Patent ID: 8135014

Claim:
A Universal Plug-and-Play (UPnP)-based network system comprising: a control point which stores a unique device name (UDN) of a controlled device; and the controlled device which transmits an advertisement message including the UDN of the controlled device, wherein the control point receives the advertisement message transmitted by the controlled device and determines that the controlled device is a previously existing controlled device in the UPnP-based network system based on the stored UDN and the UDN included in the advertisement message, wherein the control point determines whether an extension header included in the advertisement message is changed, and if it is determined that the extension header is changed, the control point transmits a message requesting a description file to the previously existing controlled device, wherein the extension header comprises information on a change of a service provided by the previously existing controlled device, wherein the change of a service comprises a new service being added to the previously existing controlled device and an existing service of the previously existing controlled device being deleted, wherein the previously existing controlled device transmits the advertisement message in response to an update to the extension header.