Network Working Group Maria-Carmen Belinchon INTERNET-DRAFT Miguel-Angel Pallares Category: Standards Track Carolina Canales Expires: August 2003 Miguel Garcia Ericsson Peter J. McCann Lucent Jaakko Rajaniemi Kalle Tammi Nokia February, 2003 Diameter Multimedia Application Status of this memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or cite them other than as "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/lid-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This document is an individual submission to the IETF. Comments should be directed to the authors. Abstract This document specifies a Diameter application that supports the authentication, authorization, and collection of accounting information for Session Initiation Protocol (SIP) services rendered to a client node. This application, combined with the base Diameter protocol and appropriate SIP extensions, allows SIP User Agents (UAs) to obtain services from SIP servers that are connected to a Diameter Belinchon et all [Page 1] INTERNET-DRAFT Diameter Multimedia Application February, 2003 infrastructure. When combined with the Inter-Domain capability of the base protocol, service may even be obtained from SIP servers that belong to foreign domains, as would be encountered by roaming mobile nodes. Note that the specification defined here may be used independently of the authentication technique used for authenticating a node's link layer or network-layer access. In particular, we do not require the client node to be authenticated for access with the use of either the Mobile IP [3] or NASREQ [11] Diameter application. TABLE OF CONTENTS 1. Introduction.....................................................3 1.1 Requirements language...........................................4 1.2 Advertising Application Support.................................4 1.3 Definitions.....................................................5 2. Description of a SIP network architecture........................5 2.1 User authentication by SSP......................................6 2.2 User authentication by AAA server...............................8 2.3 Invitation......................................................9 2.4 User Profile Updating..........................................10 2.5 User registration termination..................................10 3 Multimedia messages.............................................11 3.1 User-Authorization-Request (UAR) Command.......................11 3.2 User-Authorization-Answer (UAA) Command........................12 3.3 Server-Assignment-Request (SAR) Command........................14 3.4 Server-Assignment-Answer (SAA) Command.........................15 3.5 Location-Info-Request (LIR) Command............................17 3.6 Location-Info-Answer (LIA) Command.............................17 3.7 Multimedia-Auth-Request (MAR) Command..........................18 3.8 Multimedia-Auth-Answer (MAA) Command...........................19 3.9 Registration-Termination-Request (RTR) Command.................21 3.10 Registration-Termination-Answer (RTA) Command.................21 3.11 Push-Profile-Request (PPR) Command............................22 3.12 Push-Profile-Answer (PPA) Command.............................23 4 Result Code AVP values...........................................24 4.1 Success........................................................24 4.2 Permanent failures.............................................24 5 Diameter AVP values..............................................25 5.1 Charging-Information AVP.......................................27 5.1.1 Primary-Event-Charging-Function-Name AVP.....................27 5.1.2 Secondary -Event-Charging-Function-Name AVP..................27 5.1.3 Primary-Charging-Collection-Function-Name AVP................27 5.1.4 Secondary -Charging-Collection-Function-Name AVP.............27 5.4 Server-Name AVP................................................27 5.5 Server-Capability AVP..........................................28 5.5.1 Mandatory-Capability AVP.....................................28 5.5.2 Optional-Capability AVP......................................28 Belinchon et all [Page 2] INTERNET-DRAFT Diameter Multimedia Application February, 2003 5.6 Server-Assignment-Type AVP.....................................28 5.7 SIP-Auth-Data-Item AVP.........................................29 5.7.1 SIP-Item-Number AVP..........................................30 5.7.2 SIP-Authentication-Scheme AVP................................30 5.7.3 SIP-Authenticate AVP.........................................30 5.7.4 SIP-Authorization AVP........................................30 5.7.5 SIP-Authentication-Info AVP..................................30 5.7.6 SIP-Authentication-Context AVP...............................30 5.7.7 Confidentiality-Key AVP......................................31 5.7.8 Integrity-Key AVP............................................31 5.8 SIP-Number-Auth-Items AVP......................................31 5.9 Deregistration-Reason AVP......................................31 5.9.1 Reason-Code AVP..............................................31 5.9.2 Reason-Info AVP..............................................31 5.10 Public-Identity AVP...........................................32 5.11 Visited-Network-Identifier AVP................................32 5.12 User-Authorization-Type AVP...................................32 5.13 User-Data AVP.................................................32 5.14 User-Data-Already-Available AVP...............................33 5.15 User-Data-Request-Type AVP....................................33 6. Authentication Details..........................................33 7. IANA Considerations.............................................34 8 Acknowledgements.................................................34 9 References.......................................................34 9.1 Normative References...........................................34 9.2 Non-Normative References.......................................35 10 Authors' Addresses..............................................35 11. Full Copyright Statement.......................................36 1. Introduction This document specifies a Diameter application that supports the authentication, authorization and collection of accounting information for SIP-based IP multimedia services rendered to a client node. We assume that a client node implements a SIP User Agent (UA) that carries out SIP protocol actions with a SIP server, which in turn relies on the AAA infrastructure for authenticating the client, authorizing it for particular SIP services, and accounting for this usage. SIP servers can be proxy, redirect, registration, or user agent servers. Additionally, SIP servers may be arranged in arbitrary ways according to the inter-service provider relationships involved in servicing a given client. For example, a mobile node may use a SIP proxy in the visited network, but its SIP messages may be proxied back to a SIP server in the home network that implements call control features. Combined with the Inter-Domain capability of the base Belinchon et all [Page 3] INTERNET-DRAFT Diameter Multimedia Application February, 2003 protocol, this extension would allow such mobile terminals to receive service from foreign service providers according to their location and subscription profile. Any or all of the SIP servers may need to independently authenticate the client, authorize service, and account for usage. Authentication must take place at the time the user agent registers with the SIP server (or chain of SIP proxies and servers) or at any other moment agreed by the entities involved in the authentication (e.g., at SIP session initiation). The particular algorithm used to authenticate a SIP user agent client is a matter of policy agreement between the user agent client, the SIP server, and the home AAA server. This document supports the WWW-Authenticate methods Basic and Digest, which are supported by SIP. In addition to authenticating the user agent client, such a method could also be used to generate or distribute keys for subsequent SIP-layer message integrity and privacy. The specification of such an algorithm, and its embedding in SIP, is outside the scope of this document. Authorization for SIP services may take many forms. For example, a proxy may need to know that the user agent client is authorized to register, but from then on it may simply pass messages through to other SIP servers. However, a SIP server that implements call control features may need a richer and more complete description of the services to which the user has subscribed. Accounting for SIP services is on a per-call basis. An accounting record contains a SIP Call-ID, any SDP that was exchanged to set up the call, the duration of the call, and any resources that were consumed on behalf of the call (such as number of bytes exchanged between the parties). Note that accounting for resources may require the SIP server to interact with other network entities, such as media gateways, for the collection of this information. Such interaction is outside the scope of this document. Some example scenarios, inspired by the emerging wireless applications of SIP, are given in Section 2. Sections 3, 4 and 5 address the Diameter Multimedia Application's specific commands, result codes, and AVPs, respectively. Section 7 gives IANA considerations. 