Question: When a PCEF receives two instances of the Granted-Service-Unit AVP (with one including a Monitoring-Time AVP) from a PCRF, what action does the PCEF take at the specified monitoring time regarding usage threshold reset?
Option 1: The PCEF retains the original usage threshold without any adjustments.
Option 2: The PCEF resets the usage threshold to zero (0) for all Granted-Service-Unit AVPs.
Option 3: The PCEF only updates the usage threshold for the first instance of the Granted-Service-Unit AVP.
Option 4: The PCEF resets the usage threshold to the value of the Granted-Service-Unit AVP that includes the Monitoring-Time AVP.
Explanation: According to the specified behavior in Policy and Charging Control (PCC), when two instances of the Granted-Service-Unit AVP are provided by the PCRF, at the monitoring time, the PCEF resets the usage threshold to the value of the Granted-Service-Unit AVP that was accompanied by the Monitoring-Time AVP, ensuring accurate tracking and management of service unit allocations.