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Versions: 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 RFC 5678

Internet Engineering Task force                           Gabor Bajko
Internet Draft                                                  Nokia
Intended Status: Proposed Standard                          Subir Das
Expires: September 24, 2009                    Telcordia Technologies
                                                       March 25, 2009


Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Options for
                    IEEE 802.21 Mobility Services (MoS) Discovery
                    draft-ietf-mipshop-mos-dhcp-options-12

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with
   the provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 24, 2009.

Copyright and License Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
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   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.


Abstract

   This document defines new Dynamic Host Configuration Protocol
   (DHCPv4 and DHCPv6) options that contain a list IP addresses and a
   list of domain names that can be mapped to servers providing IEEE

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   802.21 type of Mobility Service (MoS)[MSFD]. These Mobility
   Services are used to assist an MN in handover preparation (network
   discovery) and handover decision (network selection). The services
   addressed in this document are the Media Independent Handover
   Services defined in [IEEE802.21].


 (1) Conventions used in this document

   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.

 (2) Terminology and abbreviations used in this document

   Mobility Services: a set of different services provided by the
   network to mobile nodes to facilitate handover preparation
   and handover decision. In this document, Mobility Services refer to
   the services defined in IEEE 802.21 specifications [IEEE802.21]

   Mobility Server: a network node providing Mobility Support Services.

   MIH: Media Independent Handover, as defined in [IEEE802.21].

   MIH Service: IS, ES or CS type of service, as defined in
   [IEEE802.21]

Table of Contents

   1. Introduction .................................................2
   2. MoS IPv4 address option for DHCPv4............................3
   3. MoS Domain Name List option for DHCPv4........................5
   4. MoS IPv6 address option for DHCPv6............................7
   5. MoS Domain Name List option for DHCPv6........................9
   6. Option Usage.................................................10
        6.1 Usage of MoS Options for DHCPv4........................10
        6.2 Usage of MoS Options for DHCPv6........................11
   7. Security Considerations .....................................12
   8. IANA Considerations .........................................12
   9. Acknowledgements ............................................13
   10. References .................................................13
       10.1 Normative References ..................................13
       10.2 Informative References ................................13
   Author's Addresses .............................................13




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1. Introduction

   IEEE 802.21 [IEEE802.21] defines three distinct service types to
   facilitate link layer handovers across heterogeneous technologies:

   a) Information Services (IS)
        IS provides a unified framework to the higher layer entities
   across the heterogeneous network environment to facilitate
   discovery and selection of multiple types of networks existing
   within a geographical area, with the objective to help the higher
   layer mobility protocols to acquire a global view of heterogeneous
   networks and perform seamless handover across these networks.

     b) Event Services (ES)
        Events may indicate changes in state and transmission behavior
   of the physical, data link and logical link layers, or predict state
   changes of these layers. The Event Service may also be used to
   indicate management actions or command status on the part of the
   network or some management entity.

   c) Command Services (CS)
        The command service enables higher layers to control the
   physical, data link, and logical link layers. The higher layers may
   control the reconfiguration or selection of an appropriate link
   through a set of handover commands.

   In IEEE terminology these services are called Media Independent
   Handover (MIH) services. While these services may be co-located,
   the different pattern and type of information they provide does not
   necessitate the co-location.

   An MN may make use of any of these MIH service types separately or
   any combination of them [MSFD]. In practice a Mobility Server may
   not necessarily host all three of these MIH services together, thus
   there is a need to discover the MIH services types separately.

   This document defines new DHCPv4 and DHCPv6 options and sub-options
   called the MoS IP Address and Domain Name List Options, which allow
   the MN to locate a Mobility Server which hosts the desired service
   type (i.e. IS, ES or CS) as defined in [IEEE802.21]. Apart from
   manual configuration, this is one of the possible solutions for
   locating a server providing Mobility Services.

2. MoS IPv4 Address Option for DHCPv4

   This section describes the MoS IPv4 Address Option for DHCPv4.
   Whether the MN receives an MoS address from local or home network
   will depend on the actual network deployment [MSFD]. The MoS IPv4


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   Address Option begins with a option code followed by a length and
   sub-options. The value of the length octet does not include itself
   or the option code. The option layout is depicted below:

     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 Code   |    Length     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option 1                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       ...                                     |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option n                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


         Option Code

                OPTION-IPv4_Address-MoS (To Be Assigned) - 1 byte

         Length

                An 8-bit field indicating the length of the option
                excluding the 'Option Code' and the 'Length' fields

         Sub-options

                A series of DHCPv4 sub-options

   When the total length of a MoS IPv4 Address Option exceeds 254
   octets, the procedure outlined in [RFC3396] MUST be employed to
   split the option into multiple, smaller options.

