How many kb/s is the minimum network bandwidth that can be controlled by the VideoRoom? Has anyone studied it?

General
1

By setting the maxBitrate for webbrtc, I was able to control the network bandwidth to 5Kb/s, but I found that others could control it to 3Kb/s. I’m talking about the network uplink.
Is there a more radical solution.

RtpSender rtpSender = config.getPc().addTrack(audioTrack);
RtpParameters parameters = rtpSender.getParameters();
if (!parameters.encodings.isEmpty()) {
    parameters.encodings.get(0).maxBitrateBps = 6000;
    rtpSender.setParameters(parameters);
}