A base station according to the present embodiment receives, if the radio terminal is in a connected mode, via a bearer between the base station and a serving gateway, downlink data addressed to the radio terminal, from the serving gateway, and includes a controller configured to transmit the downlink data to the radio terminal. The controller does not release but maintains the bearer, if the extended DRX operation is configured to the radio terminal, when the radio terminal transitions to the idle mode. The controller receives, even if the radio terminal is in the idle mode, from the serving gateway, the downlink data addressed to the radio terminal, via the bearer, and buffers the downlink data until the downlink data is transmitted to the radio terminal.