Traffic Shaping, strange behaviour

Hi,

We use haproxy to do traffic shaping on a download service: the goal is to limit downloads to a shared bandwidth of 300Mbps.

The number of simultaneous downloads is usually around 200.

The global limitation to 300Mbps works well.

But, each flow presents a very strange profile (see the screenshot)

The flow is jerky: 1 or 2 seconds at a high flow then 30 to 40 seconds at 0Kbps

Is this normal ? Has anyone ever encountered this behavior?