Applying the TCP BBR algorithm to a Linux server

TCP BBR is a congestion control algorithm developed by Google.

After applying it to the YouTube network, Google said average performance improved by 4%, with improvements of more than 14% in some countries.
TCP BBR congestion control comes to GCP - your Internet just got faster

Prepare the server

Connect to the server and check the kernel version.
BBR can only be applied on version 4.9 or later.

$ uname -r
4.15.0-1043-aws

This example uses kernel version 4.15.0-1043-aws. (4.15)

If the version is below 4.9, update it.

$ sudo apt update && sudo apt upgrade

Apply BBR

Edit /etc/sysctl.conf.

$ sudo nano /etc/sysctl.conf

Add the following lines to the end of sysctl.conf, then save it.

net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr

Apply the kernel settings from /etc/sysctl.conf.

$ sudo sysctl -p
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr

Check whether it was applied correctly.

$ sudo sysctl -a | grep -E 'bbr|fq'
net.core.default_qdisc = fq
net.ipv4.tcp_allowed_congestion_control = reno cubic bbr
net.ipv4.tcp_available_congestion_control = reno cubic bbr
net.ipv4.tcp_congestion_control = bbr