JP2012109872A - Relay server and relay communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relay server that can start a virtual network, flexibly coping with the situation even if the state of a network has changed.SOLUTION: A relay server comprises a VPN group information storage unit, an address filter information storage unit, and a communication control unit. The VPN group information storage unit stores identification information of routing devices constituting a VPN group and routing session information indicating the routing devices connected with each other. The address filter information storage unit stores address filter information indicating a communication partner which a routing device can specify as a transmission destination of a packet by associating the address filter information with the identification information of the routing device. The communication control unit updates memory content of the address filter information storage unit based on the address filter information received from a routing device when starting a VPN for a VPN group, and controls establishment of a routing session based on the routing session information.

Description

  The present invention mainly relates to a relay server that enables communication between terminals connected to different LANs (Local Area Networks).

  Conventionally, a communication technique called a virtual private network (VPN) is known (see, for example, Patent Document 1). This VPN is used, for example, for applications in which terminals connected to LANs of a plurality of branch offices (bases) provided for each region communicate via the Internet. If the VPN is used, another remote LAN can be used as if it were a directly connected network.

JP 2002-217938 A

  However, this type of system tends to be rigid, and it is not easy to construct a system that is extensible and flexible. For example, a communication system such as that disclosed in Patent Document 1 cannot construct a virtual network with only a part of selected devices among the devices constituting the system. Further, even if the virtual network can be normally operated at the beginning, for example, when the configuration of the network device is changed or the setting is changed, the virtual network may not be properly constructed thereafter.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a relay server that can flexibly cope with a change in the network status and start a virtual network. is there.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to a first aspect of the present invention, a relay server having the following configuration is provided. That is, the relay server includes a relay group information storage unit, a relay server information storage unit, a VPN group information storage unit, an address filter information storage unit, and a communication control unit. The relay group information storage unit stores information on relay groups including other relay servers that can be connected to each other. The relay server information storage unit stores relay server information including start information of the relay server belonging to the relay group and start information and registration information of a client terminal connected to the relay server belonging to the relay group. To do. The VPN group information storage unit is configured by a routing device that is a communication device set as a routing point among communication devices that constitute a relay communication system based on the relay group information and the relay server information. With respect to a VPN group that performs communication via a virtual private network, the identification information of the routing device that constitutes the VPN group and the connection information that indicates the routing device connected to each other are stored. The address filter information storage unit stores address filter information indicating a partner that can be designated by the routing device as a packet transmission destination in association with identification information of the routing device. The communication control unit controls the information stored in the VPN group information storage unit to be shared between the routing devices, and when starting a virtual private network in the VPN group, sends the address filter to another routing device. Transmitting the information, receiving the address filter information from the routing device, updating the storage contents of the address filter information storage unit based on the address filter information, and storing the connection stored in the VPN group information storage unit Based on the information, control for establishing a routing session for routing the packet, and after establishing the routing session, refer to the other party that the routing device can designate as a transmission destination based on the address filter information. Base And a control for routing Te, is carried out.

  As a result, the relay server can construct a VPN with a routing device selected from other communication devices (other relay servers and client terminals) constituting the relay communication system. Share and so on. In addition, since the relay server acquires address filter information from other routing devices when starting VPN in the VPN group, the VPN can be used even when there is a routing device whose address filter information has been changed. Can be built.

  In the relay server, the VPN group information storage unit includes, as the connection information, identification information of the routing device on the side that first performs communication control for establishing a routing session, and information on the side that receives the communication control. It is preferable to store identification information of the routing device.

  Thus, when starting a VPN in a VPN group, in order to establish a routing session between two mutually connected routing devices, it is possible to predefine which routing device performs communication control first. it can. Therefore, communication control collision can be prevented.

  The relay server preferably has the following configuration. That is, when the destination of the received packet is specified in the address filter information associated with its own identification information, the relay server transmits the packet to the destination. When the destination of the received packet is specified in the address filter information associated with the identification information of the routing device other than itself, the relay server establishes the routing established between itself and the routing device. A packet is transmitted to the routing device via the session. The relay server does not transmit the packet when the destination of the received packet is not specified in the address filter information associated with the identification information of the routing device.

  Thereby, the relay server can perform routing appropriately based on the address filter information.

  The relay server preferably has the following configuration. That is, the first communication device, which is the routing device connected to the wide area communication network via the second relay server, is connected to the wide area communication network via itself from the first state constituting the VPN group. In the case where the second communication device switches to the second state constituting the VPN group, the communication control unit includes the first communication device in the first state and the second communication in the second state. When the device has the same identification information, when starting the virtual private network in the second state, the connection partner of the first communication device in the first state and the second communication Control is performed to establish a routing session between itself and the device.

  Thereby, it is possible to construct a VPN that can flexibly cope with the case where the configuration of the VPN group changes beyond the relay server. Further, it is possible to construct the VPN in the second state by effectively using the VPN group information in the first state.

  In the relay server, it is preferable that the address filter information storage unit can store a name of a partner that can be designated by the routing device as a packet transmission destination.

  Thereby, for example, when referring to the address filter information, the user can know not only the IP address of the partner to which the packet can be transmitted but also the name at the same time.

