How to Enable BBR on CentOS Stream 9?

Hello, friends. We already know that many home servers are deployed with CentOS 9. So by enabling BBR you will be able to get better bandwidth usage and thus improve their speed. Let’s get started.

What is BBR?

BBR (Bottleneck Bandwidth and RTT) is a congestion control algorithm written by Google software engineers. The truth is that it hasn’t been around very long, so it is relatively new.

The main goal of BBR is to initiate network utilization and reduce queuing. However, this feature should only be enabled on servers and not at the network or client level.

So, the first release of this feature was in 2016 and requires at least kernel version 4.19, so newer distributions should have no problem using it.

Enable BBR on CentOS 9 Stream

Since CentOS 9 includes a kernel version higher than 4.19 we will be able to get started without too many issues.

Before starting, update the system

sudo dnf update

Next, check the status of the congestion control algorithm on the system

sysctl net.ipv4.tcp_available_congestion_control

You should notice screen output like this

net.ipv4.tcp_available_congestion_control = reno cubic

Then check which algorithm the system is using

sysctl net.ipv4.tcp_congestion_control

Sample output

net.ipv4.tcp_congestion_control = cubic

Now let’s make the change.

To achieve this, edit the /etc/sysctl.conf file

sudo vi /etc/sysctl.conf

And at the end of the file, add these lines:

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

Save the changes and close the editor. Refresh the system configuration with this command.

sudo sysctl -p

Commit the changes by running this command

sysctl net.ipv4.tcp_congestion_control

Sample output:

net.ipv4.tcp_congestion_control = bbr

So now you know how to enable BBR on CentOS 9 Stream. With this simple trick, you can improve the bandwidth management of the system and therefore be faster.

I hope this post has helped you, and you can apply it to your system.

Also, you can do it on Debian 11