Abstract: A method of setting a user-defined virtual network is disclosed. A method of setting a virtual network includes configuring a virtual network including a controller, at least one network address translation (NAT) and at least one edge node, checking an operation type of the at least one edge node, setting a tunnel between the at least one edge node based on the operation type, and performing data transmission between the at least one edge node through the set tunnel.

Abstract: Provided are methods of ensuring network continuity performed at a local gateway, a fixed gateway, and a network device. The method of ensuring network continuity performed at a local gateway includes establishing a tunnel with a fixed gateway serving as a relay between an Internet service server and the local gateway, and performing communication with the fixed gateway through the tunnel. Therefore, even when the type of an uplink signal received by a local gateway changes or the local gateway is in an uplink signal shadow area, a terminal connected to the local gateway can be provided with a seamless Internet service.

Abstract: Provided are methods of ensuring network continuity performed at a local gateway, a fixed gateway, and a network device. The method of ensuring network continuity performed at a local gateway includes establishing a tunnel with a fixed gateway serving as a relay between an Internet service server and the local gateway, and performing communication with the fixed gateway through the tunnel. Therefore, even when the type of an uplink signal received by a local gateway changes or the local gateway is in an uplink signal shadow area, a terminal connected to the local gateway can be provided with a seamless Internet service.

Abstract: Disclosed are a system for managing virtual private networks (VPNs) includes: terminals configured to transmit user data; a manager configured to transmit information for concealing networks and managing the VPNs; border gateways configured to decrypt the user data and perform a network address translation (NAT) procedure and a filtering procedure on the decrypted user data based on the information; and servers configured to receive the user data subjected to the NAT procedure and the filtering procedure, wherein the filtering procedure is a procedure discarding the user data to be transferred to the servers that are not allowed so as to allow the terminals to access only the allowed servers, the NAT procedure is a procedure changing an Internet protocol (IP) address used in a first network to an IP address used in a second network, and the first network and the second network are different networks.

Abstract: Provided is a method of establishing a user centric virtual network. The method includes: performing a first tunneling operation between a first tunnel end and an address translation device, which are connected to a first private network, and a tunnel relay device; performing a second tunneling operation between a second tunnel end and an address translation device, which are connected to a second private network, and the tunnel relay device; and performing a third tunneling operation between the tunnel relay device and an end client, wherein a virtual IP is allocated to each of the first and second tunnel ends, the address translation devices, the end client, and the tunnel relay device; and each of the first to third tunneling operations connects routing information on the virtual IP to a corresponding tunnel.

Abstract: Disclosed is a method for providing mobile virtual private network (VPN) services. An operation method of a group and tunnel manager (GTM) for providing mobile VPN services includes receiving a first message for registering information of a VPN group from a gateway, generating tunnel information between the GTM and the gateway based on the first message, and transmitting a packet based on the tunnel information. Accordingly, a private address may be used even in a mobile VPN, and therefore a VPN site may be configured even in an environment where a public address is difficult to use, or a flexible VPN site may be configured.

Abstract: In a plurality of virtual tunnel routers including a first virtual tunnel router and a second virtual tunnel router, the first virtual tunnel router and the second virtual tunnel router request virtual network prefix information from a tunnel mapping controller. When the tunnel mapping controller generates virtual network prefix information of the first virtual tunnel router and the second virtual tunnel router, respectively, and transmits the same along with information of a list of adjacent virtual tunnel routers, the first virtual tunnel router and the second virtual tunnel router create a tunnel. With the tunnel established, the virtual network prefix information received by the first virtual tunnel router and second virtual tunnel router, respectively, is linked so that direct communication can be performed between the first virtual tunnel router and the second virtual tunnel router.

Abstract: The invention relates to a method and an apparatus for controlling seamless handover between heterogeneous networks based on IPv6 over IPv4 tunneling. When IPv6 service is provided using tunneling in an IPv4 based network environment, handover of a mobile terminal between different networks is achieved through switching of an active tunnel and a standby tunnel, and thus handover between different networks is facilitated and data loss is prevented to secure continuity of service provided to the mobile terminal even when the mobile terminal hands over to a heterogeneous network.

Abstract: In order to select a conference processing device to host a video conference between conference participation devices, a video conference system selects conference processing devices that are positioned most adjacent to each of conference participation devices that participate in the video conference as candidates for a conference processing device. The video conference system forms network topology based on candidate conference processing devices and conference participation devices, and aligns candidate conference processing devices based on preset alignment reference information. The video conference system selects one of the aligned candidate conference processing devices as an optimal conference processing device to host the video conference.

Abstract: The present invention relates to tunneling an IPv6 packet through an IPIv4 network. In using a tunneling method upon transmitting an IPv6 packet in an IP network, when destination nodes desired to be communicated are located within the same IPv6 prefix network, IPv6 prefix information is added for the management of a tunnel entry. Hence, tunneling information on terminals located within the same IPv6 prefix network can be managed as one tunnel entry. Accordingly, the time consumed when retrieving a tunnel entry can be reduced.

