EPS Fallback
In telecommunications, EPS Fallback is a 5G voice procedure in which a UE attached to 5G is moved to LTE (EPS) for the duration of a voice call when VoNR is not available. It allows operators to deploy 5G data while continuing to rely on VoLTE for voice.
Categories: Radio Access Network
EPS Fallback 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.
To place EPS Fallback in the wider telecom-security picture, review 1G, 2G, 5G, 5G SA, 5G NSA and 5GNR — 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.