Location area identity

Each location area of a public land mobile network (PLMN) has its own unique identifier which is known as its location area identity (LAI). This internationally unique identifier is used for location updating of mobile subscribers. It is composed of a three decimal digit mobile country code (MCC), a two to three digit mobile network code (MNC) that identifies the GSM PLMN in that country, and a location area code (LAC) which is a 16 bit number thereby allowing 65536 location areas within one GSM PLMN.

The LAI is broadcast regularly through a broadcast control channel (BCCH). A mobile station recognizes the LAI and stores it in the subscriber identity module (SIM). A change of location area gives rise to a location update request.