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Versions: (draft-tschofenig-dime-mip6-integrated) 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 5447

Diameter Maintenance and                               J. Korhonen (ed.)
Extensions (DIME)                                            TeliaSonera
Internet-Draft                                              J. Bournelle
Intended status: Informational                                   GET/INT
Expires: December 3, 2006                                  H. Tschofenig
                                                                 Siemens
                                                              C. Perkins
                                                                   Nokia
                                                            K. Chowdhury
                                                        Starent Networks
                                                               June 2006


            The NAS - HAAA Interface for MIPv6 Bootstrapping
                 draft-ietf-dime-mip6-integrated-01.txt

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
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   This Internet-Draft will expire on December 3, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   A Mobile IPv6 node requires a home agent address, a home address, and



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   IPsec security association with its home agent before it can start
   utilizing Mobile IPv6 service.  RFC 3775 requires that some or all of
   these parameters are statically configured.  Ongoing 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 usage of Diameter to facilitate Mobile IPv6
   bootstrapping for the NAS - HAAA interface.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology and Abbreviations  . . . . . . . . . . . . . . . .  3
   3.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Commands, AVPs and Advertising Application Support . . . . . .  6
     4.1.  Advertising Application Support  . . . . . . . . . . . . .  6
     4.2.  Command Codes  . . . . . . . . . . . . . . . . . . . . . .  6
     4.3.  Diameter-EAP-Request (DER) . . . . . . . . . . . . . . . .  7
     4.4.  Diameter-EAP-Answer (DEA)  . . . . . . . . . . . . . . . .  7
     4.5.  AA-Request (AAR) . . . . . . . . . . . . . . . . . . . . .  8
     4.6.  AA-Answer (AAA)  . . . . . . . . . . . . . . . . . . . . .  9
     4.7.  New AVPs . . . . . . . . . . . . . . . . . . . . . . . . . 10
       4.7.1.  MIP6-Home-Agent-Address AVP  . . . . . . . . . . . . . 10
       4.7.2.  MIP6-Home-Agent-FQDN AVP . . . . . . . . . . . . . . . 10
       4.7.3.  MIP6-Home-Link-Prefix AVP  . . . . . . . . . . . . . . 10
       4.7.4.  MIP4-Home-Agent-Address AVP  . . . . . . . . . . . . . 11
     4.8.  Capability Advertisement . . . . . . . . . . . . . . . . . 11
   5.  Diameter Client and Server Behavior During MIPv6
       Bootstrapping  . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.1.  Client (NAS) Behavior  . . . . . . . . . . . . . . . . . . 12
     5.2.  Server Behavior  . . . . . . . . . . . . . . . . . . . . . 13
     5.3.  Example Message Flows  . . . . . . . . . . . . . . . . . . 14
   6.  AVP Occurrence Tables  . . . . . . . . . . . . . . . . . . . . 15
     6.1.  DER and DEA Commands AVP Table . . . . . . . . . . . . . . 15
     6.2.  AAR and AAA Commands AVP Table . . . . . . . . . . . . . . 16
   7.  MIPv6 Bootstrapping NAS - HAAA Interface AVPs  . . . . . . . . 16
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 17
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17
   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   11. Revision history . . . . . . . . . . . . . . . . . . . . . . . 18
   12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     12.1. Normative References . . . . . . . . . . . . . . . . . . . 18
     12.2. Informative References . . . . . . . . . . . . . . . . . . 19
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
   Intellectual Property and Copyright Statements . . . . . . . . . . 21




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1.  Introduction

   Mobile IPv6 specification [RFC3775] requires a Mobile Node (MN) to
   perform registration with a home agent with information about its
   current point of attachment (Care-of Address).  The home agent
   creates and maintains binding between the MN's Home Address and the
   MN's Care-of Address.

