Hybrid Optical Switching for Data Center Networks

Current data centers networks rely on electronic switching and point-to-point interconnects. When considering future data center requirements, these solutions will raise issues in terms of flexibility, scalability, performance and energy consumption. For this reason several optical switched interconnects, which make use of optical switches and wavelength division multiplexing (WDM), have been recently proposed. However, the solutions proposed so far suffer from low flexibility and are not able to provide service differentiation. Furthermore, very few studies evaluate scalability and energy consumption and make extensive comparison with current data center networks. In this paper we introduce a novel data center network based on hybrid optical switching (HOS). HOS combines optical circuit, burst and packet switching on the same network. In this way different data center applications can be mapped to the optical transport mechanism that best suits to their traffic characteristics. Furthermore, the proposed HOS network achieves high transmission efficiency and reduced energy consumption by using two parallel optical switches; a slow and low power consuming switch for the transmission of circuits and long bursts, and a fast switch for the transmission of packets and short bursts. We consider the architectures of both a traditional data center network and the proposed HOS network and present a combined analytical and simulation approach for their performance and energy consumption evaluation. We demonstrate that the proposed HOS data center network achieves high performance and flexibility while considerably reducing the energy consumption of current solutions.