BGCF (Breakout Gateway Control Function)

Also known as: Breakout Gateway Control Function

BGCF selects the network in which breakout to a circuit-switched or external IP network occurs for a SIP session that leaves the IMS. It picks either a local MGCF for CS breakout or another BGCF in a peer network, and applies routing policies including emergency and least-cost routing. Security-relevant BGCF configuration ensures that IMS sessions cannot be diverted to unauthorised breakout paths, which is a common IRSF and Wangiri-style fraud vector.

Categories: Roaming and InterconnectFraudInternet and Routing

BGCF in context

Roaming and interconnect are where two operators exchange signaling and user-plane traffic. Trust boundaries here are the primary attack surface for location tracking, SMS interception and fraud, which is why GSMA now mandates SEPP with PRINS on 5G interconnect.

Telecom fraud costs operators an estimated $40+ billion per year. Common vectors include IRSF, Wangiri callback scams, SIM box bypass, PBX hacking and A2P grey routing.

To place BGCF in the wider telecom-security picture, review Bypass Fraud, Refile, Traffic Pumping, Grey Route, Toll Fraud and SIM Box: each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

Related topic hubs

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.