Question: On which interface is the Delete Session Response message sent by the PGW to the ePDG as part of the UE/ePDG Initiated Detach with GTP procedure?
Option 1: S11
Option 2: S4
Option 3: S5/S8
Option 4: S2b
Explanation: The Delete Session Response message is sent on the S2b interface by the PGW to the ePDG as part of procedures such as UE/ePDG Initiated Detach with GTP, indicating that this interface is used for communication between the PGW and ePDG in specific scenarios.