Section: 4.15.6.13 Multi-member AF session with required QoS 4.15.6.13.1 General Descriptions
Content: This clause describes the procedure to request QoS and to perform QoS monitoring for the traffic flows for the communication between an AF and a set of UEs, identified by the list of UE address(es). For every UE in the set, this list contains the IP address and the port number that are used by the UE for the communication with the AF. The NEF receives the request for a Multi-member AF session with required QoS for a set of UEs identified by their addresses. The NEF then maps the request for Multi-member AF session with required QoS to individual requests for AF session with required QoS (i.e., one request for individual AF session with required QoS per UE address) and interacts with each of the UE's serving PCFs on a per AF session basis. The interaction follows the AF session with required QoS procedure as described in clauses 4.15.6.6 and 4.15.6.6a, except that the involvement of the TSCTSF and the provisioning of TSCTSF related information are not supported. The NEF receives the outcome of the individual requests for AF session with required QoS corresponding to each UE's IP address and consolidates them into a single response before forwarding it to the AF based on a locally configured timer (which could be set to zero). NOTE 1: The consolidation of the outcome of the individual requests and the locally configured timer allow the optimization of the NEF to AF signalling according to the specific Multi-member AF session with required QoS. Multiple responses could be sent by an NEF (as RAN nodes may responds late or signalling messages may get lost) and the details of the NEF behaviour (e.g. handling of UE addresses for which no response has been received within the locally configured timer) are to be defined by stage 3. The AF can subscribe to QoS Monitoring (as described in clause 5.45 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]) for the Multi-member AF session with required QoS. If so, QoS monitoring will be activated by the NEF for the whole set of UEs by interacting with each of the UE's serving PCFs on a per AF session basis. If the AF request contains QoS monitoring information without an indication of direct event notification, the NEF shall include that indication in the request to ensure that QoS Monitoring reports shall be sent by the UPF directly to the NEF. The NEF forwards the QoS Monitoring reports to the AF together with the respective UE address individually or, optionally, in an aggregated manner based on a locally configured timer. When the AF subscribes to QoS Monitoring of UL and/or DL data rate (as described in clause 5.45 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]) for the set of UEs, the AF may provide a Consolidated Data Rate threshold that is to be stored in the NEF. The Consolidated Data Rate threshold defines the upper bound of the aggregated data rate across all traffic flows corresponding to the list of UE addresses of the Multi-member AF session with required QoS. The AF may provide in addition a specific list of UE addresses subject to Consolidated Data Rate monitoring (which has to be the subset of the list of UE addresses for the Multi-member AF session), if only a part of the UEs participate in the current communication with the AF and the NEF maintains this list as well. The NEF aggregates the QoS Monitoring reports for data rate for those UEs identified by the specific list of UE addresses subject to Consolidated Data Rate monitoring (if available) or otherwise by the list of UE addresses for the Multi-member AF session with required QoS. The QoS Monitoring reports for data rate will then be sent to the AF by NEF, only if the aggregated data rate exceeds the Consolidated Data Rate threshold. The following Table 4.15.6.13.1-1 describes the 4 types of requests for the Multi-member AF session with required QoS by the NEF and the corresponding requests to/from PCF using Npcf_PolicyAuthorization service. There may be different PCFs serving the PDU Sessions associated with the UE addresses in the Nnef_AFSessionWithQoS Request. Table 4.15.6.13.1-1: Mapping of requests for Multi-member AF session with required QoS service to the corresponding Npcf_PolicyAuthorization service operations NOTE 2: It is expected that the AF requests QoS and QoS monitoring for a specific traffic flow (used for the communication between a UE address and the AF) with either the procedure for Multi-member AF session with required QoS (described in this clause) or the procedure for AF session with required QoS as described in clause 4.15.6.6 and 4.15.6.6a.