   In order to register with a home agent, the MN needs to know some
   information such as, the Home Link prefix, the home agent Address,
   the Home Address(es), the Home Link prefix Length and security
   related information in order to later secure the Binding Update.

   The aforementioned set of information may be statically provisioned
   in the MN.  However, static provisioning of this information has its
   drawbacks.  It increases provisioning and network maintenance becomes
   easily burden for an operator.  Moreover, static provisioning does
   not allow load balancing, failover, opportunistic home link
   assignment etc.  For example, the user may be accessing the network
   from a location that may be geographically far away from the
   preconfigured home link; the administrative burden to configure the
   MNs with the respective addresses is large and the ability to react
   on environmental changes is minimal.  In these situations static
   provisioning may not be desirable.

   Dynamic assignment of Mobile IPv6 home registration information is a
   desirable feature for ease of deployment and network maintenance.
   For this purpose, the Diameter 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 home agent, in case of the
   split scenario [I-D.ietf-mip6-bootstrapping-split].  The terms
   integrated and split are described in the terminology section and
   were introduced in [RFC4640] and [I-D.ietf-mip6-aaa-ha-goals].


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 [RFC2119].

   General mobility terminology can be found in [RFC3753].  The
   following additional terms, as defined in [RFC4640], are used in this
   document:



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   Access Service Authorizer (ASA):

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

   Access Service Provider (ASP):

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

   Mobility Service Authorizer (MSA):

      A service provider that authorizes Mobile IPv6 service.

   Mobility Service Provider (MSP):

      A service provider that provides Mobile IPv6 service.  In order to
      obtain such service, the mobile node must be authenticated and
      authorized to obtain the Mobile IPv6 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.


3.  Overview

   This document addresses the authentication, authorization and
   accounting functionality required by for the MIPv6 bootstrapping as
   outlined in the MIPv6 bootstrapping problem statement document (see
   [RFC4640]).  This document focuses on the AAA functionality for the
   NAS - HAAA interface.



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   The subsequent text outlines the AAA interaction between the
   participating entities in the integrated scenario.  In the integrated
   scenario MIPv6 bootstrapping is provided as part of the network
   access authentication procedure.  Figure 1 shows the participating
   entities.  This document, however, only concentrates on the NAS,
   possible local Diameter proxies and the home Diameter server.


                      +---------------------------+  +-----------------+
                      |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     v     +-------+ |  |    +-------+    |
   +-------+ IEEE     | +-----------+   +-------+ |  +-----------------+
   |Mobile | 802.1X   | |NAS/Relay  |   |DHCPv6 | |
   |Node   |----------+-|Diameter   |---|Server | |
   |       | PANA,... | |Client     |   |       | |
   +-------+ DHCP     | +-----------+   +-------+ |
                      +---------------------------+

      Figure 1: Mobile IPv6 Bootstrapping in the Integrated Scenario

   In a typical Mobile IPv6 access scenario, as shown above, the MN is
   attached to an ASP's network.  During the network attachment
   procedure, the NAS/Diameter client interacts with the mobile node.
   As shown in Figure 1, the authentication and authorization happens
   via the Diameter infrastructure.

   At the time of authentication the user for the network access, the
   Diameter server in the MSA detects that the user is also authorized
   for Mobile IPv6 access.  Based on the MSA's policy, the Diameter
   server may allocate several parameters to the MN for use during the
   subsequent Mobile IPv6 protocol interaction with the home agent.

   Depending on the details of the solution interaction with the DHCPv6



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   server may be required, as described in
   [I-D.ietf-mip6-bootstrapping-integrated-dhc].  However, the solution
   described in this document is not dependant on the DHCPv6 as the only
   possible MIPv6 bootstrapping method.


4.  Commands, AVPs and Advertising Application Support

   This section describes command codes, defines AVPs and advertised
   application identifiers for the Diameter MIPv6 bootstrapping in the
   NAS - HAAA interface.

