One document matched: draft-ietf-mipshop-mos-dhcp-options-05.txt

Differences from draft-ietf-mipshop-mos-dhcp-options-04.txt


MIPSHOP WG                                                  Gabor Bajko 
Internet Draft                                                    Nokia 
Intended Status: Proposed Standard                            Subir Das 
Expires: March 07, 2009                                       Telcordia 
                                                     September 08, 2008 
    
    
  Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Options for 
                    Mobility Server (MoS) discovery 
                    draft-ietf-mipshop-mos-dhcp-options-05 
 
 
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 
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   The list of Internet-Draft Shadow Directories can be accessed at 
   http://www.ietf.org/shadow.html. 
    
   This Internet-Draft will expire on October 19, 2008. 
    
Copyright Notice 
    
   Copyright (C) The IETF Trust (2008). 
 
Abstract 
    
   This document defines a number of Dynamic Host Configuration 
   Protocol (DHCP-for-IPv4 and DHCP-for-IPv6) options that contain a 
   list of domain names or IP addresses that can be mapped to servers 
   providing IEEE 802.21 type of Mobility Services [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].  
    
Conventions used in this document 
    
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   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. 
    
Terminology and abbreviations used in this document 
    
   Mobility Services: comprises of a set of different services provided 
   by the network to mobile nodes to facilitate handover preparation 
   and handover decision. 
    
   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 Content 
    
   1. Introduction .................................................2 
   2. DHCPv4 Options for MoS Discovery..............................3     
        2.1 Domain Name List........................................5 
        2.2 IPv4 Address List.......................................6 
   3. DHCPv6 Options for MoS Discovery..............................6 
        3.1 IPv6 MoS Identifier Option..............................6  
        3.2 IPv6 MoS Information Option.............................7 
   4. Option Usage..................................................9 
        4.1 Usage of DHCPv4 Options for MoS Discovery...............9 
        4.2 Usage of DHCPv6 Options for MoS Discovery..............10 
   5. Security Considerations .....................................11 
   6. IANA Considerations .........................................11 
   7. Acknowledgements ............................................12 
   8. References ..................................................12 
       8.1 Normative References ...................................12
       8.2 Informative References .................................12 
   Author's Addresses .............................................13 
   Intellectual Property and Copyright Statements .................13

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 the heterogeneous 
   networks and perform seamless handover across these networks. 



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     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 a new dhcpv4 option called MoS option, which 
   allows the MN to locate a Mobility Server which hosts the desired 
   service type (i.e. IS, ES or CS)as defined in [IEEE802.21]. The MoS 
   information type defines sub-options for different services. The 
   document also defines  DHCPv6 options that allow the MN to 
   discover Mobility Servers hosting MIH services in different 
   deployment scenarios. Apart from manual configuration, this is one 
   of the possible solutions for locating a server providing Mobility 
   Services.  
    
2. DHCPv4 Option for MoS Discovery 
    
   This section describes the MoS option for DHCPv4.
   The MoS 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-IPv4-MoS (TBD) - 2 bytes  
    
            Length 
    
                 2 bytes 

            Sub-options 
    
               A series of DHCPv4 sub-options. 

   When the total length of a MoS option exceeds 255 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 Type followed by a length 
   and a `enc` field. The value of the length octet does not include 
   itself or the option code. There are two types of encodings,  
   specified by the encoding byte ('enc') that follows the code byte. 
   If the encoding byte has the value 0, it is followed by a list of 
   domain names, as described below (Section 2.1). If the encoding byte 
   has the value 1, it is followed by one or more IPv4 addresses 
   (Section 2.2). 

   All implementations MUST support both encodings. A DHCP server MUST 
   NOT mix the two encodings in the same DHCP message, even if it sends 
   two different instances of the same option. Attempts to do so would 
   result in incorrect client behavior as DHCP processing rules call 
   for the concatenation of multiple instances of an option into a 
   single option prior to processing the option [RFC3396].

