BSF (Binding Support Function)

BSF 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.

Subscriber identifiers (IMSI, SUPI, MSISDN, IMEI) are the anchor for authentication, charging, lawful interception and fraud analytics. Any protocol or interface that leaks a permanent identifier is treated as a serious privacy defect, which is why 5G introduced SUCI concealment on the air interface.

To place BSF in the wider telecom-security picture, review PDN, UPF, SBA Token Forgery, PCRF, PGW and UDR.

Related terms

• PDN
• UPF
• SBA Token Forgery
• PCRF
• PGW
• UDR
• DRP
• IAMF

Equipment

5G SBA control (NRF, SCP, NSSF, BSF, NWDAF)

• NRF
• NRF Poisoning
• NSSAI
• NSSF
• NWDAF
• S-NSSAI
• SCP

Articles in the P1 mobile network security guide

Related topic hubs

• 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
• 5G Penetration Testing Pentesting the 5G core, SBA, SEPP, and gNB interfaces.
• 5G Security Training Training on 5G core, SBA, N32, SUCI and radio security.
• 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.