[Search] [txt|pdf|bibtex] [Tracker] [Email] [Nits]

Versions: 00 01                                                         
Network Working Group                                            H. Deng
Internet-Draft                                              China Mobile
Intended status: Standards Track                            July 2, 2008
Expires: January 3, 2009


       DHCP Based Configuration of Mobile Node from Home Network
                 draft-deng-mip4-host-configuration-00

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 January 3, 2009.


















Deng                     Expires January 3, 2009                [Page 1]


Internet-Draft            DHCP MN Configuration                July 2008


Abstract

   This document describes the mechanism for providing the host
   configuration parameters needed for network service from home network
   based on DHCPINFORM.  DHCPINFORM message has been widely used by
   client to obtain other configuration information and could be sent to
   local broadcast address or server unicast address.  Mobile IP
   specification could support DHCPINFORM broadcast or unicast message
   straightfully without any revision.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Home DHCP server's address unknown . . . . . . . . . . . . . .  4
     2.1.  MIP4 Co-CoA case . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  MIP4 FA CoA Case . . . . . . . . . . . . . . . . . . . . .  8
   3.  Home DHCP server's address known . . . . . . . . . . . . . . . 13
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   5.  IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 17
   6.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 18
   7.  Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 19
   8.  Normative References . . . . . . . . . . . . . . . . . . . . . 20
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 21
   Intellectual Property and Copyright Statements . . . . . . . . . . 22


























Deng                     Expires January 3, 2009                [Page 2]


Internet-Draft            DHCP MN Configuration                July 2008


1.  Introduction

   Mobile node could use DHCP mechanism to configure local information
   when it attach to the foreign network.  But it may have to get
   configuration information from the home network as well.  The common
   mechanism to configure the mobile host is preferable in Mobile IP.

   If a mobile node has obtained a network address through some other
   means, it may use a DHCPINFORM request message to obtain other local
   configuration parameters.  This DHCPINFORM message could be sent to
   local broadcast address or server unicast address(know it from out of
   band delivery).  DHCP Server receiving a DHCPINFORM message construct
   a DHCPACK message with any local configuration parameters appropriate
   for the mobile node.

   This document has analysed the process about how Mobile IP
   specification could straightfully support DHCPINFORM broadcast or
   unicast message for host configuration without any revision.

































Deng                     Expires January 3, 2009                [Page 3]


Internet-Draft            DHCP MN Configuration                July 2008


2.  Home DHCP server's address unknown

2.1.  MIP4 Co-CoA case

   If the 'D' bit was set in the mobile node's Registration Request
   message, and code field of the received registration reply indicate
   successly registered.  This means that the mobile node is using a co-
   located care-of address.

   Section 5.3 of Reverse tunneling [RFC3024] recommend that a mobile
   node using a co-located care-of address send the broadcast/multicast
   packet are handled according to Sections 4.3 and 4.4 of the Mobile IP
   specification [RFC3344].

   Section 4.3 of [RFC3344] doesn't specify how a mobile node send
   datagrams to a broadcast address in detail.  Section 4.4 of [RFC3344]
   specify that a mobile node which tunnels a multicast datagram to its
   home agent MUST use its home address as the IP source address of both
   the (inner) broadcast datagram and the (outer) encapsulating
   datagram.  Anyway this tunnel is not topologically correct.

   The mobile node simply tunnels appropriate broadcast DHCPINFORM
   message to the home agent.The source address of this DHCPINFORM
   message is the mobile node's home address.  Home agent just work as a
   simple DHCP relay agent as shown in figure 1.

                     +-----+    +-------+
                     | HA/ |    | Home  |
                     |DHCP |----| DHCP  |
                     |Relay|    | Server|
                     +-----+    +-------+
                      //
                     //   Home Network
       -------------//-----------------------
                   //   Visiting Network
                  //
                 //     +----+
              +----+    |    |
              | MN |----| AR |
              +----+    |    |
                        +----+

        Figure 1: Home network configuration in the case of Co-CoA








Deng                     Expires January 3, 2009                [Page 4]


Internet-Draft            DHCP MN Configuration                July 2008


      +----+                     +-------+   +------+
      |    |                     |  HA   |   |DHCP  |
      | MN |                     | DHCP  |   |Server|
      |    |                     | relay |   |      |
      +----+                     +-------+   +------+
        |            RRQ             |          |
        |--------------------------->|          |
        |            RRP             |          |
        |<---------------------------|          |
        |             1              |          |
        |--------------------------->|          |
        |                            |    2     |
        |                            |--------->|
        |                            |          |
        |                            |    3     |
        |                            |<---------|
        |             4              |          |
        |<---------------------------|          |


        Figure 2: Message sequence for host configuration in Co-CoA

   Figure 2 shows the message sequence for host configuration in Co-CoA.