4.1.  Advertising Application Support

   Diameter nodes conforming to this specification SHOULD include the
   value of 1 (NASREQ application) or 5 (EAP application) in the Auth-
   Application-Id or the Acct-Application-Id AVP of the Capabilities-
   Exchange-Request and Capabilities-Exchange-Answer commands [RFC3588].

   The value of zero (0) SHOULD be used as the Application-Id in all
   STR/STA, ACR/ACA, ASR/ASA, and RAR/RAA commands, because these
   commands are defined in the Diameter base protocol and no additional
   mandatory AVPs for those commands are defined in this document.

4.2.  Command Codes

   This document re-uses the Diameter Base protocol [RFC3588], Diameter
   NASREQ application [RFC4072] and EAP commands .  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 - 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 Diameter MIPv6 bootstrapping NAS - HAAA interface, they follow
   the rules in the Diameter NASREQ [RFC4005], EAP [RFC4072] and BASE



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   [RFC3588] applications.  The accounting commands use Application
   Identifier value of 3 (Diameter Base Accounting); the others use 0
   (Diameter Common Messages).

4.3.  Diameter-EAP-Request (DER)

   The Diameter-EAP-Request (DER) command [RFC4072], indicated by the
   Command-Code field set to 268 and the 'R' bit set in the Command
   Flags field, may be sent by the NAS to the Diameter server providing
   network access authentication and authorization services.  At the
   same time with the network access authentication and authorization
   the NAS MAY indicate the access network capability of MIPv6
   bootstrapping and optionally also the capability of a local home
   agent assignment.

   The message format is the same as defined in [RFC4072] with an
   addition of possible MIPv6 bootstrapping NAS - HAAA interface AVPs to
   indicate capabilities of the NAS and ASP:



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

                                [ MIP6-Home-Agent-Address ]
                                [ MIP6-Home-Agent-FQDN ]
                                [ MIP6-Home-Link-Prefix ]
                                [ MIP4-Home-Agent-Address ]

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

                  Figure 3: Diameter EAP Request Command

4.4.  Diameter-EAP-Answer (DEA)

   The Diameter-EAP-Answer (DEA) message define in [RFC4072], 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 was successfully authenticated
   then the response SHOULD include the MIP6-Home-Agent-Address AVP,
   MIP6-Home-Link-Prefix, MIP6-Home-Agent-FQDN and MIP4-Home-Agent-



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   address AVPs.

   The message format is the same as defined in [RFC4072] with an
   addition of MIPv6 bootstrapping NAS - HAAA interface AVPs:


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

                               [ MIP6-Home-Agent-Address ]
                               [ MIP6-Home-Agent-FQDN ]
                               [ MIP6-Home-Link-Prefix ]
                               [ MIP4-Home-Agent-Address ]

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

                   Figure 4: Diameter EAP Answer Command

4.5.  AA-Request (AAR)

   The AA-Request (AAR) message, indicated by the Command-Code field set
   to 265 and 'R' bit set in the Command Flags field, may be sent by the
   NAS to the Diameter server providing network access configuration
   services.  At the same time with the network access configuration the
   NAS MAY request home agent assignment, to authorize for mobility
   service usage and optionally to indicate the support of possible
   local home agent assignment.

   The message format is the same as defined in [RFC4005] with an
   addition of MIPv6 bootstrapping NAS - HAAA interface AVPs:














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

                      [ MIP6-Home-Agent-Address ]
                      [ MIP6-Home-Agent-FQDN ]
                      [ MIP6-Home-Link-Prefix ]
                      [ MIP4-Home-Agent-Address ]

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

                       Figure 5: AA Request Command

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 was
   successfully authenticated then the response SHOULD include the MIP6-
   Home-Agent-Address AVP, MIP6-Home-Link-Prefix, MIP6-Home-Agent-FQDN
   and MIP4-Home-Agent-address AVPs.

