Method of managing virtual networks using a virtual network identifier

A method of managing virtual networks in which nodes are connected to at least one of a plurality of connecting devices having a plurality of ports and having a bridging function, and in which each node is coupled to at least one of the plurality of ports, and in which the nodes are coupled to a backbone network via the connecting devices, the method comprising the steps of:

• forming groups of virtual networks selected from nodes coupled to any of the plurality of correcting devices and other nodes coupled to at least one of the backbone network and a branch line of the backbone network;
• connecting to the backbone network or the branch line thereof, a data storing device which stores MAC addresses of the nodes coupled to respective ports of the plurality of connecting devices, and which stores virtual network identifiers indicative of the groups of virtual networks;
• and
• sending, from one of the plurality of connecting devices to the data storing device, a frame including a MAC address of a node connected to one port of another one of the plurality of connecting devices, to thereby request a virtual network identifier corresponding to the node of the another connecting device and set a group of virtual networks for the one port connected to the node in accordance with the virtual network identifier provided by the data storing device.