[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-jang-mip6-hiopt) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 RFC 6610

MIP6 Working Group                                          Hee Jin Jang
Internet-Draft                                               Alper Yegin
Expires: June 22, 2007                                    JinHyeock Choi
                                                             SAMSUNG AIT
                                                        Kuntal Chowdhury
                                                        Starent Networks
                                                       December 19, 2006


          DHCP Option for Home Information Discovery in MIPv6
                      draft-ietf-mip6-hiopt-01.txt

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on June 22, 2007.

Copyright Notice

   Copyright (C) The Internet Society (2006).












Jang, et al.              Expires June 22, 2007                 [Page 1]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


Abstract

   This draft defines a DHCP-based scheme to enable dynamic discovery of
   Mobile IPv6 home agent address, home address, and home subnet.  New
   DHCP options are defined to carry the information from a DHCP server
   to the DHCP client running on the mobile node.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  DHCP options for HA Dynamic Discovery  . . . . . . . . . . . .  5
     3.1.  Home Network Identifier Option . . . . . . . . . . . . . .  5
     3.2.  Home Network Information Option  . . . . . . . . . . . . .  7
   4.  Option Usage . . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.1.  DHCP Server - Home Agent Relation  . . . . . . . . . . . . 10
     4.2.  Mobile Node Considerations . . . . . . . . . . . . . . . . 10
     4.3.  DHCP Server Considerations . . . . . . . . . . . . . . . . 11
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   6.  IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 13
   7.  Normative References . . . . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
   Intellectual Property and Copyright Statements . . . . . . . . . . 16



























Jang, et al.              Expires June 22, 2007                 [Page 2]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


1.  Introduction

   Before a mobile node can engage in Mobile IPv6 signaling with a home
   agent, it should either know the IP address of the home agent via
   preconfiguration, or dynamically discover it.  Mobile IPv6
   specification [2] describes how home agents can be dynamically
   discovered by mobile nodes that know the home subnet prefix.  This
   scheme does not work when prefix information is not already available
   to the mobile node.  This problem can be solved by delivering one or
   more home subnet prefix information to the mobile node by means of
   DHCP.  Subsequently, the mobile node can engage in dynamic home agent
   discovery using the prefix information.  In addition to delivering
   the prefix information, DHCP can also be used to provide the IP
   addresses or FQDNs of the home agents that are available to the
   mobile node and the home address that the mobile node can use to
   register with the home agent.

   The solution involves defining new DHCP options to carry home subnet
   prefix, home agent IP address, home agent's FQDN information, and
   home address of the mobile node.  A similar solution has already been
   defined for Mobile IPv4 home agents [3].

   As part of configuring the initial TCP/IP parameters, a mobile node
   can obtain home network information for the subnet it is directly
   attached to, other subnets in the visited domain, or a subnet from
   its home domain.  A mobile node can convey the target home subnet's
   identity in order to receive corresponding information.  For example
   the mobile node can provide realm portion of its user NAI (Network
   Access Identifier) and expect that a home network information from
   its home domain is returned.  The availability of the requested
   information depends on the DHCP server having prior knowledge or
   dynamically discovering it.  While the specific details are outside
   the scope of this document, use of static tables and AAA-assisted
   discovery are possible options [8].

   The mobile node may or may not be connected to the "home" subnet when
   it attempts to learn Mobile IPv6 home network information.  This
   allows operators to centrally deploy home agents while being able to
   bootstrap mobile nodes that are already roaming.  This scenario also
   occurs when HMIP [7] is used, where the mobile node is required to
   discover the MAP (a special home agent) that is located multiple hops
   away from the mobile node's attachment point.









Jang, et al.              Expires June 22, 2007                 [Page 3]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


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 RFC2119 [1].

   Most of terms used in this draft are defined in Mobile IPv6 [2] and
   RFC3315 [4].











































Jang, et al.              Expires June 22, 2007                 [Page 4]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


3.  DHCP options for HA Dynamic Discovery

   This section introduces two DHCP options used for dynamic home agent
   discovery in Mobile IPv6.

