Question: What is the primary purpose of combining the eNB UE X2AP ID with its Extension (if present) in the context of the X2 interface within an Evolved Universal Terrestrial Radio Access Network (E-UTRAN)?
Option 1: To facilitate load balancing across multiple eNodeBs.
Option 2: To uniquely identify a User Equipment (UE) over the X2 interface within an eNodeB (eNB).
Option 3: To enable priority scheduling for mission-critical communications.
Option 4: To secure X2-C signaling transport against unauthorized access.
Explanation: The correct answer highlights the key function of combining these identifiers: ensuring unique identification of a User Equipment (UE) on the X2 interface within a specific eNodeB, crucial for proper routing and management of signaling and data between eNodeBs in E-UTRAN architectures.