  According to the 2nd viewpoint of this invention, the relay communication system of the following structures is provided. That is, this relay communication system includes a plurality of relay servers and client terminals. The client terminals can be connected to each other via the relay server. The relay server includes a relay group information storage unit, a relay server information storage unit, a VPN group information storage unit, an address filter information storage unit, and a communication control unit. The relay group information storage unit stores information on relay groups including other relay servers that are mutually connectable with the relay server. The relay server information storage unit stores relay server information including start information of the relay server belonging to the relay group, start information and registration information of the client terminal. The VPN group information storage unit includes a routing device that is set as a routing point among the relay server and the client terminal, and relates to a VPN group that performs communication through a virtual private network via the routing device. The identification information of the routing device to be configured and the connection information indicating the routing device connected to each other are stored. The address filter information storage unit stores address filter information indicating a partner that can be designated by the routing device as a packet transmission destination in association with identification information of the routing device. The communication control unit controls the information stored in the VPN group information storage unit to be shared between the routing devices, and when starting a virtual private network in the VPN group, sends the address filter to another routing device. Transmits information and receives the address filter information from the routing device, updates the content stored in the address filter information storage unit, and routes packets based on the connection information stored in the VPN group information A control for establishing a routing session, and a control for performing routing based on the contents by referring to a partner that can be designated as a transmission destination by the routing device based on the address filter information after the routing session is established. Do.

  As a result, the VPN can be constructed using the routing device selected from the relay server and the client terminal, so that the file can be shared only with the necessary device. In addition, since this relay communication system exchanges address filter information between routing devices when VPN is started in a VPN group, it is possible to cope with a case where there is a routing device whose address filter information has been changed. VPN can be constructed.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the whole structure of the relay communication system which concerns on one Embodiment of this invention. The functional block diagram of a relay server. The figure which shows the content of relay group information. The figure which shows the content of relay server information. The figure which shows the content of client terminal information. The figure which shows the content of VPN group information. The figure which shows the memory content of an address filter information storage part. The flowchart which shows the process which produces a VPN group. The flowchart which shows the first half part of the process which starts VPN. The flowchart which shows the second half part of the process which starts VPN. The sequence diagram which shows the communication process which creates a VPN group, and the communication process which updates address filter information. The sequence diagram which shows the communication process which establishes a routing session, and performs the transmission of a packet. The sequence diagram which shows the communication process which complete | finishes a VPN group. The sequence diagram which shows a communication process when remote login is performed. The sequence diagram which shows a communication process when transmitting a packet via the client terminal in remote login. The figure which shows the memory content of the address filter information storage part after being updated with the address filter information produced at the time of remote login.

  Next, embodiments of the present invention will be described with reference to the drawings. First, an overview of the relay communication system 100 of the present embodiment will be described with reference to FIG. FIG. 1 is an explanatory diagram showing the overall configuration of a relay communication system 100 according to an embodiment of the present invention.

  As shown in FIG. 1, the relay communication system 100 includes a plurality of LANs 10, 20, 30, and 40 connected to a wide area network (WAN) 80. Each of the LANs 10, 20, 30, 40 is a relatively small network constructed in a limited place, and each is constructed in a physically separated place. In the present embodiment, the Internet is used as the WAN 80.

  Each LAN will be specifically described below. As shown in FIG. 1, a relay server 1, a client terminal 11, and a processing device 12 are connected to the LAN 10. A relay server 2, a client terminal 21, a processing device 22, and a processing device 23 are connected to the LAN 20. A relay server 3, a client terminal 31, a processing device 32, and a processing device 33 are connected to the LAN 30. A relay server 4, a client terminal 41, and a processing device 42 are connected to the LAN 40.

  Since each relay server 1, 2, 3, 4 is connected not only to the LAN 10, 20, 30, 40 but also to the WAN 80, not only can it communicate with a client terminal connected to the same LAN, Communication is possible with a relay server arranged in another LAN. Therefore, a private IP address is given to the relay servers 1, 2, 3, and 4 in addition to the global IP address.

  The client terminals 11, 21, 31, 41 are constituted by personal computers, for example, and can communicate with each other via the relay servers 1, 2, 3, 4. The processing devices 12, 22, 23, 32, 33, and 42 are constituted by personal computers, for example, and can transmit packets to the client terminals 11, 21, 31, and 41 via the LANs 10, 20, 30, and 40. .

  Next, the relay servers 1, 2, 3, and 4 will be described. Since these four relay servers have substantially the same configuration except for some stored data, the relay server 1 will be described as a representative. First, the configuration of the relay server 1 will be described with reference to FIG. FIG. 2 is a functional block diagram of the relay servers 1, 2, 3, and 4.

  As illustrated in FIG. 2, the relay server 1 includes a storage unit 50, a control unit 60, and an interface unit 70.

  The interface unit 70 can communicate with a terminal in the LAN 10 using a private IP address. In addition, the interface unit 70 can perform communication via the WAN 80 using a global IP address.

  The control unit 60 is a CPU having control and calculation functions, for example, and can execute various processes by a program read from the storage unit 50. The control unit 60 can control various communication processes according to protocols such as TCP / IP, UDP, and SIP. As shown in FIG. 2, the control unit 60 includes an interface driver 61, a LAN side IP packet processing unit 62, a communication control unit 63, and a WAN side IP packet processing unit 64.

  The interface driver 61 is driver software that controls the interface unit 70. The LAN side IP packet processing unit 62 performs appropriate processing on the packet received from the LAN 10 and outputs the packet to the communication control unit 63. The WAN-side IP packet processing unit 64 performs appropriate processing on the packet received from the WAN 80 and outputs the packet to the communication control unit 63.

