Section: A.1 PDU Session Establishment
Content: The following figure shows an example message flow for a PDU session establishment. 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.1-1: PDU session establishment 1. UE requests a PDU session establishment to AMF. 2. AMF sends a PDU SESSION RESOURCE SETUP REQUEST message to gNB, which includes the NAS message to be sent to the UE with NAS QoS related information. 3. gNB sends an RRCReconfiguration message to UE including the configuration of at least one DRB and the NAS message received at Step 2. 4. UE establishes the DRB(s) for the new PDU session and creates the QFI to DRB mapping rules. 5. UE sends an RRCReconfiguration Complete message to gNB. 6. gNB sends a PDU SESSION RESOURCE SETUP RESPONSE message to AMF. 7. User Plane Data can then be exchanged between UE and gNB over DRB(s) according to the mapping rules and between UPF and gNB over the tunnel for the PDU session. QFI marking over Uu is optional (see clause 12) while QFI marking over NG-U is always present.