• NGAP: NG Application Protocol used over N2 interface

  • S1AP: S1 Application Protocol used over S1-AP interface

  • Diameter: S6a, Gx interface

  • NAS: Non-Access-Stratum used between UE & MME/AMF.

  • PFCP: Packet Forwarding Control Protocol

  • GTPU: GTP user plane protocol. Used on s1-U, s5-U, N3, N9 interfaces

  • GTPv2: GTP control plane protocol used on s11 interface between MME & SGW

Network Functions

  • AMF: Access and Mobility Management Function

  • UPF: User Plane Function

  • SMF: Session Management Function

  • NRF: Network Repository Function

  • NSSF: Network Slice Selection Function

  • PCF: Policy & Charging Function

  • AUSF: Authentication Server Function

  • UDM: Unified Data Management

  • UDR: Unified Data Repository

  • CHF: Charging Function

  • NWDAF: Network Data Analytics Function

  • NEF: Network Exposure Function

  • MME: Mobility Management Entity

  • SGW: Serving Gateway

  • PGW: PDN Gateway

  • HSS: Home Subscriber Server

  • PCRF: Policy and Charging Rule Function

3gpp Interfaces

  • N2: gNodeB to AMF interface

  • N4: SMF to UPF interface

  • SBI interface

  • S1AP: eNodeB to MME interface


SA: Standalone Architecture URLLC : Ultra Reliable Low Latency Communication