A real-time network simulation infrastructure based on OpenVPN

We present an open and flexible software infrastructure that embeds physical hosts in a simulated network. In real-time network simulation, where real-world implementations of distributed applications and network services can run together with the network simulator that operates in real time, real network packets are injected into the simulation system and subject to the simulated network conditions computed as a result of both real and virtual traffic traversing the network and competing for network resources. Our real-time simulation infrastructure has been implemented based on Open Virtual Private Network (OpenVPN), modified and customized to bridges traffic between the physical hosts and the simulated network. We identify the performance advantages and limitations of our approach via a set of experiments. We also present two interesting application scenarios to show the capabilities of the real-time simulation infrastructure. Preprint submitted to Journal of Systems and Software 4 August 2008