last hop 77 router is responsible for sending (S,G) joins directly to the 78 source. To prevent propagation of SAs in the 232/8 range, an RP 79 should 81 - never originate an SA for any 232/8 groups 82 - never accept or forward an SA for any 232/8 groups. 83 Preventing receivers from joining the shared tree Local PIM 84 domain practices need to be enforced to prevent local receivers 85 from joining the shared tree for 232/8 groups. This can be 86 accomplished by 88 - preventing DR from sending (*,G) joins 89 - preventing RP from accepting (*,G) join 91 Within a local PIM domain, any last-hop router NOT preventing (*,G) joins MAY tringer (*,G) state toward the RP which intersects an existing (S,G) tree, allowing the receiver on the shared tree to receive the data. So if the last-hop routers are not preventing (*,G) joins, then all routers in the domain must also prevent (*,G) joins. 92 Preventing RP's as candidates for 232/8 Because PIM-SS does not 93 require an RP, all RPs SHOULD NOT offer themselves as candidates 94 in the 232/8 range. This can be accomplished by 96 - preventing RP/BSR from announcing in the 232/8 range 97 - preventing DRs from accepting deligations in this range 98 - precluding RP functionality on RP for the 232/8 range 100 References Internet Assigned Numbers Authority, 101 http://www.isi.edu/in-notes/iana/assignments/multicast-addresses. 102 Holbrook, H., Cain, B., "Source-Specific Multicast for IP (SSM)", 103 draft-holbrook-ssm-00.txt, September, 2000. D. Estrin, et. al., 104 "Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol 105 Specification", RFC 2362, June, 1998 Bhaskar, N., "Source- 106 Specific Protocol Independent Multicast (PIM-SS)", draft- 107 bhaskar-pim-ss-00.txt, March, 2000. Diot, C., Giuliano, L., 108 Rockell, R., "Deployment of PIM-SO at Sprint (PIM-SO)", draft- 109 bhattach-diot-PIMSO-00.txt, March, 2000. Farinacci, D., et. al. 110 "Multicast Source Discovery Protocol (MSDP)", draft-ietf-msdp- 111 spec-05.txt, February, 2000. Author's Addresses Greg Shepherd 112 Cisco Systems 170 Tasman Drive San Jose, CA, 95134 Phone: +1 541 113 912 9758 Email: shep@cisco.com 115 Ed Luczycki Broadcast.com eds@yahoo-inc.com 117 Robert Rockell Sprint Internet Service Center Reston, Virginia 118 rrockell@sprintlink.net