   The message format is the same as defined in [RFC4005] with an
   addition of MIPv6 bootstrapping NAS - HAAA interface AVPs:




















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

                     [ MIP6-Home-Agent-Address ]
                     [ MIP6-Home-Agent-FQDN ]
                     [ MIP6-Home-Link-Prefix]
                     [ MIP4-Home-Agent-address ]

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

                        Figure 6: AA Answer Command

4.7.  New AVPs

4.7.1.  MIP6-Home-Agent-Address AVP

   The MIP6-Home-Agent-Address AVP (AVP Code TBD) is of type OctetString
   and contains the Mobile IPv6 home agent address and the prefix length
   of the said address.  The AVP is a discriminated union, representing
   IPv6 address in network byte order.  The first two octets of this AVP
   represents the home link prefix length followed by 16 octets of the
   IPv6 address.

   The Diameter server MAY decide to assign a MIPv6 home agent to the MN
   that is in close proximity to the point of attachment (e.g.
   determined by the NAS-Identifier).  There may be other reasons for
   dynamically assigning home agents to the MN, for example to share the
   traffic load.  The AVP also contains the prefix length so that the MN
   can easily infer one of the possible Home Link prefixes from the home
   agent address.

4.7.2.  MIP6-Home-Agent-FQDN AVP

   The MIP6-Home-Agent-FQDN AVP (AVP Code TBD) is of type UTF8String and
   contains the FQDN of a Mobile IPv6 home agent.

4.7.3.  MIP6-Home-Link-Prefix AVP

   The MIP6-Home-Link-Prefix AVP (AVP Code TBD) is of type OctetString
   and contains the Mobile IPv6 home link prefix.  There may be reasons
   for the Diameter server to dynamically assigning home link prefix to



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   the MN, for example one that is in close proximity to the point of
   attachment.

4.7.4.  MIP4-Home-Agent-Address AVP

   The MIP4-Home-Agent-Address AVP (AVP Code TBD) is of type OctetString
   and contains the IPv4 home agent address and the prefix length of the
   said address.  The AVP is a discriminated union, representing IPv4
   address in network byte order.  The first two octets of this AVP
   represents the home link prefix length followed by 4 octets of the
   IPv4 address.

   The Diameter server MAY decide to assign a MIPv4 home agent to the MN
   in a case where dual stack Mobile IP is supported
   [I-D.ietf-mip6-nemo-v4traversal].

4.8.  Capability Advertisement

   The NAS/ASP may include any MIPv6 bootstrapping AVPs in the Diameter
   EAP or NASREQ application request messages to advertise its MIPv6
   bootstrapping capabilities to the Diameter server.  The use of
   capability advertisement is optional.

   The capability advertisement may also be used as an explicit hint to
   the Diameter server about locally allocated mobility agents or home
   links.  In this case e.g. the MIP6-Home-Agent-Address AVP would
   contain the IP address of the locally allocated home agent.  If the
   NAS/ASP does not have any specific home agent to offer during the
   access authentication time the IP address in the respective
   bootstrapping AVPs MUST be set to unspecified address (::/128).  The
   MIP6-Home-Agent-FQDN SHOULD NOT be used for the capability
   advertisement if it does not already name a locally allocated Home
   Agent.


5.  Diameter Client and Server Behavior During MIPv6 Bootstrapping

   This section describes the Diameter server and client behavior in
   case of the MIPv6 bootstrapping in the integrated scenario.  The text
   does several assumptions for brevity.

   o  The Diameter server is assumed to support at least the Diameter
      BASE, EAP and NASREQ applications.
   o  The Diameter client (i.e. the NAS) is assumed to support at least
      the Diameter BASE, EAP and NASREQ applications.






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   o  The MN uses such network access authentication method and
      credentials that are supported by the NAS/ASP and ASA/MSA.
   o  The MN has been provisioned with a Mobile IPv6 service.
   o  The capability exchange has already completed, thus the NAS and
      the Diameter server share the knowledge of mutually supported
      applications.  Cases where the ASA/MSA do not support MIPv6
      bootstrapping are not discussed.  In these cases the NAS has no
      other choice than to carry out the network access authentication
      as defined in the Diameter EAP or NASREQ applications.

