Diameter Mobile IPv6: Support for Home Agent to Diameter Server Interaction

Performing the Mobile IPv6 protocol , requires the Mobile Node (MN) to own a Home Address (HoA) and to have an assigned Home Agent (HA) to the MN. The MN needs to register with the HA in order to enable its reachability and mobility, when away from its home link. The registration process itself may require an establishment of IPsec security associations (SA) and cryptographic material between the MN and the HA. Alternatively, the registration process may be secured using a mobility message authentication option, which enables IPv6 mobility in a MN without having to establish an IPsec SA with its HA. Providing the collection of home address, HA address and keying material is generally referred to as the Mobile IPv6 bootstrapping problem . The purpose of this specification is to provide Diameter support for the interaction between the HA and the Authentication, Authorization, and Accounting (AAA) server. This specification satisfies the requirements defined in for the bootstrapping problem in the split scenario and also specifies Diameter support for the Authentication Protocol for Mobile IPv6 . The Diameter support defined in this specification also applies to Dual Stack Mobile IPv6 . From a Mobility Service Provider (MSP) perspective, it is important to verify that the MN is authenticated and authorized to utilize Mobile IPv6 service, and is accounted for those. Only when the MN is authenticated and authorized, the MSP allows the bootstrapping of Mobile IPv6 parameters. Thus, prior to processing the Mobile IPv6 registrations, the HA participates in the authentication of the MN to verify the MN's identity. The HA also participates in the Mobile IPv6 authorization process involving the Diameter infrastructure. The HA, due to its role in traffic forwarding, may also perform accounting for the Mobile IPv6 service provided to the MN. This document enables the following functionality: Verifying the MN's identity. As a Diameter client supporting the new Diameter Mobile IPv6 application, the HA may need to support more than one authentication type depending on the environment. Although the authentication is performed by the AAA server there is an impact for the HA as different set of command codes are needed for the respective authentication procedures. The HA must verify that the user is authorized to the Mobile IPv6 service using the assistance of the MSP Diameter servers. This is accomplished through the use of new Diameter applications specifically designed for performing Mobile IPv6 authorization decisions. This document defines required AAA procedures and requires the HA to support them and to participate in this authorization signaling. For accounting purposes and capacity planning, it is required that the HA provides accounting reports to the Diameter infrastructure and thus to support the related Diameter accounting procedures. The management of the mobility services may require the Diameter server or the HA to terminate the Mobile IPv6 service before the binding expires. This document defines procedures for the AAA based session management. depicts the reference architecture for this document.

AAA Server Support | Interaction | (this document) v +---------+ +---------------+ | Mobile | Front-End Protocol |Home Agent / | | Node |<-------------------->|Diameter Client| +---------+ IKEv2 or RFC 4285 +---------------+ ]]> Mobile IPv6 signaling between the MN and the HA can be protected using two different mechanisms, namely using IPsec or the Authentication Protocol for Mobile IPv6 . For these two approaches several different authentication and key exchange solutions are available. When IPsec is used to protect Mobile IPv6 signaling messages, Internet Key Exchange v2 (IKEv2) is used for the setup of the IPsec SAs. IKEv2 supports Extensible Authentication Protocol (EAP) based initiator authentication, certificates and pre-shared secrets. Alternatively, the Authentication Protocol for Mobile IPv6 uses a mechanism that is very similar to the one used for protecting Mobile IPv4 signaling messages. The ability to use different credentials and methods to authenticate the MN has an impact on the AAA interactions between the HA (acting as a Diameter client) and the Diameter Server. This specification is only limited to the following MN authentication methods: IKEv2 usage with EAP Mobile IPv6 Authentication Protocol New authentication mechanisms may be added later by separate specifications. For accounting of Mobile IPv6 services provided to the MN, this specification uses the Diameter Base Protocol accounting defined in .

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 . The Mobile IPv6 bootstrapping terminology is taken from . Additional terminology is defined below: AAA protocol based on Diameter with required EAP support . An authentication, authorization and accounting server located in user's home network i.e., in the home realm.