1.1 Requirements language In this document, the key words "MAY", "MUST, "MUST NOT", "optional", "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as described in [10]. 1.2 Advertising Application Support Diameter nodes conforming to this specification MAY advertise support by including the Auth-Application-Id AVP in the Capabilities- Exchange-Request and Capabilities-Exchange-Answer commands [BASE]. Belinchon et all [Page 4] INTERNET-DRAFT Diameter Multimedia Application February, 2003 1.3 Definitions Further clarification of these definitions can be found in ref [10]. Implicit registration: Mechanism that supports for multimedia the registration of a set of public identities belonging to the same group by the registration of only one of the identities. Non-Registered identity: Public multimedia identity that is not registered and for which no data are stored in the network nodes. Registered identity: Public multimedia identity that is registered and therefore the concerned user profile is stored both in the AAA and the SSP. Unregistered identity: Public multimedia identity that is not registered but whose profile is stored either in the AAA server or in the SSP as a consequence of previous registrations or a call in course. 2. Description of a SIP network architecture Home Realm +-------+ UAR/UAA +-->| AAA |<--+ PPR/PPA LIR/LIA | |xyz.com| | MAR/MAA | | | | SAR/SAA | +-------+ | RTR/RTA Local Realm v v +-------+ +-------+ +-------+ | OSP |<----------->| HSP |<----->| SSP | |abc.com| SIP |xyz.com| SIP |xyz.com| +-------+ +-------+ +-------+ ^ ^ | SIP | v | +-------+ SIP | | UAE |<----------------+ +-------+ bob@xyz.com Figure 1: SIP network infrastructure Figure 1 above illustrates the nodes involved in a SIP multimedia network architecture, according to the requirements in [1] and [10]. The home realm (xyz.com) is comprised of a Diameter AAA server, at least one home entry SIP proxy (HSP) which is the gateway SIP proxy seen by the rest of the world, and any number of serving SIP proxy Belinchon et all [Page 5] INTERNET-DRAFT Diameter Multimedia Application February, 2003 (SSP) nodes. These SSP nodes may be deployed piecemeal for various reasons such as but not limited to load balancing, scalability, and offering distinct, separate services. The mobile node in this scenario (bob@xyz.com) may either connect directly to its HSP, or via an outbound SIP server (OSP) in the local realm. In larger networks, registrations MAY be routed to different HSPs, potentially even for a subsequent SIP registration for the same user, and thus HSPs are usually stateless. The next few sections will describe in detail the different modes of operation that are available to such an infrastructure. These options may be either administratively configured to suit local policies, or determined dynamically by the network. For the purposes of authentication and authorization, the procedures involved when using a OSP are a superset of the procedures involved in the absence of a OSP, and therefore we will skip a needless explanation of the latter scenario. 2.1 User authentication by SSP An operator with a large base of installed SIP servers may wish to minimize the impact of modifying SIP servers to interact with Diameter AAA servers. This can be achieved by allowing SIP servers to retain the functionality of authentication, rather than exporting this capability to the AAA server. However, it should be noted that this mode will not leverage the extensive array of authentication and authorization services which will already be present regardless in diameter servers. Below follows an example of a SIP user registration using the SSP authentication mode. +-------+ +-------+ +-------+ | HSP | | AAA | | SSP | +---+---+ +---+---+ +---+---+ | | | 1. SIP-REG | | | ---------->| 2. UAR | | +------------------>| | | 3. UAA | | |<------------------+ | | 4. SIP-REG | | +-------------------------------------->| | | 5. MAR | | |<------------------+ | | 6. MAA | | +------------------>| | 7. 401 (Unauthorized) | 8. 401 |<--------------------------------------+ <-----------+ | | 9. SIP-REG | | | Belinchon et all [Page 6] INTERNET-DRAFT Diameter Multimedia Application February, 2003 ---------->| 10. UAR | | +------------------>| | | 11. UAA | | |<------------------+ | | | 12. SIP-REG | +-------------------------------------->| | | 13. SAR | | |<------------------+ | | 14. SAA | | +------------------>| | 15. 200 (OK) | | 16. 200 |<--------------------------------------+ <-----------+ | | | | | Figure 2: Authentication performed by the SSP In this scenario, a user sends a SIP registration to the home domain. The HSP will contact its local diameter server with a "User- Authorization-Request" (UAR) to authorize if this user is allowed to receive service, and if so, request the identity of a local SIP server capable of handling this user. The diameter server will respond with a "User-Authorization-Answer" (UAA), which will inform about the result of the user authorization. In case of a successful authorization, the UAA will indicate either the identity of a local SIP server or a list of capabilities from which the HSP will select the appropriate SSP. When successful authorization, the HSP will forward the registration request to the appropriate SSP. The SSP will then request authentication parameters from the diameter server through a "Multimedia-Auth-Request" (MAR). This request MAY also serve to identify the SSP, so as to return subsequent registration requests of the same user to the same SSP. The diameter server will respond with a "Multimedia-Auth-Answer" (MAA), which will include all parameters necessary for the designated authentication algorithm associated with the user. The SSP will then create the 401 (Unauthorized) message, including the authentication material needed by the mobile user to prove his/her identity. When the subsequent SIP registration is received from the user, the HSP (assumed to be stateless) will once again contact the diameter server with a UAR to determine to which SSP to forward the registration. The HSP will then forward the SIP registration to the SSP node. The SSP node performed the authentication in the previous registration request by means of MAR/MAA, so at this point it is not necessary to ask for it again. Instead, the SSP will contact the AAA server by means of a Server-Assignment-Request (SAR) requesting it to store the name of the server that is currently serving the user and the concerned user profile. Belinchon et all [Page 7] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The AAA server will respond with a "Server-Assignment-Answer" (SAA). If the Result-Code does not inform about an error, the User-Data AVP shall contain the information that the SSP needs to give service to the user. The SSP will produce then a 200 (OK) message, and send it to the HSP. The HSP will then forward the 200 (OK) message towards the mobile user. 2.2 User authentication by AAA server A different approach in deploying SIP networks is to allow the Diameter server to perform the actual authentication. In addition to leveraging the robust authentication services offered by the AAA server, it will reduce the number of messages sent in the network. +-------+ +-------+ +-------+ | HSP | | AAA | | SSP | +---+---+ +---+---+ +---+---+ | | | 1. SIP-REG | | | ---------->| 2. UAR | | +------------------>| | | 3. UAA | | |<------------------+ | | | 4. SIP-REG | +-------------------------------------->| | | 5. MAR | | |<------------------+ | | 6. MAA | | +------------------>| | 7. 401 (Unauthorized) | 8. 401 |<--------------------------------------+ <-----------+ | | 9. SIP-REG | | | ---------->| 10. UAR | | +------------------>| | | 11. UAA | | |<------------------+ | | | 12. SIP-REG | +-------------------------------------->| | | 13. MAR | | |<------------------+ | | 14. MAA | | +------------------>| | 15. 200 (OK) | | 16. 