IP Mobility Support for IPv4
RFC 3220

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Network Working Group                                    C. Perkins, Ed.
Request for Comments: 3220                         Nokia Research Center
Obsoletes: 2002                                             January 2002
Category: Standards Track

                      IP Mobility Support for IPv4

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.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document specifies protocol enhancements that allow transparent
   routing of IP datagrams to mobile nodes in the Internet.  Each mobile
   node is always identified by its home address, regardless of its
   current point of attachment to the Internet.  While situated away
   from its home, a mobile node is also associated with a care-of
   address, which provides information about its current point of
   attachment to the Internet.  The protocol provides for registering
   the care-of address with a home agent.  The home agent sends
   datagrams destined for the mobile node through a tunnel to the care-
   of address.  After arriving at the end of the tunnel, each datagram
   is then delivered to the mobile node.

Contents

   1. Introduction                                                     3
       1.1. Protocol Requirements . . . . . . . . . . . . . . . . .    4
       1.2. Goals . . . . . . . . . . . . . . . . . . . . . . . . .    4
       1.3. Assumptions . . . . . . . . . . . . . . . . . . . . . .    5
       1.4. Applicability . . . . . . . . . . . . . . . . . . . . .    5
       1.5. New Architectural Entities  . . . . . . . . . . . . . .    5
       1.6. Terminology . . . . . . . . . . . . . . . . . . . . . .    6
       1.7. Protocol Overview . . . . . . . . . . . . . . . . . . .    9
       1.8. Message Format and Protocol Extensibility . . . . . . .   13
       1.9. Type-Length-Value Extension Format for Mobile IP
               Extensions . . . . . . . . . . . . . . . . . . . . .   15
      1.10. Long Extension Format . . . . . . . . . . . . . . . . .   16

Perkins                     Standards Track                     [Page 1]
RFC 3220              IP Mobility Support for IPv4          January 2002

      1.11. Short Extension Format  . . . . . . . . . . . . . . . .   16
   2. Agent Discovery                                                 17
       2.1. Agent Advertisement . . . . . . . . . . . . . . . . . .   18
             2.1.1. Mobility Agent Advertisement Extension  . . . .   20
             2.1.2. Prefix-Lengths Extension  . . . . . . . . . . .   22
             2.1.3. One-byte Padding Extension  . . . . . . . . . .   22
       2.2. Agent Solicitation  . . . . . . . . . . . . . . . . . .   23
       2.3. Foreign Agent and Home Agent Considerations . . . . . .   23
             2.3.1. Advertised Router Addresses . . . . . . . . . .   24
             2.3.2. Sequence Numbers and Rollover Handling  . . . .   24
       2.4. Mobile Node Considerations  . . . . . . . . . . . . . .   25
             2.4.1. Registration Required . . . . . . . . . . . . .   26
             2.4.2. Move Detection  . . . . . . . . . . . . . . . .   26
             2.4.3. Returning Home  . . . . . . . . . . . . . . . .   27
             2.4.4. Sequence Numbers and Rollover Handling  . . . .   28
   3. Registration                                                    28
       3.1. Registration Overview . . . . . . . . . . . . . . . . .   29
       3.2. Authentication  . . . . . . . . . . . . . . . . . . . .   30
       3.3. Registration Request  . . . . . . . . . . . . . . . . .   30
       3.4. Registration Reply  . . . . . . . . . . . . . . . . . .   33
       3.5. Registration Extensions . . . . . . . . . . . . . . . .   36
             3.5.1. Computing Authentication Extension Values . . .   36
             3.5.2. Mobile-Home Authentication Extension  . . . . .   37
             3.5.3. Mobile-Foreign Authentication Extension . . . .   37
             3.5.4. Foreign-Home Authentication Extension . . . . .   38
       3.6. Mobile Node Considerations  . . . . . . . . . . . . . .   38
             3.6.1. Sending Registration Requests . . . . . . . . .   40
             3.6.2. Receiving Registration Replies  . . . . . . . .   43
             3.6.3. Registration Retransmission . . . . . . . . . .   46
       3.7. Foreign Agent Considerations  . . . . . . . . . . . . .   46
             3.7.1. Configuration and Registration Tables . . . . .   47
             3.7.2. Receiving Registration Requests . . . . . . . .   48
             3.7.3. Receiving Registration Replies  . . . . . . . .   51
       3.8. Home Agent Considerations . . . . . . . . . . . . . . .   53