Network Exposure Function (NEF)

A 5G core network function that securely exposes network capabilities and services to external application functions through APIs. NEF acts as a gateway between the 5G core and third-party applications, providing authentication, authorization, and policy enforcement for API access. NEF enables the monetization of network capabilities while maintaining security and control.

Categories: Core NetworkSignalingSecurity Controls

Network Exposure Function (NEF) in context

The mobile core carries subscriber sessions, mobility and policy. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF.

Signaling protocols carry the control-plane messages that set up calls, register subscribers and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA as top-tier telecom risk.

To place Network Exposure Function (NEF) in the wider telecom-security picture, review 5G SBA, ACL, Core Network Security Assessment, N32 Interface (5G), NRF and Hardening: each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

Related topic hubs

  • 5G NEF Security Network Exposure Function security in the 5G core.
  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.

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