Abstract: A network managing apparatus detects a router capable of using Telnet from among nodes in a network and causes that router to send a broadcast ping to other nodes. Each node in the network returns a ping reply to the router. The ping and the ping reply pass through a switch before arriving at their destinations. When the ping and the ping reply pass thorough the switch, the switch extracts MAC addresses of sender nodes and store them in its MAC address table. Thus, accurate topology of the network can be obtained from the MAC address table of the switch.