Diameter Maintenance and                                     J. Korhonen
Extensions (DIME)                                            TeliaSonera
Internet-Draft                                              J. Bournelle
Intended status: Standards Track                             Orange Labs
Expires: August 17, 2008                                   H. Tschofenig
                                                  Nokia Siemens Networks
                                                              C. Perkins

                                                            K. Chowdhury
                                                        Starent Networks
                                                       February 14, 2008


  Diameter Mobile IPv6: Support for Network Access Server to Diameter
                           Server Interaction
                 draft-ietf-dime-mip6-integrated-08.txt

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Copyright Notice

   Copyright (C) The IETF Trust (2008).






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Abstract

   A Mobile IPv6 node requires a home agent address, a home address, and
   a security association with its home agent before it can start
   utilizing Mobile IPv6.  RFC 3775 requires that some or all of these
   parameters are statically configured.  Mobile IPv6 bootstrapping work
   aims to make this information dynamically available to the Mobile
   Node.  An important aspect of the Mobile IPv6 bootstrapping solution
   is to support interworking with existing authentication,
   authorization and accounting infrastructure.  This document describes
   the MIPv6 bootstrapping using the Diameter Network Access Server
   (NAS) to home Authentication, Authorization and Accounting server
   (HAAA) interface.






































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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology and Abbreviations  . . . . . . . . . . . . . . . .  4
   3.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
   4.  Commands, AVPs and Advertising Application Support . . . . . .  7
     4.1.  Advertising Application Support  . . . . . . . . . . . . .  7
     4.2.  Command Codes  . . . . . . . . . . . . . . . . . . . . . .  7
     4.3.  Diameter-EAP-Request (DER) . . . . . . . . . . . . . . . .  8
     4.4.  Diameter-EAP-Answer (DEA)  . . . . . . . . . . . . . . . .  8
     4.5.  AA-Request (AAR) . . . . . . . . . . . . . . . . . . . . .  9
     4.6.  AA-Answer (AAA)  . . . . . . . . . . . . . . . . . . . . .  9
     4.7.  Attribute Value Pair Definitions . . . . . . . . . . . . . 10
       4.7.1.  MIP6-Agent-Info  . . . . . . . . . . . . . . . . . . . 10
       4.7.2.  MIP-Home-Agent-Address AVP . . . . . . . . . . . . . . 11
       4.7.3.  MIP-Home-Agent-Host AVP  . . . . . . . . . . . . . . . 11
       4.7.4.  MIP6-Home-Link-Prefix AVP  . . . . . . . . . . . . . . 11
       4.7.5.  MIP6-Feature-Vector AVP  . . . . . . . . . . . . . . . 11
   5.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     5.1.  Home Agent Assignment by the NAS . . . . . . . . . . . . . 13
     5.2.  Home Agent Assignment by the Diameter Server . . . . . . . 14
     5.3.  Home Agent Assignment by NAS or Diameter Server  . . . . . 14
   6.  AVP Occurrence Tables  . . . . . . . . . . . . . . . . . . . . 16
     6.1.  AAR, AAA, DER and DEA Commands AVP Table . . . . . . . . . 16
   7.  MIPv6 Bootstrapping NAS to HAAA Interface AVPs . . . . . . . . 16
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 17
     8.1.  Registration of new AVPs . . . . . . . . . . . . . . . . . 17
     8.2.  New Registry: Mobility Capability  . . . . . . . . . . . . 17
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 18
   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 18
     11.2. Informative References . . . . . . . . . . . . . . . . . . 19
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
   Intellectual Property and Copyright Statements . . . . . . . . . . 21
















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1.  Introduction

   The Mobile IPv6 (MIPv6) specification [1] requires a Mobile Node (MN)
   to perform registration with a home agent (HA) with information about
   its current point of attachment (care-of address).  The HA creates
   and maintains binding between the MN's Home Address and the MN's
   Care-of Address.

   In order to register with a HA, the MN needs to know some information
   such as the Home Link prefix, the HA address, the Home Address(es),
   the Home Link prefix length and security association related
   information.

   The aforementioned information may be statically configured.
   However, static provisioning becomes an administrative burden for an
   operator.  Moreover, it does not address load balancing, failover,
   opportunistic home link assignment and assignment of local HAs in
   close proximity to the MN.  Also the ability to react to sudden
   environmental or topological changes is minimal.  Static provisioning
   may not be desirable, in light of these limitations.

