A Thesis for the Degree of Master A Hybrid Transmission Mechanism for Video-on-Demand Service in IPTV

In the recent few years, the IPTV service has been widely implemented and actively studied. Among the various IPTV services, the Video-on-demand (VoD) service, which offers watching a selected video at any time through a dedicated stream, is taking the major service portion and being increasingly deployed to the market. Currently, most of the VoD server is transmitting the videos by dedicated unicast stream for each request by generating as many numbers of streams between the clients and the requested videos. In the VoD server’s point of view, this unicast transmission is simple and makes no problem when there is enough capacity or the service request arrival rate is moderately low. However, in the real world, the video request popularity is highly skewed, so there are often concentrated requests for one particular content and burst requests in case of special events. Those cases are critical for the unicast transmission servers