This specification defines two new Diameter applications and their respective Application Identifiers:

The MIP6I Application Identifier is used when the MN is authenticated and authorized using IKEv2. The MIP6A Application Identifier is used when the MN is authenticated and authorized using the Mobile IPv6 Authentication Protocol. Mobile IPv6 related accounting information generated by the HA uses either the MIP6I or the MIP6A Application Identifier in the case of coupled accounting model. The Diameter Base Accounting Application Identifier (value of 3) is used in case of the split accounting model. Refer to for more information regarding the accounting models.

The use of IKEv2 with EAP between the MN and the HA allows the AAA to authenticate the MN. When EAP is used with IKEv2, the Diameter EAP application logic and procedures, as defined in , are re-used. EAP methods that do not establish a shared key SHOULD NOT be used, as they are subject to a number of man-in-the-middle attacks as stated in Section 2.16 and Section 5 of . AVPs specific to Mobile IPv6 bootstrapping are added to the EAP application commands. shows the message flow involved during the authentication phase when EAP is used. The communication between the mobile node and the home agent use the conventions defined in . Similarly, the communication between the home agent and the Diameter server use the conventions defined in .

| | | | | | HDR, SAr1, KEr, Nr, [CERTREQ](2)| | |<--------------------------------| | | | | | HDR, SK{IDi,[CERTREQ,] [IDr,] | | | [CP(CFG_REQUEST),] | | | SAi2, TSi, TSr} (3) | DER (EAP-Response) (4) + | |-------------------------------->| MIP6 Bootstrapping AVPs | | |------------------------->| | | | | | DEA (EAP-Request) (5) | | HDR, SK{IDr, [CERT,] AUTH, EAP} |<-------------------------| |<------------------------------- | | | | | | HDR, SK{EAP} | | |-------------------------------->| DER (EAP-Response) | | |------------------------->| | | | | | DEA (EAP-Request) | | HDR, SK{EAP-Request} |<-------------------------| |<--------------------------------| | | | | | HDR, SK{EAP-Response} | | |-------------------------------->| DER (EAP-Response) | | |------------------------->| : ... : ... : | | | | | DEA (EAP-Success) + | | | MIP6 Bootstrapping AVPs | | HDR, SK{EAP-Success} |<-------------------------| |<--------------------------------| | | | | | HDR, SK{AUTH} | | |-------------------------------->| | | | | | HDR, SK{AUTH, [CP(CFG_REPLY,] | | | SAr2, TSi, TSr} | | |<--------------------------------| | | | | ]]> The MN and the HA start the interaction with an IKE_SA_INIT exchange. In this phase cryptographic algorithms are negotiated, nonces and Diffie-Hellman parameters are exchanged. Message (3) starts the IKE_AUTH phase. This second phase authenticates the previous messages, exchanges identities and certificates and establishes the first CHILD_SA. It is used to mutually authenticate the MN (acting as an IKEv2 Initiator) and the HA (acting as an IKEv2 Responder). The identity of the user/MN is provided in the IDi field. The MN indicates its willingness to be authenticated via EAP by omitting the AUTH field in message (3) (see Section 2.16 of ). As part of the authentication process, the MN MAY request a Home-Address, a Home Prefix or suggests one, see , using a CFG_REQUEST payload in the message (3). The HA extracts the IDi field from the message (3) and sends a Diameter-EAP-Request (DER) message (4) towards the authenticating Diameter server. The EAP-Payload AVP contains a EAP-Response/Identity with the identity extracted from the IDi field. This message is routed to the MN's Diameter server/EAP server. The Diameter server selects the EAP method and replies with the Diameter-EAP-Answer (DEA) Message. Depending on the type of EAP method chosen, a number of DER and DEA messages carry the method specific exchanges between the MN and the Diameter server/EAP server. At the end of the EAP authentication phase, the Diameter server indicates the result of the authentication in the Result-Code AVP and provides the corresponding EAP packet (EAP Success or EAP Failure). The last IKEv2 message sent by the HA contains the Home Address or the Home Prefix. In the latter case, a CREATE_CHILD_SA exchange is necessary to setup IPsec SAs for Mobile IPv6 signaling. In some deployment scenarios, the HA may also act as an IKEv2 Responder for a conventional IPsec VPN access. The challenge in this case is that the IKEv2 responder may not know if IKEv2 is used for Mobile IPv6 service or for IPsec VPN access service. A network operator needs to be aware of this limitation. One solution already supported by IKEv2 is to use different responder identities when operating as a conventional IPsec VPN gateway or as a HA. The MN can then indicate the preferred responder type using the appropriate IDr payload in the IKE_AUTH message. Eventually, when the HA receives a Binding Update (BU), the HA authenticates and authorizes the MN. It is RECOMMENDED that the HA sends an accounting request message every time it receives a BU.

