Comment 2 for bug 1522773

you did something like this?

neutron net-create a
neutron subnet-create a 1.0.0.0/8

neutron router-create b
neutron router-create c

neutron port-create --name d a
neutron port-create --name e a

neutron router-interface-add b port=d
neutron router-interface-add c port=e