Fast Handovers for Mobile IPv6
RFC 4068

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• 03

Network Working Group                                     R. Koodli, Ed.
Request for Comments: 4068                         Nokia Research Center
Category: Experimental                                         July 2005

                     Fast Handovers for Mobile IPv6

Status of This Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   Mobile IPv6 enables a Mobile Node to maintain its connectivity to the
   Internet when moving from one Access Router to another, a process
   referred to as handover.  During handover, there is a period during
   which the Mobile Node is unable to send or receive packets because of
   link switching delay and IP protocol operations.  This "handover
   latency" resulting from standard Mobile IPv6 procedures, namely
   movement detection, new Care of Address configuration, and Binding
   Update, is often unacceptable to real-time traffic such as Voice over
   IP.  Reducing the handover latency could be beneficial to non-real-
   time, throughput-sensitive applications as well.  This document
   specifies a protocol to improve handover latency due to Mobile IPv6
   procedures.  This document does not address improving the link
   switching latency.

Koodli, Ed.                   Experimental                      [Page 1]
RFC 4068             Fast Handovers for Mobile IPv6            July 2005

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology. . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Protocol Overview. . . . . . . . . . . . . . . . . . . . . . .  5
       3.1.  Addressing the Handover Latency. . . . . . . . . . . . .  5
       3.2.  Protocol Operation . . . . . . . . . . . . . . . . . . .  7
       3.3.  Protocol Operation of Network-initiated Handover . . . .  9
   4.  Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 10
   5.  Miscellaneous. . . . . . . . . . . . . . . . . . . . . . . . . 15
       5.1.  Handover Capability Exchange . . . . . . . . . . . . . . 15
       5.2.  Determining New Care of Address. . . . . . . . . . . . . 15
       5.3.  Packet Loss. . . . . . . . . . . . . . . . . . . . . . . 15
       5.4.  DAD Handling . . . . . . . . . . . . . . . . . . . . . . 16
       5.5.  Fast or Erroneous Movement . . . . . . . . . . . . . . . 16
   6.  Message Formats. . . . . . . . . . . . . . . . . . . . . . . . 17
       6.1.  New Neighborhood Discovery Messages. . . . . . . . . . . 17
             6.1.1. Router Solicitation for Proxy Advertisement
                    (RtSolPr) . . . . . . . . . . . . . . . . . . . . 17
             6.1.2. Proxy Router Advertisement (PrRtAdv). . . . . . . 20
       6.2.  Inter-Access Router Messages . . . . . . . . . . . . . . 23
             6.2.1. Handover Initiate (HI). . . . . . . . . . . . . . 23
             6.2.2. Handover Acknowledge (HAck) . . . . . . . . . . . 25
       6.3.  New Mobility Header Messages . . . . . . . . . . . . . . 27
             6.3.1. Fast Binding Update (FBU) . . . . . . . . . . . . 27
             6.3.2. Fast Binding Acknowledgment (FBack) . . . . . . . 28
             6.3.3. Fast Neighbor Advertisement (FNA) . . . . . . . . 30
       6.4.  New Options. . . . . . . . . . . . . . . . . . . . . . . 31
             6.4.1. IP Address Option . . . . . . . . . . . . . . . . 32
             6.4.2. New Router Prefix Information Option. . . . . . . 33
             6.4.3. Link-Layer Address (LLA) Option . . . . . . . . . 34
             6.4.4. Mobility Header Link-Layer Address (MH-LLA)
                    Option. . . . . . . . . . . . . . . . . . . . . . 35
             6.4.5. Neighbor Advertisement Acknowledgment (NAACK) . . 35
   7.  Configurable Parameters. . . . . . . . . . . . . . . . . . . . 36
   8.  Security Considerations. . . . . . . . . . . . . . . . . . . . 37
   9.  IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 38
   10. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 39
   11. Normative References . . . . . . . . . . . . . . . . . . . . . 39
   12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 39

Koodli, Ed.                   Experimental                      [Page 2]
RFC 4068             Fast Handovers for Mobile IPv6            July 2005

1.  Introduction

   Mobile IPv6 [3] describes the protocol operations for a mobile node
   to maintain connectivity to the Internet during its handover from one
   access router to another.  These operations involve movement
   detection, IP address configuration, and location update.  The
   combined handover latency is often sufficient to affect real-time
   applications.  Throughput-sensitive applications can also benefit