5.1.  Client (NAS) Behavior

   If the ASP/NAS does not support MIPv6 integrated scenario
   bootstrapping then the NAS either selects the basic Diameter NASREQ
   or EAP application depending on which authentication method gets
   used.  Naturally after a successful or a failed authentication the
   NAS does not have to carry out any MIPv6 bootstrapping related
   procedures.

   Next we describe two different scenarios for the network access
   authentication when the ASP/NAS supports MIPv6 integrated scenario
   bootstrapping.

   1) The MN uses some EAP-based method (e.g. 802.11i/802.1X) to
      authenticate to the network.  In this scenario the NAS uses
      commands originally defined for the EAP application.
   2) The MN uses some other than EAP-based method to authenticate to
      the network.  In this scenario the NAS uses the Diameter NASREQ
      application commands.

   The NAS may include the MIPv6 NAS - HAAA AVPs in the DER or in the
   AAR messages.  This serves two purposes.  Firstly the NAS/ASP may
   advertise its MIPv6 bootstrapping capability to the Diameter server.
   Secondly the NAS/ASP may suggest locally allocated home agents to the
   Diameter server.  Whether the locally allocated home agents are
   allowed for the forthcoming MIPv6 session depends on the MN's
   subscription and the ASA/MSA(/MSP) policies.  If the NAS/ASP only
   wants to advertise its capability for local agent allocation but does
   not want to provide any specific agent at this point of time (e.g.
   that is left for later steps during the actual Mobile IP
   registration) the AVPs MUST contain values described in Section 4.8.

   If the network access authentication failed the NAS receives
   appropriate error codes as defined for the Diameter EAP or NASREQ
   applications.  The NAS does not allow the MN to access the network
   and does not do any MIPv6 bootstrapping related procedures.

   If the network access authentication completed successfully, the NAS



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   looks for home agent defining AVPs in the reply messages (either DEA
   or AAA depending on the used authentication method).  The NAS
   associates the received bootstrapping information to the MN that
   initiated the access authentication and stores the information
   internally (storing time is determined by the ASP policy).  The
   stored bootstrapping information is then available for the NAS and
   the DHCP relay for later step during the MN bootstrapping process.

   The actual bootstrapping from the MN point of view takes place after
   the network access authentication has completed.  The bootstrapping
   may be realized e.g. using DHCP as defined in
   [I-D.ietf-mip6-bootstrapping-integrated-dhc] and [RFC2132].

   The MN has no consistent way of indicating to the NAS that it
   supports MIPv6 integrated scenario way of bootstrapping during the
   network access authentication.  Subsequently the NAS has no
   possibilities to find out whether the terminal attempting to
   authenticate is actually a MN with MIPv6 bootstrapping functionality
   prior the network access authentication has completed.  Thus it is
   possible that the NAS initiates MIPv6 integrated scenario
   bootstrapping configuration even if the MN is not able to make any
   use of it later.  The Diameter server in the ASA/MSA might be able to
   detect this situation during the authentication phase based on MN's
   identity -- assuming the ASA is able to verify from the MSA(/MSP)
   whether the MN has been provisioned with a MIPv6 service.

5.2.  Server Behavior

   If the NAS/ASP does not support MIPv6 integrated scenario
   bootstrapping then the NAS either selects the Diameter NASREQ or EAP
   application depending on which access authentication method the MN
   has to use to authenticate.  In this case the NAS does not either
   include any MIPv6 NAS - HAAA interface AVPs as a hint of the
   bootstrapping capability in the NAS/ASP.  The Diameter server in the
   ASA/MSA(/MSP) detects this case (based on AVPs that serve as a
   capability hint) and does not have to carry out any MIPv6
   bootstrapping related procedures.  However, as the capability
   advertisement mechanism described in this document serves only as an
   optional hint, the Diameter server should not entirely rely on the
   received capability hints but also base its working logic on
   subscription information and general MSA(/MSP) policies.

