Absolute effects of aggregation of self-similar traffic on quality of service parameters

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 appealing to study absolute effects of traffic aggregation on quality of service parameters. That is, effects are obtained when a burstiness controller such as a token bucket is not used at the entrance of the network. 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 using simulations. The only traffic control used at the entrance of the network is an aggregated real time traffic utilization threshold. Further, we bring out the notion of "level of active sources" to explain the statistical multiplexing gains observed in delay variation.