Design of a Temperature-Constrained Governor to Save Energy in an Open Multi-Frequency Green Router

In the last years a new challenge turned out for both researchers and industries in telecommunications area is represented by green networks. Besides energy saving that is possible to achieve, another positive side effect of this is the reduction of the working temperature of internal components of telecommunications devices (switches, home gateway, routers, etc.). This idea is encouraging the development of routers of reduced dimensions as long as there is the knowledge that the temperature remains in a given range. For this reason the target of this paper is to propose a governor policy that provides the best trade-off between quality of service and energy saving in respect of a given target on the working temperature. More specifically, such a governor is in charge to manage the clock frequency of the Central Processor Unit (CPU) of the green router according to the traffic loading the router, varying the processing engine performance, the working temperature and the power consumption of the hardware at the same time. The proposed policy is then applied to a case study and evaluated by simulation to show how it can be used for the above purposes, and to allow green router designers to control the temperature statistics of a router and design the governor parameters to maintain the mean temperature below a given threshold.