   (1) After the mobile node successfully registered to the home agent
   based on Registration Request(RRQ) and Registration Response(RRP)
   message, it sends a DHCPINFORM message to request specific
   configuration parameters by including the 'parameter request list'
   option from home network.  The mobile node generates and records a
   random transaction identifier and inserts that identifier into the
   'xid' field.  The mobile node places its own home address in the
   'ciaddr' field.

   The mobile node will send DHCPINFORM message to the limited (all 1s)
   broadcast address.  DHCPINFORM messages MUST be directed to the 'DHCP
   server' UDP port.

   The mobile node will encapsulate this DHCPINFORM broadcast message
   with IP in IP tunnel and send to the home agent, DHCPINFORM Packet
   format sent by the mobile node is shown below:











Deng                     Expires January 3, 2009                [Page 5]


Internet-Draft            DHCP MN Configuration                July 2008


     IP fields (encapsulating header):
      Source Address       =  mobile node's home address
      Destination Address  =  home agent's address
      Protocol field: 4 (IP in IP)
     IP fields (original header):
      Source Address       =  mobile node's home address
      Destination Address  =  broadcast address
     UDP Src Port: bootpc(68), Dst Port: bootps(67)
     Bootstrap Protocol:
      field:
       op     = BOOTREQUEST
       htype  = Ethernet or (From "Assigned Numbers" RFC)
       hlen   = 6 or (Hardware address length in octets)
       hops   = 0
       xid    = selected by client
       secs   = 0
       flags  = 0
       ciaddr = mobile node's home address
       yiaddr = 0
       siaddr = 0
       giaddr = 0
       chaddr = mobile node's MAC address
      options:
       option 53: DHCP Message Type = DHCPINFORM
       option 61: Client Identifier = mobile node's MAC address
       option 55: Parameter request List (Domain Name Server,... et al.)

   (2) Since the home agent acts as the DHCP relay agent, after
   receiving a unicast tunnel message, it detunneled the unicast
   encapsulated header, and should look at the the 'giaddr' field of
   DHCPINFORM message.  If zero, it should plug its own IP address into
   this field.  It may also use the 'hops' field to optionally control
   how far the packet is reforwarded.  Hops should be incremented on
   each forwarding.

   DHCPINFORM Packet format forwarded by the home agent:

      IP fields:
        Source Address       =  home agent's address
        Destination Address  =  DHCP server's address
      UDP Src Port: bootps(67), Dst Port: bootps(67)
      Bootstrap Protocol:
       field:
        giaddr = home agent's address

   (3) DHCP server receiving a DHCPINFORM message construct a DHCPACK
   message with any home configuration parameters appropriate for the
   mobile node according to Section 3.4 of [RFC2131] .  The DHCP server



Deng                     Expires January 3, 2009                [Page 6]


Internet-Draft            DHCP MN Configuration                July 2008


   SHOULD unicast the DHCPACK reply to the address given in the 'giaddr'
   field of the DHCPINFORM message.

   DHCPACK Packet format sent by the DHCP Server:

    IP fields:
      Source Address       =  DHCP server's address
      Destination Address  =  home agent's address
                              (from 'giaddr' of DHCPINFORM)
    UDP Src Port: bootps(67), Dst Port: bootps(67)
     Bootstrap Protocol:
      field:
       op     = BOOTREPLY
       htype  = Ethernet or (From "Assigned Numbers" RFC)
       hlen   = 6 or (Hardware address length in octets)
       hops   = 0
       xid    = same as "xid" field of DHCPINFORM message
       secs   = 0
       flags  = 0
       ciaddr = mobile node's home address (from 'ciaddr' of DHCPINFORM)
       yiaddr = 0
       siaddr = 0
       giaddr = home agent's address (from 'giaddr' of DHCPINFORM)
       chaddr = mobile node's MAC address (from 'chaddr' of DHCPINFORM)
      options:
       option 53: DHCP Message Type = DHCPACK
       option 61: Server Identifier = DHCP server's MAC address
       option  6: Domain Name Server
       all other options: if needed

   (4) The home agent intercepting a unicast DHCPACK message will
   tunnels this datagram to the mobile node's currently registered
   care-of address.

