Description of configuration options for ml2

Configuration option=Default value	(Type) Description
flat_networks=	(ListOpt) List of physical_network names with which flat networks can be created. Use * to allow flat networks with arbitrary physical_network names.
mechanism_drivers=	(ListOpt) An ordered list of networking mechanism driver entrypoints to be loaded from the neutron.ml2.mechanism_drivers namespace.
req_timeout=30	(IntOpt) Total time limit for a cluster request
tenant_network_types=local	(ListOpt) Ordered list of network_types to allocate as tenant networks.
type_drivers=local,flat,vlan,gre,vxlan	(ListOpt) List of network type driver entrypoints to be loaded from the neutron.ml2.type_drivers namespace.
vni_ranges=	(ListOpt) Comma-separated list of <vni_min>:<vni_max> tuples enumerating ranges of VXLAN VNI IDs that are available for tenant network allocation