Question: What is the primary purpose of the DL-CCCH-Message-NB class in E-UTRAN as defined by 3GPP specifications for RRC protocol?
Option 1: To manage uplink data transmission from UE to E-UTRAN on DCCH logical channels.
Option 2: To handle security key exchanges between the UE and E-UTRAN.
Option 3: To broadcast system information to all UEs in a cell.
Option 4: To send RRC messages from E-UTRAN to UE on the downlink CCCH logical channel, facilitating connection setup, reestablishment, and rejection.
Explanation: The correct answer is Option 4 because the DL-CCCH-Message-NB class is specifically defined for sending RRC messages over the downlink Common Control Channel (CCCH) from the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) to the User Equipment (UE). This includes crucial connection management messages like setup, reestablishment, and rejection, which are essential for initiating and maintaining UE connectivity. The other options either refer to different logical channels (Option 1), unrelated procedures (Option 2), or a different type of information dissemination (Option 3).