   Next we describe two different scenarios for the network access
   authentication when the NAS/ASP supports MIPv6 integrated scenario
   bootstrapping.






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   1) The MN uses some EAP-based method to authenticate to the network
      and the NAS uses Diameter EAP application commands.  Depending on
      the ASA/MSA(/MSP) policy the Diameter server SHOULD assign a
      Mobile IPv6 home agent to the MN and include corresponding MIP6-
      Home-Agent-Address, the MIP6-Home-Agent-FQDN AVPs and the MIP6-
      Home-Link-Prefix in the final DEA message.
   2) The MN uses some other than EAP-based method to authenticate to
      the network and the NAS uses Diameter NASREQ application commands.
      Depending on the ASA/MSA(/MSP) policy the Diameter server SHOULD
      assign a Mobile IPv6 home agent to the MN and include
      corresponding MIP6-Home-Agent-Address, the MIP6-Home-Agent-FQDN
      AVPs and the MIP6-Home-Link-Prefix in the final AAA message.

   If the Diameter request message contained any MIPv6 NAS -HAAA
   interface AVPs the Diameter server should regard them as a hint of
   the MIPv6 bootstrapping capability in the NAS/ASP.  Any of these AVPs
   may contain values as described in Section 4.8 which indicate the
   NAS/ASP would like to locally allocate a home agent or a home link to
   the MN.  The Diameter server may or may not honor the NAS/ASP hint
   based on the MN's subscription and ASA/MAS(/MSP) policies.

5.3.  Example Message Flows

   This section shows basic message flows of MIPv6 integrated scenario
   bootstrapping and dynamic home agent assignment.  In the Figure 7
   network access authentication is based on EAP (e.g. 802.11i/802.1X).
   The NAS informs the home Diameter server that home agent assignment
   in the foreign network is possible.  The Diameter server assigns the
   MN a home agent either in the home MSP or in the ASP.  The assignment
   procedure is out of scope of this document.  The Diameter server then
   replies to the NAS with home agent related bootstrapping information.




















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   NAS                          Local proxy                  Home server
    |                                |                                |
    |  Diameter-EAP-Request          |                                |
    |  MIP6-Home-Agent-Address(IPv6 address)                          |
    |  MIP6-Home-Agent-FQDN=visited_ha6.example.com                   |
    |  MIP4-Home-Agent-Address(IPv4 address)                          |
    |  MIP6-Home-Link-Prefix=(IPv6 prefix)                            |
    |  Auth-Request-Type=AUTHORIZE_AUTHENTICATE                       |
    |  EAP-Payload(EAP Start)        |                                |
    |------------------------------->|------------------------------->|
    |                                |                                |
    |                                :                                |
    :              ...more EAP Request/Response pairs...              :
    |                                :                                |
    |                                |                                |
    |                                |           Diameter-EAP-Answer  |
    |                          MIP6-Home-Agent-Address(IPv6 address)  |
    |                            MIP6-Home-Agent-FQDN=ha.example.com  |
    |                                |  Result-Code=DIAMETER_SUCCESS  |
    |                                |      EAP-Payload(EAP Success)  |
    |                                |        EAP-Master-Session-Key  |
    |                                |          (authorization AVPs)  |
    |                                |                          ...   |
    |<-------------------------------|<-------------------------------|
    |                                |                                |

     Figure 7: MIPv6 integrated scenario bootstrapping and NAS - HAAA
       interface example when EAP is used for access authentication


6.  AVP Occurrence Tables

6.1.  DER and DEA Commands AVP Table

   The following table lists the additional MIPv6 bootstrapping NAS -
   HAAA interface AVPs that optionally may be present in the DER and DEA
   Commands, as defined in this document and in [RFC4072].














