Why might Qos not work on Mikrotik?

Question

Mikrotik

There is Mikrotik 2011. I set up the rules as a test in Qos 2. 1 host with Limit-At 15Mbit, the second host - 5Mbit. Max-Limit in both cases - 30Mbps. But for some reason, the rule does not work, and if you run iperf on both hosts to external servers, the speed starts to be divided approximately equally + - (tug of war). Tariff 17mbit. The speed in the rules themselves is displayed (the flow is fixed).
Please help and give me a hint where to look.

Answer 1

QOS is a system that decides which traffic to drop and the one that has already entered it.
LimitAT, it’s not you who will have 10Mbps, but if 10Mbps arrive for you, we will definitely miss them.
In order to limit your speed, you must first make it slightly less than the incoming connection limit, otherwise you just don’t have enough traffic to drop it.