Optical switching in data centers:architectures based on optical packet/burst switching

Driven by the cloud computing, Internet of things, and emerging big data applications, more stringent requirements in terms of high bandwidth, low latency, and large interconnectivity are imposed on the communications within the data centers (DC). Traditional intra-DC network based on electronic switches is organized in a hierarchical topology, which is affected by the communication bottleneck and poor power efficiency. Architectural and technological innovations are desired, in order to enable the scalable growth both in the number of connected endpoints and exchanged traffic volume.Transparent optical switching has been considered as an attractive technology in this respect, providing data-rate and data-format agnostic operations and in the meantime eliminating the power consuming transceivers as well as format-dependent interfaces. In particular, holding the promise of efficient and flexible bandwidth utilization enabled by the sub-wavelength granularity, optical packet switching (OPS) and optical burst switching (OBS) technologies have been widely investigated for intra-DC network. Besides the capabilities of single switching element, the overall performance of these networks would largely depend on the architecture comprising the optical switches. Innovative networking solutions therefore are needed, to fully deliver the potentials of the optical switches and in the meantime interconnect increasing number of compute nodes.The technologies used for implementing OPS and OBS nodes are first discussed in this chapter, based on which several optical data center network (DCN) architectures exploiting OPS and OBS are presented. Following that, the OPSquare DCN which combines the advanced optical switching technology and intelligent networking solution is reported with promising assessment results.