IPUPS (Inter-PLMN UP Security)

Also known as: Inter-PLMN UP Security, Inter PLMN User Plane Security

IPUPS is the 5G user-plane security function co-located with the UPF at the PLMN boundary that filters GTP-U traffic between the visited and home networks. Defined in 3GPP TS 33.501, it inspects and drops malformed or unauthorised GTP-U packets crossing the N9 interface, acting as a GTP firewall for 5G roaming user plane, the counterpart to SEPP on the control plane.

Categories: Core NetworkSignalingRoaming and Interconnect

IPUPS 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 IPUPS in the wider telecom-security picture, review FS.07, FS.19, GGSN, GTP, GTP Firewall and HLR — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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.