Handles authentication, security, and location tracking.
Uses modified versions of LAPD (called LAP-Dm) for the air interface and SS7 protocols (MTP) for the network interface. Layer 3 (Network): Divided into three sublayers: GSM Π²Πβ Architecture, Protocols and Services
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. Handles authentication, security, and location tracking
The Global System for Mobile Communications (GSM) is the foundational standard for second-generation (2G) digital cellular networks. It was developed to provide a unified digital mobile system that facilitates seamless international roaming and secure voice and data services. GSM Π²Πβ Architecture, Protocols and Services