MSC (Mobile Switching Center)

The Mobile Switching Center is the circuit-switched core element of GSM and UMTS networks, responsible for call routing, subscriber mobility within its serving area, supplementary services, and inter-MSC handovers. The MSC integrates with the VLR, HLR, SMSC, and gateway MSCs over SS7. While modern voice traffic is migrating to IMS-based VoLTE, MSCs still carry significant 2G/3G voice and remain exposed to SS7 abuse such as call interception, illegitimate redirection, and supplementary-service manipulation.

Categories: Core NetworkSignalingIdentity and Subscriber

MSC 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 MSC in the wider telecom-security picture, review IAMF, OTP Bypass Attacks, SMS, SMSC, SRI and VoLTE — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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