  The communication control unit 63 determines the transmission destination of the received packet based on the information indicated by the packet and the information stored in the storage unit 50, and transmits the transmission destination to the determined transmission destination. Moreover, the communication control part 63 can update the memory content of the memory | storage part 50 based on the information received from the other terminal.

  The storage unit 50 is composed of, for example, a hard disk or a nonvolatile RAM, and can store various data. The storage unit 50 includes a relay group information storage unit 51, a relay server information storage unit 52, a client terminal information storage unit 53, a VPN group information storage unit 54, and an address filter information storage unit 55. Hereinafter, the configuration of the storage unit 50 will be described with reference to FIGS. FIG. 3 is a diagram showing the contents of the relay group information. FIG. 4 is a diagram showing the contents of the relay server information. FIG. 5 is a diagram showing the contents of the client terminal information. FIG. 6 is a diagram showing the contents of VPN group information. FIG. 7 is a diagram showing the contents of the address filter information.

  The relay group information storage unit 51 stores relay group information indicating a relay group and a relay server that constitutes the relay group.

  As shown in FIG. 3, in the relay group information, a group tag and a site tag of a child element whose parent element is the group tag are described. In the group tag, group information 511 related to the relay group is described. As the group information 511, relay group identification information (“id”), last update time (“lastmod”), and relay group name (“name”) are described. In the site tag, group configuration information 512 related to the relay server that configures the relay group is described. In this group configuration information 512, identification information (“id”) of the relay server is described. Further, additional relay groups can be created. In this case, unique identification information different from other relay groups is given to the new relay group. As a result, settings such as data exchange only within a specific relay group are possible.

  Note that this relay group information is shared among the relay servers 1, 2, 3, and 4 constituting the relay group. When a process for changing a relay group is performed in a certain relay server, the fact is transmitted to the other relay server and the relay group information is updated. In this way, relay group information is dynamically shared.

  The relay server information storage unit 52 stores relay server information indicating an outline of a relay server that performs relay communication and a client terminal that belongs to the relay server.

  In the relay server information shown in FIG. 4, a site tag described for each relay server and a node tag of a child element whose parent element is the site tag are described. In the site tag, server information 521 regarding the relay server 1 is described. As the server information 521, relay server identification information (“id”), a relay server name (“name”), and activation information (“stat”) are described. When the content of stat is “active”, it indicates that the relay server is logged in to the relay communication system 100, and when stat is blank, it indicates that the log-off is being performed. In a node tag that is a child element of the site tag, affiliation information 522 indicating a client terminal belonging to the relay server is described. The belonging information 522 includes the name of the relay group to which it belongs (“group”), the identification information of the client terminal (“id”), the name of the client terminal (“name”), and the identification information of the login destination relay server. ("Site"). When the client terminal is not logged in to the relay server (relay communication system 100), “site” is blank.

  Note that the communication by the relay group is performed as follows based on the relay group information and the relay server information. For example, when a packet is transmitted from the client terminal 11 to the client terminal 21, first, the client terminal 11 transmits the packet to the relay server 1, which is a relay server to which the client terminal 11 is connected. Note that the relay server capable of exchanging packets is known based on the relay group information, and the identification information of the client terminals belonging to the relay server and the possibility of connection are known based on the relay server information. Based on these pieces of information, the relay server 1 transmits a packet to the relay server 2 that is a relay server to which the client terminal 21 is connected. Then, the relay server 2 transmits a packet to the client terminal 21. In this way, relay communication can be performed between client terminals.

  As with the relay group information, the relay server information is shared between the relay servers 1, 2, 3, and 4 constituting the relay group. When a process for changing the relay server information is performed in a certain relay server, the fact is transmitted to the other relay server and the relay server information is updated. In this way, the relay server information is dynamically shared.

  The client terminal information storage unit 53 stores client terminal information that is detailed information about the client terminal. Note that the relay servers 1, 2, 3, and 4 store only client terminal information related to client terminals belonging to the relay server. For example, since the client terminal 11 belongs to the relay server 1 as shown in FIG. 1, only the client terminal information of the client terminal 11 is stored in the client terminal information storage unit 53 provided in the relay server 1. Yes.

  The client terminal information stored in the client terminal information storage unit 53 of the relay server 1 is shown in FIG. Similarly, the client terminal information stored in the relay server 2 is shown in FIG. 5B, the client terminal information stored in the relay server 3 is shown in FIG. 5C, and the client terminal information stored in the relay server 4 is shown in FIG. Each is shown in d).

  In the client terminal information shown in FIG. 5, a node tag is described. The node tag includes a private IP address (“addr”) of the client terminal, a name of the relay group to which the client terminal belongs (“group”), identification information (“id”), a name (“name”), a relay A password for logging in to the server (“pass”) and port information (“port”) are described.

  The VPN group information storage unit 54 stores VPN group information, which is information relating to a VPN group configured by a device selected from a relay server and a client terminal (hereinafter referred to as a routing device) configuring the relay group. A VPN group is a group configured in a relay group, and a virtual network can be constructed by establishing a routing session between routing devices.

