Peer-Assisted Time-Shifted Streaming Systems: Design and Promises

One of the most attractive feature of IPTV is the so-called catch-up TV. It allows viewers to watch their favorite TV programs within an expanded time window. In this paper, we emphasize the challenging characteristics of catch-up TV systems that prevent known delivery systems to be used. Then, we formulate the catch-up TV as a multiple-interval graph. Based upon this modeling, we further present a Peer-Assisted Catch-Up Streaming system, namely PACUS, where a set of end users´ computers assists the server for the content delivery. We show in particular how the PACUS tracker server can be efficiently implemented for catch-up TV. We demonstrate the benefits of PACUS by simulations. We especially highlight that PACUS reduces the traffic at the server side with the advantages of lightweight and self-adaptive unstructured peer-to-peer systems. Furthermore, comparing four kinds of neighborhood selection strategies implemented on the PACUS server, the network-friendly strategy is strongly recommended to efficiently alleviate the server burden, and reduce significantly the overall network traffic generated by the catch-up TV as well.