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                                     +---------------+
                                     |  Command-Code |
                                     |-------+-------+
      Attribute Name                 |  DER  |  DEA  |
      -------------------------------+-------+-------+
      MIP6-Home-Agent-Address        |  0-1  |  0-1  |
      MIP6-Home-Agent-FQDN           |  0-1  |  0-1  |
      MIP4-Home-Agent-Address        |  0-1  |  0-1  |
      MIP6-Home-Link-Prefix          |  0-1  |  0-1  |
                                     +-------+-------+


                 Figure 8: DER and DEA Commands AVP table

6.2.  AAR and AAA Commands AVP Table

   The following table lists the additional MIPv6 bootstrapping NAS -
   HAAA interface AVPs that may optionally be present in the AAR and AAA
   Commands, as defined in this document and in [RFC4005].



                                     +---------------+
                                     |  Command-Code |
                                     |-------+-------+
      Attribute Name                 |  AAR  |  AAA  |
      -------------------------------|-------+-------|
      MIP6-Home-Agent-Address        |  0-1  |  0-1  |
      MIP6-Home-Agent-FQDN           |  0-1  |  0-1  |
      MIP4-Home-Agent-Address        |  0-1  |  0-1  |
      MIP6-Home-Link-Prefix          |  0-1  |  0-1  |
                                     +-------+-------+

                 Figure 9: AAR and AAA Commands AVP table


7.  MIPv6 Bootstrapping NAS - HAAA Interface AVPs

   This section defines the AVPs that are specific to Diameter MIPv6
   bootstrapping NAS - HAAA interface and MAY be included in the
   Diameter EAP [RFC4072] and the NASREQ [RFC4005] applications messages
   listed in Section 4 of this document.  The Diameter AVP rules are
   defined in the Diameter Base [RFC3588], 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 [RFC3588] specifies the AVP Flag rules



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   for AVPs in section 4.5.

                                            +--------------------+
                                            |    AVP Flag rules  |
                                            +----+-----+----+----+----+
                     AVP  Section           |    |     |SHLD|MUST|    |
   Attribute Name    Code Defined Data Type |MUST| MAY | NOT|NOT |Encr|
   -----------------------------------------+----+-----+----+----+----+
   MIP6-Home-Agent-  TBD  4.7.1  OctetString| M  |  P  |    | V  | Y  |
       Address                              |    |     |    |    |    |
   MIP6-Home-Agent-  TBD  4.7.2  UTF8String | M  |  P  |    | V  | Y  |
       FQDN                                 |    |     |    |    |    |
   MIP4-Home-Agent-  TBD  4.7.4  OctetString| M  |  P  |    | V  | Y  |
       address                              |    |     |    |    |    |
   MIP6-Home-Link-   TBD  4.7.3  Unsigned32 | M  |  P  |    | V  | Y  |
       Prefix                               |    |     |    |    |    |
   -----------------------------------------+----+-----+----+----+----+

                      Figure 10: AVP flag rules table


8.  IANA Considerations

   This specification defines the following new AVPs:

     MIP6-Home-Agent-Address          is set to TBD
     MIP6-Home-Agent-FQDN             is set to TBD
     MIP4-Home-Agent-Address          is set to TBD
     MIP6-Home-Link-Prefix            is set to TBD


9.  Security Considerations

   The security considerations for the Diameter interaction required to
   accomplish the integrated scenario are described in
   [I-D.ietf-mip6-bootstrapping-integrated-dhc] .  Additionally, the
   security considerations of the Diameter base protocol [RFC3588],
   Diameter NASREQ application [RFC4005] / Diameter EAP [RFC4072]
   application (with respect to network access authentication and the
   transport of keying material) are applicable to this document.


