Relay communication system and relay servers

A relay communication system comprising:

• a first network;
• a second network;
• a first relay server connected to the first network;
• a second relay server connected to the second network, and configured to communicate with the first relay server via a third network;
• a client terminal connected to the first relay server via the first network;
• and
• a client terminal connected to the second relay server via the second network;
• wherein
• each of the first relay server, the second relay server, the client terminal connected to the first relay server, and the client terminal connected to the second relay server includes:
• a relay group information storage unit configured to store relay group information that indicates the first relay server, the second relay server, and the client terminal connected to the first relay server, and the client terminal connected to the second relay server define a relay group;
• a relay server information storage unit configured to store relay server information that includes activation information of the first relay server, activation information of the second relay server, activation/registration information of the client terminal connected to the first relay server, and activation/registration information of the client terminal connected to the second relay server;
• an information sharing unit configured to allow the first relay server, the second relay server, the client terminal connected to the first relay server, and the client terminal connected to the second relay server, to share the relay group information and the relay server information;
• a VLAN group information control unit programmed and configured to allow VLAN client terminals defining a VLAN group in the relay group to share VLAN group information, at least two client terminals among the client terminal connected to the first relay server and the client terminal connected to the second relay server being the VLAN client terminals, and the VLAN group information including hub information including identification information of the first relay server and identification information of the second relay server to which the VLAN client terminal is connected, session information that indicates a connecting-side and a connected-side of a session established between the first relay server and the second relay server, and identification information that identifies the VLAN client terminal,
• each of the first relay server and the second relay server further includes:
• an activation command control unit programmed and configured to transmit a response signal including address information of a VLAN device as a VLAN client terminal that is arranged to be activated in a case of receiving an activation instruction of the VLAN group;
• and
• a VLAN session control unit programmed and configured to establish a hub session as a VLAN session between the first relay server and the second relay server based on the session information, and establish a device session as a VLAN session between the VLAN devices connected to the first relay server or the second relay server;
• each of the client terminal connected to the first relay server and the client terminal connected to the second relay server further includes a virtual address control unit programmed and configured to create virtual address information that includes virtual addresses given to the VLAN devices based on the response signal, and transmit the virtual address information to the VLAN device;
• if the client terminal connected to the first relay server or the client terminal connected to the second relay server is a VLAN device, the client terminal is configured to set the given virtual address in a VLAN interface of the client terminal, and communicate with other VLAN device using the virtual address information and the VLAN session.

A relay server configured to serve as a second relay server connected to a second network, and communicate with a first relay server connected to a first network, the relay server comprising:

• a relay group information storage unit configured to store relay group information indicating that the first relay server, the second relay server, a client terminal connected to the first relay server, and a client terminal connected to the second relay server define a relay group;
• a relay server information storage unit configured to store relay server information including activation information of the first relay server, activation information of the second relay server, activation/registration information of the client terminal connected to the first relay server, and activation/registration information of the client terminal connected to the second relay server;
• an information sharing unit configured to allow the first relay server, the second relay server, the client terminal connected to the first relay server, and the client terminal connected to the second relay server, to share the relay group information and the relay server information;
• a VLAN group information control unit programmed and configured to share VLAN group information among VLAN client terminals defining a VLAN group in the relay group, at least two client terminals among the client terminals connected to the first relay server and the second relay server being the VLAN client terminals, and the VLAN group information including hub information including identification information of the first relay server and the second relay server to which the VLAN client terminal is connected, session information that indicates a connecting-side and a connected-side in a session established between the first relay server and the second relay server, and identification information that identifies the VLAN client terminal;
• an activation command control unit programmed and configured to transmit a response signal including address information of a VLAN device that is arranged to be activated as a VLAN client terminal in a case of receiving an activation instruction of the VLAN group;
• a virtual address control unit programmed and configured to transmit the virtual address information to the VLAN device, when receiving virtual address information that includes virtual addresses given to the VLAN devices and is created based on the response signal;
• a VLAN session control unit programmed and configured to establish a hub session as a VLAN session with the first relay server based on the session information, and establish a device session as a VLAN session with the VLAN device connected to the relay server;
• and
• a relay server communication control unit programmed and configured to control communication among the VLAN devices using the virtual address information and the VLAN session.