   DHCPACK Packet format forwarded by the home agent:

      IP fields (encapsulating header):
        Source Address       =  home agent's address
        Destination Address  =  mobile node's care-of-address
        Protocol field: 4 (IP in IP)
      IP fields (original header):
        Source Address       =  DHCP server's address
        Destination Address  =  mobile node's home address
      UDP Src Port: bootps(67), Dst Port: bootpc(68)
       Bootstrap Protocol

   Once a DHCPACK message with an 'xid' field matching that in the
   mobile node's DHCPINFORM message arrives from any server, the mobile



Deng                     Expires January 3, 2009                [Page 7]


Internet-Draft            DHCP MN Configuration                July 2008


   node's configuration process is finished.

   If the mobile node does not receive a DHCPACK within a reasonable
   period of time (60 seconds or 4 tries if using timeout suggested in
   section 4.1), then it SHOULD display a message informing the user of
   the problem, and then SHOULD begin network processing using suitable
   defaults as per Appendix A of [RFC2131].

2.2.  MIP4 FA CoA Case

   If the 'D' bit was not set in the mobile node's Registration Request
   message, and code field of the received registration reply indicate
   successly registered.  This means that the mobile node is using a
   foreign agent care-of address.

   Reverse tunneling [RFC3024] in Mobile IP has mandate that a mobile
   node using a foreign agent care-of address MUST use the encapsulating
   delivery style.  So the operation of DHCPINFORM broadcast message to
   the home network in this case should follow the encapsulating
   delivery style.

                     +-----+    +-------+
                     | HA/ |____| Home  |
                     |DHCP |----| DHCP  |
                     |Relay|    | Server|
                     +-----+    +-------+
                       ||
                       ||   Home Network
       ----------------||--------------------
                       ||   Visiting Network
                       ||
                     +----+
         +----+______|    |
         | MN |------| FA |
         +----+      |    |
                     +----+

        Figure 3: Home network configuration in the case of FA-CoA













Deng                     Expires January 3, 2009                [Page 8]


Internet-Draft            DHCP MN Configuration                July 2008


      +----+        +-----+      +-------+   +------+
      |    |        |     |      |  HA   |   |DHCP  |
      | MN |        | FA  |      | DHCP  |   |Server|
      |    |        |     |      | relay |   |      |
      +----+        +-----+      +-------+   +------+
        |               |             |          |
        |            RRQ              |          |
        |---------------------------->|          |
        |            RRP              |          |
        |<----------------------------|          |
        |       1       |             |          |
        |-------------->|             |          |
        |               |      2      |          |
        |               |------------>|          |
        |               |             |    3     |
        |               |             |--------->|
        |               |             |    4     |
        |               |             |<---------|
        |               |      5      |          |
        |               |<------------|          |
        |       6       |             |          |
        |<--------------|             |          |

        Figure 4: Message sequence for host configuration in FA-CoA

   Figure 4 shows the message sequence for host configuration in Co-CoA.

   (1) After the mobile node successfully registered to the home agent
   based on Registration Request(RRQ) and Registration Response(RRP)
   messages, it sends a DHCPINFORM message to request specific
   configuration parameters by including the 'parameter request list'
   option from home network.  The mobile node generates and records a
   random transaction identifier and inserts that identifier into the
   'xid' field.  The mobile node places its own home address in the
   'ciaddr' field.

   The mobile node send DHCPINFORM the message to the limited (all 1s)
   broadcast address.  DHCPINFORM messages MUST be directed to the 'DHCP
   server' UDP port.

