Power-Awareness Extensions for Network Testbeds

The escalation in power consumption of networking and communications equipment is of concern to technologists and environmentalists alike. Understanding how and when networking devices consume power is complicated by their lack of instrumentation. Furthermore, standard networking devices are not typically flexible enough to support experiments with new techniques for reducing power consumption. In this paper, we describe a set of extensions for Linux-based commodity switches that enable a wide range of power-aware experiments in laboratory testbeds. The extensions are based on the requirements for high fidelity in power measurement and in modulation of key subsystems. Our implementation includes two key capabilities: a flexible power consumption model and a traffic shaper that enable emulation of wide range of power-aware hardware and protocols. To validate our power-awareness extension and demonstrate their capabilities and utility, we built a testbed composed of simple, Linux-based switches. First, we show that the most simple configuration of our emulation extensions report power consumption consistent with what can be measured with an external power meter. Next, we conduct a series of experiments on power consumption when bandwidth is scaled directly to performance demands. Our results confirm our hypothesis that a finer grained approach yields more power savings when the transition cost is low and traffic varies.