e. The information transmitted concerns the list of AMF entities in the region concerned, the list of cells served by the node and security information; - updating the configuration of the nodes such as updating the TAI lists; - deactivation of cells in the event of inactivity of a neighboring cell to reduce the carbon impact; - cell activation; - error notification when an error is detected on a received message, a message for which there is no failure response; - re-initialization of an NG-RAN node. 2.2.3. NG-AP procedures The 5G core network provides data transmission services by establishing tunnels between the mobile and a data network (DN). PDU sessions are initiated by the mobile and are controlled by the AMF function. To set up a PDU session, the mobile first establishes a signaling radio bearer (SRB) with gNB to transmit NAS messages towards the core network. The user plane is on the control of the core network from gNB to the data network (DN). NG-RAN Network - Protocol Architecture Connection management includes the establishment and release of signaling between the mobile and the AMF entity through the N1 interface (Figure 2.10). The N1 interface is based on the Uu interface (between the mobile and the radio access) and on the N2 interface between the radio node and the AMF function. The SM-NAS message (Session Management NAS) controls the establishment of the session. This message is transmitted between the mobile and the SMF function. The content of the SM-NAS message is transparent to the AMF function. The control plane allows the establishment of a user plane between the mobile and the 5G core network. The established tunnel can be an IP connection (IPv4, Ipv6) or a point-to-point Ethernet connection. The GTP-U encapsulation protocol allows multiple PDU sessions to be multiplexed between the radio node and the UPF, via the N3 interface. NG-AP protocols consist of elementary procedures (EP) which can be of two types: - class 1: request with response (failure or success, see Table 2.5); - class 2: r