How to enable BBR on Ubuntu 21.10
BBR stands for Bottleneck Bandwidth and RTT is a congestion control system. You can enable TCP BBR on your Linux desktop to improve the overall web surfing experience. By default, Linux uses the Reno and CUBIC congestion control algorithm.
Requirements:
- BBR requires Linux kernel version 4.9 or above. Since Ubuntu 21.04 comes with the 5.11.0 kernel, we can enable BBR right away.
Run the following command to check available congestion control algorithms,
sysctl net.ipv4.tcp_available_congestion_control
Output:
root@crowncloud:~# sysctl net.ipv4.tcp_available_congestion_control
net.ipv4.tcp_available_congestion_control = reno cubic
Run the below command to check the current congestion control algorithm used in your system,
sysctl net.ipv4.tcp_congestion_control
Output:
root@crowncloud:~# sysctl net.ipv4.tcp_congestion_control
net.ipv4.tcp_congestion_control = cubic
Enabling TCP BBR in Ubuntu
Open the following configuration file vi /etc/sysctl.conf
to enable enable TCP BBR.
vi /etc/sysctl.conf
At the end of the config file, add the following lines.
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr
Save the file, and refresh your configuration by using this command,
sysctl -p
Output:
root@crowncloud:~# sysctl -p
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr
Now, Verify if BBR is enabled in your system,
sysctl net.ipv4.tcp_congestion_control
Output:
root@crowncloud:~# sysctl net.ipv4.tcp_congestion_control
net.ipv4.tcp_congestion_control = bbr