Limit download and upload speed
Throttle one application to a set number of kilobytes per second and it gets no more than that. The two directions are separate, so you can give it a fast download and a hopeless upload - which is exactly what most home and mobile connections look like.
In the window
- Set Process to your application.
- Fill Download, Upload or both, in KB/s. Leave a field at 0 to leave that direction alone.
- Press START.
BeanNetworkTester.exe --down 128 --up 32 --target myapp.exe --duration 120What the numbers mean
| KB/s | Roughly | What it is |
|---|---|---|
| 6 | 56 kbit/s | A dial-up modem. The "56k modem" profile. |
| 128 | 1 Mbit/s | In-flight WiFi, a busy hotel, a bad mobile signal. |
| 1024 | 8 Mbit/s | A modest home line. Enough for one video stream. |
| 12800 | 100 Mbit/s | A normal fixed connection today. |
Kilobytes, not kilobits - so multiply by eight to compare with what an internet provider advertises. Throttling both directions at once is what makes a connection feel like a bad hotspot rather than merely a slow download.
The queue matters as much as the limit
A speed limit needs somewhere to put the packets that do not fit yet. That is the Buffer setting, in milliseconds, and it behaves like the queue at a checkout:
- A short queue means packets get thrown away as soon as the line is full. Your app sees loss and reacts quickly.
- A long queue means nothing is thrown away, but everything waits. Your app sees the connection getting slower and slower instead of failing - the effect a congested home line has, and the reason a video call degrades while a download keeps going.
The "Congested home link (bufferbloat)" profile is exactly this: a limit with a long queue. Try the same speed with a short queue and a long one, and watch how differently the app behaves.
One thing to expect
With a limit running, the counter for dropped packets can stay at zero. That is not a bug: a limit first makes packets wait, and it only drops them when the queue is genuinely full. Give it a small buffer and the drops appear.