Abstract: Provided is a method of establishing a user centric virtual network. The method includes: performing a first tunneling operation between a first tunnel end and an address translation device, which are connected to a first private network, and a tunnel relay device; performing a second tunneling operation between a second tunnel end and an address translation device, which are connected to a second private network, and the tunnel relay device; and performing a third tunneling operation between the tunnel relay device and an end client, wherein a virtual IP is allocated to each of the first and second tunnel ends, the address translation devices, the end client, and the tunnel relay device; and each of the first to third tunneling operations connects routing information on the virtual IP to a corresponding tunnel.

Abstract: Provided is a method for configuring a control tunnel and a direct tunnel in an IPv4 network-based IPv6 service providing system. To provide IPv6 service, when a random request terminal receives a tunnel response message from a control server by using service information downloaded from a portal server at the time of initialization, the request terminal configures a control tunnel with the control server, and is registered to the control server. The request terminal transmits and receives a direct tunnel request message and a direct tunnel response message with a counterpart terminal by using its terminal information learned during the control tunnel configuration, i.e., network position information and status information, thereby configuring a direct tunnel. Thus, IPv6 communication is made through IPv4 based IPv6 tunneling, so that IPv6 application services that are not yet widely used can easily come into wide use.

Abstract: Disclosed are a system for managing virtual private networks (VPNs) includes: terminals configured to transmit user data; a manager configured to transmit information for concealing networks and managing the VPNs; border gateways configured to decrypt the user data and perform a network address translation (NAT) procedure and a filtering procedure on the decrypted user data based on the information; and servers configured to receive the user data subjected to the NAT procedure and the filtering procedure, wherein the filtering procedure is a procedure discarding the user data to be transferred to the servers that are not allowed so as to allow the terminals to access only the allowed servers, the NAT procedure is a procedure changing an Internet protocol (IP) address used in a first network to an IP address used in a second network, and the first network and the second network are different networks.

Abstract: In a plurality of virtual tunnel routers including a first virtual tunnel router and a second virtual tunnel router, the first virtual tunnel router and the second virtual tunnel router request virtual network prefix information from a tunnel mapping controller. When the tunnel mapping controller generates virtual network prefix information of the first virtual tunnel router and the second virtual tunnel router, respectively, and transmits the same along with information of a list of adjacent virtual tunnel routers, the first virtual tunnel router and the second virtual tunnel router create a tunnel. With the tunnel established, the virtual network prefix information received by the first virtual tunnel router and second virtual tunnel router, respectively, is linked so that direct communication can be performed between the first virtual tunnel router and the second virtual tunnel router.

Abstract: The invention relates to a method and an apparatus for controlling seamless handover between heterogeneous networks based on IPv6 over IPv4 tunneling. When IPv6 service is provided using tunneling in an IPv4 based network environment, handover of a mobile terminal between different networks is achieved through switching of an active tunnel and a standby tunnel, and thus handover between different networks is facilitated and data loss is prevented to secure continuity of service provided to the mobile terminal even when the mobile terminal hands over to a heterogeneous network.

Abstract: Enclosed is a method of supporting mobility using a security tunnel. For the movement of a terminal in a local network and the movement of a terminal to an external network, an active tunnel and a standby tunnel are set to provide mobility to the terminal. When the local network moves, mobility for the local network is provided. The stability of a network is guaranteed using security connection.

Abstract: Technology for forming a virtual private network (VPN) is provided. A VPN gateway that supports mobility with a connection node having a virtual home address (HoA) and a care of address (CoA) includes a mobility support unit, a data security unit, and a virtual address converter. When a packet is transferred from the connection node, the mobility support unit sustains a binding relationship between a home address (HoA) of the connection node and the changed CoA, and processes a mobility tunnel for the packet, thereby generating a first conversion packet. The data security unit performs a security test of the first conversion packet. The virtual address converter converts the HoA of the connection node, which is a source address of the first conversion packet in which the security test is complete, to a private network internal address that can be used in the VPN, thereby generating a second conversion packet.

Abstract: In order for a peer node to perform direct communication with a correspondent peer node in an Internet protocol network, the peer node receives a virtual address of the correspondent peer node from a server, and then when the peer node can directly set a tunnel with the correspondent peer node, the peer node sets a tunnel with the correspondent peer node, and when the peer node cannot directly set a tunnel with the correspondent peer node, the peer node sets a tunnel with a tunnel repeater. Thereafter, the peer node connects a virtual address of the correspondent peer node as route information to the tunnel. Thereby, a packet using a virtual address of the correspondent peer node as a destination is transmitted to the correspondent peer node through a predetermined tunnel.

Abstract: The present invention relates to tunneling an IPv6 packet through an IPv4 network. In using a tunneling method upon transmitting an IPv6 packet in an IP network, when destination nodes desired to be communicated are located within the same IPv6 prefix network, IPv6 prefix information is added for the management of a tunnel entry. Hence, tunneling information on terminals located within the same IPv6 prefix network can be managed as one tunnel entry. Accordingly, the time consumed when retrieving a tunnel entry can be reduced.

Abstract: A method for providing a service of downloading stereoscopic image data including first image data and second image data in a digital broadcasting system includes: generating information regarding a file name of each of the first image data and the second image data; and transmitting the first image data, the information regarding the file name of the first image data, the second image data, and the information regarding the file name of the second image data. The file name of the second image data includes a prefix indicating the second image data of the stereoscopic image data.