  In the VPN group information shown in FIG. 6, a vnet tag is described. In this vnet tag, VPN group basic information 541, routing point information 542, and routing session information 543 are described. The VPN group basic information 541 includes a relay group name (“group”) to which the VPN group belongs, a VPN group identification information (“id”), a last update time (“lastmod”), and a VPN group name. ("Name"). The routing point information 542 describes identification information of a routing device that performs routing when communication is performed between VPN groups. In the example of FIG. 6, a client terminal 11, a client terminal 21, and a relay server 3 are described as routing devices. The routing session information 543 describes routing devices connected to each other in the VPN group. In the routing session information 543, the routing device performs communication control first (“sp (start point)”) in the routing session establishment process for starting VPN in the VPN group, and the side receiving the communication control “ ep (end point) ". In the following description, a routing device that first performs communication control for establishing a routing session may be referred to as a “start point”, and a routing device that receives the communication control may be referred to as a “end point”.

  As with the relay server information and the relay group information, the VPN group information is also shared between the relay servers 1, 2, and 3 constituting the VPN group. When a process for changing the VPN group information is performed in a certain relay server, the fact is transmitted to the other relay servers constituting the VPN group, and the VPN group information is updated. In this way, VPN group information is dynamically shared. The process for creating this VPN group will be described later.

  The address filter information storage unit 55 stores address filter information indicating a partner that can be designated by the routing device as a packet transmission destination when the routing device performs routing after starting the VPN.

  FIG. 7A shows the contents of the address filter information associated with the routing device. As shown in FIG. 7A, the client terminal 11 can transmit a packet to the processing device 12. The client terminal 21 can transmit a packet to the processing device 22 and the processing device 23. The relay server 3 can transmit a packet to all devices connected to the LAN 30.

  As shown in FIG. 7B, the address filter information storage unit 55 stores the identification information of the routing device and the IP address and name of the other party that can be designated as the packet transmission destination by the routing device in association with each other. is doing. The name of the other party that can be specified as the packet transmission destination can be set to an arbitrary name such as a name that can be easily recognized by the user. For example, the name can be set in consideration of the location where the device and the LAN are arranged. Each routing device can display the address filter information on a display or the like. The address filter information is configured to be exchanged between routing devices when VPN is started.

  The relay servers 1, 2, 3, 4 are configured as described above. Although detailed description of the configuration of the client terminals 11, 21, 31, and 41 is omitted, the storage unit 50 and the control unit 60 are configured substantially the same as the relay servers 1, 2, 3, and 4. ing.

  Next, a process for constructing a VPN group and performing packet routing with the constructed VPN group will be described.

  First, the flow when building a VPN group will be described with reference to FIGS. FIG. 8 is a flowchart showing processing for creating a VPN group. FIG. 11 is a sequence diagram illustrating a communication process for creating a VPN group and a communication process for updating address filter information.

  A user using the relay communication system 100 can display a VPN group setting screen by operating the client terminals 11, 21, 31, and the like. Here, a case where setting is performed using the client terminal 11 will be described. On the setting screen displayed on the client terminal 11, a plurality of relay groups to which the client terminal 11 belongs are displayed. The user selects a relay group in which a VPN group is to be constructed from the plurality of relay groups (S101).

  When a relay group is selected, a list of identification information of relay servers and client terminals that belong to the selected relay group and that can function as a routing point is displayed on the screen of the client terminal 11 (S102). Then, the user selects identification information of a relay server and a client terminal that function as a routing point in the VPN group to be constructed (S103). In this description, it is assumed that the identification information of the client terminal 11, the client terminal 21, and the relay server 3 is selected by the user.

  Then, routing session information is created based on the selected routing point (S104). Further, the identification information of the routing point is created based on the identification information of the selected relay server or the like (S104). The VPN group information shown in FIG. 6 is created by adding VPN group identification information or the like to the created information, and the VPN group information storage unit 54 stores the VPN group information (S105).

  Then, the client terminal 11 sends the created VPN group information to other routing devices (the client terminal 21 and the relay server 3) (S106), thereby notifying that the VPN group has been created. The VPN group information is transmitted to the client terminal 21 via the relay server 1 and the relay server 2 as shown in FIG. 11 (sequence number 1, createVpnGroup). The VPN group information is transmitted to the relay server 3 via the relay server 1 (sequence number 2, createVpnGroup).

  Thereby, the construction process of the VPN group is completed. As described above, in this embodiment, communication between devices may be performed via the relay servers 1, 2, 3, and 4. In the following description, the relay servers 1, 2, and 3 are used. , 4 may be omitted, and may be described as “the client terminal 11 transmits to the client terminal 21”.

  Next, the flow when VPN is started in the constructed VPN group will be described with reference to FIGS. FIG. 9 is a flowchart showing the first half of the process for starting the VPN. FIG. 10 is a flowchart showing the latter half of the process for starting VPN. FIG. 12 is a sequence diagram illustrating a communication process for establishing a routing session and a communication process for transmitting a packet.

  The user can display the constructed VPN group on the screen by operating the client terminals 11 and 21 and the like. Then, by selecting an appropriate VPN group from the displayed VPN groups (S201), a process for starting the VPN can be performed. In this description, it is assumed that the user operates the client terminal 11 and selects the VPN group created above (VPN group having the client terminal 11, the client terminal 21, and the relay server 3 as routing devices).

  The client terminal 11 first reads address filter information associated with itself (S202). As shown in FIG. 7, the address filter information associated with the identification information of the client terminal 11 describes that the packet can be transmitted to the processing device 12. Next, the client terminal 11 reads out the routing points belonging to the selected VPN group (S203). Thereby, the identification information of the client terminal 21 and the relay server 3 is read based on the contents of the VPN group information shown in FIG.

