H ELECTRICITY
H04 ELECTRIC COMMUNICATION TECHNIQUE
H04N PICTORIAL COMMUNICATION, e.g. TELEVISION
H04N21/00 Selective content distribution, e.g. interactive television or video on demand [VOD]
H04N21/60 Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client; , e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client