Section: 4.15.6.13.3 Procedure for updating a Multi-member AF session with required QoS
Content: Figure 4.15.6.13.3-1: Procedure for updating a Multi-member AF session with required QoS 1. The AF which controls the Multi-member AF Session with required QoS invokes the Nnef_AFSessionWithQoS_Update Request to update the list of UE addresses and/or to update the QoS and/or to update the QoS monitoring and/or to update the Consolidated Data Rate monitoring. The Nnef_AFSessionWithQoS_Update request includes the Transaction Reference ID and one or more of the parameters that are listed in step 1 of the procedure for creating a Multi-member AF session with required QoS in clause 4.15.6.13.2 which the AF needs to update (or provide for the first time). NOTE 1: For example, the AF can subscribe to QoS monitoring or Consolidated Data Rate monitoring for the Multi-member AF session with required QoS if this has not been done during the procedure for creating a Multi-member AF session with required QoS, as described in clause 4.15.6.13.2. NOTE 2: If AF needs to terminate the Consolidated Data Rate monitoring for the Multi-member AF session with required QoS, the AF does not include the Consolidate Data Rate threshold in the AF request. 2. The NEF authorizes the AF request and may apply policies to control the overall amount of QoS authorized for the AF. If the authorisation is not granted, all following steps are skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed. The NEF performs Consolidated Data Rate monitoring only when both the Consolidated Data Rate threshold and a request to do QoS Monitoring of data rate are provided by the AF. 3-5. When the AF provides an Nnef_AFSessionWithQoS_Update Request in order to add/update/remove the Consolidated Data Rate threshold or the list of UE addresses subject to Consolidated Data Rate monitoring, the NEF updates its local context and does not interact with the PCF(s) (unless required for reasons described in the following). When the AF provides an Nnef_AFSessionWithQoS_Update Request in order to update the list of UE addresses, to update the QoS and/or to update the QoS monitoring, the NEF refers to the locally stored information (i.e. the list of UE addresses, the QoS and the QoS monitoring information) and determines which new UE address is to be added to the list, which of the existing UE address is to be removed from the list and/or for which of the existing UE address(es) the QoS or the QoS monitoring (or both) is to be updated. Then, the NEF continues by invoking one of the following Npcf_PolicyAuthorization procedures for every affected UE address: a) If the NEF determines that a new UE is to be added to the list, the NEF performs steps 2a to 7 of clause 4.15.6.13.2 for the corresponding UE. The NEF uses the latest information on QoS and QoS monitoring for the interaction with the PCF. The NEF adds the address of the new UE to the locally stored list of UE addresses if the authorization was successful. b) If the NEF determines that an existing UE is to be removed from the list, the NEF initiates the Npcf_PolicyAuthorization_Delete as described in clause 5.2.5.3.4 excluding TSCTSF related info towards the PCF for the corresponding UE. The NEF removes the UE address from the locally stored list of UE addresses. c) If the NEF determines that an update of the QoS or the QoS monitoring or both for existing UE addresses is necessary, the NEF initiates the Npcf_PolicyAuthorization_Update to the respective UE's serving PCF(s) on a per AF session basis and step 4 in Figure 4.15.6.6a-1 applies. The NEF removes any UE addresses for which the authorization of the update request has failed from the list of UE addresses. The NEF stores any change to the QoS or the QoS monitoring information. 6. When an interaction with PCF(s) has occurred during step 5, the NEF aggregates the authorization responses from the PCF(s) and sends the Nnef_AFSessionWithQoS Update response (Transaction Reference ID, Result for list of UE addresses) with the aggregated authorization results to the AF. Result for list of UE addresses includes whether the request is granted or not for every UE address in the list. When no interaction with PCF(s) has occurred during step 4 and 5, the NEF sends the Nnef_AFSessionWithQoS Update response (Transaction Reference ID, Result) with the result of the Consolidated Data Rate monitoring related change to the AF. 7. For every UE address that has been added to the locally stored list of UE addresses, the NEF shall send a Npcf_PolicyAuthorization_Subscribe message to the respective PCF(s) to subscribe to notifications of Resource allocation status and may subscribe to other events described in clause 6.1.3.18 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20]. If an update of event subscription is requested by the AF, the NEF updates the event subscription with the respective PCF(s) for every UE address in the locally stored list of UE addresses. 8. Step 7 in Figure 4.15.6.6-1 applies, at least for those UE addresses for which the establishment or update of transmission resources was requested by the PCF(s). 9. When the establishment or update of transmission resources occurs, the NEF receives Npcf_PolicyAuthorization_Notify messages from the UE's serving PCF(s) about the Resource allocation status. The NEF aggregates the notifications from the respective UEs' serving PCFs before notifying the AF with a Nnef_AFSessionWithQoS_Notify message (Transaction Reference ID, Result for list of UE addresses). Result for list of UE addresses includes, for every UE address in the list, the information whether resources are allocated, resources are not allocated or resources are allocated while the currently fulfilled QoS matches an Alternative Service Requirement. The NEF updates the locally stored list of UE addresses by removing any UEs for which resources could not be allocated. NOTE 3: For those UE address(es) that did not get any resources, the AF may request resource reservation again, by adding them to the list of UE address(es) as described in clause 4.15.6.13.3. 10. As direct event notification is requested, the UPF(s) provide the QoS Monitoring events to the NEF using Nupf_EventExposure service as described in clause 5.2.26.2. 11. When the NEF receives QoS Monitoring events, the NEF sends Nnef_AFsessionWithQoS_Notify message with the individual or aggregated QoS Monitoring events to the AF as described for the QoS Monitoring and the Consolidated Data Rate monitoring in clause 4.15.6.13.1.