Virsh Interface at Guest

Lan Bridge own definition

<interface type='network'>
      <mac address='52:54:00:dd:1d:0e'/>
      <source network='lan'/>
      <model type='rtl8139'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>

Lan Bridge external Bridge

<interface type='bridge'>
      <mac address='52:54:00:dd:1d:0e'/>
      <source bridge='lan-bridge'/>
      <model type='rtl8139'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>