How To Enable BBR on Ubuntu 24.04 LTS

TCP BBR (Bottleneck Bandwidth and Round-trip propagation time) is a modern congestion control algorithm developed by Google. It aims to optimize network performance by improving throughput and reducing latency, making it particularly beneficial for high-speed internet connections. With the release of Ubuntu 24.04 LTS, enabling BBR can significantly enhance your server’s performance, especially for applications that require efficient data transfer. This guide will walk you through the process of enabling BBR on Ubuntu 24.04 LTS, providing detailed instructions, troubleshooting tips, and additional resources to ensure a smooth implementation.

What is BBR?

BBR is a congestion control algorithm that dynamically adjusts the rate of data transmission based on real-time network conditions. Unlike traditional algorithms such as Reno or CUBIC, which react to packet loss as an indication of congestion, BBR estimates both the available bandwidth and round-trip time (RTT) to optimize data flow. This proactive approach allows BBR to maintain high throughput while minimizing latency, making it ideal for modern internet applications.

Developed by Google and integrated into the Linux kernel starting from version 4.9, BBR has gained popularity due to its ability to perform well in diverse network environments. It is particularly effective in scenarios involving high-bandwidth and long-distance connections, such as cloud services and content delivery networks.

Benefits of Using BBR on Ubuntu

Enabling BBR on your Ubuntu 24.04 LTS system can yield several advantages:

• Improved Network Performance: BBR can significantly increase throughput by efficiently utilizing available bandwidth.
• Lower Latency: By optimizing data transmission rates, BBR reduces delays in data transfer.
• Enhanced Handling of High Bandwidth Connections: BBR excels in environments with high bandwidth and latency, making it suitable for cloud applications.
• Better Resource Utilization: With its efficient use of network resources, BBR can lead to lower CPU usage compared to traditional algorithms.

The real-world impact of enabling BBR can be seen in web servers, cloud services, and virtual private servers (VPS), where optimized network performance translates to improved user experiences and reduced operational costs.

System Requirements

Before enabling BBR on Ubuntu 24.04 LTS, ensure that your system meets the following requirements:

• Kernel Version: You need at least Linux kernel version 4.9 or higher. Ubuntu 24.04 LTS comes with a compatible kernel by default.
• Stable Internet Connection: A reliable internet connection is essential during the process to avoid disruptions.
• Sufficient Resources: While there are no specific hardware requirements for enabling BBR, a system with adequate CPU and memory will benefit from improved performance.

Checking Your Current Kernel Version

To verify your current kernel version, follow these simple steps:

1. Open your terminal application.
2. Run the following command:

uname -r

This command will display your current kernel version. Ensure it is 4.9 or higher to proceed with enabling BBR.

Enabling BBR on Ubuntu 24.04 LTS

The process of enabling BBR on Ubuntu 24.04 LTS involves a few straightforward steps:

1. 1. Update System Packages:
      • Before making any changes, it’s good practice to update your system packages to the latest versions. Run the following commands:

sudo apt update
sudo apt upgrade

1. 2. Check Available Congestion Control Algorithms:
      • You can check which congestion control algorithms are available on your system by executing this command:

sysctl net.ipv4.tcp_available_congestion_control

This should list several algorithms including “bbr”. If “bbr” is not listed, ensure that you have the correct kernel version installed.

1. 3. Edit sysctl Configuration File:
      • You need to add configurations for BBR in the sysctl configuration file. Open this file with a text editor (e.g., nano):

sudo nano /etc/sysctl.conf

Add the following lines at the end of the file:

# Enable BBR
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr

1. 4. Apply Changes:
      • After saving the changes (press CTRL + O to save and CTRL + X to exit in nano), apply them using this command:

sudo sysctl -p

Verifying BBR Activation

Once you have enabled BBR, it’s essential to verify that it has been successfully activated. Follow these steps:

1. Run the following command to check the current congestion control algorithm in use:

sysctl net.ipv4.tcp_congestion_control

If everything has been set up correctly, this command should return “bbr”.

2. You can also check additional parameters related to BBR using this command:

sudo cat /proc/sys/net/ipv4/tcp_congestion_control

This should confirm that “bbr” is indeed active.

Troubleshooting Common Issues

If you encounter issues while enabling or verifying BBR on Ubuntu 24.04 LTS, consider the following troubleshooting tips:

• No Output for Available Congestion Control Algorithms: If running `sysctl net.ipv4.tcp_available_congestion_control` does not list “bbr”, ensure your kernel version is correct (at least 4.9). You may need to update your kernel or reinstall Ubuntu if necessary.
• Bash Errors When Editing sysctl.conf: If you receive errors while editing or applying changes in `sysctl.conf`, double-check for typos or syntax errors in the configuration lines you added.
• Bbr Not Active After Restarting: If BBR does not activate after rebooting your system, revisit the `sysctl.conf` file and ensure that your changes were saved correctly. You may also need to reapply settings manually using `sudo sysctl -p` after rebooting.
• Lack of Performance Improvement: If you do not notice any performance improvements after enabling BBR, consider testing under different network conditions or configurations. Performance can vary based on specific workloads and network setups.

Congratulations! You have successfully enabled BBR. Thanks for using this tutorial to boost network performance by enabling TCP BBR BBR on Ubuntu 24.04 LTS system. For additional help or useful information, we recommend you check the official Ubuntu website.