Can't create public network

I have issued the following command:

neutron net-create public --shared --provider:physical_network public --provider:network_type flat

which produced the following network dictionary passed to Contrail: {'provider:physical_network': u'public', 'updated_at': '2017-08-21T14:22:56Z', 'revision_number': 3, 'port_security_enabled': True, 'provider:network_type': u'flat', 'id': '8897cdac-7f56-4b87-a75b-219119d0d100', 'router:external': False, 'availability_zone_hints': [], 'availability_zones': [], 'ipv4_address_scope': None, 'shared': True, 'project_id': u'3b598c589eb34bceb14ef13c2a263e6c', 'status': 'ACTIVE', 'subnets': [], 'description': '', 'tags': [], 'ipv6_address_scope': None, 'provider:segmentation_id': None, 'name': u'public', 'admin_state_up': True, 'tenant_id': u'3b598c589eb34bceb14ef13c2a263e6c', 'created_at': '2017-08-21T14:22:56Z', 'mtu': 1500, 'vlan_transparent': None}.

Contrail responded with error. Log says:

2017-08-21 14:22:56.783 ERROR networking_opencontrail.ml2.mech_driver [req-4a454d3a-ef31-42bd-b4cf-903698e496c2 admin admin] Create Network Failed: BadRequest: Bad virtual_network request: Segmenation id must be configured.
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver Traceback (most recent call last):
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver File "/usr/local/lib/python2.7/dist-packages/networking_opencontrail/ml2/mech_driver.py", line 50, in create_network_postcommit
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver self.drv.create_network(context._plugin_context, network)
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver File "/usr/local/lib/python2.7/dist-packages/networking_opencontrail/drivers/contrail_driver_base.py", line 134, in create_network
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver return self._create_resource('network', context, network)
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver File "/usr/local/lib/python2.7/dist-packages/networking_opencontrail/drivers/drv_opencontrail.py", line 251, in _create_resource
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver obj_name=res_type)
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver File "/usr/local/lib/python2.7/dist-packages/networking_opencontrail/drivers/drv_opencontrail.py", line 234, in _transform_response
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver driver_base._raise_contrail_error(info, obj_name)
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver File "/usr/local/lib/python2.7/dist-packages/networking_opencontrail/drivers/contrail_driver_base.py", line 64, in _raise_contrail_error
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver raise getattr(neutron_lib_exc, exc_name)(**info)
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver BadRequest: Bad virtual_network request: Segmenation id must be configured.
2017-08-21 14:22:56.783 TRACE networking_opencontrail.ml2.mech_driver

Field provider:segmentation_id is not required by Neutron and also isn't assigned when network is created. After performing said steps network is available and operable in OpenStack, but Contrail refused to create it on its side. Attempt to provide segmentation-id leads to error:
Invalid input for operation: segmentation_id prohibited for flat provider network.