1. Communication Service Identifier Requirements on SIP draft-loreto-3gpp-ics-requirements.txt Salvatore.Loreto@ericsson.com

2. Overview AS Identification of Communication Services is useful to –Route the service signaling to the correct Application Server –Identify a proper terminal (UA) –Address a proper application inside the terminal

3. So far, it has been assumed that the types of the media streams of a session can uniquely identify how the user can communicate. It has also been assumed that for each media only one media handling is possible. Present Behavior

4. Multi-service Architecture In a multi-service architecture, a particular medium can be used by a number of different services, each one using a different media handling. –One such example is audio (RTP media) that is used in both push-to-talk and standard audio call, but with different service behavior. For this reason –a particular medium does not unambiguously identify a service. –the full set of the media involved in a particular service does not unambiguously identify a service.

5. Multi-service Architecture (cont.) There is a need to be able to group –a set of media types –a particular service logic There is a need to identify groupings. The identifiers of such groups should be visible to the SIP entities (i.e., proxies and UAs) handling a request.

6. Communication Service A SIP Communication Service is an aggregation of one or several media components and a particular service logic.

7. Communication Service: Requirements (1 of 3) The Communication Service Identifier (CSID) identifies the communication services and shall be included in the relevant SIP methods. It shall be possible for all entities in the networks (originating and terminating side), which evaluate the different possible protocol elements in order to determine which communications service is requested, arrive at the same result.

8. Communication Service: Requirements (2 of 3) It shall be possible for the UA to –identify a communication service uniquely by the Communication Service Identifier. –use the Communication Service Identifier as a key for dispatching the SIP Message to the appropriate communication service logic. –indicate its service capabilities to the network, e.g. during registration, using the Communication Service Identifier.

9. Communication Service: Requirements (3 of 3) The usage of Communication Service Identifier shall not adversely affect interoperability or restrict the inherent capabilities of SIP The CSID should be informative. –If the UA doesnt understand the CSID, it continues to process the request using the standard media handling and service logic.

10. Communication Service Communication Service 1 Communication Service 2 Communication Service 3

11. Communication Service: IMS Requirements Based on operator policy the S-CSCF or an AS shall be able to validate a Communication Service Identifier in a SIP request. It shall be possible for the S-CSCF to invoke appropriate service logic based on the communication service identifier, as for all other information elements contained in a SIP request – e.g. route a SIP request containing a communication identifier to the correct AS.

12. Application: Requirements The logic of each of the standardized communication service can be utilized by a number of applications, each of them implementing a particular end-user service. In the terminal there is a need to dispatch a SIP message to the correct application. A SIP message can be dispatched to the correct communication service and a correct application can be invoked and receive this message.

13. UA structure GUI Application 2 Communication Service 2 Communication Service 1 Communication Service 3 Application 1 Application 3 Application n

14. Application: Requirements (cont.) It shall be possible for the UA a – to set the Application Reference in a SIP request e.g. in the REGISTER and INVITE request. –to identify an end-user application uniquely by the Application Reference contained in a received SIP request. –to invoke appropriate application that is using a communication service based on the Application Reference.