   A sub-option begins with a sub-option code followed by a length
   and one or more IPv4 addresses.  The sub-option layout is
   depicted below:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Sub-opt Code  |    Length     |    IP Address . . . . .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               .
      .                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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 The sub-option Codes are summarized below.
      +--------------+---------------+
      |  Sub-opt     | Service       |
      |   Code*      | Name          |
      +==============+===============+
      |    1         |   IS          |
      +--------------+---------------+
      |    2         |   CS          |
      +--------------+---------------+
      |    3         |   ES          |
      +--------------+---------------+

*Note: The values `0` '4' to '255' are reserved and MUST NOT be used.

If the length is followed by a list of IPv4 addresses indicating
appropriate MIH servers available to the MN, servers MUST be listed in
order of preference. Its minimum length is 4, and the length MUST be a
multiple of 4. The sub-option has the following format:

           Code Len   IPv4 Address 1    IPv4 Address 2
         +-----+---+---+----+----+----+----+----+---
         |1..3 | n |a1 | a2 |a3  | a4 | a1 |  ...
         +-----+---+---+----+----+----+-----+----+--



3. MoS Domain Name List Option for DHCPv4

   This section describes the MoS Domain Name List Option for DHCPv4.
   The general format of this option is depicted below:

     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 Code   |    Length     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option 1                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       ...                                     |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option n                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Option Code

                OPTION-IPv4_FQDN-MoS (To Be Assigned) - 1 byte

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     Length
                An 8-bit field indicating the length of the option
                excluding the 'Option Code' and the 'Length' fields

         Sub-options

                A series of DHCPv4 sub-options.

   When the total length of a MoS Domain Name List Option exceeds 254
   octets, the procedure outlined in [RFC3396] MUST be employed to
   split the option into multiple, smaller options.

   A sub-option begins with a sub-option Code followed by a length
   and one or more FQDNs.  The sub-option layout is depicted below:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Sub-opt Code  |    Length     |  FQDN(s) . . . . . .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               .
      .                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The sub-option Codes are summarized below.
      +--------------+---------------+
      |  Sub-opt     | Service       |
      |   Code*      | Name          |
      +==============+===============+
      |    1         |   IS          |
      +--------------+---------------+
      |    2         |   CS          |
      +--------------+---------------+
      |    3         |   ES          |
      +--------------+---------------+

*Note: The values `0` '4' to '255' are reserved and MUST NOT be used.

Thus the sub-option for this encoding has the following format:

           Code  Len   DNS name of MoS server
         +-----+----+----+-----+-----+-----+-----+--
         |1..3 | n  | s1 |  s2 |  s3 |  s4 | s5  |  ...
         +-----+----+----+-----+-----+-----+-----+--


   The Sub-option begins with a sub-option code followed by a length
   and a sequence of labels that are encoded according to Section 8 of
   [RFC3315].


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   The Sub-option MAY contain multiple domain names, but these should
   Refer to the NAPTR records of different providers, rather than
   different A records within the same provider. That is, the use of
   multiple domain names is not meant to replace NAPTR and SRV records,
   but rather to allow a single DHCP server to indicate MIH servers
   operated by multiple providers.

   The client MUST try the records in the order listed, applying the
   mechanism described in [MoS-DNS] for each. The client only resolves
   the subsequent domain names if attempts to contact the first one
   failed or yielded no common transport protocols between the MN and
   the server.

   As an example, consider the case where the server wants to offer
   two MIH IS servers, "example.com" and "example.net".  These would
   be encoded as follows:
   +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   |1..3 |26 | 7 |'e'|'x'|'a'|'m'|'p'|'l'|'e'| 3 |'c'|'o'|'m'| 0 |
   +-----+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   +---+---+---+---+---+---+---+---+---+---+---+---+---+
   | 7 |'e'|'x'|'a'|'m'|'p'|'l'|'e'| 3 |'n'|'e'|'t'| 0 |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+


4. MoS IPv6 Address Option for DHCPv6

   This section describes the MoS IPv6 Address Option for DHCPv6.
   Whether the MN receives an MoS address from local or home network
   will depend on the actual network deployment [MSFD]. The MoS
   Discovery Option begins with a option code followed by a length
   and sub-options. The value of the length octet does not include
   itself or the option code. The option layout is depicted below:

     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 Code             |           Length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option 1                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       ...                                     |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option n                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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       Option Code

             OPTION-IPv6_Address-MoS (To Be Assigned) - 2 bytes

       Length

             A 16-bit field indicating the length of the option
             excluding the 'Option Code' and the 'Length' fields.

