Question: What is the primary purpose of sending a Criticality Diagnostics Information Element (IE) over the UTRAN Iub interface by either Node B or the Controlling RNC (CRNC)?
Option 1: To request additional network resources for enhanced user experience.
Option 2: To initiate a handover procedure to a neighboring cell.
Option 3: To report incomprehensible, missing, or logically erroneous parts of a received message.
Option 4: To acknowledge successful transmission of a signaling message.
Explanation: The Criticality Diagnostics IE serves as a feedback mechanism. When Node B or the CRNC encounters issues with a received message (e.g., incomprehension, missing elements, or logical errors), sending this IE helps in identifying and potentially resolving these problems, ensuring smoother communication across the UTRAN Iub interface.