Achieving statistical gains when multiplexing video streams, as in a video-on-demand (VOD) scenario, is difficult because of the stringent QOS demands and the self-similar nature of the traffic. This paper explores, through empirical simulation, the QOS, network utilization, and statistical characteristics of the aggregate traffic resulting from multiple independent MPEG video streams. In addition, the simulation results are compared against several recently-derived theoretical results for self-similar network traffic. Three main results are evident from our experiments. First, moderate statistical multiplexing gain can be achieved when multiplexing multiple self-similar streams. Second, video multiplexing is extremely sensitive to traffic phasing effects and to heavy-tailed frame size distributions. Finally, the theoretical approach considered (Norros (see IEEE Journal on Selected Areas in Communications, vol.13, no.6, p.953-62, 1995) effective bandwidth formulation) appears promising but requires fine-tuning to be practical for call admission and network dimensioning.
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