Internet DRAFT - draft-yuchi-dhc-homeagent-opt

draft-yuchi-dhc-homeagent-opt



DHC WG                                                        Ma Yuzhi
Internet Draft                             Huawei Technologies CO.,LTD  
Expires: April 12, 2006                               October 13, 2005 
                                   
 
                                      
                Home Agent Configuration Option for DHCPv6 
                  draft-yuchi-dhc-homeagent-option-00.txt 


    

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Copyright Notice 

      Copyright (C) The Internet Society (2005).  All Rights Reserved. 

    

Abstract 

   This document defines a new home agent option for the Dynamic Host 
   Configuration Protocol for IPv6 (DHCPv6). To assist with rapid 

 
 
 
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   handovers the option allows a mobile node (DHCPv6 client) to acquire 
   a list of home agent addresses from a DHCPv6 server. 

 

Table of Contents 

    
   1. Introduction.................................................2 
   2. Terminology..................................................3 
   3. Home Agent Option............................................3 
   4. Client behavior..............................................4 
   5. Server behavior..............................................4 
   6. Relay agent behavior.........................................5 
   7. IANA Considerations..........................................5 
   8. Security Considerations......................................5 
   9. Acknowledgments..............................................5 
   10. References..................................................6 
      10.1. Normative References...................................6 
      10.2. Informative References.................................6 
   Author's Addresses..............................................6 
   Intellectual Property Statement.................................6 
   Disclaimer of Validity..........................................7 
   Copyright Statement.............................................7 
   Acknowledgment..................................................7 
    
    

1. Introduction 

   In Mobile IPv6, a mobile node needs to acquire its home address, 
   care-of address and home agent addresses. While away from home, the 
   mobile node registers its care-of address to its home agent, and then 
   the mobile node can communicate with a correspondent node. There are 
   two modes for communications between the mobile node and a 
   correspondent node. The first mode is bidirectional tunneling and the 
   second mode is route optimization. The mobile node can acquire its 
   home address or care-of address through conventional IPv6 mechanisms, 
   such as stateless or stateful auto-configuration.  

    The basic idea in Mobile IP is to allow a home agent to work as     
    a stationary proxy for a mobile node. In a Mobile IPv6 network 
    having steady home links, home agents can be configured on a DHCPv6 
    server, then a mobile node can acquire its home agent addresses when 
    it requests its home address from DHCPv6 server. It also can acquire 
    its home agent addresses when a mobile node is away from its home 
 
 
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    network and requests its care-of address. To assist with rapid 
    handovers, this document defines a new home agent option which can 
    be used to acquire a mobile node's home agent addresses.   
 

2. Terminology 

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 
   document are to be interpreted as described in RFC-2119 [1]. 

  Throughout this document, unless otherwise specified, the acronym 
   DHCP refers to DHCP for IPv6 (DHCPv6) as specified in RFC 3315. 
 
   This document uses terminology specific to IPv6 and DHCP as defined 
   in section "Terminology" of RFC 3315. 
    

3. Home Agent Option 

   The home agent option provides a list of one or more IPv6 addresses 
   of a mobile node's home agent. The home agent addresses are listed in 
   the order of preference for use by the mobile node. 

   The format of the home agent option is: 

   0                   1                   2                   3 
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |      OPTION_HOMEAGENT       |         option-len              | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                                                               | 
   |            option-data:home-agent-address1 (IPv6 address)     | 
   |             or home-address                                   | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                                                               | 
   |            option-data:home-agent-address2 (IPv6 address)     | 
   |                                                               | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                              ...                              | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
 
 
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    option-code:              OPTION_HOME_AGENT (TBD) 
 
    option-len:               Length of the list of home agent addresses    
                              in octets; must be a multiple of 16 
 
    option-data:              IPv6 addresses of a mobile node's home 
                              agents 

    

4. Client behavior 

   In a message sent by a mobile node (client) to a server, the option-
   len is set to 0 while the mobile node is on its home link. The 
   option-len is set to 16 while the mobile node is away from home, and 
   the option-data is set to the mobile node's home address. 

   When the mobile node(client) can acquire its home address or care-of 
   address through stateless auto-configuration, it SHOULD acquire its 
   home agent address using stateless DHCPv6.  

    

    

5. Server behavior 

   Every home agent's address and preference are predefined on a DHCPv6 
   server. These home agents are classified by the link prefix, and are 
   listed in order of preference value if there is more than one home 
   agent on the same link. 

   The following describes the behavior of a DHCPv6 server that 
   implements the home agent option when the client's message includes 
   the home agent option. 

   If the client's option-len is 0, the link prefix is used as the key 
   for searching home agent lists. The DHCPv6 server SHOULD create the 
   association of the home address with its home agent addresses. 

   If the client's option-len is 16, the home address is used as the key 
   for searching the above-mentioned association. 


 
 
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   In a message sent by a server to a mobile node (client), the option-
   data contains a list of IPv6 addresses which can serve as the home 
   agent for the mobile node. 

   Stateless DHCPv6 behavior will be specified in future. 

6. Relay agent behavior 

   A relay agent forwards messages containing the home agent option 
   in the same way as described in section 20, "Relay Agent Behavior" of 
   RFC 3315. 
    

7. IANA Considerations 

   IANA is requested to assign a DHCPv6 option code for the home agent 
   option. 

8. Security Considerations 

   Section 23 of [RFC 3315] outlines the DHCPv6 security considerations. 
   This option does not change the security of DHCPv6 in any significant 
   way. 

9. Acknowledgments 

    

 

















 
 
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10. References 

10.1. Normative References 

   [1]  Bradner, S., "Key words for use in RFCs to Indicate Requirement 
         Levels", BCP 14, RFC 2119, March 1997. 

   [2]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. 
         Carney, "Dynamic Host Configuration Protocol for IPv6 
         (DHCPv6)",RFC3315,July 2003. 

   [3]  Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in 
         IPv6", RFC3775, June 2004. 

10.2. Informative References 

   [4]  T. Chown, S. Venaas, A. Vijayabhaskar "Renumbering Requirements 
         for Stateless DHCPv6", Work in Progress, May 2005 

    

Author's Addresses 

   Ma Yuzhi 
   Huawei Bld., No.3 Xinxi Rd., 
   Shang Di Information Industry Base, 
   Hai-Dian District Beijing P.R.China 
      
   Email: myz@huawei.com 
 

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Acknowledgment 

   Funding for the RFC Editor function is currently provided by the 
   Internet Society. 















 
 
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