Question: During IP-CAN session termination, what action does the PCEF take regarding accumulated usage information for all relevant monitoring keys?
Option 1: The PCEF discards all accumulated usage information to free up resources.
Option 2: The PCEF sends the accumulated usage information in a CCR with 'TERMINATION_REQUEST' using defined reporting procedures.
Option 3: The PCEF only sends usage information for monitoring keys that have reached their thresholds.
Option 4: The PCEF waits for an explicit request from the PCRF to report the accumulated usage.
Explanation: Upon IP-CAN session termination, the Policy and Charging Enforcement Function (PCEF) reports the accumulated usage for all monitoring keys with enabled usage monitoring by sending a Credit Control Request (CCR) with 'TERMINATION_REQUEST', following established reporting procedures. This ensures the Policy and Charging Rule Function (PCRF) has up-to-date information for billing, resource allocation, or policy decisions, highlighting the importance of accurate and timely usage reporting in telecom networks.