High-fidelity switch models for software-defined network emulation

Software defined networks (SDNs) depart from traditional network architectures by explicitly allowing third-party software access to the network's control plane. Thus, SDN protocols such as Open-Flow give network operators the ability to innovate by authoring or buying network controller software independent of the hardware. However, this split design can make planning and designing large SDNs even more challenging than traditional networks. While existing network emulators allow operators to ascertain the behavior of traditional networks when subjected to a given workload, we find that current approaches fail to account for significant vendor-specific artifacts in the SDN switch control path. We benchmark OpenFlow-enabled switches from three vendors and illustrate how differences in their implementation dramatically impact latency and throughput. We present a measurement methodology and emulator extension to reproduce these control-path performance artifacts, restoring the fidelity of emulation.