Network establishment and management protocol

A system, comprising

• a plurality of networked devices (200) each having a transceiver (8) for sending and receiving network messages, the networked messages including device description messages identifying the device type of a networked device;
• wherein
• each networked device has a predetermined device type selected from a device type hierarchy having predetermined top level elements including a controller device type (52) and a basic device type (54), and at least one further level (68) of subsidiary device types depending from the basic device type and inheriting properties of higher level device types on which the subsidiary device type depends, but not including any further level of subsidiary device types depending from the controller device type;
• at least one of the networked devices is a controller device (2) with the controller device type (52);
• and
• at least one of the networked devices is a controlled device (4) with a device type of the basic device type (54) or a device type (62,64,66,) depending from the basic device type (54).

A networked device, including:

• a transceiver (8) for sending and receiving messages;
• and:
• a message handler (26,182) arranged to send or receive simple device description message of defined length, the simple device description message being in the form of a token-compressed message compressed from a human-readable message format, the message including a device type value representing the type of the other device;
• the device type value being selected from a device type hierarchy having predetermined top level elements including a controller device type (52) and a basic device type (54), and at least one further level (68) of subsidiary device types depending from the basic device type (54) and inheriting properties of higher level device types on which the subsidiary device type depends, but not including any further level of subsidiary device types depending from the controller device type (52).