End-Host Mobility and Multihoming with the Host Identity Protocol
RFC 5206

Network Working Group                                        P. Nikander
Request for Comments: 5206                  Ericsson Research NomadicLab
Category: Experimental                                 T. Henderson, Ed.
                                                      The Boeing Company
                                                                 C. Vogt
                                                                J. Arkko
                                            Ericsson Research NomadicLab
                                                              April 2008

   End-Host Mobility and Multihoming with the Host Identity Protocol

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.

Abstract

   This document defines mobility and multihoming extensions to the Host
   Identity Protocol (HIP).  Specifically, this document defines a
   general "LOCATOR" parameter for HIP messages that allows for a HIP
   host to notify peers about alternate addresses at which it may be
   reached.  This document also defines elements of procedure for
   mobility of a HIP host -- the process by which a host dynamically
   changes the primary locator that it uses to receive packets.  While
   the same LOCATOR parameter can also be used to support end-host
   multihoming, detailed procedures are left for further study.

Table of Contents

   1.  Introduction and Scope . . . . . . . . . . . . . . . . . . . .  2
   2.  Terminology and Conventions  . . . . . . . . . . . . . . . . .  4
   3.  Protocol Model . . . . . . . . . . . . . . . . . . . . . . . .  5
     3.1.  Operating Environment  . . . . . . . . . . . . . . . . . .  5
       3.1.1.  Locator  . . . . . . . . . . . . . . . . . . . . . . .  7
       3.1.2.  Mobility Overview  . . . . . . . . . . . . . . . . . .  8
       3.1.3.  Multihoming Overview . . . . . . . . . . . . . . . . .  8
     3.2.  Protocol Overview  . . . . . . . . . . . . . . . . . . . .  9
       3.2.1.  Mobility with a Single SA Pair (No Rekeying) . . . . .  9
       3.2.2.  Mobility with a Single SA Pair (Mobile-Initiated
               Rekey) . . . . . . . . . . . . . . . . . . . . . . . . 11
       3.2.3.  Host Multihoming . . . . . . . . . . . . . . . . . . . 11
       3.2.4.  Site Multihoming . . . . . . . . . . . . . . . . . . . 13
       3.2.5.  Dual host multihoming  . . . . . . . . . . . . . . . . 14
       3.2.6.  Combined Mobility and Multihoming  . . . . . . . . . . 14

Nikander, et al.              Experimental                      [Page 1]
RFC 5206              HIP Mobility and Multihoming            April 2008

       3.2.7.  Using LOCATORs across Addressing Realms  . . . . . . . 14
       3.2.8.  Network Renumbering  . . . . . . . . . . . . . . . . . 15
       3.2.9.  Initiating the Protocol in R1 or I2  . . . . . . . . . 15
     3.3.  Other Considerations . . . . . . . . . . . . . . . . . . . 16
       3.3.1.  Address Verification . . . . . . . . . . . . . . . . . 16
       3.3.2.  Credit-Based Authorization . . . . . . . . . . . . . . 17
       3.3.3.  Preferred Locator  . . . . . . . . . . . . . . . . . . 18
       3.3.4.  Interaction with Security Associations . . . . . . . . 18
   4.  LOCATOR Parameter Format . . . . . . . . . . . . . . . . . . . 21
     4.1.  Traffic Type and Preferred Locator . . . . . . . . . . . . 23
     4.2.  Locator Type and Locator . . . . . . . . . . . . . . . . . 23
     4.3.  UPDATE Packet with Included LOCATOR  . . . . . . . . . . . 24
   5.  Processing Rules . . . . . . . . . . . . . . . . . . . . . . . 24
     5.1.  Locator Data Structure and Status  . . . . . . . . . . . . 24
     5.2.  Sending LOCATORs . . . . . . . . . . . . . . . . . . . . . 25
     5.3.  Handling Received LOCATORs . . . . . . . . . . . . . . . . 28
     5.4.  Verifying Address Reachability . . . . . . . . . . . . . . 30
     5.5.  Changing the Preferred Locator . . . . . . . . . . . . . . 31
     5.6.  Credit-Based Authorization . . . . . . . . . . . . . . . . 32
       5.6.1.  Handling Payload Packets . . . . . . . . . . . . . . . 32
       5.6.2.  Credit Aging . . . . . . . . . . . . . . . . . . . . . 33
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 34
     6.1.  Impersonation Attacks  . . . . . . . . . . . . . . . . . . 35
     6.2.  Denial-of-Service Attacks  . . . . . . . . . . . . . . . . 36
       6.2.1.  Flooding Attacks . . . . . . . . . . . . . . . . . . . 36
       6.2.2.  Memory/Computational-Exhaustion DoS Attacks  . . . . . 36
     6.3.  Mixed Deployment Environment . . . . . . . . . . . . . . . 37
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 37
   8.  Authors and Acknowledgments  . . . . . . . . . . . . . . . . . 38