FS.20 (GPRS/GTP Security)

In telecommunications, GSMA FS.20 provides operator guidance on securing the GPRS Tunnelling Protocol on roaming and interconnect interfaces, including recommended GTP firewall behavior, message validation, and rate limiting against GTP-C and GTP-U abuse.

Categories: Core NetworkSignalingRoaming and Interconnect

FS.20 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 FS.20 in the wider telecom-security picture, review FS.19, GTP Firewall, GTP, GTP-C, FS.07 and MSSP.

Related terms

Related topic hubs

  • GTP Firewall GSMA FS.20 GTP-C/GTP-U screening on GRX/IPX borders.
  • GTP Security GTP-C/GTP-U threats across S5/S8, N3/N9 and GRX/IPX borders under GSMA FS.20.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • Roaming Security IPX/GRX interconnect risk, home-routed vs local-breakout, SEPP.

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