JP2011076532A - Data distribution system, server, data distribution method, computer program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data distribution system for enabling a server to efficiently transmit data to a client without complicating data transmission control even if the system is enlarged, and to provide a server, a data distribution method, a computer program and a recording medium. <P>SOLUTION: Among a plurality of clients 11 to 19, one and the other clients connected to the same communication network are specified as a transfer source client and transfer destination client, respectively. Since the transfer source client receiving data from a server 1 transfers the data to the transfer destination clients, the system transmits and transfers the data with simple control even if the system for distributing the data is enlarged. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a data distribution system, a data distribution method, a computer program, a recording medium storing the computer program, and a plurality of connected clients, in which data transmitted from a server is transferred between the plurality of clients connected to the server. The present invention relates to a server for transferring data in between.

  In recent years, information resources such as applications and databases shared by employees in corporations are enormous, and it is necessary to prepare an environment where many employees can use information resources efficiently. Therefore, a company connects a large number of terminals (clients) used by employees to a server that centrally manages information resources, sends a request from each client to the server, and builds a client / server system to which the server responds. In many cases, the information resources are used efficiently.

  If there is shared data in the client / server system, the shared data is managed by the server, and when the shared data is updated by any client, the updated data is transmitted to the server to update the shared data of the server. The update data is transmitted from the server to each unupdated client, and the shared data of each client may be updated.

  In this case, when there are a small number of clients, even if update data is sent from the server to each client, the load on the server does not become excessive, but when there are a large number of clients, the load on the server becomes excessive, Efficient use of information resources may be hindered.

  Patent Document 1 discloses a data distribution system that reduces the load on the server. The data distribution system provides each client with divided data that is divided in advance by the server and data distribution information that includes the transmission destination of the divided data. The divided data is transmitted between the clients based on the data distribution information, and the data is completed at each client. Also, the data distribution system adjusts the number of divided data distributed from the server to each client according to the transmission / reception capability of the client, thereby reducing the burden on the server and harmonizing the efficient use of information resources. ing.

  Patent Document 2 discloses a network system in which a plurality of nodes are connected to a server. In the network system, the server designates the highest node, and each node transfers data from the highest node to a lower node. The route for transferring in order is determined. The node reduces the load on the server by sequentially transferring data from the highest node to the lowest node according to the determined route. In addition, since data is transferred sequentially, unicast transfer is possible, and it is not necessary to use a router that supports multicast, and it is not reliable UDP (User Datagram Protocol), but highly reliable TCP (Transmission Data can be transferred by Control Protocol.

JP 2009-9297 A JP 2009-26107 A

  However, the data distribution system described in Patent Document 1 needs to perform a data division process, a process for controlling the number of pieces of divided data to be transmitted to a client according to transmission / reception capability, a process for transferring divided data between clients, and the like. Therefore, when a data distribution request is transmitted from a large number of clients to the server, the processing in the data distribution system becomes complicated and it is difficult to cope with a large-scale system.

  The network system described in Patent Document 2 also needs to perform processing for designating the highest node, processing for determining a route for transferring data, processing for sequentially transferring data according to the determined route, and the like. The processing in the system is complicated, and it cannot be said that it is sufficient to handle a large-scale system. There is also a problem that it takes a long time to transmit data to the lowest node.

  The present invention has been made in view of such circumstances, and the object of the present invention is to efficiently transfer data from the server to the client without complicating data transmission control even when the system is scaled up. An object is to provide a data distribution system, a server, a data distribution method, a computer program, and a recording medium that can be transmitted.

  In the data distribution system according to the present invention, a server in which a plurality of clients are connected via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients. In the system, the server obtains identification information for identifying a communication network to which the client is connected, and means for distinguishing the client for each communication network based on the identification information obtained by the means; Means for designating a transfer source client for transferring data transmitted from the server and a transfer destination client for receiving the transferred data from a plurality of clients connected to the same communication network distinguished by the means; It is characterized by providing.

  In the data distribution system according to the present invention, a server in which a plurality of clients are connected via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients. The system includes means for measuring a communication speed between the plurality of clients, and the server is measured with means for designating a transfer source client for transferring data transmitted from the server from the plurality of clients. And a means for designating a transfer destination client having the fastest communication speed with the transfer source client based on the communication speed.

  In the data distribution system according to the present invention, a server in which a plurality of clients are connected via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients. The system comprises means for measuring a communication speed between the plurality of clients, the server determining whether or not the measured communication speed is equal to or higher than a preset threshold, and the communication by the means. When it is determined that the speed is equal to or higher than the threshold value, the transfer source client that transfers the data transmitted from the server to the two clients that are the targets of the communication speed and the data transferred from the transfer source client And means for designating a transfer destination client to receive.

  In the data distribution system according to the present invention, a server in which a plurality of clients are connected via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients. The system comprises means for measuring a first communication speed between the server and one client, and means for measuring a second communication speed between the one client and another client, the server comprising: When the measured first communication speed is slower than the second communication speed, the other client is designated as a transfer source client for transferring data transmitted from the server, and the one client is designated as the transfer source. Means is provided for designating a transfer destination client that receives data transferred from the client.

  In the data distribution system according to the present invention, the server includes means for transmitting information indicating the designated transfer destination client to the transfer source client before transmitting data to the transfer source client. When the transfer source client receives information indicating the above, a transmission / reception enabled state in which data can be transmitted and received between the transfer source client and the transfer destination client is established.

  The data distribution system according to the present invention is characterized in that the transmission / reception enabled state is established one-to-one between the transfer source client and the transfer destination client.

  In the data distribution system according to the present invention, the server is configured to determine whether or not there are a plurality of the clients that are not established in the transmission / reception enabled state; And a means for designating a client for which the transmission / reception enabled state is to be established among the clients that are judged to be present, and between the clients designated by the means. The transmission / reception enabled state can be established.

  In the data distribution system according to the present invention, the server receives the data at the transfer source client by means for determining whether or not the transfer source client can receive the data. Means for forcibly terminating the transmission / reception enabled state to a transfer destination client that has established the transmission / reception enabled state with a transfer source client that is unable to receive data when it is determined that the transmission / reception is impossible. It is characterized by providing.

  The data distribution system according to the present invention determines whether the transfer source client (or the transfer destination client) can receive data at the transfer destination client (or the transfer source client). And the transfer destination client (or the transfer source client) that cannot receive the data when it is determined that the data cannot be received by the transfer destination client (or the transfer source client). And means for forcibly terminating the transmission / reception enabled state established with the transfer destination client (or the transfer source client) incapable of receiving data. It is characterized by providing.

  In the data distribution system according to the present invention, in order for the server to transfer data distributed from the server between the clients, means for storing information indicating a correspondence relationship between the clients; and Or a means for changing information indicating a correspondence relationship between the clients when the connection between the server and the client is disconnected.

  In the server according to the present invention, when a plurality of clients are connected via a communication network and the server that distributes data to at least one client receives a connection request from the client, the client connects. Means for acquiring identification information for identifying a communication network, means for distinguishing the client for each communication network based on the identification information acquired by the means, and connection to the same communication network distinguished by the means A transfer source client that transfers data transmitted from the server and a transfer destination client that receives the transferred data from a plurality of clients.

  In the server according to the present invention, a plurality of clients are connected via a communication network, and a server that distributes data to at least one client transfers data transmitted from the server from among the plurality of clients. Means for designating a transfer source client, and designating a transfer destination client having the fastest communication speed from the transfer source client based on communication speeds between the plurality of clients.

  In the server according to the present invention, a plurality of clients are connected via a communication network, and in a server that distributes data to at least one client, a communication speed between the plurality of clients is equal to or higher than a preset threshold. A means for determining whether or not the communication speed is equal to or higher than the threshold value, and transfers the data transmitted from the server to both clients for which the communication speed is to be determined. A transfer source client, and a means for designating a transfer destination client that receives data transferred from the transfer source client.

  In the server according to the present invention, a plurality of clients are connected via a communication network, and in the server that distributes data to at least one client, the communication speed between the server and the one client is the one client. And the other client is designated as a transfer source client for transferring data transmitted from the server, and the one client is transferred from the transfer source client. Means for designating a transfer destination client that receives the received data.

  The data distribution method according to the present invention is a data distribution method for transferring data distributed from a server between a plurality of clients connected to the server via a communication network, wherein the server is connected to the client. Obtaining identification information for identifying a communication network; distinguishing the client for each communication network based on the identification information; and a plurality of clients connected to the same differentiated communication network; And a step of designating a transfer source client for transferring the data transmitted from the server and a transfer destination client for receiving the transferred data.

  The data distribution method according to the present invention includes a step of measuring a communication speed between the plurality of clients in a data distribution method for transferring data distributed from a server between the plurality of clients connected to the server, Specifying a transfer source client for transferring data transmitted from the server, and specifying a transfer destination client with the fastest communication speed with the transfer source client based on the measured communication speed And a step of performing.

  The data distribution method according to the present invention includes a step of measuring a communication speed between the plurality of clients in a data distribution method for transferring data distributed from a server between the plurality of clients connected to the server, Determining whether or not the communication speed set is equal to or higher than a preset threshold, and when it is determined that the communication speed is equal to or higher than the threshold, And a step of designating a transfer source client for transferring data transmitted from the server and a transfer destination client for receiving data transferred from the transfer source client.

  The data distribution method according to the present invention is a data distribution method for transferring data distributed from a server between a plurality of clients connected to the server, wherein the first communication speed between the server and one client is set. A step of measuring, a step of measuring a second communication speed between the one client and another client, and the other client when the measured first communication speed is slower than the second communication speed. Designating as a transfer source client for transferring data transmitted from the server, and designating the one client as a transfer destination client for receiving data transferred from the transfer source client. .

  When a plurality of clients are connected to a computer via a communication network, the computer program according to the present invention causes a computer to function as a server that distributes data to at least one client. Means for acquiring identification information for identifying a communication network to which the client is connected; means for distinguishing the client for each communication network based on the identification information acquired by the means; and the same communication network distinguished by the means It functions as means for designating a transfer source client that transfers data transmitted from the server and a transfer destination client that receives the transferred data from a plurality of clients connected to the server.

  When a plurality of clients are connected to a computer via a communication network, the computer program according to the present invention is a computer program that causes a computer to function as a server that distributes data to at least one client. Based on the means for designating the transfer source client for transferring the data transmitted from the server and the communication speed between the plurality of clients, the transfer destination client having the fastest communication speed from the transfer source client It is made to function as a means to specify.

  When a plurality of clients are connected to a computer via a communication network, the computer program according to the present invention causes a computer to function as a server that distributes data to at least one client. Means for determining whether or not the communication speed between a plurality of clients is equal to or higher than a preset threshold, and when the communication speed is determined to be equal to or higher than the threshold by the means, The both clients are made to function as means for designating a transfer source client for transferring data transmitted from the server and a transfer destination client for receiving data transferred from the transfer source client.

  When a plurality of clients are connected to a computer via a communication network, the computer program according to the present invention causes a computer to function as a server that distributes data to at least one client. When the communication speed between the server and the one client is faster than the communication speed between the one client and the other client, the transfer source that transfers the data transmitted from the server to the other client It is designated as a client, and the one client is made to function as means for designating as a transfer destination client that receives data transferred from the transfer source client.

  The recording medium according to the present invention records any one of the computer programs described above.

  In the present invention, among a plurality of clients connected to the same communication network, one client is designated as a transfer source client, and the other client is designated as a transfer destination client. Then, the transfer source client that has received the data from the server transfers the data to the transfer destination client. In addition, when identification information for identifying a communication network is stored and managed in the server, even if the configuration of the data distribution system is changed due to connection / disconnection between the client and the server, the transfer is performed according to the change in the system. The original client and the transfer destination client can be redesignated.

  In the present invention, a transfer source client is specified from among a plurality of clients connected to the server, and a client that can communicate with the transfer source client at the fastest communication speed is specified as a transfer destination client. In addition, when the communication speed between a plurality of clients connected to the server is stored and managed by the server, even if the configuration of the data distribution system is changed due to connection / disconnection between the client and the server, the change of the system The transfer source client and the transfer destination client can be designated again according to the above.

  In the present invention, when the communication speed between one client connected to the server and another client is equal to or higher than a preset threshold, both clients are designated as a transfer source client and a transfer destination client, respectively. When information indicating the transfer source client and the transfer destination client is stored in the server, communication between the new client and the existing client is possible even when the new client connects to the server and the configuration of the data distribution system is changed. The transfer source client and the transfer destination client can be redesignated by comparing the speed with the threshold value.