200 |<--------------------------------------+ <-----------+ | | | | | Belinchon et all [Page 8] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Figure 3: Authentication performed by the AAA server In this scenario, the user will send a SIP register message to it's home domain. When the HSP receives this request, it will contact its local diameter server with a "User-Authorization-Request" (UAR) to determine if this user is allowed to receive service and if so, request the identity of a local SIP server capable of handling this user, as described in the previous section. The diameter server will respond with a "User-Authorization-Answer" (UAA), which will indicate a list of capabilities from which the HSP will use to select the SSP. Once it forwards the initial SIP registration to the appropriate SSP, the SSP will then request user authentication from the Diameter server through a "Multimedia-Auth-Request" (MAR). This request MAY also serve to identify the SSP, so as to return subsequent registration requests to the same SSP. The Diameter server will then respond with a "Multimedia-Auth-Answer" (MAA) with Result-Code equal to DIAMETER_MULTI_ROUND_AUTH and the challenge information, which the SSP will use to map into the WWW-authentication header in the SIP 401 unauthorized and send back to the HSP. When the subsequent SIP registration is received from the user, the HSP will once again contact the diameter server with a UAR to determine to which SSP to forward the registration. The HSP will then forward the SIP registration to the SSP node, which will then extract the relevant authentication parameters, and include these in a MAR message to the AAA server. This request MAY also serve to identify the SSP, so as to return subsequent registration requests to the same SSP. At this point, the Diameter server will be able to authenticate the user, and upon success, will return a MAA with Result-Code equal to DIAMETER_SUCCESS and include user profile information, which the SSP will use to give service to the user, the SSP will then produce a 200 (OK) message and send it to the HSP, which will then forward it to the mobile user. 2.3 Invitation When a registered user wishes to invite another registered user, it will send a SIP Invite request to the home domain (HSP) of the invitee. +-------+ +-------+ +-------+ | HSP | | AAA | | SSP | +---+---+ +---+---+ +---+---+ | | | 1. SIP-INV | | | ---------->| 2. LIR | | +------------------>| | | 3. LIA | | Belinchon et all [Page 9] INTERNET-DRAFT Diameter Multimedia Application February, 2003 |<------------------+ | | | 4. SIP-INV | +-------------------------------------->| | | | Figure 5. A SIP Invite request In this scenario, when a user, say Bob, contacts the HSP to invite another user, say Mary, the MaryĘs HSP will issue a diameter "Location-Info- Request" (LIR) message to the AAA server to request the identity of the SSP currently assigned to Mary. The AAA server will respond with a diameter "Location-Info-Answer" (LIA), indicating the appropriate SSP, and the HSP will forward the SIP Invite message directly to the named SSP. 2.4 User Profile Updating Whenever a modification in the user profile has occurred, the AAA server and SSP must synchronize their user profile data. +-------+ +-------+ | AAA | | SSP | +---+---+ +---+---+ | | | 1. PPR | +------------------>| | | | 2. PPA | |<------------------+ | | Figure 6. User profile update initiated by AAA server The AAA server sends a Push-Profile-Request (PPR) to the serving SIP server to which the user is registered. The PPR message contains a User-Data AVP with the updated user profile. 2.5 User registration termination Termination of an entire user registration can be achieved by one of two mechanisms. In the event that NO_STATE_MAINTAINED (i.e NO Diameter user session-id is maintained) has been indicated in a prior Auth-Session-State AVP, termination is handled with a Session- Termination-Request (if it is initiated by the SSP/HSP) or with a Registration-Termination-Request (if it is initiated by the AAA). On the other hand, if STATE_MAINTAINED has been indicated in a prior Auth-Session-State AVP, the use of Session-Termination-Request (STR) and Abort-Session-Request (ASR) messages as defined in the base protocol are used to terminate an entire user registration. Belinchon et all [Page 10] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Reasons for terminating a user registration could be due to the expiration of the SIP registration timer in the SIP server, a user initiated SIP de-registration, or a AAA-initiated de-registration as a result of administrative reasons. 3 Multimedia messages This section defines new Diameter message Command-Code [8] values that MUST be supported by all Diameter implementations that conform to this specification. The Command Codes (assigned by IANA in ref [8]) are: Command-Name Abbrev. Code Reference ------------------------------------------------------------------ User-Authorization-Request UAR 300 3.1 User-Authorization-Answer UAA 300 3.2 Server-Assignment-Request SAR 301 3.3 Server-Assignment-Answer SAA 301 3.4 Location-Info-Request LIR 302 3.5 Location-Info-Answer LIA 302 3.6 Multimedia-Auth-Request MAR 303 3.7 Multimedia-Auth-Answer MAA 303 3.8 Registration-Termination-Request RTR 304 3.9 Registration-Termination-Answer RTA 304 3.10 Push-Profile-Request PPR 305 3.11 Push-Profile-Answer PPA 305 3.12 3.1 User-Authorization-Request (UAR) Command The User-Authorization-Request (UAR), indicated by the Command-Code field set to 300 and the 'R' bit set in the Command Flags field, is sent by an HSP node, acting as a Diameter client, to a AAA server in order to request authorization of a mobile user. The HSP asks for authorization of the REGISTRATION, DE-REGISTRATION or REGISTRATION&CAPABILITIES procedure to the AAA server. For the exact meaning of these values, see User-Authorization-Type AVP (chapter 5.12). According to [10], a user is defined in the multimedia system by one private identity and one or more public identities. Both of them are checked in the registration process. The HSP extracts the private identity from the SIP Authorization: header and includes it in the UAR message within the User-Name AVP. The HSP extracts the public identity from the SIP From: header and includes it in the UAR message within the Public-Identity AVP. Belinchon et all [Page 11] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Message Format < User-Authorization-Request > ::= Diameter Header: 300: REQ, PXY > < Session-ID > < Auth-Application-Id > { Auth-Session-State } { Origin-Host } { Origin-Realm } [ Destination-Host ] { Destination-Realm } { User-Name } { Public-Identity } { Visited-Network-Identifier } [ User-Authorization-Type ] * [ AVP ] * [ Proxy-Info ] * [ Route-Record ] 3.2 User-Authorization-Answer (UAA) Command The User-Authorization-Answer (UAA), indicated by the Command-Code field set to 300 and the 'R' bit cleared in the Command Flags field, is sent by a AAA server in response to the User-Authorization-Request command. The Result-Code AVP may contain one of the values defined in section 4 in addition to the values already defined in [2]. Whenever a failure is encountered, the AAA will stop processing and return the concerned error. When no error code is specified, the AAA will set the code to DIAMETER_SUCCESS. When the authorization procedure succeeds, the AAA server sends back to the HSP the name of an already assigned SSP or the capabilities needed by the HSP to select the appropriate SSP. The UAA message will carry one information or the other based on the received User- Authorization-Type AVP value and the public identity. At reception of the UAR message, the AAA server MUST check the existence of the user (i.e., the private identity is defined). If the server does not recognized the user private identity received in the User-Name AVP, the DIAMETER_ERROR_USER_UNKNOWN code will be sent back to the HSP. Otherwise the AAA will check that this private identity matches with the public identity received in the Public-Identity AVP. If there is no match, the AAA server will send back to the HSP the DIAMETER_ERROR_IDENTITIES_DONT_MATCH code. If no error occurred, the AAA server MUST check that the user is allowed to roam in the visited network and is authorized to register. This is performed only if the received User-Authorization-Type AVP value is equal to REGISTRATION or REGISTRATION&CAPABILITIES. In case of failure, the AAA server will send back to the HSP the Belinchon et all [Page 12] INTERNET-DRAFT Diameter Multimedia Application February, 2003 DIAMETER_ERROR_ROAMING_NOT_ALLOWED or DIAMETER_AUTHORIZATION_REJECTED code. In the case that the requested authorization type was REGISTRATION&CAPABILITIES, the AAA will send back the needed capabilities for the HSP to select an appropriate SSP. The UAA will make use of the Server-Capabilities AVP to convey this information. In the case that the authorization type was REGISTRATION: - If the user (i.e., that public identity or other implicitly registered identity) has been already authorized (registered), the Result-Code AVP is set to DIAMETER_SUBSEQUENT_REGISTRATION and the UAA will make use of the Server-Name AVP to contain the SIP URL of the currently assigned server - If the user is unregistered, i.e. there is no any registered identity but at least one identity is unregistered, a server is already assigned for that user, the Result-Code AVP is set to DIAMETER_SUBSEQUENT_REGISTRATION if the AAA knows that no server needs to be re-assigned, and the UAA will make use of the Server- Name AVP to contain the SIP URL of the currently assigned server. Otherwise, the Result-Code AVP is set to DIAMETER_SERVER_SELECTION and either