Maestro: Balancing Fairness, Latency and Throughput in the OpenFlow Control Plane

Abstract

The fundamental feature of an OpenFlow network is that the controller is responsible for the configuration of switches for every traffic flow. This feature brings programmability and flexibility, but also puts the controller in a critical role in the performance of an OpenFlow network. To fairly service requests from different switches, to achieve low request-handling latency, and to scale effectively on multi-core processors are fundamental controller design requirements. With these requirements in mind, we explore multiple workload distribution designs within our system called Maestro. These designs are evaluated against the requirements, together with the static partitioning and static batching design found in other available multi-threaded controllers, NOX and Beacon. We find that a Maestro design based on the abstraction that each individual thread services switches in a round-robin manner can achieve excellent throughput scalability (second only to another Maestro design) while maintaining far superior and near optimal maxmin fairness. At the same time, low latency even at high throughput is achieved thanks to Maestro’s workloadadaptive request batching.