Question: When the PCRF removes the last PCC rule associated with a usage monitoring key, how does the PCEF report accumulated usage if the Charging-Rule-Report AVP was included in an RAA command?
Option 1: The PCEF includes the accumulated usage in the next CCR command with CC-Request-Type set to "INITIAL_REQUEST".
Option 2: The PCEF sends a new CCR command specifically for this purpose, with CC-Request-Type set to "UPDATE_REQUEST" and Event-Trigger set to "USAGE_REPORT".
Option 3: The PCEF waits for the next scheduled reporting interval to report the accumulated usage.
Option 4: The PCEF does not report accumulated usage in this scenario.
Explanation: This is correct because, according to the specified behavior, when the last PCC rule for a monitoring key is removed and the Charging-Rule-Report AVP was previously included in an RAA command, the PCEF must initiate a new CCR command (with UPDATE_REQUEST and USAGE_REPORT settings) to report the accumulated usage for that key. This ensures timely reporting of usage upon rule deactivation, even if it wasn’t triggered by a usage report event.