A STUDY ON TRANSPORT FAIRNESS OF BBR AND CUBIC IN A SHALLOW BUFFER NETWORK

Compared with the currently commonly used CUBIC congestion control algorithm, the BBR congestion control algorithm has the advantages of high throughput and low delay, and the two will coexist for a long time in the future. When BBR and CUBIC share the shallow buffer bottleneck link, the BBR flow will occupy a large amount of bandwidth, seriously affecting the normal transmission of the CUBIC flow. By studying the reasons for the aggressiveness of the BBR algorithm, the BBR-Compatible (BBR-C) algorithm is proposed. This algorithm actively discovered queue accumulation, updated the round-trip transmission delay in time, and adjusted the sending behavior when packet loss and retransmission were detected, so as to improve the transmission fairness of the bottleneck link. The experimental results show that, compared with BBR, BBR-C reduces aggression while guaranteeing transmission quality, improves the fairness of link transmission significantly, and increases the mean Jain Fairness Index by 1.5 to 1.58 times.