JP4998526B2 - Relay server and relay communication system - Google Patents

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 system called a virtual private network (VPN) is known. This VPN is used for, for example, applications in which client terminals connected to a plurality of LANs communicate with each other via the Internet to remotely maintain a certain client terminal. If the VPN is used, a client terminal to be maintained can receive remote maintenance or the like from a device connected to another remote LAN.

  Patent Document 1 discloses a management system via this type of network. This management system is constructed so as to straddle building owners, equipment maintenance companies, and electrical equipment manufacturers. The building owner installs electrical equipment and an operation control management device for controlling the electrical equipment in the building owned by the building owner. This operation control management device is configured to be accessible via a network such as the Internet. The equipment maintenance company is entrusted with the management of the electrical equipment by the building owner, and has obtained permission from the electrical equipment manufacturer to access the operation control management device. Therefore, the equipment maintenance company can manage the electrical equipment from a remote location via a network such as the Internet.

JP 2003-223521 A

  By the way, in the case of dealing with troubles occurring at customers by remote maintenance via the communication system as described above, if the maintenance person is unable to deal with the trouble, it means that he / she will take over the correspondence to the upper manager. Has been done (so-called escalation).

  Such escalation is generally performed in response to a help request from a maintenance person. In other words, the upper manager is in a passive state regarding escalation, and it is not so often that the upper manager side actively issues an escalation request.

  The reason for this is that in a remote maintenance service using a conventional communication system, the maintenance manager accurately knows what maintenance personnel are doing with which customers. It is thought that it is difficult. In particular, when the upper manager and the maintenance staff belong to different service bases, it is more difficult for the upper manager to accurately grasp the work status of the maintenance staff.

  The present invention has been made in view of the above circumstances, and its main object is to provide a relay communication system in which other relay servers can easily grasp the connection status between relay servers. 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. In other words, this relay server is a relay server with a management function that includes an access permission information storage unit, a connection status notification reception unit, a communication management information storage unit, and a communication management information transmission unit. The access permission information storage unit stores, for each managed relay server, access permission information that stores other managed relay servers that are permitted to access the managed relay server . The connection status notification receiving unit, when a data communication session is established between the managed relay servers, at least a connection status notification for notifying start and end of the data communication session, and managing the data communication session Received from the target relay server. The communication management information storage unit stores communication management information in which the content of the connection status notification received by the connection status notification reception unit and the managed relay server configuring the data communication session are stored in association with each other. When the communication management information transmission unit receives a request for communication management information from a certain managed relay server, the communication management information related to the managed relay server that permits access to the managed relay server of the communication management information request source Is extracted and transmitted to the managed relay server that is the source of the communication management information request.

  Thereby, the access permission information and the communication management information can be centrally managed by the relay server with a management function without being distributed to a plurality of relay servers. As a result, the managed relay server that is the management target of the relay server with management function transmits the communication management information related to other managed relay servers permitted to access from the managed relay server to the relay server with management function. It can be acquired simply by communicating. Therefore, the managed relay server that has acquired the communication management information can easily grasp which managed relay server is currently communicating.

  The relay server is preferably configured as follows. That is, the relay server includes a session establishment request source notification unit. The session establishment request source notifying unit is a case where a first data communication session is established between managed relay servers, and the managed relay server that does not constitute the first data communication session is the first data communication session. When a second data communication session is to be established with one of the managed relay servers constituting the data communication session, the session from the managed relay server that is the establishment request source of the second data communication session The establishment request is received, and at least one of the managed relay servers constituting the first data communication session is notified of the managed relay server that is the establishment request source of the second data communication session To do.

  Thus, it is possible to notify in advance that another relay server is trying to connect to the relay server in which the data communication session is established. Therefore, the relay server constituting the previously established data communication session can appropriately process a new connection request.

According to a second aspect of the present invention, a relay server having the following configuration is provided. That is, the relay server includes a connection status notification unit, a communication management information request unit, and a session establishment request unit. The connection status notification unit manages a communication between relay servers, at least a connection status notification for notifying the start and end of the data communication session when a data communication session is established with another relay server. The information is transmitted to the relay server with function, thereby recording the communication management information in the relay server with management function. The communication management information request unit requests the communication management information from the relay server with a management function. The session establishment request unit, the communication management information related to the managed relay server is permitted to communicate with itself, after the management function with the relay server to the receiver, any of which is recorded in the communication management information A session establishment request with the relay server as a partner can be transmitted to the relay server with management function.

  That is, since the communication management information is centrally managed in the relay server with a management function, the relay server of the present invention transfers the communication management information related to the relay server permitted to access from the relay server to the relay server with the communication management function. It can be obtained simply by communicating with the server. And in the relay server of this invention, after receiving communication management information, the session establishment request | requirement to the other relay server described in the said communication management information can be made. Therefore, for example, it is possible to select a partner relay server that requests establishment of a session based on the content of the communication management information.

  The relay server is preferably configured as follows. That is, when a relay server that has established a first data communication session with another relay server is identified based on the communication management information, the first data communication session with the established relay server Before the second data communication session is established between them, it is possible to perform message communication with any of the relay servers constituting the first data communication session.

  Whether or not a relay server that has established a data communication session with another relay server is inquired of the current status by message communication, and a new data communication session is established according to the response result. It can be determined whether or not. For example, if the data communication session between relay servers is used for remote maintenance, the progress of the maintenance work is inquired by the message communication, and the help for the maintenance work is required based on the response result It can be determined whether or not. When it is determined that help is necessary, it is possible to actively participate in remote maintenance work, such as newly establishing a data communication session and participating in the maintenance work.

According to the 3rd viewpoint of this invention, the relay communication system of the following structures is provided. That is, the relay communication system includes a relay server with a management function and a plurality of management target relay servers that are managed by the relay server with a management function. The relay server with a management function is a relay server with a management function including an access permission information storage unit, a connection status notification reception unit, a communication management information storage unit, and a communication management information transmission unit. The access permission information storage unit stores, for each managed relay server, access permission information that stores other managed relay servers that are permitted to access the managed relay server . The connection status notification receiving unit, when a data communication session is established between the managed relay servers, at least a connection status notification for notifying start and end of the data communication session, and managing the data communication session Received from the target relay server. The communication management information storage unit stores communication management information in which the content of the connection status notification received by the connection status notification reception unit and the managed relay server configuring the data communication session are stored in association with each other. When the communication management information transmission unit receives a request for communication management information from a certain managed relay server, the communication management information related to the managed relay server that permits access to the managed relay server of the communication management information request source Is extracted and transmitted to the managed relay server that is the source of the communication management information request.

