How to enable BBR on AlmaLinux 8

BBR stands for Bottleneck Bandwidth and Round-trip propagation time (RTT), which is a congestion control algorithm. Enabling TCP BBR on your Linux desktop can enhance your web browsing experience significantly. By default, Linux employs Reno and CUBIC as its congestion control algorithms.

Requirements: To use BBR, your system needs to be running on Linux kernel version 4.9 or higher. Given that AlmaLinux 8 is equipped with kernel version 4.18.0, it’s compatible for enabling BBR immediately.

To check the congestion control algorithms available on your system, execute the following command:

sysctl net.ipv4.tcp_available_congestion_control

Expected output:

root@vps:~# sysctl net.ipv4.tcp_available_congestion_control net.ipv4.tcp_available_congestion_control = reno cubic

To ascertain the current congestion control algorithm being utilized, run:

sysctl net.ipv4.tcp_congestion_control

Expected output:

[root@vps ~]# sysctl net.ipv4.tcp_congestion_control net.ipv4.tcp_congestion_control = reno cubic

Enabling TCP BBR in AlmaLinux: To enable TCP BBR, you need to edit the system’s configuration file. Open /etc/sysctl.conf using a text editor like vi:

vi /etc/sysctl.conf

Append these lines at the end of the configuration file:

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

After saving the file, apply the changes by executing:

sysctl -p

Expected output:

[root@vps ~]# sysctl -p net.core.default_qdisc = fq net.ipv4.tcp_congestion_control = bbr

To verify that BBR is now enabled on your system, use:

sysctl net.ipv4.tcp_congestion_control

Expected output:

[root@vps ~]# sysctl net.ipv4.tcp_congestion_control net.ipv4.tcp_congestion_control = bbr

And that’s it, you’re done!