Question: In 3GPP System Architecture Evolution (SAE), what modes of mobility involve specific security interworking requirements between 3GPP and non-3GPP access networks?
Option 1: Only Handover Mode
Option 2: Just during Initial Attachment
Option 3: Exclusively in Dedicated Bearer Activation
Option 4: Both Idle Mode and Active Mode
Explanation: The correct answer is Option 4 because, as per the security aspects of non-3GPP accesses in SAE, both idle mode (when the UE is not actively transmitting or receiving data) and active mode (when the UE is engaged in data transmission or reception) mobility scenarios necessitate specific security interworking measures to ensure seamless and secure handovers between 3GPP (e.g., LTE, 5G) and non-3GPP access networks (e.g., Wi-Fi, Ethernet). This dual-mode consideration is crucial for maintaining the integrity of the network and protecting user data during all phases of connectivity.