I saw an explanation on port/export connectivity. The data is expected to be sent from env.comp1.leaf1 to env.comp2.subcomp2.leaf2.
port-to-port : leaf1’s out port is connected to its parent’s(comp1) out port
port-to-export : comp1’s out is connected to comp2’s in export
export-to-export : comp2’s in export is connected to its child’s(subcomp2) in export
export-to-imp : subcomp’s in export is connected leaf2’s in imp port
imp-to-implementation: leaf2’s in imp port is connected to its implementation, leaf2