Enable BBR in Ubuntu After 20.04

Requirements

BBR requires Linux kernel version 4.9 or above. Since Ubuntu 20.04 comes with the 5.4.0 kernel, we can enable BBR right away.

How to enable?

1. Check available congestion control algorithms

   Bash

   sysctl net.ipv4.tcp_available_congestion_control
   

   Output:

   Bash

   net.ipv4.tcp_available_congestion_control = reno cubic
   

   So, BBR is not configured.

   Run the command sysctl net.ipv4.tcp_congestion_control to see current congestion control algorithms. Output:

   Bash

   net.ipv4.tcp_congestion_control = cubic
   

2. Vim /etc/sysctl.conf to add the following configuration at the end

   Text Only

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

3. Refresh the new added configuration by using this command sudo sysctl -p

   Output:

   Bash

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

4. Check if BBR is enabled by command sysctl net.ipv4.tcp_congestion_control

   Output:

   Bash

   net.ipv4.tcp_congestion_control = bbr
   

Now, BBR is enabled. Enjoy!