Multicast Video-on-Demand Services £ Huadong Ma Kang G. Shin College of Computer Science & Technology Real-Time Computing Laboratory Beijing University of Posts and Telecomm. Department of EECS Beijing 100876, China The University of Michigan
[email protected] Ann Arbor, MI 48109-2122, USA
[email protected] ABSTRACT distance learning, tele-shopping, news-on-demand, and medical in- The server’s storage I/O and network I/O bandwidths are the main formation service. In general, the VoD service can be characterized bottleneck of VoD service. Multicast offers an efficient means of as follows. distributing a video program to multiple clients, thus greatly im- Long-lived session: a VoD system should support long-lived ses- proving the VoD performance. However, there are many problems sions; for example, a typical movie-on-demand service usu- to overcome before development of multicast VoD systems. This ally lasts 90–120 minutes. paper critically evaluates and discusses the recent progress in devel- oping multicast VoD systems. We first present the concept and ar- High bandwidth requirements: for example, server storage I/O and chitecture of multicast VoD, and then introduce the techniques used network bandwidth requirements are 1.5 Mbps (3-10 Mbps) in multicast VoD systems. We also analyze and evaluate problems for a MPEG-1 (MPEG-2) stream. related to multicast VoD service. Finally, we present open issues on multicast VoD as possible future research directions. Support for VCR-like interactivity: a client requires the VoD sys- tem to offer VCR-like interactivity, such as the ability to play, Keywords: Quality-of-Service (QoS), scheduling, VCR-like in- forward, reverse and pause.