   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 Type  |         length                |    enc        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |              FQDN or IP Address                               | 
      .                                                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The sub-option Types are summarized below.
      +--------------+---------------+
      |  Sub-opt     | Service       |                               
      |   Type*      | Name          |                                            
      +==============+===============+
      |    1         |   IS          |
      +--------------+---------------+
      |    2         |   ES          | 
      +--------------+---------------+


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      +--------------+---------------+
      |    3         |  IS and ES    | 
      +--------------+---------------+
      |    4         |   CS          | 
      +--------------+---------------+
      |    5         |  IS and CS    |
      +--------------+---------------+
      |    6         |  ES and CS    |
      +--------------+---------------+
      |    7         | IS, CS and ES |
      +--------------+---------------+

*Note: The values `0` '8' to '255' are reserved and MUST NOT be used.  
  
    2.1 Domain Name List 
    
   If the 'enc' byte has a value of 0, the encoding byte is followed by 
   a sequence of labels, encoded according to Section 3.1 of [RFC1035], 
   quoted below: 
    
        Domain names in messages are expressed in terms of a sequence 
        of labels. Each label is represented as a one octet length 
        field followed by that number of octets.  Since every domain 
        name ends with the null label of the root, a domain name is 
        terminated by a length byte of zero. The high order two bits of 
        every length octet must be zero, and the remaining six bits of 
        the length field limits the label to 63 octets or less. To 
        simplify implementations, the total length of a domain name 
        (i.e., label octets and label length octets) is restricted to 
        255 octets or less. 
    
   [RFC1035] encoding was chosen to accommodate future international-
   lized domain name mechanisms. The minimum length for this encoding 
   is 3. 
    
   The option MAY contain multiple domain names, but these SHOULD refer 
   to different NAPTR records, rather than different A records. 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. 
    
   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 sub-option for this encoding has the following format: 




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           Type Len enc DNS name of MoS server 
         +-----+---+---+-----+-----+-----+-----+-----+-- 
         |1..7 | n | 0 |  s1 |  s2 |  s3 |  s4 | s5  |  ... 
         +-----+---+---+-----+-----+-----+-----+-----+-- 
 
   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..7|27 | 0 | 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 | 
   +---+---+---+---+---+---+---+---+---+---+---+---+---+ 

    
2.2 IPv4 Address List 
    
   If the 'enc' byte has a value of 1, the encoding byte 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 5, and the length MUST be a multiple of 4 plus 
   one. The sub-option for this encoding has the following format: 
    
           Code Len enc IPv4 Address 1 IPv4 Address 2 
         +-----+---+---+-----+----+---+----+----+-- 
         |1..7 | n | 1 | a1  | a2 |a3 | a4 | a1 |  ... 
         +-----+---+---+-----+----+---+----+----+-- 
    
 
3.  DHCPv6 Options for MoS discovery 
    
   This section introduces new DHCPv6 options used for MoS discovery. 
    
   Whether the MN receives an MoS address from local or home network 
   will depend on the actual network deployment [MSFD]. 
    
   
3.1 IPv6 MoS Identifier Option 
 
   This option is included in the Information-request message and used 
   to request the address of a specific (e.g., IS, ES, CS or any 
   combination) MoS-type from a DHCP server. 
    
       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              | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |   MoS-type    |                Reserved                       | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

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    Option Code 
    
               OPTION-IPv6-MoS (TBD) - 2 bytes  
  
               Length 
   
                   2 bytes 

               MoS-Type* 

                   1 byte

                 The type of Mobility Services the MN is looking for, 
               i.e., IS, ES or CS or a combination of these: 

                    +--------------+-------------- +
                    |  MoS-type    | MoS Name      |                               
                    |   value      |               |                                            
                    +==============+===============+
                    |    1         |   IS          |
                    +--------------+---------------+
                    |    2         |   ES          |
                    +--------------+---------------+
                    |    3         |  IS and ES    | 
                    +--------------+---------------+
                    |    4         |   CS          | 
                    +--------------+---------------+
                    |    5         |  IS and CS    |
                    +--------------+---------------+
                    |    6         |  ES and CS    |
                    +--------------+---------------+
                    |    7         | IS, CS and ES |
                    +--------------+---------------+ 
     *Note: The values '0', '8' to '255' are reserved and MUST NOT be 
     used. 
      
