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 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 GPSI in the wider telecom-security picture, review IAMF, MSC, OTP Bypass Attacks, SMS, SMSC and SRI — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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