shows the message sequence between the MN, the HA and the Diameter server during the registration when Mobile IPv6 Authentication Protocol is used. A BU and a Binding Acknowledgement (BA) messages are used in the binding registration process. Receiving a BU at the HA initiates a MIP6-Request to be sent to the Diameter server. The Diameter server in turn responds with a MIP6-Answer. The HA may assign a Home Address to the MN and provide it to the Diameter server in the MIP-Mobile-Node-Address AVP. According to the MN uses the Mobile Node Identifier Option, specifically the MN-NAI mobility option (as defined in ) to identify itself. The HA MUST copy the MN-NAI mobility option value to the User-Name AVP in the subsequent request messages. The procedure described in this specification for the Mobile IPv6 Authentication Protocol is only needed for the initially received BU for which the HA does not have an existing security association. When the HA receives subsequent BUs, they are processed locally in the HA. It is RECOMMENDED that the HA sends an accounting request message every time it receives a Binding Update. However, the HA MAY re-authorize the MN with the Diameter server at any time depending on the deployment and the local policy. This specification assumes that in the case Mobile IPv6 Authentication Protocol is used, the MN-AAA option is included in the BU as defined in and the Diameter server computes required session keys after having successfully authenticated the MN. The computation of the session keys is out of scope of this specification. Other possible ways of using Mobile IPv6 Authentication Protocol are also out of scope of this specification and would require a new specification to describe the detailed behavior of the HA-AAAH interface and corresponding session key derivation.

|-------------------->| | (Mobile Node Identifier Option, | | | Mobility Message Replay Protection | | | Option, Authentication Option) | | | | | | | MIP6-Answer + MIP6 | | Binding Acknowledgement | Bootstrapping AVPs | |<------------------------------------|<--------------------| | (Mobile Node Identifier Option | | | Mobility Message Replay Protection | | | Option, Authentication Option) | | ]]>

The Diameter server may maintain state or may be stateless. This is indicated in the Auth-Session-State AVP (or its absence). The HA MUST support the Authorization Session State Machine defined in . This specification makes an assumption that each SA created between the MN and the HA as a result of a successful IKEv2 negotiation or a Mobile IPv6 Authentication Protocol exchange correspond to one Diameter session. In IKEv2 case we specifically mean the created IKE SA.

The Session-Termination-Request (STR) message is sent by the HA to inform the Diameter server that an authorized session is being terminated. This means that the HA MUST terminate the corresponding Mobile IPv6 binding and also terminate the corresponding SA.

The Session-Termination-Answer (STA) message is sent by the Diameter server to acknowledge the notification that the session has been terminated.

The Abort-Session-Request (ASR) message is sent by the Diameter server to the HA to terminate the authorized session. This fulfills one of the requirement described in . When the HA receives the ASR message, it MUST terminate the corresponding SA. Subsequently, the HA MUST take further actions to terminate the corresponding Mobile IPv6 binding.

The Abort-Session-Answer (ASA) message is sent by the Home Agent in response to an ASR message.

The HA MUST be able act as a Diameter client collecting accounting records needed for service control and charging. The HA MUST support the accounting procedures (specifically the command codes mentioned below) and the Accounting Session State Machine as defined in . The command codes, exchanged between the HA and Diameter server for accounting purposes, are provided in the following subsections. The Diameter application design guideline defines two separate models for accounting: According to this model, the accounting messages use the Diameter Base Accounting Application Identifier (value of 3). Since accounting is treated as an independent application, accounting commands may be routed separately from the rest of application messages and thus the accounting messages generally end up in a central accounting server. Since Diameter Mobile IPv6 application does not define its own unique accounting commands, this is the preferred choice, since it permits use of centralized accounting for several applications. In this model, the accounting messages will use either the MIP6I or the MIP6A Application Identifiers. This means that accounting messages will be routed like any other Mobile IPv6 application messages. This requires the Diameter server in charge of Mobile IPv6 application to handle the accounting records (e.g., sends them to a proper accounting server). As mentioned above, the preferred choice is to use the split accounting model and thus to choose Diameter Base Accounting Application Identifier (value of 3) for accounting messages.

