Abstract: Problem to be Solved: A subject matter is to understandably make one drawing for a logical structure diagram and a physical structure diagram. Means to Solve the Problems: A physical connection between a router 10 and a switch 11 is expressed by drawing a connecting line A from circles (outer circles) indicative of the router 10 and the switch 11. By connecting between an outer circle and an intermediate circle/an inner circle with connecting lines, a logical connection between the router 10 and the switch 11, and one inside the switch 11, can be expressed.