Patent ID: 8472420

Claim:
A gateway device, comprising: a local area network (LAN) interface including a plurality of LAN ports; a processor connected to the LAN interface; and a virtual local area network (VLAN) module connected to the LAN interface and a computer; the VLAN module including a switch and a VLAN interface, the VLAN interface including a plurality of VLAN ports corresponding to the LAN ports; and an Internet Protocol (IP) header modifier connected to the VLAN module and the processor; wherein the gateway device communicates with an Internet Protocol Version 4 (IPv4) network and at least two Internet Protocol Version 6 (IPv6) networks, and all the plurality of LAN ports are classified into a plurality of port groups corresponding to the at least two IPv6 networks; when an IPv6 user device is connected to any one of the plurality of LAN ports, the processor identifies the LAN port connected to the IPv6 user device, and enables the IPv6 user device to access the IPv6 network corresponding to the port group which includes the LAN port connected to the IPv6 user device; wherein when a plurality of IPv6 user devices in the IPv4 network are respectively connected to some or all of the plurality of LAN ports, the processor identifies the LAN ports connected to these IPv6 user devices, and enables these IPv6 user device to respectively access the IPv6 networks corresponding to the port groups which include the LAN ports connected to these IPv6 user devices; wherein when a plurality of IPv6 user devices in the IPv4 network are respectively connected to some or all of the plurality of LAN ports, each of the plurality of IPv6 user device sends a Router Solicit (RS) message to the switch through the LAN port connected to the IPv6 user device; the switch adds a VLAN tag with a predetermined value corresponding to the LAN port connected to the IPv6 user device to the RS message, and transmits the RS message with the VLAN tag to the VLAN port corresponding to the LAN port connected to the IPv6 user device; wherein the IP header modifier receives the RS messages with the VLAN tags from the VLAN interface and edits the values of traffic class fields of the RS messages according to their VLAN tag values, such that each of the RS messages is in a traffic class corresponding to its VLAN tag value, and further corresponding to the LAN port that receives the RS message; and wherein the processor receives the RS messages in the edited traffic classes, detects the VLAN tag values of the RS messages according to their traffic classes, identifies and the LAN ports receiving the RS messages according to the VLAN tag values of the RS messages, and thereby identifies the LAN ports connected to the IPv6 user devices and enables the IPv6 user devices to respectively access the IPv6 networks corresponding to the port groups which include the LAN ports connected to these IPv6 user devices.