   Dynamic assignment of MIPv6 home registration information is a
   desirable feature for ease of deployment and network maintenance.
   For this purpose, the AAA infrastructure, which is used for access
   authentication, can be leveraged to assign some or all of the
   necessary parameters.  The Diameter server in Access Service
   Provider's (ASP) or in Mobility Service Provider's (MSP) network may
   return these parameters to the AAA client.  Regarding the
   bootstrapping procedures, the AAA client might either be the NAS, in
   case of the integrated scenario, or the HA, in case of the split
   scenario [7].  The terms integrated and split are described in the
   terminology section and were introduced in [8] and [9].


2.  Terminology and Abbreviations

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC2119 [2].

   General mobility terminology can be found in [10].  The following
   additional terms, as defined in [8], are used in this document:

   Access Service Authorizer (ASA):

      A network operator that authenticates a MN and establishes the
      MN's authorization to receive Internet service.




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   Access Service Provider (ASP):

      A network operator that provides direct IP packet forwarding to
      and from the MN.

   Mobility Service Authorizer (MSA):

      A service provider that authorizes MIPv6 service.

   Mobility Service Provider (MSP):

      A service provider that provides MIPv6 service.  In order to
      obtain such service, the MN must be authenticated and authorized
      to obtain the MIPv6 service.

   Split scenario:

      A scenario where the mobility service and the network access
      service are authorized by different entities.

   Integrated Scenario:

      A scenario where the mobility service and the network access
      service are authorized by the same entity.

   Network Access Server (NAS):

      A device that provides an access service for a user to a network.

   Home AAA (HAAA):

      An authentication, authorization and accounting server located in
      user's home network i.e., in the home realm.

   Local AAA (LAAA):

      An authentication, authorization and accounting proxy located in
      the local (ASP) network.

   Visited AAA (VAAA):

      An authentication, authorization and accounting proxy located in a
      visited network i.e., in the visited realm.  In a roaming case,
      the local Diameter proxy has the VAAA role.







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3.  Overview

   This document addresses the authentication, authorization and
   accounting functionality required for the MIPv6 bootstrapping
   solutions outlined in [8] and focuses on the Diameter based AAA
   functionality for the NAS to HAAA communication.

   In the integrated scenario MIPv6 bootstrapping is provided as part of
   the network access authentication procedure.  Figure 1 shows the
   participating entities.


                      +---------------------------+  +-----------------+
                      |Access Service Provider    |  |ASA/MSA/(MSP)    |
                      |(Mobility Service Provider)|  |                 |
                      |                           |  |                 |
                      | +--------+                |  |    +--------+   |
                      | |Local   |      Diameter  |  |    |Home    |   |
                      | |Diameter|<---------------------->|Diameter|   |
                      | |Proxy   |         (*)    |  |    |Server  |   |
                      | +--------+                |  |    +--------+   |
                      |     ^ ^                   |  |        ^        |
                      |     | |                   |  |        |(+)     |
                      |     | |                   |  |        |        |
                      |   Diameter                |  |        v        |
                      |     | |(+)      +-------+ |  |    +-------+    |
                      |     | |         |Home   | |  |    |Home   |    |
                      |     | +-------->|Agent  | |  |    |Agent  |    |
                      |  (*)|           |in ASP | |  |    |in MSP |    |
                      |     v           +-------+ |  |    +-------+    |
   +-------+ IEEE     | +-----------+   +-------+ |  +-----------------+
   |Mobile | 802.1X   | |NAS/Relay  |   |DHCPv6 | |
   |Node   |------------|Diameter   |---|Server | |
   |       | PANA,... | |Client     |(+)|       | |
   +-------+ DHCP     | +-----------+   +-------+ |
             (+)      +---------------------------+

   Legend:
     (*): Functionality in scope of this specification
     (+): Extensions described in other documents.

      Figure 1: Mobile IPv6 Bootstrapping in the Integrated Scenario

   In a typical MIPv6 access scenario, a MN is attached to an ASP's
   network.  During the network attachment procedure, the MN interacts
   with the NAS/Diameter client.  Subsequently, the NAS/Diameter client
   interacts with the Diameter server over the NAS to HAAA interface.