3.1.  Home Network Identifier Option

   This option is used to carry the identifier of the target home
   network.  This identification allows mobile node to request
   information for a home subnet within the visited domain, or from a
   specific domain.  It is assumed that the DHCP server has some
   mechanism to know or retrieve the requested Mobile IPv6 information
   such as [9].  The specifics of these mechanisms are outside the scope
   of this draft.

   The mobile node MUST include this option along with its Option
   Request option in its request.

       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_HNId             |           option-len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     id-type   |A|   reserved  |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
      |                                                               |
      .                                                               .
      .                    Home Network Identifier                    .
      +                                                               +
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                   Home Network Identifier Option Format



             option-code

                OPTION_HNId (TBD)

             option-len

                Total length of the option

             id-type

                The type of Home Network Identifier:




Jang, et al.              Expires June 22, 2007                 [Page 5]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


                        0    Visited (local) domain


                        1    Home domain


                        2    No preference

          A flag

             A flag to specify whether the client requests a home
             address or not.

          reserved

             7-bit field reserved for future use.  The value MUST be
             initialized to 0 by the sender, and MUST be ignored by
             the receiver.

          Home Network Identifier

             The identifier to specify the requested home network of the
             mobile node



   Id-type 0 indicates the mobile node is interested in learning the
   home network information that pertains to the immediately connected
   (visited) network.  In that case, Home Network Identifier field is
   not used.  This type can be used to discover local home agents in a
   visited network.

   Id-type 1 indicates the format of Home Network Identifier field is a
   network realm as defined in [5].  In this case, the mobile node is
   interested in learning home network information that pertains to the
   given realm.  This type can be used to discover home agents that are
   hosted by a user's home domain (as indicated by his/her NAI-based
   username -- user@HomeRealm).

   If the mobile node has no preference, the id-type is set to 2.  In
   this case, the assignment of the home network information is within
   the server's own discretion.

   If 'A' flag is set in this option, the server should assign a home
   address to the client in the returned Home Network Information
   option.  Otherwise, the server should not assign a home address
   option.




Jang, et al.              Expires June 22, 2007                 [Page 6]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


3.2.  Home Network Information Option

   This option is used to carry home network information to a mobile
   node in the form of one or more of home subnet prefix(es), home agent
   address(es), home agent FQDN(s), and mobile node's home address.

   The server MUST provide all of the matching home subnet prefix(es),
   home agent address(es) or FQDN(s) in a Home Network Information
   option.  If the server has no information to provide, it MUST set the
   option-len field to zero in this option.  If the client set the 'A'
   flag in Home Network Identifier option, it MUST provide an available
   home address to a client.

       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_HNInf          |           option-len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  hninfo-type  |  hninfo-len   |V|   reserved  |               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
      |                                                               |
      .                                                               .
      .                   Home Network Information                    .
      +                                                               +
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Home Network Information Option Format



            option-code

               OPTION_HNInf (TBD)

            option-len

               Total length of the option

            hninfo-type

               The type of the following Home Network Information field.
               Possible values are:

                       0    Home subnet prefix

                       1    Complete IPv6 address of the home agent




Jang, et al.              Expires June 22, 2007                 [Page 7]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


                         2    FQDN of the home agent

                         3    IPv6 Home address

            hninfo-len

               8-bit unsigned integer. Total length of the following
               Home Network Information field.

            V flag

               This flag specifies whether the home network information
               is assigned from the visited network or not.

            reserved

               7-bit field reserved for future use.  The value MUST be
               initialized to 0 by the sender, and MUST be ignored by
               the receiver.

            Home Network Information

               A home subnet prefix, home agent IP address, FQDN
               and home address to be assigned to a mobile node.

               When the hninfo-type is set to 0, the data field MUST
               contain the 8-bit prefix length information followed
               by the 128-bit IPv6 address beginning with the
               available network prefix.

               When the hninfo-type is set to 1, the data field MUST
               contain the 128-bit IPv6 address of the home agent.

               When the hninfo-type is set to 2, the data field MUST
               contain the FQDN as described in RFC1035 [6].

               When the hninfo-type is set to 3, the data field MUST
               contain the 8-bit reserved field, the 8-bit prefix length
               field of the following home address, the 32-bit lifetime
               of the following home address and the 128-bit home
               address to be assigned to a client. The lifetime is
               expressed in units of seconds.