  In this relay communication system, access permission information and communication management information can be centrally managed by a relay server with a management function without being distributed to a plurality of relay servers. As a result, the managed relay server that is the management target of the relay server with management function transmits the communication management information related to other managed relay servers permitted to access from the managed relay server to the relay server with management function. It can be acquired simply by communicating.

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 an external server. The functional block diagram of a call center server. The figure which shows the content of client terminal information. The figure which shows the content of relay server information. The figure which shows the content of relay group information. A table showing the contents of the access permission information database. A table showing the contents of the communication management information database. Explanatory drawing explaining a routing process. The figure which shows the content of LAN search result information. The figure which shows the content of route search result information. The figure which shows the content of routing group information. The sequence diagram which shows a communication process. The sequence diagram which shows a communication process. The sequence diagram which shows a communication process. The sequence diagram which shows a communication process.

  Next, an embodiment of the invention will be described. FIG. 1 is an explanatory diagram showing the overall configuration of a relay communication system according to an embodiment of the present invention.

  The relay communication system of this embodiment is a remote maintenance system constructed for the purpose of remote maintenance of an apparatus or a machine, a call center, an installation destination (customer factory) of the apparatus or machine, a serviceman dispatch destination, Are connected via the Internet.

  The call center is a service base for performing maintenance of the device or machine introduced into the customer factory, and is installed at the manufacturer of the device or machine, for example. Service personnel dispatch destinations (first service man dispatch destination and second service man dispatch destination as shown in FIG. 1) are places where service personnel are dispatched, and are separate from the call center as a base for providing remote maintenance services. Installed. The relay communication system according to the present embodiment is constructed assuming a situation in which a serviceman waiting at a serviceman dispatch destination remotely maintains a device or machine at a customer factory via the Internet.

  As shown in FIG. 1, the relay communication system includes a plurality of LANs 91 to 94 connected to the WAN. A WAN (Wide Area Network) is a network that connects different LANs to each other. In the present embodiment, the Internet is used as the WAN. A LAN (Local Area Network) is a network constructed in a limited place. There are a plurality of LANs, and they are constructed at locations physically separated from each other.

  A LAN (call center LAN) 91 is constructed in the call center, a LAN (dispatch destination LAN) 92 is constructed in the first serviceman dispatch destination, a LAN (customer LAN) 93 is constructed in the customer factory, and a LAN (help source LAN). 94) is constructed in the second serviceman dispatch destination. These four LANs 91, 92, 93, 94 are connected to the Internet, which is a global network.

  In addition, the relay servers 1 are installed in the LANs 91 to 94, respectively. In the following description, in order to distinguish the relay server 1 arranged in each LAN, the relay server 1 arranged in the LAN 91 may be referred to as a call center server (relay server 1) R1. Further, the relay server 1 arranged in the LAN 92 may be called a dispatch server (relay server 2) R2, and the relay server 1 arranged in the LAN 93 may be called a customer server (relay server 3) R3. . Further, the relay server 1 arranged on the LAN 94 can be called a dispatch destination server in the sense that it is arranged at a service person dispatch destination, and this relay server 1 is particularly referred to as a help source server (relay server 4). Sometimes called R4.

  A client terminal 5 for performing various settings for performing relay communication is connected to the call center server R1 via a LAN 91. A client terminal 5 that is directly operated when a serviceman performs remote maintenance is connected to the dispatch destination server R2 and the help source server R4 via a LAN 92 or a LAN 94.

  At the customer factory, a client terminal 5 that is a target for a serviceman to perform remote maintenance is arranged. The client terminal 5 itself at the customer factory may be an apparatus or machine manufactured by the manufacturer, or the client terminal 5 at the customer factory may be merely a control terminal for controlling the apparatus or machine. In any case, the service person provides the remote maintenance service by accessing the client terminal 5 of the customer factory. The client terminal 5 arranged in the customer factory is connected to the customer server R3 via the LAN 93.

  The client terminal 5 connected to each of the LANs 91 to 94 is a terminal that can be directly operated by the user, for example, a personal computer (PC) used for daily work by the user. Accordingly, there are usually a large number of client terminals 5 in the LAN. Each client terminal 5 is assigned a private IP address that is uniquely managed in the same LAN.

  In addition to the call center server R1, the dispatch destination server R2, the customer server R3, and the help source server R4 illustrated in FIG. 1, a LAN is constructed in a physically separated location, and the relay server is connected to the LAN. 1 is arranged. A plurality of these relay servers 1 are connected to the external server 2 via the Internet.

  More specifically, FIG. 1 shows two service personnel dispatch destinations (first service man dispatch destination and second service man dispatch destination), but there are some other dispatch destinations not shown. To do. A LAN is established at each dispatch destination (not shown), and a relay server 1 as a dispatch destination server is connected to the LAN (similar to the LAN 92 and LAN 94 in FIG. 1). In addition, although the LAN 93 is installed at the customer factory shown in FIG. 1, there is a customer factory (customer where a machine or apparatus to be maintained is installed) other than this. A LAN is also installed at each customer factory (not shown), and a relay server 1 as a customer server is connected to the LAN (as in the case of the LAN 93 in FIG. 1).

  And in this embodiment, the relay server 1 as a some dispatch destination server is set for every customer server (relay server 1). In the following description, “relay server 1 as a dispatch destination server” may be simply referred to as “dispatch destination server”, and “relay server 1 as a customer server” may be simply referred to as “customer server”.

  Next, the configuration of the external server 2 will be described. The external server 2 is a device used for communication between the relay servers 1 arranged in each LAN, and is installed on the Internet. The external server 2 of the present embodiment has a function as a SIP (Session Initiation Protocol) server. Specifically, the external server 2 has a function as a SIP proxy server that relays SIP methods and responses, and a function as a SIP registrar server that registers an account of the relay server 1.

  As shown in FIG. 2, the external server 2 includes a WAN interface 201, a control unit 202, and a relay server account information database 203 as main components.

  The WAN interface 201 is an interface that communicates with each device such as the relay server 1 connected to the Internet using a global IP address.