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   When the Diameter server performs the authentication and
   authorization for the network access it also determines whether the
   user is authorized to the MIPv6 service.  Based on the MIPv6 service
   authorization and user's policy profile, the Diameter server may
   return several MIPv6 bootstrapping related parameters to the NAS.
   The NAS to HAAA interface described in this document is not tied to
   DHCPv6 as the only mechanism to convey MIPv6 related configuration
   parameters from the NAS/Diameter client to the mobile node.


4.  Commands, AVPs and Advertising Application Support

4.1.  Advertising Application Support

   This document defines a number of MIPv6 bootstrapping NAS to HAAA
   interface (integrated scenario) related AVPs.  These AVPs can be used
   with present and future Diameter applications, where permitted by the
   command ABNF.  This document does not define a new application.  All
   examples in this document reuse NASREQ [3] and EAP [4] applications.

4.2.  Command Codes

   This document shows re-use of the Diameter NASREQ application [3] and
   the EAP application commands [4] as an example of the MIPv6
   bootstrapping NAS to HAAA interface.  The following commands are used
   to carry MIPv6 related bootstrapping AVPs:


   Command-Name             Abbrev.   Code     Reference  Application

   Diameter-EAP-Request      DER       268      RFC 4072   EAP
   Diameter-EAP-Answer       DEA       268      RFC 4072   EAP

   AA-Request                AAR       265      RFC 4005   NASREQ
   AA-Answer                 AAA       265      RFC 4005   NASREQ


     Figure 2: MIPv6 Bootstrapping NAS to HAAA Interface Command Codes

   When the Re-Auth-Request (RAR), Re-Auth-Answer (RAA), Session-
   Termination-Request (STR), Session-Termination-Answer (STA), Abort-
   Session-Request (ASR), Abort-Session-Answer (ASA), Accounting-Request
   (ACR), and Accounting-Answer (ACA) commands are used together with
   the MIPv6 bootstrapping NAS to HAAA interface, they follow the rules
   defined in RFC 3588 [5] and the rules for the specific Diameter
   application the AVPs defined in this document are used with.  The
   accounting commands use the Application Identifier value of 3
   (Diameter Base Accounting); the others use 0 (Diameter Common



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   Messages).

   All request messages SHOULD contain the User-Name AVP containing the
   identity of the MN in NAI format.  It is out of scope how the NAS
   finds out the MN identity.  The NAS could, for example, use the MN
   identity provided by the network access authentication mechanism.

4.3.  Diameter-EAP-Request (DER)

   The Diameter-EAP-Request (DER) message [4], indicated by the Command-
   Code field set to 268 and the 'R' bit set in the Command Flags field,
   is sent by the NAS to the Diameter server to initiate a network
   access authentication and authorization procedure.  The DER message
   format is the same as defined in [4].  The message MAY include
   optional MIPv6 bootstrapping AVPs:

     <Diameter-EAP-Request> ::= < Diameter Header: 268, REQ, PXY >
                                < Session-Id >
                                { Auth-Application-Id }
                                { Origin-Host }
                                { Origin-Realm }
                                { Destination-Realm }
                                { Auth-Request-Type }

                              * [ MIP6-Agent-Info ]
                              * [ MIP6-Home-Link-Prefix ]
                                [ MIP6-Feature-Vector ]

                                [ User-Name ]
                                [ Destination-Host ]
                                ...
                              * [ AVP ]

4.4.  Diameter-EAP-Answer (DEA)

   The Diameter-EAP-Answer (DEA) message defined in [4], indicated by
   the Command-Code field set to 268 and 'R' bit cleared in the Command
   Flags field, is sent in response to the Diameter-EAP-Request message
   (DER).  If the network access authentication procedure was successful
   then the response MAY include any set of bootstrapping AVPs.

   The DEA message format is the same as defined in [4] with an addition
   of optional MIPv6 bootstrapping AVPs:








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     <Diameter-EAP-Answer> ::= < Diameter Header: 268, PXY >
                               < Session-Id >
                               { Auth-Application-Id }
                               { Auth-Request-Type }
                               { Result-Code }
                               { Origin-Host }
                               { Origin-Realm }

                             * [ MIP6-Agent-Info ]
                             * [ MIP6-Home-Link-Prefix ]
                               [ MIP6-Feature-Vector ]

                               [ User-Name ]
                               ...
                             * [ AVP ]

