Video on demand, video on demand or television on demand (in English: video on demand, VOD) is a television system that allows users to access multimedia content in a personalized way, thus offering them the possibility of request and view a specific film or program at the exact moment that the viewer wishes. There is, therefore, the possibility of viewing it in real time or downloading it to a device such as a computer, a digital video recorder (personal video recorder) or a portable player to view it at any time. The system contains the basic video functions, such as the option to stop the program or resume it at the client's will, move it forward and backward, put it in slow motion or pause; they are called cheat modes. In addition, VoD allows the user to have the desired program without depending on fixed programming schedules. The viewer has a wide range of programs to view or make a payment for certain programs as in the case of pay per view. The client is connected to a Video on Demand server that has an alternative system to traditional movie rentals. In disk-based streaming systems we have a need for additional processing, as separate fast forward and reverse files must be stored on hard drives. In contrast, memory-based systems can run these systems directly from RAM since you don't need additional storage. We have two possible ways of VoD distribution; the first case is through LAN, we can make a much faster distribution to users. On the other hand, if we do it through WAN, the response is slower but the scope will be much wider.