debian13 bbr

Question

debian13 bbr

Accepted Answer

Debian 13 (codenamed "trixie") is the current stable release of Debian. Like its predecessors, it includes the `tcp_bbr` kernel module, allowing you to enable Google's BBR (Bottleneck Bandwidth and Round-trip propagation time) congestion control algorithm to improve network throughput and reduce latency.

### How to Enable BBR on Debian 13

You can enable BBR by loading the module and updating your `sysctl` configuration.

#### 1. Load the BBR Module
First, load the TCP BBR kernel module:
```bash
sudo modprobe tcp_bbr
```

#### 2. Configure Persistent Settings
To ensure BBR is active after a reboot, you need to set the congestion control algorithm and the packet pacing discipline in your `sysctl` configuration.

Create or edit a configuration file (e.g., `/etc/sysctl.d/99-bbr.conf`):
```bash
sudo nano /etc/sysctl.d/99-bbr.conf
```

Add the following lines to the file:
```text
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr
```

#### 3. Apply the Changes
Apply the new settings:
```bash
sudo sysctl -p /etc/sysctl.d/99-bbr.conf
```

#### 4. Verify BBR is Active
Check that BBR is currently being used:
```bash
sysctl net.ipv4.tcp_congestion_control
```
The output should return:
`net.ipv4.tcp_congestion_control = bbr`

You can also check if the module is loaded by running `lsmod | grep bbr`.

***

**Note on Versions:** While there are newer iterations of BBR (like BBRv2 or BBRv3), the stock Linux kernel typically exposes them simply as `bbr`. The standard `tcp_bbr` module in the Debian kernel provides the core BBR functionality.