SBI (Service-Based Interface)

Also known as: Service-Based Interface, Service Based Interface

The SBI is the HTTP/2 REST interface over TLS that carries all inter-NF communication in the 5G Service-Based Architecture. Each 5G Network Function producer publishes its services on the SBI, and consumers invoke them after discovery via the NRF and authorisation via OAuth2 tokens. All SBI messages are JSON and defined in the 3GPP TS 29.5xx series.

Categories: Core NetworkSecurity ControlsEncryption and Cryptography

SBI in context

The mobile core is where subscriber sessions, mobility and policy live. 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. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Security controls in telecom span signaling firewalls (SS7/Diameter/GTP screening at the network edge), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both the packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36 and, in Europe, NIS2 sectoral rules.

To place SBI in the wider telecom-security picture, review N11, SCP, Inter-Network Function Authentication, OAuth2 in 5G Core, HTTP and SMPP.

Related terms

Related topic hubs

  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • SEPP Security N32-c/N32-f, PRINS, JWE and OAuth 2.0 at the 5G roaming edge.
  • Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.
  • 5G NEF Security Network Exposure Function security in the 5G core.

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.