Question: In GERAN Iu-mode for UTRAN's Initial UE Message procedure, what is the primary purpose of including the GERAN Classmark Information Element (IE) in the INITIAL UE MESSAGE message when establishing a signalling connection towards the CS domain?
Option 1: To provide the Radio Access Network (RAN) with LTE-specific capabilities.
Option 2: To facilitate handover from UTRAN to GERAN.
Option 3: To supply the Core Network (CN) with GERAN-specific information for successful operation.
Option 4: To initiate a voice call setup in the PS domain.
Explanation: The correct answer is Option 3 because, as specified, the inclusion of the GERAN Classmark IE in the INITIAL UE MESSAGE message is to provide the Core Network (CN) with specific information related to GERAN (GSM/EDGE Radio Access Network) when a signalling connection towards the CS (Circuit Switched) domain is being established. This ensures the CN has all necessary details for the successful operation of the Initial UE Message procedure in GERAN Iu-mode, highlighting its importance in interoperability and network efficiency.