    <interface type='bridge'>
      <source bridge='bridge1'/>
      <mac address='52:54:00:99:99:99'/>
    </interface>
    <interface type='bridge'>
      <source bridge='bridge2'/>
      <mac address='52:54:00:01:02:03'/>
    </interface>
    <interface type='network'>
      <source network='network1'/>
      <mac address='52:54:00:01:02:04'/>
    </interface>
    <interface type='network'>
      <source network='network2'/>
      <mac address='52:54:00:01:02:05'/>
    </interface>
    <interface type='network'>
      <source network='network3'/>
      <mac address='52:54:00:01:02:06'/>
    </interface>
    <interface type='network'>
      <source network='network4'/>
      <mac address='52:54:00:01:02:07'/>
    </interface>
    <interface type='network'>
      <source network='network4'/>
      <mac address='52:54:00:01:02:08'/>
    </interface>
