The testing scenario requires two computes.

• Compute 1: it will have a VM to receive the traffic using iperf
• Compute 2: it will have several VMs (5) with max-qos applied. Only one of them will have also a min-qos rule. When sending traffic from these VMs to the server in compute 1, the VM with min-qos should keep at least the configured minimum bandwidth.

NOTE: the minimum bandwidth QoS rule only supports egress traffic. Than means the compute 2 VMs should send traffic. If "iperf" is used, be aware of setting the compute 1 VM in server mode (receive).

NOTE: in a virtualized environment, the physical bridge interface (usually enp3s0) doesn't declare the link speed (use "ethtool" or "$ ovs-vsctl list interfaces enp3s0 | grep speed"). If the available speed of the virtual interface is too high (around 25Gbps using a devnest node), the TC HTB shaping algorithm won't be able to handle the traffic. It is needed to limit the root TC class rate to a more affordable limit, for example 1Gbps. In the compute 2 node:

  $ tc class replace dev enp3s0 parent 1:0 classid 1:fffe htb rate 10Gbit ceil 1Gbit