Question: Upon termination of an IP-CAN session, what action does the Policy and Charging Rules Function (PCRF) initiate towards the TSSF, and what is the immediate response of the TSSF?
Option 1: PCRF sends a STA command; TSSF responds with a STR command.
Option 2: PCRF sends an ADC rule update; TSSF acknowledges with a session status report.
Option 3: PCRF terminates all ongoing transactions; TSSF confirms with a session closure notification.
Option 4: PCRF sends a STR (Session Termination Request) command; TSSF acknowledges with a STA command and instantly deactivates all associated ADC rules.
Explanation: This is the correct sequence based on standard PCC procedures. The PCRF initiates session termination by sending a STR command to the TSSF. Upon receipt, the TSSF confirms the termination request with a STA (Session Termination Acknowledgement) command and immediately removes/deactivates all previously installed or activated Access Delivery Control (ADC) rules for that session, ensuring resource cleanup and policy consistency.