the capabilities and the already assigned server name is sent back to let the HSP to decide whether or not selecting a new server. - If the user is unregistered, i.e. there is no registered or unregistered identity, the Result-Code AVP is set to DIAMETER_FIRST_REGISTRATION and the UAA will make use of the Server-Capabilities AVP to convey the information needed by the HSP to select an appropriate SSP. In the case that the authorization type was DE-REGISTRATION: - If the user (i.e., that public identity or other implicitly registered identity) has been already authorized (registered), the Result-Code AVP is set to DIAMETER_SUCESS and the AAA removes the information for that identity (or set of identities when they are implicitly registered). - If the user is unregistered, i.e. there is no any registered identity but at least one identity is unregistered, a server is already assigned for that user, so the Result-Code AVP is set to DIAMETER_SUCESS and the AAA removes the information for that identity (or set of identities when they are implicitly registered). - If the user is unregistered, i.e. there is no registered or unregistered identity, the Result-Code AVP is set to DIAMETER_ERROR_IDENTITY_NOT_REGISTERED. Belinchon et all [Page 13] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Message Format < User-Authorization-Answer > ::= < Diameter Header: 300: PXY > < Session-Id > { Auth-Application-Id } { Auth-Session-State } [ Result-Code ] { Origin-Host } { Origin-Realm } [ Server-Name ] [ Server-Capabilities ] [ Authorization-Lifetime ] [ Auth-Grace-Period ] *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.3 Server-Assignment-Request (SAR) Command The Server-Assignment-Request (SAR) command, indicated by the Command-Code field set to 301 and the 'R' bit set in the Command Flags field, is sent by a Diameter Multimedia client to a Diameter Multimedia server to request it to store the name of the server that is currently serving the user. Upon registration procedure, once the user authentication has been performed, the SSP MUST inform the AAA server that he is the SSP serving that user, and at the same time the SSP requests for the user profile. This is done by means if SAR/SAA commands. The SAR/SAA exchange also occurs when an INVITE SIP message is received in the HSP and therefore the SSP is selected for the communication. For other cases where the SAR/SAA procedure is performed, see chapter 5.6 (Server-Assignment-Type AVP). When requesting the user profile, the SSP can request the whole user profile, just the information related to the registered public identities, or the information related to the unregistered (but still in use) identities. This is accomplished by the concerned value in the User-Data-Request-Type and User-Data-Already-Available AVPs. Message Format ::= < Diameter Header: 301, REQ, PXY> < Session-Id > { Auth-Application-Id } { Auth-Session-State } { Origin-Host } { Origin-Realm } Belinchon et all [Page 14] INTERNET-DRAFT Diameter Multimedia Application February, 2003 [ Destination-Host ] { Destination-Realm } [ User-Name ] *[ Public-Identity ] [ Server-Name ] { Server-Assignment-Type } { User-Data-Request-Type } { User-Data-Already-Available} *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.4 Server-Assignment-Answer (SAA) Command The Server-Assignment-Answer (SAA) command, indicated by the Command- Code field set to 301 and the 'R' bit cleared in the Command Flags field, is sent by a server in response to the Server-Assignment- Request command. The Result-Code AVP may contain one of the values defined in section 4 in addition to the values already defined in [2]. If Result-Code does not inform about an error, the User-Data AVP shall contain the information that the SSP needs to give service to the user. At reception of the SAR, the AAA MUST check first that the user exists (i.e., the private identity is defined). If the server does not recognized the user private identity received in the User-Name AVP, the DIAMETER_ERROR_USER_UNKNOWN code will be sent back to the HSP. Otherwise the AAA will check that this private identity matches with the public identity received in the Public-Identity AVP. If there is no match, the AAA server will send back to the HSP the DIAMETER_ERROR_IDENTITIES_DONT_MATCH code. If the SSP contacted the AAA to perform a REGISTRATION or RE_REGISTRATION (Server Assignment Type AVP) procedure, the AAA shall download the relevant user public identity information to the SSP and the Result-Code shall be set to DIAMETER_SUCCESS. At this point, the identity is considered authenticated and registered. Only one identity can be present in the request. If more than one identity is present, the Result-Code shall be set to DIAMETER_AVP_OCCURS_TOO_MANY_TIMES and no user information shall be returned. If the SSP contacted the AAA due to UNREGISTERED_USER, the AAA shall store the SSP name, download the relevant user public identity information and the Result-Code shall be set to DIAMETER_SUCCESS. At this point, the identity is considered unregistered. Only one identity can be present in the request. If more than one identity is present, the Result-Code shall be set to DIAMETER_AVP_OCCURS_TOO_MANY_TIMES and no modifications shall be performed. Belinchon et all [Page 15] INTERNET-DRAFT Diameter Multimedia Application February, 2003 If the SSP contacted the AAA due to TIMEOUT_DEREGISTRATION, USER_DEREGISTRATION, DEREGISTRATION_TOO_MUCH_DATA or ADMINISTRATIVE_DEREGISTRATION, the AAA shall clear the SSP name for all the public identities that the SSP indicated in the request. If no public identity is present in the request, the private identity MUST be present; the AAA shall clear the SSP name for all the identities of the user. At this point, the identities are considered not registered. The Result-Code shall be set to DIAMETER_SUCCESS. If the SSP contacted the AAA due to TIMEOUT_DEREGISTRATION_STORE_SERVER_NAME or USER_DEREGISTRATION_STORE_SERVER_NAME, the AAA decides whether to keep the stored SSP name or not for all the public identities that the SSP indicated in the request. If no public identity is present in the request, the private identity MUST be present and the previous decision applies to all the user public identities. At this point, the identities are considered unregistered. If the AAA decides to keep the SSP name the Result-Code shall be set to DIAMETER_SUCCESS, otherwise shall be set to DIAMETER_SUCCESS_SERVER_NAME_NOT_STORED. If the SSP contacted the AAA due to NO_ASSIGNMENT, the AAA checks whether the user is assigned for the SSP requesting the data and downloads the user public identity information requested in the User- Data-Request-Type AVP. The Result-Code shall be set to DIAMETER_SUCCESS. If the requesting SSP is not the same as the assigned SSP, the Result-Code shall be set to DIAMETER_UNABLE_TO COMPLY. If the SSP contacted the AAA due to AUTHENTICATION_FAILURE or AUTHENTICATION_TIMEOUT, the AAA shall clear the SSP name for the public identity that the SSP indicated in the request and the Result- Code shall be set to DIAMETER_SUCCESS. At this point, the identity is considered unregistered. Only one identity can be present in the request. If more than one identity is present the Result-Code shall be set to DIAMETER_AVP_OCCURS_TOO_MANY_TIMES and no modifications shall be performed. See chapter 4.2 for the description on the behavior of the AAA when the name of the SSP received in the request is different from the name already stored in the AAA. Message Format ::= < Diameter Header: 301: PXY > < Session-Id > { Auth-Application-Id } [ Result-Code ] { Auth-Session-State } { Origin-Host } { Origin-Realm } [ User-Data ] Belinchon et all [Page 16] INTERNET-DRAFT Diameter Multimedia Application February, 2003 [ Charging-Information ] [ Auth-Grace-Period ] [ Authorization-Lifetime ] *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.5 Location-Info-Request (LIR) Command The Location-Info-Request (LIR), indicated by the Command-Code field set to 302 and the 'R' bit set in the Command Flags field, is sent by an HSP node, acting as a Diameter client, to a Diameter server in order to request the identity of SIP server currently associated with a particular user. The HSP queries the AAA server to get the SSP in which the user was registered. The user registration is identified by the public identity. Message Format < Location-Info-Request > ::= < Diameter Header: 302, REQ, PXY > < Session-Id > { Auth-Application-Id } { Auth-Session-State } { Origin-Host } { Origin-Realm } [ Destination-Host ] { Destination-Realm } { Public-Identity } *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.6 Location-Info-Answer (LIA) Command The Location-Info-Answer (LIA), indicated by the Command-Code field set to 302 and the 'R' bit cleared in the Command Flags field, is sent by a Diameter server in response to a Location-Info-Request. At reception of the LIR command, the AAA server will send back to the HSP either the SIP server currently associated with the