RTQS: Real-time flow fairness queue scheduling policy on router devices

Abstract

Real-time flows have become an important part of modern networks, and routers are facing increasingly complex network environments. The Active Queue Management (AQM) on routers, which devote to balance the delay requirements of real-time flows and the bandwidth fairness of network traffic, has become a challenging research topic. Existing schemes mainly focus on achieving precise bandwidth allocation through flow isolation or maintain consistently short queues to control the delay of flows. However, they fail to achieve an ideal trade-off among the bandwidth fairness, the delay requirements of real-time flows, and link utilization. This problem is even more pronounced in heterogeneous networks. In this paper, we propose Real-Time flow Fairness Queue Schedule (RTQS), a novel active queue management approach, which enhances the bandwidth fairness in router-side while effectively guarantees the delay requirements of real-time flows. RTQS performs differentiated scheduling for different types of traffic by assigning packets into proper queues whose buffer size is dynamically maintained. This effectively ensures the real-time flows’ timeliness. Moreover, RTQS achieves a scalable in-network bandwidth fairness enhancement solution by using only several queues, to ensure that different congestion control algorithms can properly co-exist, even in heterogeneous networks. We develop a prototype implementation for NS-3 simulator, which is a widely used network simulator, as an open-source solution. Our experimental results illustrate that RTQS significantly improves the bandwidth fairness among flows. Compared to other advanced AQM methods, RTQS improves the Jain’s Fairness Index (JFI) by a factor ranging from 3.45% to 102.04% and reduces the queuing delay of real-time flows by 71%, mitigating the impact of delay inflation.