  The relay server account information database 203 is a database that manages the account of the relay server 1 constituting the relay communication system in association with the global IP address. In the relay server account information database 203 of the present embodiment, the account of the call center server R1, the dispatch destination server R2, the customer server R3, and the help source server R4 and the global IP address are registered for each relay server 1 in association with each other. Has been.

  The control unit 202 is a processing unit that controls various communications performed via the WAN interface 201, and controls communication processing according to a protocol such as TCP / IP, UDP, or SIP. For example, the control unit 202 receives information related to the account of the relay server 1 from each relay server 1 and registers the information in the relay server account information database 203. Also, processing such as relaying communication data such as various SIP methods or responses transmitted from the relay server 1 to other relay servers 1 is performed.

  Next, the configuration of the relay server 1 arranged in the LANs 91 to 94 will be described. Each relay server 1 arranged in the LANs 91 to 94 is communicably connected to the client terminal 5 arranged in each LAN and is also connected to the Internet. Each relay server 1 (that is, call center server R1, dispatch destination server R2, customer server R3, and help source server R4) is assigned both a private IP address and a global IP address. As a result, the relay servers 1 can perform relay communication with each other via the external server 2. The relay server 1 has a function as a SIP registrar server, and communication between each relay server 1 and each client terminal 5 is performed using SIP. The communication between each relay server 1 and each client terminal 5 is not limited to the one using SIP, and it is also possible to perform communication according to an appropriate protocol such as TCP / IP or UDP. is there.

  With reference to FIG. 3, the relay server 1 will be described by taking the call center server R1 disposed in the LAN 91 as an example. FIG. 3 is a functional block diagram of the call center server R1.

  As shown in FIG. 3, the call center server R1 includes a LAN interface 501, a WAN interface 502, a control unit 503, a client terminal information database 511, a relay server information database 512, a relay group information database 521, and a routing group. An information database 522, an access permission information database 513, and a communication management information database 515 are provided as main components.

  The LAN interface 501 is an interface that uses a private IP address to communicate with the client terminal 5 connected to the same LAN as its own device.

  The WAN interface 502 is an interface that communicates with each device such as the external server 2 connected to the Internet using a global IP address.

  The control unit 503 is a processing unit that controls various communications performed via the LAN interface 501 and the WAN interface 502, and controls various communication processes according to protocols such as TCP / IP, UDP, and SIP.

  The client terminal information database 511 is a database that manages account information of the client terminal 5 that is locally connected to the call center server R1 via the LAN 91 in association with a private IP address.

  An example of the contents of the client terminal information stored in the client terminal information database 511 is shown in FIG. As shown in FIG. 4, in the client terminal information, for each client terminal 5 connected to the LAN 91, a node tag including attribute information related to the client terminal 5 is described. The attribute information related to the client terminal 5 includes the private IP address (“addr”), identification information (“id”), name (“name”), port information (“port”), and the like of the client terminal 5. Although the description of the client terminals 5 other than the client 11 and the client 12 is omitted in the stored content example illustrated in FIG. 4, in practice, other client terminals 5 (for example, connected to the relay server 1 via the LAN 91 (for example, The attribute information regarding client 13) is also described.

  The relay server information database 512 is a database that manages information on the relay servers 1 that perform relay communication and the client terminals 5 that are connected to the respective relay servers 1.

  An example of storage contents of relay server information stored in the relay server information database 512 is shown in FIG. The relay server information shown in FIG. 5 is a combination of information created in each of the relay servers 1 (call center server R1, dispatch destination server R2, customer server R3, etc.) that perform relay communication. The relay server information is created by the call center server R1 by combining the relay server information created by the call center server R1 itself with each relay server information received from the other relay server 1 that performs relay communication.

  In the relay server information shown in FIG. 5, a site tag described for each relay server 1 and a node tag of a child element having the site tag as a parent element are described. The site tag includes attribute information related to the relay server 1. The attribute information includes identification information (“id”) of the relay server 1, name (“name”) of the relay server 1, and activation information (“stat”). ") Etc. The node tag that is a child element of the site tag includes attribute information related to the client terminal 5 that logs on to the relay server 1. The attribute information related to the client terminal 5 includes the identification information (“id”) of the client terminal 5 and the name (“name”) of the client terminal 5. Although the description of the relay server 1 other than the relay server 1 and the relay server 2 is omitted in the storage content example of FIG. 5, the attribute related to the other relay server 1 (for example, the relay server 3) connected through the external server 2 is actually used. Information is also described. Further, in FIG. 5, as in FIG. 4, a part of the description regarding the client terminal 5 is omitted.

  The relay group information database 521 is a database that manages relay group information for performing relay communication.

  An example of the contents of relay group information stored in the relay group information database 521 is shown in FIG. As shown in FIG. 6, in the relay group information, a group tag and a site tag of a child element having the group tag as a parent element are described. The group tag includes attribute information related to the relay group. Examples of the attribute information include relay group identification information (“id”) and a relay group name (“name”). The site tag includes attribute information related to the relay server 1 included in the relay group, and the attribute information includes identification information (“id”) of the relay server 1 and the like. 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 the relay group are possible.

  The routing group information database 522 is a database that manages routing group information used for performing routing processing using the relay communication system. Details of the routing group information and routing processing using the routing group information will be described later.

  The example of stored contents of client terminal information shown in FIG. 4, the example of stored contents of relay server information shown in FIG. 5, and the example of stored contents of relay group information shown in FIG. 6 are merely examples, and appropriate attribute information Of course, element information can be added or deleted.

  The access permission information database (access permission information storage unit) 513 is a database that manages, for each customer server, identification information and the like of a relay server that is permitted to communicate except for the call center server R1. The customer server here means the relay server 1 including the customer server R3 illustrated in FIG. This access permission information database 513 is configured so that, for example, when a serviceman dispatch destination is in charge of remote maintenance of which customer factory, it is determined in advance so that only the responsible serviceman dispatch destination can perform remote maintenance. This is for restricting access to the customer server.

  The access permission information database 513 will be specifically described with reference to FIG. FIG. 7 is a table showing the contents of the access permission information database 513.

  As described above, the call center server R1 of the present embodiment is connected not only to the dispatch destination server R2, the customer server R3, and the help source server R4 but also to a large number of relay servers 1. In FIG. 7, among the relay servers 1, customer servers are represented as relay servers 3, 31, 32, 33, and 34, and dispatch destination servers are represented as relay servers 2, 4, 5, and 6.

