...
$ openstack network create --prividerprovider-network-type vlan --provider-physical-network physnet --provider-segmatationsegmentation_id 101 tenant101 provider_net
$ openstack subnet create --network tenantprovider_net --subnet-range 192.168.100.0/24 subnet
...
$ net_id=`neutron net-show tenantprovider_net | grep "\ id\ " | awk '{ print $4 }'`
...