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PROPOSED STANDARD
Errata Exist
Network Working Group                                   J. Korhonen, Ed.
Request for Comments: 5447                        Nokia Siemens Networks
Category: Standards Track                                   J. Bournelle
                                                             Orange Labs
                                                           H. Tschofenig
                                                  Nokia Siemens Networks
                                                              C. Perkins
                                                                WiChorus
                                                            K. Chowdhury
                                                        Starent Networks
                                                           February 2009


                         Diameter Mobile IPv6:
    Support for Network Access Server to Diameter Server Interaction

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (http://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

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 be 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 (AAA) infrastructures.  This document
   describes MIPv6 bootstrapping using the Diameter Network Access
   Server to home AAA server interface.




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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology and Abbreviations  . . . . . . . . . . . . . . . .  3
   3.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   4.  Commands, Attribute-Value Pairs, and Advertising
       Application Support  . . . . . . . . . . . . . . . . . . . . .  6
     4.1.  Advertising Application Support  . . . . . . . . . . . . .  6
     4.2.  Attribute-Value Pair Definitions . . . . . . . . . . . . .  6
       4.2.1.  MIP6-Agent-Info AVP  . . . . . . . . . . . . . . . . .  6
       4.2.2.  MIP-Home-Agent-Address AVP . . . . . . . . . . . . . .  7
       4.2.3.  MIP-Home-Agent-Host AVP  . . . . . . . . . . . . . . .  7
       4.2.4.  MIP6-Home-Link-Prefix AVP  . . . . . . . . . . . . . .  8
       4.2.5.  MIP6-Feature-Vector AVP  . . . . . . . . . . . . . . .  8
   5.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     5.1.  Home Agent Assignment by the NAS . . . . . . . . . . . . . 10
     5.2.  Home Agent Assignment by the Diameter Server . . . . . . . 11
     5.3.  Home Agent Assignment by the NAS or Diameter Server  . . . 11
   6.  Attribute-Value Pair Occurrence Tables . . . . . . . . . . . . 12
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
     7.1.  Registration of New AVPs . . . . . . . . . . . . . . . . . 13
     7.2.  New Registry: Mobility Capability  . . . . . . . . . . . . 13
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   9.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 14
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
     10.2. Informative References . . . . . . . . . . . . . . . . . . 15
























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1.  Introduction

   The Mobile IPv6 (MIPv6) specification [RFC3775] 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 the binding between the MN's home
   address and the MN's care-of address.

   In order to register with an 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, or 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 the Access Service
   Provider's (ASP's) or Mobility Service Provider's (MSP's) network may
   return these parameters to the AAA client.  Regarding the
   bootstrapping procedures, the AAA client might either be the Network
   Access Server, in case of the integrated scenario, or the HA, in case
   of the split scenario [RFC5026].  The terms "integrated" and "split"
   are described in the following terminology section and were
   introduced in [RFC4640] and [AAA].

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 RFC 2119 [RFC2119].

   General mobility terminology can be found in [RFC3753].  The
   following additional terms are either borrowed from [RFC4640] or
   [RFC5026] or are introduced in this document:

   Access Service Authorizer (ASA):

      A network operator that authenticates an 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 do so.

   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
      the 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 (see Figure 1).







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3.  Overview

   This document addresses the Authentication, Authorization, and
   Accounting (AAA) functionality required for the MIPv6 bootstrapping
   solutions outlined in [RFC4640], and focuses on the Diameter-based
   AAA functionality for the NAS-to-HAAA (home AAA) server
   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     |(+)|       | |
   +-------+ IKEv2,   | +-----------+   +-------+ |
             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, an 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 network access, it also determines whether the user
   is authorized for the MIPv6 service.  Based on the MIPv6 service
   authorization and the 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
   the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) as the only
   mechanism to convey MIPv6-related configuration parameters from the
   NAS/Diameter client to the mobile node.

   While this specification addresses the bootstrapping of MIPv6 HA
   information and possibly the assignment of the home link prefix, it
   does not address how the Security Association (SA) between the MN and
   the HA for MIPv6 purposes is created.  The creation or the use of the
   SA between the MN and the HA takes places after the procedures
   described in this specification, and therefore are out of scope.

