A New Markov Model for Evaluating the ALR Dual-Threshold Policy

The paper proposes the analysis of the Dual-Threshold Policy, used by Adaptive Link Rate (ALR). In particular, the paper firstly presents a new Markov model of the Dual-Threshold Policy. The new features of the model concern its ability to take into account the rate switching times and the buffer size of the Ethernet Network Interface Controller (NIC). Secondly, we have evaluated the performance of the Dual-Threshold Policy by means of the proposed model and of a new power consumption model of an Ethernet NIC implementing ALR. As performance parameter, we have considered the power savings, the packet loss probability, the mean packet delay, and the oscillation of link data rate. The results show that high rate switching times can make ALR unprofitable and that the current NICs buffer size is unsuitable for ALR.