4.5.  AA-Request (AAR)

   The AA-Request (AAR) message [3], indicated by the Command-Code field
   set to 265 and 'R' bit set in the Command Flags field, is sent by the
   NAS to the Diameter server to initiate a network access
   authentication and authorization procedure.  The AAR message format
   is the same as defined in [3].  The message MAY include optional
   MIPv6 bootstrapping AVPs:

     <AA-Request> ::= < Diameter Header: 265, REQ, PXY >
                      < Session-Id >
                      { Auth-Application-Id }
                      { Origin-Host }
                      { Origin-Realm }
                      { Destination-Realm }
                      { Auth-Request-Type }

                    * [ MIP6-Agent-Info ]
                    * [ MIP6-Home-Link-Prefix ]
                      [ MIP6-Feature-Vector ]

                      [ User-Name ]
                      [ Destination-Host ]
                      ...
                    * [ AVP ]

4.6.  AA-Answer (AAA)

   The AA-Answer (AAA) message, indicated by the Command-Code field set
   to 265 and 'R' bit cleared in the Command Flags field is sent in
   response to the AA-Request (AAR) message for confirmation of the
   result of MIPv6 HA bootstrapping.  If the network access



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   authentication procedure was successful then the response MAY include
   any set of bootstrapping AVPs.

   The AAA message format is the same as defined in [3] with an addition
   of optional MIPv6 bootstrapping AVPs:

     <AA-Answer> ::= < Diameter Header: 265, PXY >
                     < Session-Id >
                     { Auth-Application-Id }
                     { Auth-Request-Type }
                     { Result-Code }
                     { Origin-Host }
                     { Origin-Realm }

                   * [ MIP6-Agent-Info ]
                   * [ MIP6-Home-Link-Prefix ]
                     [ MIP6-Feature-Vector ]

                     [ User-Name ]
                     ...
                   * [ AVP ]

4.7.  Attribute Value Pair Definitions

4.7.1.  MIP6-Agent-Info

   The MIP6-Agent-Info AVP (AVP code TBD) is type of Grouped and
   contains necessary information to assign a HA to the MN.  When the
   MIP6-Agent-Info AVP is present in a message, it MUST contain either
   the MIP-Home-Agent-Address AVP or the MIP-Home-Agent-Host AVP, or
   both AVPs.  The grouped AVP has the following grammar:

   <MIP6-Agent-Info> ::= < AVP Header: TBD >
                         [ MIP-Home-Agent-Address ]
                         [ MIP-Home-Agent-Host ]
                       * [ AVP ]

   If both MIP-Home-Agent-Address and MIP-Home-Agent-Host APVs are
   present in the MIP6-Agent-Info, the MIP-Home-Agent-Address SHOULD
   have a precedence over the MIP-Home-Agent-Host.  The reason for this
   recommendation is that the MIP-Home-Agent-Address points to a
   specific home agent, where as the MIP-Home-Agent-Host may point to a
   group of HAs located at within the same realm.  A Diameter client or
   an agent may use the MIP-Home-Agent-Host AVP, for instance, to find
   out the realm where the HA is located.

   This AVP MAY also be attached by the NAS or by intermediating
   Diameter proxies in a request message when sent to the Diameter



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   server as a hint of a locally assigned HA.  This AVP MAY also be
   attached by the intermediating Diameter proxies in a reply message
   from the Diameter server, if locally assigned HAs are authorized by
   the Diameter server.

4.7.2.  MIP-Home-Agent-Address AVP

   The MIP-Home-Agent-Address AVP (AVP Code 334 [6]) is of type Address
   and contains the HA address.  The Diameter server MAY decide to
   assign a HA to the MN that is in close proximity to the point of
   attachment (e.g., determined by the NAS-Identifier AVP).  There may
   be other reasons for dynamically assigning HAs to the MN, for example
   to share the traffic load.

4.7.3.  MIP-Home-Agent-Host AVP

   The MIP-Home-Agent-Host AVP (AVP Code 348 [6]) is of type Grouped and
   contains the identity of the assigned HA.  Both the Destination-Realm
   and the Destination-Host AVP of the HA are included in the grouped
   AVP.  The usage of this AVP is equivalent to the MIP-Home-Agent-
   Address AVP but offers an additional level of indirection by using
   the DNS infrastructure.

   Depending on the actual deployment and DNS configuration the
   Destination-Host AVP MAY represent one or more home agents.  It is
   RECOMMENDED that the Destination-Host AVP identifies exactly one HA.

