Patent ID: 7420979

Claim:
A VLAN server connected to a plurality of VLANs, for providing each VLAN with an application service, the VLAN server comprising: a plurality of processes for a plurality of application services; a plurality of virtual device drivers provided in association with the plurality of processes; a receiving-address change processing section for changing a destination address in data which is received from each VLAN and to which a VLAN tag is attached, according to the VLAN tag, to form a changed destination address; and a selection section for selecting one of the plurality of virtual device drivers according to the changed destination address which was changed by the receiving-address change processing section, wherein, when a process of the plurality of processes in the VLAN server receives data from a client, the receiving-address change processing section obtains an internal IP address corresponding to a VLAN tag taken out of a MAC header of a received MAC frame, changes a destination IP address of an IP header from an external IP address to the internal IP address to form a changed IP header, deletes a MAC header to generate an IP packet, and transmits the IP packet with the changed IP header to the selection section; the selection section selects a virtual device driver of the plurality of virtual device driver, corresponding to the destination IP address of the IP packet; the virtual device driver which is selected, transmits the IP packet received from the selection section, to the process; and the process, having the destination IP address and waiting for data, receives data of the IP packet and executes processing.