5G (NR) System Network Functions and Entities

As 5G (NR) supports increasingly more connections and functions, the number of network functions and entities in the system is also constantly increasing. 3GPP defines network functions and entities in Release 18.5 as follows:

I. Network Function (NF) Units The 5G system includes the following functional units:

•  AUSF (Authentication Server Function);
• AMF (Access and Mobility Management Function);
• DN (Data Network), specifically including: operator services, internet access, or third-party services;
• UDSF (Unstructured Data Storage Function);
• NEF (Network Exposure Function);
• NRF (Network Repository Function);
• NSACF (Network Slice Admission Control Function);
• NSSAAF (Network Slice-Specific and SNPN Authentication and Authorization Function);
• NSSF (Network Slice Selection Function);
• PCF (Policy Control Function);
• SMF (Session Management Function);
• UDM (Unified Data Management);
• UDR (Unified Data Repository). - UPF (User Plane Functions).
• UCMF (UE Radio Capability Management Functions).
• AF (Application Functions).
• UE (User Equipment).
• RAN (Radio Access Network).
• 5G-EIR (5G Device Identity Registration).
• NWDAF (Network Data Analysis Functions).
• CHF (Charging Functions).
• TSN AF (Time-Sensitive Network Adapter).
• TSCTSF (Time-Sensitive Communications and Time Synchronization Functions).
• DCCF (Data Collection Coordination Functions).
• ADRF (Analysis Data Repository Functions).
• MFAF (Message Frame Adapter Functions).
• NSWOF (Non-Seamless WLAN Offload Functions).
• EASDF (Edge Application Server Discovery Functions).

*Functions provided by DCCF or ADRF can also be carried by NWDAF.

II. Network Entities The 5G system, supporting connectivity with non-3GPP Wi-Fi, WLAN, and wired access networks, also includes the following entity units in its architecture:

• SCP (Service Communication Agent).
• SEPP (Secure Edge Protection Agent).
• N3IWF (Non-3GPP Interoperability Function).
• TNGF (Trusted Non-3GPP Gateway Function).
• W-AGF (Wired Access Gateway Function).
• TWIF (Trusted WLAN Interoperability Function).