Apparatus and method related to dual connectivity

A base station which communicates with a terminal apparatus over a Master Cell Group (MCG) bearer for dual connectivity, the base station comprising:

• a transmitter configured to transmit an Addition Request message to a secondary base station which communicates with the terminal apparatus over a Secondary Cell Group (SCG) bearer for the dual connectivity, the Addition Request message including a first information element, an Expected UE Behavior information element, and an inactivity timer, wherein the first information element indicates a request for the secondary base station to report information related to an activity of the terminal apparatus in a Secondary Cell Group (SCG) which is a group of serving cells associated with the secondary base station,
• wherein the first information element is different from the inactivity timer, and
• wherein the first information element does not include the inactivity timer;
• and
• a receiver configured to receive the information transmitted by the secondary base station.