News Column

Researchers Submit Patent Application, "Relay Server and Relay Communication System", for Approval

July 8, 2014



By a News Reporter-Staff News Editor at Information Technology Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventor Tanimoto, Yoshifumi (Kyoto-shi, JP), filed on March 6, 2012, was made available online on June 26, 2014.

The patent's assignee is Murata Machinery, Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates mainly to a relay server that enables communication to be performed between apparatuses connected to different LANs (Local Area Networks).

"Conventionally, a communication technology called a virtual private network (Virtual Private Network, VPN) has been known, which allows communication to be performed between LANs installed in physically distant places. Japanese Patent Application Laid-Open No. 2010-268312 shows an example in which a relay server, a communication terminal, and the like, are connected to each of a plurality of LANs installed in physically distant places. With use of the VPN, a communication terminal is able to transmit a packet to a communication terminal connected to another LAN. More specifically, a packet transmitted by a communication terminal is firstly sent to a relay server belonging to a LAN that the communication terminal belongs to. This relay server transmits (forwards) the packet, via Internet, to a relay server belonging to a LAN that a destination communication terminal belongs to. The relay server receives the packet, and transmits (forwards) the packet to the destination communication terminal.

"Use of the VPN enables another LAN located in a distant place to be used as if it is a directly-connected network.

"In a LAN, not only the above-described VPN communication but also communication using no VPN is often performed. In such a case, a packet is firstly transmitted not to a relay server but to an apparatus (for example, a router) that functions as a default gateway. The apparatus that functions as a default gateway forwards the received packet in accordance with a destination of the packet.

"Thus, in a case of communication with use of the VPN, it is necessary that a relay server is designated as a primary destination of a packet, and in a case of communication without use of the VPN, it is necessary that an apparatus that functions as a default gateway is designated as a primary destination of a packet. For this purpose, it is necessary to preset a gateway table in which a final destination of a packet and a primary destination of the packet are associated with each other.

"However, in many cases, it is not until a VPN is built that an address of a communication partner through the VPN is revealed. Therefore, the gateway table needs to be updated each time a VPN is built, which results in a complicated process."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "In view of the circumstances described above, preferred embodiments of the present invention provide a relay server that eliminates a process to update a gateway table which otherwise should be performed each time a VPN is built.

"In a first preferred embodiment of the present invention, a relay server having the following configuration is provided. The relay server includes an address filter information storage unit, a virtual address registration information storage unit, a virtual address assignment information storage unit, and a control unit. The address filter information storage unit stores a first routing object address and a second routing object address, the first routing object address being an address of a first routing object device that is located in a first LAN and to which the relay server is able to forward a packet, the second routing object address being an address of a second routing object device to which a second relay server located in a second LAN is able to forward a packet. The virtual address registration information storage unit stores an address that is registered as a virtual address and that does not overlap in the first LAN. The virtual address assignment information storage unit stores the relationship of assignment of the virtual address to the second routing object address. The control unit transmits the first routing object address to the second relay server and receives the second routing object address from the second relay server, and establishes a routing session between the relay server and the second relay server. The control unit assigns the virtual address to the second routing object address and stores the relationship of the assignment into the virtual address assignment information storage unit. Upon receipt of a packet whose destination is the first routing object address from the routing session, the control unit refers to the virtual address assignment information storage unit and converts a source address of the packet into the virtual address assigned to the second routing object address, and forwards the packet to the first routing object device that is the destination. Upon receipt of a packet whose destination is the virtual address from the first routing object device, the control unit refers to the virtual address assignment information storage unit and converts a destination address of the packet into the second routing object address having the virtual address assigned thereto, and forwards the packet to the routing session.

"Accordingly, by associating in advance the virtual address with the address of the relay server in a gateway table in which a destination address is associated with a gateway address, setting of the gateway table is eliminated, which conventionally should be performed each time a VPN is built.

"In the relay server, it is preferable that whether or not to de-assign the virtual address assigned to the second routing object address at a time when the routing session is disconnected is settable.

"Accordingly, in a case of building a VPN and performing communication, for example, setting is performed so as to de-assign the virtual address at a time when the routing session is disconnected, for a partner with which a VPN is less frequently built. This prevents occupation of a virtual address, and prevents a decrease in the number of assignable virtual addresses. On the other hand, for a partner with which a VPN is frequently built, setting is performed so as not to de-assign the virtual address at a time when the routing session is disconnected. This eliminates the need to assign a virtual address each time a VPN is built, which results in an efficient reduction in the throughput. Moreover, since the virtual address is not de-assigned, the communication can be performed always using the same virtual address. This simplifies management of the communication, and the like.

