5QI (5G QoS Identifier)

In telecommunications, the 5QI is a scalar value that maps to a set of 5G QoS characteristics such as resource type (GBR or non-GBR), priority level, packet delay budget, and packet error rate. It is the 5G evolution of the LTE QCI and drives radio scheduling and policy enforcement.

Categories: Radio Access NetworkSignaling

5QI in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

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 5QI in the wider telecom-security picture, review 1G, 5G SA, AMF, Base Station (BS), BTS Impersonation (Fake BTS) and Capacity Planning — 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.