4.7.4.  MIP6-Home-Link-Prefix AVP

   The MIP6-Home-Link-Prefix AVP (AVP Code TBD) is of type OctetString
   and contains the Mobile IPv6 home network prefix information in
   network byte order.  The home network prefix MUST be encoded as the
   8-bit prefix length information followed by the 128-bit field for the
   available home network prefix.

4.7.5.  MIP6-Feature-Vector AVP

   The MIP6-Feature-Vector AVP (AVP Code TBD) is of type Unsigned64 and
   contains a 64 bit flags field of supported capabilities of the NAS/
   ASP.  Sending and receiving the MIP6-Feature-Vector AVP with value 0
   MUST be supported, although that does not provide much guidance about
   specific needs of bootstrapping.

   The NAS MAY include this AVP to indicate capabilities of the NAS/ASP
   to the Diameter server.  For example, the NAS may indicate that a
   local HA can be provided.  Similarly, the Diameter server MAY include
   this AVP to inform the NAS/ASP about which of the NAS/ASP indicated
   capabilities are supported or authorized by the ASA/MSA(/MSP).



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   The following capabilities are defined in this document:


   MIP6_INTEGRATED (0x0000000000000001)

      When this flag is set by the NAS then it means that the Mobile
      IPv6 integrated scenario bootstrapping functionality is supported
      by the NAS.  When this flag is set by the Diameter server then the
      Mobile IPv6 integrated scenario bootstrapping is supported by the
      Diameter server.

   LOCAL_HOME_AGENT_ASSIGNMENT (0x0000000000000002)

      When this flag is set in the request message, a local home agent
      outside the home realm is requested and may be assigned to the MN.
      When this flag is set by the Diameter server in the answer
      message, then the assignment of local HAs is authorized by the
      Diameter server.

      A local HA may be assigned by the NAS, LAAA or VAAA depending on
      the network architecture and the deployment.

   The following examples show how the LOCAL_HOME_AGENT_ASSIGNMENT
   capability and the MIP-Agent-Info AVP are used to assign HAs, either
   a local HA (L-HA) or a home network HA (H-HA).  Below is an example
   of a request message combinations as seen by the HAAA:

    LOCAL-bit  HA-Info  Meaning

      0          -      ASP or [LV]AAA is not able to assign a L-HA
      0         L-HA    Same as above. HA-Info must be ignored
      1          -      ASP or [LV]AAA can/wishes to assign a L-HA
      1         L-HA    Same as above but ASP or [LV]AAA also
                        provides a hint of the assigned L-HA

   Then the same as above for an answer message combinations as seen by
   the NAS:

    LOCAL-bit  HA-Info  Meaning

      0          -      No HA allowed -> no mobility
      0         H-HA    L-HA is not allowed. HAAA assigns a H-HA
      1          -      L-HA is allowed. No HAAA or [LV]AAA assigned HA
      1         L-HA    L-HA is allowed. [LV]AAA also assigns a L-HA
      1         H-HA    L-HA is allowed. HAAA also assigns a HA
      1         H-HA    L-HA is allowed. HAAA assigns a H-HA and
              + L-HA    [LV]AAA also assigns also a L-HA




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5.  Examples

5.1.  Home Agent Assignment by the NAS

   In this scenario we consider the case where the NAS wishes to
   allocate a local HA to the MN.  The NAS will also inform the Diameter
   server about the HA address it has assigned to the visiting MN (e.g.,
   2001:db8:1:c020::1).  The Diameter-EAP-Request message therefore has
   the MIP6-Feature-Vector with the LOCAL_HOME_AGENT_ASSIGNMENT and the
   MIP6_INTEGRATED set.  The MIP6-Agent-Info AVP contains the MIP-Home-
   Agent-Address AVP with the address of the proposed HA.