  In the table of FIG. 7, customer servers are described in the target column. On the other hand, the destination column describes the dispatch destination server. In this table, a dispatch destination server permitted to communicate with a certain customer server is described in a form associated with the customer server. For example, the relay server 3 permits communication from the relay servers 2, 4, and 6.

  For example, when there is a connection request from the dispatch destination server R2, the control unit 503 creates an access permission list based on information registered in the access permission information database 513, and transmits the access permission list to the dispatch destination server R2. . This access permission list is a list indicating the relay servers 1 that are permitted to communicate from the dispatch destination server R2.

  Note that the control unit 503 may transmit information registered in the access permission information database 513 to the dispatch destination server R2 without creating an access permission list. The dispatch destination server R2 can grasp customer servers with which it can communicate by performing appropriate processing on this information.

  The communication management information database (communication management information storage unit) 515 is a database that manages connection times and connection statuses between customer servers and dispatch destination servers.

  The communication management information database 515 will be specifically described with reference to FIG. FIG. 8 is a table showing the contents of the communication management information database 515. In the table of FIG. 8, each row indicates a media session established between the relay servers 1. In the active column, the relay server 1 on the side that requested access is described, and in the passive column, the relay server 1 on the side that requested access is described. Further, the start time of the media session is described in the start-time column, and the end time of the media session is described in the end-time column. When the media session is ongoing, “connecting” is recorded in the end-time column. Further, when the remote maintenance service escalation is performed, the dispatch destination server that has inherited the remote maintenance is described in the escalation column. As described above, the communication management information database 515 includes communication management information in which information for specifying the relay server 1 that has established the media session and the connection status (start time, end time, etc.) of the media session are associated with each other. It is recorded.

  The dispatch destination server R2, the customer destination server R3, and the help source server R4 include a LAN interface, a WAN interface, and a control unit. The configuration of the dispatch destination server R2, the customer server R3, and the help source server R4 is almost equivalent to the configuration in which the access permission information database 513 and the communication management information database 515 are omitted from the configuration of the call center server R1 shown in FIG. The description of the configuration of each part is omitted.

  Next, packet routing control in the relay communication system of this embodiment will be described. In the present embodiment, the client terminals 5 belonging to the remote LAN can communicate with each other without being aware of the WAN, so that packet routing processing can be performed in the application layer. . Hereinafter, a description will be given with reference to FIG. In the following description, in order to distinguish each client terminal 5, there is a case where an alphabet is added to the end of the code and displayed as a client terminal 5a, a client terminal 5b,.

  In the following description, it is assumed that the first service person dispatched service person remotely maintains the client terminal 5 of the customer factory, and the case where the packet is routed between the dispatch destination LAN 92 and the customer LAN 93 will be described. To do. In the following description regarding routing, it is assumed that a media session has already been established between the dispatch destination server R2 and the customer server R3. Processing for establishing a media session between the dispatch destination server R2 and the customer server R3 will be described later.

  In the relay communication system of the present embodiment, private IP addresses are allocated to the LANs 91 to 94 connected to each other via the WAN. Each private address is managed so as to be uniquely determined in the relay communication system. As an example, as shown in FIG. 9, it is assumed that the address of the destination LAN 92 is “172.16.1.0/24” and the address of the customer LAN 93 is “172.30.2.0/24”. I will explain.

  In the relay communication system according to the present embodiment, in order to realize packet routing in the application layer, at least one relay server 1 or client terminal 5 that can function as a routing device is prepared in the LAN to be routed. Yes. For example, in the case of this embodiment, it is assumed that the dispatch destination server R2 can function as a routing device in the dispatch destination LAN 92 and the client terminal 5d can function as a routing device in the customer LAN 93, respectively.

  In the relay communication system of this embodiment, when routing a packet, first, a search for a routable LAN is performed. Specifically, a routable LAN search command (hereinafter simply referred to as a LAN search command) is transmitted from any client terminal 5 to the relay server 1. In the following description, it is assumed that the client terminal 5b has transmitted a routable LAN search command to the dispatch destination server R2.

  Here, the “routable LAN” is a LAN including the relay server 1 or the client terminal 5 as a routing device. In FIG. 9, the dispatch destination LAN 92 and the customer LAN 93 are described as one, but actually, a plurality of LANs can be connected to each relay server 1, and each LAN is not necessarily routed. It is not always possible. Therefore, it is necessary to search for a routable LAN in this way.

  The dispatch destination server R2 that has received the LAN search command transfers the LAN search command to other relay servers 1 (call center server R1, customer server R3, etc.) constituting the relay group by referring to the relay group information. To do. Then, each relay server 1 (call center server R1, dispatch destination server R2, customer server R3, etc.) that has received the LAN search command communicates with each client terminal 5 registered in the client terminal information database 511. It is checked whether or not there is a client terminal 5 that can function as a routing device in the connected LAN. When the client terminal 5 having a function as a routing device is found, the LAN including the client terminal 5 is a routable LAN. Even when the relay server 1 itself can function as a routing device, the LAN including the relay server 1 is a routable LAN. In such a case, the relay server 1 generates LAN search response information that associates the fact that the LAN is a routable LAN and the private IP address of the LAN.

  Subsequently, the call center server R1, customer server R3, etc. transmit the generated LAN search response information to the dispatch destination server R2. The dispatch destination server R2 generates combined LAN search response information obtained by combining the LAN search response information generated by itself and the LAN search response information received from each relay server 1. The dispatch destination server R2 transfers the combined LAN search response information to the client terminal 5b. The client terminal 5b generates and stores LAN search result information based on the combined LAN search response information.

  An example of LAN search result information stored in the client terminal 5b is shown in FIG. In the LAN search result information, a child element network tag having a routing_network tag as a parent element is described. Each network tag describes private IP address information (“addr”) of a routable LAN. In this way, the private IP address of the LAN that can be routed in the relay communication system can be specified in the client terminal that is the transmission source of the LAN search command. For example, in this embodiment, as shown in FIG. 10, the destination LAN 92 (addr = “172.16.1.0/24”) and the customer LAN 93 (addr = “172.30.2.0/24”) Is identified as a routable LAN.

  Next, in the client terminal 5b that identifies the routable LAN, a routing route search (specifically, a routing point) is performed. The client terminal 5b specifies a routing target LAN from among routable LANs, and transmits a routing route search command (hereinafter simply referred to as a route search command) to the dispatch destination server R2. Hereinafter, a case where the dispatch destination LAN 92 and the customer LAN 93 are designated as the routing target LAN will be described.

