A Multimedia Delivery Architecture for IPTV with P2P-Based Time-Shift Support

From the four basic functionalities of video delivery systems - linear TV, video on demand (VoD), time-shifted TV (tsTV), and network personal video recorder (nPVR) - most of today´s solutions focus either on linear TV, or on VoD. While linear TV usually uses efficient distribution mechanisms such as multicast, VoD is often realized via centralized, bandwidth- inefficient unicast. Even when file sharing P2P algorithms are used for VoD or nPVR, they can not be applied to tsTV since they require the whole content to exist from the beginning. With this paper, we propose a novel solution that aims at offering all four functionalities in one distributed system. Our architecture uses multicast for the distribution of live content, and a modified P2P protocol for offering VoD, nPVR, and tsTV altogether.