TCP BBR (Bottleneck Bandwidth and RTT.) is a TCP congestion control algorithm developed by Google. It tackles shortcomings of traditional TCP congestion control algorithms (Reno or CUBIC). According to Google, it can achieve orders of magnitude higher bandwidth and lower latency. TCP BBR is already being used on Google.com, YouTube and Google Cloud Platform and the Internet Engineering Task Force (IETF) has been standardizing this algorithm Since July, 2017.

BBR requires only changes on the sender side. If you have a Linux web server, TCP BBR can achieve faster web page downloads for your visitors.

TCP BBR is supported by Linux since kernel version 4.9. Use the following command to check your Linux kernel version.

uname -r

Once you have kernel 4.9 or above, edit sysctl.conf file.

sudo nano /etc/sysctl.conf

Add the following two line at the end of the sysctl.conf file.

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

Save and close the file. Then reload sysctl configurations.

sudo sysctl -p

Congrats! You have successfully enabled TCP BBR on your Ubuntu.

You can check the congestion control algorithm in use with:

sysctl net.ipv4.tcp_congestion_control