4.  Commands, Attribute-Value Pairs, and Advertising Application Support

4.1.  Advertising Application Support

   This document does not define a new application.  On the other hand,
   it defines a number of attribute-value pairs (AVPs) used in the
   interface between NAS to HAAA for the integrated scenario of MIPv6
   bootstrapping.  These AVPs can be used with any present and future
   Diameter applications, where permitted by the command ABNF.  The
   examples using existing applications and their commands in the
   following sections are for informational purposes only.  The examples
   in this document reuse the Extensible Authentication Protocol (EAP)
   [RFC4072] application and its respective commands.

4.2.  Attribute-Value Pair Definitions

4.2.1.  MIP6-Agent-Info AVP

   The MIP6-Agent-Info AVP (AVP code 486) is of type Grouped and
   contains necessary information to assign an 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, the MIP-Home-Agent-Host AVP, or both
   AVPs.  The grouped AVP has the following modified ABNF (as defined in
   [RFC3588]):

       MIP6-Agent-Info ::= < AVP-Header: 486 >
                         *2[ MIP-Home-Agent-Address ]
                           [ MIP-Home-Agent-Host ]
                           [ MIP6-Home-Link-Prefix ]
                         * [ AVP ]




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   If both the 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, whereas the MIP-Home-Agent-Host may point to a
   group of HAs located within the same realm.  A Diameter client or
   agent may use the MIP-Home-Agent-Host AVP, for instance, to find out
   in which realm the HA is located.

   The ABNF allows returning up to two MIPv6 HA addresses.  This is a
   useful feature for deployments where the HA has both IPv6 and IPv4
   addresses, and particularly addresses Dual Stack Mobile IPv6
   (DSMIPv6) deployment scenarios [DSMIPv6].

   The MIP6-Agent-Info AVP MAY also be attached by the NAS or by the
   intermediating Diameter proxies in a request message when sent to the
   Diameter 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.  There MAY be multiple instances
   of the MIP6-Agent-Info AVP in Diameter messages, for example, in
   cases where the NAS receives HA information from an MN's home network
   and locally allocated HA information from the visited network.  See
   Section 4.2.5 for further discussion on possible scenarios.

4.2.2.  MIP-Home-Agent-Address AVP

   The MIP-Home-Agent-Address AVP (AVP Code 334 [RFC4004]) is of type
   Address and contains the IPv6 or IPv4 address of the MIPv6 HA.  The
   Diameter server MAY decide to assign an 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.

4.2.3.  MIP-Home-Agent-Host AVP

   The MIP-Home-Agent-Host AVP (AVP Code 348 [RFC4004]) is of type
   Grouped and contains the identity of the assigned MIPv6 HA.  Both the
   Destination-Realm and the Destination-Host AVPs of the HA are
   included in the grouped AVP.  The usage of the MIP-Home-Agent-Host
   AVP is equivalent to the MIP-Home-Agent-Address AVP but offers an
   additional level of indirection by using the DNS infrastructure.  The
   Destination-Host AVP is used to identify an HA, and the Destination-
   Realm AVP is used to identify the realm where the HA is located.

   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.



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   It is RECOMMENDED that the MIP-Home-Agent-Host AVP is always included
   in the MIP6-Agent-Info AVP.  In this way, the HA can be associated
   with the corresponding realm of the Diameter entity that added the
   MIP6-Agent-Info AVP using the Destination-Realm AVP, which is
   included in the MIP-Home-Agent-Host AVP.

4.2.4.  MIP6-Home-Link-Prefix AVP

   The MIP6-Home-Link-Prefix AVP (AVP Code 125) is of type OctetString
   and contains the Mobile IPv6 home network prefix information in a
   network byte order.  The home network prefix MUST be encoded as the
   8-bit prefix length information (one octet) followed by the 128-bit
   field (16 octets) for the available home network prefix.  The
   trailing bits of the IPv6 prefix after the prefix length bits MUST be
   set to zero (e.g., if the prefix length is 60, then the remaining 68
   bits MUST be set to zero).

   The HAAA MAY act as a central entity managing prefixes for MNs.  In
   this case, the HAAA returns to the NAS the prefix allocated to the
   MN.  The NAS/ASP then delivers the home link prefix to the MN using,
   e.g., mechanisms described in [INTEGRATED].  The NAS/ASP MAY propose
   to the HAAA a specific prefix to allocate to the MN by including the
   MIP6-Home-Link-Prefix AVP in the request message.  However, the HAAA
   MAY override the prefix allocation hint proposed by the NAS/ASP and
   return a different prefix in the response message.

4.2.5.  MIP6-Feature-Vector AVP

   The MIP6-Feature-Vector AVP (AVP Code 124) 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).