   The mobile node will encapsulate this DHCPINFORM broadcast message
   with IP in IP tunnel and send to the foriegn agent, DHCPINFORM Packet
   format sent by the mobile node is shown below:








Deng                     Expires January 3, 2009                [Page 9]


Internet-Draft            DHCP MN Configuration                July 2008


    IP fields (encapsulating header):
      Source Address       =  mobile node's home address
      Destination Address  =  foreign agent's address
      Protocol field: 4 (IP in IP)
    IP fields (original header):
      Source Address       =  mobile node's home address
      Destination Address  =  broadcast address
    UDP Src Port: bootpc(68), Dst Port: bootps(67)
     Bootstrap Protocol:
      field:
       op     = BOOTREQUEST
       htype  = Ethernet or (From "Assigned Numbers" RFC)
       hlen   = 6 or (Hardware address length in octets)
       hops   = 0
       xid    = selected by client
       secs   = 0
       flags  = 0
       ciaddr = mobile node's home address
       yiaddr = 0
       siaddr = 0
       giaddr = 0
       chaddr = mobile node's MAC address
      options:
       option 53: DHCP Message Type = DHCPINFORM
       option 61: Client Identifier = mobile node's MAC address
       option 55: Parameter request List (Domain Name Server,... et al.)

   (2) Packet format forwarded by the foreign agent (Encapsulating
   Delivery Style):

      IP fields (encapsulating header):
        Source Address       =  foreign agent's care-of-address
        Destination Address  =  home agent's address
        Protocol field: 4 (IP in IP)
      IP fields (original header):
        Source Address       =  mobile node's home address
        Destination Address  =  broadcast address
      UDP Src Port: bootpc(68), Dst Port: bootps(67)
       Bootstrap Protocol

   Since the home agent acts as the DHCP relay agent, after receiving a
   unicast tunnel message, it detunneled the unicast encapsulated
   header, and should look at the the 'giaddr' field of DHCPINFORM
   message.  If zero, it should plug its own IP address into this field.
   It may also use the 'hops' field to optionally control how far the
   packet is reforwarded.  Hops should be incremented on each
   forwarding.




Deng                     Expires January 3, 2009               [Page 10]


Internet-Draft            DHCP MN Configuration                July 2008


   (3) DHCPINFORM Packet format forwarded by the home agent:

      IP fields:
        Source Address       =  home agent's address
        Destination Address  =  DHCP server's address
      UDP Src Port: bootps(67), Dst Port: bootps(67)
      Bootstrap Protocol:
       field:
        giaddr = home agent's address

   (4) DHCP server receiving a DHCPINFORM message construct a DHCPACK
   message with any home configuration parameters appropriate for the
   mobile node according to Section 3.4 of [RFC2131] .  The DHCP server
   SHOULD unicast the DHCPACK reply to the address given in the 'giaddr'
   field of the DHCPINFORM message.

   DHCPACK Packet format sent by the DHCP Server:

    IP fields:
      Source Address       =  DHCP server's address
      Destination Address  =  home agent's address
                              (from 'giaddr' of DHCPINFORM)
    UDP Src Port: bootps(67), Dst Port: bootps(67)
     Bootstrap Protocol:
      field:
       op     = BOOTREPLY
       htype  = Ethernet or (From "Assigned Numbers" RFC)
       hlen   = 6 or (Hardware address length in octets)
       hops   = 0
       xid    = same as "xid" field of DHCPINFORM message
       secs   = 0
       flags  = 0
       ciaddr = mobile node's home address (from 'ciaddr' of DHCPINFORM)
       yiaddr = 0
       siaddr = 0
       giaddr = home agent's address (from 'giaddr' of DHCPINFORM)
       chaddr = mobile node's MAC address (from 'chaddr' of DHCPINFORM)
      options:
       option 53: DHCP Message Type = DHCPACK
       option 61: Server Identifier = DHCP server's MAC address
       option  6: Domain Name Server
       all other options: if needed

   (5) The home agent intercepting a unicast DHCPACK message will
   tunnels this datagram to the foreign agent care-of address.

