Multi-Granular Optical Transport Network design with dual power state

Bandwidth utilization and management advancements of Multi-Granular Optical Transport Networks (MG-OTN) have been shown to couple with power savings through lowered port counts. In this paper, we propose energy-efficient design of MG-OTNs by adopting multiple power levels at the MG nodes. Our proposed scheme combines the advantages of a previously proposed energy-efficient design method and introducing dual power state behavior to the MG nodes. According to the proposed scheme, a node can be either in the on state where it can add, drop and forward traffic at any granularity, or in the sleep state where it can only add and drop traffic, and accordingly, it saves the switching power consumption due to pass-through traffic. Through extensive simulations, we evaluate the proposed dual power state-based MG-OTN design in terms of energy-efficiency. Numerical results confirm that for all tested traffic patterns, putting a certain number of nodes in the sleep mode can guarantee significant power savings. Furthermore, we provide information on optimal selection of the nodes that have to be put in the sleep mode. Moreover, we study the topology dependence of the proposed scheme and show that high network connectivity leads to high power savings.