Patent ID: 8793513

Claim:
A network device comprising: a communication unit for conducting communication with a communication terminal, the communication unit being connected to the communication terminal through a network; and a processing unit that is put in a first power state and a second power state whose power consumption is smaller than that of the first power state, the processing unit being connected to the communication unit through a communication channel, the processing unit processing received data received from the communication unit when the processing unit is in the first power state, wherein the communication unit includes: a transmit-receive unit for transmitting and receiving data to and from the communication terminal through the network; a determination unit for determining the power state of the processing unit; a transition unit for outputting a transition signal for causing the power state of the processing unit to transition to the first power state, when the transmit-receive unit receives the data from the communication terminal and when the determination unit determines that the processing unit is in the second power state; and a persistent connection control unit for establishing a session with the communication terminal when the transmit-receive unit receives a session establishment request signal from the communication terminal and when the transition unit outputs a transition signal, the persistent connection control unit performing persistent connection control to prohibit the communication terminal from transmitting data while the session is maintained until the power state of the processing unit transitions to the first power state; wherein the communication unit includes a receive buffer in which received data received from the communication terminal is temporarily stored, the transmit-receive unit transmits a receivable data amount corresponding to a free space of the receive buffer to the communication terminal according to a predetermined communication protocol, and the persistent connection control unit decreases a data amount read from the receive buffer compared with non-persistent connection control such that the receivable data amount is smaller than a minimum transmittable data amount of the communication terminal until the determination unit determines that the power state of the processing unit has transitioned to the first power state.