   DHCPACK Packet format forwarded by the home agent:




Deng                     Expires January 3, 2009               [Page 11]


Internet-Draft            DHCP MN Configuration                July 2008


      IP fields (encapsulating header):
        Source Address       =  home agent's address
        Destination Address  =  foreign agent's care-of-address
        Protocol field: 4 (IP in IP)
      IP fields (original header):
        Source Address       =  DHCP server's address
        Destination Address  =  mobile node's home address
      UDP Src Port: bootps(67), Dst Port: bootpc(68)
       Bootstrap Protocol

   (6) DHCPACK Packet format forwarded by the foreign agent:

      IP fields (encapsulating header):
        Source Address       =  foreign agent's address
        Destination Address  =  mobile node's home address
        Protocol field: 4 (IP in IP)
      IP fields (original header):
        Source Address       =  DHCP server's address
        Destination Address  =  mobile node's home address
      UDP Src Port: bootps(67), Dst Port: bootpc(68)
       Bootstrap Protocol

   Once a DHCPACK message with an 'xid' field matching that in the
   mobile node's DHCPINFORM message arrives from any server, the mobile
   node's configuration process is finished.

   If the mobile node does not receive a DHCPACK within a reasonable
   period of time (60 seconds or 4 tries if using timeout suggested in
   section 4.1), then it SHOULD display a message informing the user of
   the problem, and then SHOULD begin network processing using suitable
   defaults as per Appendix A of [RFC2131].




















Deng                     Expires January 3, 2009               [Page 12]


Internet-Draft            DHCP MN Configuration                July 2008


3.  Home DHCP server's address known

   If a mobile node has obtained a DHCP server address through some
   other means (how to obtain is out scope of this document), after
   registration process, it may send a DHCPINFORM unicast message to
   obtain other local configuration parameters.

   According to Section 1.7 of [RFC3344], in the reverse direction,
   datagrams sent by the mobile node are generally delivered to their
   destination using standard IP routing mechanisms, not necessarily
   passing through the home agent.

      +----+        +-----+      +-------+   +------+
      |    |        |     |      |       |   |DHCP  |
      | MN |        | FA  |      |  HA   |   |Server|
      |    |        |     |      |       |   |      |
      +----+        +-----+      +-------+   +------+
        |               |             |          |
        |            RRQ              |          |
        |---------------------------->|          |
        |            RRP              |          |
        |<----------------------------|          |
        |       1       |             |          |
        |--------------------------------------->|
        |               |             |    2     |
        |               |             |<---------|
        |               |      3      |          |
        |<----------------------------|          |
        |               |      3      |          |
        |               |<------------|          |
        |       4       |             |          |
        |<--------------|             |          |

        Figure 5: Message sequence for Known DHCP server's address

   Figure 5 shows the message sequence for host configuration with known
   DHCP server's address.

   (1) After the mobile node successfully registered to the home agent
   based on Registration Request(RRQ) and Registration Response(RRP)
   message, it then unicasts the DHCPINFORM to the DHCP server based on
   standard IP routing mechanisms whatever it is co-colated care-of
   address or foreign agent care-of address.

   DHCPINFORM Packet format sent by the mobile node is shown below:






Deng                     Expires January 3, 2009               [Page 13]


Internet-Draft            DHCP MN Configuration                July 2008


    IP fields:
      Source Address       =  mobile node's home address
      Destination Address  =  DHCP server's address
    UDP Src Port: bootpc(68), Dst Port: bootps(67)
     Bootstrap Protocol:
      field:
       op     = BOOTREQUEST
       htype  = Ethernet or (From "Assigned Numbers" RFC)
       hlen   = 6 or (Hardware address length in octets)
       hops   = 0
       xid    = selected by client
       secs   = 0
       flags  = 0
       ciaddr = mobile node's home address
       yiaddr = 0
       siaddr = 0
       giaddr = 0
       chaddr = mobile node's MAC address
      options:
       option 53: DHCP Message Type = DHCPINFORM
       option 61: Client Identifier = mobile node's MAC address
       option 55: Parameter request List (Domain Name Server,... et al.)

   (2) DHCP server receiving a DHCPINFORM message construct a DHCPACK
   message with any home configuration parameters appropriate for the
   mobile node according to Section 3.4 of [RFC2131] .  If the 'giaddr'
   field is zero and the 'ciaddr' field is nonzero, then the DHCP server
   SHOULD unicast the DHCPACK reply to the address given in the 'ciaddr'
   field of the DHCPINFORM message.

