MSC
Definition
Mobile Switching Centre, the GSM core node that routes calls and SMS between the cellular network and the PSTN, and queries the HLR and VLR for subscriber state.
- Full name
- Mobile Switching Centre
- Network
- GSM core network
- Function
- Routes calls and SMS to PSTN
- Queries
- HLR and VLR for subscriber state
Common questions
Why is the MSC relevant to call detail record requests?+
The MSC is the node that actually switches and logs call and SMS events, so the call detail records forensic investigators request from a carrier are generated from MSC switching logs, making MSC records the primary source for reconstructing call timing and cell association.
How does the MSC's role differ from the HLR's role?+
The HLR is a database storing permanent subscriber information and current location area, while the MSC is the active switching node that performs call routing and queries the HLR and VLR in real time to determine how to connect a call or message.
Is the MSC still relevant in newer 4G and 5G networks?+
The MSC is specific to GSM/2G and 3G circuit-switched voice architecture; 4G LTE and 5G networks use different core elements such as the MME and AMF for equivalent functions, though many carriers still maintain MSC infrastructure for legacy 2G/3G interoperability.
Related terms
- EPC / 5GC
- Evolved Packet Core (LTE) and 5G Core (5G NR), the all-IP packet cores that replaced the circuit-switched GSM core. 5GC is service-based,...
- ICCID
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- IMEI
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- IMSI
- International Mobile Subscriber Identity. A 15-digit number stored in EF_IMSI on the SIM that uniquely identifies the subscriber account on the mobile...
- Ki
- The 128-bit secret authentication key stored on the SIM and in the operator's Authentication Centre (AuC). Never leaves either party in cleartext...