"In the relay server, it is preferable that whether to assign the virtual address to the second routing object address and perform communication by using the virtual address or to perform communication by using the second routing object address is settable.

"This achieves flexible communication based on network environments, the status of use of the address, and the like.

"In the relay server, it is preferable that whether to perform communication by using the virtual address or to perform communication by using the second routing object address is settable for each relay server.

"Accordingly, in a case of building a VPN and performing communication, for example, an actual address is used only for a partner with which a VPN is frequently built. This enables communication to be performed by using the same address even when the routing session is disconnected, while still preventing occupation of the virtual address.

"In a second preferred embodiment of the present invention, a relay communication system having the following configuration is provided. The relay communication system includes a plurality of relay servers including a first relay server and a second relay server, and client terminals. The client terminals belong to the relay servers. The first relay server located in a first LAN includes a VPN group information storage unit, an address filter information storage unit, a virtual address registration information storage unit, a virtual address assignment information storage unit, and a control unit. The VPN group information storage unit stores routing apparatuses belonging to the same VPN group, the VPN group being a group made up of the routing apparatuses, the routing apparatuses being apparatuses that function as routing points from the relay servers and the client terminals, the VPN group allowing communication between the routing apparatuses via a virtual private network. The address filter information storage unit stores a first routing object address and a second routing object address, the first routing object address being an address of a first routing object device that is located in the first LAN and to which the first relay server is able to forward a packet, the second routing object address being an address of a second routing object device to which the second relay server located in a second LAN is able to forward a packet. The virtual address registration information storage unit stores an address that is registered as a virtual address and that does not overlap in the first LAN. The virtual address assignment information storage unit stores the relationship of assignment of the virtual address to the second routing object address. The control unit transmits the first routing object address to the second relay server and receives the second routing object address from the second relay server, and establishes a routing session between the first relay server and the second relay server. The control unit assigns the virtual address to the second routing object address and stores the relationship of the assignment into the virtual address assignment information storage unit. Upon receipt of a packet whose destination is the first routing object address from the routing session, the control unit refers to the virtual address assignment information storage unit and converts a source address of the packet into the virtual address assigned to the second routing object address, and forwards the packet to the first routing object device that is the destination. Upon receipt of a packet whose destination is the virtual address from the first routing object device, the control unit refers to the virtual address assignment information storage unit and converts a destination address of the packet into the second routing object address having the virtual address assigned thereto, and forwards the packet to the routing session.

"Accordingly, by associating in advance the virtual address with the address of the relay server in the above-mentioned gateway table, setting of the gateway table is eliminated, which conventionally should be performed each time a VPN is built.

"The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 is a diagram for explaining an overall configuration of a relay communication system according to a preferred embodiment of the present invention.

"FIG. 2 is a function block diagram of a relay server.

"FIG. 3 is a diagram showing a content of relay group information.

"FIG. 4 is a diagram showing a content of relay server information.

"FIGS. 5A-5C are diagrams showing a content of client terminal information.

"FIG. 6 is a diagram showing a content of VPN group information.

"FIGS. 7A-7C are diagrams showing a content of address filter information that is registered in advance in each relay server.

"FIG. 8 is a diagram showing a content stored in an address filter information storage unit after a VPN is built.

"FIG. 9 is a diagram showing a content of virtual address registration information.

"FIG. 10 is a diagram showing a content of virtual address assignment information.

"FIG. 11 is a diagram showing a content of a gateway table that is set for object terminals.

"FIG. 12 is a flowchart showing a setting process performed in the relay server in advance.

"FIG. 13 is a flowchart showing a process for making a VPN group.

"FIG. 14 is a flowchart showing a VPN building process.

"FIG. 15 is a flowchart showing the VPN building process.

"FIG. 16 is a flowchart showing a routing control using a virtual address.

"FIGS. 17A and 17B are diagrams for explaining the routing control using the virtual address.

"FIG. 18 is a diagram showing a content of virtual address management information."

For additional information on this patent application, see: Tanimoto, Yoshifumi. Relay Server and Relay Communication System. Filed March 6, 2012 and posted June 26, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4425&p=89&f=G&l=50&d=PG01&S1=20140619.PD.&OS=PD/20140619&RS=PD/20140619

Keywords for this news article include: Murata Machinery Ltd, Information Technology, Information and Data Storage.

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Source: Information Technology Newsweekly


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