Enabling BBR Congestion Control Algorithm

BBR (Bottleneck Bandwidth and Round-trip propagation time) is a TCP congestion control algorithm developed by Google that can significantly improve network performance, especially in high-latency or lossy network conditions. In this guide, you will learn how to enable BBR on your SkylonHost server instance to optimize your network performance.

BBR is supported in Linux kernel version 4.9 and later. All distributions we currently offer come with a compatible kernel, so you can enable BBR without needing to upgrade your system.

To enable BBR, log in to your server via SSH and run the following commands:

echo -e "net.ipv4.tcp_congestion_control = bbr\nnet.core.default_qdisc = fq" | sudo tee -a /etc/sysctl.d/99-bbr.conf
sudo sysctl --system

You can verify BBR is enabled by running:

sysctl net.ipv4.tcp_congestion_control

Keep in mind that while BBR improves TCP performance, it does not affect UDP traffic, so applications using UDP will not benefit from BBR. Additionally, if you are trying to optimize single flow performance between endpoints with high latency, you may also want to increase your TCP buffer sizes to unlock higher throughput.