Question: In a 3GPP-compliant network, when lawfully authorized for SMS over NAS, which network node is required to act as an Interception Control Element (ICE) for messaging services interception?
Option 1: Mobility Management Entity (MME)
Option 2: Serving Gateway (SGW)
Option 3: Packet Data Network Gateway (PGW)
Option 4: Home Subscriber Server (HSS)
Explanation: According to telecom security standards for lawful interception, when SMS events are detected over NAS, the MME is designated as the ICE. This ensures messaging services can be intercepted and delivered separately from other services, adhering to lawful authorization requirements. The MME's role in handling control-plane signaling makes it a critical point for intercepting SMS communications.