Handles authentication, security, and location tracking.
Uses the Subscriber Identity Module (SIM) to store unique identity information. Security is maintained through a challenge-response authentication mechanism and over-the-air encryption using algorithms like A5.
Manages radio transmissions over the air interface (Um interface) using a combination of FDMA and TDMA . GSM – Architecture, Protocols and Services
GSM uses a layered protocol structure for communication between the mobile station and the network:
GSM provides a variety of standard services and built-in security measures: Handles authentication, security, and location tracking
A permanent database containing subscriber profiles and their last known location.
Includes features such as call forwarding, call waiting, and multi-party conferences. GSM – Architecture, Protocols and Services
A temporary database storing information for subscribers currently roaming in its area.
