In this section, we provide definitions, discussions and networking infrastructures of the IPTV.
In this subsection we shall discuss features and applications of IPTV. IPTV has a number of features as follows:
Support for interactive TV: IPTV provides two-way communications facilities that allow service providers to deliver a complete sample of interactive TV applications. IPTV has some types of services such as live TV, high definition TV (HDTV), interactive games, and high speed Internet browsing.
Time shifting: IPTV along with a digital video recorder is used for recording and storing IPTV content for later viewing.
Personalization: IPTV supports two-way communications and permits end users to personalize their TV viewing habits by allowing them to decide what and when they want to watch a program.
Low bandwidth requirements: Instead of delivering each channel to each end user, IPTV allows service providers to only transmit the channel that the end user has requested. This significant feature allows service providers to optimally use bandwidth of their networks.
Accessible on multiple devices: Viewing of IPTV content is not limited to televisions. Consumers can use their PCs, mobile devices, and PDAs to access IPTV services (Driscol, 2008), (She et al., 2007), (Lambert et al., 2009), and (Ikeda, 2008).
The following list shows a number of IPTV applications, where each application needs different QoS requirements in order to be delivered in the best quality to end-users:
Entertainment TV services (e.g., television channel and video-on-demand).
Security (e.g., surveillance systems);
Real-time communications (e.g., video telephony, teleconferencing);
Interactive applications (e.g., interactive TV and gaming);
Internet sharing and streaming (e.g., user-created video content and web-based streaming to a desktop PC or mobile device);
Corporate training and marketing videos (Driscol, 2008), (She et al., 2007), (Ikeda, 2008).
Live video streaming (television channel) is one of the IPTV services.