HFFC: A High-Fan-Out and Flexible-Cluster Optical Network Architecture for Data Centers

A detailed examination of the traffic in production data centers (DCs) suggests a new way to build optical network architectures (ONAs). As a result, recent efforts have pursued high-fan-out and cluster-based ONAs. A high-fan-out and flexible-cluster (HFFC) ONA for DCs is proposed in this article. The HFFC architecture is made up of an optical switch and a number of clusters, with the latter consisting of a number of top-of-rack (ToR) switches. Compared to a high-fan-out, scalable, and cluster-based optical interconnect (FSCOI), the HFFC architecture solves a congestion problem by removing the FSCOI's couplers and increasing the available bandwidth between clusters. By removing the couplers, the value of fan-out can be increased. In addition, one or several clusters can constitute a flexible cluster. The flexible cluster can be tailored for diverse intra-flexible-cluster traffic. The performance of the HFFC architecture is evaluated by simulation using synthetic traffic patterns. Compared to the FSCOI architecture, our approach has better performance in various traffic scenarios. In addition, the HFFC architecture has a flexible cluster capacity, making it more suited to large-scale intra-flexible-cluster traffic.