Statistical multiplexing gains in the presence of aggregated self-similar traffic explained using binomial distribution

Differentiated Services (DiffServ) Architecture is based on aggregation of traffic as opposed to per flow traffic. When DiffServ is used in a real time traffic environment, it is important to Study the effects of traffic aggregation on quality of service parameters. One-way delay and instantaneous packet delay variation (IPDV) are the most commonly used quality of service parameters for real time traffic. Also, fractal or self-similar nature of the Internet traffic has been identified in recent years. In this paper, we study how one-way delay and IPDV are affected by aggregation of self-similar traffic. We make quantitative comparisons of IPDV and one-way delay between aggregated self-similar traffic and exponential inter-arrival traffic, when the only traffic control at the entrance of the network is a real time traffic utilization threshold. Under these conditions, we point out that considerable statistical multiplexing gains are possible with respect to delay. Further, we bring out the notion of ??level of active sources that makes a significant impact on delay??, based on binomial distribution, to explain above statistical multiplexing gains. We also bring out that such multiplexing gains are not possible with IPDV as it is based on each flow, unlike on the aggregate as in the case of delay.