BBR (Bottleneck Bandwidth and Round-trip propagation time) is a TCP congestion control algorithm that Google developed. It was designed to improve the performance of high-speed networks and to provide better utilization of the available bandwidth. This article will discuss how to enable BBR on Ubuntu and provide multiple examples to illustrate its usage and the theory behind each example.
Before we dive into the details, let’s briefly discuss the problem that BBR aims to solve. In traditional TCP congestion control algorithms, the sender adjusts its transmission rate based on the amount of network congestion. However, this can result in suboptimal utilization of the available bandwidth, particularly in high-speed networks where the round-trip time (RTT) is much smaller than the buffer size. BBR solves this problem by considering both the available bandwidth and the RTT in its congestion control algorithm.
Table of Contents
Step 1: Update Ubuntu
Begin updating your Ubuntu to ensure all existing packages are up to date using the “apt update” command to ensure all your system packages are up-to-date.
sudo apt update && sudo apt upgradeStep 2: Check the Current TCP Congestion Control Algorithm in Use
Before enabling BBR, it is essential to check which TCP congestion control algorithm is currently in use. This can be done by running the following command in the terminal:
sysctl net.ipv4.tcp_congestion_controlAfter executing the specified command, the output indicating the TCP congestion control algorithm currently in use should be displayed:
net.ipv4.tcp_congestion_control = cubic
The command mentioned above displays the currently active TCP congestion control algorithm on your system. It is important to note that, by default, the algorithm is typically set to “cubic.”
Step 3: Enable BBR
To enable BBR, you must modify the sysctl configuration file on your Ubuntu system. The sysctl configuration file is used to configure various kernel parameters in the Linux operating system.
To modify the sysctl configuration file, run the following command in the terminal:
sudo nano /etc/sysctl.conf
This will open the sysctl configuration file in the nano text editor.
Next, add the following lines to the sysctl configuration file:
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbrAn illustration of what the sysctl.conf file might look like based on the number of existing options:
The first line sets the default queueing discipline to fq, which is required for BBR to function correctly. The second line sets the TCP congestion control algorithm to BBR.
Save the changes to the sysctl configuration file by pressing Ctrl + O, then exit the nano text editor by pressing Ctrl + X.
Step 3: Apply the Changes
To apply the changes to the sysctl configuration file, run the following command in the terminal:
sudo sysctl -p
This command will apply the changes to the kernel parameters specified in the sysctl configuration file.
Step 4: Verify that BBR is Enabled
To verify that BBR is enabled, run the following command in the terminal:
sysctl net.ipv4.tcp_congestion_control
This command will display the current TCP congestion control algorithm in use on your system. If BBR is enabled, the output should display bbr.
net.ipv4.tcp_congestion_control = bbr
Conclusion
In conclusion, BBR (Bottleneck Bandwidth and Round-trip propagation time) is a TCP congestion control algorithm developed by Google to improve the performance of high-speed networks. BBR solves the problem of suboptimal utilization of available bandwidth in traditional TCP congestion control algorithms by considering both the available bandwidth and the round-trip time (RTT) in its congestion control algorithm.
By enabling BBR on Ubuntu, users can expect improved performance and better utilization of available bandwidth in high-speed networks.
FAQs on BBR in Ubuntu:
Q: What is BBR?
A: BBR (Bottleneck Bandwidth and Round-trip propagation time) is a TCP congestion control algorithm developed by Google to improve the performance of high-speed networks.
Q: How does BBR work?
A: BBR works by considering both the available bandwidth and the round-trip time (RTT) in its congestion control algorithm. This allows BBR to quickly increase its transmission rate to utilize the available bandwidth, resulting in improved performance.
Q: What is the problem that BBR aims to solve?
A: BBR aims to solve the problem of suboptimal utilization of available bandwidth in traditional TCP congestion control algorithms.
Q: How do I enable BBR on Ubuntu?
A: To enable BBR on Ubuntu, you need to modify the sysctl configuration file, set the default queueing discipline to fq and the TCP congestion control algorithm to BBR, apply the changes to the kernel parameters, and verify that BBR is enabled.
Q: How do I verify that BBR is enabled on Ubuntu?
A: To verify that BBR is enabled on Ubuntu, you can run the following command in the terminal: sysctl net.ipv4.tcp_congestion_control. The output should display bbr if BBR is enabled.
Q: What are the benefits of enabling BBR on Ubuntu?
A: By enabling BBR on Ubuntu, users can expect improved performance and better utilization of available bandwidth in high-speed networks.
Q: Are there any downsides to using BBR on Ubuntu?
A: BBR effectively improves the performance of high-speed networks, but it may not be suitable for all network environments. Some users have reported issues with BBR causing higher latency and reduced performance in specific scenarios.
Q: Is BBR enabled by default on Ubuntu?
A: No, BBR is not enabled by default on Ubuntu. As outlined in this article, you will need to follow the steps to modify the sysctl configuration file and enable BBR.
Q: Can I use BBR on other operating systems besides Ubuntu?
A: Yes, BBR is not limited to Ubuntu and is available for other operating systems as well.
Q: How do I know if BBR works correctly on my Ubuntu system?
A: To verify that BBR is working correctly on your Ubuntu system, you can use network performance tools such as iperf3 or netperf to measure the performance of your network.
Q: Can I use BBR with other TCP optimization techniques?
A: Yes, BBR can be used in conjunction with other TCP optimization techniques, such as TCP Fast Open and TCP Timestamps.
Q: Is BBR a new technology?
A: BBR was developed by Google and was first introduced in 2016. Although BBR is relatively new compared to other TCP congestion control algorithms, it has gained popularity due to its effectiveness in improving the performance of high-speed networks.
Q: Can BBR improve the performance of my home network?
A: The effectiveness of BBR in improving the performance of your home network will depend on various factors, such as the speed and quality of your internet connection and the devices connected to your network. However, BBR effectively improves the performance of high-speed networks, so it may also be beneficial for your home network.
Q: Is BBR compatible with all types of networks?
A: BBR has been designed to improve the performance of high-speed networks effectively. It may not be suitable for all network environments, particularly networks with high latency or limited bandwidth.
Q: Is it safe to enable BBR on Ubuntu?
A: BBR is a widely used TCP congestion control algorithm and is considered safe on Ubuntu. However, as with any change to the configuration of your system, it is recommended to make a backup of your system before enabling BBR.
Q: Can I use BBR with a VPN connection?
A: Yes, BBR can be used with a VPN connection. However, the effectiveness of BBR in improving the performance of your VPN connection will depend on various factors, such as the speed and quality of your VPN connection and the network conditions of the VPN server.
Q: Is BBR recommended for Ubuntu server installations, or does it only improve Ubuntu desktop network performance?
A: BBR is recommended for both Ubuntu server installations and desktop users. BBR has been designed to improve the performance of high-speed networks, regardless of whether it is used on a server or desktop system.
Q: What other TCP options are available besides BBR for Ubuntu?
A: Some other TCP options that may be useful to Ubuntu desktop users include CUBIC, Reno, and Westwood. These algorithms are also designed to improve the performance of high-speed networks and may provide different benefits and trade-offs compared to BBR.
Q: What is sysctl, and what is the sysctl.conf file on Ubuntu?
A: The sysctl is a tool in the Linux operating system used to configure various kernel parameters. The sysctl.conf file is a configuration file that is used by the sysctl tool to set the values of these kernel parameters. In Ubuntu, the sysctl.conf file can be used to configure parameters such as network settings, security settings, and performance settings.