The Accounting-Request command is sent by the HA to the Diameter server to exchange accounting information regarding the MN with the Diameter server.

The Accounting-Answer command is sent by the Diameter server to the HA to acknowledge an Accounting-Request.

For the use of Mobile IPv6 with IKEv2 and EAP this document reuses the Diameter EAP application commands: Diameter-EAP-Request (DER) and Diameter-EAP-Answer (DEA). This specification extends the existing DER and DEA command ABNFs with a number of AVPs to support Mobile IPv6 split scenario bootstrapping. Other than new additional AVPs and the corresponding additions to the command ABNFs, the Diameter EAP application command ABNFs remain unchanged. The ABNF language is defined in .

The Diameter-EAP-Request (DER) message, indicated by the Command-Code field set to 268 and the 'R' bit set in the Command Flags field, is sent by the HA to the Diameter server to initiate a Mobile IPv6 service authentication and authorization procedure. The Application-ID field of the Diameter Header MUST be set to the Diameter Mobile IPv6 IKE Application ID (value of TDB).

::= < Diameter Header: 268, REQ, PXY > < Session-Id > { Auth-Application-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Auth-Request-Type } [ Destination-Host ] [ NAS-Identifier ] [ NAS-IP-Address ] [ NAS-IPv6-Address ] [ NAS-Port-Type ] [ User-Name ] ... { EAP-Payload } ... [ MIP6-Feature-Vector ] [ MIP6-Agent-Info ] *2[ MIP-Mobile-Node-Address ] [ Chargeable-User-Identity ] [ Service-Selection ] [ QoS-Capability ] * [ QoS-Resources ] ... * [ AVP ] ]]> Mobile IPv6 bootstrapping AVPs are only included in the first DER message send by the HA. The subsequent DER messages required by the EAP-method do not need to include any Mobile IPv6 bootstrapping AVPs. The MN is both authenticated and authorized for the mobility service during the EAP authentication. Thus, the Auth-Request-Type AVP MUST be set to the value AUTHORIZE_AUTHENTICATE.

The Diameter-EAP-Answer (DEA) message, 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). The Application-Id field in the Diameter message header MUST be set to the Diameter Mobile IPv6 IKE Application-Id (value of TBD). If the Mobile IPv6 authentication procedure was successful then the response MAY include any set of bootstrapping AVPs.

::= < Diameter Header: 268, PXY > < Session-Id > { Auth-Application-Id } { Auth-Request-Type } { Result-Code } { Origin-Host } { Origin-Realm } [ User-Name ] [ EAP-Payload ] [ EAP-Reissued-Payload ] [ EAP-Master-Session-Key ] [ EAP-Key-Name ] [ Multi-Round-Time ] ... *2[ MIP-Mobile-Node-Address ] [ MIP6-Feature-Vector ] [ MIP6-Agent-Info ] [ Service-Selection ] * [ QoS-Resources ] [ Chargeable-User-Identity ] ... * [ AVP ] ]]> If the EAP-based authentication and the authorization for the mobility service succeeds, then the Mobile IPv6 bootstrapping AVPs are included in the last DEA message that also carries the EAP-Success EAP payload. The other DEA messages required by the used EAP-method do not include any Mobile IPv6 bootstrapping AVPs.

This section defines the commands that are used for support with the Mobile IPv6 Authentication Protocol. There are multiple ways of deploying and utilizing Mobile IPv6 Authentication Protocol, especially regarding the associated AAA interactions. In order to support multiple deployment models this specification defines the MIP6-Auth-Mode AVP that in the request message tells the mode that the HA supports. This specification defines a method that requires the use of the MN-AAA option with the Mobile IPv6 Authentication Protocol.