  In the present invention, when the communication speed between the server and one client is slower than the communication speed between the one client and another client, one client is designated as the transfer destination client and the other client is transferred. Specify the original client. In addition, when information indicating the transfer source client and the transfer destination client is stored and managed by the server, even if the configuration of the data distribution system is changed due to connection / disconnection between the client and the server, etc. The transfer source client and the transfer destination client can be redesignated.

  In the present invention, before the data is transmitted from the server to the transfer source client, information indicating the transfer destination client is transmitted to the transfer source client, and data can be transmitted / received between the transfer source client and the transfer destination client. Establish state (connection). Therefore, data transmitted from the server to the transfer source client is immediately transferred to the transfer destination client.

  In the present invention, since the above-described connection is established one-to-one between the transfer source client and the transfer destination client, the server designates half of the plurality of clients as the transfer source client, and the data Can be distributed to each transfer source client, so that the load on the server is reduced. In addition, data transmission / transfer control of the system is simplified as compared with the case where a one-to-many connection is established between a transfer source client and a transfer destination client.

  In the present invention, when the connection between the transfer source client and the transfer destination client is disconnected or the transfer source client or the transfer destination client leaves the system, there are a plurality of unestablished clients. A plurality of clients that should establish a connection are extracted from a plurality of clients that have not yet established a connection, and a connection is established between the extracted clients.

  In the present invention, when it is impossible for the transfer source client to receive data, the server forcibly causes the transfer destination client that has established a connection with the transfer source client to disconnect the connection. Therefore, the transfer source client that cannot receive data can be excluded from the data distribution system, and the data distribution system can be maintained.

  In the present invention, for example, when data cannot be received by the transfer destination client, the transfer source client transmits information indicating the transfer destination client that cannot receive data to the server, and transfers the data. The connection established with the destination client is forcibly disconnected. Therefore, the transfer destination client that cannot receive data can be excluded from the data distribution system, and the data distribution system can be maintained.

  In the present invention, information indicating the correspondence between clients is stored in the server. When the client connects to the server, that is, when the client enters the data distribution system, information indicating the client connected to the server is stored in the server, and when the client disconnects from the server, that is, the client has data When leaving the distribution system, the information indicating the disconnected client is deleted from the information stored in the server, and the information indicating the correspondence relationship is changed.

  In the present invention, among a plurality of clients connected to the same communication network, one client is designated as a transfer source client, and the other clients are designated as transfer destination clients. Then, the transfer source client that has received the data from the server transfers the data to the transfer destination client. Therefore, even if the system for distributing data becomes large, the system can transmit and transfer data with simple control, efficiently distribute data from the server to the transfer source client, and between the transfer source client and the transfer destination client. Can quickly transfer data without going through a router. Since the data is transferred without going through the router, it is transferred to the transfer destination client in a short time. In addition, when the identification information for identifying the communication network is stored and managed by the server, even if the configuration of the data distribution system is changed due to connection / disconnection between the client and the server, the transfer source client and the transfer destination client can be easily Can be re-specified.

  In the present invention, a transfer source client is specified from among a plurality of clients connected to the server, and a client that can communicate with the transfer source client at the fastest communication speed is specified as a transfer destination client. Therefore, even if the system for distributing data becomes large, the system can transmit and transfer data with simple control, efficiently distribute data from the server to each transfer source client, and transfer source client and transfer destination client Data can be transferred quickly between. Further, when the communication speed between a plurality of clients connected to the server is stored and managed by the server, even if the configuration of the data distribution system is changed due to connection / disconnection between the client and the server, the transfer source client and The destination client can be easily specified again.

  In the present invention, when the communication speed between one client connected to the server and another client is equal to or higher than a preset threshold value, both clients are designated as a transfer source client and a transfer destination client, respectively. Information indicating the transfer source client and the transfer destination client is stored in the server. Therefore, even if the system for distributing data becomes large, the system can transmit and transfer data with simple control, efficiently distribute data from the server to each transfer source client, and transfer source client and transfer destination client Data can be transferred quickly between. Also, even if a new client connects to the server and the system configuration is changed, it is possible to re-specify the transfer source client and transfer destination client only by comparing the communication speed between the new client and the existing client with the threshold value. It is possible to determine whether or not to transfer, and the transfer source client and transfer destination client can be easily specified again.

  In the present invention, when the communication speed between the server and one client is slower than the communication speed between the one client and another client, one client is designated as the transfer destination client, and the other client Is specified as the transfer source client. Therefore, even if the data distribution system becomes large-scale, the system can transmit and transfer data with simple control, efficiently distribute data from the server to each transfer source client, and between the transfer source client and the transfer destination client. Can transfer data quickly. In addition, when information indicating the transfer source client and transfer destination client is stored and managed by the server, the transfer source client and transfer destination client can be easily accessed even if the system configuration is changed due to connection / disconnection between the client and the server. Can be re-specified.

1 is a conceptual diagram schematically showing a data distribution system according to an embodiment. It is a block diagram which briefly shows the structure of a server. It is a block diagram which briefly shows the structure of a client. It is a conceptual diagram which shows an example of the communication path | route information table memorize | stored in the memory | storage part of the server. It is a flowchart explaining establishment of the connection with the server by the control part of a client. It is a flowchart explaining the connection process with the client by the control part of a server. It is a flowchart explaining the 1st Example of the selection process by the control part of a server. It is a flowchart explaining the grouping process by the control part of a server. It is a flowchart explaining the group priority process by the control part of a server. It is a flowchart explaining the threshold value process by the control part of a server. It is a flowchart explaining the calculation process of the communication speed by the control part of the client corresponding to the isolated number i or the isolated number j. It is a flowchart explaining the process in the control part of the other client which received the communication speed measurement request from one client. It is a flowchart explaining the 2nd Example of the selection process by the control part of a server. It is a flowchart explaining the fastest process by the control part of a server. It is a flowchart explaining the 3rd Example of the selection process by the control part of a server. It is a flowchart explaining the server client communication speed measurement process in the control part of a server. It is a flowchart explaining the communication route determination process between clients in the control part of a server. It is a flowchart explaining the connection establishment process by the control part of a client. It is a conceptual diagram which shows establishment of the connection between the transfer origin client and the transfer destination client. It is a flowchart explaining the update process by the control part of the transfer source client when shared data is updated in the transfer source client. It is a flowchart explaining the update process of the shared data by the control part of the transfer destination client when update data is received. It is a flowchart explaining the update process by the control part of a transfer destination client when shared data is updated in the transfer destination client. It is a flowchart explaining the update process by the control part of the transfer origin client when the transfer destination IP address and update data are received from the transfer destination client. It is a flowchart explaining the update process of the shared data by the control part of a server when update data is received. It is a flowchart explaining the update process of the shared data by the control part of the transfer origin client at the time of receiving update data from a server. It is a flowchart explaining the leaving process which the control part of a transfer origin client performs when the transfer origin client leaves a data delivery system. It is a flowchart explaining the process by the control part of a transfer destination client when the leaving data is received from the transfer source client. It is a flowchart explaining the process which cut | disconnects the connection with the transfer origin client by the control part of a server. FIG. 10 is a flowchart for explaining an exit process executed by the control unit of the transfer destination client when the transfer destination client leaves the data distribution system. FIG. It is a flowchart explaining the process which the control part of the transfer origin client when the leaving data is received from the transfer destination client is performed. It is a flowchart explaining the process which the control part of a server performs when the leaving data of the transfer destination client is received from the transfer source client. It is a flowchart explaining the leaving process from the data delivery system by the control part of an isolated client. It is a flowchart explaining the process which the control part of the server which received the leaving data from the isolated client performs. It is a flowchart explaining the process which the control part of a server performs when a new client is connected to a server after communication path information table creation. 10 is a flowchart for explaining failure countermeasure processing executed by a control unit of a transfer destination client when shared data is updated in the transfer destination client and a failure occurs in the transfer source client. 10 is a flowchart for explaining a deletion process executed by a control unit of a server when shared data is updated in a transfer destination client and a failure occurs in the transfer source client. 10 is a flowchart for explaining failure countermeasure processing executed by the control unit of the transfer source client when shared data is updated in the transfer source client and a transfer destination client has a failure. It is a flowchart explaining the deletion process which the control part of a server performs when shared data is updated in the transfer source client and a failure has occurred in the transfer destination client. It is a flowchart explaining the deletion process which the control part of a server performs, when the failure has generate | occur | produced in the transfer origin client which the server transmitted update data. It is a flowchart explaining the cutting process which the control part of a transfer destination client performs when the instruction | command which forcibly cuts the connection with the transfer origin client is received. 10 is a flowchart for explaining a deletion process executed by a control unit of a server when a failure has occurred in a transfer destination client to which update data has been transferred from a transfer source client. It is a flowchart explaining the cutting process which the control part of a transfer origin client performs when there is no response which shows having received update data from the transfer destination client.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating a data distribution system according to an embodiment. FIG. 1 is a conceptual diagram schematically showing a data distribution system.

  In the figure, reference numeral 1 denotes a server 1 that transmits and receives data, and the server 1 is connected to a network 50. A plurality of routers 21 to 25 are connected to the network 50, and two clients 11 and 12 are connected to the router 21 via a switch 31. A client 13 is connected to the router 22, and two clients 14 and 15 are connected to the router 23 via a switch 32. A client 16 is connected to the router 24, and clients 17 to 19 are connected to the router 25 via a switch 33. Communication between the server 1 and the clients 11 to 19 is performed based on IPv4 (Internet Protocol version 4). The communication between the server 1 and the clients 11 to 19 may be based on another communication protocol executed end-to-end, such as communication performed based on IPv6 (Internet Protocol version 6).

FIG. 2 is a block diagram schematically showing the configuration of the server.
The server 1 includes a control unit 1a that controls data communication, an operation unit 1b that receives user operations, a display unit 1c that displays information for the user, and an I / F (InterFace) unit 1d that is connected to the network 50. And a storage unit 1e for storing information. Each component of the server 1 is connected to each other via a common bus, and a control command is input to the control unit 1a from the operation unit 1b or the I / F unit 1d.

  The control unit 1a includes a CPU (Central Processing Unit) that performs calculation, a ROM (Read Only Memory) that stores a communication control program, a RAM (Randam Access Memory) that temporarily stores data, a timer, and the like. Based on a control program stored in the ROM, the CPU executes a calculation based on a control command or the like using the RAM as a work area, and outputs a calculation result to the display unit 1c, the storage unit 1e, and the I / F unit 1d. In the RAM, variables, thresholds, and the like described later are set at predetermined timing. The control unit 1a uses a timer to measure the communication speed between the clients 11 to 19 and the server 1, for example.

  The operation unit 1b receives a user operation and outputs a control command to the control unit 1a. The display unit 1c displays characters, figures, and the like based on commands from the control unit 1a. The storage unit 1e is a magnetic disk storage device such as an HDD (Hard Disc Drive), and the storage unit 1e has shared data shared with the clients 11 to 19 and a communication path for transferring data between the clients 11 to 19. The communication path information table shown is stored. The shared data and communication path information table are updated by a command from the control unit 1a. The storage unit 1e is not limited to a magnetic disk storage device, and may be configured by a semiconductor memory.

FIG. 3 is a block diagram schematically showing the configuration of the client.
The clients 11 to 19 include control units 11a to 19a that control data communication, operation units 11b to 19b that receive user operations, display units 11c to 19c that display information for the user, and routers 21 to 25 or I / F units 11d to 19d connected to the switches 31 to 33 and storage units 11e to 19e for storing information are provided. The constituent elements of the clients 11 to 19 are connected to each other via a common bus, and control commands are input to the control units 11a to 19a from the operation units 11b to 19b or the I / F units 11d to 19d.

  The control units 11a to 19a include a CPU that performs calculation, a ROM that stores a communication control program, a RAM that temporarily stores data, a timer, and the like. Based on a control program stored in the ROM, the CPU executes a calculation based on a control command or the like using the RAM as a work area, and displays the calculation results as display units 11c to 19c, storage units 11e to 19e, and an I / F unit 11d to Output to 19d. For example, the control units 11a to 19a use a timer to measure the communication speed between the clients 11 to 19 or the communication speed between the clients 11 to 19 and the server 1.

  The operation units 11b to 19b receive user operations and output control commands to the control units 11a to 19a. The display parts 11c-19c display a character, a figure, etc. based on the instruction | command from control part 11a-19a. The storage units 11e to 19e are magnetic disk storage devices such as HDDs, and the storage units 11e to 19e store shared data shared with the server 1. The shared data is updated by a command from the operation units 11b to 19b. The storage units 11e to 19e are not limited to the magnetic disk storage device, and may be configured by a semiconductor memory.