 
3.2 IPv6 MoS Information Option 
    
   This option is included in the Reply message and used to carry MoS 
   information to the mobile node in the form of one or more of MoS IP 
   address(es) or MoS FQDN(s). 

       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-options                          . 
      .                                                               . 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
            
 
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           Option Code 
               OPTION-IPv6-MoSINF (TBD)- 2 bytes  
    
            Length 
    
               The length of sub-options 
    
            sub-options 
    
               A series of MoS  Information sub-options. 

    
3.2.1 MoS Information Sub-option 
    
   This sub-option carries the assigned MoS information to the DHCP 
   client. 
      
       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                    |     MoS Type  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                                                               | 
      .                     MoS Information                           . 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

            Sub-opt Code 
    
               An 8-bit unsigned integer for the type of the following 
               MoS Information field. Possible values are: 
    
                   1    MoS IP address 
    
                   2    MoS FQDN 
    
            Length 
    
               1 + length of MoS Information field. 
             
              MoS-Type* 
                 1 byte

                 The type of Mobility Services the MN is looking for, 
               i.e., IS, ES or CS or a combination of these: 

                    +--------------+-------------- +
                    |  MoS Type    | MoS Name      |                               
                    |   value      |               |                                            
                    +==============+===============+
                    |    1         |   IS          |
                    +--------------+---------------+
                    |    2         |   ES          |
                    +--------------+---------------+

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                    +--------------+---------------+
                    |    3         |  IS and ES    | 
                    +--------------+---------------+
                    |    4         |   CS          | 
                    +--------------+---------------+
                    |    5         |  IS and CS    |
                    +--------------+---------------+
                    |    6         |  ES and CS    |
                    +--------------+---------------+
                    |    7         | IS, CS and ES |
                    +--------------+---------------+ 

   *Note: The values '0', '8' to '255' are reserved and MUST NOT be 
     used. 

              MoS Information 
    
               An MoS IP address or MoS FQDN to be provided to a mobile  
               node as indicated in the sub-opt-code. 
    
   When the sub-opt-code is set to 1, the MoS Information field MUST 
   contain the 128-bit IPv6 address of the MoS. 
    
   When the sub-opt-code is set to 2, the MoS Information field MUST 
   contain the FQDN of the MoS as described in Section 8 of [RFC3315]. 
    
      
4. Option Usage 
    
4.1 Usage of DHCPv4 Options for MoS Discovery 
     
   The requesting and sending of the proposed DHCPv4 option follow the 
   rules for DHCP options in [RFC2131]. 
     
4.1.1 Mobile Node behavior 
    
   The mobile node may perform the MoS information discovery procedure 
   either during initial association with a network or when the 
   mobility service is required. It may also try to perform the MoS
   information 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 acquire the MoS information, the mobile node MUST send 
   either a DHCPDISCOVER or DHCPINFORM message to a subnet broadcast or 
   a unicast server address, respectively. In this message the mobile 
   node (DHCP client) MUST include the sub-opt Type for the MoS 
   Discovery in the sub-options field. 
    





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4.1.2 DHCP Server behavior 
    
   When the DHCP server receives the DHCPDISCOVER or DHCPINFORM message 
   with the MoS Discovery option in the options field, the DHCP server 
   MUST follow the [RFC2131] logic to construct either a DHCPOFFER or 
   DHCPACK message including the MoS Discovery option. The reply 
   message may contain the IP address or the FQDN of the MoS Server. 

   The DHCP server MUST always construct the response according to 
   the Sub-opt Type requested by the DHCP client.

   In case that the server cannot find any MoS information for a
   specific MoS sub-opt Type, it MUST return the MoS option with a
   sub-option by setting the sub-opt Type to the requested 
   sub-opt Type and the length of the sub-option to 1. 
   

    
4.2 DHCPv6 Options for MoS discovery 
    
   The requesting and sending of the proposed DHCPv6 options follow the 
   rules for DHCP options in [RFC3315]. 
    
