Content for  TS 26.501  Word version:  17.2.0

This clause describes the provisioning for dynamic policy invocation and the establishment of a unicast downlink streaming session using the dynamic policy API. The establishment of the unicast downlink media streaming session uses 5GMSd AF interactions, as described in steps 4 to 8 of clause 5.1. The dynamic policy API allows separate handling of Service Data Flows within the same PDU Session. The Media Session Handler provides a Policy Template Id together with Service Data Flow Descriptions when requesting a dynamic policy. An example Policy Template Id value is "background_data". The Media Session Handler provides needed information to the 5GMSd AF, so that the 5GMSd AF can combine the semi-static parameters from a Policy Template (which is associated with the Policy Template Id) with the API parameters to trigger a dynamic PCC rule update using the NEF or PCF. The 5GMSd AF may trigger, for example, the "AF session with required QoS procedure" (see TS 23.502, clause 4.15.6.6) for updating QoS related dynamic PCC rules. For changing charging related rules, the 5GMSd AF may trigger the "Change the chargeable party during the session" procedure (see TS 23.502, clause 4.15.6.5).

The provisioning for the dynamic policy procedure follows generally the procedure from clause 5.3. Specifically, the Dynamic Policy feature is activated and, as result, the 5GMSd Application Provider is able to provision one or more Policy Templates. The domain model of M1d and M5d APIs is depicted in Figure 5.7.2-1. Realization of the dependencies between M1d and M5d data entries are up to implementation.

A Policy Template is identified by a Policy Template Id and contains semi-static parameters, including the API entry for the PCF/NEF interactions. The list of provisioned Policy Template Ids is communicated as valid Policy Template Ids to the Media Session Handler. The Media Session Handler uses one of the valid Policy Template Ids when invoking a dynamic policy.