The MIP6-Request (MIR), indicated by the Command-Code field set to TBD and the 'R' bit set in the Command Flags field, is sent by the HA, acting as a Diameter client, in order to request the authentication and authorization of a MN. Although the HA provides the Diameter server with replay protection related information, the HA is responsible for the replay protection. The message format is shown below.

::= < Diameter Header: TBD, REQ, PXY > < Session-ID > { Auth-Application-Id } { User-Name } { Destination-Realm } { Origin-Host } { Origin-Realm } { Auth-Request-Type } [ Destination-Host ] [ Origin-State-Id ] [ NAS-Identifier ] [ NAS-IP-Address ] [ NAS-IPv6-Address ] [ NAS-Port-Type ] [ Called-Station-Id ] [ Calling-Station-Id ] [ MIP6-Feature-Vector ] { MIP6-Auth-Mode } [ MIP-MN-AAA-SPI ] [ MIP-MN-HA-SPI ] 1*2{ MIP-Mobile-Node-Address } { MIP6-Agent-Info } { MIP-Careof-Address } [ MIP-Authenticator ] [ MIP-MAC-Mobility-Data ] [ MIP-Timestamp ] [ QoS-Capability ] * [ QoS-Resources ] [ Chargeable-User-Identity ] [ Service-Selection ] [ Authorization-Lifetime ] [ Auth-Session-State ] * [ Proxy-Info ] * [ Route-Record ] * [ AVP ] ]]> If the MN is both authenticated and authorized for the mobility service, then the Auth-Request-Type AVP is set to the value AUTHORIZE_AUTHENTICATE. This is the case when the MIP6-Auth-Mode is set to the value MIP6_AUTH_MN_AAA.

The MIP6-Answer (MIA) message, indicated by the Command-Code field set to TBD and the 'R' bit cleared in the Command Flags field, is sent by the Diameter server in response to the MIP6-Request message. The User-Name AVP MAY be included in the MIA if it is present in the MIR. The Result-Code AVP MAY contain one of the values defined in , in addition to the values defined in . An MIA message with the Result-Code AVP set to DIAMETER_SUCCESS MUST include the MIP-Mobile-Node-Address AVP. The message format is shown below.

::= < Diameter Header: TBD, PXY > < Session-Id > { Auth-Application-Id } { Result-Code } { Origin-Host } { Origin-Realm } { Auth-Request-Type } [ User-Name ] [ Authorization-Lifetime ] [ Auth-Session-State ] [ Error-Message ] [ Error-Reporting-Host ] [ Re-Auth-Request-Type ] [ MIP6-Feature-Vector ] [ MIP-Agent-Info ] *2[ MIP-Mobile-Node-Address ] [ MIP-MN-HA-MSA ] * [ QoS-Resources ] [ Chargeable-User-Identity ] [ Service-Selection ] [ Origin-State-Id ] * [ Proxy-Info ] * [ Redirect-Host ] [ Redirect-Host-Usage ] [ Redirect-Max-Cache-Time ] * [ Failed-AVP ] * [ AVP ] ]]>

To provide support for and for the AVPs in the following subsections are needed. , and defined AVPs are reused whenever possible without changing the existing semantics of those AVPs.

Note 1: The QoS-Capability and the QoS-Resource AVPs are defined in Sections 4.1 and 4.3 of .

The User-Name AVP (AVP Code 1) is of type UTF8String and contains an NAI extracted from the MN-NAI mobility option included in the received BU message. Alternatively, the NAI can be extracted from the IKEv2 IDi payload included in the IKE_AUTH message sent by the IKE initiator.

The Service-Selection AVP (AVP Code TBD) is of type UTF8String and contains the name of the service or the external network that the mobility service should be associated with. In the scope of this specification the value can extracted from the IKEv2 IDr payload, if available in the IKE_AUTH message sent by the IKE initiator. Alternatively, if the Mobile IPv6 Authentication Protocol is used, then the Service-Selection AVP contains the string extracted from the Service Selection Mobility Option , if available in the received BU. Future specification may define additional ways to populate the Service-Selection AVP with the required information. The AVP is also available to be used in messages sent from the Diameter server to the Diameter client. For example, if the request message did not contain the Service-Selection AVP but the MN was assigned with a default service, the Diameter server MAY return the name of the assigned default service to the HA. If the Service-Selection AVP is present in both the request and the reply messages, it SHOULD contain the same service name. If the services differ, the HA MAY treat that as authorization failure.