user or the needed capabilities for the HSP to select an appropriate SSP. The Result-Code AVP may contain one of the values defined in section 4 in addition to the values already defined in [2]. The AAA shall stop processing and return the corresponding error code when a failure is encountered. Otherwise, DIAMETER_SUCCESS Result-Code AVP is returned. Belinchon et all [Page 17] INTERNET-DRAFT Diameter Multimedia Application February, 2003 At reception of the LIR, the AAA MUST check first that the user exists (i.e., the public identity is defined). If the server does not recognized the user public identity received in the Public-Identity AVP, the DIAMETER_ERROR_USER_UNKNOWN code will be sent back to the HSP. Otherwise the registration status of the public identity received in the request is checked. If it is registered or unregistered, the AAA shall return the stored SSP name within the Server-Name AVP and the Result-Code AVP shall be set to DIAMETER_SUCCESS. If it is not registered, but has services related to unregistered state, the AAA may return information about the required SSP capabilities, which enables the HSP to select an SSP. In this case, the Server-Capabilities AVP will be present and with the same information that is sent in the UAR message during the registration. If Server-Capabilities AVP is not present, the HSP will understand that any SSP is suitable to serve the user. The Server-Name AVP will not be present and the Vendor-Specific-Result will be set to DIAMETER_UNREGISTERED_SERVICE. If it is not registered and has no unregistered services related data, the response shall contain the Result-Code AVP set to DIAMETER_ERROR_IDENTITY_NOT_REGISTERED. If the AAA cannot fulfil received request, e.g. due to database error, it shall set Result-Code to DIAMETER_UNABLE_TO_COMPLY. No SSP name or SSP capabilities shall be present in the response. Message Format < Location-Info-Answer > ::= < Diameter Header: 302: PXY > < Session-Id > { Auth-Application-Id } [ Result-Code ] { Auth-Session-State } { Origin-Host } { Origin-Realm } [ Server-Name ] [ Server-Capabilities ] [ Auth-Grace-Period ] [ Authorization-Lifetime ] *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.7 Multimedia-Auth-Request (MAR) Command Belinchon et all [Page 18] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The Multimedia-Auth-Request (MAR), indicated by the Command-Code field set to 303 and the 'R' bit set in the Command Flags field, is sent by an SSP node, acting as a Diameter client, to a server in order to request the authentication of a mobile user. The Diameter client uses information found in the SIP Request to construct the AVPs that are to be included as part of the MAR. Message Format < Multimedia-Auth-Request > ::= < Diameter Header: 303, REQ, PXY > < Session-ID > { Auth-Application-Id } { Auth-Session-State } { Origin-Host } { Origin-Realm } { Destination-Realm } [ Destination-Host ] { User-Name } { Public-Identity } [ SIP-Number-Auth-Items ] [ SIP-Auth-Data-Item ] * [ AVP ] * [ Proxy-Info ] * [ Route-Record ] 3.8 Multimedia-Auth-Answer (MAA) Command The Multimedia-Auth-Answer (MAA), indicated by the Command-Code field set to 303 and the 'R' bit cleared in the Command Flags field, is sent by the server in response to the Multimedia-Auth-Request command. The Result-Code AVP may contain one of the values defined in section 4 in addition to the values defined in [2]. Depending on where the authentication is performed (in the SSP or AAA), the MAR/MAA sequence is performed just after the SSP receives non-integrity protected REGISTER SIP method (authentication to be performed in the SSP) or after the SSP receives a integrity protected REGISTER SIP method (authentication performed in the AAA). At reception of the MAR, the AAA MUST check first that the user exists (i.e., the private identity is defined). If the server does not recognized the user private identity received in the User-Name AVP, the DIAMETER_ERROR_USER_UNKNOWN code will be sent back to the HSP. Otherwise the AAA will check that this private identity matches with the public identity received in the Public-Identity AVP. If there is no match, the AAA server will send back to the HSP the DIAMETER_ERROR_IDENTITIES_DONT_MATCH code. The AAA MUST check that the authentication scheme indicated within the grouped SIP-Auth-Data-Item AVP is supported. If not, the AAA will send back the DIAMETER_ERROR_AUTH_SCHEME_NOT_SUPPORTED code. Belinchon et all [Page 19] INTERNET-DRAFT Diameter Multimedia Application February, 2003 If the received MAR contains the SIP-Authorization and Destination- Host AVPs within the grouped SIP-Auth-Data-Item AVP, the AAA detects that the authorization is being requested after a synchronization failure. In this case, the AAA shall return the requested authentication information and the Result-Code shall be set to DIAMETER_SUCCESS. Otherwise, the AAA shall download as many Authentication-Data-Item grouped AVPs as the number specified in the SIP-Number-Auth-Items AVP from the MAR message. Then, the AAA shall check the registration status of the public identity received in the request. If it is registered or unregistered, and the SSP name received in the MAR is different from the one stored in the AAA, the AAA considers the public identity as pending of the authentication confirmation. The Result-Code shall be set to DIAMETER_SUCCESS. If it is registered or unregistered, and the SSP name received in the MAR is identical to the one stored in the AAA, the Result-Code shall be set to DIAMETER_SUCCESS. If the public identity is unregistered, it is considered as pending of the authentication confirmation. And the AAA shall store the SSP name. . And the AAA shall store the SSP name. If it is not registered, the public identity is considered as pending of the authentication confirmation. The Result-Code shall be set to DIAMETER_SUCCESS. AAA shall treat exceptions to the cases specified here as error situations where the Result-Code shall be set to DIAMETER_UNABLE_TO_COMPLY and no authentication information shall be returned. Message Format < Multimedia-Auth-Answer > ::= < Diameter Header: 303, PXY > < Session-Id > { Auth-Application-Id } [ Result-Code ] { Auth-Session-State } { Origin-Host } { Origin-Realm } [ User-Name ] [ Public-Identity ] [ SIP-Number-Auth-Items ] * [ SIP-Auth-Data-Item ] [ Authorization-Lifetime ] [ Auth-Grace-Period ] * [ AVP ] * [ Proxy-Info ] * [ Route-Record ] Belinchon et all [Page 20] INTERNET-DRAFT Diameter Multimedia Application February, 2003 3.9 Registration-Termination-Request (RTR) Command The Registration-Termination-Request (RTR) command, indicated by the Command-Code field set to 304 and the 'R' bit set in the Command Flags field, is sent by a Diameter Multimedia server to a Diameter Multimedia client in order to request the de-registration of a user. The AAA server can initiate the de-registration of a user and inform the SSP by means of the RTR message. The AAA can decide whether only one public identity is going to be de-registered, a list of public identities, or all the identities of the user (Public-Identity AVP is then not present in the request). The AAA shall also inform the SSP the reason for the de-registration, which will be included in the DeRegistration-Reason AVP. Message Format ::= < Diameter Header: 304, REQ, PXY > < Session-Id > { Auth-Application-Id } { Auth-Session-State } { Origin-Host } { Origin-Realm } { Destination-Host } { Destination-Realm } { User-Name } *[ Public-Identity ] { DeRegistration-Reason } *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.10 Registration-Termination-Answer (RTA) Command The Registration-Termination-Answer (RTA) command, indicated by the Command-Code field set to 304 and the 'R' bit cleared in the Command Flags field, is sent by a client in response to the Registration- Termination-Request command. The Result-Code AVP may contain one of the values defined in section 4 in addition to the values already defined in [2]. At reception of an RTR message, the SSP will proceed to the public identities de-registration. If only one public identity or a list of them was present in the RTR message, the SSP shall remove all the stored information for these identities. If no public identity was included in the request message, the SSP shall remove all information (all public identities) related to the user identified by the private identity. Belinchon et all [Page 21] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The de-registration procedure also implies some other actions for the SSP, who will act based on the Deregistration-Reason AVP. If the reason was PERMANENT_TERMINATION, the IMS subscription or service profile(s) has been permanently terminated. The SSP should start the network initiated de-registration towards the user. If the reason was NEW_SERVER_ASSIGNED, the AAA informs the SSP that a new SSP has been allocated to the user due to some reason. The SSP MUST not start the network initiated de-registration towards the user but only clears