URBM: User-Rank-Based Management of Flows in Data Center Networks through SDN

A data center network (DCN) is composed of many servers and switches, and how to manage flows makes a great impact on its performance. The paper applies the software-defined networking technology to flow management in a fat-tree DCN with hybrid switches, where electrical switches form the network backbone, while optical switches provide fast links. Considering that flows have different ranks, we propose a user-rank-based management (URBM) scheme to improve DCN throughput and offer differentiated QoS supports to flows based on their ranks. Low-rank flows have limits on using fast links, and their users should pay extra fees. If some links become busy, URBM finds substitute paths to reroute their flows. Alternatively, it restricts bandwidth usage of flows, where high-rank flows can use more bandwidth to satisfy QoS demands. With the price elasticity of demand model, we develop a pricing method to compute extra fees for low-rank users to use fast links. Simulation results show that URBM can improve flow throughput, provide better QoS supports for high-rank users, and raise the operator’s revenue.