Integration of fluid-based analytical model with Packet-Level Simulation for Analysis of Computer Networks

摘要

Fluid flow analytical models have been shown to be able to capture the dynamics of TCP flows and can scale well to solving for networks with a large number of flows. However, accurate closed form solutions are not yet available for wireless networks. Traditional packet-level discrete event simulations provide accurate predictions of network behavior, but their solution time can increase significantly with the number of flows being simulated. Integration of fluid flow models with packet-level simulators appears to offer significant benefits. In this paper, we describe an approach to integrate fluid flow models into QualNet, a scalable packet-level simulator. We validate the mixed model with detailed packet-level simulations for the scenarios considered in this paper. The execution time of the mixed model is significantly impacted by the frequency with which the analytical model must be solved in response to changes in the data rate at the interface of the packet-level and analytical models. We present a time averaging approach to mitigate this impact and present the results of the resulting tradeoff between prediction accuracy and model execution time.