hi  all

i am a kvm , qemu  user newbie , i am  using libvirt and virsh to mange my KVM VMs , i want to  limit the network bandwidth of each VM , i come across libvirt  xml format option :

<forward mode='nat' dev='eth0'/>
  <bandwidth>
    <inbound average='1000' peak='5000' burst='5120'/>
    <outbound average='128' peak='256' burst='256'/>
  </bandwidth>

to limit the bandwidth of each vm , however i have a question how does these option applied limit on  kvm vm ?  through using of linux cgroub or its a qemu network bandwidth  limit functionality ?