Periodic broadcast and patching services - implementation, measurement and analysis in an internet streaming video testbed

Abstract.

Multimedia streaming applications can consume a significant amount of server and network resources. Periodic broadcast and patching are two approaches that use multicast transmission and client buffering in innovative ways to reduce server and network load, while at the same time allowing asynchronous access to multimedia streams by a large number of clients. Current research in this area has focussed primarily on the algorithmic aspects of these approaches, with evaluation performed via analysis or simulation. In this paper, we describe the design and implementation of a flexible streaming video server and client test bed that implements both periodic broadcast and patching, and explore the issues that arise when implementing these algorithms using laboratory and internet-based test beds. We present measurements detailing the overheads associated with the various server components (signaling, transmission schedule computation, data retrieval and transmission), the interactions between the various components of the architecture, and the overall end-to-end performance. We also discuss the importance of an appropriate server application-level caching policy for reducing the needed disk bandwidth at the server. We conclude with a discussion of the insights gained from our implementation and experimental evaluation.