       Sub-options

             A series of DHCPv6 sub-options

   The sub-options follow the same format (except the Sub-opt Code and
   Length value) as described in Section 2. The value of the Sub-opt
   Code and Length are 2-octets and the Length does not include itself
   or the Sub-opt Code field. The sub-option layout is depicted below:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | sub-opt Code                  |     Length                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                   IP Address                                  |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  The sub-option Codes are summarized below.
      +----------------+---------------+
      |  Sub-opt Code* | Service Name  |
      +================+===============+
      |    1           |   IS          |
      +----------------+---------------+
      |    2           |   CS          |
      +----------------+---------------+
      |    3           |   ES          |
      +----------------+---------------+
*Note: The values `0` '4' to '65535' are reserved and MUST NOT be
used.


5. MoS Domain Name List option for DHCPv6

   This section describes the MoS Domain List Option for DHCPv6. The
   general format of this option for is depicted below:





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      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 Code             |           Length              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option 1                               |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       ...                                     |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Sub-Option n                              |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Option Code

             OPTION-IPv6_FQDN-MoS (To Be Assigned) - 2 bytes

       Length

             A 16-bit field indicating the length of the option
             excluding the 'Option Code' and the 'Length' fields.

       Sub-options

             A series of DHCPv6 sub-options

   The Sub-options follow the same format (except the Sub-opt Code and
   Length value) as described in Section 3. The value of the Sub-opt
   Code and Length are 2-octets and the Length does not include itself
   or the Sub-opt Code field. The sub-option layout is depicted below:

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | sub-opt Code                  |     Length                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                   FQDN(s)                                     |
     .                                                               .
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      +----------------+---------------+
      |  Sub-opt Code* | Service Name  |
      +================+===============+
      |    1           |   IS          |
      +----------------+---------------+
      |    2           |   CS          |
      +----------------+---------------+
      |    3           |   ES          |
      +----------------+---------------+

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   *Note: The values `0` '4' to '65535' are reserved and MUST NOT be
   used.

  The sub-option Codes are summarized below.

   The semantics and content of the DHCPv6 encoding of this option are
   exactly the same as the encoding described in Section 3, except the
   Option Code and Length value.



6. Option Usage

6.1 Usage of MoS Options for DHCPv4

   The requesting and sending of the proposed DHCPv4 options follow
   the rules for DHCP options in [RFC2131].

6.1.1 Mobile Node behavior

   The mobile node may perform a MoS discovery either during initial
   association with a network or when the mobility service is required.
   It may also try to perform the MoS discovery when it lacks the
   network information for MoS or needs to change the MoS for some
   reasons, for instance, to recover from the single point of failure
   of the existing MoS.

   In order to discover the IP address or domain name of a MoS Server,
   the mobile node(DHCP client) MUST include either a MoS IPv4 Address
   Option or a MoS Domain Name List Option in the respective DHCP
   messages as defined in [RFC2131]. The requested options MUST
   include one or more sub-option(s) with the Sub-opt Code(s) that
   represents the service(s)the mobile node is interested in.

6.1.2 DHCP Server behavior

   When the DHCP server receives either a MoS IPv4 Address Option or a
   MoS Domain Name List Option, the DHCP server MUST always construct
   the response messages (as defined in [RFC 2131]) according to the
   sub-option code(s) representing the service(s) desired by the mobile
   node in the Sub-option Code field(s). Each sub-option in a response
   message may contain a list of one or more IP addresses or a list of
   one or more FQDNs of the MoS server hosting the desired service.

   In case that the server cannot find any Mobility Server satisfying
   the requested Sub-opt Code, the server MUST return the MoS Option
   with a sub-option by setting the Sub-opt Code to the requested
   Sub-opt Code.



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6.2 Usage of MoS Options for DHCPv6

   The requesting and sending of the proposed DHCPv6 options follow
   the rules for DHCP options in [RFC3315].

6.2.1 Mobile node behavior

   The mobile node may perform the MoS discovery either during initial
   association with a network or when the mobility service is required.
   It may also try to perform the MoS discovery when it lacks the
   network information for MoS or needs to change the  MoS for some
   reasons, for instance, to recover from the single point of failure
   of the existing MoS.

