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Versions: 00                                                            
autoconf Working Group                                    Jaehwoon Lee
Internet Draft                                      Dongguk University
Expires: August 17, 2009                                  Sanghynn Ahn
                                                   University of Seoul
                                                          Younghan Kim
                                                   Soongsil University
                                                            Yuseon Kim
                                                           Sangeon Kim
                                                                    KT
                                                     Febraury 18, 2009


           DHCP options for MANET prefix in connected MANET
               draft-jaehwoon-autoconf-dhcpoption-00.txt


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Abstract

   The mobile ad hoc network (MANET) is a wireless network composed of
   mobile nodes which can communicate with each other via multiple
   wireless links. The modified MANET architecture is now standardizing
   that can resolve the multi-link subnet issue. In this draft, we
   define two DHCP options in order that a MANET Router (MR) gets the
   network prefix assigned to the connected MANET. The one is the MANET
   prefix request option used by a MR when it wants to know the network
   presix allocated to the MANET. The other is the MANET prefix option
   that DHCP server provides the MANET prefix to the requesting MR.




Table of Contents


   1. Introduction..................................................3
   2. Terminology...................................................4
   3. DHCP option format............................................4
      3.1 MANET prefix Request option...............................4
      3.2 MANET prefix option.......................................4
   4. Option usage..................................................5
   5. Security Considerations.......................................6
   6. IANA Considerations...........................................6
   References.......................................................7
   Author's Addresses...............................................7
   Intellectual Property and Copyright Statements ..................9

















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1. Introduction


   The Mobile Ad hoc Network (MANET) is a wireless network composed of
   mobile nodes which can communicate with each other via multiple
   wireless links[1]. When two nodes not within their transmission range
   want to communicate, they have to communicate via wireless multiple
   hops. Thus a routing mechanism that can determine an end-to-end
   multi-hop wireless route between two nodes is required. However, it
   is also important an address auto-configuration mechanism that a node
   can automatically configure its address by itself.

   From the extenal connectivity point of view, the MANET can be
   classified into the standalone MANET and the connected MANET[2].
   Standalone MANET is the MANET not connected to the global Internet.
   On the other hand, the connected MANET is the MANET connected to the
   global Internet by using the MANET border router (MBR). In the
   connected MANET, one communicating with an end host is a MANET node
   and the other end can be a MANET node within the same MANET or a host
   within the Internet. Nodes in a connected MANET should be allocated
   with Internet topologically correct global IP addresses.

   Previous researches on the MANET have considered an MANET as a single
   subnetwork, so all nodes in a MANET are assigned the same subnet
   prefix, which is the multi-link subnet model. Recently, an Internet
   document considering the issues that can occur in a multi-link subnet
   was standardized[3]. In accordance with the documnet, the modified
   MANET architecture that defines a MANET node (MN) as a composite of
   one MANET router (MR) and zero or more hosts is currently on the
   standardization process[4]. That is, a MANET is defined as a network
   composed of multiple MRs connected via wireless links. An MR should
   know the network prefix allocated to the MANET that it is connected.
   However, till now there is no method to define how to know the
   MANET's network prefix.

   In this draft, we define the DHCP options for an MR to get network
   prefix allocated to the connected MANET.


2. Terminology

   MANET Prefix    The network prefix assigned to the connected MANET




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3. Option Format

3.1 DHCP option for MANET prefix request

   The option is used to request the network prefix assigned to the
   MANET. The format of the MANET prefix request 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 code           |          Option length        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Reserved (4 octets)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   DHCP option Fields:

      Option code           TBD (MANET Prefix Request)

      Option length         4



3.2 DHCP option for MANET prefix

   The option is used to provide the network prefix assigned to the
   MANET. The format of the MANET prefix 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 code          |        Option length          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Prefix length |                                               |
      +-+-+-+-+-+-+-+-+                                               |
      |                      MANET Prefix                             |
      |                       (16 octets)                             |
      |                                                               |
      |                                                               |
      |               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               |
      +-+-+-+-+-+-+-+-+


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   DHCP option Fields:

      Option code           TBD (MANET Prefix)

