Section: A.5 Release of QoS Flow with Explicit Signalling
Content: The following figure shows an example message flow when the gNB receives a request to release a QoS flow from CN that involves explicit NAS signalling. NAS procedures details between gNB and 5GC can be found in TS 23.501[ System architecture for the 5G System (5GS) ]  [3], TS 23.502[ Procedures for the 5G System (5GS) ]  [22] and TS 38.413[ NG-RAN; NG Application Protocol (NGAP) ]  [26]. Figure A.5-1: Release of QoS Flow with Explicit Signalling 0. PDU session and DRB(s) have been already established. 1. gNB receives a PDU SESSION RESOURCE MODIFY REQUEST message from AMF to release a QoS flow. 2. The gNB decides to release corresponding the QFI to DRB mapping rule. Since the DRB also carries other QoS flows, the DRB is not released. 3. gNB sends an RRCReconfiguration message to UE to release the QFI to DRB mapping rule. 4. UE updates the AS QFI to DRB mapping rules to release this QFI to DRB mapping rule. 5. UE sends an RRCReconfigurationComplete message to gNB. 6. gNB sends a PDU SESSION RESOURCE MODIFY RESPONSE message to AMF.