Dynamic proxy-assisted scalable broadcasting of videos for heterogeneous environments

Abstract

Periodic broadcasting (PB) is a scalable technique for providing video-on-demand services. It significantly reduces server I/O and backbone network bandwidth requirements at the expense of high storage space and high network bandwidth requirements for clients. Traditional protocols assume homogeneous clients with identical resources. Unfortunately, in practice clients have very different bandwidths, and these are usually insufficient to provide video-on-demand (VoD) service from a PB server. Existing work on heterogeneous clients has focused on devising broadcast schedules to cater to low-bandwidth clients, which inevitably requires an extra backbone network bandwidth between the server and the clients. In our previous work, we proposed to use proxies residing at the edge of backbone network to accommodate low bandwidth clients for PB-based VoD services. The server broadcasts a video using a PB protocol while the proxy receives and stores the data in its local buffer and broadcasts the stored data to the clients in its local network. It significantly reduces the waiting time of low-bandwidth clients without requiring any extra backbone bandwidth by using a proxy buffer and channels. However, although lots of PB protocols have been proposed, the scheme can be applied only to some old PB protocols based on a pyramid protocol. In this paper, we propose a proxy-assisted PB system that can be generally applied to almost all the existing PB protocols, by dynamically managing buffer space and channels in proxy servers. Thus, with our proposed system, PB VoD system can be optimized in terms of the resource usages in backbone networks, proxy servers, and clients, by adopting more suitable PB protocols.