Techno-Economic Assessment of Hybrid Electrical-Optical Intra-Data Centre Networks

In this paper we study the cost-efficiencies of the deployment of hybrid Intra-data centre networks that combine electronic packet switching with optical circuit switching technologies. By using a bottom-up approach to network dimensioning, network solutions are designed for selected data centre sizes - given by the number of servers housed in the data centre - and for selected server port speeds. The total cost of network ownership (TCO) of the hybrid network is compared against packet-switched Intra-data centre networks based on leaf-spine, fat-tree and selected Facebook architectures. The results show that for large data centre sizes hybrid networks attain significant cost savings compared to the fat-tree and the Facebook solutions. The savings are caused by the introduction of optical circuit-switched fabrics which significantly reduce the costs of switches followed by savings in maintenance & reparation, energy consumption and cabling costs.