  Based on the relay server information, the client terminal 11 first determines whether or not the client terminal 21 is logged in (whether the relay server identification information is described in “site” or is blank) (S204). . According to the relay server information shown in FIG. 4, since the client terminal 21 is logged in, the client terminal 11 transmits a VPN group start command to the client terminal 21 (sequence number 3, startVpn in FIG. 11). At this time, the identification information (VpnGroupID) of the selected VPN group and the address filter information (addr01) associated with the identification information of the client terminal 11 are also transmitted simultaneously.

  Thereby, the client terminal 21 can specify the VPN group that performs the start process, and can acquire the latest address filter associated with the identification information of the client terminal 11. Further, the client terminal 21 notifies the client terminal 11 that the signal has been received, and transmits address filter information (addr02) associated with the client terminal 11 to the client terminal 11.

  The client terminal 11 receives the response from the client terminal 21 (S206), and stores the received address filter information in the address filter information storage unit 55 (S207). Further, the client terminal 11 registers the client terminal 21 as a routing point that is ready to start VPN (S208).

  Next, the client terminal 11 determines whether there is another routing point (S209). At the time when the VPN start process for the client terminal 21 is completed, the VPN start process is not performed for the relay server 3, so that the client terminal 11 performs the processes of S 204 to S 208 for the relay server 3 this time. . As a result, the client terminal 11 transmits a VPN start command and address filter information to the relay server 3 (sequence number 5, startVpn in FIG. 11). Then, as in the case of the client terminal 21, the address filter information is received from the relay server 3 and stored.

  The transmission / reception of the VPN group start command and the address filter information is also performed between the client terminal 21 and the relay server 3 (sequence number 4, startVpn). As described above, the client terminal 11, the client terminal 21, and the relay server 3 can acquire the address filter information of other routing points.

  As described above, when starting VPN, each routing device exchanges (acquires) address filter information with other routing devices, and can construct a VPN using the latest address filter information. Therefore, even if the address filter information is changed in some routing devices at the stage before the VPN start, the VPN can be started in a state in which the change is reflected in all the routing devices. Can be prevented and reliability can be improved.

  Next, the client terminal 11 extracts the routing session information stored in the VPN group information storage unit 54 (S210), and determines whether a routing session starting from itself is described (S211). The routing session information in FIG. 6 describes that the client terminal 11 is the starting point in the routing session to be established between the client terminal 21 and the relay server 3.

  Therefore, first, the client terminal 11 selects the client terminal 21, and determines whether or not the client terminal 21 is a routing point that is ready to start VPN (S212). Since the client terminal 21 has been prepared by S208 described above, communication control for establishing a routing session from the client terminal 11 to the client terminal 21 is performed (S213, sequence number 6, createVpnSsn).

  Next, the client terminal 11 determines whether or not there is another description of the routing session that is the starting point of the connection (S214). At the time when the routing session establishment process for the client terminal 21 is completed, since the routing session establishment process with the relay server 3 is not performed, the client terminal 11 has also performed the relay server 3 on the client terminal 21. Communication similar to the communication is performed (sequence number 8, createVpnSsn). Thereby, a routing session is established between the client terminal 11 and the relay server 3.

  Further, as shown in FIG. 6, since the routing session information describes that the client terminal 21 should be the starting point of the routing session with the relay server 3, the communication control for establishing the routing session is This is also performed from the client terminal 21 to the relay server 3 (sequence number 7, createVpnSsn). As described above, routing sessions can be established between the client terminal 11 and the client terminal 21, between the client terminal 11 and the relay server 3, and between the client terminal 21 and the relay server 3, respectively. Thereafter, packet routing control is started (S215). Each routing device does not perform the initial communication control for establishing a routing session unless the routing session information indicates that it is the starting point. The routing session can be established with simple control.

  Next, processing for routing a packet using an established routing session will be described with reference to FIGS. Hereinafter, processing performed by the client terminal 11 when the client terminal 11 functioning as a routing point receives three types of packets from the first packet to the third packet from the processing device 12 will be described.

  First, the case where the first packet whose destination IP address is (192.168.2.22) is received (sequence number 9, packet 01) will be described. After receiving the first packet, the client terminal 11 compares the destination IP address with the address filter information shown in FIG. And the routing point which can transmit a packet with respect to the destination described in the 1st packet is detected.

  As shown in FIG. 7, the destination IP address of the first packet is included in the address filter information associated with the identification information of the client terminal 21. In this case, the client terminal 11 transmits the first packet to the client terminal 21 via a routing session established with the client terminal 21.

  Similarly to the client terminal 11, the client terminal 21 that has received the first packet compares the destination IP address with the address filter information. Then, it detects that itself is described as a routing point capable of transmitting the packet to the destination described in the first packet. In this case, the first packet is transmitted to the destination processing device 22.

  Next, a case where the client terminal 11 receives the second packet whose destination IP address is (192.168.3.32) (sequence number 10, packet 02) will be described. According to the address filter information of FIG. 7, the relay server 3 is designated as a routing point capable of transmitting a packet to the destination described in the second packet. Therefore, the client terminal 11 transmits the second packet to the relay server 3 via the routing session established with the relay server 3. Then, the relay server 3 detects that it is described as a routing point capable of transmitting the packet to the destination described in the second packet, and transmits the second packet to the processing device 32 of the destination. To do.