The MIP-MN-AAA-SPI AVP (AVP Code 341) is of type Unsigned32 and contains an SPI code extracted from the Mobility Message Authentication Option included in the received BU message. This AVP is re-used from . When the MIP6-Auth-Mode AVP is set to value MIP6_AUTH_MN_AAA, this AVP MUST be present in the MIR message.

The MIP-MN-HA-SPI AVP (AVP Code TBD) is of type Unsigned32 and contains an SPI value that can be used with other parameters for identifying the security association required for the validation of the Mobile IPv6 MN-HA Authentication Option. When the MIP6-Auth-Mode AVP is set to value MIP6_AUTH_MN_AAA, and the Diameter server returns a valid MIP-MN-HA-MSA AVP in the MIA message, this AVP MUST be present inside the MIP-MN-HA-MSA AVP.

The MIP-Mobile-Node-Address AVP (AVP Code 333) is of type Address and contains the HA assigned IPv6 or IPv4 Home Address of the Mobile Node. If the MIP-Mobile-Node-Address AVP contains the unspecified IPv6 address (0::0) or the all zeroes IPv4 address (0.0.0.0) in a request message, then the HA expects the Diameter server to assign the Home Address in a subsequent answer message. If the Diameter server assigns only an IPv6 Home Network Prefix to the Mobile Node the lower 64 bits of the MIP-Mobile-Node-Address AVP provided address MUST be set to zero. This AVP is re-used from .

The MIP6-Agent-Info AVP (AVP Code 486) is defined in Section 4.2.1 of and contains the IPv6 or the IPv4 address information of the HA. The HA address in a request message is the same as in the received BU message that triggered the authentication and authorization procedure towards the Diameter server. One use case is e.g., to inform the Diameter server of the dynamically assigned HA. If the MIP6-Agent-Info AVP is present in an answer message and the Result-Code AVP is set to DIAMETER_SUCCESS_RELOCATE_HA, then the Diameter server is indicating to the HA that it MUST initiate a HA switch procedure towards the MN (e.g., using the procedure defined in ). If the Result-Code AVP is set to any other value, then the HA SHOULD initiate the HA switch procedure towards the MN. The address information of the assigned HA is defined in the MIP6-Agent-Info AVP.

The MIP-Careof-Address AVP (AVP Code TBD) is of type Address and contains the IPv6 or the IPv4 Care-of Address of the Mobile Node. The HA extracts this IP address from the received BU message.

The MIP-Authenticator AVP (AVP Code TBD) is of type OctetString and contains the Authenticator Data from the received BU message. The HA extracts this data from the MN-AAA Mobility Message Authentication Option included in the received BU message. When the MIP6-Auth-Mode AVP is set to value MIP6_AUTH_MN_AAA, this AVP MUST be present in the MIR message.

The MIP-MAC-Mobility-Data AVP (AVP Code TBD) is of type OctetString and contains the MAC_Mobility_Data calculated by the HA as defined in for the MN-AAA Mobility Message Authentication Option. When the MIP6-Auth-Mode AVP is set to value MIP6_AUTH_MN_AAA, this AVP MUST be present in the MIR message.

The MIP-Session-Key AVP (AVP Code 343) is of type OctetString and contains the MN-HA shared secret (i.e., the session key) for the associated Mobile IPv6 MH-HA authentication option. When the Diameter server computes the session key it is placed in this AVP. How the Diameter server computes the session key is not defined in this specification. The Session key derivation is deployment specific and needs to be defines in a respective deployment specific system specification. This AVP is re-used from .

The MIP-MSA-Lifetime AVP (AVP Code 367) is of type Unsigned32 and represents the period of time (in seconds) for which the session key (see ) is valid. The associated session key MUST NOT be used if the lifetime has expired. This AVP is re-used from .

The MIP-MN-HA-MSA AVP (AVP Code TBD) is of type Grouped and contains the session related information for use with the Mobile IPv6 Authentication Protocol.

