Section: 4.25.9 NEF Anchored Group NIDD via NEF anchored unicast MT data
Content: Figure 4.25.9-1 illustrates the procedure by which the AF can send a Group NIDD addressed to External Group Identifier. It is a pre-requisite assumption that the NEF has already resolved the mapping of External Group Identifier to individual SUPIs with the help of UDM during NIDD Configuration procedure as specified in clause 4.25.3. Standalone MT NIDD procedure specified in clause 4.25.5 is re-used by NEF to unicast the MT data to each UE. Figure 4.25.9-1: NEF Anchored Group NIDD via NEF anchored unicast data 1. If AF has already used the NIDD Configuration procedure of clause 4.25.3 to activate the NIDD service for a group of UEs and has unstructured data to send to the group identified by an External Group Identifier, the AF sends a Nnef_NIDD_Delivery Request (External Group Identifier, TLTRI, unstructured data, Reliable Data Service Configuration) message to the NEF. Reliable Data Service Configuration is an optional parameter that is used to configure the Reliable Data Service. When unstructured data is sent to an External Group Identifier, the AF shall not request acknowledgement in the Reliable Data Service Configuration. 2. Based on the existing NIDD configuration of the UE Group (see clause 4.25.3), the NEF sends a single Nnef_NIDD_Delivery Response to AF to acknowledge the acceptance of the Group NIDD delivery request in step 1. 3. The NEF uses the NEF anchored Mobile Terminated Data Transport procedure that is specified in steps 2-16 in clause 4.25.5 to send the same MT NIDD to each UE in the group. 4. After executing step 3 for all UEs in the group, the NEF sends aggregated response in Nnef_NIDD_GroupDeliveryNotify message. If some target UEs were not reachable due to UE power saving, then the NEF does not buffer the MT NIDD, but it may include indication on the expected reachability of those UEs in its response to AF in this step. If the delivery towards certain UE failed, the NEF may include the cause value.