Question: When requesting ADC rules during an active TDF session, what type of CC-Request does the TDF send to the PCRF via the Sd reference point, and what specific detail must it include about the cause of the request?
Option 1: UPDATE_REQUEST with Event-Trigger AVP specifying the triggering event
Option 2: INITIAL_REQUEST with Failed-Rule-Report AVP detailing the installation failure
Option 3: TERMINATE_REQUEST with Last-Rule-Status AVP for all active rules
Option 4: RECOVERY_REQUEST without requiring any specific cause detail
Explanation: According to standard telecom practices for Policy and Charging Control (PCC), when a provisioned Event Trigger is met, the Traffic Detection Function (TDF) must notify the Policy and Charging Rules Function (PCRF) with an update on the status or request for new rules. The 'UPDATE_REQUEST' type is appropriate for scenarios where existing sessions are being modified or updated based on new conditions (e.g., meeting a specific event trigger). Including the Event-Trigger AVP informs the PCRF about the specific reason for the update request, enabling precise policy decisions, aligning with efficient network management and resource allocation in telecom networks.