Designing an energy-efficient cloud network [Invited]

Cloud computing services are mainly hosted in remote data centers (DCs) where high performance servers and high capacity storage systems are located. Moving the services to distant servers can help handling the energy bottleneck of the information and communication technologies by leading to significant power savings at the local computing resources, which on the other hand increases the energy consumption of the transport network and the DCs. In this paper, we propose mixed-integer-linear-programming- (MILP-) based provisioning models to guarantee either minimum delayed or maximum power-saving cloud services where high performance DCs are assumed to be located at the core nodes of an IP-over-wavelength division multiplexing network. We further propose heuristics, namely, delay-minimized provisioning and power-minimized provisioning, each of which mimics the behavior of the benchmark MILP formulation. Through numerical results, we show that power savings can be attained at the expense of increased propagation delays. Hence, we finally propose the delay- and power-minimized provisioning (DePoMiP), which aims to minimize the propagation delay, maximize the power savings in the transport network and minimize the power consumption overhead introduced to the DCs. Simulation results verify that DePoMiP achieves low-delay and low-power provisioning in an environment which is dominated by the cloud services.