Question: What is the purpose of the KgNB chaining performed during an intra-cell handover in a 5G system?
Option 1: To refresh the RRC and UP COUNT with respect to the gNB/ng-eNB.
Option 2: To update the UE's current KgNB for inter-cell handovers.
Option 3: To synchronize the KgNB across multiple cells in the network.
Option 4: To ensure that the KgNB is refreshed with respect to the RRC and UP COUNT after an intra-cell handover procedure.
Explanation: The correct answer is Option 4 because, according to the 3GPP specification, the KgNB chaining performed during an intra-cell handover ensures that the KgNB is re-freshed with respect to the RRC and UP COUNT after the procedure. This is essential for maintaining security in the 5G system.