Traffic Models for Hybrid Satellite-Terrestrial Networks

Bradley A. Barrett

Doctoral Dissertation, Number: CSHCN MS 2000-1, Year: 2000, Advisor: John S. Baras

Abstract

While Hybrid Satellite-Terrestrial Networks (HSTNs) have become a popular method of providing Internet connectivity, network dimensioning and performance prediction problems in these networks—as in their terrestrial counterparts—have remain largely unsolved. A key hindrance to the resolution of these issues has been accurate, tractable traffic models. While a number of rather complex models have been proposed for terrestrial network traffic, these have not been evaluated against HSTN traffic. And further, recent studies have questioned whether these more complex models, while statistically better fits, really provide significantly better performance prediction.

We examine the question of how to model HSTN traffic for network dimensioning and performance prediction, and in particular, how far ahead into the future a traffic model can be expected to accurately function. We investigate these issues by directly comparing four of the most likely candidate statistical distributions—the exponential, log-normal, Weibull and Pareto. These distributions are fit to two key traffic parameters from real HSTN traffic traces (connection interarrival times and downloaded bytes), and their relative fits are compared using statistical techniques. We further compare traffic models built using these distributions in a simulated environment; comparing performance predictions (over a number of metrics) obtained from these models to the actual results from our real-world traffic traces.