   In order to discover the IP address or FQDN of a MoS, the mobile
   node(DHCP client) MUST include either a MoS IPv6 Address Option
   or a MoS Domain Name List Option in the respective DHCP messages
   as defined in [RFC3315]. The requested MoS Option MUST
   include one or more sub-option(s) with the Sub-opt Code(s) that
   represents the service(s) the mobile node is interested in.

6.2.2 DHCP Server behavior

   When the DHCP Server receives either a MoS IPv6 Address Option or
   a MoS Domain Name List Option, the DHCP server MUST always construct
   the response messages (as defined in RFC3315]), according to the sub-
   option code(s) representing the service(s) desired by the mobile node
   in the Sub-option code field(s). Each Sub-option in a response
   message may contain a list of one or more IP addresses or a list of
   one or more FQDNs of the MoS server hosting the desired service.

   In case that the server cannot find any Mobility Server satisfying
   the requested Sub-opt Code, the server MUST return the MoS Option
   with a sub-option by setting the Sub-opt Code to the requested
   Sub-opt Code.



7. Security Considerations

   The security considerations in [RFC2131] apply. If an adversary
   manages to modify the response from a DHCP server or insert its own
   response, an MN could be led to contact a rogue Mobility Server,
   possibly one that then would provide wrong information, event or
   command for handover.




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   It is recommended to use either DHCP authentication option described
   in [RFC3118] where available, or rely upon link layer security.

   This will also protect the denial of service attacks to DHCP
   servers. [RFC3118] provides mechanisms for both entity
   authentication and message authentication.


8. IANA Considerations

   This document defines two new DHCPv4 options as described in Sections
   2 and 3.

   MoS IPv4 Address Option for DHCPv4 (OPTION-IPv4_Address-MoS)    TBA

   MoS Domain Name List option for DHCPv4 (OPTION-IPv4_FQDN-MoS)   TBA

   This document creates a new registry for the Sub-Option fields in
   the MoS DHCPv4 Address and FQDN options called the "IEEE 802.21
   Service Type" (Section 2 and 3).

      IS                       1
      CS                       2
      ES                       3


  The values '0', '4' to '255' are reserved and MUST NOT be used. New
  values can be allocated by Standards Action or IESG approval.

  This document also defines two DHCPv6 options as described in
  sections 4 and 5.

   MoS IPv6 Address Option for DHCPv6 (OPTION-IPv6_Address-MoS)   TBA

   MoS Domain Name List option for DHCPv6 (OPTION-IPv6_FQDN-MoS)  TBA

   This document creates a new registry for the sub-option field in
   the MoS DHCPv6 Address and FQDN options called the "IEEE 802.21
   Service Type" (Section 4 and 5).


        IS                       1
        CS                       2
        ES                       3

  The values '0', '4' to '65535' are reserved and MUST NOT be used.
  New Values can be allocated via Standards Action as defined
  in [RFC5226].


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9. Acknowledgements

   Authors would like to acknowledge the following individuals for
   their valuable comments.
   Alfred Hoenes, Bernie Volz, , David W. Hankins, Jari Arkko,
   Telemaco Melia, Ralph Droms Ted Lemon Vijay Devarapalli,  and
   Yoshihiro Ohba


10. References

    10.1 Normative References

   [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
      2131, March 1997.

   [RFC3315] Dynamic Host Configuration Protocol for IPv6 (DHCPv6),
      Droms et al, July 2003

   [RFC3118] Authentication for DHCP Messages, Droms et al, June 2001

   [RFC3396] Lemon, T. and S. Cheshire, "Encoding Long DHCP Options",
      RFC3396, November 2002.

   [RFC5226] T. Narten and H. Alvestrand, "Guidelines for Writing an
    IANA  Considerations Section in RFCs" , May 2008.

   [MSFD] T Melia, Ed., " Mobility Services Framework Design (MSFD)",
      draft-ietf-mipshop-mstp-solution-12.txt (Work in Progress).

   [MoS-DNS] Bajko, G., "Locating Mobility Servers",
      draft-ietf-mipshop-mos-dns-discovery-04.txt (Work in Progress),


   10.2 Informative References

   [IEEE802.21] IEEE 802.21 Standard for Local and Metropolitan Area
      Networks: Media Independent Handover Services


Authors' Addresses

   Gabor Bajko
   Nokia
   e-mail: gabor.bajko@nokia.com

   Subir Das
   Telcordia Technologies Inc.
   e-mail: subir@research.telcordia.com

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