   The home address, or hninfo-type = 3, should be included if and only
   if the client sets A flag in Home Network Identifier option.  Setting
   the lifetime to 0xffffffff ("infinity") means a permanent assignment
   of an address to the client.  The lifetime of the assigned home



Jang, et al.              Expires June 22, 2007                 [Page 8]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


   address should not be longer than the lifetime of its prefix since
   the home address cannot survive the prefix lifetime.

   If the id-type is set to 0 in the Home Network Identifier option, the
   server should reply with the available home agent(es) or home address
   information in the visited network and set the 'V' flag in the Home
   Network Information option.

   If the id-type is set to 1, the server should return that information
   in the specified home network in Home Network Identifier field in the
   request option.  In this case, the 'V' flag in Home Network
   Information option is set to 0.

   If the id-type is set to 2, the DHCP server replies with the home
   network information either from the home or from the visited network
   according to its policy or the home agent availability.  The 'V' flag
   in the Home Network Information option is set to 0 or 1 accordingly.

   Single option can carry multiple information preceded by hninfo-type
   and hninfo-len fields.  The length fields help identify the
   information boundaries.






























Jang, et al.              Expires June 22, 2007                 [Page 9]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


4.  Option Usage

   The requesting and sending of this option follows the rules for DHCP
   options in [4].

4.1.  DHCP Server - Home Agent Relation

   The DHCP server does not have to be co-located with a home agent, or
   even be on the home subnet of the mobile node.  Its location with
   respect to home network does not matter as long as it possesses the
   requested information.

4.2.  Mobile Node Considerations

   When a Mobile IPv6 mobile node finds itself with neither a home
   subnet prefix/home address nor a home agent address, it may request
   the needed information with Option Request option.  For instance, a
   mobile node connecting to a network for the first time may acquire a
   DHCP address and solicit for home network information at the same
   time.

   When a mobile node requests home network information form the DHCP
   server, it MUST clarify the preference of the requested home network
   with id-type in the request option.  If it has interest only in the
   currently visited network, it MUST set the id-type to 0.  If the
   mobile node has interest in the other specific network, it MUST
   identify the target network with Home Network Identifier option.  For
   example, a DHCP server may have information about home agents from
   several domains (and subnets).  Even when the mobile node does not
   care about the location of the home network where the home agent to
   be assigned, it MUST clarify the fact by setting the id-type to 3.
   In this case, the assignment of the home network information is based
   on the server's local policy.

   When the mobile node gets more than one home agent address, it MUST
   have a selection mechanism to determine which one to use for
   establishing a Mobile IPv6 session.  In case it retrieves only home
   subnet prefix(es), it needs to perform dynamic home agent discovery
   to learn the IP addresses of the home agents.  Similarly, if FQDN of
   a home agent is retrieved, the mobile node can use DNS to resolve it
   to IPv6 address(es) of the home agents.  If the mobile node receives
   both IPv6 address(es) and FQDN(s) of the home agents, it SHALL use
   the IPv6 information of the home agents.  When the mobile node
   requests and receives the home address information from the DHCP
   server, it SHALL use it to perform Mobile IPv6 home registration.
   For detailed mobile node behavior, refer to section 3.6 of [9].

   When the mobile node sends a Binding Update message to home agent by



Jang, et al.              Expires June 22, 2007                [Page 10]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


   using the home address which is assigned in Home Network Information
   option, the requested lifetime in Binding Update message MUST not be
   shorter than the lifetime of the home address.  Since the home
   address lifetime is not greater than its prefix lifetime, it is
   guaranteed that binding cache entry's lifetime is not greater than
   the home prefix lifetime.  Note that, according to 10.3.1 of MIPv6,
   the lifetime for the binding cache entry MUST NOT be greater than the
   remaining valid lifetime for the subnet prefix of the home address
   specified with the Binding Update.

