Abstract: Disclosed is a local area network (LAN) and, more particularly, a communication method among a plurality of virtual LANs in an identical Internet protocol (IP) subnet. If a switching router receives a broadcast packet from a source host, it transmits the broadcast packet to all the virtual LANs to which the source host is included as well as to another virtual LAN to which a destination host is included, and thus a broadcast domain can be formed through the virtual LANs on the identical IP subnet. Also, the source host and the destination host included in the different virtual LANs transmit unicast packets to the switching router, respectively, and the switching router relays the unicast packets to the corresponding hosts, thereby enabling the communication among the virtual LANs included in the identical IP subnet.