FIG. 4 is a conceptual diagram illustrating an example of a communication path information table stored in the storage unit of the server.
The communication path information table includes entry numbers (No.) of the clients 11 to 19, IP addresses of the clients 11 to 19, transfer destination IP addresses, group information, control information, and the like. The entry number is a number assigned to the clients 11 to 19 connected to the server 1. In this embodiment, the numbers 11 to 19 are assigned to the clients 11 to 19.

  The IP addresses are included in connection requests from the clients 11 to 19 to the server 1 and are recorded in the communication path information table when the clients 11 to 19 are connected to the server 1. In this embodiment, the IP addresses of the clients 11 to 19 correspond to the class C full address C class, and the 24 bits from the top of the IP address are the network address part. The IP address corresponds to the entry number. The transfer destination IP address corresponds to the IP address of the transfer source client when one client is the transfer source client that transfers data and the other client is the transfer destination client that receives the data transferred from the transfer source client. The IP address of the transfer destination client recorded in the communication path information table.

  The group information is information for identifying the subnetwork (communication network) to which the clients 11 to 19 are connected, and the same group information is given to each of the clients 11 to 19 connected to the same subnetwork. Is done. In the present embodiment, the client 11 and the client 12 are connected to the same sub-network by the switch 31 and the network address portions match, so the same group information is given. Further, the client 14 and the client 15 are connected to the same sub-network by the switch 32, and the network address portions match each other, so that the same group information is given, and the clients 17 to 19 are connected by the switch 33. Since the network address parts match, the same group information is given (see FIG. 4). The group information in this embodiment is a number, but may be a text, a symbol, or other identifier.

  The control information is various information used for communication control of the data distribution system according to the present invention. For example, the subnet mask of the IP addresses of the clients 11 to 19, the communication speed between the server 1 and the clients 11 to 19, The communication speed between the clients 11 to 19 is included.

  In response to a connection request from a client, the server 1 establishes a state (connection) in which data can be transmitted / received to / from the clients 11 to 19. FIG. 5 is a flowchart for explaining the establishment of the connection with the server by the control unit of the client.

  The control units 11a to 19a of the clients 11 to 19 can transmit / receive shared data and update data (to be described later) to and from the server 1 from a control program stored in the ROM or the operation units 11b to 19b. (Step S1: NO), and waits until an instruction to establish a connection with the server 1 is given (step S1: NO). When instructed to establish a connection with the server 1 (step S1: YES), the control units 11a to 19a of the clients 11 to 19 transmit a connection request to the server 1 (step S2). The connection request to the server 1 includes the IP address and subnet mask of the clients 11 to 19 that have requested connection.

  Then, the control units 11a to 19a of the clients 11 to 19 determine whether or not there is a response from the server 1 (step S3), and wait until there is a response (step S3: NO). When there is a response from the server 1 (step S3: YES), the control units 11a to 19a of the clients 11 to 19 transmit signals indicating connection permission to the server 1 (step S4), and establish a connection with the server 1. Establish (step S5). The response from the server 1 includes a connection permission for the connection requests from the clients 11 to 19 and a connection request to the clients 11 to 19.

FIG. 6 is a flowchart for explaining a connection process with the client by the control unit of the server.
The control unit 1a of the server 1 determines whether or not a connection request from the clients 11 to 19 has been received (step S11), and waits until a connection request from the clients 11 to 19 is received (step S11: NO). . The connection requests from the clients 11 to 19 include the entry numbers, IP addresses, and subnet masks of the clients 11 to 19. When the connection request from the clients 11 to 19 is received (step S11: YES), the control unit 1a of the server 1 sets the entry number, IP address, and subnet mask of the clients 11 to 19 that have received the connection request to the communication path information table. (Step S12). The entry numbers are recorded in the communication path information table together with the IP addresses in the order in which the connection requests from the clients 11 to 19 are received, and the entry numbers correspond to the IP addresses.

  And the control part 1a of the server 1 responds to the clients 11-19 which recorded the entry number and the IP address in the communication path information table (step S13). The response includes connection permission for connection requests from the clients 11 to 19 and connection requests to the clients 11 to 19. Next, the control unit 1a of the server 1 determines whether or not connection permission has been received from the clients 11 to 19 (step S14), and waits until connection permission is received from the clients 11 to 19 (step S14: NO). When connection permission is received from the clients 11 to 19 (step S14: YES), the control unit 1a of the server 1 establishes connections with the clients 11 to 19 (step S15). Note that when the server 1 receives a connection request from the clients 11 to 19 (step S11), the server 1 authenticates the clients 11 to 19, and executes the processes from step S12 onward only with the authenticated clients 11 to 19. May be.

  The server 1 in which the entry numbers and IP addresses of the clients 11 to 19 that transmitted the connection request to the server 1 are recorded in the communication path information table is transferred from the transfer source client that transfers the data transmitted from the server 1 and the transfer source client. Select processing to select the transfer destination client that receives the received data.

FIG. 7 is a flowchart for explaining a first embodiment of selection processing by the control unit of the server. It is assumed that no information is recorded in the communication path information table in the initial state.
The control unit 1a of the server 1 gives priority to the transfer source client from the grouping process (step S20) for giving the same group information to the clients connected to the same subnetwork, and the clients connected to the same subnetwork. And group priority processing for selecting a transfer destination client (step S30), and when the communication speed (response speed) between two clients is equal to or higher than a preset threshold, both clients are selected as a transfer source client and a transfer destination client. Threshold processing is executed in order (step S40), and the IP address of the transfer destination client is transmitted to the transfer source client (step S50). Note that the IP address of the transfer destination client may be transmitted to the transfer source client after performing the group priority process (step S30) without performing the threshold process (step S40) (step S50).

FIG. 8 is a flowchart for explaining grouping processing by the control unit of the server.
The control unit 1a of the server 1 sets a variable n indicating group information in the RAM, records an initial value (1 in the present embodiment) in the variable n (step S201), and sets a variable X indicating an entry number. The initial value (11 in this embodiment) is recorded in the variable X after being set in the RAM (step S202). Then, the control unit 1a of the server 1 sets n to the group information corresponding to the entry number X (No. X) (step S203). Next, the control unit 1a of the server 1 records X + 1 in the variable Y set in the RAM (step S204). Then, the control unit 1a of the server 1 determines whether or not the variable Y is larger than the maximum entry number (MAX No.) (step S205). The variable Y is MAXNo. If larger than (No at Step S205), No. described later. X is a process for determining whether or not the network address part of the IP address of the entry number Y (No. Y) matches, X corresponding to the client corresponding to X. The process of determining whether or not the client corresponding to Y is connected to the same subnetwork is terminated, and X is to be incremented, and the control unit 1a of the server 1 advances the process to step S211 to be described later. .

  If the variable Y is less than or equal to the maximum entry number (MAX No.) (step S205: NO), No. It is determined whether or not the group information corresponding to Y has not been set (step S206). No. When the group information corresponding to Y is set (step S206: NO), the control unit 1a of the server 1 advances the process to step S209 described later.

  No. If the group information corresponding to Y is not set (step S206: YES), the control unit 1a of the server 1 accesses the communication path information table of the storage unit 1e, and No. X and No. Refer to the IP address and subnet mask of Y. X and No. It is determined whether or not the network address part of the Y IP address matches (step S207). No. X and No. When the network address part of the IP address of Y matches (step S207: YES), the control part 1a of the server 1 N is set in the group information corresponding to Y (step S208).

  No. X and No. If the network address part of the IP address of Y does not match (step S207: NO), the control part 1a of the server 1 increments the variable Y (step S209), and the variable Y is MAXNo. It is determined whether it is larger than (step S210). The variable Y is MAXNo. If it is the following (step S210: NO), the control unit 1a of the server 1 returns the process to step S206.

  The variable Y is MAXNo. If it is greater than (step S210: YES), no. No. larger than X. Since all the comparisons with Y have been completed, the control unit 1a of the server 1 increments the variable X (step S211). It is determined whether it is larger than (step S212). The variable X is MAXNo. Is greater than (step S212: YES), the comparison between the variable X and the variable Y is all completed, so the control unit 1a of the server 1 ends the grouping process, and the group priority process (step S30, FIG. 7)).

  The variable X is MAXNo. If it is below (step S212: NO), the control unit 1a of the server 1 It is determined whether or not the group information corresponding to X is not set (step S213). No. If group information corresponding to X is set (step S213: NO), No. X and No. No. larger than X. Since all comparisons with Y have been completed, the control unit 1a of the server 1 returns the process to step S211. No. When the group information corresponding to X is not set (step S213: YES), the control unit 1a of the server 1 increments the variable n (step S214) and returns the process to step S203.

  The control unit 1a of the server 1 executes the group priority process after the grouping process is completed. FIG. 9 is a flowchart for explaining group priority processing by the control unit of the server.

The control unit 1a of the server 1 records an initial value (1 in this embodiment) in a variable n indicating group information (step S301), and sets a variable _Xn indicating an entry number in the group n in the RAM. Then, the initial value (11 in this embodiment) is recorded in the variable X _n (step S302). And the control part 1a of the server 1 is No. _Xn is selected (step S303). Next, the control unit 1a of the server 1 selects the selected No. The next entry number in the group n of X _n No. It is determined whether or not X _n +1 exists (step S304). No. When there is no X _n +1 (step S304: NO), the control unit 1a of the server 1 is No. No. is assigned to the transfer destination IP address corresponding to _Xn . The IP address of _Xn is recorded (step S305). Hereinafter, a client whose IP address and transfer destination IP address match is referred to as an isolated client. And the control part 1a of the server 1 complete | finishes a group priority process, and advances a process to a threshold value process (refer step S40, FIG. 7).

Next, the control unit 1a of the server 1 When X _n +1 exists, that is, No. When _Xn is not the maximum entry number in group n (step S304: YES), the control unit 1a of the server 1 determines No. No. is assigned to the transfer destination IP address corresponding to _Xn . Record the IP address of X _n +1 (step S306). Null is recorded at the transfer destination IP address corresponding to X _n +1 (step S307). Hereinafter, a client in which different addresses are recorded in the IP address and the transfer destination IP address is called a transfer source client, and a client in which null is recorded in the transfer destination IP address is called a transfer destination client. By the processing of step S306 and step S307, No. _Xn and No. A pair with X _n +1, that is, a pair of a transfer source client and a transfer destination client in the same subnet is established.

The control unit 1a of the server 1 records the X _n +2 to X _n (step S308), No. X _n is equal to or a maximum entry number in the group n (step S309). No. When _Xn is not the maximum entry number in group n (step S309: NO), the control unit 1a of the server 1 returns the process to step S303. For this reason, the client 19 in the present embodiment is connected to the same subnet as the client 17 and the client 18, but the client 17 and the client 18 form a pair of a transfer source client and a transfer destination client, and thus become an isolated client. (See FIG. 4).

No. When X _n is the maximum entry number in group n (step S309: YES), the control unit 1a of the server 1 increments n (step S310), and n is a value recorded in the group information. It is determined whether or not the maximum value is exceeded, that is, whether or not addresses or nulls are recorded in the transfer destination IP addresses for all groups (step S311). When n is less than or equal to the maximum value recorded in the group information, that is, when there is a group in which no address or null is recorded in the transfer destination IP address (step S311: NO), the control unit of the server 1 1a returns the process to step S303. When n exceeds the maximum value recorded in the group information, that is, when addresses or nulls are recorded in the transfer destination IP addresses for all groups (step S311: YES), the server 1 The control unit 1a ends the group priority processing, and advances the processing to threshold processing (see step S40, FIG. 7).

Next, threshold processing will be described. FIG. 10 is a flowchart for explaining threshold processing by the control unit of the server.
The control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S401), and extracts entry numbers corresponding to all isolated clients (step S402). Then, the control unit 1a of the server 1 records the isolated numbers corresponding to the extracted entry numbers in the control information of the communication path information table in ascending order corresponding to the entry numbers arranged in ascending order (step S403). Next, the control unit 1a of the server 1 sets the variable i in the RAM, records the minimum isolated number in the variable i (step S404), and makes a pair with the isolated number i, ie, whether or not the isolated number i + 1 exists. It is determined whether there are consecutive isolated numbers to be obtained (step S405).

