Hybrid Optical Switching for Energy-Efficiency and QoS Differentiation in Core Networks

In the future, the Internet may ultimately be constrained by energy consumption and the capability to provide quality of service (QoS). As regards the Internet core, hybrid optical switching (HOS) is promising to provide service differentiation and reduced energy consumption in respect to current electronic switching solutions. In this paper we present a novel hybrid HOS network architecture that efficiently integrates the optical packet, burst, and circuit switching on the same network. The proposed HOS network envisages the use of two parallel switches, a slow optical switch for the transmission of circuits and long bursts, and a fast switch for the transmission of packets and short bursts. The most appropriate switching method is selected for the traffic generated by different applications and the less power consuming elements are utilized for transmission, ensuring flexibility, QoS differentiation, and low energy consumption. The HOS network is organized in an overlay model with the HOS control layer performing routing, signaling, and link management, and with the HOS forwarding layer managing the reservation of resources and data scheduling. Performance and energy efficiency of the analyzed network are assessed by means of a combined analytical and simulation approach.