Discrete-Approximation of Measured Round Trip Time Distributions : A Model for Network Emulation

— Empirical evaluations to study network performance, whether in a laboratory setting or on GENI testbeds, rely heavily on measurement-based modeling of round trip times (RTTs) to emulate realistic end-to-end delays of local and metropolitan area networks. For generating realistic traffic, we studied several models to emulate RTTs. In this paper, we performed experiments on real testbeds using synthetic TCP traffic generated from measurement data from a large university campus. As a result of our study, we present the Discrete-Approximation model for RTT (DA-RTT) emulation. Using three different metrics for performance evaluation, which include queue length at routers, connection response times, and connection durations, we demonstrate that the simple DA-RTT model closely represents the per-connection RTTs in the original traffic. While these experiments were performed in our laboratory, and not using GENI infrastructure, we present this as a possible model for adoption on GENI testbeds to emulate Round Trip Time Distributions for GENI experiments.