OFMON: An Adaptive Flow Monitoring Framework for SDN

Software-defined networking introduces the possibility of building self-tuning networks that constantly monitor network conditions and react rapidly to important events such as congestion. However, it is not an easy task to monitor network status without any overhead. Traditional monitoring mechanisms may introduce huge overheads when monitoring the network continuously. In this paper, we present OFMON - an adaptive flow measurement framework to reduce the overhead and improve the accuracy. It utilizes the Packet-In and Flow-Removed messages as a passive method and uses an adaptive polling algorithm based on fuzzy logic as an active method to obtain traffic metrics. The adaptive techniques are significantly more flexible in their ability of dynamically adjusting the interval of polling depending on the fluctuations of flow, which find a balance between accuracy and overhead. The experiments illustrate that OFMON provides a better method to monitor the link utilization with higher accuracy and lower overhead.