If an instruction of a predetermined function is given at a device A in a network, the device A issues a notification request for inquiring whether or not it is possible to execute the function to devices B, C and D in a list of devices capable of cooperating with the device A. The device B receives the request and if the device B can not execute the function, then the device B issues a notification request including the search path of the device B to devices E, F and G included in a list of the device B. If the device B receives a response including a search path through the device E that can execute the function, from the device E, then the search path of the device B is added to the response and the response is sent to the device A.