Question: What is the mandated transport protocol stack for carrying data streams over the Iu-CS interface in UTRAN?
Option 1: RTP (Real-time Transport Protocol) over UDP (User Datagram Protocol) over IP (Internet Protocol)
Option 2: TCP (Transmission Control Protocol) over IP (Internet Protocol) with SCTP (Stream Control Transmission Protocol) fallback
Option 3: MPLS (Multiprotocol Label Switching) over GRE (Generic Routing Encapsulation) tunnels
Option 4: HTTP (Hypertext Transfer Protocol) over TLS (Transport Layer Security) for secure data transfer
Explanation: The correct answer is Option 1 because the Iu-CS interface requires support for RTP over UDP over IP for transporting data streams, optimized for real-time communications crucial for UTRAN's performance in handling voice and video traffic efficiently.