lity in the network Authentication Server Authenticates the UE and provides related keying material for it Function (AUSF) Security Edge Protection Provides Message filtering and policing on inter-PLM control plane Proxy (SEPP) interfaces and hides network topology from other vendors as it can act as a single point of contact Network Data Analytics Provides slice specific network data analytics to PCF and NSSF Function (NWDAF) Location Management Obtains location measurements equally from UE and Radio Access Function (LMF) Network 5.4 5G RAN Architecture The 5G radio access architecture consists of two basic elements as follows: Central Unit (CU), which is intended to handle relatively higher layers above the phys- ical layer. The physical realization of CU could be either dedicated hardware or a radio-cloud type of implementation. The CU is connected on one hand to the Dis- tributed Unit (DU) and on the other hand to the 5G core network (Next Generation Core (NGC), as shown in Figure 5.5. The DU, which is located on the cell site together with the antennas and the RF unit. The DU is expected to handle especially time-critical processing which does not tol- erate too much delay to enable processing away from the cell site. In the considerations in 3GPP, the approach with RF only on the site (with antennas) has not been considered desirable due to the very high transmission requirements of sending IQ samples. Although such an approach was used in some markets with LTE, the larger number of antennas as well as the larger bandwidths considered make the required data rates SO massive that they are not often seen in large-scale network deployments. The following interfaces are defined as part of the 5G radio access architecture: The F1 interface connects the CU to one or more DUs. A single CU is expected to be able to handle multiple DUs. The Xn-interface connects the different CUs together. When considering the early deployment architecture with the LTE core (EPC), the interface between LTE eNB and 5G gNB is called t