5G Core reference

Network functions

The software functions that provide access control, session management, forwarding, policy, identity, discovery, analytics, exposure and charging in the 5G System.

AMF

Access and Mobility Management Function

Handles registration, connection, reachability, mobility and access-related control signalling.

SMF

Session Management Function

Creates and controls PDU sessions, selects user-plane functions and manages session policy.

UPF

User Plane Function

Forwards user packets between the radio access network and external data networks.

NSSF

Network Slice Selection Function

Supports selection of suitable network slice instances and serving AMF sets.

PCF

Policy Control Function

Provides policy rules affecting session, QoS, access and charging behaviour.

UDM

Unified Data Management

Manages subscriber-related data, identifiers and access to subscription information.

AUSF

Authentication Server Function

Supports authentication of devices accessing the 5G System.

NRF

Network Repository Function

Allows network functions to register their services and discover authorised service providers.

NEF

Network Exposure Function

Securely exposes selected network capabilities and events to authorised external applications.

AF

Application Function

Represents application influence on traffic routing, policy and service behaviour.

NWDAF

Network Data Analytics Function

Produces analytics about network load, behaviour, performance and events.

UDR

Unified Data Repository

Stores structured data used by authorised 5G Core functions.

UDSF

Unstructured Data Storage Function

Stores unstructured state information for stateless network-function implementations.

CHF

Charging Function

Collects charging information and supports converged charging for network use.

BSF

Binding Support Function

Stores and supplies binding information linking sessions with the relevant policy function.

SCP

Service Communication Proxy

Supports indirect service-based communication, routing and resilience between network functions.