Bidirectional Protocol Independent Multicast (BIDIR-PIM)
RFC 5015
Document | Type |
RFC - Proposed Standard
(October 2007; Errata)
Updated by RFC 8736
Was draft-ietf-pim-bidir (pim WG)
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Authors | Tony Speakman , Lorenzo Vicisano , Mark Handley , Isidor Kouvelas | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5015 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Bill Fenner | ||
Send notices to | (None) |
Network Working Group M. Handley Request for Comments: 5015 UCL Category: Standards Track I. Kouvelas T. Speakman Cisco L. Vicisano Digital Fountain October 2007 Bidirectional Protocol Independent Multicast (BIDIR-PIM) Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This document discusses Bidirectional PIM (BIDIR-PIM), a variant of PIM Sparse-Mode that builds bidirectional shared trees connecting multicast sources and receivers. Bidirectional trees are built using a fail-safe Designated Forwarder (DF) election mechanism operating on each link of a multicast topology. With the assistance of the DF, multicast data is natively forwarded from sources to the Rendezvous- Point (RP) and hence along the shared tree to receivers without requiring source-specific state. The DF election takes place at RP discovery time and provides the route to the RP, thus eliminating the requirement for data-driven protocol events. Handley, et al. Standards Track [Page 1] RFC 5015 Bidirectional PIM October 2007 Table of Contents 1. Introduction ....................................................3 2. Terminology .....................................................4 2.1. Definitions ................................................4 2.2. Pseudocode Notation ........................................6 3. Protocol Specification ..........................................6 3.1. BIDIR-PIM Protocol State ...................................7 3.1.1. General Purpose State ...............................8 3.1.2. RPA State ...........................................8 3.1.3. Group State .........................................9 3.1.4. State Summarization Macros .........................10 3.2. PIM Neighbor Discovery ....................................11 3.3. Data Packet Forwarding Rules ..............................11 3.3.1. Upstream Forwarding at RP ..........................12 3.3.2. Source-Only Branches ...............................12 3.3.3. Directly Connected Sources .........................13 3.4. PIM Join/Prune Messages ...................................13 3.4.1. Receiving (*,G) Join/Prune Messages ................13 3.4.2. Sending Join/Prune Messages ........................16 3.5. Designated Forwarder (DF) Election ........................18 3.5.1. DF Requirements ....................................18 3.5.2. DF Election Description ............................19 3.5.2.1. Bootstrap Election ........................20 3.5.2.2. Loser Metric Changes ......................20 3.5.2.3. Winner Metric Changes .....................21 3.5.2.4. Winner Loses Path .........................22 3.5.2.5. Late Router Starting Up ...................22 3.5.2.6. Winner Dies ...............................22 3.5.3. Election Protocol Specification ....................22 3.5.3.1. Election State ............................22 3.5.3.2. Election Messages .........................23 3.5.3.3. Election Events ...........................24 3.5.3.4. Election Actions ..........................25 3.5.3.5. Election State Transitions ................26 3.5.4. Election Reliability Enhancements ..................30 3.5.5. Missing Pass .......................................30 3.5.6. Periodic Winner Announcement .......................30 3.6. Timers, Counters, and Constants ...........................31 3.7. BIDIR-PIM Packet Formats ..................................34 3.7.1. DF Election Packet Formats .........................34 3.7.2. Backoff Message ....................................36 3.7.3. Pass Message .......................................36 3.7.4. Bidirectional Capable PIM-Hello Option .............37 4. RP Discovery ...................................................37Show full document text