 the corresponding low-level configuration (which the gNB-DU is in charge of). The Initial UL RRC Message Transfer message also includes the Cell Radio Network Temporary Identifier (C-RNTI) allocated by the gNB-DU. If the gNB-CU-CP accepts the request, it allocates a gNB-CU UE F1AP ID for the UE and generates the RRC Connection Setup message toward the UE. The RRC message is encapsulated in the F1AP DL RRC Message Transfer message and sent to the gNB-DU. 4. The gNB-DU sends the RRC Connection Setup message (received from the gNB-CU) to the UE. 5. The UE sends the RRC Connection Setup Complete message to the gNB-DU. 6. Similar to step 2, the gNB-DU encapsulates the RRC message in the F1AP UL RRC Message Transfer message and sends it to the gNB-CU-CP. 7. The gNB-CU-CP sends the Initial UE Message to the AMF, thus triggering the connec- tion establishment with the core network. 8. If the AMF accepts the request, it sends the Initial UE Context Setup Request message to the gNB-CU-CP. 9. The gNB-CU-CP sends the E1AP Bearer Context Setup Request message to establish the bearer context in the gNB-CU-UP. In the case of NG-RAN, the message carries the list of 4.4 Control-User Plane Separation PDU sessions to set up, which in turns contains a list of DRBs to set up up for each PDU session. The PDU sessions and DRB IEs contain all the information required by the gNB-CU-UP, such as QoS parameters, inactivity timers, slicing information, transport layer information, etc. 10. If the procedure is successful, the gNB-CU-UP sends the E1AP Bearer Context Setup Response message to the gNB-CU-CP. In the case of NG-RAN, the message contains the list of successfully established PDU sessions and the list of PDU sessions that could not be established. For each successfully established PDU session a list of successfully established DRBs and QoS flows is included. Furthermore, the response message also carries F1-U UL TEID and a transport layer address allocated by the gNB-CU-UP. 11. The gNB-CU-CP sends the UE Context Setup Request messag