Question: In a UTRAN network, when a User Equipment (UE) establishes an RRC connection for a Circuit Switched (CS) service and has at least one activated Multimedia Broadcast/Multicast Service (MBMS) bearer service, what action is taken by the Radio Network Controller (RNC)?
Option 1: The RNC directly notifies the UE of all upcoming MBMS sessions without requesting additional information.
Option 2: The RNC requests the Serving GPRS Support Node (SGSN) to authenticate the UE again for the activated MBMS bearer service.
Option 3: The RNC requests the SGSN to send the list of MBMS bearer services that the user has activated, to enable notification when an MBMS session starts.
Option 4: The RNC ignores the MBMS activation and only manages the CS service for the UE.
Explanation: This is the correct procedure as per the given context. When a UE establishes a UTRAN RRC connection for a CS service and has at least one activated MBMS bearer service, the RNC needs to know which MBMS services the user is subscribed to, in order to notify the UE when an MBMS session of those services starts. Thus, the RNC requests this information from the SGSN. This ensures seamless integration of both CS services and MBMS services for the user.