Abstract: A center terminal includes a target terminal list storing unit that registers a target terminal and an operator list storing that registers an operator ID and a password. Each of the maintenance terminal and the target terminal includes a center terminal information storing unit that registers a center terminal. The center terminal makes a connection job that associates a predetermined target terminal with the operator ID and registers the connection job to the center terminal. One of maintenance terminals receives the specific operator ID and the password from a connected client terminal and sends the center terminal an indication whether or not the maintenance terminal can log in to the center terminal, and, if the logging-in is granted, the maintenance terminal is configured to receive the connection job assigned to the operator ID from the center terminal and notify the operator.

Abstract: A relay server stores a routing apparatus belonging to a VPN group to which the relay server itself belongs, a second routing object address that is an address of the routing apparatus, and the like. The relay server stores a relationship of assignment of a virtual address to the second routing object address. The virtual address is an address that does not overlap with addresses of any other apparatuses. The relay server, upon receipt of a packet from a routing session, converts a source of the packet from an actual address into the virtual address and forwards the packet to a routing object device of the relay server itself. The relay server, upon receipt of a packet from the routing object device of the relay server itself, converts a destination of the packet from the virtual address into an actual address and forwards the packet to the routing session.

Abstract: A virtual network is dynamically created when a relay communication system is constructed including a plurality of relay servers that communicate with each other. In the relay communication system, VLAN client terminals which define a VLAN group share VLAN group information. In addition, a VLAN session is established between the VLAN devices as activatable VLAN client terminals among the VLAN client terminals based on the VLAN group information, and the VLAN devices are allowed to share virtual address information created when the VLAN group is activated. Furthermore, if the VLAN group has already been activated when instructed to activate the VLAN group, a join-in-progress signal to the VLAN group is transmitted to a join-in-progress VLAN client terminal as a transmission source of the activation instruction, and a VLAN session is established that is related to the join-in-progress VLAN client terminal and has not been established yet.

Abstract: Communication is established between communication terminals arranged in different LANS while realizing dynamic response to reduction in server load, movement of communication terminal, and the like. A relay server is arranged in a LAN and can communicate with an SIP server arranged in a WAN. For instance, a first relay server exchanges account information of the communication terminals in the respective LAN with a second relay server. If exchanged account information is changed in one relay server, the account information after the change is notified to the other relay server. One relay server determines the other relay server based on the exchanged account information and relays communication data between the communication terminals through the other relay server.

Abstract: A relay server performs control to establish a routing session between the relay server and another routing relay server, control to establish a sub routing session between the relay server and a sub routing apparatus, and a packet forward control to forward a received packet via the routing session or the sub routing session. The packet forward control is such a control that, when a destination of a packet is associated with the sub routing apparatus of the relay server in a content stored in a sub address filter information storage unit, the packet is forwarded to the sub routing apparatus, while otherwise the packet is forwarded to the destination.

Abstract: A relay server presents, to an operator having made a login request, a list of connecting-target apparatuses to which the operator is able to connect. When, for example, a client terminal is selected from the list, the relay server stores, as address filter information of the relay server, an address of a communication apparatus operated by the operator, and transmits the address filter information to the client terminal. The relay server stores address filter information received from the client terminal. Then, a routing session for a VPN is established between the relay server and the client terminal, and routing of a packet is performed based on the address filter information.

Abstract: A communication device includes a communication unit configured to communicate with a LAN, and IO ports connectable to a manufacturing apparatus, and a controller. The IO ports are configured and/or programmed to exchange ON/OFF signals including multiple bits with the manufacturing apparatus. The controller is configured and/or programmed to receive communication requests from communication destinations via the LAN, store network addresses of communication destinations and IO port designations, change a value of the ON/OFF signals of designated IO ports in accordance with requests from communication destinations, and transmit the ON/OFF signals of designated IO ports to communication destinations via the communication unit and the LAN in accordance with requests from the communication destinations.

Abstract: A first relay server transmits, to an access management apparatus that manages an access right to a second relay server, an access request with respect to the second relay server. The access management apparatus confirms that the access right to the second relay server is set in the first relay server, and then requests the second relay server to permit an access by the first relay server. In a case where the second relay server permits the access from the first relay server, the access management apparatus notifies the first relay server of such access permission. Based on the notice from the access management apparatus, the first relay server establishes a routing session with the second relay server. By using the routing session, the first relay server starts the communication with a general server that serves as a maintenance target.

Abstract: A virtual network is dynamically created when constructing a relay communication system including a plurality of relay servers that are arranged to communicate with each other. In the relay communication system, the VLAN client terminals defining a VLAN group are allowed to share VLAN group information. In addition, a VLAN session between VLAN devices as activatable VLAN client terminals is established based on the VLAN group information, and the VLAN devices are allowed to share virtual address information created when the VLAN group is activated. If the VLAN device defining the activated VLAN group is suspended, suspension of the VLAN device is notified, and a VLAN device about which the suspension has been notified is deleted from the virtual address information. The VLAN session related to the VLAN device about which the suspension has been notified is closed.

Abstract: A relay server and a relay communication system can easily synchronize resource information with a resource when terminals share the resource. When an instruction to synchronize shared resource information is given, the relay server transmits the synchronization instruction to each resource sharing terminal based on the shared resource information. Having received the synchronization instruction, when the shared resource information includes the resource that is owned by the terminal, the resource sharing terminal compares the resource information and the resource. If the resource information and the resource do not match, the resource sharing terminal updates the resource information to the latest information, and transmits, to the relay server, an instruction to update the shared resource information including the resource information. Thus, the resource information of an entire network can be synchronized by one synchronization instruction.

