An eBPF-empowered Congestion Control System with Delay Requirements
Wenqi Pan, Yuedong Xu, Chenhao Wang, Jun Hui Wu · 2024
The rapid development of new communication applications such as virtual reality and video conferencing has brought new challenges to congestion control algorithms. In particular, these applications have specific requirements in terms of delay. Meeting specific delay requirements without high throughput loss is difficult, especially in dynamic networks. In addition, it is important that the proposed congestion control algorithms can be easily deployed. In this paper, we propose a congestion control algorithm, namely TD-BBR, to meet the delay requirements of different applications. TD-BBR is built on BBR and can adapt to various network environments without high throughput loss. we employ an online algorithm based on the recursive least squares method to predict future bandwidth. We design a simple and effective algorithm to adjust the congestion window (CWND) to meet the specific delay requirements according to the value of bandwidth prediction and the distance between the current delay and the target delay. We implement a real congestion control system through extended Berkeley Packet Filter (eBPF) technology and have deployed it in the Linux kernel without recompiling the kernel. Extensive experiments show that TD-BBR can effectively meet different delay requirements in most cases, decrease the 95th percentile delay, and avoid high throughput loss compared to other congestion control algorithms,