wimaxing 2008-6-24 23:25
rfc5015-Bidirectional Protocol Independent Multicast (BIDIR-PIM)
【资料成文时间】： 2007
【语言】：英文
【页数】：43
【何人（公司）所著】：
【文件格式】： PDF
【文件原名】：Bidirectional Protocol Independent Multicast (BIDIR-PIM)
【摘要或目录】：
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 ...................................................37
5. Security Considerations ........................................38
5.1. Attacks Based on Forged Messages ..........................38
5.1.1. Election of an Incorrect DF ........................38
5.1.2. Preventing Election Convergence ....................39
5.2. Non-Cryptographic Authentication Mechanisms ...............39
5.2.1. Basic Access Control ...............................39
5.3. Authentication Using IPsec ................................40
5.4. Denial-of-Service Attacks .................................40
6. IANA Considerations ............................................40
7. Acknowledgments ................................................40
8. Normative References ...........................................40
9. Informative References .........................................41
List of Figures
Figure 1. Downstream group per-interface state machine ............15
Figure 2. Upstream group state machine ............................17
Figure 3. Designated Forwarder election state machine .............27