Experiment-Driven Modeling of Open-Source Internet Traffic Generators

This paper is a first step toward the goal of evaluating the measurement accuracy of the interdeparture times (IDTs) provided by software traffic generators. To provide evidences of the proposed methodology, in this paper, we focus our attention on the experimental characterization of the internal generation cycle of a well-known, open source generator, namely, distributed internet traffic generator. We tested the traffic generator for different systems, and under the best possible conditions, i.e., with the minimum system load. The resulting performance may be seen as the ideal limit the generators can tend to. In this paper, we present the rationale for the activity, the underlying methodology and a set of tests aimed at highlighting the relevance of the clock resolution in the accuracy of IDT. In addition, we present a statistical model for the IDT of packets. The model allows to capture the effects of the various phenomena that affect this important generation parameter. We have also performed a set of experiments with another traffic generator to show the generalizability of the results. These results show that the contributions proposed in this paper are general and valid for a wide set of software-based traffic generators.