Question: In a 3G network, during call setup, what triggers the generation of a 'call establishment-event' for Lawful Interception purposes?
Option 1: Successful handshake between User Equipment (UE) and Base Transceiver Station (BTS)
Option 2: When the 3G MSC Server initiates contact with the subscriber's device
Option 3: Upon receipt of a call request from the Public Switched Telephone Network (PSTN)
Option 4: After authentication is completed between the UE and the Serving Network
Explanation: The correct answer, Option 2, aligns with the described process where the generation of a 'call establishment-event' is tied to the moment the 3G MSC Server attempts to reach the subscriber at the beginning of a call. This event is crucial for Lawful Interception as it marks the initiation of communication setup, providing valuable timing and connection attempt information, even if the call is not successfully established. This highlights the network's ability to monitor and report on attempted communications, which is vital for security and legal compliance purposes.