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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RFC 5447         Diameter MIPv6 NAS-to-HAAA Interaction    February 2009


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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RFC 5447         Diameter MIPv6 NAS-to-HAAA Interaction    February 2009


                                    +-----------+
                                    |  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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RFC 5447         Diameter MIPv6 NAS-to-HAAA Interaction    February 2009


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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RFC 5447         Diameter MIPv6 NAS-to-HAAA Interaction    February 2009


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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RFC 5447         Diameter MIPv6 NAS-to-HAAA Interaction    February 2009


  [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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RFC 5447         Diameter MIPv6 NAS-to-HAAA Interaction    February 2009


Authors' Addresses

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

  EMail: [email protected]


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

  EMail: [email protected]


  Hannes Tschofenig
  Nokia Siemens Networks
  Linnoitustie 6
  Espoo  02600
  Finland

  EMail: [email protected]
  URI:   http://www.tschofenig.priv.at


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

  EMail: [email protected]


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

  EMail: [email protected]





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