4.2.1 Mobile node behavior 
    
   The mobile node may perform the MoS information discovery procedure 
   either during initial association with a network or when the 
   mobility service is required. It may also try to perform the MoS 
   information 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 acquire the MoS address, the mobile node MUST send an 
   Information-request message to the All_DHCP_Servers 
   multicast address. In this message the mobile node (DHCP client) 
   MUST include the Option Code for the MoS Discovery option in the 
   option_code. 



4.2.2 DHCP Server behavior 
    
   When the DHCP Server receives the Information-request message the 
   DHCP server MUST follow the following logic to construct a Reply 
   message with the MoS Information option.


   If the DHCP server has the requested MoS information, it MUST 
   include the information in the MoS Information option. The server 
   may provide the matching information from the preconfigured 
   information available locally.  


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   The DHCP server MUST always construct the response
   according to the MoS Type requested by the DHCP client.

   In case that the server cannot find any MoS information for a 
   specific MoS type, it MUST return the MoS Information option with 
   a sub-option by setting the MoS type to the requested MoS Type 
   and the length of the sub-option to 4.

    
5. 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.  

   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. 
    
6. IANA Considerations 

  This document defines one new DHCPv4 option as described in section 
  2. 

   MoS Option for DHCPv4 (OPTION-IPv4-MoS)                 TBD
  
   This document creates a new registry for the Sub-Option field in the
   MoS DHCPv4 option called the "MoS Service Type".
      IS                       1
      ES                       2
      IS and ES                3  
      CS                       4
      IS and CS                5
      ES and CS                6
      IS, CS and ES            7

  The values '0', '8' to '255' are reserved and MUST NOT be used. New
  values can be allocated by Standards Action or IESG approval.

  This document also defines new DHCPv6 options as described in 
  sections 3.1 and 3.2

     IPv6-MoS (IPv6 MoS Identifier Option)                 TBD
     IPv6-MoSINF (IPv6 MoS Information Option)             TBD
          	
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   This document creates a new registry for the "MoS Type" field in 
   the IPv6 MoS Information Sub-option (section 3.2).

        IS                       1
        ES                       2
        IS and ES                3
        CS                       4
        IS and CS                5
        ES and CS                6
        IS, CS and ES            7

  The values '0', '8' to '255' are reserved and MUST NOT be used. New
  Values can be allocated by Standards Action or IESG approval.
    
  
7. Acknowledgements 
    
   Authors would like to acknowledge the following individuals for 
   their valuable comments. 
   Vijay Devarapalli, Telemaco Melia, and Yoshihiro Ohba 


8. References

    8.1 Normative References 
    
   [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 
      2131, March 1997. 
    
   [RFC1035] Mockapetris, P., "Domain names - implementation and 
      specification", STD 13, RFC 1035, November 1987. 
     
  [RFC3396] Lemon, T. and S. Cheshire, "Encoding Long DHCP Options", 
      RFC3396, November 2002.    
   
   [RFC3118] Authentication for DHCP Messages, Droms et al, June 2001 
   
   [RFC3315] Dynamic Host Configuration Protocol for IPv6 (DHCPv6), 
      Droms et al, July 2003 


   8.2 Informative References 
    
   [IEEE802.21] IEEE 802.21 Standard for Local and Metropolitan Area 
      Networks: Media Independent Handover Services 
    
   [MoS-DNS] Bajko, G., "Locating Mobility Servers",
      draft-ietf-mipshop-mos-dns-discovery, (Work in Progress), 
      May 2008. 

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


    
 Authors' Addresses 
    
   Gabor Bajko 
   Nokia 
   e-mail: gabor.bajko@nokia.com 
     
   Subir Das 
   Telcordia Technologies Inc.
   e-mail: subir@research.telcordia.com 
    

  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. 


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   The IETF invites any interested party to bring to its attention any 
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   ipr@ietf.org. 
    
    
Acknowledgment 
    
   Funding for the RFC Editor function is provided by the IETF 
   Administrative Support Activity (IASA). 









































G. Bajko & S. Das          Expires 03/07/08                 [Page 14]


PAFTECH AB 2003-20262026-04-24 06:06:16