   DHCPACK Packet format sent by the DHCP Server:




















Deng                     Expires January 3, 2009               [Page 14]


Internet-Draft            DHCP MN Configuration                July 2008


    IP fields:
      Source Address       =  DHCP server's address
      Destination Address  =  mobile node's home address
                              (from 'ciaddr' of DHCPINFORM)
    UDP Src Port: bootps(67), Dst Port: bootpc(68)
     Bootstrap Protocol:
      field:
       op     = BOOTREPLY
       htype  = Ethernet or (From "Assigned Numbers" RFC)
       hlen   = 6 or (Hardware address length in octets)
       hops   = 0
       xid    = same as "xid" field of DHCPINFORM message
       secs   = 0
       flags  = 0
       ciaddr = mobile node's home address (from 'ciaddr' of DHCPINFORM)
       yiaddr = 0
       siaddr = 0
       giaddr = 0
       chaddr = mobile node's MAC address (from 'chaddr' of DHCPINFORM)
      options:
       option 53: DHCP Message Type = DHCPACK
       option 61: Server Identifier = DHCP server's MAC address
       option  6: Domain Name Server
       all other options: if needed

   (3,4) The home agent intercepting a unicast DHCPACK message will
   tunnels this datagram to the mobile node's home address based on
   standard mobile IP process.

   According to Sections 5.5 and 5.6 of the Mobile IP specification
   [RFC3344], the mobile node may create a tunnel to its home agent.
   Then, datagrams destined for DHCP server will appear to emanate from
   the home network.  This kind of process could be refered to section 2
   of this document.

















Deng                     Expires January 3, 2009               [Page 15]


Internet-Draft            DHCP MN Configuration                July 2008


4.  Security Considerations

   This document just analyse the process of DHCPINFORM support in
   mobile IP environment, it operates in the security constraints and
   requirements of [RFC2131] and [RFC3344].














































Deng                     Expires January 3, 2009               [Page 16]


Internet-Draft            DHCP MN Configuration                July 2008


5.  IANA Consideration

   This document makes no requests to IANA.
















































Deng                     Expires January 3, 2009               [Page 17]


Internet-Draft            DHCP MN Configuration                July 2008


6.  Acknowledgments

   The author thanks the discussion from Kent Leung, Alexandru Petrescu,
   Charles E. Perkins, Jari Arkko, Vijay Devarapalli, Hans Sjostrand,
   Peng Yang and et al. in the development of this document.

   The efforts of McCann Peter and Henrik Levkowetz in reviewing this
   document are gratefully acknowledged.











































Deng                     Expires January 3, 2009               [Page 18]


Internet-Draft            DHCP MN Configuration                July 2008


7.  Conclusion

   This document verified that mobile node could get home network
   configuration based on DHCPINFORM without any revision of basic
   mobile IP specification.














































Deng                     Expires January 3, 2009               [Page 19]


Internet-Draft            DHCP MN Configuration                July 2008


8.  Normative References

   [RFC0951]  Croft, B. and J. Gilmore, "Bootstrap Protocol", RFC 951,
              September 1985.

   [RFC1700]  Reynolds, J. and J. Postel, "Assigned Numbers", RFC 1700,
              October 1994.

   [RFC1701]  Hanks, S., Li, T., Farinacci, D., and P. Traina, "Generic
              Routing Encapsulation (GRE)", RFC 1701, October 1994.

   [RFC2003]  Perkins, C., "IP Encapsulation within IP", RFC 2003,
              October 1996.

   [RFC2004]  Perkins, C., "Minimal Encapsulation within IP", RFC 2004,
              October 1996.

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

   [RFC3024]  Montenegro, G., "Reverse Tunneling for Mobile IP,
              revised", RFC 3024, January 2001.

   [RFC3344]  Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
              August 2002.


























Deng                     Expires January 3, 2009               [Page 20]


Internet-Draft            DHCP MN Configuration                July 2008


Author's Address

   Hui Deng
   China Mobile
   53A,Xibianmennei Ave.,
   Xuanwu District,
   Beijing  100053
   China

   Email: denghui02@gmail.com









































Deng                     Expires January 3, 2009               [Page 21]


Internet-Draft            DHCP MN Configuration                July 2008


Full Copyright Statement

   Copyright (C) The IETF Trust (2008).

   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, THE IETF TRUST 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.











Deng                     Expires January 3, 2009               [Page 22]