+ # VLAN config should follow the pattern of neutron ml2 network_vlan_ranges
+ # allowed patterns are <physical_network> or
+ # <physical_network>:<vlan_min>:<vlan_max>
+ # Note that for VLAN config, physnet 'datacentre:1:1000' is used for
+ # external networks by default and will be automatically added to
+ # Neutron config if the range specified here does not include datacentre.