N8 (N8 Reference Point (AMF to UDM))

Also known as: N8 reference point, N8 interface

N8 is the 3GPP service-based reference point between the AMF and the UDM, exposing Nudm services for subscription data retrieval, registration status updates and access and mobility subscription management. It is one of the most sensitive interfaces in the 5G core because it fronts long-term subscriber data; TLS with OAuth 2.0 tokens and strict Nudm scope enforcement are required.

Categories: Core NetworkSecurity ControlsProtocols and Standards

N8 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.

Security controls span signaling firewalls (SS7/Diameter/GTP screening), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36.

To place N8 in the wider telecom-security picture, review AES, OpenSSL, N3IWF, TNGF, EAP-AKA′ and SEAF — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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