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<p>The challenges for streaming media today include the high data rates and significant bandwidth required for the uninterrupted delivery of high-quality music and video. Building a scalable and reliable system for on-demand and live streaming in this environment has proven difficult.</p><p>By definition, a media-on-demand system lets clients freely access and play back media without interruption after a given start-up latency. The authors' system keeps the server's outgoing bandwidth independent of the number of clients, and each client behaves independently of other clients.</p><p>Although most codecs tolerate a certain amount of data loss, a high loss rate can significantly affect playback quality. Even with router assistance to aggregate acknowledgments, for a sufficiently heterogeneous network and a large enough audience, at least one client will lose almost every packet. This requires retransmission, which causes delays and results in massive reception of duplicate packets.</p><p>The authors' MoD system uses forward error correction codes to recover lost data. FEC uses the same redundant data to allow multiple clients to recover from different packet losses.</p>

S. B. Lassen, J. E. Rasmussen, P. Knudsgaard, G. B. Horn and M. Luby, "A Scalable and Reliable Paradigm for Media on Demand," in Computer, vol. 34, no. , pp. 40-45, 2001.
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