Optimize TCP by enabling BBR on Oracle Cloud Linux

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Introduction

BBR (“Bottleneck Bandwidth and Round-trip propagation time”) aims to improve network performance and reduce latency. BBR estimates the available network bandwidth and the round-trip time (RTT) to adjust the TCP sending rate dynamically, reducing queuing delays and reducing packet loss.

Prerequisites

Check if your Linux kernel version is 4.9 or higher.

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uname -r

Congestion Control Status

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sysctl net.ipv4.tcp_available_congestion_control

If you see net.ipv4.tcp_available_congestion_control = bbr cubic reno, then BBR is enabled. You can check it again after we enable BBR.

Enable BBR

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echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf
echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf
sudo sysctl -p

The first line enables Fair Queueing (FQ), which is a network scheduler that improves network performance by reducing latency and jitter. The second line enables BBR.

The last line reloads the configuration file for the changes to take effect.

References

Optimizing HTTP/2 prioritization with BBR and tcp_notsent_lowat:
https://blog.cloudflare.com/http-2-prioritization-with-nginx/

TCP BBR congestion control comes to GCP – your Internet just got faster:
https://cloud.google.com/blog/products/networking/tcp-bbr-congestion-control-comes-to-gcp-your-internet-just-got-faster