Internet Protocol TV or IPTV is a system through which television, video and audio services are delivered over Internet Protocol (IP) networks such as the Internet and corporate local area networks (LANs).If you have watched videos on YouTube or caught up with your favourite TV programmes on the Internet, you will already have used forms of Internet delivered IPTV. Another form of Internet IPTV is the transmission over Telecom service provider broadband of video on demand (VoD) and broadcast TV channels. On the whole, the various forms of Internet IPTV are more suited to the needs of consumers rather than the needs of organisations owing to limitations in quality, access control and bandwidth that the Internet presents.Local-network IPTV is by contrast with Internet IPTV better suited to the needs of organisations and involves the distribution of TV, video and audio content over a local IP network such as a LAN, wireless LAN, or one implemented using high-speed Ethernet running over existing electrical mains cabling. Such networks tend not to have the delay and bandwidth limitations of the Internet and, in the case of LANs, usually have spare capacity that IPTV can utilise with considerable efficiency through the use of the type of transmission known as IP multicasting.With local-network IPTV, TV and video would be just another network service on a LAN like email, Internet access and online business applications. Terrestrial, satellite and cable broadcast TV channels accessed via gateway or headend devices can be streamed to TVs (via IPTV set-top boxes), PCs and network projectors utilising IP multicast streaming to conserve network badwidth. Other content sources include video cameras, DVD/Blu-ray players and digital signage systems.Local-network IPTV provides the means for organisations to deliver TV and video over their existing networks without the bandwidth, quality and cost limitations of Internet IPTV, at the same time also providing the capability for much greater control over access to content - by channel, by department, by individual user and so on.