its registration state and information regarding the user, i.e. all service profiles are cleared. If the reason was SERVER_CHANGE, the AAA informs the SSP that a new SSP shall be allocated to the user when the user's SSP capabilities are changed in the AAA or when the SSP indicates that it has not enough memory for the updated User Profile. The SSP should start the network initiated de-registration towards the user, i.e. all registrations are de-registered and the user is asked to re-register to all existing registrations. If the reason was REMOVE_SSP, the AAA indicates to the SSP that the SSP should no longer be used for a given user. The SSP shall not start the network initiated de-registration towards the user when the user is not currently registered but clears all information regarding the user and responds to the AAA. The AAA then removes the SSP for that user. Message Format ::= < Diameter Header: 304, PXY > < Session-Id > { Auth-Application-Id } [ Result-Code ] { Auth-Session-State } { Origin-Host } { Origin-Realm } [ Auth-Grace-Period ] [ Authorization-Lifetime ] *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.11 Push-Profile-Request (PPR) Command The Push-Profile-Request (PPR) command, indicated by the Command-Code field set to 305 and the 'R' bit set in the Command Flags field, is sent by a Diameter Multimedia server to a Diameter Multimedia client in order to update the subscription data of a multimedia user in the Belinchon et all [Page 22] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Diameter Multimedia client whenever a modification has occurred in the subscription data that constitutes the data used by the client. The AAA uses this message to notify to the SSP changes in the profile of one of the SSP users. The SSP includes the updated user profile in the User-Data AVP. Message Format < Push-Profile-Request > ::= < Diameter Header: 305, REQ, PXY > < Session-Id > { Auth-Application-Id } { Auth-Session-State } { Origin-Host } { Origin-Realm } { Destination-Host } { Destination-Realm } { User-Name } { User-Data } [ Authorization-Lifetime ] [ Auth-Grace-Period ] *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 3.12 Push-Profile-Answer (PPA) Command The Push-Profile-Answer (PPA) command, indicated by the Command-Code field set to 305 and the 'R' bit cleared in the Command Flags field, is sent by a client in response to the Push-Profile-Request command. The Result-Code AVP may contain one of the values defined in section 4 in addition to the values already defined in [2]. At reception of PPR message, the SSP understands that changes have occurred in the profile of a user and proceeds to update the information. When no error occurs, the SSP shall overwrite the received user profile for all public identities related to the received private identity (User-Name AVP), and shall return DIAMETER_SUCCESS code. When no error occurs, the SSP shall overwrite the received user profile for all public identities indicated within the user data (User-Data AVP), and shall return DIAMETER_SUCCESS code. If the SSP receives an update request for a user not found, the error code DIAMETER_ERROR_USER_UNKNOWN is sent back. If the SSP receives more data than it can accept, it shall return the DIAMETER_ERROR_TOO_MUCH_DATA error code to the AAA. The SSP shall not overwrite the data that it already has to give service to the user Belinchon et all [Page 23] INTERNET-DRAFT Diameter Multimedia Application February, 2003 and the AAA shall initiate a network-initiated de-registration procedure towards the SSP with Deregistration-Reason set to SERVER_CHANGE, which will trigger the assignment of a new SSP. If the request failed for any other reason, the DIAMETER_UNABLE_TO_COMPLY error is sent back. Message Format < Push-Profile-Answer > ::=< Diameter Header: 10415: 305 > < Session-Id > { Auth-Application-Id } [ Result-Code ] { Auth-Session-State } { Origin-Host } { Origin-Realm } *[ AVP ] *[ Proxy-Info ] *[ Route-Record ] 4 Result Code AVP values This section defines new Result codes in addition to the values defined in [2]. 4.1 Success Errors that fall within the Success category are used to inform a peer that a request has been successfully completed. DIAMETER_FIRST_REGISTRATION 2001 The user was not previously registered, and has now been authorized by the AAA server. Information necessary to select an appropriate SSP SHOULD be included in the message. DIAMETER_SUBSEQUENT_REGISTRATION 2002 The user has been previously registered, and has now been re- authorized by the AAA server. The identity of the SSP to which the user is currently registered SHOULD be included in the message. DIAMETER_UNREGISTERED_SERVICE 2003 The user is not currently registered, but the requested service can still be granted to the user. DIAMETER_SUCCESS_SERVER_NAME_NOT_STORED 2004 The HSS informs to the S-CSCF that de-registration was successful but the SSP name is not stored in the AAA. 4.2 Permanent failures Belinchon et all [Page 24] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Errors that fall within the permanent failures category are used to inform the peer that the request failed, and should not be attempted again. DIAMETER_ERROR_USER_UNKOWN 5001 A message was received for a user that is unknown. DIAMETER_ERROR_IDENTITIES_DONT_MATCH 5002 The value in one of the Public-Identity AVPs does not correspond to the private user identity specified in the User-Name AVP. DIAMETER_ERROR_IDENTITY_NOT_REGISTERED (5003) A query for location information is received for a public identity that has not been registered before. The user to which this identity belongs cannot be given service in this situation. DIAMETER_ERROR_ROAMING_NOT_ALLOWED 5004 The user is not allowed to roam in the visited network. DIAMETER_ERROR_IDENTITY_ALREADY_REGISTERED 5005 The identity being registered has already a server assigned and the registration status does not allow that it is overwritten. DIAMETER_ERROR_AUTH_SCHEME_NOT_SUPPORTED 5006 The authentication scheme indicated in an authentication request is not supported. DIAMETER_ERROR_IN_ASSIGNMENT_TYPE 5007 The SSP name sent in the Server-Assignment-Request command is the same SSP name as the assigned SSP name, but Server-Assignment-Type is not allowed, e.g. the user is registered and the SSP sends Server- Assignment-Request indicating the assignment for the unregistered user. DIAMETER_ERROR_TOO_MUCH_DATA 5008 The SSP receives more data than it can accept. The SSP shall not overwrite the data that it already has to give service to the user and the AAA shall initiate a network-initiated de-registration procedure towards the SSP with Deregistration-Reason set to SERVER_CHANGE, which will trigger the assignment of a new SSP DIAMETER_ERROR_NOT SUPPORTED_USER_DATA 5009 The SSP informs AAA that the received subscription data contained information, which was not recognized or supported. 5 Diameter AVP values The following sections define the AVPs used in this diameter application. Belinchon et all [Page 25] INTERNET-DRAFT Diameter Multimedia Application February, 2003 +---------------------+ | AVP Flag rules | |----+-----+----+-----|----+ AVP Section | | |SHLD| MUST|MAY | Attribute Name Code Defined Data Type |MUST| MAY | NOT| NOT|Encr| -----------------------------------------|----+-----+----+-----|----| Visited- 1 5.11 OctectString | | | | | N | Network-Identifier | | | | | | Public- 2 5.10 UTF8String | | | | | N | Identity | | | | | | Server-Name 3 5.4 UTF8String | | | | | N | Server 4 5.5 Grouped | | | | | N | Capability | | | | | | Mandatory- 5 5.5.1 Unsigned32 | | | | | N | Capability | | | | | | Optional- 6 5.5.2 Unsigned32 | | | | | N | Capability | | | | | | User-Data 7 5.13 OctectString | | | | | N | SIP-Number-Auth 8 5.8 Unsigned32 | | | | | N | Items | | | | | | SIP- 9 5.7.2 UTF8String | | | | | N | Authentication-Scheme | | | | | | SIP- 10 5.7.3 OctetString | | | | | N | Authenticate | | | | | | SIP- 11 5.7.4 OctetString | | | | | N | Authorization | | | | | | SIP- 12 5.7.5 OctetString | | | | | N | Authentication-Context | | | | | | SIP-Auth-Data- 13 5.7 Grouped | | | | | N | Item | | | | | | SIP-Item- 14 5.7 Unsigned32 | | | | | N | Number | | | | | | Server- 15 5.6 Enumerated | | | | | N | Assignment-Type | | | | | | Deregistration- 16 5.9 Grouped | | | | | N | Reason | | | | | | Reason- 17 5.6 Enumerated | | | | | N | Code | | | | | | Reason- 18 5.6 UTF8String | | | | | N | Info | | | | | | Charging- 19 5.1 Grouped | M | P | | | N | Information | | | | | | Primary - 20 5.1 DiameterURI | M | P | | | N | Event-Charging-Function-Name | | | | | | Secondary - 21 5.1 DiameterURI | M | P | | | N | Event-Charging-Function-Name | | | | | | Primary - 22 5.1 DiameterURI | M | P | | | N | Charging-Collection-Function-Name | | | | | | Secondary - 23 5.1 DiameterURI | M | P | | | N | Charging-Collection-Function-Name | | | | | | Belinchon et all [Page 26] INTERNET-DRAFT Diameter Multimedia Application February, 2003 User- 24 5.12 Enumerated | | | | | N | Authorization-Type | | | | | | User- Data- 25 5.15 Enumerated | | | | | N | Request-Type | | | | | | User- Data- 26 5.14 Enumerated | | | | | N | Already-Available | | | | | | Confidentiality- 27 5.14 OctetString | | | | | N | Key | | | | | | Integrity- 28 5.14 OctetString | | | | | N | Key | | | | | | 5.1 Charging-Information AVP The Charging-Information (AVP code TBD) is of type Grouped, and contains the addresses of the charging functions. AVP format Charging-Information :: = < AVP Header : TBD > [ Primary-Event-Charging-Function-Name ] [ Secondary-Event-Charging-Function-Name ] [ Primary-Charging-Collection-Function-Name ] [ Secondary-Charging-Collection-Function-Name ] *[ AVP] 5.1.1 Primary-Event-Charging-Function-Name AVP The Primary-Event-Charging-Function-Name AVP (AVP Code TBD) is of type DiameterURI. This AVP contains the address of the Primary Event Charging Function. 