lxc-network/lxc_net/templates/network.xml

<network>
  <name>{{ name }}</name>
  <uuid>{{ uuid }}</uuid>
  <bridge name='virbr{{ bridge_id }}' stp='on' delay='0'/>
  <mac address='{{ mac }}'/>
  <domain name='{{ name }}'/>
  <ip address='{{ addrv4 }}' netmask='{{ netmaskv4 }}'>
  </ip>
  <ip family='ipv6' address='{{ addrv6 }}' prefix='{{ prefixv6 }}'>
  </ip>
</network>