Question: In a routed mode configuration with NAT, what event triggers IP-CAN session termination initiated by the PCEF (IP Edge)?
Option 1: A device in the LAN disconnects from WLAN.
Option 2: The RG (Residential Gateway) switches off or its public IP address is released.
Option 3: A UE (User Equipment) initiates a new IP session, causing resource reallocation.
Option 4: The PCRF (Policy and Charging Rules Function) sends a session termination request to the PCEF.
Explanation: In a routed mode configuration with NAT, the IP-CAN session termination initiated by the PCEF (IP Edge) is triggered when the RG (Residential Gateway) experiences events such as switching off or having its public IP address released. This is because these events terminate the Subscriber IP session from the RG's perspective, which in turn triggers the IP-CAN session termination procedure according to the specified exceptions for PCEF-initiated termination. Events related to devices within the LAN (Option 1) do not trigger this termination for the RG's IP session. Options 3 and 4 are incorrect as they describe unrelated scenarios; Option 3 refers to a new session initiation, which is not relevant to termination, and Option 4 describes PCRF-initiated termination, not PCEF-initiated.