5.1.2 Secondary -Event-Charging-Function-Name AVP The Secondary-Event-Charging-Function-Name AVP (AVP Code TBD) is of type DiameterURI. This AVP contains the address of the Secondary Event Charging Function. 5.1.3 Primary-Charging-Collection-Function-Name AVP The Primary-Charging-Collection-Function-Name AVP (AVP Code 22) is of type DiameterURI. This AVP contains the address of the Primary Charging Collection Function. 5.1.4 Secondary -Charging-Collection-Function-Name AVP The Secondary-Charging-Collection-Function-Name AVP (AVP Code 23) is of type DiameterURI. This AVP contains the address of the Secondary Charging Collection Function. 5.4 Server-Name AVP Belinchon et all [Page 27] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The Server-Name AVP (AVP Code TBD) is of type UTF8String. This AVP contains a SIP-URL (as defined in [5] and [6]) used to identify a SIP server. The HSP MAY include the Server-Name AVP to inform the Diameter server which SSP is assigned to the SIP user. 5.5 Server-Capability AVP The Server-Capability AVP (AVP Code TBD) is of type Grouped. This AVP is used to indicate support for particular SIP capability, and contains the information to assist the HSP in the selection of an SSP. Server-Capability ::= < AVP Header: TBD > *[ Mandatory-Capability ] *[ Optional-Capability ] *[ Server-Name ] *[ AVP ] 5.5.1 Mandatory-Capability AVP The Mandatory-Capability AVP (AVP Code TBD) is of type Unsigned32. The value included in this AVP can be used to represent a single determined mandatory capability of an SSP. Each mandatory capability available in an individual operatorĘs network shall be allocated a unique value. The allocation of these values to individual capabilities is an operator issue. 5.5.2 Optional-Capability AVP The Optional-Capability AVP (AVP Code TBD) is of type Unsigned32. The value included in this AVP can be used to represent a single determined optional capability of an SSP. Each optional capability available in an individual operatorĘs network shall be allocated a unique value. The allocation of these values to individual capabilities is an operator issue. 5.6 Server-Assignment-Type AVP The Server-Assignment-Type AVP (AVP code TBD) is of type Enumerated, and indicates the type of server update being performed in a Server- Assignment-Request operation. The following values are defined: NO_ASSIGNMENT (0) This value is used to request from AAA the user profile assigned to one or more public identities, without affecting the registration state of those identities. REGISTRATION (1) Belinchon et all [Page 28] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The request is generated as a consequence of a first registration of an identity. RE_REGISTRATION (2) The request corresponds to the re-registration of an identity. UNREGISTERED_USER (3) The request is generated because the SSP received an INVITE for a public identity that is not registered. TIMEOUT_DEREGISTRATION (4) The SIP registration timer of an identity has expired. USER_DEREGISTRATION (5) The SSP has received a user initiated de-registration request. TIMEOUT_DEREGISTRATION_STORE_SERVER_NAME (6) The SIP registration timer of an identity has expired. The SSP keeps the user data stored in the SSP and requests AAA to store the SSP name. USER_DEREGISTRATION_STORE_SERVER_NAME (7) The SSP has received a user initiated de-registration request. The SSP keeps the user data stored in the SSP and requests AAA to store the SSP name. ADMINISTRATIVE_DEREGISTRATION (8) The SSP, due to administrative reasons, has performed the de- registration of an identity. AUTHENTICATION_FAILURE (9) The authentication of a user has failed. AUTHENTICATION_TIMEOUT (10) The authentication timeout has expired. 5.7 SIP-Auth-Data-Item AVP The SIP-Auth-Data-Item (AVP code TDB) is of type Grouped, and contains the authentication and/or authorization information for the Diameter client. SIP-Auth-Data-Item :: = < AVP Header : TBD > [ SIP-Item-Number ] [ SIP-Authentication-Scheme ] [ SIP-Authenticate ] [ SIP-Authorization ] [ SIP-Authentication-Info ] [ SIP-Authentication-Context ] [Confidentiality-Key] Belinchon et all [Page 29] INTERNET-DRAFT Diameter Multimedia Application February, 2003 [Integrity-Key] * [ AVP ] 5.7.1 SIP-Item-Number AVP The SIP-Item-Number (AVP code TDB) is of type Unsigned32, and is included in a SIP-Auth-Data-Item grouped AVP in circumstances where there are multiple occurrences of SIP-Auth-Data-Item AVPs, and the order in which they should be processed is significant. In this scenario, SIP-Auth-Data-Item AVPs with a low SIP-Item-Number value (such as 1) should be processed before SIP-Auth-Data-Items AVPs with a high SIP-Item-Number value (such as 13). 5.7.2 SIP-Authentication-Scheme AVP The SIP-Authentication-Scheme AVP (AVP code TBD) is of type UTF8String and indicates the authentication scheme used in the authentication of SIP messages. Current values are "Basic" and "Digest", defined in [8]. 5.7.3 SIP-Authenticate AVP The SIP-Authenticate AVP (AVP code TBD) is of type UTF8String and contains the data portion of the WWW-Authenticate or Proxy- Authenticate SIP headers if present in a SIP response. 5.7.4 SIP-Authorization AVP The SIP-Authorization AVP (AVP code TBD) is of type UTF8String and contains the data portion of the Authorization or Proxy-Authorization SIP headers if present in a SIP request. 5.7.5 SIP-Authentication-Info AVP The SIP-Authentication-Info AVP (AVP Code TBD) is of type OctetString and contains additional authentication information sent by the AAA server in case of Digest authentication. It follows the format defined in RFC2617 for the Authentication-Info Header (sect 3.2.3). The content of this AVP is to be mapped to the SIP Authentication- Info header upon reception by the SIP server. 5.7.6 SIP-Authentication-Context AVP The SIP-Authentication-Context AVP (AVP code TBD) is of type OctectString, and contains authentication-related information relevant for performing the authentication but that is not part of the SIP authentication headers. Belinchon et all [Page 30] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Some mechanisms (e.g. PGP, digest with quality of protection set to auth-int [RFC 2617], digest with predictive nonces [7] or sip access digest [8]) request that part or the whole SIP request is passed to the entity performing the authentication. In such cases the SIP- Authentication-Context AVP would be carrying such information. 5.7.7 Confidentiality-Key AVP The Confidentiality-Key (AVP code 27) is of type OctetString, and contains the Confidentiality Key (CK). 5.7.8 Integrity-Key AVP The Integrity-Key (AVP code 28) is of type OctetString, and contains the Integrity Key (IK). 5.8 SIP-Number-Auth-Items AVP The SIP-Number-Auth-Items AVP (AVP Code TBD) is of type Unsigned32 and indicates the number of authentication and/or authorization vectors provided by the Diameter server. When used in a request, it indicates the number of SIP-Auth-Data- Items the SSP is requesting. This can be used, for instance, when the SSP is requesting several pre-calculated authentication vectors. In the answer message the SIP-Number-Auth-Items AVP indicates the actual number of items provided by the Diameter server. 5.9 Deregistration-Reason AVP The Deregistration-Reason AVP (AVP Code TBD) is of type Grouped, and indicates the reason for a deregistration operation. Message format Deregistration-Reason::= < AVP Header: TBD > { Reason-Code } [ Reason-Info ] * [ AVP ] 5.9.1 Reason-Code AVP The Reason-Code AVP (AVP code TBD) is of type Enumerated, and defines the reason for the network initiated de-registration. The following values are defined: PERMANENT_TERMINATION (0) NEW_SERVER_ASSIGNED (1) SERVER_CHANGE (2) REMOVE_SSP (3) 5.9.2 Reason-Info AVP Belinchon et all [Page 31] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The Reason-Info AVP (AVP code TBD) is of type UTF8String, and contains textual information to inform the user about the reason for a de-registration. 