QCI (QoS Class Identifier)

QCI in context

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how the specs interlock (for example 3GPP TS 33.501 with GSMA FS.34 for 5G SBA security), is essential for both design and audit work.

Cryptography in telecom spans air-interface ciphers (A5/1, A5/3, ZUC, SNOW, NEA/NIA), transport (IPsec, TLS), and identity (AKA, 5G-AKA, EAP-AKA'). Weak or downgradeable ciphers remain a live risk on 2G/3G fallback, and post-quantum migration is now on the roadmap for interconnect and roaming keys.

To place QCI in the wider telecom-security picture, review Jitter, IR.94, SRTP, MEC, XMPP and URLLC.

Related terms

• Jitter
• IR.94
• SRTP
• MEC
• XMPP
• URLLC
• Network Slice
• WPA2

Related topic hubs

• Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.
• Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.
• LTE Security Training Training on 4G/LTE core, Diameter, NAS and RRC security.
• Tracking Area Update LTE TAU procedure and its signaling risks.

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.