Question: In E-UTRAN, what is the expectation regarding IP fragmentation function on S1 and X2 interfaces?
Option 1: Mandatory support for IP fragmentation in the IP layer on both S1 and X2 interfaces.
Option 2: Optional support for IP fragmentation, applicable only to the S1 interface.
Option 3: IP fragmentation is not supported on either S1 or X2 interfaces; alternative methods must be used.
Option 4: Support for IP fragmentation is conditional, based on the specific network domain's MTU configuration.
Explanation: The correct answer emphasizes that support for IP fragmentation in the IP layer is mandatory for both S1 and X2 interfaces. This ensures consistency and reliability across the E-UTRAN, accommodating various network deployments without compromising on basic functionality like fragmentation handling. This requirement highlights the importance of standardized support for fundamental network operations to maintain interoperability and performance.