Question: During the E-RAB Setup procedure, what is the primary purpose of the MME sending an E-RAB SETUP REQUEST message to the eNB, and what key information does this message typically contain for each E-RAB?
Option 1: To release UE context; containing only the Serving GW TEID.
Option 2: To setup resources on S1 and Uu for one or several E-RAB(s); containing the Serving GW TEID, QoS indicator(s), and corresponding NAS message per E-RAB.
Option 3: To establish Data Radio Bearer(s) only; including Correlation id but not QoS indicators.
Option 4: To inform about unsuccessful E-RAB setup; with E-RAB Failed to Setup list only.
Explanation: The correct answer is Option 2 because the E-RAB SETUP REQUEST message is primarily sent by the MME to initiate the setup of resources for dedicated or default E-RABs, which involves setting up S1 Bearers and Data Radio Bearers. For each E-RAB, this message crucially contains the Serving GW TEID, QoS indicators, and the corresponding NAS message to facilitate communication between the UE and the core network in the correct sequence, ensuring efficient and tailored data transmission over both the S1 interface and the Uu interface.