  The dispatch destination server R2 that has received the route search command transfers the route search command to other relay servers 1 (call center server R1, customer server R3, etc.) that constitute the relay group by referring to the relay group information. To do.

  Each relay server 1 (call center server R1, dispatch destination server R2, customer server R3, etc.) that has received the route search command communicates with each client terminal 5 registered in the client terminal information database 511, thereby It is checked whether or not there is a client terminal 5 that can function as a routing device for a LAN designated as a routing target LAN.

  For example, in the case of this embodiment, the client terminal 5d can function as a routing device for a LAN (customer LAN 93) designated as a routing target LAN. In this way, the client terminal 5d that can function as a routing device for the routing target LAN can function as a routing point for routing packets between designated LANs (between the dispatch destination LAN 92 and the customer LAN 93). When a client terminal 5d that can function as a routing point is found, the customer server R3 generates route search response information that associates the private IP address of the customer LAN 93 with the identification information of the client terminal 5d.

  On the other hand, when the relay server 1 itself can function as a LAN routing device designated as a routing target LAN, the relay server 1 can function as a routing point. For example, in the present embodiment, the dispatch destination server R2 can function as a routing device for a LAN designated as a routing target LAN (dispatch destination LAN 92). In such a case, the dispatch destination server R2 generates route search response information in which the private IP address of the dispatch destination LAN 92 is associated with its own identification information.

  Subsequently, the customer server R3 transmits the generated route search response information to the dispatch destination server R2. The dispatch destination server R2 generates combined route search response information obtained by combining the route search response information received from the customer server R3 and the route search response information generated by itself. The dispatch destination server R2 transfers the combined route search response information to the client terminal 5b. The client terminal 5b generates and stores route search result information based on the combined route search response information.

  An example of route search result information stored in the client terminal 5b is shown in FIG. In the route search result information, a network tag of a child element having a routing_network tag as a parent element is described. In each network tag, private IP address information (“addr”) of a routable LAN and identification information (“router”) of a device that can function as a routing point are described in association with each other. In this way, a search for a routing path between LANs designated as routing target LANs (that is, specification of a routing point) can be realized.

  Next, a routing session is established. The routing session is a media session used for packet routing control in the relay communication system of the present embodiment.

  In order to establish a routing session, the client terminal 5b transmits information specifying a routing point used in the routing session to the dispatch destination server R2. In the dispatch destination server R2, routing group information is generated based on the route search result information. The routing group information is routing setting information for executing routing control using the relay communication system, and is stored in the routing group information database 522.

  An example of the routing group information stored in the routing group information database 522 is shown in FIG. In the routing group information, the network tag describes the local IP address of the routing target LAN and the identification information of the device used as the routing point in association with each other. In the session tag of the child element whose parent element is the routing_session tag, the start point (“start”) and the end point (“end”) of the routing session are described.

  Subsequently, the dispatch destination server R2 transfers the routing group information to the client terminal 5d that is the next routing point. Thereby, the information regarding the routing path | route between routing object LAN is shared in each routing point.

  After each routing point receives the routing group information, a routing session including a plurality of media sessions is established between the routing points. Specifically, a media session is established between the customer server R3 and the client terminal 5d. As described above, a media session has already been established between the dispatch destination server R2 and the customer server R3. The two media sessions constitute a routing session that connects the routing points (the dispatch destination server R2 and the client terminal 5d).

  Next, a case where a packet is transmitted from the terminal 5a in the dispatch destination LAN 92 to the client terminal 5f in the customer LAN 93 via a routing session will be described. In this case, the client terminal 5a creates a packet designating the private IP address (1722.30.2) of the client terminal 5f. Subsequently, the client terminal 5a transfers the packet to the dispatch destination server R2 that is a routing point of the LAN (the dispatch destination LAN 92) to which the client terminal 5a itself belongs.

  When receiving a packet to be routed, the dispatch destination server R2 as a routing point specifies a LAN to which the packet is to be delivered based on the destination private IP address (172.23.2.3). In this explanation, the destination LAN of the packet is the customer LAN 93 (the private IP address is 172.30.2.0/24). Next, the dispatch destination server R2 determines whether or not a valid routing session is established with the customer LAN 93 by referring to the routing group information. For example, in the example currently being described, it can be seen that a routing session has already been established with the customer LAN 93 by referring to the routing group information. Therefore, the packet may be transmitted using the routing session. It will be. If a routing session is not established here, an error occurs because transmission of a packet through the routing session is impossible.

  After identifying the routing session used for packet transmission, the dispatch destination server R2 as a routing point sends out the packet received from the client terminal 5a via the routing session. Thereby, the packet is received by the client terminal 5d which is the next routing point.

  The client terminal 5d, which is the next routing point, transfers the packet to the private IP address (1722.30.2) designated as the destination. Thereby, the packet is delivered to the client terminal 5f. Similarly, in the reverse communication (when a packet is transmitted from the client terminal 5f to the client terminal 5a), the packet can be routed through the routing session.

  The routing-related processing described above, that is, search for a routable LAN, search for a routing route, and the like are performed in the application layer. 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 WAN, and routing routes and the like can be determined according to the configuration of the relay communication system. Can be constructed flexibly. It should be noted that, in the case of performing single transmission / reception of information without establishing a routing session, it is needless to say that packets may be transmitted / received by a normal method without performing the above routing.

  In the present embodiment, the service person dispatched to the service person can perform remote maintenance of the client terminal 5 at the customer factory via the routing session described above. By the way, the routing session established as described above includes a media session between the relay servers 1. For example, in the above example, the routing session for transmitting and receiving packets between the client terminal 5a and the client terminal 5f includes a media session established between the dispatch destination server R2 and the customer server R3. ing. Therefore, it can be said that the service person performs remote maintenance via a media session established between the dispatch destination server R2 and the customer server R3. In the following explanation, even if a service person performs remote maintenance, explanation of the entire routing session is omitted, and only the part of the media session established between the dispatch destination server and the customer server is shown. May explain.

  As described above, when the media session is established between the dispatch destination server R2 and the customer server R3, the remote maintenance work such as confirmation of operation status and software update is performed on the client terminal 5 of the customer server R3. It can be performed. In addition, when a problem occurs in the client terminal 5, a recovery operation such as applying a recovery application can be performed.