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-00.txt.  Furthermore, the author would
   like to thank the authors of draft-le-aaa-diameter-mobileipv6-04.txt



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   (Franck Le, Basavaraj Patil, Charles E. Perkins, Stefano Faccin) for
   their work in context of MIPv6 Diameter interworking.  Their work
   influenced this document.


11.  Revision history

   The following changes were made to the -01 version of the draft:

   o  The document title was changed to "The NAS - HAAA Interface for
      MIPv6 Bootstrapping".
   o  Added HAAA and NAS to terminology section".
   o  Changed NAS application to NASREQ application.".
   o  Changed "Integrated Scenario" to NAS-HAAA interface".
   o  The separate Diameter Application-ID for MIPv6 bootstrapping
      (MIP6BSTI) got removed and all bootstrapping is based on Diameter
      EAP application and Diameter NAS application.
   o  MIPv6-Bootstrapping-Feature AVP was removed and General text
      regarding to the capability advertisement based on optional AVPs
      was added.
   o  The capability exchange was modified so that the NAS may suggest a
      specific HA to the AAAH.  Original MIPv6-Bootstrapping-Feature AVP
      was replaces with a possibility to include any bootstrapping AVP
      to the Diameter AAR or DER messages as a capability and local
      allocation hint.


12.  References

12.1.  Normative References

   [I-D.ietf-mip6-aaa-ha-goals]
              Giaretta, G., "AAA Goals for Mobile IPv6",
              draft-ietf-mip6-aaa-ha-goals-03 (work in progress),
              September 2006.

   [I-D.ietf-mip6-bootstrapping-integrated-dhc]
              Chowdhury, K. and A. Yegin, "MIP6-bootstrapping via DHCPv6
              for the Integrated Scenario",
              draft-ietf-mip6-bootstrapping-integrated-dhc-01 (work in
              progress), June 2006.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", March 1997.

   [RFC3588]  Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
              Arkko, "Diameter Base Protocol", RFC 3588, September 2003.




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   [RFC3775]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
              in IPv6", RFC 3775, June 2004.

   [RFC4640]  Patel, A. and G. Giaretta, "Problem Statement for
              bootstrapping Mobile IPv6 (MIPv6)", RFC 4640,
              September 2006.

12.2.  Informative References

   [I-D.ietf-mip6-bootstrapping-split]
              Giaretta, G., "Mobile IPv6 bootstrapping in split
              scenario", draft-ietf-mip6-bootstrapping-split-03 (work in
              progress), October 2006.

   [I-D.ietf-mip6-nemo-v4traversal]
              Soliman, H., "Mobile IPv6 support for dual stack Hosts and
              Routers (DSMIPv6)", draft-ietf-mip6-nemo-v4traversal-02
              (work in progress), June 2006.

   [RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
              Extensions", RFC 2132, March 1997.

   [RFC3753]  Manner, J. and M. Kojo, "Mobility Related Terminology",
              RFC 3753, June 2004.

   [RFC4005]  Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
              "Diameter Network Access Server Application", RFC 4005,
              August 2005.

   [RFC4072]  Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
              Authentication Protocol (EAP) Application", RFC 4072,
              August 2005.


Authors' Addresses

   Jouni Korhonen
   TeliaSonera
   Teollisuuskatu 13
   Sonera  FIN-00051
   Finland

   Email: jouni.korhonen@teliasonera.com








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   Julien Bournelle
   GET/INT
   9 rue Charles Fourier
   Evry  91011
   France

   Email: julien.bournelle@int-evry.fr


   Hannes Tschofenig
   Siemens
   Otto-Hahn-Ring 6
   Munich, Bavaria  81739
   Germany

   Email: Hannes.Tschofenig@siemens.com
   URI:   http://www.tschofenig.com


   Charles E. Perkins
   Nokia

   Email: charliep@iprg.nokia.com


   Kuntal Chowdhury
   Starent Networks

   Email: kchowdhury@starentnetworks.com






















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