Question: In an IMS (IP Multimedia Subsystem) scenario, when the PCRF/PCF decides to revoke a user's allocated QoS resources for per-session authorizations, what action is taken by the IP-CAN upon receiving this indication?
Option 1: The IP-CAN allocates additional resources to ensure uninterrupted media flow.
Option 2: The IP-CAN restricts use of IP resources, potentially by closing the gate and blocking the media flow.
Option 3: The IP-CAN notifies the UE (User Equipment) to manually terminate the session.
Option 4: The IP-CAN ignores the indication if there are ongoing sessions.
Explanation: In the context of IMS and QoS management, when the Policy and Charging Rules Function/Policy and Charging Function (PCRF/PCF) decides to revoke allocated resources, the Policy and Charging Enforcement Function (PCEF) within the IP Connectivity Access Network (IP-CAN) must enforce this decision. Restricting IP resource use by closing the gate and blocking the media flow is a direct enforcement of the PCRF/PCF's policy decision to disable media flows for per-session authorizations, ensuring alignment with the network's policy and resource allocation rules.