Abstract: A relay server stores a first routing target address, and stores a second routing target address in association with a virtual address assigned to the second routing target address. The relay server exchanges address filter information with a relay server belonging to a selected VPN group, and establishes a routing session with the relay server. The relay server determines whether or not there is an overlap between the routing target addresses. Upon determination that there is an overlap, the relay server assigns a virtual address to the second routing target address. The relay server uses the virtual address to perform communication between the relay server itself and a first routing target device.

Abstract: In a relay communication system, if a request to perform a first remote operation on a first client terminal selected based on relay server information is received from a third client terminal, then a first relay server relays an operation event and image data, which are operation data of the first remote operation performed based on the first remote operation request, via an operation-performing session established between the second relay server and the first client terminal. If a monitoring request to monitor the first remote operation is received from a second client terminal, then the first relay server establishes a monitoring session with the second client terminal and transmits the operation data of the first remote operation via the monitoring session. As a result, a terminal other than the terminal that performs the remote operation or the terminal that undergoes the remote operation is capable of acquiring the content of the remote operation.

Abstract: In a relay communication system, a method and apparatus prevent crossover among call controls in sections and crossover among communication routes in each of the sections. Relay servers relay communication between client terminals. A relay server creates information, and allows a whole of a relay communication system to share the information, which includes: relay group information indicating that the relay servers constitute a relay group; and relay server information indicating a client terminal capable of communicating with the relay server. The relay servers and the client terminals collate identification information of call control, transmitted when the call control is executed for a destination for communication in each section, and identification information of call control, received from the destination for communication in each section when a communication route is established, with each other, and allows the call controls and the communication routes to correspond to each other.

Abstract: A relay communication system includes a first client terminal which creates routing group information including network addresses of first and second LANs, and identification information of the first client terminal and a second client terminal which execute routing processing, and which shares the routing group information with the second client terminal. Based on the routing group information, a routing session is established between the first and second client terminals. A communication terminal connected to the first LAN sends out a communication packet in which an IP address of a communication terminal connected to the second LAN is designated. The communication packet is encapsulated by the first client terminal, and is routed by using the routing session.

Abstract: A relay server stores a routing apparatus belonging to a VPN group to which the relay server itself belongs, a second routing object address that is an address of the routing apparatus, and the like. The relay server stores a relationship of assignment of a virtual address to the second routing object address. The virtual address is an address that does not overlap with addresses of any other apparatuses. The relay server, upon receipt of a packet from a routing session, converts a source of the packet from an actual address into the virtual address and forwards the packet to a routing object device of the relay server itself. The relay server, upon receipt of a packet from the routing object device of the relay server itself, converts a destination of the packet from the virtual address into an actual address and forwards the packet to the routing session.

Abstract: A communication system achieves excellent flexibility and expandability and includes communication terminals that communicate with each other through a WAN. A first relay server and a second relay server share relay group information and relay server information. In the relay group information, a network address of a first LAN that performs routing control via the first relay server and a network address of a second LAN that performs routing control via the second relay server are registered. The first and second relay servers establish a routing session via a WAN. When a communication terminal connected to the first LAN sends out a communication packet in which an IP address of a communication terminal connected to the second LAN is designated, the communication packet is routed through the routing session between the first and second relay servers while being encapsulated.

Abstract: A first relay server stores a first routing target address and a second routing target address. The first relay server stores a first routing target address and a virtual address allocated to the first routing target address while being correlated with each other. The first relay server allocates the virtual address to the first routing target address. The first relay server sets whether communication is conducted using the virtual address or the first routing target address with respect to each second relay server. The first relay server transmits the virtual address allocated to the first routing target address to the second relay server, and receives the second routing target address from the second relay server, so as to establish a routing session with the second relay server. The first relay server performs routing control based on the exchanged routing target address.

Abstract: A relay server presents, to an operator having made a login request, a list of connecting-target apparatuses to which the operator is able to connect. When, for example, a client terminal is selected from the list, the relay server stores, as address filter information of the relay server, an address of a communication apparatus operated by the operator, and transmits the address filter information to the client terminal. The relay server stores address filter information received from the client terminal. Then, a routing session for a VPN is established between the relay server and the client terminal, and routing of a packet is performed based on the address filter information.

Abstract: A center terminal includes a target terminal list storing unit that registers a target terminal and an operator list storing that registers an operator ID and. Each of the maintenance terminal and the target terminal includes a center terminal information storing unit that registers a center terminal. The center terminal makes a connection job that associates a predetermined target terminal with the operator ID and registers the connection job to the center terminal. One of maintenance terminals receives the specific operator ID and the password from a connected client terminal and sends the center terminal an indication whether or not the maintenance terminal can log in to the center terminal, and, if the logging-in is granted, the maintenance terminal is configured to receive the connection job assigned to the operator ID from the center terminal and notify the operator.

Abstract: A relay communication device includes a first communication unit, a second communication unit, and a communication buffer. When receiving data in the first communication unit, each relay communication device temporarily accumulates the data in the communication buffer. The relay communication device functioning as a master asks the relay communication device functioning as a slave if there is data in the communication buffer. The master grants transmission permission to the slave that has returned a reply indicating that there is data. The slave that has received the transmission permission transmits the data to a slave that is a destination of the data. The master makes an inquiry into a next slave in the case where the slave which has been granted the transmission permission completes the transmission of the data from the second communication unit. The allowed amount of data transmitted by each relay communication device at one time is limited.