Fair Share of Latency in Inter-Data-Center Backbone Networks

The inter-data-center backbone networks initially carried bandwidth-intensive traffic which does not have stringent latency service-level-objectives (SLOs). Fair allocation policies were used in such networks to achieve equitable distribution of bandwidth to the flows. However, these networks have started carrying traffic that is significantly tied to the end-user experience and thus have stringent latency SLOs. But, the literature lacks routing algorithms for inter-data-center backbone networks which impose latency SLOs on its traffic in addition to achieving fair allocation of bandwidth. We, therefore, introduce a concept called "fair share of latency" that involves routing traffic for different flows such that the violation of latency SLOs is minimum. We propose a linear-programming based routing algorithm for inter-data-center backbone networks that incorporates both "fair share of latency" and fair allocation of bandwidth. We also introduce latency utility curves that depict the perceived worth of different latencies to an application. Simulation results on the topologies of inter-data-center networks of Google, Microsoft, Amazon, and IBM reveal that our routing algorithm achieves significant improvement in meeting the latency SLOs of different traffic classes with a slight reduction in the fairness of bandwidth allocation.