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SDN-based dynamic flow scheduling in optical data centers

Wavelength division multiplexing (WDM) based optical networks have been shown to be an attractive “green” solution for cloud data center networks because of its high bisection bandwidth, low power consumption and low complexity of network wiring. In addition to the circuit-switched nature of optical networks, the high degree of the optical switch and dynamic arrival of traffic flows make the problem of flow scheduling in optical data centers becomes very challenging. It has to consider not only the flow admission control but also wavelength assignment for the lightpaths. In this paper, we address the problem of flow scheduling in optical data centers. We first develop an optimization programming formulation that aims at maximizing the revenue for cloud providers in a long run. Since solving the optimization formulation is computationally prohibitive, we develop heuristic scheduling algorithms based on the congestion factor of traffic flows. We design a Software Defined Network framework that integrates the proposed algorithms to perform flow scheduling in optical data center networks. We evaluate the proposed algorithms through comprehensive simulations and compare their performance against that of a baseline algorithm. The results show that the proposed algorithms achieve good performance improvement compared to the baseline algorithm.