                                                                Diameter
   NAS                                                            Server
    |                                                                 |
    |  Diameter-EAP-Request                                           |
    |  MIP6-Feature-Vector=(LOCAL_HOME_AGENT_ASSIGNMENT               |
    |                       | MIP6_INTEGRATED)                        |
    |  MIP6-Agent-Info{                                               |
    |       MIP-Home-Agent-Address(2001:db8:1:c020::1)}               |
    |  }                                                              |
    |  Auth-Request-Type=AUTHORIZE_AUTHENTICATE                       |
    |  EAP-Payload(EAP Start)                                         |
    |---------------------------------------------------------------->|
    |                                                                 |
    |                                                                 |
    :              ...more EAP Request/Response pairs...              :
    |                                                                 |
    |                                                                 |
    |                                            Diameter-EAP-Answer  |
    |               MIP6-Feature-Vector=(LOCAL_HOME_AGENT_ASSIGNMENT  |
    |                                    | MIP6_INTEGRATED)           |
    |                                   Result-Code=DIAMETER_SUCCESS  |
    |                                       EAP-Payload(EAP Success)  |
    |                                         EAP-Master-Session-Key  |
    |                                           (authorization AVPs)  |
    |                                                           ...   |
    |<----------------------------------------------------------------|
    |                                                                 |

                  Figure 3: Home Agent Assignment by NAS

   Depending on the Diameter server configuration and user's
   subscription profile, the Diameter server either accepts or rejects
   the proposal of locally HA allocated by the NAS will be used.  In our
   example, the Diameter server accepts the proposal and the the MIP6-
   Feature-Vector AVP with LOCAL_HOME_AGENT_ASSIGNMENT flag (together



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   with the MIP6_INTEGRATED flag) is set and returned to the NAS.

5.2.  Home Agent Assignment by the Diameter Server

   In this scenario we consider the case where the NAS supports the
   Diameter MIPv6 integrated scenario as defined in this document but
   does not offer local HA assignment.  Hence, the MIP6-Feature-Vector
   AVP only has the MIP6_INTEGRATED flag set.  The Diameter server
   allocates a HA to the mobile node and conveys the address in the MIP-
   Home-Agent-Address AVP that is encapsulated in the MIP6-Agent-Info
   AVP.  Additionally, the MIP6-Feature-Vector AVP has the
   MIP6_INTEGRATED flag set.


                                                                Diameter
   NAS                                                            Server
    |                                                                 |
    |  Diameter-EAP-Request                                           |
    |  MIP6-Feature-Vector=(MIP6_INTEGRATED)                          |
    |  Auth-Request-Type=AUTHORIZE_AUTHENTICATE                       |
    |  EAP-Payload(EAP Start)                                         |
    |---------------------------------------------------------------->|
    |                                                                 |
    |                                                                 |
    :              ...more EAP Request/Response pairs...              :
    |                                                                 |
    |                                                                 |
    |                                            Diameter-EAP-Answer  |
    |                                               MIP6-Agent-Info{  |
    |         MIP-Home-Agent-Address(2001:db8:6000:302::1/64)         |
    |                                                              }  |
    |                          MIP6-Feature-Vector=(MIP6_INTEGRATED)  |
    |                                   Result-Code=DIAMETER_SUCCESS  |
    |                                       EAP-Payload(EAP Success)  |
    |                                         EAP-Master-Session-Key  |
    |                                           (authorization AVPs)  |
    |                                                           ...   |
    |<----------------------------------------------------------------|
    |                                                                 |

            Figure 4: Home Agent Assignment by Diameter Server

5.3.  Home Agent Assignment by NAS or Diameter Server

   This section shows a message flow for the MIPv6 integrated scenario
   bootstrapping where the NAS informs the Diameter server that it is
   able to locally assign a HA to the MN.  The Diameter server is able
   to provide a HA to the MN but also authorizes the assignment of local



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   HA.  The Diameter server then replies to the NAS with HA related
   bootstrapping information.

   Whether the NAS/ASP then offers a locally assigned HA or the Diameter
   server assigned HA to the MN is, in this example, based on the local
   ASP policy.


                                                                Diameter
   NAS                                                            Server
    |                                                                 |
    |  Diameter-EAP-Request                                           |
    |  MIP6-Feature-Vector=(LOCAL_HOME_AGENT_ASSIGNMENT               |
    |                       | MIP6_INTEGRATED)                        |
    |  MIP6-Agent-Info{                                               |
    |       MIP-Home-Agent-Address(2001:db8:1:c020::1)}               |
    |  }                                                              |
    |  Auth-Request-Type=AUTHORIZE_AUTHENTICATE                       |
    |  EAP-Payload(EAP Start)                                         |
    |---------------------------------------------------------------->|
    |                                                                 |
    |                                                                 |
    :              ...more EAP Request/Response pairs...              :
    |                                                                 |
    |                                                                 |
    |                                            Diameter-EAP-Answer  |
    |                                               MIP6-Agent-Info{  |
    |               MIP-Home-Agent-Address(2001:db8:6000:302::1/64)}  |
    |               MIP6-Feature-Vector=(LOCAL_HOME_AGENT_ASSIGNMENT  |
    |                                    | MIP6_INTEGRATED)           |
    |                                   Result-Code=DIAMETER_SUCCESS  |
    |                                       EAP-Payload(EAP Success)  |
    |                                         EAP-Master-Session-Key  |
    |                                           (authorization AVPs)  |
    |                                                           ...   |
    |<----------------------------------------------------------------|
    |                                                                 |