  When the isolated number i + 1 does not exist, that is, when there is no continuous isolated number paired with the isolated number i (step S405: NO), the control unit 1a of the server 1 accesses the storage unit 1e to access the communication path information table. The transfer destination IP address is transmitted to the transfer source client (step S50, see FIG. 7). When the isolated number i + 1 exists, that is, when there are continuous isolated numbers that are paired with the isolated number i (step S405: YES), the control unit 1a of the server 1 sets the variable j in the RAM and sets it as the variable j. i + 1 is recorded (step S406).

  Then, the control unit 1a of the server 1 requests the client corresponding to the isolated number i or the isolated number j to measure the communication speed (response speed) between both clients corresponding to the isolated number i and the isolated number j (step S407). ). The control unit 1a of the server 1 determines whether or not a communication speed (response speed) is returned from the client corresponding to the isolated number i or the isolated number j (step S408), and waits until it is returned (step S408: NO). When the communication speed is returned from the client corresponding to the isolated number i or the isolated number j (step S408: YES), the controller 1a of the server 1 determines that the returned communication speed is equal to or higher than a threshold set in advance in the RAM. It is determined whether or not there is (step S409). As a technique for measuring the communication speed (response speed) between clients, there is a clock synchronization system to be described later in consideration of transmission / reception delay by NTP (Network Time Protocol) using UDP having a high packet transmission speed.

  When the returned communication speed is equal to or higher than the threshold set in the RAM in advance (step S409: YES), the control unit 1a of the server 1 sets the IP address corresponding to the isolated number j to the transfer destination IP address corresponding to the isolated number i. The address is recorded (overwritten) (step S410), and null is recorded (overwritten) in the isolated number j at the transfer destination IP address corresponding to the isolated number j (step S411). At this time, the isolated client corresponding to the isolated number i is a transfer source client, and the isolated client corresponding to the isolated number j is a transfer destination client.

  Then, the control unit 1a of the server 1 records i + 2 in the variable i (step S412), and measures whether or not the isolated number i is larger than the maximum isolated number, that is, the communication speed between all isolated clients. It is determined whether or not (step S413). When the isolated number i is equal to or less than the maximum value of the isolated number, that is, when there is an isolated client whose communication speed between clients is not measured (step S413: NO), the control unit 1a of the server 1 proceeds to step S405. To return. When the isolated number i is larger than the maximum isolated number, that is, when the communication speed between all isolated clients is measured (step S413: YES), the control unit 1a of the server 1 ends the threshold processing and stores it. The unit 1e is accessed, and the transfer destination IP address is transmitted to the transfer source client with reference to the communication path information table (step S50, see FIG. 7).

  In the above-described step S409, when the returned communication speed is less than the threshold value previously set in the RAM (step S409: NO), the control unit 1a of the server 1 increments the variable j (step S414), and the isolated number Whether or not j is larger than the maximum isolated number, that is, measurement of the communication speed between the client corresponding to isolated number i and the client corresponding to isolated number j having a larger value than isolated number i has been completed. It is determined whether or not (step S415). When the isolated number j is equal to or less than the maximum value of the isolated number (step S415: NO), the control unit 1a of the server 1 returns the process to step S407. When the isolated number j is larger than the maximum isolated number (step S415: YES), the control unit 1a of the server 1 advances the process to step S412.

  In step S407, the client that is requested to measure the communication speed between the two clients corresponding to the isolated number i and the isolated number j calculates the communication speed between the two clients. FIG. 11 is a flowchart for explaining communication speed calculation processing by the control unit of the client corresponding to the isolated number i or the isolated number j.

  One of the clients corresponding to the isolated number i and the isolated number j (one client) is controlled by the control unit from the server 1 and the other of the two clients corresponding to the isolated number i and the isolated number j (other clients). ) Is determined whether or not it is requested to measure the communication speed (step S421), and waits until the request is made (step S421: NO). When there is the request (step S421: YES), the control unit of one client requests the other client to measure the communication speed (step S422). Then, the control unit of one client determines whether or not there is a response from another client (step S423), and waits until there is a response (step S423: NO).

  When there is a response from another client (step S423: YES), the control unit of one client is included in the response from the other client at the time when the one client requested the other client. The time when another client received a request from one client and the time when another client sent a response, the time when one client received a response from another client, and one client The communication speed between one client and another client is calculated based on the delay between other clients and the like (step S424).

  When a response is received from another client, the control unit of one client is included in the response from the other client, and the time when the other client receives a request from the one client and other The time when a client responds and the time when a response from another client is received are recorded in its own RAM. It is assumed that the delay between one client and another client is set in advance in the RAM of one client.

As a technique for measuring the communication speed between clients, there is a clock synchronization system that takes into account a delay in transmission and reception by NTP using UDP having a high packet transmission speed. Specifically, when the delay between one client and another client is equal in both directions, the sum of the time when one client requests the other client and the time when the other client sends a response The difference between the time when the other client receives the request from the one client and the sum of the times when the other client transmits the response is calculated, and the half of the difference is The difference in time at the time of the timer possessed by another client is taken, and the communication speed is obtained by adding or subtracting the difference to the time at the time of one client or another client. By using UDP, broadcast communication is possible, and the communication speed between one client and a plurality of other clients can be quickly calculated.
Then, the control unit of one client responds to the server 1 (step S425).

In step S422, the other client that has received the measurement request from the one client responds to the one client.
FIG. 12 is a flowchart for explaining processing in the control unit of another client that has received a communication speed measurement request from one client.
In step S422, the control unit of the other client determines whether or not the measurement of the communication speed between the one client and the other client is requested (step S431), and waits until the request is made (step S431). : NO). When the request is made (step S431: YES), the control unit of the other client responds with information indicating the time when the request is received and the time when the response is made (step S432).

FIG. 13 is a flowchart for explaining a second embodiment of the selection process by the control unit of the server. It is assumed that no information is recorded in the communication path information table in the initial state.
The control unit 1a of the server 1 gives priority to the transfer source client from the grouping process (step S20) for giving the same group information to the clients connected to the same subnetwork, and the clients connected to the same subnetwork. And group priority processing (step S30) for selecting a transfer destination client, and the fastest processing (step S60) for selecting both clients as a transfer source client and a transfer destination client when the communication speed between the two clients is the fastest. The IP address of the transfer destination client is transmitted to the transfer source client (step S50). Note that the IP address of the transfer destination client may be transmitted to the transfer source client after performing the group priority process (step S30) without performing the fastest process (step S60) (step S50).

  FIG. 14 is a flowchart for explaining the fastest processing by the control unit of the server.

  The control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S601), and extracts entry numbers corresponding to all isolated clients (step S602). Then, the control unit 1a of the server 1 records the isolated numbers corresponding to the extracted entry numbers in the control information of the communication path information table in ascending order corresponding to the entry numbers arranged in ascending order (step S603). Next, the control unit 1a of the server 1 sets the variable i in the RAM, records the minimum isolated number in the variable i (step S604), and makes a pair with the isolated number i, that is, whether or not the isolated number i + 1 exists. It is determined whether there are consecutive isolated numbers to be obtained (step S605).

  When the isolated number i + 1 does not exist (step S605: NO), the control unit 1a of the server 1 ends the fastest processing, accesses the storage unit 1e, refers to the communication path information table, and transfers the transfer destination IP to the transfer source client. The address is transmitted (step S50, see FIG. 13). When the isolated number i + 1 exists (step S605: YES), the control unit 1a of the server 1 sets the variable j in the RAM and records i + 1 in the variable j (step S606).

  Then, the control unit 1a of the server 1 requests the client corresponding to the isolated number i or the isolated number j to measure the communication speed between both clients corresponding to the isolated number i and the isolated number j (step S607). At this time, the communication speed between both clients is measured by both clients corresponding to the isolated number i and the isolated number j (see FIGS. 11 and 12). It is determined whether or not the communication speed is returned from the client corresponding to the isolated number i or the isolated number j (step S608) and waits until it is returned (step S608: NO). When the communication speed is returned from the client corresponding to the isolated number i or the isolated number j (step S608: YES), the control unit 1a of the server 1 sets the communication speed to the communication information corresponding to the isolated number i or the isolated number j. It is recorded in the control information of the table (step S609), and the variable j is incremented (step S610). Next, the control unit 1a of the server 1 determines whether or not the isolated number j is larger than the maximum value of the isolated number, that is, the client corresponding to the isolated number i and the isolated number j that is a larger number than the isolated number i. It is determined whether or not the communication speed has been measured with all the clients (step S611). When the isolated number j is equal to or less than the maximum value of the isolated number, that is, when there is a client corresponding to the isolated number j whose communication speed is not measured with the client corresponding to the isolated number i (step S611: NO) ), The control unit 1a of the server 1 returns the process to step S607.

  When the isolated number j is larger than the maximum isolated number, that is, the communication speed is measured between the client corresponding to the isolated number i and all the clients corresponding to the isolated number j that is larger than the isolated number i. In the case (step S611: YES), the control unit 1a of the server 1 refers to the communication information table in the storage unit 1e, extracts the fastest communication speed (step S612), and forwards the IP address corresponding to the isolated number i. The IP address corresponding to the fastest communication speed is recorded (overwritten) in the address (step S613). Next, the control unit 1a of the server 1 records (overwrites) null in the transfer destination IP address of the entry number corresponding to the fastest communication speed (step S614). At this time, the isolated client corresponding to the isolated number i is a transfer source client, and the isolated client corresponding to the isolated number j is a transfer destination client.

  Then, the control unit 1a of the server 1 records i + 2 in the variable i (step S615), and measures whether or not the isolated number i is larger than the maximum value of the isolated number, that is, the communication speed between all isolated clients. It is determined whether or not the pair of isolated clients corresponding to the fastest communication speed is the transfer source client and the transfer destination client (step S616). When the isolated number i is equal to or less than the maximum value of the isolated number, that is, when there is a pair of isolated clients that do not measure the communication speed (step S616: NO), the control unit 1a of the server 1 proceeds to step S605. return. When the isolated number i is larger than the maximum value of the isolated number, that is, when the communication speed between all the isolated clients is measured, and the pair of isolated clients corresponding to the fastest time is set as the transfer source client and the transfer destination client (step S616) : YES), the control unit 1a of the server 1 terminates the fastest processing, accesses the storage unit 1e, refers to the communication path information table, and transmits the transfer destination IP address to the transfer source client (step S50, FIG. 13).

  The grouping process (step S20) and the group priority process (step S30) are the same as those in the first embodiment of the selection process, and detailed description thereof is omitted.

FIG. 15 is a flowchart for explaining a third embodiment of the selection process by the control unit of the server. It is assumed that no information is recorded in the communication path information table in the initial state.
The control unit 1a of the server 1 performs server / client communication speed measurement processing (step S70) for measuring the communication speed between the server 1 and the client, the communication speed (response speed) between the server 1 and the client, and the communication speed between the clients (response speed). Based on the response speed, an inter-client communication path determination process (step S80) for determining a communication path between clients is sequentially executed, and the IP address of the transfer destination client is transmitted to the transfer source client (step S50).

  FIG. 16 is a flowchart for explaining server / client communication speed measurement processing in the control unit of the server.

  As shown in FIG. 16, the control unit 1a of the server 1 requests the client to measure the communication speed (response speed) between the server 1 and the client (step S701). At this time, the control unit 1a of the server 1 refers to the timer and records the time when the measurement of the communication speed (response speed) between the server 1 and the client is requested in the RAM. The client responds to the request from the server 1 (refer to FIG. 12 by replacing “one client” with “server 1” and “other clients” with “client” in steps S431 and S432). The control unit 1a of the server 1 determines whether or not there is a response from the client (step S702), and waits until there is a response (step S702: NO). When there is a response from the client (step S702: YES), the control unit 1a of the server 1 includes the time when the server 1 requests the client and the time when the client receives the request. The first communication speed is calculated based on the time when the client transmits the response, the time when the server 1 receives the response, the delay between the server 1 and the client, and the like (step S703). In addition, when there is a response from the client, the control unit 1a of the server 1 stores the time when the client receives the request, the time when the client transmits the response, and the time when the server 1 receives the response in the RAM. Record. The delay between the server 1 and the client is set in advance in the RAM of the server 1. As a technique for measuring the communication speed between the server 1 and the client, there is a clock synchronization system that takes into account a delay in transmission and reception by NTP using UDP having a high packet transmission speed.

  Then, the control unit 1a of the server 1 records the calculated first communication speed (response speed) in the control information of the communication path information table corresponding to the responding client (step S704). Then, the control unit 1a of the server 1 determines whether or not the first communication speed (response speed) between the server 1 and all clients has been recorded (step S705).