  Next, the case where the client terminal 11 receives the third packet whose destination IP address is (192.168.5.51) (sequence number 11, packet 03) will be described. As a result of comparing the destination IP address and the address filter information, the client terminal 11 detects that a routing point capable of transmitting a packet to the destination is not described. In this case, the client terminal 11 does not transmit the received third packet anywhere.

  As described above, in the present embodiment, the routing target data is flowed in the routing session of the application layer. Therefore, the routing described above is different from normal IP routing.

  By performing routing in the application layer in this manner, remote LANs can communicate with each other using private IP addresses without being aware of the WAN. In addition, as described above, the address filter information storage unit 55 can display the names of counterparts that can be specified as packet transmission destinations. Therefore, the user can easily recognize to which device the packet can be transmitted using the VPN.

  Next, a process for terminating the VPN will be described with reference to FIG. FIG. 13 is a sequence diagram illustrating a communication process for terminating a VPN group. The user can start the process of terminating the VPN by operating the client terminals 11 and 21 and the like. In this description, it is assumed that the user operates the client terminal 11 to start processing for terminating the VPN.

  When the client terminal 11 receives the instruction to end the VPN, the client terminal 11 transmits the fact to the client terminal 21 and the relay server 3 together with the VPN group identification information (sequence numbers 12, 13, stopVpn). Note that the client terminal 21 and the relay server 3 can know which VPN group the VPN is to be terminated by, based on the VPN group identification information received from the client terminal 11.

  The client terminal 11 transmits a routing session end command to the client terminal 21 after receiving a signal indicating that the VPN end is accepted from the client terminal 21 and the relay server 3 (sequence number 14, closeVpnSsn). Further, the client terminal 11 also transmits a routing session end command to the relay server 3 (sequence number 16, closeVpnSsn).

  The routing session end command is also transmitted from the client terminal 21 to the relay server 3 (sequence number 15, closeVpnSsn). As described above, the routing sessions established between the client terminal 11 and the client terminal 21, between the client terminal 11 and the relay server 3, and between the client terminal 21 and the relay server 3 can be terminated. And VPN by a VPN group is complete | finished.

  Next, the client terminal (first communication device) 21 logged in to the relay communication system 100 via the relay server (second relay server) 2 logs out, and uses the same identification information to identify the client terminal (second Communication processing when logging in from the communication device 41 via the relay server 4 will be described with reference to FIGS. Since the client terminal 21 and the client terminal 41 are connected to different LANs, in the following description, login from the client terminal 21 is “normal login” and login from the client terminal 41 is “remote login”. , May be called each.

  FIG. 14 is a sequence diagram illustrating communication processing when remote login is performed. FIG. 15 is a sequence diagram illustrating communication processing when a packet is transmitted via the client terminal 41 during remote login. Of the processes described below, the processes equivalent to the processes described above (the processes shown in FIGS. 11 to 13) may be omitted or simplified.

  First, in a state where normal login from the client terminal 21 is performed, the user operates the client terminal 11 to instruct creation of a VPN group, and the client terminal 11 and the client terminal 21 serve as routing points of the VPN group. , And the relay server 3 are selected. In this case, the client terminal 11 transmits VPN group information relating to the VPN group created by the user to the client terminal 21 and the relay server 3 in the same manner as in FIG. 11, and notifies that the VPN group has been created. (Sequence numbers 21 and 22 in FIG. 14, createVpnGroup).

  Then, it is assumed that the client terminal 21 that has been logging in normally logs off from the relay server 2 after notification of creation of the VPN group (sequence number 23). In this case, the relay server 2 notifies the other communication devices (relay server 1, client terminal 11, and relay server 3) constituting the relay group that the client terminal 21 is logged off (sequence numbers 24, 25, notify). logoff). Upon receiving this notification, the communication device performs processing for deleting the login information (“site”) of the client terminal 21 in the relay server information storage unit 52. As a result, the content of “site” is cleared from the fact that the identification information “relay-server-2@abc.net” of the relay server 2 is described, and becomes blank.

  Here, it is assumed that login is performed from the client terminal 41 connected to the LAN 40 to the relay communication system 100 using the identification information (CLIENT-21@relayserver2.abc.net) set in the client terminal 21 (sequence). Number 26, remoteLogin). Since the password corresponding to this identification information is stored only in the client terminal information storage unit 53 of the relay server 2, the relay server 4 sends the input identification information (ID) and password (PWD) to the relay server 2. (Sequence number 26.1, remoteLogin). If the relay server 2 authenticates that the identification information and the corresponding password are correct, the remote login is successful.

  When the remote login is successful, the relay server 4 uses the identification information set in the client terminal 21 to indicate that the login has been performed from the client terminal 41 to the relay communication system 100 and other communication devices (relay server). 3, relay server 2, relay server 1, and client terminal 11) (sequence numbers 27, 28, 29, notify remoteLogin). Upon receiving this notification, the communication device uses the information indicating the relay server of the login destination corresponding to this identification information in the affiliation information 522 stored in the relay server information storage unit 52 (content of “site” that is blank). Then, the identification information “relay-server-4@abc.net” of the relay server 4 is written.

  After remote login, the user sets address filter information at the client terminal 41. Then, as shown in FIG. 16A, it is assumed that the client terminal 41 is set to be able to transmit a packet to the processing device 42. The identification information used for remote login from the client terminal 41 is the same as the identification information used for normal login from the client terminal 21. Accordingly, the identification information of the routing device in the content stored in the address filter information storage unit (the content shown in FIG. 16B) includes the identification information set in the client terminal 21 (“client-21 @ relay-server2. abc.net ").

