SGSN (Serving GPRS Support Node)

The Serving GPRS Support Node is the 2G/3G packet-core element that handles mobility, session management, authentication, and packet routing for GPRS and UMTS subscribers, much as the MME does for 4G. It communicates with the GGSN over GTP and with the HLR over MAP. SGSNs remain in service in many networks and are exposed to GTP attacks from compromised roaming partners, requiring GTP firewalls and strict peer validation on the Gn/Gp interfaces.

Categories: Core NetworkSignalingRoaming and Interconnect

SGSN 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 SGSN in the wider telecom-security picture, review GGSN, GTP, GTP Firewall, HSS, MAP and SMS Home Routing.

Related terms

Equipment

Mobility management (MME, AMF, SGSN)

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