A Video-on-Demand Transmission Scheme for IPTV Service with Hybrid Mechanism

The video-on-demand (VoD) service over IP based network is increasingly provided with dedicated unicast stream. 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 because the server\´s capacity is limited from its initial design so it results in high service blocking probability. To cope with this problem, we propose a hybrid transmission mechanism with newly proposing "Multi-session Multicasting" algorithm and adaptive session allocation method. The multi-session multicasting algorithm enables to serve unlimited requests within a fixed boundary of the bandwidth consumption and the adaptive video allocation method enables to decide the efficient transmission method for each videos. Therefore, by transmitting highly requested videos through multi-session multicasting and normal videos with unicast, we have achieved improvement on service blocking probability.