The number of devices installed in an Authorized Domain is controlled by a master device functionality. This master devices stores ceiling values for the total number Totaljimit of devices to be installed in the AD; the total number Localjimit of devices to be installed in a local proximity with the master device and the total number Remotejimit of devices to be installed remotely from said master device. The master device also stores current values of the number Local_count of devices installed in the AD in local proximity with the master device; and the number Remote_count of devices installed in the AD remotely from said master device. When a new device is to be installed in the AD, the ceiling values are checked with respect to the current values and it is checked whether the device is in local proximity with the master device to authorize or not its installation in the AD, either locally or remotely.