Subject: Mobile Communication and Computing

Topic: GSM cellular telephony-architecture and system aspects

Difficulty: Low

Relationship between the Base station and mobile switching centre

1. A mobile switching center (MSC) is the centerpiece of a network switching subsystem (NSS). The MSC is mostly associated with communications switching functions, such as call set-up, release, and routing. However, it also performs a host of other duties, including routing SMS messages, conference calls, fax, and service billing as well as interfacing with other networks, such as the public switched telephone network (PSTN).

2.The MSC is structured so that base stations connect to it, while it connects to the PSTN. Because cellphones connect to these base stations, all forms of communication, whether between two cell phones or between a cell phone and a landline telephone, travel through the MSC.

Role of EIR entity of GSM network.

1. The Equipment Identity Register (EIR) is a database that contains a list of all valid mobile equipment on the network, where its International Mobile Equipment Identity (IMEI) identifies each MS.
2. An IMEI is marked as invalid if it has been reported stolen or is not type approved.