  Next, the flow of processing when performing remote maintenance using the relay communication system of the present embodiment will be described with reference to the sequence diagrams of FIGS.

  When the first service person dispatched service person performs remote maintenance such as remote maintenance, the client terminal 5 is operated and an access permission list request for the call center server R1 as a transmission destination is made via the dispatch destination server R2. Transmit (sequence number 1).

  As described above, in this embodiment, a request or the like may be transmitted from the client terminal 5 via each relay server 1, but in the following description, a specific description of processing for operating the client terminal 5 is omitted. There are things to do.

  In this access permission list request, the account of the call center server R1 as the transmission destination is specified. The external server 2 acquires the global IP address of the call center server R1 by referring to the relay server account information database 203, and relays the request from the dispatch destination server R2 to the call center server R1.

  As described above, communication between each relay server 1 of the present embodiment is performed via the external server 2, and the same applies to the following. Therefore, in the following description, a specific description of communication processing via the external server 2 may be omitted.

  The call center server R1 that has received the access permission list request creates an access permission list indicating the relay servers that the dispatch destination server R2 can access based on the access permission information database 513. Then, the call center server R1 transmits this access permission list to the dispatch destination server R2.

  Then, the service person selects a customer server with which the service person should communicate based on the access permission list. In the present embodiment, it is assumed that the customer server R3 is selected as the connection destination customer server.

  However, as described above, the customer server R3 normally does not accept communications from other than the call center server R1. In order to start this communication, it is necessary to notify the access source (dispatch destination server R2) from the call center server R1 to the customer server R3. Therefore, the service person transmits an access destination notification (Access method) to the call center server R1 via the dispatch destination server R2 (sequence number 2).

  The selection of the customer server and the notification of the access destination may be automatically performed by the dispatch destination server R2 or the client terminal 5 by a preset method.

  Upon receiving this notification, the call center server R1 transmits an access permission request (ACCESS_PERMIT method) to the destination server R2 to the customer server R3 (sequence number 2.1).

  The customer server R3 that has received this access permission request performs processing for accepting communication from the dispatch destination server R2, and returns an OK response to the call center server R1. After receiving the OK response from the customer server R3, the call center server R1 returns an OK response to the access permission request to the dispatch destination server R2.

  Upon receiving this OK response, the dispatch destination server R2 transmits a connection request (INVITE method) to the customer server R3 (sequence number 3). The dispatch destination server R2 that has received the OK response to this transmits a final response (ACK method) to INVITE to the customer server R3 (sequence number 4). Then, the customer server R3 transmits a MediaSession command to the dispatch destination server R2. By this command, a communication path (routing session, data communication session) is established between the dispatch destination server R2 and the customer server R3 (sequence number 5).

  When the communication path is established, the control unit of the destination server R2 notifies the call center server R1 of the establishment of the routing session (NOTIFY_ESTABLISHMENT method (connection status notification), sequence number 5.1). Therefore, it can be said that the control unit of the dispatch destination server R2 functions as a connection status notification unit. On the other hand, the control unit of the call center server R1 receives the routing session establishment notification. Therefore, it can be said that the control unit of the call center server R1 functions as a connection status notification receiving unit. Then, the call center server R1 records the information specifying the relay servers (the dispatch destination server R2 and the customer server R3) constituting the routing session in association with the start time of the routing session in the communication management information database 515. To do. Subsequently, the call center server R1 returns an OK response to the notification of establishment of the routing session to the dispatch destination server R2.

  Next, the processing from sequence number 6 to sequence number 17 will be described later, and the termination of the routing session (connection disconnection) will be described.

  When the remote maintenance work is completed, as shown in FIG. 16, the service person transmits a message to end the session (BYE method) to the customer server R3 (sequence number 18). In response to this, the customer server R3 returns an OK response and disconnects communication. When an OK response is returned, the control unit of the dispatch destination server R2 serving as the connection status notification unit notifies the call center server R1 that the connection with the customer server R3 has been completed (NOTIFY_TERMINATION method (connection status notification)), sequence Number 19). The control unit of the call center server R1 serving as the connection status notification receiving unit receives the routing session end notification.

  Then, the call center server R1 associates information for specifying the relay servers (the dispatch destination server R2 and the customer server R3) constituting the routing session with the time when the routing session is ended, and manages the communication management information database. In step 515, an OK response to the notification of the end of the routing session is returned to the dispatch destination server R2.

  Through the processing described above, when starting or ending the routing session between the dispatch destination server R2 and the customer server R3, a log (communication management information) is stored in the communication management information database 515 of the call center server R1. The In this way, the connection status between the plurality of relay servers 1 is configured to be managed centrally in the call center server R1. Therefore, it can be said that the call center server R1 is a relay server with a management function. On the other hand, relay servers other than the call center server R1 (the dispatch destination server R2, the customer server R3, and the help source server R4) do not have the communication management information database 515, and therefore do not have a management function. Therefore, it can be said that the dispatch destination server R2, the customer server R3, and the help source server R4 are managed relay servers to be managed by the call center server R1.

  Next, a configuration for performing escalation of the remote maintenance service in the present embodiment will be described. In the following description, a service person who newly participates in remote maintenance through escalation may be particularly referred to as a “helper”.

  As described above, when remote maintenance is performed using a conventional communication system, there are few requests for escalation from a helper. On the other hand, the relay communication system of this embodiment is configured as follows so that the helper can actively escalate.

  In the following description, a serviceman belonging to the first serviceman dispatch destination performs remote maintenance of the client terminal 5 at the customer factory, and a serviceman belonging to the second serviceman dispatch destination is The explanation is based on the situation of participating as a helper. In the following, processing after a routing session is established between the dispatch destination server R2 and the customer server R3 with the sequence number 5 will be described.

  Escalation in remote maintenance means that a helper newly participates in a remote maintenance service that has already been performed. Therefore, when the helper actively tries to escalate, it is necessary for the helper to know which customer is receiving what remote maintenance service. Therefore, when actively escalating as a helper, the service person dispatched as the second service person operates the client terminal 5 to transmit a request for communication management information to the help source server R4. Upon receiving the communication management information request from the client terminal 5, the control unit of the help source server R4 transmits a communication management information request (REQUEST_CONDITION) with the call center server R1 as the transmission destination (sequence number 6). Therefore, it can be said that the control unit of the help source server R4 functions as a communication management information request unit.

