Patent ID: 7779095

Claim:
An apparatus capable of transmitting and receiving data to and from an external device, the apparatus comprising: a first receiving unit configured to receive an address for use in communicating with the external device and information on a lease period of the address; a calculating unit configured to calculate a remaining time of the lease period based on time elapsed since reception of the address and the lease period of the address; an electric power controlling unit configured to control electric power supplied to the apparatus, wherein the apparatus is switched between a first state and a second state based on an amount of electric power being supplied; a setting unit configured to expect a time necessary for transmission of the data and to set a predetermined threshold; and a determining unit configured to determine whether the address is valid based on the lease period of the address if the apparatus is switched from the second state to the first state, wherein the determining unit determines that the address is valid if the remaining time is longer than the predetermined threshold set by the setting unit, and wherein the apparatus carries out communication with the external device using the received address if the address is valid.