22-09-2012, 03:05 PM
IPTV (Internet Protocol Television)
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What is IPTV
IPTV is Internet Protocol TV which means television services over the Internet or Internet Protocol. Many people are confused with Internet TV with IPTV. Internet TV is where movie is played all ready stored in the server. You would have seen bit torrent, online movies these are internet TV where as IPTV is the real television streamed through internet rather than through cable. This delivery of digital television is made possible by using IP over broadband connection. IPTV contain the Data, Audio and Video which is also called Triple Play. To understand how IPTV changes the business of television we need to first discuss the current business of television. The television service industry can be divided roughly into content owners and creators, content distributors, and advertisers. The owners and creators are the major networks (ABC, CBS, and so on), the cable networks (CNN, HBO, and so on), and the movie studios (otherwise known collectively as Hollywood). In general, the content owners do not sell their content directly to consumers. Instead, the content is aggregated, packaged and sold to consumers via content distributors or multichannel video program distribution (MVPD) services. Today these are primarily the local TV broadcast stations (who may be owned by the major networks), cable operators (who may own cable networks), and direct broadcast satellite (DBS) operators, namely DirecTV and EchoStar in North America.
Unicast Vs MultiCast
A unicast session is the conventional networking method two computers use to communicate with one another within private one on one environment or session. In IPTV, VOD server is best example for the Unicast. Take an example, typical IPTV network consists of VOD Server, IPTV Network and STB (Set Up box) which is connected to Television. User usually controls IPTV through the remote control which is given along with STB box. Take an example user wants see a movie, first she sends a command to through the STB to VOD server the web pages. This is the unicast only between use and VOD server. Then user finds the title of movie start purchasing that movie. It is also unicast between the user and VOD Server. The communication enables the client to control VOD Server is through RTSP (Real Time Streaming Protocol) Multicast is the process of process of single source sending to multiple destinations at single time. Using IGMP, clients are able to receive the broadcast packets and enable the routing of the broadcast stream to network. IGMP allows an individual host machine to “Join” and “leave” multicast groups by responding to queries by a mulicast capable router. MultiCast enables a video server to broadcast to a video network. It saves a tremendous amount of network bandwidth over unicast, but there is no reliability mechanism so lost packets stay lost.
Core Network:
Core network consists of fiber backbone (WAN) and various VHOs. The core network gets data from the super headend (content/headend) and delivers data to the access network. The primary purpose of the core network is to provide adequate bandwidth for all of the data and video network traffic between service areas and the national content (super headend) source The core network also provides the capability for insertion of local content (including emergency alert system, or EAS) into each service area.