BBR configuration guide

Check the available congestion control algorithms:

sudo sysctl net.ipv4.tcp_available_congestion_control

Expected output:

net.ipv4.tcp_available_congestion_control = reno cubic

Check the current congestion control algorithm:

sudo sysctl net.ipv4.tcp_congestion_control

Expected output:

net.ipv4.tcp_congestion_control = cubic

Create and edit /etc/sysctl.d/99-bbr.conf:

sudo nano /etc/sysctl.d/99-bbr.conf

With the following content:

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

Save and exit, then apply the configuration by running:

sudo sysctl --system

Expected output:

...
* Applying /etc/sysctl.d/99-tailscale.conf ...
...
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr

Verify the BBR kernel module is loaded:

lsmod | grep bbr

The output should be one line that contains tcp_bbr. Example:

tcp_bbr                20480  1

Verify BBR is enabled:

sudo sysctl net.ipv4.tcp_congestion_control

Expected output:

net.ipv4.tcp_congestion_control = bbr

References