         Figure 5: Home Agent Assignment by NAS or Diameter Server

   If the Diameter server does not accept locally assigned HA, the
   Diameter returns the MIP6-Feature-Vector AVP with
   LOCAL_HOME_AGENT_ASSIGNMENT bit unset and HA address it plans to
   allocate for the MN.







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6.  AVP Occurrence Tables

6.1.  AAR, AAA, DER and DEA Commands AVP Table

   The following table lists the additional MIPv6 bootstrapping NAS to
   HAAA interface AVPs that may optionally be present in the AAR and AAA
   Commands [3] or in the DER and DEA Commands [4].



                                     +-----------------------+
                                     |     Command-Code      |
                                     |-----+-----+-----+-----+
      Attribute Name                 | AAR | AAA | DER | DEA |
      -------------------------------|-----+-----|-----+-----+
      MIP6-Agent-Info                | 0+  | 0+  | 0+  | 0+  |
      MIP6-Feature-Vector            | 0-1 | 0-1 | 0-1 | 0-1 |
      MIP6-Home-Link-Prefix          | 0+  | 0+  | 0+  | 0+  |
                                     +-----+-----+-----+-----+

            Figure 6: AAR, AAA, DER and DEA Commands AVP Table


7.  MIPv6 Bootstrapping NAS to HAAA Interface AVPs

   This section defines AVPs that are specific to Diameter MIPv6
   bootstrapping NAS to HAAA interface and MAY be included in the
   Diameter EAP [4] and the NASREQ [3] application messages.  The
   Diameter AVP rules are defined in the Diameter Base [5], Section 4.
   These AVP rules are observed in AVPs defined in this section.

   The following table describes the Diameter AVPs, their AVP Code
   values, types, possible flag values, and whether the AVP MAY be
   encrypted.  The Diameter base [5] specifies the AVP Flag rules for
   AVPs in Section 4.5.
















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                                            +---------------------+
                                            |    AVP Flag rules   |
                                            +----+-----+----+-----+----+
                     AVP  Section           |    |     |SHLD|MUST |    |
  Attribute Name     Code Defined Data Type |MUST| MAY |NOT |NOT  |Encr|
  ------------------------------------------+----+-----+----+-----+----+
  MIP6-Agent-Info    TBD  4.7.1  Grouped    |    |  P  |    | V,M | Y  |
  MIP-Home-Agent-                           |    |     |    |     |    |
   Address           334  4.7.2  Address    |    |  P  |    | V,M | Y  |
  MIP-Home-Agent-                           |    |     |    |     |    |
   Host              348  4.7.3  Grouped    |    |  P  |    | V,M | Y  |
  MIP6-Feature-                             |    |     |    |     |    |
   Vector            TBD  4.7.5  Unsigned64 |    |  P  |    | V,M | Y  |
  MIP6-Home-Link-    TBD  4.7.4  OctetString|    |  P  |    | V,M | Y  |
   Prefix                                   |    |     |    |     |    |
  ------------------------------------------+----+-----+----+-----+----+

                      Figure 7: AVP Flag Rules Table


8.  IANA Considerations

8.1.  Registration of new AVPs

   This specification defines the following new AVPs:

     MIP6-Agent-Info                is set to TBD
     MIP6-Feature-Vector            is set to TBD
     MIP6-Home-Link-Prefix          is set to TBD

8.2.  New Registry: Mobility Capability

   IANA is requested to create a new registry for the Mobility
   Capability as described in Section 4.7.5.

  Token                             | Value                | Description
  ----------------------------------+----------------------+------------
  MIP6_INTEGRATED                   | 0x0000000000000001   | [RFC TBD]
  LOCAL_HOME_AGENT_ASSIGNMENT       | 0x0000000000000002   | [RFC TBD]
  Available for Assignment via IANA | 2^x                  |

   Allocation rule: Only numeric values that are 2^x (power of two) are
   allowed based on the allocation policy described below.