   The following capabilities are defined in this document:










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   MIP6_INTEGRATED (0x0000000000000001)

      When this flag is set by the NAS, 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
   (referred to as LOCAL-bit in the examples) capability and the MIP-
   Agent-Info AVP (referred to as HA-Info in the examples) are used to
   assign HAs -- either a local HA (L-HA) or a home network HA (H-HA).
   Below are examples of request message combinations as seen by the
   HAAA:

    LOCAL-bit  HA-Info  Meaning

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

   The same as above but for answer message combinations as seen by the
   NAS:

  LOCAL-bit  HA-Info  Meaning

    0          -      No HA assignment allowed for HAAA or [LV]AAA.
    0         H-HA    L-HA is not allowed.  HAAA assigns an 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 an L-HA.
    1         H-HA    L-HA is allowed.  HAAA also assigns an HA.
    1         H-HA    L-HA is allowed.  HAAA assigns an H-HA and
            + L-HA    [LV]AAA also assigns an L-HA.

   An NAS should expect to receive multiple MIP6-Agent-Info AVPs.



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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/VAAA                                                       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 2: Home Agent Assignment by the NAS

   Depending on the Diameter server's configuration and the user's
   subscription profile, the Diameter server either accepts or rejects
   the local HA allocated by the NAS.  In our example, the Diameter
   server accepts the proposal, and the MIP6-Feature-Vector AVP with
   LOCAL_HOME_AGENT_ASSIGNMENT flag (together with the MIP6_INTEGRATED
   flag) is set and returned to the NAS.



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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 an 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)         |
    |                                                              }  |
    |                          MIP6-Feature-Vector=(MIP6_INTEGRATED)  |
    |                                   Result-Code=DIAMETER_SUCCESS  |
    |                                       EAP-Payload(EAP Success)  |
    |                                         EAP-Master-Session-Key  |
    |                                           (authorization AVPs)  |
    |                                                           ...   |
    |<----------------------------------------------------------------|
    |                                                                 |

          Figure 3: Home Agent Assignment by the Diameter Server

5.3.  Home Agent Assignment by the NAS or Diameter Server

   This section shows another message flow for the MIPv6 integrated
   scenario bootstrapping where the NAS informs the Diameter server that
   it is able to locally assign an HA to the MN.  The Diameter server is
   able to provide an HA to the MN but also authorizes the assignment of
   the local HA.  The Diameter server then replies to the NAS with
   HA-related bootstrapping information.




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   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/VAAA                                                       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)}  |
    |               MIP6-Feature-Vector=(LOCAL_HOME_AGENT_ASSIGNMENT  |
    |                                    | MIP6_INTEGRATED)           |
    |                                   Result-Code=DIAMETER_SUCCESS  |
    |                                       EAP-Payload(EAP Success)  |
    |                                         EAP-Master-Session-Key  |
    |                                           (authorization AVPs)  |
    |                                                           ...   |
    |<----------------------------------------------------------------|
    |                                                                 |

       Figure 4: Home Agent Assignment by the NAS or Diameter Server

   If the Diameter server does not allow the MN to use a locally
   assigned HA, the Diameter server returns to the MN the MIP6-Feature-
   Vector AVP with the LOCAL_HOME_AGENT_ASSIGNMENT bit unset and the HA
   address it allocated.

6.  Attribute-Value Pair Occurrence Tables

   Figure 5 lists the MIPv6 bootstrapping NAS-to-HAAA interface AVPs
   along with a specification determining how many of each new AVP may
   be included in a Diameter command.  They may be present in any
   Diameter application request and answer commands, where permitted by
   the command ABNF.



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                                     +-----------+
                                     |  Command  |
                                     |-----+-----+
      Attribute Name                 | Req | Ans |
      -------------------------------|-----+-----|
      MIP6-Agent-Info                | 0+  | 0+  |
      MIP6-Feature-Vector            | 0-1 | 0-1 |
                                     +-----+-----+

          Figure 5: Generic Request and Answer Commands AVP Table

7.  IANA Considerations

7.1.  Registration of New AVPs

   This specification defines the following AVPs that have been
   allocated from a normal Diameter AVP Code space (values >= 256):

     MIP6-Agent-Info                is set to 486

   The following new AVPs are to be allocated from RADIUS Attribute Type
   space [RFC2865] so that they are RADIUS backward-compatible (AVP Code
   values between 0-255):

     MIP6-Feature-Vector            is set to 124
     MIP6-Home-Link-Prefix          is set to 125

7.2.  New Registry: Mobility Capability

   IANA has created a new registry for the Mobility Capability as
   described in Section 4.2.5.