  The control unit of the call center server R1 that has received a request for communication management information from the help source server R4 refers to the access permission information database 513 and the communication management information database 515, and performs communication management related to the customer server that can be accessed by the help source server R4. Reply information. For example, when the access permission information database 513 having the contents shown in FIG. 7 is referred to, it can be seen that the help source server (relay server 4) is permitted to access the relay servers 3, 32, and 33. Therefore, the control unit of the call center server R1 extracts the communication management information related to the relay servers 3, 32, and 33 from the communication management information recorded in the communication management information database 515, and transmits it to the help source server R4. Therefore, it can be said that the control unit of the call center server R1 functions as a communication management information transmission unit.

  As described above, the help source server R4 obtains communication management information related to the customer server (customer server to which the helper can provide the remote maintenance service) accessible from the help source server R4 by simply communicating with the call center server R1. can do. This is made possible by centrally managing the access permission information and the communication management information in the call center server R1. In the above configuration, communication management information related to a customer server that is not permitted to access from the help source server R4 (customer server for which the helper is not in charge of remote maintenance) is not transmitted to the help source server R4. Therefore, it is preferable also from a viewpoint of security.

  After receiving the communication management information from the call center server R1, the help source server R4 transfers the communication management information to the client terminal 5 that is directly operated by the helper. After receiving the communication management information, the client terminal 5 directly operated by the helper displays the content of the communication management information on the display. The helper confirms the contents of the communication management information displayed on the display, and identifies the customer factory where the remote maintenance service is currently being performed and the service provider dispatch destination that provides the remote maintenance service. . Specifically, when “connecting” is stored in the end-time field of the communication management information, between the destination server described in the active field and the customer server described in the passive field. It can be seen that a routing session has been established (ie, remote maintenance is being performed). For example, based on the communication management information as shown in the bottom row of FIG. 8, it can be seen that remote maintenance is performed between relay server 2 (dispatch destination server R2) and relay server 3 (customer server R3).

  When the helper finds a customer server and a dispatch destination server that are performing remote maintenance in this way, the helper determines whether or not escalation is necessary for the remote maintenance. Then, the current status is inquired using message communication (message session) (sequence number 7). Note that this message communication is a simple communication method (so-called instant message) that can communicate even with a party whose session has not been established by the INVITE method. Suitable for communication in real time. However, the communication that can be performed by the message communication is not limited to the text chat, but may be a video chat, for example.

  The service person who has received an inquiry about the current situation from the helper through message communication (for example, text chat) returns the progress of the current maintenance work to the helper using the same message communication. The helper examines after receiving a report on the current situation from a service person who is performing remote maintenance, and determines whether or not escalation is necessary. For example, when it is found by a reply by the message communication that a problem that cannot be dealt with by a service person currently performing maintenance work, the helper determines that escalation is necessary.

  When the helper determines that escalation is necessary, the helper operates the client terminal 5 to transmit an escalation request (that is, a session establishment request to the dispatch destination server R2 and the customer server R3) to the help source server R4. Then, the control unit of the help source server R4 transmits an escalation request (REQUEST_ESCALATION) to the call center server R1 (sequence number 8). Therefore, it can be said that the control unit of the help source server R4 functions as a session establishment request unit.

  When the escalation request from the help source server R4 is received, the control unit of the call center server R1 has received an escalation request from the help source server R4 to the dispatch destination server R2 and the customer server R3 (that is, the help source). That there is a session establishment request from the server R4) (sequence numbers 8.1 and 8.2). Therefore, it can be said that the control unit of the call center server R1 functions as a session establishment request source notification unit.

  Upon receiving notification of the escalation request source from the call center server R1, the dispatch destination server R2 and the customer server R3 perform processing for accepting communication from the help source server R4, and return an OK response to the call center server R1. After receiving the OK response from the dispatch destination server R2 and the customer server R3, the call center server R1 returns an OK response to the escalation request to the help source server R4.

  The help source server R4 that has received the OK response to the escalation request establishes a routing session between the dispatch destination server R2 and the customer server R3 (sequence numbers 9 to 14.1). Since the establishment of the routing session has already been described, the description thereof is omitted here. As described above, the help source server R4 that makes an escalation request can shift from message communication (inquiry about the status of remote maintenance work) regarding communication management information to a routing session (start of escalation).

  By establishing the routing session used for escalation, the helper at the second serviceman dispatch destination can perform remote maintenance of the client terminal 5 at the customer factory through the routing session. The helper can also remotely operate the client terminal 5 being used by the service person dispatched to the first service person who has been performing remote maintenance. Thereby, the helper can back up the remote maintenance work by the service person dispatched to the first service person. As in this case, the helper may not participate in the remote maintenance of the client terminal 5 at the customer factory, but may participate in the remote maintenance as a supporter for the service person who is performing the maintenance work.

  When the escalation ends, the help source server R4 sends an end notification to the dispatch destination server R2 and the customer server R3 (sequence numbers 15 and 16), and reports the end of the escalation to the call center server R1 (sequence number). 17) End the session.

  As described above, in this embodiment, the call center server R1 as a managed relay server functions as an access permission information database 513, a communication management information database 515, a connection status notification receiving unit, and a communication management information transmitting unit. A control unit. The access permission information database 513 stores information stored in association with the relay servers 1 that are permitted to access each other among the plurality of relay servers 1. When the data communication session is established between the relay servers 1, the control unit as the connection status notification receiving unit configures the data communication session with a connection status notification that notifies at least the start and end of the data communication session. Received from the relay server 1. The communication management information database 515 stores communication management information in which the contents of the connection status notification received by the control unit are stored in association with the relay server 1 constituting the data communication session. When receiving a request for communication management information from a certain relay server 1, the control unit as the communication management information transmitting unit receives communication management information related to the relay server 1 that permits access to the relay server 1 that is the source of the communication management information. Is transmitted to the relay server 1 of the communication management information request source.

  Thereby, the access permission information and the communication management information can be centrally managed by the relay server with management function (call center server R1) without being distributed to the plurality of relay servers 1. Thereby, the help source server R4 can acquire the communication management information related to the customer server R3 permitted to access from the help source server simply by communicating with the call center server R1. Accordingly, the help source server R4 that has acquired the communication management information can grasp which dispatch destination server and which customer server are communicating.

