between the radio node and the AMF (Access and Mobility Management Function). It supports signaling via NG-AP (Next Generation Application Protocol); - the NG-U interface is the interface between the radio node and the UPF (User Plane Function) for tunneling traffic (the IP packet) via GTP-U (GPRS Tunneling Protocol). NG-RAN and 5G-NR The UPF is configured by the SMF (Session Management Function) under the control of the AMF. NG RAN Figure 1.6. NG-RAN general architecture The mobile exchanges data with the DN (Data Network) through logical connections called PDU (Protocol Data Unit) sessions. This logical connection is divided into two parts: - the NG-RAN ensures the connection of the mobiles with the base station and interconnects the control plane and user plane (traffic) of the mobile UE with the core network; - the 5G core network interconnects the NG-RAN, provides the interface to the DN, ensures the registration of mobiles, the monitoring of their mobility and the establishment of data sessions with the quality of the corresponding QoS (Quality of Service). 1.2.1. The NG-RAN The NG-RAN provides both an LTE radio interface and a 5G-NR radio interface. An NG-RAN node is: - a 5G base station (gNB), which provides the control plane services and the transmission of user plane data through the 5G-NR radio interface; - an advanced 4G base station (ng-eNB), providing control plane services and data transmission from the user plane to mobiles via the LTE radio interface. The NG-RAN node is responsible for managing radio resources, controlling the radio bearer establishment of the user plane and managing mobility during the session (handover). The mobile connects to one of the radio nodes. NG-RAN Network - Functional Architecture The NG-RAN node transfers the traffic data from the mobile to the UPF and data from the UPF to the mobile. When the NG-RAN node receives data from the mobile or from the UPF, it refers to the QFI (QoS Flow Identifier) for the implementation of the data scheduling mechanism. For outgoing data