The mobile switching center (MSC) is the primary service delivery node for GSM/CDMA, responsible for routing voice … 展开

The home location register (HLR) is a central database that contains details of each mobile phone subscriber that is authorized to use the GSM core network. There can be several logical, and physical, HLRs per … 展开

The authentication center (AuC) is a function to authenticate each SIM card that attempts to connect to the gsm core network (typically when the phone is powered on). Once the authentication is successful, the … 展开

The Visitor Location Register (VLR) is a database of the MSs (Mobile stations) that have roamed into the jurisdiction of the Mobile Switching Center (MSC) which it serves. Each main base transceiver station in the network is … 展开

EIR is a system that handles real-time requests to check the IMEI (checkIMEI) of mobile devices that come from the switching equipment (MSC, SGSN, MME). The answer contains the result of the check: … 展开

Connected more or less directly to the GSM core network are many other functions.
The billing center is responsible for processing the toll tickets generated by the VLRs and HLRs and generating a bill for each subscriber… 展开