4.3.  DHCP Server Considerations

   It is assumed that the DHCP server has access to home network
   information for its clients for this option to be useful.  The DHCP
   server can rely on pre-configuration, or some dynamic discovery
   mechanisms for obtaining this information.  In case it does not have
   any information, or it cannot locate matching information based on
   Home Network Identifier, it returns a Home Network Information option
   with 0-length data.  The DHCP server can either return the IPv6
   address(es) of home agent or the FQDN(s) of home agents.  It is not
   required for the DHCP server to return both.

   The DHCP server SHOULD have its own policy so that it can reply with
   the proper information in case a mobile node indicates no preference
   of the home network.  The policy can be determined based on several
   factors such as the home agent availability and the authorization
   information of the mobile node.  However, the specific policy setting
   is not in the scope of this document.

   When a DHCP server assigns a home address to an mobile node, it
   should guarantee that the lifetime of assigned home address MUST NOT
   be greater than that of the subnet prefix in the mobile node's home
   address.  The lifetimes of the home addresses for assignments are can
   be negotiated when the home prefix is delivered from the home agent,
   or configured by DHCP administrator's policy.  The details are
   outside the scope of this document.















Jang, et al.              Expires June 22, 2007                [Page 11]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


5.  Security Considerations

   Secure delivery of home agent, home address, and home link
   information from a DHCP server to the mobile node (DHCP client)
   relies on the overall DHCP security.  The particular option defined
   in this draft does not have additional impact on the DHCP security.

   Aside from the DHCP client to server interaction, an operator must
   also ensure secure delivery of mobile IP information to the DHCP
   server.  This is outside the scope of DHCP and the newly defined
   option.








































Jang, et al.              Expires June 22, 2007                [Page 12]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


6.  IANA Consideration

   This document introduces two new DHCPv6 options, Home Agent Request
   option and Home Agent Reply option.  The type numbers for new DHCP
   options are currently TBD.  An appropriate request will be made to
   IANA if this Internet draft gets accepted as an RFC.













































Jang, et al.              Expires June 22, 2007                [Page 13]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


7.  Normative References

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

   [2]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
        IPv6", RFC 3775, June 2004.

   [3]  Levkowetz, H., "DHCP Option for Mobile IP Mobility Agents",
        draft-ietf-dhc-mipadvert-opt-02 (work in progress),
        February 2004.

   [4]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M.
        Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
        RFC 3315, July 2003.

   [5]  Aboba, B. and M. Beadles, "The Network Access Identifier",
        RFC 2486, January 1999.

   [6]  Mockapetris, P., "Domain names - implementation and
        specification", STD 13, RFC 1035, November 1987.

   [7]  Soliman, H., Castelluccia, C., Malki, K., and L. Bellier,
        "Hierarchical Mobile IPv6 mobility management (HMIPv6)",
        draft-ietf-mipshop-hmipv6-04 (work in progress), December 2004.

   [8]  Chowdhury, K., "RADIUS Mobile IPv6 Support",
        draft-ietf-mip6-radius-01 (work in progress), October 2006.

   [9]  Chowdhury, K. and A. Yegin, "MIP6-bootstrapping via DHCPv6 for
        the Integrated Scenario",
        draft-ietf-mip6-bootstrapping-integrated-dhc-01 (work in
        progress), June 2006.


















Jang, et al.              Expires June 22, 2007                [Page 14]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


Authors' Addresses

   Hee Jin Jang
   Samsung Advanced Institute of Technology
   P.O. Box 111
   Suwon 440-600
   Korea

   Email: heejin.jang@samsung.com


   Alper E. Yegin
   Samsung Advanced Institute of Technology
   Istanbul
   Turkey

   Email: alper01.yegin@partner.samsung.com


   JinHyeok Choi
   Samsung Advanced Institute of Technology
   P.O. Box 111
   Suwon 440-600
   Korea

   Email: athene@sait.samsung.co.kr


   Kuntal Chowdhury
   Starent Networks
   30 International Place
   Tewksbury, MA  01876
   US

   Email: kchowdhury@starentnetworks.com
















Jang, et al.              Expires June 22, 2007                [Page 15]

Internet-Draft  DHCP Opt for Home Info Discovery in MIPv6  December 2006


Full Copyright Statement

   Copyright (C) The Internet Society (2006).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.


Acknowledgment

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).





Jang, et al.              Expires June 22, 2007                [Page 16]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/