{ MIP-Session-Key } { MIP-MSA-Lifetime } [ MIP-MN-HA-SPI ] [ MIP-Algorithm-Type ] [ MIP-Replay-Mode ] * [ AVP ] ]]> The MIP-MN-HA-SPI sub-AVP within the MIP-MN-HA-MSA grouped AVP identifies the security association required for the validation of the Mobile IPv6 MN-HA Authentication Option. The absence of the MIP-Replay-Mode AVP MUST be treated as no replay protection was selected.

The MIP-Algorithm-Type AVP (AVP Code 345) is of type Enumerated and contains Algorithm identifier for the associated Mobile IPv6 MN-HA Authentication Option. The Diameter server selects the algorithm type. Existing algorithm types are defined in that also fulfill current RFC 4285 requirements. This AVP is re-used from . When the MIP6-Auth-Mode AVP is set to value MIP6_AUTH_MN_AAA, and the Diameter server returns a valid MIP-MN-HA-MSA AVP in the MIA message, this AVP MUST be present inside the MIP-MN-HA-MSA AVP.

The MIP-Replay-Mode AVP (AVP Code 346) is of type Enumerated and contains the replay mode the HA for authenticating the mobile node. Out of all possible replay modes defined in , the following are supported by this specification:

This AVP is re-used from .

The MIP6-Feature-Vector AVP (AVP Code 124) is defined in . However, this specification does not define any Mobile IPv6 split scenario bootstrapping specific capability flag.

The MIP-Timestamp AVP (AVP Code TBD) is of type OctetString and contains eight octets timestamp value (i.e. 64 bits timestamp) from the Mobility message replay protection option, defined in . The HA extracts this value from the received BU message, if available. The HA includes this AVP in the MIR message when the MN-AAA Mobility Message Authentication Option is available in the received BU and the Diameter server is expected to return the key material required for the calculation and validation of the Mobile IPv6 MN-HA Authentication Option (and the MIP6-Auth-Mode AVP is set to value MIP6_AUTH_MN_AAA).

The QoS-Capability AVP is defined in and contains a list of supported Quality of Service profiles.

The QoS-Resources AVP is defined in and provides QoS and packet filtering capabilities.

The Chargeable-User-Identity AVP (AVP code 89) is of type OctetString and contains an unique temporary handle of the user. The Chargeable-User-Identity is defined in .

The MIP6-Auth-Mode (AVP Code TBD) is of type Enumerated and contains information of the used Mobile IPv6 Authentication Protocol mode. This specification defines only one value MIP6_AUTH_MN_AAA and the corresponding AAA interactions when MN-AAA security association is used to authenticate the Binding Update as described in . When the MIP6-Auth_Mode AVP is set to the value of MIP6_AUTH_MN_AAA, the Auth-Request-Type AVP MUST be set to the value of AUTHORIZE_AUTHENTICATE. If the Diameter server does not support the Mobile IPv6 Authentication Protocol usage mode proposed by the HA, then the Diameter server MUST fail the authentication/authorization and MUST set the Result-Code AVP to the value of DIAMETER_ERROR_AUTH_MODE.

Diameter Mobile IPv6 applications, either MIP6I or MIP6A, are used in the case of the coupled account model. Diameter Mobile IPv4 application accounting AVPs are reused in this document. The following AVPs SHOULD be included in the accounting request message: Accounting-Input-Octets: Number of octets in IP packets received from the mobile node. Accounting-Output-Octets: Number of octets in IP packets sent by the mobile node Accounting-Input-Packets: Number of IP packets received from the mobile node. Accounting-Output-Packets: Number of IP packets sent by the mobile node. Acct-Multi-Session-Id: Used to link together multiple related accounting sessions, where each session would have a unique Session-Id, but the same Acct-Multi-Session-Id AVP. Acct-Session-Time: Indicates the length of the current session in seconds. MIP6-Feature-Vector: The supported features for this mobility service session. MIP-Mobile-Node-Address: The Home Address of the mobile node. MIP-Agent-Info: The current home agent of the mobile node. Chargeable-User-Identity: The unique temporary identity of the user. This AVP MUST be included if it is available in the home agent. Service-Selection: Currently selected mobility service. QoS-Resources: Assigned QoS resources for the mobile node. QoS-Capability: The QoS capability related to the assigned QoS-Resources. MIP-Careof-Address: The current Care-of Address of the mobile node.

