SliceTime: a platform for scalable and accurate network emulation

Network emulation brings together the strengths of network simulation (scalability, modeling flexibility) and real-world software prototypes (realistic analysis). Unfortunately network emulation fails if the simulation is not real-time capable, e.g., due to large scenarios or complex models. So far, this problem has generally been addressed by providing massive computing power to the simulation, which is often too costly or even infeasible. In this paper we present SliceTime, our platform for scalable and accurate network emulation. It enables the precise evaluation of arbitrary networking software with event-based simulations of any complexity by relieving the network simulation from its real-time constraint. We achieve this goal by transparently matching the execution speed of virtual machines hosting the software prototypes with the network simulation. We demonstrate the applicability of SliceTime in a large-scale WAN scenario with 15000 simulated nodes and show how our framework eases the analysis of software for 802.11 networks.