  When there is a client that does not record the first communication speed (response speed) (step S705: NO), the control unit 1a of the server 1 returns the process to step S701. When the first communication speed (response speed) between the server 1 and all the clients is recorded (step S705: YES), the control unit 1a of the server 1 ends the server 1 / client communication speed measurement process, and the inter-client communication A route determination process is executed (step S80, see FIG. 15).

  FIG. 17 is a flowchart for explaining a communication path determination process between clients in the control unit of the server.

  The control unit 1a of the server 1 determines whether or not all the first communication speeds (response speeds) between each client and the server 1 are equal to or higher than a predetermined speed set in the RAM (step S801). When all of the first communication speeds (response speeds) between each client and the server 1 are equal to or higher than the predetermined speed (step S801: YES), the control unit 1a of the server 1 performs the above-described grouping process (step S20), group The priority process (step S30) and the fastest process (step S60) are executed in order. Note that threshold processing (step S40) may be executed instead of the fastest processing (step S60). Then, the control unit 1a of the server 1 terminates the inter-client communication path determination process, accesses the storage unit 1e, refers to the communication path information table, and transmits the transfer destination IP address to the transfer source client (step S50, FIG. 15).

  When there is a client whose first communication speed with the server 1 is lower than the predetermined speed (step S801: NO), the control unit 1a of the server 1 extracts one client corresponding to the first communication speed lower than the predetermined speed. (Step S802), and requests the one client to measure the second communication speed (response speed) between the one client and another client (Step S803). At this time, the second communication speed (response speed) between the one client and another client is calculated in one client, and the one client responds to the server 1 together with the second communication speed (FIGS. 11 and 12). reference). The control unit 1a of the server 1 designates a client having a first communication speed equal to or higher than a predetermined speed as another client, and one client calculates a second communication speed with the designated other client. It may be.

  Next, the control unit 1a of the server 1 determines whether or not there is a response from one client (step S804), and waits until there is a response (step S804: NO). When there is a response from one client (step S804: YES), the control unit 1a of the server 1 accesses the storage unit 1e and sets the second communication speed included in the response to communication path information corresponding to the other client. It is recorded in the control information of the table (step S805). Then, the control unit 1a of the server 1 determines whether or not the second communication speed is faster than the first communication speed (step S806). When the second communication speed is slower than the first communication speed (step S806: NO), the control unit 1a of the server 1 uses the second communication speed between one client and all other clients as control information. It is determined whether or not recording has been performed (step S807). When the second communication speed between one client and all other clients is recorded in the control information (step S807: YES), the control unit 1a of the server 1 accesses the storage unit 1e to access the one client A flag is set in the control information of the communication path information table corresponding to (step S809). And the control part 1a of the server 1 returns a process to step S801. The flag indicates that the flag is ignored in step S801. In step S801, the first communication speed between the client and the server 1 in which the flag exists is excluded from the determination target.

  When there is a second communication speed that is not recorded in the control information (step S807: NO), the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table, and the entry number is other. The next largest client (except one client) is designated as another new client (step S808), and the process returns to step S803.

  In step S806, when the second communication speed is higher than the first communication speed (step S806: YES), the control unit 1a of the server 1 sets the IP address of one client to the transfer destination IP address corresponding to another client. (Step S810), and null is recorded at the transfer destination IP address corresponding to one client (step S811). At this time, another client becomes a transfer source client, and one client becomes a transfer destination client. Then, the control unit 1a of the server 1 locks the description of the transfer destination IP address recorded in step S810 and step S811 (step S812), and advances the process to step S809. Due to the lock, in the group priority process (step S30), the fastest process (step S60), and the threshold process (step S40), one client and another client are excluded from the processing targets. The lock can be released as necessary.

  When the selection process for selecting the transfer source client and the transfer destination client is completed, the data distribution system according to the present invention selects the selected transfer source client and transfer destination client before transmitting data from the server 1 to the transfer source client. Establish a connection between

  FIG. 18 is a flowchart for explaining connection establishment processing by the control unit of the client, and FIG. 19 is a conceptual diagram showing establishment of a connection between the transfer source client and the transfer destination client.

  The control unit of the client determines whether or not the transfer destination IP address has been received from the server 1 (step S91). When the transfer destination IP address is received from the server 1, that is, when designated as a transfer source client or an isolated client (step S91: YES), the control unit of the client matches the received transfer destination IP address with its own IP address. It is determined whether or not to perform (step S92). When the received transfer destination IP address matches its own IP address, that is, when designated as an isolated client (step S92: YES), the control unit of the isolated client ends the connection establishment process.

  When the received transfer destination IP address does not match with its own IP address, that is, when designated as the transfer source client (step S92: NO), the control unit of the transfer source client, based on the received transfer destination IP address, A connection request is made to the transfer destination client (step S93), it is determined whether or not there is a response from the transfer destination client (step S94), and the process waits until a response is received (step S94: NO). When there is a response from the transfer destination client (step S94: YES), the control unit of the transfer source client transmits a connection permission to the transfer destination client (step S95), and establishes a connection with the transfer destination client (step S95). S96). Then, the control unit of the transfer source client transmits information indicating that the connection has been established to the server 1 (step S97). Note that the response from the transfer destination client includes a connection permission and a connection request to the transfer source client.

  When the transfer destination IP address is not received from the server 1 in step S91 described above, that is, when the transfer source client or the isolated client is not designated (step S91: NO), the control unit of the client receives from the transfer source client. It is determined whether or not a connection is requested (step S98). When the connection is not requested from the transfer source client, that is, when it is not designated as any of the transfer source client, the transfer destination client and the isolated client (step S98: NO), the control unit of the client proceeds to step S91. To return.

  When a connection is requested from the transfer source client, that is, when the transfer destination client is designated (step S98: YES), the control unit of the transfer destination client permits the connection to the transfer source client and connects to the transfer source client. It responds to the transfer source client together with the connection request (step S99). Then, the control unit of the transfer destination client determines whether or not connection permission is received from the transfer source client (step S100), and waits until connection permission is received (step S100: NO). When the connection permission is received, the control unit of the transfer destination client establishes a connection with the transfer source client (step S101).

The data distribution system according to the present invention updates shared data owned by other clients and the server 1 when shared data is updated by one client.
FIG. 20 is a flowchart for explaining update processing by the control unit of the transfer source client when the shared data is updated in the transfer source client.

  The control unit of the transfer source client determines whether or not the shared data is changed by an input from the operation units 11b to 19b and an instruction to update the shared data is input (step S111), and an instruction to update the shared data is issued. It waits until it is input (step S111: NO). When a command to update shared data is input (step S111: YES), the control unit of the transfer source client updates the shared data (step S112), and updates its own IP address (transfer source IP address) and update data ( The updated shared data or the difference data of the shared data before and after the update) is transmitted to the server 1 (step S113). At this time, the server 1 that has received the transfer source IP address and the update data updates its own shared data and refers to the communication path information table with the transfer source IP address excluding the received transfer source IP address as the destination. Send update data. Then, the control unit of the transfer source client transfers the update data to the transfer destination client (step S114).

When the transfer destination client receives the update data, it updates the shared data owned by itself.
FIG. 21 is a flowchart for explaining shared data update processing by the control unit of the transfer destination client when update data is received.

  The transfer destination client determines whether or not update data is received from the transfer source client (step S121), and waits until update data is received (step S121: NO). When the update data is received from the transfer source client (step S121: YES), the control unit of the transfer destination client accesses the storage unit 1e and updates the shared data (step S122).

  FIG. 22 is a flowchart for explaining update processing by the control unit of the transfer destination client when the shared data is updated in the transfer destination client.

  The control unit of the transfer destination client determines whether or not the shared data is changed by an input from the operation units 11b to 19b and an instruction to update the shared data is input (step S131), and an instruction to update the shared data is issued. Wait until it is input (step S131: NO). When a command for updating the shared data is input (step S131: YES), the control unit of the transfer destination client accesses the storage units 11e to 19e to update the shared data (step S132), and the own IP address ( The transfer destination IP address) and the update data (updated shared data or difference data between the shared data before and after the update) are transmitted to the transfer source client (step S133). Note that the transfer source client is operating normally, and in response to the transmission of data to the transfer source client in step S133, the transfer source client responds to the transfer destination client that it has received the transfer destination IP address and the update data. . The transfer destination client that has received the response ends the update process described above.

  The transfer source client that has received the transfer destination IP address and the update data updates its own shared data. FIG. 23 is a flowchart for explaining update processing by the control unit of the transfer source client when the transfer destination IP address and the update data are received from the transfer destination client.

  The control unit of the transfer source client determines whether or not the transfer destination IP address and the update data are received from the transfer destination client (step S141), and waits until the transfer destination IP address and the update data are received (step S141). S141: NO). When the transfer destination IP address and the update data are received (step S141: YES), the control unit of the transfer source client accesses the storage units 11e to 19e to update the shared data (step S142), and the own IP address (Transfer source IP address) and update data are transmitted to the server 1 (step S143). At this time, the server 1 that has received the transfer source IP address and the update data updates its own shared data and refers to the communication path information table with the transfer source IP address excluding the received transfer source IP address as the destination. Send update data. The transfer source client responds to the transfer destination client that it has received the transfer destination IP address and the update data.

The server 1 that has received the update data updates the shared data that it owns.
FIG. 24 is a flowchart for explaining shared data update processing by the control unit of the server when update data is received.

  The control unit 1a of the server 1 determines whether or not the transfer source IP address and update data are received (step S151), and waits until the transfer source IP address and update data are received (step S151: NO). When the transfer source IP address and the update data are received (step S151: YES), the control unit 1a of the server 1 accesses the storage unit 1e and updates the shared data (step S152). Then, the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S153), and transmits update data with the transfer source IP address (excluding the received transfer source IP address) as the destination. (Step S154).

The transfer source client that has received the update data transmitted by the server 1 in step S154 updates the shared data.
FIG. 25 is a flowchart for explaining shared data update processing by the control unit of the transfer source client when update data is received from the server.

  The control unit of the transfer source client determines whether or not update data has been received from the server 1 (step S155), and waits until update data is received (step S155: NO). When the update data is received from the server 1 (step S155: YES), the control unit of the transfer source client accesses the storage units 11e to 19e and updates the shared data based on the received update data (step S156). Then, the control unit of the transfer source client determines whether or not a connection is established with the transfer destination client (step S157), and waits until the connection is established (step S157: NO). When a connection is established with the transfer destination client (step S157: YES), the control unit of the transfer source client transfers the update data to the transfer destination client (step S158).

Next, a case where one client leaves the data distribution system according to the present invention will be described.
FIG. 26 is a flowchart for explaining an exit process executed by the control unit of the transfer source client when the transfer source client leaves the data distribution system.

  The control unit of the transfer source client determines whether or not an exit command has been input by an operation of the operation units 11b to 19b by the user or an exception process of the control program (step S161), and waits until the exit command is input. (Step S161: NO). When the exit command is input (step S161: YES), the control unit of the transfer source client transmits the disconnection data to the transfer destination client including the disconnection request to the transfer destination client and the control information necessary for exit (step S161). S162). Next, the control unit of the transfer source client determines whether or not there is a response from the transfer destination client (step S163), and waits until there is a response (step S163: NO). The response from the transfer destination client includes disconnection permission and disconnection request. When there is a response from the transfer destination client (step S163: YES), the control unit of the transfer source client transmits a disconnection permission to the transfer destination client and disconnects the connection with the transfer destination client (step S164).

  Then, the control unit of the transfer source client transmits to the server 1 a disconnect request to the server 1 and exit data including control information necessary for exit, and requests the server 1 to disconnect the connection (step S165). Next, the control unit of the transfer source client determines whether or not there is a response from the server 1 (step S166), and waits until there is a response (step S166: NO). The response from the server 1 includes a disconnection permission and a disconnection request from the server 1. When there is a response from the server 1 (step S166: YES), the control unit of the transfer source client transmits a disconnection permission to the server 1 and disconnects the connection with the server 1 (step S167).

  In step S162, the transfer destination client that has received the exit data from the transfer source client executes processing for the transfer source client to leave the data distribution system. FIG. 27 is a flowchart for explaining processing by the control unit of the transfer destination client when the leaving data is received from the transfer source client.

  The control unit of the transfer destination client determines whether or not the exit data has been received from the transfer source client (step S171), and waits until the exit data is received from the transfer source client (step S171: NO). The exit data includes a disconnect request. When the leaving data is received from the transfer source client (step S171: YES), the control unit of the transfer destination client responds to the transfer source client (step S172). The response includes a disconnection permission and a disconnection request to the transfer source client. Next, the control unit of the transfer destination client determines whether or not disconnection permission has been received from the transfer source client (step S173), and waits until reception of disconnection permission (step S173: NO). When disconnection permission is received from the transfer source client (step S173: YES), the control unit of the transfer destination client disconnects the connection with the transfer source client (step S174).

