Internet Protocol Television (IPTV)
IPTV is a technology that delivers the digital television service that are mostly dependent on ISP as ISP provides the minimum requirement of IPTV which is the IP network. ISP not just only provide IPTV services but also VoIP and Internet access but in this section will cover IPTV only. IPTV is a better version of the traditional telephone service where it has its own advantages and disadvantages. One of the advantages of IPTV like Video on Demand (VOD) where user is able to select a movie from the ISP database and play it at that time. Due to the fact that IPTV uses the IP network, disadvantages like packet loss and delay can happen as video quality is very sensitive to it.
Quality of Service (QOS) in Internet Protocol Television (IPTV)
QOS management in IPTV are simplified compare to the QOS in the Internet. ISP is able to control the IPTV system as IPTV is a closed network. With the control of internet access links and due to that IPTV uses internet access, this would ensure the QOS of IPTV in an IPTV system. For example, the download bandwidth of a user is at least 10Mbps thus ensuring a minimum QOS level of the IPTV although the bit rate of IPTV is 5Mbps.
In a heavier data trafficking situation, there may be other internet applications (browsing the internet) running in a simple home network besides the IPTV application (watching movie over IPTV). Due to this heavy data trafficking situation, other internet applications will be competing with the IPTV application for access bandwidth and packets will be dropped thus degrading the video quality of IPTV if the total download rate is exceeded. In order to overcome this issue, IPTV traffic is given a higher priority in the network layer therefore the IPTV traffic will not be affected by other internet applications.
IPTV application used the TCP as the transport layer protocol unlike other internet applications such as HTTP, FTP and so on. Since that TCP is considered as an elastic traffic for example if the TCP detects a congestion in the network, it will decrease its data rate thus adapting to the available bandwidth in the network.