Question: In a telecom network, what does the Stop-Time AVP primarily indicate in terms of timing for a user's communication session?
Option 1: The moment a user initiates a voice call in the MSC or starts a data session at the S-GW/P-GW.
Option 2: The time when a charging report is submitted to the billing system.
Option 3: The termination time of a user's session at the Serving and Packet Data Network Gateway (S-GW/P-GW) or the end of a voice call in the Mobile Switching Center (MSC).
Option 4: The scheduled time for a recurring charging event, such as a monthly subscription fee.
Explanation: The Stop-Time AVP marks the end of a session or call, crucial for calculating duration-based charges. Its value (in UTC format) synchronizes termination times across network elements like S-GW/P-GW and MSC, ensuring precise charging and session management.