Applying backpressure to balance resource usage in software-defined wireless backhauls

The expected higher complexity of upcoming 5G wireless backhauls suggests the need to evolve towards a software defined networking (SDN) paradigm to increase the degree of programmability of these networks. Within the context of software defined wireless backhaul, one important issue is the provision of an even resource consumption of both network and IT resources. Backpressure policies have shown their ability to balance resource consumption in traditional (non-SDN) wireless backhauls. This paper analyzes two use cases in which backpressure policies can be integrated in software-defined wireless backhaul to manage network and IT resources. The first use case proposes an SDN application based on a centralized backpressure policy to balance network resources in the wireless backhaul. Simulation results reveal how the granularity of routing decisions in the SDN application significantly affects the data plane performance, suggesting a trade-off between data plane performance and overload in the control plane. The second use case proposes a distributed backpressure policy to deal with the management of computing resources by balancing the processing load caused by OpenFlow (OF) switch requests among the available distributed SDN controllers. Simulation results demonstrate how a dynamic and distributed backpressure policy can balance the processing load amongst different SDN controllers, hence, leading to significant improvements with respect to static mapping policies.