  In step S165, the server 1 that has received the leaving data transmitted from the transfer source client disconnects the connection with the transfer source client. FIG. 28 is a flowchart for explaining processing for cutting off the connection with the transfer source client by the control unit of the server.

  The control unit 1a of the server 1 determines whether or not exit data is received from the transfer source client (step S181), and waits until the exit data is received from the transfer source client (step S181: NO). When the leaving data is received from the transfer source client (step S181: YES), the control unit 1a of the server 1 responds to the transfer source client (step S182). The response includes a disconnection permission and a disconnection request to the transfer source client. Next, the control unit 1a of the server 1 determines whether or not a disconnection permission is received from the transfer source client (step S183), and waits until a disconnection permission is received from the transfer source client (step S183: NO). When disconnection permission is received from the transfer source client (step S183: YES), the control unit 1a of the server 1 disconnects the connection with the transfer source client (step S184).

  Then, the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S185), and transfers the IP address of the transfer destination client to the transfer destination IP address of the transfer destination client corresponding to the transfer source client. Is recorded (overwritten) (step S186). At this time, the transfer destination client becomes an isolated client. Next, the control unit 1a of the server 1 deletes the information of the transfer source client that has disconnected the connection from the communication path information table (step S187), and determines whether or not there are a plurality of isolated clients (step S188). When there is a single isolated client (step S188: NO), the control unit 1a of the server 1 ends the process.

  When there are a plurality of isolated clients (step S188: YES), the control unit 1a of the server 1 executes the above-described grouping processing, group priority processing, fastest processing, threshold processing, or the like between the isolated clients to perform communication. The route information table is reconstructed (step S189). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to all the transfer source clients or the transfer source clients newly designated in step S189 (step S190). Note that if the transfer source client and transfer destination client cannot be newly designated from a plurality of isolated clients even after executing the grouping process, the group priority process, the fastest process, or the threshold process in step S189, step S190 is not executed. .

  Next, a case where the transfer destination client leaves the data distribution system will be described. FIG. 29 is a flowchart for explaining an exit process executed by the control unit of the transfer destination client when the transfer destination client leaves the data distribution system.

  The control unit of the transfer destination client determines whether or not an exit command has been input by the operation of the operation units 11b to 19b by the user or an exception process of the control program (step S251), and waits until the exit command is input. (Step S251: NO). When the exit command is input (step S251: YES), the control unit of the transfer destination client transmits the exit data to the transfer source client (step S252). The leaving data includes a disconnection request to the transfer source client. Then, the control unit of the transfer destination client determines whether or not there is a response from the transfer source client (step S253), and waits for a response from the transfer source client (step S253: NO). The response from the transfer source client includes a disconnection request to the transfer destination client.

  When there is a response from the transfer source client (step S253: YES), the control unit of the transfer destination client transmits a disconnect permission for the disconnect request to the transfer source client, and disconnects the connection with the transfer source client (step S254). ).

  The transfer source client that has received the exit data transmitted from the transfer destination client in step S252 executes processing for the transfer destination client to leave the data distribution system. FIG. 30 is a flowchart for explaining processing executed by the control unit of the transfer source client when the leaving data is received from the transfer destination client.

  The control unit of the transfer source client determines whether or not exit data including disconnection information is received from the transfer destination client (step S261), and waits until the exit data is received from the transfer destination client (step S261: NO). . When the exit data is received from the transfer destination client (step S261: YES), the control unit of the transfer source client responds to the transfer destination client (step S262). The response includes a disconnect permission and a disconnect request to the transfer destination client. Next, the control unit of the transfer source client determines whether or not disconnection permission has been received from the transfer destination client (step S263), and waits until reception of disconnection permission (step S263: NO). When the disconnection permission is received (step S263: YES), the control unit of the transfer source client disconnects the connection with the transfer destination client (step S264), and transmits the exit data of the transfer destination client to the server 1 (step S264). S265).

  The server 1 that has received the withdrawal data of the transfer destination client from the transfer source client executes processing for the transfer destination client to leave the data distribution system. FIG. 31 is a flowchart for explaining the processing executed by the control unit of the server when the exit data of the transfer destination client is received from the transfer source client.

  The control unit 1a of the server 1 determines whether or not the transfer destination client's exit data has been received from the transfer source client (step S271), and waits until the transfer destination client's exit data is received (step S271: NO). . When the withdrawal data of the transfer destination client is received (step S271: YES), the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S272), and transfers the transfer source client. The IP address of the transfer source client is recorded (overwritten) in the destination IP address (step S273). At this time, the transfer source client becomes an isolated client. Then, the control unit 1a of the server 1 deletes the information of the relocated transfer destination client from the communication path information table (step S274), and determines whether or not there are a plurality of isolated clients (step S275). When there is a single isolated client (step S275: NO), the control unit 1a of the server 1 ends the process.

  When there are a plurality of isolated clients (step S275: YES), the control unit 1a of the server 1 executes the above-described grouping process, group priority process, fastest process, threshold process, etc. between the isolated clients, and the communication path The information table is reconstructed (step S276). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to the transfer source client newly specified in step S276 (step S277). If the transfer source client and transfer destination client cannot be newly designated from a plurality of isolated clients even after executing the grouping process, the group priority process, the fastest process, or the threshold process in step S276, step S277 is not executed. .

  Next, a case where an isolated client leaves the data distribution system will be described. FIG. 32 is a flowchart for explaining the exit processing from the data distribution system by the control unit of the isolated client.

  The control unit of the isolated client determines whether or not an exit command is input by the operation of the operation units 11b to 19b by the user or an exception process of the control program (step S281), and waits until the exit command is input (step S281). Step S281: NO). When the exit command is input (step S281: YES), the control unit of the isolated client transmits the exit data to the server 1 (step S282). The exit data includes a disconnection request to the server 1. Then, the control unit of the isolated client determines whether or not there is a response from the server 1 (step S283), and waits until there is a response from the server 1 (step S283: NO). The response from the server 1 includes a disconnection permission and a disconnection request from the server 1.

  When there is a response from the server 1 (step S283: YES), the control unit of the isolated client transmits a disconnection permission to the server 1 and disconnects the connection with the server 1 (step S284).

  In step S282, the server 1 that has received the exit data from the isolated client executes processing for the isolated client to exit the data distribution system. FIG. 33 is a flowchart for explaining processing executed by the control unit of the server that has received exit data from an isolated client.

  The control unit 1a of the server 1 determines whether or not exit data has been received from the isolated client (step S291), and waits until the exit data is received from the isolated client (step S291: NO). The exit data includes a disconnection request from an isolated client. When the leaving data is received from the isolated client (step S291: YES), the control unit 1a of the server 1 responds to the isolated client (step S292). The response includes a disconnection permission and a disconnection request to the isolated client. Next, the control unit 1a of the server 1 determines whether or not a disconnection permission is received from the isolated client (step S293), and waits until a disconnection permission is received from the isolated client (step S293: NO).

  When the disconnection permission is received from the isolated client (step S293: YES), the control unit 1a of the server 1 disconnects the connection with the isolated client (step S294). Then, the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S295), and deletes the information of the isolated client that has disconnected the connection from the communication path information table (step S296).

  Next, processing of the server 1 when a new client is connected to the server 1 after creating the communication path information table will be described. FIG. 34 is a flowchart illustrating processing executed by the control unit of the server when a new client is connected to the server after creating the communication path information table.

  The control unit 1a of the server 1 determines whether or not a connection request from a newly connected client has been received (step S351), and waits until a connection request from the client is received (step S351: NO). The connection request from the client includes the client entry number, IP address, subnet mask, and the like. When the connection request from the client is received (step S351: YES), the control unit 1a of the server 1 records the entry number, IP address, and subnet mask of the client that has received the connection request in the communication path information table (step S352). ). The entry number is recorded in the communication path information table together with the IP address in the order in which the connection request from the client is received, and the entry number corresponds to the IP address.

  Next, the control unit 1a of the server 1 responds to the new client that has received the connection request (step S353). The response includes a permission to connect to a new client and a connection request. Then, the control unit 1a of the server 1 determines whether or not a connection permission has been received from a new client (step S354), and waits until a connection permission is received from a new client (step S354: NO). When connection permission is received from a new client (step S354: YES), the control unit 1a of the server 1 establishes a connection with the new client (step S355).

  Next, the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table (step S356), and records the new client IP address in the new client transfer destination IP address (step S357). ). At this time, the new client becomes an isolated client. Then, the control unit 1a of the server 1 determines whether or not there are a plurality of isolated clients (step S358). When there is a single isolated client (step S358: NO), the control unit 1a of the server 1 performs processing. finish.

  When there are a plurality of isolated clients (step S358: YES), the control unit 1a of the server 1 executes the above-described grouping process, group priority process, fastest process, threshold process, etc. between the isolated clients, and the communication path The information table is reconstructed (step S359). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to the transfer source client newly specified in step S359 (step S360). Note that if the transfer source client and transfer destination client cannot be newly designated from a plurality of isolated clients even after executing the grouping process, the group priority process, the fastest process, or the threshold process in step S359, step S360 is not executed. .

  Next, failure countermeasure processing executed by the control unit of the transfer destination client when the shared data is updated in the transfer destination client and a failure has occurred in the transfer source client will be described. FIG. 35 is a flowchart for explaining failure countermeasure processing executed by the control unit of the transfer destination client when the shared data is updated in the transfer destination client and a failure has occurred in the transfer source client.

  The control unit of the transfer destination client changes its own IP address (transfer destination IP address) and update data (update) when the shared data is changed by the operation of the operation units 11b to 19b and an instruction to update the shared data is input. The shared data or the difference data of the shared data before and after the update) is transmitted to the transfer source client (step S371). At this time, the control unit of the transfer destination client counts the number of times of transmission to the transfer source client and stores it in the RAM. Then, the control unit of the transfer destination client starts a timer and determines whether or not a response indicating that the transfer destination IP address and the update data are received from the transfer source client is within a predetermined time (step S372). If there is a response indicating that the transfer destination IP address and the update data have been received from the transfer source client (step S372: YES), the process ends.

  When there is no response indicating that the transfer destination IP address and the update data have been received from the transfer source client (step S372: NO), the control unit of the transfer destination client transmits the transfer destination IP address and the update data. Are recorded in the RAM, and it is determined whether or not the transfer destination IP address and the update data have been transmitted a predetermined number of times (step S373). The predetermined number of times is set in the RAM when the transfer destination client is activated. When the number of transmissions is less than the predetermined number (step S373: NO), the control unit of the transfer destination client returns the process to step S371. When the number of transmissions is equal to or greater than the predetermined number (step S373: YES), the control unit of the transfer destination client transmits information indicating that a failure has occurred in the transfer source client (transfer source failure information) to the server 1 (step S37). S374). Then, the control unit of the transfer destination client transmits reset information to the transfer source client and forcibly disconnects the connection with the transfer source client (step S375).

  The server 1 that has received the transfer source failure information executes a deletion process for deleting the information of the transfer source client in which the failure has occurred from the communication path information table. FIG. 36 is a flowchart for explaining a deletion process executed by the control unit of the server when shared data is updated in the transfer destination client and a failure has occurred in the transfer source client.

  The control unit 1a of the server 1 determines whether or not the transfer source failure information has been received (step S381), and waits until the transfer source failure information is received (step S381: NO). When the transfer source failure information is received (step S381: YES), the control unit 1a of the server 1 transmits reset information to the transfer source client and forcibly disconnects the connection with the transfer source client (step S382). . Next, the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table, and deletes the information of the transfer source client (step S383). At this time, the IP address of the transfer destination client is recorded (overwritten) in the transfer destination IP address of the transfer destination client, and the transfer destination client becomes an isolated client. Then, the control unit 1a of the server 1 determines whether or not there are a plurality of isolated clients (step S384), and when there is a single isolated client (step S384: NO), the process ends.

  When there are a plurality of isolated clients (step S384: YES), the control unit 1a of the server 1 executes the above-described grouping processing, group priority processing, fastest processing, threshold processing, or the like between the isolated clients, and performs communication. The route information table is reconstructed (step S385). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to all the transfer source clients or the transfer source clients newly designated in step S385 (step S386). Note that if the transfer source client and transfer destination client cannot be newly specified from a plurality of isolated clients even if the grouping process, the group priority process, the fastest process, or the threshold process is executed in step S385, step S386 is not executed. .

