How to Enable BBR on Debian 11 / Ubuntu 22.04

Hello, friends. In this post, you will learn how to enable BBR on Debian 11 / Ubuntu 22.04. The goal is to improve the web experience.

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.

Improve Debian 11 / Ubuntu 22.04 server speed with BBR

Before starting, check the availability of the compression algorithms:

sysctl net.ipv4.tcp_available_congestion_control

Then you will get an output screen like this:

net.ipv4.tcp_available_congestion_control = reno cubic

This indicates that BBR is not enabled on the system.

Now run this command to find out which algorithm the system is using by default:

sysctl net.ipv4.tcp_congestion_control

Sample output:

net.ipv4.tcp_congestion_control = cubic

So cubic is the algorithm Debian is using. Let’s change it.

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

sudo nano /etc/sysctl.conf

At the end of the file, add these lines:

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

Save the changes, close the editor and to apply the changes run:

sysctl -p

Sample Output:

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

Finally, verify that everything is OK and that the changes have been applied.

sysctl net.ipv4.tcp_congestion_control

Output:

net.ipv4.tcp_congestion_control = bbr

And you are done.

Conclusion

Tuning Debian 11 / Ubuntu 22.04 a little is a normal thing to get the best possible performance. In this case, we have done a process that can help your server considerably.