   Token                             | Value               | Description
   ----------------------------------+---------------------+------------
   MIP6_INTEGRATED                   | 0x0000000000000001  | [RFC5447]
   LOCAL_HOME_AGENT_ASSIGNMENT       | 0x0000000000000002  | [RFC5447]
   Available for Assignment via IANA | 2^x                 |

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

   Following the example policies described in [RFC5226], new values for
   the Mobility Capability Registry will be assigned based on the
   "Specification Required" policy.  No mechanism to mark entries as
   "deprecated" is envisioned.





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8.  Security Considerations

   The security considerations for the Diameter interaction required to
   accomplish the integrated scenario are described in [INTEGRATED].
   Additionally, the security considerations for the Diameter base
   protocol [RFC3588], the Diameter NASREQ application [RFC4005], and
   the Diameter EAP application (with respect to network access
   authentication and the transport of keying material) [RFC4072] are
   applicable to this document.  Developers should insure that special
   attention is paid to configuring the security associations protecting
   the messages that enable the global positioning and allocation of
   home agents, for instance, as outlined in Section 5.

   Furthermore, the Diameter messages may be transported between the NAS
   and the Diameter server via one or more AAA brokers or Diameter
   agents (such as proxies).  In this case, the AAA communication from
   the NAS to the Diameter server relies on the security properties of
   the intermediate AAA brokers and Diameter agents.

9.  Acknowledgments

   This document is heavily based on the ongoing work for RADIUS MIPv6
   interaction.  Hence, credits go to respective authors for their work
   with "RADIUS Mobile IPv6 Support" (November 2008).  Furthermore, the
   authors of this document would like to thank the authors of "Diameter
   Mobile IPv6 Application" (November 2004) -- Franck Le, Basavaraj
   Patil, Charles E. Perkins, and Stefano Faccin -- for their work in
   the context of MIPv6 Diameter interworking.  Their work influenced
   this document.  Jouni Korhonen would like to thank the Academy of
   Finland and TEKES MERCoNe Project for providing funding to work on
   this document while he was with TeliaSonera.  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.  Additionally, we would
   like to Domagoj Premec for his review comments.

   Finally, we would like to thank Alper Yegin, Robert Marks, and David
   Frascone for their comments at the second WG Last Call.












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10.  References

10.1.  Normative References

   [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2865]     Rigney, C., Willens, S., Rubens, A., and W. Simpson,
                 "Remote Authentication Dial In User Service (RADIUS)",
                 RFC 2865, June 2000.

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

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

   [RFC4004]     Calhoun, P., Johansson, T., Perkins, C., Hiller, T.,
                 and P. McCann, "Diameter Mobile IPv4 Application",
                 RFC 4004, August 2005.

   [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.

10.2.  Informative References

   [AAA]         Giaretta, G., Guardini, I., Demaria, E., Bournelle, J.,
                 and R. Lopez, "AAA Goals for Mobile IPv6", Work
                 in Progress, May 2008.

   [DSMIPv6]     Solimand, H., "Mobile IPv6 Support for Dual Stack Hosts
                 and Routers (DSMIPv6)", Work in Progress,
                 December 2008.

   [INTEGRATED]  Chowdhury, K. and A. Yegin, "MIP6-bootstrapping for the
                 Integrated Scenario", Work in Progress, April 2008.

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






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

   [RFC5026]     Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile
                 IPv6 Bootstrapping in Split Scenario", RFC 5026,
                 October 2007.

   [RFC5226]     Narten, T. and H. Alvestrand, "Guidelines for Writing
                 an IANA Considerations Section in RFCs", BCP 26,
                 RFC 5226, May 2008.








































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Authors' Addresses

   Jouni Korhonen (editor)
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  FIN-02600
   Finland

   EMail: jouni.nospam@gmail.com


   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

   EMail: Hannes.Tschofenig@nsn.com
   URI:   http://www.tschofenig.priv.at


   Charles E. Perkins
   WiChorus Inc.
   3590 North First St., Suite 300
   San Jose, CA  95134
   US

   EMail: charliep@wichorus.com


   Kuntal Chowdhury
   Starent Networks
   30 International Place
   Tewksbury, MA  01876
   US

   EMail: kchowdhury@starentnetworks.com





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