  Thereafter, when the client that has updated the shared data is designated as a new transfer source client in step S385, the server 1 and a new transfer destination client corresponding to the new transfer source client are transferred from the new transfer source client. When the update data is transmitted / transferred and the client that has updated the shared data is designated as a new transfer destination client in step S385, a new transfer source corresponding to the new transfer destination client from the new transfer destination client When the update data is transmitted to the client and the client that has updated the shared data is an isolated client, the updated data is transmitted from the isolated client to the server 1.

  Next, a failure countermeasure process executed by the control unit of the transfer source client when the shared data is updated in the transfer source client and a failure has occurred in the transfer destination client will be described. FIG. 37 is a flowchart for explaining failure countermeasure processing executed by the control unit of the transfer source client when the shared data is updated in the transfer source client and a failure has occurred in the transfer destination client.

  When a command to update shared data is input, the control unit of the transfer source client transmits update data (updated shared data or difference data between shared data before and after update) to the transfer destination client (step S471). At this time, the control unit of the transfer source client counts the number of times of transmission to the transfer destination client and stores it in the RAM. Then, the control unit of the transfer source client starts a timer and determines whether or not a response indicating that update data has been received from the transfer destination client has been received within a predetermined time (step S472). If there is a response indicating that update data has been received from the transfer destination client (step S472: YES), the process is terminated.

  If there is no response indicating that update data has been received from the transfer destination client (step S472: NO), the control unit of the transfer source client counts the number of times the update data has been transmitted and records it in the RAM, and stores the update data a predetermined number of times. It is determined whether or not transmission has been completed (step S473). The predetermined number of times is set in the RAM when the transfer source client is activated. When the number of transmissions is less than the predetermined number (step S473: NO), the control unit of the transfer source client returns the process to step S471. When the number of transmissions is equal to or greater than the predetermined number (step S473: YES), the control unit of the transfer source client transmits information indicating that a failure has occurred in the transfer destination client (transfer destination failure information) to the server 1 (step S47). S474). Then, the control unit of the transfer source client transmits reset information to the transfer destination client, and forcibly disconnects the connection with the transfer destination client (step S475).

  The server 1 that has received the transfer destination failure information executes a deletion process for deleting the information of the transfer destination client in which the failure has occurred from the communication path information table. FIG. 38 is a flowchart for explaining a deletion process executed by the control unit of the server when shared data is updated in the transfer source client and a failure occurs in the transfer destination client.

  The control unit 1a of the server 1 determines whether or not the transfer destination failure information has been received (step S481), and waits until the transfer destination failure information is received (step S481: NO). When the transfer destination failure information is received (step S481: YES), the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table, and deletes the transfer destination client information (step S482). ). At this time, the IP address of the transfer source client is recorded (overwritten) in the transfer destination IP address of the transfer source client, and the transfer source client becomes an isolated client. Then, the control unit 1a of the server 1 determines whether or not there are a plurality of isolated clients (step S483), and when there is a single isolated client (step S483: NO), the process is terminated.

  When there are a plurality of isolated clients (step S483: YES), the control unit 1a of the server 1 executes the above-described grouping processing, group priority processing, fastest processing, threshold processing, or the like between the isolated clients to perform communication. The route information table is reconstructed (step S484). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to all the transfer source clients or the transfer source clients newly designated in step S484 (step S485). If the transfer source client and transfer destination client cannot be newly designated from a plurality of isolated clients even after performing the grouping process, the group priority process, the fastest process, or the threshold process in step S484, step S485 is not executed. .

  When a failure has occurred in the transfer source client to which the server 1 has transmitted the update data, the control unit 1a of the server 1 performs a deletion process for deleting the information of the transfer source client in which the failure has occurred from the communication path information table. Execute. FIG. 39 is a flowchart for explaining a deletion process executed by the control unit of the server when a failure has occurred in the transfer source client to which the server transmitted update data.

  As described in steps S151 to S154, the control unit 1a of the server 1 that has received the update data transmits the update data to the transfer source client (step S571). Then, the control unit 1a of the server 1 activates the timer and determines whether or not a response indicating that the update data has been received from the transfer source client that has transmitted the update data is within a predetermined time (step S572). When there is a response indicating that update data has been received from the transfer source client within a predetermined time (step S572: YES), the control unit 1a of the server 1 ends the process.

  When there is no response indicating that update data has been received from the transfer source client (step S572: NO), the control unit 1a of the server 1 counts the number of times the update data has been transmitted and records it in the RAM, and stores the update data a predetermined number of times. It is determined whether or not transmission has been completed (step S573). The predetermined number of times is set in the RAM when the server 1 is started. When the number of transmissions of the update data is less than the predetermined number (step S573: NO), the control unit 1a of the server 1 returns the process to step S571. When the update data has been transmitted a predetermined number of times or more (step S573: YES), the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table, and deletes information indicating the transfer source client. (Step S574). At this time, the IP address of the transfer destination client is recorded (overwritten) in the transfer destination IP address of the transfer destination client, and the transfer destination client becomes an isolated client. Next, the control unit 1a of the server 1 transmits a command (reset) for forcibly disconnecting the connection with the transfer source client to the transfer destination client corresponding to the transfer source client that does not respond (step S575).

  Then, the control unit 1a of the server 1 determines whether or not there is a response indicating that the connection with the transfer source client has been forcibly disconnected from the transfer destination client (step S576), and waits until there is a response (step S576). : NO). When there is a response from the transfer destination client indicating that the connection with the transfer source client has been forcibly disconnected (step S576: YES), the control unit 1a of the server 1 determines whether or not there are a plurality of isolated clients. If it is determined (step S577) and there is a single isolated client (step S577: NO), the process is terminated.

  When there are a plurality of isolated clients (step S577: YES), the control unit 1a of the server 1 executes the above-described grouping process, group priority process, fastest process, threshold process, and the like between the isolated clients, and performs communication. The route information table is reconstructed (step S578). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to all the transfer source clients or the transfer source clients newly designated in step S578 (step S579). If the transfer source client and transfer destination client cannot be newly designated from a plurality of isolated clients even after performing the grouping process, the group priority process, the fastest process, or the threshold process in step S578, step S579 is not executed. .

  The transfer destination client that has received a command (reset) forcibly disconnecting the connection with the transfer source client by the processing of the server 1 in step S575 executes a disconnection process for forcibly disconnecting the connection with the transfer source client. . FIG. 40 is a flowchart for explaining a disconnection process executed by the control unit of the transfer destination client when a command for forcibly disconnecting the connection with the transfer source client is received.

  The control unit of the transfer destination client determines whether or not a command (reset) for forcibly disconnecting the connection with the transfer source client has been received from the server 1 (step S581), and waits until a reset is received (step S581). S581: NO). When the reset is received (step S581: YES), the control unit of the transfer destination client forcibly disconnects the connection with the transfer source client (step S582), and forces the server 1 to connect with the transfer source client. It responds that it disconnected (step S583).

  When the transfer destination client to which the update data is transferred from the transfer source client has a failure, the control unit 1a of the server 1 deletes the information of the transfer destination client in which the failure has occurred from the communication path information table. Execute the process. FIG. 41 is a flowchart for explaining deletion processing executed by the control unit of the server when a failure has occurred in the transfer destination client to which update data has been transferred from the transfer source client.

  As described in steps S151 to S154, the control unit 1a of the server 1 that has received the update data transmits the update data to the transfer source client (step S671). Then, the control unit 1a of the server 1 determines whether or not there is a response indicating that the update data has been transferred from the transfer source client to the transfer destination client (step S672). When there is a response indicating that update data has been transferred from the transfer source client to the transfer destination client (step S672: YES), the control unit 1a of the server 1 ends the process. When there is no response indicating that update data has been transferred from the transfer source client to the transfer destination client (step S672: NO), the control unit 1a of the server 1 indicates that a failure has occurred in the transfer destination client from the transfer source client. It is determined whether or not the received information (transfer destination failure information) has been received (step S673). When the transfer destination failure information has not been received (step S673: NO), the control unit 1a of the server 1 returns the process to step S672.

  When the transfer destination failure information is received (step S673: YES), the control unit 1a of the server 1 accesses the storage unit 1e, refers to the communication path information table, and deletes the transfer destination client information from the communication path information table. (Step S674). At this time, the IP address of the transfer source client is recorded (overwritten) in the transfer destination IP address of the transfer source client, and the transfer source client becomes an isolated client. Then, the control unit 1a of the server 1 determines whether or not there are a plurality of isolated clients (step S675), and when there is a single isolated client (step S675: NO), the process ends.

  When there are a plurality of isolated clients, the control unit 1a of the server 1 executes the grouping process, the group priority process, the fastest process, or the threshold process described above between the isolated clients to reconstruct the communication path information table. (Step S676). Then, the control unit 1a of the server 1 transmits the transfer destination IP address to all the transfer source clients or the transfer source clients newly designated in step S676 (step S677). If the transfer source client and the transfer destination client cannot be newly designated from a plurality of isolated clients even after performing the grouping process, the group priority process, the fastest process, or the threshold process in step S676, step S677 is not executed. .

  In step S671, the transfer source client that has received the update data transmitted from the server 1 transfers the update data to the transfer destination client. When there is no response indicating that update data has been received from the transfer destination client, the transfer source client executes a disconnection process for forcibly disconnecting the connection with the transfer destination client. FIG. 42 is a flowchart for explaining a disconnection process executed by the control unit of the transfer source client when there is no response indicating that update data has been received from the transfer destination client.

  The control unit of the transfer source client determines whether or not update data is received from the server 1 (step S681), and waits until update data is received from the server 1 (step S681: NO). When the update data is received from the server 1 (step S681: YES), the control unit of the transfer source client transfers the update data to the transfer destination client (step S682). Then, the control unit of the transfer source client starts a timer and determines whether or not a response indicating that update data has been received from the transfer destination client has been received within a predetermined time (step S683). When there is a response indicating that update data has been received from the transfer destination client (step S683: YES), the control unit of the transfer source client ends the process.

  When there is no response indicating that update data has been received from the transfer destination client (step S683: NO), the control unit of the transfer source client counts the number of times the update data has been transferred, records it in the RAM, and stores the update data in a predetermined manner. It is determined whether or not the transfer has been performed more than the number of times (step S684). The predetermined number of times is set in the RAM when the transfer source client is activated. When the transfer count is less than the predetermined count (step S684: NO), the control unit of the transfer source client returns the process to step S682. When the number of transfers is equal to or greater than the predetermined number (step S684: YES), the control unit of the transfer source client transmits information indicating that a failure has occurred in the transfer destination client (transfer destination failure information) to the server 1 (step S684). S685). Then, the control unit of the transfer source client transmits reset information to the transfer destination client and forcibly disconnects the connection with the transfer destination client (step S686).

  In the embodiment, among a plurality of clients connected to the same subnetwork (communication network), one client is designated as a transfer source client, and the other clients are designated as transfer destination clients. Then, the transfer source client that has received the data from the server 1 transfers the data to the transfer destination client. Therefore, even if the system for distributing data becomes large, the system can transmit and transfer data with simple control, efficiently distribute data from the server 1 to the transfer source client, and transfer source client and transfer destination client Data can be transferred quickly without going through a router. Since the data is transferred without going through the router, it is transferred to the transfer destination client in a short time. Since the identification information for identifying the communication network is stored and managed in the server 1, even if the system configuration is changed due to connection / disconnection between the client and the server 1, the transfer source client and the transfer destination client can be easily used. Can be re-specified.

  Also, a transfer source client is specified from among a plurality of clients connected to the server 1, and a client that can communicate with the transfer source client in the fastest time is specified as a transfer destination client. Therefore, even if the system for distributing data is enlarged, the system can transmit and transfer data with simple control, efficiently distribute data from the server 1 to each transfer source client, and transfer source client and transfer destination Data can be transferred quickly between clients. Further, since the communication speed between a plurality of clients connected to the server 1 is stored and managed by the server 1, even if the system configuration is changed due to connection / disconnection of the client and the server 1, the transfer source client In addition, the transfer destination client can be easily specified again.

  When the communication speed between one client connected to the server 1 and another client is faster than a preset threshold, both clients are designated as a transfer source client and a transfer destination client, respectively. Information indicating the transfer destination client is stored in the server 1. Therefore, even if the system for distributing data is enlarged, the system can transmit and transfer data with simple control, efficiently distribute data from the server 1 to each transfer source client, and transfer source client and transfer destination Data can be transferred quickly between clients. Even when a new client connects to the server 1 and the system configuration is changed, the transfer source client and the transfer destination client are re-designated only by comparing the communication speed between the new client and the existing client with a threshold value. Whether the transfer source client and the transfer destination client can be easily specified again.

