Many people who tinker with VPS servers encounter a strange phenomenon: with the same configuration and the same bandwidth, others can achieve download speeds of tens or even hundreds of MB/s, but no matter what they do, their own speeds just won’t go any higher—they’re stuck at a certain level. In fact, most of the time, the problem isn’t the bandwidth, but rather TCP Congestion Control Algorithms——The system defaults to cubic,This is an old algorithm designed for desktop networks more than a decade ago, and it struggles to handle high bandwidth-delay products (BDP).
Google's open-source BBR It was created specifically to solve this problem, and it is now a built-in module of the Linux kernel,Enable completely free, zero-performance-overhead, which often delivers immediate results in terms of faster download speeds and lower latency. In this article, we'll walk you through the most straightforward way to configure BBR on this BandwagonHost VPS so that it starts automatically at boot—all it takes is a dozen or so commands.
Let's start with the conclusion: Should you enable BBR?
- Worth a try:Especially a VPS like BandwagonHost, which can be used for downloading, watching videos, and proxy forwarding—it's practically a must-have for everyone;
- Completely free: Built into the kernel; does not modify any paid services;
- Extremely low risk:But to be on the safe side, we recommend taking a system snapshot before you begin (that way, if something goes wrong, you can roll back with a single command or a click on the control panel).
The following steps assume that you are already able to... root or sudo Log in to the system via SSH. The systems installed using BandwagonHost’s “One-Click OS Reinstallation” feature in the control panel generally meet the requirements; it’s easiest to run the commands directly in the “Root shell” on the console.
Step 1: Verify that the kernel supports BBR
BBR requires kernel version 4.9 or later. First, check your current kernel version, then verify whether the module can be loaded:
uname -r
modprobe tcp_bbr
sysctl net.ipv4.tcp_available_congestion_controlIf the following appears in the list printed on the third line tcp_bbr, which indicates that the kernel supports it; proceed directly to the next step. If not, it means the system kernel is too old (common with older 3.x versions), and standard BBR cannot be installed—for these older machines, refer to the advanced solutions at the end of this article, or simply reinstall a newer system (KVM virtual machines support custom images).
Step 2: Load the BBR module and configure it to start automatically at boot
Manually load the module and write it to /etc/modules-load.d/, so it will load automatically after a reboot, and you won't need to run `modprobe` manually:
modprobe tcp_bbr
echo 'tcp_bbr' | tee /etc/modules-load.d/bbr.confStep 3: Write the BBR configuration
BBR is typically used in conjunction with queuing algorithms fq(Fair Queue) Use them together for best results. Enter these two parameters into sysctl, and they will also start automatically at boot:
echo 'net.core.default_qdisc=fq' | tee -a /etc/sysctl.d/99-bbr.conf
echo 'net.ipv4.tcp_congestion_control=bbr' | tee -a /etc/sysctl.d/99-bbr.confStep 4: Effective immediately
No need to restart—run the following command to apply the configuration immediately:
sysctl -p /etc/sysctl.d/99-bbr.confStep 5: Verify that it is actually turned on
Confirm with two commands. See tcp_bbr 和 fq This indicates success:
sysctl net.ipv4.tcp_congestion_control
sysctl net.core.default_qdiscThe first line should output net.ipv4.tcp_congestion_control = tcp_bbr, The second line is net.core.default_qdisc = fq. Next, use a speed-testing tool or download a large file to compare—only newly established connections (reopening SSH or restarting the download) will benefit from the new algorithm; don’t use old connections for this test.
Troubleshooting Common Issues
1. I didn't see `tcp_bbr` during verification.
It's most likely that the module didn't load successfully. First, modprobe tcp_bbr, See also lsmod | grep bbr;If not, check your kernel version. If you're using an older kernel, please follow the kernel replacement or BBRplus solution at the end of this article.
2. Should I restart?
No. It takes effect immediately; it will also be automatically loaded from `modules-load.d` and `sysctl.d` upon future reboots—a one-time setup that lasts forever.
3. Will this affect other services? Are there any side effects?
Virtually none. BBR is a built-in kernel algorithm that does not alter application-layer behavior; in a few extreme low-bandwidth scenarios, the difference is negligible, but it is certainly no worse than Cubic.
This BandwagonHost server is worth setting up BBR on.
If you happen to need a VPS that can reliably run BBR and is suitable for long-term use,BandwagonHost This is a long-standing provider that "Old Wang" from the tech community has been using for years: KVM architecture, the ability to freely reinstall the operating system, a control panel with a built-in root shell—it’s very easy to get started, and the network connections (especially CN2 GIA-E) Optimized for domestic traffic. Configuration options: CN2 GIA-E High-Speed Plan (1 GB / 1 core / 1 TB), CN2 GIA Standard Plan (2 GB / 2 cores / 2 TB); data centers are located in Los Angeles, Tokyo, Amsterdam, and other cities.
For more real-world speed tests, network comparisons, and buying tips, check out this post on my tool site: Is BandwagonHost VPS Worth Buying? A Comprehensive Look at BandwagonHost’s Stability, Network Connectivity, and Target Audience;In-depth guides on purchasing and advanced kernel switching are available on our main site: In-Depth Review of BandwagonHost。
If you want to get started right away, you can visit the official website to learn about the plans and promotions: BandwagonHost Official Website (Using the referral link won't affect your price). Here are direct links to some of the packages: CN2 GIA-E High-Speed Plan · CN2 GIA Standard Plan. Some of the links in this article are affiliate links; if you place an order through them, we may earn a commission, but this will not affect your final purchase price.
Summary
Enabling BBR takes just 5 steps: Verify the kernel → Load the module → Set the module to start automatically → Configure sysctl → Apply and verify. The entire process involves just a dozen or so commands, requires no reboot, is free, and has zero side effects—making it the most cost-effective method for speeding up a VPS. If you’re running an older kernel, check out the advanced kernel replacement guide at the end of this article, or simply use BandwagonHost’s “One-Click Reinstall” to switch to a new system and then come back to enable BBR.
If you find this helpful, feel free to bookmark it. We’d also love to hear about your actual speeds after enabling BBR and how much you’re using your VPS in the comments section.
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Original article by Tech.laowang. If you wish to repost this article, please credit the source: https://techlaowang.com/en/vps-bbr-acceleration-guide/