  In the present embodiment, the control unit of the call center server can also function as a session establishment request source notification unit. The control unit as the session establishment request source notifying unit is a case where a routing session is established between the dispatch destination server R2 and the customer server R3, and the help source server R4 is connected to the dispatch destination server R2 and the customer destination. When an escalation is requested to the server R3, an escalation request from the help source server R4 is received, and the help source server R4 that is the escalation request source is notified to the dispatch destination server R2 and the customer server R3.

  Thereby, it is possible to notify in advance that the help source server R4 is going to connect to the dispatch destination server R2 and the customer server R3 in which the routing session is established. Therefore, the dispatch destination server R2 and the customer server R3 constituting the previously established routing session can appropriately process a new connection request.

  In the present embodiment, R2 and R4 as dispatch destination servers include a control unit that functions as a connection status notification unit, a communication management information request unit, and a session establishment request unit. When establishing a data communication session with another relay server 1, the control unit as the connection status notification unit sends a connection status notification for notifying at least the start and end of the data communication session to the call center server R1. And the communication management information is recorded in the call center server R1. The control unit serving as the communication management information request unit requests the communication management information from the call center server R1. After receiving the communication management information from the call center server R1, the control unit as a session establishment request unit sends a session establishment request for any customer server or dispatch destination server R2 recorded in the communication management information. Can be transmitted to the call center server R1.

  That is, since the communication management information is centrally managed in the call center server R1, the help source server R4 as the dispatch destination server stores the communication management information related to the customer server R3 permitted to access from the help source server R4. It can be acquired simply by communicating with the call center server R1. Then, after receiving the communication management information, the help source server R4 makes a session establishment request (escalation request) to the customer server R3 and the dispatch destination server R2 described in the communication management information. Therefore, the helper can select the customer server R3 and the dispatch destination server R2 to be escalated based on the contents of the communication management information.

  Further, the help source server R4 of the present embodiment, when the dispatch destination server R2 and the customer server R3 that have established the routing session are specified based on the communication management information, the dispatch destination server R2 and the customer server Before performing escalation to R3, it is possible to perform message communication with the dispatch destination server R2.

  As a result, the dispatch server R2 that performs remote maintenance of the customer server R3 is inquired about the progress of the maintenance work by message communication, and the help for the maintenance work is required based on the response to the inquiry. It is possible to actively participate in remote maintenance work, such as escalation when help is needed after determining whether or not.

  In addition, the relay communication system of the present embodiment includes a call center server R1 as a relay server with a management function, a dispatch destination server R2, a customer server R3, and a help source server R4 to be managed by the call center server R1. .

  In this relay communication system, access permission information and communication management information can be centrally managed by a call center server without being distributed to a plurality of relay servers 1. Thereby, the help source server R4 can acquire the communication management information related to the customer server R3 permitted to access from the help source server R4 only by communicating with the call center server R1.

  Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

  In the above description, the help source server R4 that performs escalation has established a routing session between both the dispatch destination server R2 and the customer server R3, but only one of them may be used. Further, when an escalation request is received from the help source server R4 (sequence number 8), the call center server R1 notifies the connection to both the dispatch destination server R2 and the customer server R3. When connecting to only one side, it is only necessary to notify only the connection destination.

  The client terminal information, relay server information, relay group information, routing group information, etc. have been described as XML format data when described with reference to the drawings. However, the format for storing the information is not limited to this. Each information can be stored in an appropriate format.

R1 call center server (relay server with management function)
R2 dispatch destination server (managed relay server)
R3 Customer server (managed relay server)
R4 help source server (managed relay server)
503 Control unit 513 Access permission information database (access permission information storage unit)
515 Communication management information database (communication management information storage)

Claims (5)

For each managed relay server, an access permission information storage unit that stores access permission information that stores other managed relay servers that are permitted to access the managed relay server ;
When a data communication session is established between the managed relay servers, at least a connection status notification for notifying the start and end of the data communication session is received from the managed relay server constituting the data communication session A notification receiver;
A communication management information storage unit for storing communication management information stored in association with the contents of the connection status notification received by the connection status notification receiving unit and the managed relay server constituting the data communication session;
Upon receiving a request for communication management information from a managed relay server, the communication management information related to the managed relay server that is permitted to access the managed relay server that is the source of the communication management information request is extracted, and the communication management A communication management information transmission unit for transmitting to the managed relay server of the information request source;
A relay server with a management function, characterized by comprising: A relay server with a management function according to claim 1,
Which is the case where a first data communication session is established between managed relay servers, and a managed relay server that does not constitute the first data communication session constitutes the first data communication session When a second data communication session is to be established with the managed relay server as a partner, a session establishment request is received from the managed relay server that is the establishment request source of the second data communication session, and the first A session establishment request source notifying unit for notifying at least one of the managed relay servers constituting the data communication session of the managed relay server that is the establishment request source of the second data communication session; A relay server with a management function. When a data communication session is established with another relay server, at least a connection status notification for notifying the start and end of the data communication session is sent to the relay server with a management function for managing communication between the relay servers. A connection status notification unit for transmitting and recording the communication management information in the relay server with the management function,
A communication management information requesting unit for requesting the communication management information to the relay server with management function;
After the communication management information related to the managed relay server that allows communication with its own, said management functions with the relay server to the receiver, session one of the relay server, wherein recorded in the communication management information with the partner A session establishment request unit capable of transmitting an establishment request to the relay server with management function;
A relay server comprising: The relay server according to claim 3,
When a relay server that has established a first data communication session with another relay server is identified based on the communication management information, the first data communication session is established with the established relay server. 2. A relay server capable of performing message communication with a relay server that has established the first data communication session before establishing the two data communication sessions. For each managed relay server, an access permission information storage unit that stores access permission information that stores other managed relay servers that are permitted to access the managed relay server ;
When a data communication session is established between the managed relay servers, at least a connection status notification for notifying the start and end of the data communication session is received from the managed relay server constituting the data communication session A notification receiver;
A communication management information storage unit for storing communication management information stored in association with the contents of the connection status notification received by the connection status notification receiving unit and the managed relay server constituting the data communication session;
Upon receiving a request for communication management information from a managed relay server, the communication management information related to the managed relay server that is permitted to access the managed relay server that is the source of the communication management information request is extracted, and the communication management A communication management information transmission unit for transmitting to the managed relay server of the information request source;
A relay server with management function with
A plurality of managed relay servers to be managed by the relay server with management function;
A relay communication system comprising:

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