  When the communication speed between the server 1 and one client is slower than the communication speed between the one client and another client, one client is designated as the transfer destination client, and the other client is designated as the transfer source client. specify. Therefore, even if the system for distributing data is enlarged, the system can transmit and transfer data with simple control, efficiently distribute data from the server 1 to each transfer source client, and transfer source client and transfer destination Data can be transferred quickly between clients. Since the server 1 stores and manages information indicating the transfer source client and the transfer destination client, even if the system configuration is changed due to connection / disconnection between the client and the server 1, the transfer source client and the transfer destination client Clients can be easily redesignated.

  Before transmitting data from the server 1 to the transfer source client, information indicating the transfer destination client is transmitted to the transfer source client, and data can be transmitted / received between the transfer source client and the transfer destination client (connection ). Therefore, the data transmitted from the server 1 to the transfer source client is immediately transferred to the transfer destination client.

  Further, since the above-described connection is established one-to-one between the transfer source client and the transfer destination client, the server 1 designates half of the plurality of clients as the transfer source client and transfers the data to each transfer. Since the distribution to the original client is sufficient, the load on the server 1 is reduced. In addition, data transmission / transfer control of the system is simplified as compared with the case where a one-to-many connection is established between a transfer source client and a transfer destination client.

  In addition, when the connection between the transfer source client and the transfer destination client is disconnected or the transfer source client or the transfer destination client leaves the system and there are a plurality of unestablished connections, the connection is not established. A plurality of clients to be connected are extracted from a plurality of clients, and a connection is established between the extracted clients.

  When the transfer source client cannot receive data, the server 1 causes the transfer destination client that has established a connection with the transfer source client to disconnect the connection. Therefore, the transfer source client that cannot receive data can be excluded from the data distribution system, and the data distribution system can be maintained. Further, by excluding information of the transfer source client that cannot receive data from the communication path information table, a plurality of clients to which a connection should be established is extracted from a plurality of clients that have not yet established a connection, A connection can be established between the extracted clients.

  If the data cannot be received by the transfer destination client, the transfer source client transmits information indicating the transfer destination client that cannot receive the data to the server 1, and Forcibly close the connection established between them. The server 1 that has received the information indicating the transfer destination client that cannot receive the data excludes the information indicating the transfer destination client that cannot receive the data from the communication path information table, so that the connection is not established. A plurality of clients to which a connection should be established can be extracted from the plurality of clients, and a connection can be established between the extracted clients.

  When the client connects to the server 1, that is, when the client enters the data distribution system, information indicating the entered client is added to the communication path information table, and when the client disconnects from the server 1, That is, when the client leaves the system that distributes data, the information indicating the client that has left the room is deleted from the communication path information table, so that the client can be managed smoothly and reliably.

  In the embodiment, the control program is installed in advance in the ROM of the server 1 and the client. However, a configuration in which the control program is installed in the server 1 and the client from a recording medium such as an optical disk or a magnetic disk on which the control program is recorded may be employed. Moreover, the structure which downloads a control program to the server 1 and a client from a communication network via an I / F part may be sufficient.

  Further, in the first embodiment of the selection process by the control unit of the server, the threshold process is performed after the group priority process is performed. However, any one of the processes may be performed. In the second embodiment of the selection process by the control unit of the server, the fastest process is performed after the group priority process is performed, but a configuration in which any one process is performed may be used. Further, the selection process may be performed by appropriately combining the processes constituting the first to third embodiments of the selection process.

  In the embodiment, each client is identified by the IP address. However, when the NAPT (Network Address Port Translation) function is used, the port number is also stored in the communication path information table, and the IP address and Each client may be identified by a combination with a port number. In the embodiment, the transfer source client and the transfer destination client are associated one-to-one. However, a plurality of transfer destination clients are associated with one transfer source client, and a plurality of transfers are performed from one transfer source client. A configuration may be adopted in which data is transferred to the destination client.

  The embodiment described above is an exemplification of matters described in the claims, and various changes can be made within the scope equivalent to the matters described in the claims and the invention described in the claims. it can.

1 server 1a control unit 1b operation unit 1c display unit 1d I / F unit 1e storage unit 11-19 client 11a-19a control unit 11b-19b operation unit 11c-19c display unit 11d-19d I / F unit 11d-19d storage unit 21-25 router 31-33 switch 50 communication network

Claims (23)

In a data distribution system in which a server connected to a plurality of clients via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients.
The server
Means for acquiring identification information for identifying a communication network to which the client is connected;
Means for distinguishing the client for each communication network based on the identification information acquired by the means;
Means for designating a transfer source client for transferring data transmitted from the server and a transfer destination client for receiving the transferred data from a plurality of clients connected to the same communication network distinguished by the means; A data distribution system characterized by comprising: In a data distribution system in which a server connected to a plurality of clients via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients.
Means for measuring a communication speed between the plurality of clients;
The server
Means for designating a transfer source client for transferring data transmitted from the server from a plurality of clients;
A data distribution system comprising: means for designating a transfer destination client having the fastest communication speed with the transfer source client based on the measured communication speed. In a data distribution system in which a server connected to a plurality of clients via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients.
Means for measuring a communication speed between the plurality of clients;
The server
Means for determining whether or not the measured communication speed is equal to or higher than a preset threshold;
When it is determined by the means that the communication speed is equal to or higher than the threshold, both the clients subjected to the determination of the communication speed are transferred from the transfer source client that transfers the data transmitted from the server and the transfer source client. A data distribution system comprising: means for designating a transfer destination client that receives the transferred data. In a data distribution system in which a server connected to a plurality of clients via a communication network distributes data to at least one client, and the data distributed from the server is transferred between the clients.
Means for measuring a first communication speed between the server and one client;
Means for measuring a second communication speed between the one client and another client,
When the measured first communication speed is slower than the second communication speed, the server designates the other client as a transfer source client that transfers data transmitted from the server, and the one client is designated as the first client. A data distribution system comprising means for designating a transfer destination client that receives data transferred from the transfer source client. The server includes means for transmitting information indicating the designated transfer destination client to the transfer source client before transmitting data to the transfer source client;
The transmission / reception enabled state in which data can be transmitted / received between the transfer source client and the transfer destination client is established when the transfer source client receives information indicating the transfer destination client. Item 5. The data distribution system according to any one of Items 1 to 4.   6. The data distribution system according to claim 5, wherein the transmission / reception enabled state is established one-to-one between the transfer source client and the transfer destination client. The server
Means for determining whether or not there are a plurality of the unestablished clients.
Means for designating a client to which the transmission / reception enabled state is to be established among the clients determined to be multiple when it is determined by the means that there are a plurality of the clients whose transmission / reception enabled state is not established; With
The data distribution system according to claim 5 or 6, wherein the transmission / reception enabled state can be established between clients designated by the means. The server
Means for determining whether or not data can be received by the transfer source client;
When the means determines that the data cannot be received by the transfer source client by the means, the transfer destination client that has established the transmit / receive enabled state with the transfer source client that cannot receive the data The data distribution system according to claim 7, further comprising: means for forcibly terminating the transmission / reception enabled state. The transfer source client (or the transfer destination client)
Means for determining whether data can be received at the transfer destination client (or the transfer source client);
The transfer destination client (or the transfer source client) that cannot receive data when it is determined that the transfer destination client (or the transfer source client) cannot receive data. Means for transmitting information to the server;
The method according to claim 7, further comprising: a unit that forcibly terminates the transmission / reception enabled state established with the transfer destination client (or the transfer source client) incapable of receiving data. The data distribution system described. The server
Means for storing information indicating a correspondence between the clients in order to transfer data distributed from the server between the clients;
2. The information processing apparatus according to claim 1, further comprising: means for changing information indicating a correspondence relationship between the clients when the client is connected to the server or the connection between the server and the client is disconnected. The data distribution system according to any one of 9 to 9. In a server in which a plurality of clients are connected via a communication network and deliver data to at least one client,
Means for acquiring identification information for identifying a communication network to which the client is connected when receiving a connection request from the client;
Means for distinguishing the client for each communication network based on the identification information acquired by the means;
Means for designating a transfer source client for transferring data transmitted from the server and a transfer destination client for receiving the transferred data from a plurality of clients connected to the same communication network distinguished by the means; A server characterized by comprising. In a server in which a plurality of clients are connected via a communication network and deliver data to at least one client,
A transfer source client for transferring the data transmitted from the server is designated from among a plurality of clients, and the transfer destination client having the fastest communication speed from the transfer source client is based on the communication speed between the plurality of clients. And a means for designating a server. In a server in which a plurality of clients are connected via a communication network and deliver data to at least one client,
Means for determining whether a communication speed between the plurality of clients is equal to or higher than a preset threshold;
When it is determined by the means that the communication speed is equal to or higher than the threshold, both the clients subjected to the determination of the communication speed are transferred from the transfer source client that transfers the data transmitted from the server and the transfer source client. And means for designating a transfer destination client that receives the transferred data. In a server in which a plurality of clients are connected via a communication network and deliver data to at least one client,
When the communication speed between the server and one client is slower than the communication speed between the one client and another client, the transfer source that transfers data transmitted from the server to the other client A server comprising: a means for designating a client, and designating the one client as a transfer destination client that receives data transferred from the transfer source client. In a data distribution method for transferring data distributed from a server between a plurality of clients connected to the server via a communication network,
The server acquiring identification information identifying a communication network to which the client is connected;
Distinguishing the client for each communication network based on the identification information;
Designating a transfer source client for transferring data transmitted from the server and a transfer destination client for receiving the transferred data from a plurality of clients connected to the same differentiated communication network. A characteristic data distribution method. In a data distribution method for transferring data distributed from a server between a plurality of clients connected to the server,
Measuring a communication speed between the plurality of clients;
Designating a transfer source client for transferring data transmitted from the server from a plurality of clients;
And a step of designating a transfer destination client having the fastest communication speed with the transfer source client based on the measured communication speed. In a data distribution method for transferring data distributed from a server between a plurality of clients connected to the server,
Measuring a communication speed between the plurality of clients;
Determining whether the measured communication speed is equal to or higher than a preset threshold;
When it is determined that the communication speed is equal to or higher than the threshold value, both the clients that are the targets of the communication speed are transferred from the transfer source client that transfers data transmitted from the server and the transfer source client. And a step of designating a transfer destination client that receives data. In a data distribution method for transferring data distributed from a server between a plurality of clients connected to the server,
Measuring a first communication speed between the server and one client;
Measuring a second communication speed between the one client and another client;
When the measured first communication speed is slower than the second communication speed, the other client is designated as a transfer source client for transferring data transmitted from the server, and the one client is designated as the transfer source client. And a step of designating to a transfer destination client that receives the data transferred from the data transfer method. In a computer program for causing a computer to function as a server for distributing data to at least one client when a plurality of clients are connected to the computer via a communication network,
Computer
Means for obtaining identification information for identifying a communication network to which the client is connected;
Based on the identification information acquired by the means, means for distinguishing the client for each communication network and data transmitted from the server from a plurality of clients connected to the same communication network distinguished by the means A computer program which functions as means for designating a transfer source client for transferring and a transfer destination client for receiving transferred data. In a computer program for causing a computer to function as a server for distributing data to at least one client when a plurality of clients are connected to the computer via a communication network,
Computer
Based on the communication speed between the plurality of clients and the means for designating the transfer source client for transferring the data transmitted from the server from among the plurality of clients, the transfer destination having the fastest communication speed from the transfer source client A computer program that functions as a means for specifying a client. In a computer program for causing a computer to function as a server for distributing data to at least one client when a plurality of clients are connected to the computer via a communication network,
Computer
Means for determining whether or not the communication speed between the plurality of clients is equal to or higher than a preset threshold; and when the communication speed is determined to be higher than or equal to the threshold by the means, the determination target of the communication speed A computer program that causes both of the clients to function as a transfer source client that transfers data transmitted from the server and a transfer destination client that receives data transferred from the transfer source client. In a computer program for causing a computer to function as a server for distributing data to at least one client when a plurality of clients are connected to the computer via a communication network,
Computer
When the communication speed between the server and the one client is faster than the communication speed between the one client and another client, the transfer source that transfers the data transmitted from the server to the other client A computer program that designates a client as a means to designate the one client as a transfer destination client that receives data transferred from the transfer source client.   23. A computer-readable recording medium in which the computer program according to any one of claims 19 to 22 is recorded.

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