      Option length         17

      Prefix length         Length for the MANET prefix in bits

      MANET prefix          Network prefix assigned to the MANET


4. Option usage


                 +--------------+
                /                \      +----+
               +     Internet     +-----+Host+
                \                /      +----+
                 +-------+------+
                         |
                       +-+-+       (Mobile Ad Hoc Network)
     +-----------------+MBR+-------------------------------------------+
     |                 +-+-+       MANET Prefix: 2008:1234::/32        |
     |                   |                                +------+     |
     |                   |                            +---+Host11|     |
     |                 +-+-+                          |   +------+     |
     |                 |MR1+--------------------------+                |
     |                 +-+-+                          |   +------+     |
     |                   |                            +---+Host12|     |
     |                   |                                +------+     |
     |                   | Network prefix for MR1's IP interface:      |
     |                   |       2008:1234:5678:9ABC::/64              |
     |                   |                                +------+     |
     |                   |                            +---+Host21|     |
     |                 +-+-+                          |   +------+     |
     |                 |MR2+--------------------------+                |
     |                 +-+-+                          |   +------+     |
     |                                                +---+Host22|     |
     |                                                    +------+     |
     |                     Network prefix for MR2's IP interface:      |
     |                           2008:1234:5678:9ABD::/64              |
     +-----------------------------------------------------------------+
         Figure 1. An example of address configuration in the MANET



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   Figure 1 shows an address autoconfiguration example of a MANET based
   on the modified MANET architecture. An MR has two types of
   interfaces, one or more MANET interfaces and zero or more IP
   interfaces. The MANET interface is used to communicate with other MRs
   and the IP interface is connected to the hosts. The MANET and the
   IP interfaces should be allocated with different network prefixes.
   How to assign a network prefix to a MANET interface is out of the
   scope of this draft. One possible method is to use the scope-extended
   Router Advertisement (SERA) ICMP message[5]. Moreover, different IP
   interfaces should be allocated with different network prefixes. How
   to assign a network prefix to an IP interface is out of the scope of
   this draft. One possible method is to use the DHCP prefix option[6].

   The network prefixes allocated to IP interfaces should be subset of
   the network prefix allocated to the MANET, that is, MANET prefix.
   How an MR gets the MANET prefix is described in this draft.

   An MR send an DHCP request message containing MANET prefix request
   option in order to get the network prefix allocated to the MANET.
   The option format is defined in Section 3.1. The DHCP server sends a
   DHCP reply message including the MANET prefix option containing the
   MANET prefix in response to the MANET prefix request option. The
   option format for the MANET prefix option is defined in Section 3.2.
   How to use the MANET prefix by an MR is out of the scope of this
   draft. One possibility is that an MR within an MANET can decide
   whether the destination host resides in the same MANET based on the
   destination address of the received IP packet.



5. Security Consideration

   TBD.


6. IANA Considerations

   TBD.







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References

   [1] C. Perkins, Ad Hoc Networking, Addison Wesley, 2001.

   [2] C. Bernardos, M. Calderon and H. Moustafa, "Survey of IP address
       autoconfiguration mechanisms for MANETs",
       draft-bernardos-manet-autoconf-survey-04, work in progress,
       Nov. 2008.

   [3] D. Thaler, "Multi-Link Subnet Issues", RFC 4903, June 2007.

   [4] I. Chakeres, J. Macker and T. Clausen, "Mobile Ad hoc Network
       Architecture", draft-ietf-autoconf-manetarch-07,
       Work in progress, Nov. 2007.

   [5] J. Lee, S. Ahn, Y. Kim, Y. Kim and S. Kim, "Scope-extended router
       advertisement for connected MANETs",
       draft-jaehwoon-autoconf-sera-01, work in progress, Oct. 2008.

   [6] O. Troan and R. Droms, "IPv6 Prefix Options for Dynamic Host
       Configuration Protocol (DHCP) version 6", RFC 3633, Dec. 2003.


Author's Addresses

   Jaehwoon Lee
   Dongguk University
   26, 3-ga Pil-dong, Chung-gu
   Seoul 100-715, KOREA
   Email: jaehwoon@dongguk.edu

   Sanghyun Ahn
   University of Seoul
   90, Cheonnong-dong, Tongdaemun-gu
   Seoul 130-743, KOREA
   Email: ahn@uos.ac.kr

   Younghan Kim
   Soongsil University
   11F Hyungnam Engineering Bldg. 317, Sangdo-Dong,
   Dongjak-Gu, Seoul 156-743 Korea
   E-main: yhkim@dcn.ssu.ac.kr



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Internet-Draft       DHCP options for MANET prefix     Febraury 18, 2009

   Yuseon Kim
   KT
   17 Woomyeon-dong, Seocho-gu
   Seoul 137-792, KOREA
   Email: yseonkim@kt.co.kr

   Sangeon Kim
   KT
   17 Woomyeon-dong, Seocho-gu
   Seoul 137-792, KOREA
   Email: sekim@kt.co.kr




































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