A Data Center Interconnects Calculus

For many application scenarios, interconnected data centers provide high service flexibility, reduce response time, and facilitate timely data backup. Many data center system parameters might have variant impact on the interconnection performance. Despite many studies on data center network performance, there exist few analytical work that reveal insightful knowledge with wide range of system parameters as input, especially focusing on data center interconnects (DCI). This paper creates analytical models for representative data center network architectures and provides the performance calculus aiming to apply for data center interconnects. By parameterising the number of devices, the arriving traffics, the switch link capacities, and the traffic locality, we derive the relationship among the DCI bandwidth, inter-DC latency, and these parameters. Based on this, further discussion and numerical examples investigate and evaluate the modelling and calculus from multiple angles and show the possibility how this calculus assists DC/DCI design and operation.