5.10 Public-Identity AVP The Public-Identity AVP (AVP Code TBD) is of type OctetString, encoded in the UTF-8 format. The syntax of this AVP corresponds either to a SIP URL (with the format defined in [5] and [6]) or a TEL URL (with the format defined in [7]). This AVP contains the SIP public identity of a user in the IMS. The Diameter client (HSP or SSP) uses information found in the header of the SIP messages (e.g. To: field in REGISTER messages or From: field in INVITE messages) to construct the Public-Identity AVP. 5.11 Visited-Network-Identifier AVP The Visited-Network-Identifier AVP (AVP Code TBD) is of type OctetString. This AVP contains an identifier that helps the home network to identify the visited network (e.g. the visited network domain name). 5.12 User-Authorization-Type AVP The User-Authorization-Type AVP (AVP code 24) is of type Enumerated, and indicates the type of user authorization being performed in a User Authorization operation, i.e. UAR command. The following values are defined: REGISTRATION (0) This value is used in case of the initial registration or re- registration. HSP determines this from the Expires field in the SIP REGISTER method if it is not equal to zero. This is the default value. DE_REGISTRATION (1) This value is used in case of the de-registration. HSP determines this from the Expires field in the SIP REGISTER method if it is equal to zero. REGISTRATION_AND_CAPABILITIES (2) This value is used in case of initial registration or re-registration and when the HSP explicitly requests SSP capability information from the AAA. 5.13 User-Data AVP Belinchon et all [Page 32] INTERNET-DRAFT Diameter Multimedia Application February, 2003 The User-Data AVP (AVP Code TBD) is of type OctetString, and MUST NOT be interpreted by the Diameter protocol. This AVP contains the user profile data required for a SIP server to give service to a user. 5.14 User-Data-Already-Available AVP The User-Data-Already-Available AVP (AVP code TBD) is of type Enumerated, and indicates to the AAA whether or not the SSP already has the part of the user profile that it needs to serve the user. The following values are defined: USER_DATA_NOT_AVAILABLE (0) The SSP does not have the data that it needs to serve the user. USER_DATA_ALREADY_AVAILABLE (1) The SSP already has the data that it needs to serve the user. 5.15 User-Data-Request-Type AVP The User-Data-Request-Type AVP (AVP code TBD) is of type Enumerated, and indicates the type of user profile the SSP is requesting from the AAA . The following values are defined: COMPLETE_PROFILE (0) This value is used to request from the AAA the complete user profile corresponding to one or more public identities. REGISTERED_PROFILE (1) This value is used to request from the AAA the registered part of the user profile corresponding to one or more public identities. UNREGISTERED_PROFILE (2) This value is used to request from the AAA the unregistered part of the user profile corresponding to one or more public identities. 6. Authentication Details Authenticating a mobile user can occur through various mechanisms (http basic or digest authentication have currently been prescribed), with the actual authentication being performed in either the SIP server or the AAA server. The choice of the server will determine the AVPs to be utilized in the SIP-Auth-Data-Item grouped AVP, as well as a few AVPs in the MAR/MAA. In the event that the SIP server performs the authentication of a mobile user, the MAR from the SIP server to the AAA server will include the User-Name and Public-Identity AVPs as necessary, as well a SIP-Number-Auth-Items AVP to indicate how many authentication vectors (the actual contents of the vector are dependent upon the Belinchon et all [Page 33] INTERNET-DRAFT Diameter Multimedia Application February, 2003 authentication method) are being requested. In the MAA, the AAA server SHOULD indicate how many SIP-Auth-Data-Item AVPs are present with the Number-Auth-Items AVP, and may be different from the amount requested in the MAR. If multiple SIP-Auth-Data-Item AVPs are present, and their ordering is significant, the Item-Number MUST be included in each grouping. The Authentication-Scheme and SIP- Authenticate AVPs will contain data (typically a challenge of some kind) to be used by the mobile user to authenticate itself. The SIP- Authorization AVP will contain the response which is expected from the user. In order to support some auth methods which combine key distribution with authentication, Confidentiality-Key and Integrity- Key AVPs are included. In the event that the AAA server performs the authentication of a mobile user, the MAR from the SIP server will include a single SIP- Auth-Data-Item AVP. The SIP-Authentication-Scheme and SIP Authorization AVPs will contain the relevant parameters from the SIP message if present, and if necessary, the SIP-Authentication-Context AVP will contain any additional information needed to perform the authentication. If the authentication is successful, the MAA will contain a Result-Code AVP indicating success, and if necessary, the SIP-Auth-Data-Item AVP may be included to carry session keys back to the SIP server. If the authentication is unsuccessful due to missing credentials, the MAA will include an SIP-Auth-Data-Item with the SIP- Authentication-Scheme and SIP-Authenticate AVPs containing data (typically a challenge of some kind) to be used by the mobile user to authenticate itself. 7. IANA Considerations The Application-Id for the multimedia application has to be assigned by IANA. Command Code values are assigned by IANA according to reference [8]. The Diameter multimedia application will make use of the values 300- 305. 8 Acknowledgements The authors would like to thank Tony Johansson and Kevin Pursuer for their invaluable contribution to the start up of this application and the continuous progress. 9 References 9.1 Normative References Belinchon et all [Page 34] INTERNET-DRAFT Diameter Multimedia Application February, 2003 [1] Loughney, Camarillo, "Authentication, Authorization and Accounting Requirements ", draft-ietf-sipping-aaa-req-02.txt, IETF work in progress, Feb 2003 [2] Calhoun, Akhtar, Arkko, Guttman, Rubens, Zorn, "Diameter Base Protocol", draft-ietf-aaa-diameter-17.txt, IETF work in progress, Dic 2002 [3] Calhoun, Johansson, Perkins, "Diameter Mobile IPv4 Application," draft-ietf-diameter-mobileip-13.txt, IETF work in progress, October 2002 [4] M. Handley, H. Schulzrinne, E. Schooler, J. Rosenberg, "SIP: Ses”sion Initiation Protocol". RFC 3261, June 2002 [5] IETF RFC 2396: "Uniform Resource Identifiers (URI): generic syntax" [6] IETF RFC 2806: "URLs for Telephone Calls" [7] IETF RFC 2617: "HTTP Authentication: Basic and Digest Access Authentication" 9.2 Non-Normative References [8] J. Loughney, "Provisional Diameter Command Codes for 3GPP", draft-loughney-aaa-cc-3gpp-01.txt, IETF work in progress, Dic 2002 [9] IETF RFC 2119: "Key words for use in RFCs to Indicate Requirement Levels" [10] M. Garcia-Martin, "3rd-Generation Partnership Project (3GPP) Release 5 requirements on the Session Initiation Protocol (SIP) ", draft-ietf-sipping-3gpp-r5-requirements-00.txt, IETF work in progress, Oct 2002 [11] Pat R. Calhoun, Glen Zorn, David Spence, David Mitton, "Diameter Network Access Server Application", draft-ietf-aaa-diameter-nasreq- 11.txt, IETF work in progress, Feb 2003 [12] J. Loughney, G. Camarillo, "Authentication, Authorization and Accounting Requirements for the Session Initiation Protocol", draft- ietf-sipping-aaa-req-02.txt, IETF work in progress, Feb 2003 10 Authors' Addresses Maria-Carmen Belinchon Phone: +34 913393535 Ericsson Spain Fax: +34 913392538 Via de los Poblados, 13 28033 Madrid Belinchon et all [Page 35] INTERNET-DRAFT Diameter Multimedia Application February, 2003 Spain E-mail: maria.c.belinchon@ericsson.com Miguel-Angel Pallares Phone: +34 913394222 Ericsson Spain Fax: +34 913392538 Via de los Poblados, 13 28033 Madrid Spain E-mail: miguel.pallares@ericsson.com Carolina Canales Phone: +34 913392680 Ericsson Spain Fax: +34 913392538 Via de los Poblados, 13 28033 Madrid Spain E-mail: carolina.canales-valenzuela@ece.ericsson.se Miguel Garcia Phone: +358 9 2993553 Ericsson Finland Fax: +358 9 2993052 Hirsalantie 11 02420 Jorvas Finland E-mail: Miguel.A.Garcia@ericsson.com Peter J. McCann Phone: +1 630 713 9359 Lucent Technologies Fax: +1 630 713 4982 Rm 2Z-305 263 Shuman Blvd Naperville, IL 60566-7050 USA E-Mail: mccap@lucent.com Jaakko Rajaniemi Phone: +358 50 3391387 Nokia Networks Fax: +358 9 51130163 P.O. Box 301 00045 Nokia Group Finland E-mail: jaakko.rajaniemi@nokia.com Kalle Tammi Phone: +358 Nokia Networks Fax: +358 P.O. Box 301 00045 Nokia Group Finland E-mail: kalle.tammi@nokia.com 11. Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. Belinchon et all [Page 36] INTERNET-DRAFT Diameter Multimedia Application February, 2003 This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this docu” ment itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of develop” ing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The lim” ited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DIS” CLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Belinchon et all [Page 37]