This section defines new Result-Code values that MUST be supported by all Diameter implementations that conform to this specification.

Errors that fall within the Success category are used to inform a peer that a request has been successfully completed. This result code is used by the Diameter server to inform the HA that the MN MUST be switched to another HA.

Errors that fall within the permanent failures category are used to inform the peer that the request failed and SHOULD NOT be attempted again. This error code is used by the Diameter server to inform the peer that the requested Mobile IPv6 Authentication Protocol usage mode is not supported.

The following tables present the AVPs defined in this document and their occurrences in Diameter messages. Note that AVPs that can only be present within a Grouped AVP are not represented in this table. The table uses the following symbols: The AVP MUST NOT be present in the message. Zero or more instances of the AVP MAY be present in the message. Zero or one instance of the AVP MAY be present in the message. One instance of the AVP MUST be present in the message.

The table in this section is used to represent which AVPs defined in this document are to be present in the Accounting messages, as defined in .

This section contains the namespaces that have either been created in this specification or had their values assigned to existing namespaces managed by IANA.

IANA is requested to allocate a command code value for the following new commands from the Command Code namespace defined in . See for the assignment of the namespace in this specification.

This specification requires IANA to register the following new AVPs from the AVP Code namespace defined in . MIP-Careof-Address MIP-Authenticator MIP-MAC-Mobility-Data MIP-Timestamp MIP-MN-HA-SPI MIP-MN-HA-MSA Service-Selection MIP6-Auth-Mode The AVPs are defined in .

This specification requests IANA to allocate new values to the Result-Code AVP (AVP Code 268) namespace defined in . See for the assignment of the namespace in this specification.

This specification requires IANA to allocate two new values "Diameter Mobile IPv6 IKE" and "Diameter Mobile IPv6 Auth" from the Application Identifier namespace defined in .

IANA is requested to create a new registry "MIP6 Authentication Mode" registry for use with the enumerated MIP6-Auth-Mode AVP. The registry will initially contain the following value:

Allocation of new values follow the example policies described in new values for the MIP6-Auth-Mode AVP will be assigned based on the "Specification Required" policy. The value 0 (zero) is reserved and the maximum value is 4294967295 (i.e. 2^32-1).

The security considerations for the Diameter interaction required to accomplish the split scenario are described in . Additionally, the security considerations of the Diameter Base protocol , Diameter EAP application are applicable to this document. The Diameter messages may be transported between the HA and the Diameter server via one or more AAA brokers or Diameter agents. In this case the HA to the Diameter server AAA communication rely on the security properties of the intermediating AAA inter-connection networks, AAA brokers and Diameter agents (such as proxies). In case of the Authentication Protocol for Mobile IPv6 , this specification expects that the Diameter server derives the MN-HA Security Association and returns the associated session key (i.e. the MN-HA shared session key) to the HA. However, this specification does not define nor other IETF specification defines how the Diameter server actually derives required keys. The details of the key derivation depends on the deployment where this specification is used and therefore the security properties of the system depend on how this is done.

The authors would like to thank Jari Arkko, Tolga Asversen, Pasi Eronen, Santiago Zapata Hernandez, Anders Kristensen, Avi Lior, John Loughney, Ahmad Muhanna, Behcet Sarikaya, Basavaraj Patil, Vijay Devarapalli, Lionel Morand, Domagoj Premec, Semyon Mizikovsky and Yoshihiro Ohba for all the useful discussions. Ahmad Muhanna provided a detailed review of the document in August 2007. Pasi Eronen provided detailed comments and text proposals during the IESG review that helped to improved this document greatly. We would also like to thank our Area Director, Dan Romascanu, for his support. Hannes Tschofenig would like to thank the European Commission support in the co-funding of the ENABLE project, where this work is partly being developed. Julien Bournelle would like to thank GET/INT since he began this work while he was under their employ. Madjid Nakhjiri would like to thank Huawei USA as most of his contributions to this draft were possible while he was under their employ.