摘要

這篇文件描述的是IPv6的鄰居發現協議。在同一鏈路層上的IPv6節點通過鄰居發現去發現其他節點並決定彼此的Link-layer地址，發現路由器，還有維護可到達節點的路徑資訊。

譯者注

Table of Contents

   1. Introduction ....................................................4
   2. Terminology .....................................................4
      2.1. General ....................................................4
      2.2. Link Types .................................................8
      2.3. Addresses ..................................................9
      2.4. Requirements ..............................................10
   3. Protocol Overview ..............................................10
      3.1. Comparison with IPv4 ......................................14
      3.2. Supported Link Types ......................................16
      3.3. Securing Neighbor Discovery Messages ......................18
   4. Message Formats ................................................18
      4.1. Router Solicitation Message Format ........................18
      4.2. Router Advertisement Message Format .......................19
      4.3. Neighbor Solicitation Message Format ......................22
      4.4. Neighbor Advertisement Message Format .....................23
      4.5. Redirect Message Format ...................................26
      4.6. Option Formats ............................................28
           4.6.1. Source/Target Link-layer Address ...................28
           4.6.2. Prefix Information .................................29
           4.6.3. Redirected Header ..................................31
           4.6.4. MTU ................................................32
   5. Conceptual Model of a Host .....................................33
      5.1. Conceptual Data Structures ................................33
      5.2. Conceptual Sending Algorithm ..............................36
      5.3. Garbage Collection and Timeout Requirements ...............37
   6. Router and Prefix Discovery ....................................38
      6.1. Message Validation ........................................39
           6.1.1. Validation of Router Solicitation Messages .........39
           6.1.2. Validation of Router Advertisement Messages ........39
      6.2. Router Specification ......................................40
           6.2.1. Router Configuration Variables .....................40
           6.2.2. Becoming an Advertising Interface ..................45
           6.2.3. Router Advertisement Message Content ...............45
           6.2.4. Sending Unsolicited Router Advertisements ..........47
           6.2.5. Ceasing To Be an Advertising Interface .............47
           6.2.6. Processing Router Solicitations ....................48
           6.2.7. Router Advertisement Consistency ...................50
           6.2.8. Link-local Address Change ..........................50
      6.3. Host Specification ........................................51
           6.3.1. Host Configuration Variables .......................51
           6.3.2. Host Variables .....................................51
           6.3.3. Interface Initialization ...........................52
           6.3.4. Processing Received Router Advertisements ..........53
           6.3.5. Timing out Prefixes and Default Routers ............56
           6.3.6. Default Router Selection ...........................56
           6.3.7. Sending Router Solicitations .......................57
 

 7. Address Resolution and Neighbor Unreachability Detection .......59
      7.1. Message Validation ........................................59
           7.1.1. Validation of Neighbor Solicitations ...............59
           7.1.2. Validation of Neighbor Advertisements ..............60
      7.2. Address Resolution ........................................60
           7.2.1. Interface Initialization ...........................61
           7.2.2. Sending Neighbor Solicitations .....................61
           7.2.3. Receipt of Neighbor Solicitations ..................62
           7.2.4. Sending Solicited Neighbor Advertisements ..........63
           7.2.5. Receipt of Neighbor Advertisements .................64
           7.2.6. Sending Unsolicited Neighbor Advertisements ........66
           7.2.7. Anycast Neighbor Advertisements ....................67
           7.2.8. Proxy Neighbor Advertisements ......................68
      7.3. Neighbor Unreachability Detection .........................68
           7.3.1. Reachability Confirmation ..........................69
           7.3.2. Neighbor Cache Entry States ........................70
           7.3.3. Node Behavior ......................................71
   8. Redirect Function ..............................................73
      8.1. Validation of Redirect Messages ...........................74
      8.2. Router Specification ......................................75
      8.3. Host Specification ........................................76
   9. Extensibility - Option Processing ..............................76
   10. Protocol Constants ............................................78
   11. Security Considerations .......................................79
      11.1. Threat Analysis ..........................................79
      11.2. Securing Neighbor Discovery Messages .....................81
   12. Renumbering Considerations ....................................81
   13. IANA Considerations ...........................................83
   14. References ....................................................84
      14.1. Normative References .....................................84
      14.2. Informative References ...................................84
   Appendix A: Multihomed Hosts ......................................87
   Appendix B: Future Extensions .....................................88
   Appendix C: State Machine for the Reachability State ..............89
   Appendix D: Summary of IsRouter Rules .............................91
   Appendix E: Implementation Issues .................................92
   Appendix F: Changes from RFC 2461 .................................94
   Acknowledgments ...................................................95
 

1. Introduction 介紹

本規範定義了為IPv6協議制定的鄰居發現協議(Neighbor discovery, ND)