  Next, the flow when VPN is started in the state after the remote login will be briefly described. When the user instructs the client terminal 11 to start VPN, the client terminal 11 transmits address filter information and a VPN group start command associated with itself to the client terminal 41 (sequence number 30). , StartVpn). Upon receiving this notification, the client terminal 41 returns the address filter information associated with itself to the client terminal 11 together with the reception of the start command. The above process is also performed between the client terminal 11 and the relay server 3 (sequence number 32, startVpn).

  In addition, the client terminal 41 transmits the address filter information associated with itself and the VPN group start command to the relay server 3 (sequence number 31, startVpn). Receiving this notification, the relay server 3 returns the address filter information associated with itself to the client terminal 41 together with the reception of the start command.

  As described above, the client terminal 11 and the relay server 3 perform the processing performed on the client terminal 21 in FIG. 11 and FIG. On the other hand, the client terminal 41 performs the process performed via the relay server 2 in FIGS. 11 and 12 via the relay server 4. As a result, the client terminal 11 and the relay server 3 can acquire the address filter information newly set in the client terminal 41.

  Then, the routing session is established (sequence numbers 33, 34, and 35, createVpnSsn) in the same manner as at the start of VPN during normal login. When establishing a routing session between the routing point (client terminal 11 and relay server 3) that was the connection partner of the client terminal 21 at the time of normal login and the client terminal 41 that has been remotely logged in, both devices The communication between them is performed via the relay server 4 related to the LAN 40 to which the client terminal 41 that is remotely logged in is connected (sequence numbers 33 and 34). Thereafter, packet routing control for VPN is started.

  In the VPN constructed in this way, the case where the client terminal 11 receives the fourth packet whose destination IP address is (192.168.4.42) from the processing device 12 (sequence number 36, packet 04) will be described. In this case, as shown in FIG. 16, the client terminal 41 (identification information set in the client terminal 21) is designated as a routing point capable of transmitting the packet to the destination described in the fourth packet. . Accordingly, the client terminal 11 transmits the fourth packet to the client terminal 41 through the routing session established with the client terminal 41. Then, the client terminal 41 detects that it is described as a routing point capable of transmitting the packet to the destination described in the fourth packet, and transmits the fourth packet to the processing device 42 of the destination. To do.

  As described above, in the present embodiment, even when remote login is performed, a new VPN can be easily constructed by effectively utilizing the information of the VPN group created at the time of normal login. .

  As described above, the relay server 3 of this embodiment includes the relay group information storage unit 51, the relay server information storage unit 52, the VPN group information storage unit 54, the address filter information storage unit 55, and the communication control. Unit 63. The relay group information storage unit 51 stores information on relay groups including other relay servers (relay servers 1, 2, 4) that can be connected to each other (the relay server 3). The relay server information storage unit 52 stores relay server information including start information of relay servers belonging to the relay group and start information and registration information of client terminals connected to the relay servers belonging to the relay group. The VPN group information storage unit 54 relates to a VPN group that performs communication by VPN via a communication device set as a routing point among communication devices that constitute the relay communication system 100, and identification information of the routing device that constitutes the VPN group And routing session information 543 including information on routing devices connected to each other. The address filter information storage unit 55 stores address filter information indicating a partner that can be designated by the routing device as a packet transmission destination in association with identification information of the routing device. The communication control unit 63 controls the sharing of information stored in the VPN group information storage unit 54 between routing devices, and transmits address filter information to other routing devices when starting VPN in the VPN group, The address filter information is received from other routing devices, and the stored contents of the address filter information storage unit 55 are updated based on the address filter information. Based on the routing session information stored in the VPN group information storage unit 54, Control that establishes a routing session for routing packets, and control that, after establishing a routing session, refers to a peer that can be specified as a destination by a routing device based on address filter information, and performs routing based on the contents , The line .

  As a result, the relay server 3 can construct a VPN with the client terminal 11 and the client terminal 21 selected from other communication devices constituting the relay communication system, and share files. Further, the relay server 3 acquires address filter information from the client terminal 11 and the client terminal 21 when starting VPN in the VPN group. Therefore, compared with the case where the VPN is constructed previously, for example, even when the address filter information is changed in the client terminal 11, the VPN can be constructed flexibly in response to such a change in the situation. .

  Further, in the relay server 3 of the present embodiment, the VPN group information storage unit 54 receives the identification information of the routing device (starting point) on the side that performs the communication control for establishing the routing session first, and the communication control. And the identification information of the routing device (end point) on the side.

  Thus, when starting a VPN in a VPN group, in order to establish a routing session between two mutually connected routing devices, it is possible to predefine which routing device performs communication control first. it can. Therefore, communication control collision can be prevented.

  In addition, when the destination of the received packet is specified in the address filter information associated with its own identification information, the relay server 3 of the present embodiment transmits the packet to the destination. When the destination of the received packet is specified in the address filter information associated with the identification information of the routing device other than itself, the relay server 3 establishes a routing session established between itself and the routing device. The packet is transmitted to the routing device via The relay server 3 does not transmit the packet when the destination of the received packet is not specified in the address filter information associated with the identification information of the routing device.

  Thereby, the relay server 3 can perform routing appropriately based on the address filter information.

