Enable bbr in ubuntu 22.04/20.04

ubuntuBBR.md

Enable bbr in ubuntu 22.04/20.04

Requirements:

• Linux kernel version must be greater than 4.19

  to check kernel version, run uname -r. sample output:

  5.4.0-132-generic
  

• Have the CONFIG_TCP_CONG_BBR and CONFIG_NET_SCH_FQ options compiled and added to the kernel.

  to check, run sudo cat /boot/config-$(uname -r) | grep 'CONFIG_TCP_CONG_BBR'. sample output:

  CONFIG_TCP_CONG_BBR=m
  

  to check other options, run sudo cat /boot/config-$(uname -r) | grep 'CONFIG_NET_SCH_FQ'.sample output:

  CONFIG_NET_SCH_FQ_CODEL=m
  CONFIG_NET_SCH_FQ=m
  CONFIG_NET_SCH_FQ_PIE=m
  

Enable BBR

First, check if BBR is enabled on the system. To do this, run:

sysctl net.ipv4.tcp_available_congestion_control

And you will get an output screen like this:

net.ipv4.tcp_available_congestion_control = reno cubic

Another check can be done with this command:

sysctl net.ipv4.tcp_congestion_control

Sample Output:

net.ipv4.tcp_congestion_control = cubic

And to enable BBR, edit the /etc/sysctl.conf file:

sudo nano /etc/sysctl.conf

At the end of the 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:

sudo sysctl -p

Now restart the server to apply the changes.

Verify if BBR is enabled in your system:

sysctl net.ipv4.tcp_congestion_control

output:

net.ipv4.tcp_congestion_control = bbr