This Annex describes Use Cases related to the exposure of events relating to 5G Media Streaming by the Data Collection AF instantiated in the 5GMS AF.

The Use Case for exposing QoE metrics for downlink media streaming as an event is in clause 6.4 of TS 23.288.

The 5GMSd Client collates feedback reports on currently consumed downlink media streaming content according to a provisioned Consumption Reporting Configuration it obtains from the Service Access Information for its Provisioning Session. The consumption reports include the media player entry point URL, the start time, duration and UE locations. The Media Session Handler sends the consumption reports to 5GMSd AF for subsequent event exposure to subscibed Event consumers. The 5GMSd Application Provider subscribes to downlink media streaming consumption events from the Data Collection AF, specifying an appropriate application filter in its subscription request. To drill down into downlink media streaming consumption at a finer geographical granularity, a location filter is also specified as part of the subscription. To analyse use of a new application feature in isolation as part of a beta testing programme, a user group filter corresponding to the test population is also specified. With the exposed event, the 5GMSd Applcation Provider performs data analytics to determine, for example, which media content is most popular in the 5GMS System, which media content is most popular at a specific location, or which portions of the media content are consumed. This helps the 5GMSd Application Provider to optimise distribution of the most popular media content in the 5GMS System. Alternatively, the NWDAF subscribes to this event for data analytics, exposing the results to the 5GMSd Application Provider.

The Media Session Handler invokes the Dynamic Policy API on the 5GMS AF via M5 to request a specific policy and charging treatment to be applied to a particular media streaming application data flow. As a result, the 5GMS AF invokes appropriate service operations on Network Functions in the 5G Core, e.g. Npcf_PolicyAuthorization or Nnef_AFSessionWithQoS, to effect the requested network QoS policy change. The 5GMS AF obtains status information (policy accepted, rejected, etc.) about these service operation invocations, and policy enforcement information, such as the enforcement method selected and the enforcement bit rate. After recording the invocation of the dynamic policies, the 5GMS AF reports these records to its subordinate Data Collection AF for exposure to subscribed Event consumers. The event for invocation of dynamic polices may include the timestamp when the Media Session Handler invokes the dynamic function in 5GMS AF, the requested policy template identifier, the status information, etc. The Event Consumer AF within the 5GMS Application Provider or the NWDAF subscribes to events of this type from the Data Collection AF, specifying the relevant application filter and any relevant location and/or user filters in its subscription request. Using the details about the invocations for dynamic policies, the 5GMS Application Provider or the NWDAF analyse the network quality provided by the 5G System and the dynamic network requirements for this media streaming service. Alternatively, the NWDAF subscribes to the event, specifying any relevant filters, and exposes analytics results to the 5GMS Application Provider, enabling the 5GMS Application Provider to optimise the media streaming service, e.g. by provisioning more appropriate policy templates or by negotiating more suitable Service Level Agreement (SLA) with the MNO.

The AF-based Network Assistance feature enables a UE to receive a bit rate recommendation from a 5GMS AF providing the Network Assistance server function. The 5GMS AF uses the Npcf_PolicyAuthorization notification or Nnef_MonitoringEvent procedure to receive notifications of network QoS changes, e.g. estimation of throughput, recommendation of a bit rate. The 5GMS AF receives these policy change notifications asynchronously. The 5GMS AF reports the invocation of AF-based network assistance to its subordinate Data Collection AF, including information about requested QoS and recommended QoS. The Data Collection AF subsequently exposes this UE data to the Event Consumer AF within the 5GMS Application Provider. Using this information, the 5GMS Application Provider is able to optimise the use of the 5GMS System, e.g. by performing dynamic congestion window adjustment. Data collection and reporting may also be used in case the UE implements ANBR-based Network Assistance. In this case the Direct Data Reporting Client reports the invocations of ANBR-based Network Assistance directly to the 5GMS AF's subordinate Data Collection AF. The NWDAF subscribes to events of this type at the Data Collection AF, specifying the relevant application filter and any relevant location and/or user filters. Based on the requested QoS and recommended QoS in the exposed events, the NWDAF analyses whether the current network deployment or status can support the currently provisioned media streaming services, and exposes these results to the OAM for better network optimization.