Abstract

Since the early 1990s, a variety of studies have shown that network traffic, both for local- and wide-area networks, has self-similar properties. This led to new approaches in network traffic modelling because most traditional traffic approaches result in the underestimation of performance measures of interest. Instead of developing completely new traffic models, a number of researchers have proposed to adapt traditional traffic modelling approaches to incorporate aspects of self-similarity. The motivation for doing so is the hope to be able to reuse techniques and tools that have been developed in the past and with which experience has been gained. One such approach is the so-called pseudo-self-similar traffic (PSST) model. This model is appealing, as it is easy to understand and easily embedded in Markovian performance evaluation studies.

In applying this model in a number of cases, we have perceived various problems which we initially thought were particular to these specific cases. However, we recently have been able to show that these problems are fundamental to the PSST model.

In this paper we review the PSST model, validate it experimentally and discuss its shortcomings. As far as we know, this is the first paper that discusses these shortcomings formally. We also report on ongoing work to overcome some of these problems.

Author Keywords: Self-similarity; Markovian traffic models; Trace-driven simulations; Parameter fitting; Queueing; Matrix-geometric methods

Article Outline

1. Introduction

2. Self-similarity

3. The PSST model

3.1. Model definition

3.2. Computation of the parameters n, q and a

3.3. Continuous-time variant

4. Application

4.1. Fitting the PSST model to traces

4.2. The PSST model in queueing analyses

5. Formal validation

6. Alternative models and fitting procedures

7. Conclusions and outlook

Acknowledgements

References

Vitae

Corresponding author.

*1 This work was performed in the period 2000–2002 during which the first three authors were at the RWTH Aachen. R. El Abdouni Khayari and R. Sadre have been supported by the German science foundation DFG in project HA 2966/2 (“Planung moderner Kommunikationsnetze unter Berücksichtigung realitätsgetreuer Verkehrsstrukturen”).