RingCube — An incrementally scale-out optical interconnect for cloud computing data center

• We propose a scalable all-optical interconnect for cloud computing data center.
• A distributed wavelength-based Optical Circuit Switching is employed to build a path over multiple hops.
• The wavelength allocation strategy effectively enhances the connectivity and scalability of the network.
• Several approaches are taken to ensure a fast optical path setup.
• The optical switch enables an on demand extension of the wavelength switching capacity.

With high capacity and low power consumption, the optical interconnect provides a promising solution to address the communication bottlenecks in cloud computing data centers. However, as the scale of data center keeps an explosive growth trend, the centralized optical switching architecture may suffer from scalability issues, such as the costly switching fabric, the complicated control system, and the inflexible expansion mode. A distributed optical interconnect named RingCube (kk, nn, mm) is proposed to solve this problem. By embedding hypercube into ring topology and utilizing the multi-wavelength communication strategy, the architecture realizes incremental expansion at a fine granularity, without device replacement, port reservation or network rewiring. The proposed wavelength allocation strategies effectively reduce the number of wavelengths that is necessary to overcome the high blocking ratio of Optical Circuit Switching (OCS). Moreover a modular multi-wavelength optical switch structure is designed to realize the on-demand expansion of the wavelength switching capacity. The simulation indicates that RingCube achieves considerable performance and good scalability while maintains very low cost.