Mobile IPv4 Regional Registration
RFC 4857

Network Working Group                                     E. Fogelstroem
Request for Comments: 4857                                    A. Jonsson
Category: Experimental                                          Ericsson
                                                              C. Perkins
                                                  Nokia Siemens Networks
                                                               June 2007

                   Mobile IPv4 Regional Registration

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 IETF Trust (2007).

Abstract

   Using Mobile IP, a mobile node registers with its home agent each
   time it changes care-of address.  This document describes a new kind
   of "regional registrations", i.e., registrations local to the visited
   domain.  The regional registrations are performed via a new network
   entity called a Gateway Foreign Agent (GFA) and introduce a layer of
   hierarchy in the visited domain.  Regional registrations reduce the
   number of signaling messages to the home network, and reduce the
   signaling delay when a mobile node moves from one foreign agent to
   another within the same visited domain.  This document is an optional
   extension to the Mobile IPv4 protocol.

Table of Contents

   1. Introduction ....................................................3
   2. Overview of Regional Registrations ..............................4
   3. Terminology .....................................................5
   4. Description of the Protocol .....................................7
      4.1. General Assumptions ........................................7
           4.1.1. Visited Domain ......................................8
           4.1.2. Authentication ......................................8
      4.2. Protocol Overview ..........................................9
      4.3. Advertising Foreign Agent and GFA .........................10
      4.4. Backwards Compatibility with RFC 3344 .....................10
   5. Home Registration ..............................................11
      5.1. Mobile Node Considerations ................................11

Fogelstroem, et al.           Experimental                      [Page 1]
RFC 4857           Mobile IPv4 Regional Registration           June 2007

      5.2. Foreign Agent Considerations ..............................12
      5.3. GFA Considerations ........................................13
      5.4. Home Agent Considerations .................................14
   6. Regional Registration ..........................................14
      6.1. Mobile Node Considerations ................................15
      6.2. Foreign Agent Considerations ..............................16
      6.3. GFA Considerations ........................................16
   7. Dynamic GFA Assignment .........................................17
      7.1. Mobile Node Considerations for Dynamic GFA Assignment .....17
      7.2. Foreign Agent Considerations for Dynamic GFA Assignment ...17
      7.3. GFA Considerations for Dynamic GFA Assignment .............18
      7.4. Home Agent Considerations for Dynamic GFA Assignment ......18
      7.5. Regional Registration .....................................19
   8. Router Discovery Extensions ....................................19
      8.1. Regional Registration Flag ................................19
      8.2. Foreign Agent NAI Extension ...............................19
   9. Regional Extensions to Mobile IPv4 Registration Messages .......20
      9.1. GFA IP Address Extension ..................................20
      9.2. Hierarchical Foreign Agent Extension ......................21
      9.3. Replay Protection Style ...................................22
      9.4. Regional Registration Lifetime Extension ..................23
      9.5. New Code Values for Registration Reply ....................24
   10. Regional Registration Message Formats .........................25
      10.1. Regional Registration Request ............................26
      10.2. Regional Registration Reply ..............................27
      10.3. New Regional Registration Reply Code Values ..............28
   11. Authentication Extensions .....................................29
   12. Security Considerations .......................................29
   13. IANA Considerations ...........................................30
   14. Acknowledgements ..............................................31
   15. References ....................................................32
      15.1. Normative References .....................................32