GPSI (Generic Public Subscription Identifier)

In telecom networks, the GPSI is a 5G public-facing identifier used outside the 3GPP system, typically an MSISDN or an external identifier in URI form. It is mapped to the internal SUPI by the UDM and is used by Application Functions and exposure APIs.

Categories: Core NetworkSignalingIdentity and Subscriber

GPSI 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.

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions 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 FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

To place GPSI in the wider telecom-security picture, review IAMF, MSC, Network Exposure Function (NEF), OTP Bypass Attacks, UPF and GTP-U Smuggling.

Related terms

Related topic hubs

  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • 5G NEF Security Network Exposure Function security in the 5G core.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • SS7 Firewall GSMA FS.11 category 1/2/3 SS7 message screening at the STP edge.

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