  In the present embodiment, the client terminal 41 connected to the WAN 80 via the relay server 4 starts from the first state where the client terminal 21 connected to the WAN 80 via the relay server 2 forms a VPN group. Consider the case of switching to the second state constituting the VPN group. In this case, the communication control unit 63 in the relay server 4 is configured so that the client terminal 21 in the first state and the client terminal 41 in the second state have the same identification information (that is, the second state is (When remote login), when starting the virtual private network in the second state, the client terminal 11 and the relay server 3 to which the client terminal 21 is connected in the first state, and the client terminal 41 In the meantime, control is performed to establish a routing session via the relay server 4 (sequence numbers 33 and 34).

  Thereby, it is possible to construct a VPN that can flexibly cope with the case where the configuration of the VPN group changes beyond the relay server. In addition, the VPN group information in the first state can be effectively used to easily construct the VPN in the second state.

  In the present embodiment, the address filter information storage unit 55 can store the name of a partner that can be designated by the routing device as a packet transmission destination.

  Thereby, for example, when referring to the address filter information, the user can know not only the IP address of the partner to which the packet can be transmitted but also the name at the same time.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  The format for storing the relay group information, relay server information, client terminal information, VPN group information, address filter information, etc. is not limited to the XML format, and each information can be stored in an appropriate format.

  Instead of the configuration of the above-described embodiment, an external server used for communication between each relay server may be installed on the Internet, and a communication may be performed by exhibiting a function as a SIP (Session Initiation Protocol) server. .

1, 2, 3, 4 Relay server 11, 21, 31, 41 Client terminal 10, 20, 30, 40 LAN
50 storage unit 60 control unit 63 communication control unit 100 relay communication system

Claims (6)

A relay group information storage unit that stores information of a relay group including other relay servers that can be connected to each other;
A relay server information storage unit for storing relay server information including start information of the relay server belonging to the relay group and start information and registration information of a client terminal connected to the relay server belonging to the relay group;
Consists of a routing device that is a communication device set as a routing point among communication devices that constitute a relay communication system based on the relay group information and the relay server information, and communicates with the virtual private network via the routing device. A VPN group information storage unit for storing identification information of the routing devices constituting the VPN group and connection information indicating the routing devices connected to each other with respect to the VPN group to be performed;
An address filter information storage unit that stores address filter information indicating a partner that can be designated by the routing device as a packet transmission destination in association with identification information of the routing device;
Control for sharing the information stored in the VPN group information storage unit between the routing devices, and when starting a virtual private network in the VPN group, the address filter information is transmitted to the other routing devices and The address filter information is received from the routing device, and the content stored in the address filter information storage unit is updated based on the address filter information, and a packet is generated based on the connection information stored in the VPN group information storage unit. Control to establish a routing session for routing the device, and after establishing the routing session, the routing device refers to a partner that can be designated as a destination based on the address filter information, and performs routing based on the content. Cormorants and control, and a communication control unit that performs,
A relay server comprising: The relay server according to claim 1,
The VPN group information storage unit includes, as the connection information, identification information of the routing device on the side that first performs communication control for establishing a routing session, and identification information of the routing device on the side that receives the communication control, , And storing the relay server. The relay server according to claim 1 or 2,
The communication control unit
When the destination of the received packet is specified in the address filter information associated with its own identification information, the packet is transmitted to the destination,
When the destination of the received packet is specified in the address filter information associated with the identification information of the routing device other than itself, via a routing session established between itself and the routing device Send the packet to the routing device,
A relay server, wherein a packet is not transmitted when a destination of a received packet is not designated in the address filter information associated with identification information of the routing device. A relay server according to any one of claims 1 to 3,
From the first state in which the first communication device, which is the routing device connected to the wide area communication network via the second relay server, constitutes a VPN group,
The second communication device connected to the wide area network through itself switches to the second state constituting the VPN group,
When the first communication device in the first state and the second communication device in the second state have the same identification information,
When the communication control unit starts the virtual private network in the second state, the communication control unit is interposed between the connection partner of the first communication device in the first state and the second communication device. A relay server characterized by performing control to establish a routing session. The relay server according to any one of claims 1 to 4, wherein
The relay server characterized in that the address filter information storage unit is capable of storing a name of a partner that can be designated by the routing device as a packet transmission destination. Multiple relay servers,
A client terminal connectable to each other via the relay server;
With
The relay server is
A relay group information storage unit that stores information of a relay group including other relay servers that can be mutually connected to the relay server;
A relay server information storage unit for storing relay server information including start information of the relay server belonging to the relay group, start information and registration information of the client terminal;
Identification information of the routing device constituting the VPN group with respect to the VPN group configured by the routing device set as a routing point among the relay server and the client terminal and performing communication through the virtual private network via the routing device A VPN group information storage unit for storing connection information indicating the routing devices connected to each other;
An address filter information storage unit that stores address filter information indicating a partner that can be designated by the routing device as a packet transmission destination in association with identification information of the routing device;
Control for sharing the information stored in the VPN group information storage unit between the routing devices, and when starting a virtual private network in the VPN group, the address filter information is transmitted to the other routing devices and The address filter information is received from the routing device, and the content stored in the address filter information storage unit is updated based on the address filter information, and a packet is generated based on the connection information stored in the VPN group information storage unit. Control to establish a routing session that can be routed, and after the establishment of the routing session, the routing device refers to a partner that can be designated as a transmission destination based on the address filter information, and performs routing based on the contents. Cormorants and control, and a communication control unit that performs,
A relay communication system comprising:

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