   Following the policies outlined in [1] new values with a description
   of their semantic for usage with the MIP6-Feature-Vector AVP together
   with a Token will be assigned after Expert Review initiated by the
   O&M Area Directors in consultation with the DIME working group chairs



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   or the working group chairs of a designated successor working group.
   Updates can be provided based on expert approval only.  A designated
   expert will be appointed by the O&M Area Directors.  No mechanism to
   mark entries as "deprecated" is envisioned.  Based on expert approval
   it is possible to delete entries from the registry.


9.  Security Considerations

   The security considerations for the Diameter interaction required to
   accomplish the integrated scenario are described in [11].
   Additionally, the security considerations of the Diameter base
   protocol [5], Diameter NASREQ application [3] / Diameter EAP [4]
   application (with respect to network access authentication and the
   transport of keying material) are applicable to this document.  This
   document does not introduce new security vulnerabilities.


10.  Acknowledgements

   This document is heavily based on the ongoing work for RADIUS MIPv6
   interaction.  Hence, credits go to respective authors for their work
   with draft-ietf-mip6-radius.  Furthermore, the author would like to
   thank the authors of draft-le-aaa-diameter-mobileipv6 (Franck Le,
   Basavaraj Patil, Charles E. Perkins, Stefano Faccin) for their work
   in context of MIPv6 Diameter interworking.  Their work influenced
   this document.  Jouni Korhonen would like to thank Academy of Finland
   and TEKES MERCoNe Project for providing funding to work on this
   document.  Julien Bournelle would like to thank GET/INT since he
   began to work on this document while he was in their employ.  Authors
   would also like to acknowledge Raymond Hsu for his valuable feedback
   on local HA assignment and Wolfgang Fritsche for his thorough review.
   Finally, we would like to Domagoj Premec for his review comments.

   We would like to thank Alper Yegin, Robert Marks, David Frascone for
   their comments at the second WGLC.


11.  References

11.1.  Normative References

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

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




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   [3]   Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter
         Network Access Server Application", RFC 4005, August 2005.

   [4]   Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
         Authentication Protocol (EAP) Application", RFC 4072,
         August 2005.

   [5]   Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko,
         "Diameter Base Protocol", RFC 3588, September 2003.

   [6]   Calhoun, P., Johansson, T., Perkins, C., Hiller, T., and P.
         McCann, "Diameter Mobile IPv4 Application", RFC 4004,
         August 2005.

11.2.  Informative References

   [7]   Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6
         Bootstrapping in Split Scenario", RFC 5026, October 2007.

   [8]   Patel, A. and G. Giaretta, "Problem Statement for bootstrapping
         Mobile IPv6 (MIPv6)", RFC 4640, September 2006.

   [9]   Giaretta, G., Guardini, I., Demaria, E., Bournelle, J., and R.
         Lopez, "AAA Goals for Mobile IPv6",
         draft-ietf-mext-aaa-ha-goals-00 (work in progress),
         December 2007.

   [10]  Manner, J. and M. Kojo, "Mobility Related Terminology",
         RFC 3753, June 2004.

   [11]  Chowdhury, K. and A. Yegin, "MIP6-bootstrapping for the
         Integrated Scenario",
         draft-ietf-mip6-bootstrapping-integrated-dhc-05 (work in
         progress), July 2007.


Authors' Addresses

   Jouni Korhonen
   TeliaSonera
   Teollisuuskatu 13
   Sonera  FIN-00051
   Finland

   Email: jouni.korhonen@teliasonera.com






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   Julien Bournelle
   Orange Labs
   38-4O rue du general Leclerc
   Issy-Les-Moulineaux  92794
   France

   Email: julien.bournelle@orange-ftgroup.com


   Hannes Tschofenig
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  02600
   Finland

   Phone: +358 (50) 4871445
   Email: Hannes.Tschofenig@nsn.com
   URI:   http://www.tschofenig.com


   Charles E. Perkins

   Phone: +1-650-496-4402
   Email: charliep@computer.org


   Kuntal Chowdhury
   Starent Networks
   30 International Place
   Tewksbury  MA  01876
   US

   Phone: +1 214 550 1416
   Email: kchowdhury@starentnetworks.com

















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