Internet Protocol television (IPTV) refers to the network architecture, equipment and technologies, middleware and software platforms used to deliver standard or high-definition television (HDTV) signals, in real time, over managed communications service provider (CSP) networks. Until recently, IPTV services were a TV delivery solution for wireline CSPs over either DSL or FTTH access networks. Now, IPTV is beginning to be used by cable operators and satellite broadcasters as a means of providing additional TV channels to their subscribers. In the future, wireless-based distribution networks may be added to this list. IPTV delivery systems increasingly employ advanced video compression (AVC) technologies, such as MPEG-4 or VC-1, whereas early implementations of IPTV used MPEG-2. IPTV should be contrasted to over-the-top (OTT) Web streaming video with no quality of service (QoS) issues like buffering delays.