how to limit network in VM

how to limit network in virtual machine.??? i try qos in sunstone but not susseces

Have you tried to implement this?
https://docs.opennebula.io/6.0/management_and_operations/references/vnet_template.html?highlight=inbound_avg_bw#quality-of-service-attributes

In my machine it’s running well. After VM reached N bitrate (PEAK_BW), it will throttle to N AVG_BW.