JP2011060078A - File distribution system, file distribution method and monitored device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce loads of file distribution to a plurality of monitored devices without adding any function to a monitoring device. <P>SOLUTION: The monitoring device 131 transmits a file distribution request message to monitored devices 133 to which a file is distributed. When receiving the file distribution request message, the first monitored device 133a which can communicate with the monitoring device through a path bypassing the other monitored devices, acquires a designated file from a designated distribution server 132. When receiving a file distribution request message to the other monitored device 133b, the first monitored device 133a rewrites the information of the distribution server in the received file distribution request message as the information of the first monitored device 133a, and transfers the rewritten information. The monitored device 133b to which the transferred file distribution request message is to be distributed, acquires the designated file from the first monitored device 133a which is the designated distribution server according to the received file distribution request message. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a file distribution system, and in particular, a file distribution request message is transmitted from a monitoring apparatus to a monitored apparatus, and the monitored apparatus that has received the file distribution request message sends a file from a distribution server specified in the message. The present invention relates to a file distribution system to be acquired.

  A first related technique relating to the present invention is shown in FIG. In the file distribution system shown in FIG. 17, a monitoring device 131 and a file distribution server 132 are connected to a router 136 constituting a relay network 137. Of the plurality of monitored devices 133a ′ to 133d ′, the monitored device 133a ′ and the monitored device 133d ′ are connected to the relay network 137 through the upper connection line 135a and the upper connection line 135b. Further, the monitored device 133a ′ and the monitored device 133b ′ are connected by an interconnection line 134a, and the monitored device 133b ′ and the monitored device 133c ′ are connected by an interconnection line 134b, and the monitored device 133c ′ is connected. The monitored device 133d ′ is connected by an interconnection line 134c.

  The monitoring device 131, the file distribution server 132, the plurality of monitored devices 133a ′ to 133d ′, and the relay network 137 are connected to each other by a standard network protocol such as IP (Internet Protocol). Secured.

  In the file distribution system having such a network configuration, when file distribution is performed to the monitored devices 133a ′ to 133d ′ under the control of the monitoring device 131, first, the monitored devices 133a ′ to 133d are transmitted from the monitoring device 131. A file delivery request message is sent to '. Here, the file distribution request message includes the identifier of the monitored device to be distributed (monitored device name), the identifier of the distribution target file (file name), and the identifier of the file distribution server 132 (distribution server name). ing.

  The file distribution request message transmitted from the monitoring device 131 to each of the monitored devices 133a ′ to 133d ′ is sent to either the upper connection line 135a or the upper connection line 135b via the router 136 and the relay network 137. Sent out. Which line is sent depends on route information on the relay network 137. Here, it is assumed that the message is sent to the upper connection line 135a.

  The file delivery request message addressed to the monitored device 133a ′ sent to the upper connection line 135a is received by the monitored device 133a ′. Further, the file delivery request message addressed to the monitored device 133b ′ sent to the upper connection line 135a is relayed by the monitored device 133a ′ and received by the monitored device 133b ′. Further, the file delivery request message addressed to the monitored device 133c ′ sent to the upper connection line 135a is relayed by the monitored devices 133a ′ and 133b ′ and received by the monitored device 133c ′. The file delivery request message addressed to the monitored device 133d ′ sent to the upper connection line 135a is relayed by the monitored devices 133a ′ to 133c ′ and received by the monitored device 133d ′.

  The monitored devices 133a ′ to 133d ′ have a configuration as shown in FIG. The plurality of external connection ports 112a to 112e are ports for connecting the own device 133 ′ to other devices. The monitored device 133 ′ determines whether the message input from the external connection port 112 is set to the own device or the destination other than the own device, and if it is the former, the message is received by the own device. In the latter case, the message is transferred to the appropriate external connection port 112 corresponding to the destination. Since such a function is based on a standardized method, detailed description thereof is omitted.

  The monitored device 133 ′ includes a file acquisition unit 115 ′ that acquires a file from a file distribution server connected via the external connection port 112, and a file storage unit 117 ′ that stores the acquired file. .

  The monitored device 133a ′ that has received the file distribution message addressed to itself requests the file acquisition unit 115 ′ to acquire the file specified by the message from the file distribution server 132 specified by the file distribution message. To do. This file acquisition request is delivered to the file distribution server 132 through the upper connection line 135a connected to the external connection port, the relay network 137, and the router 136. The file distribution server 132 analyzes this file acquisition request and transmits the requested file to the requesting monitored device 133a ′. The transmitted file is delivered to the monitored device 133a ′ through the router 136, the relay network 137, and the upper connection line 135a. The file acquisition unit 115 ′ of the monitored device 133a ′ stores the received file in the file storage unit 117 ′.

  Other monitored devices 133b ′ to 133d ′ also transmit a file acquisition request to the file distribution server 132 in the same manner as the monitored device 133a ′. At this time, the file acquisition request transmitted from the monitored device 133b ′ is delivered to the file distribution server 132 through the monitored device 133a ′, the upper connection line 135a, the relay network 137, and the router 136. The file acquisition request transmitted from the monitored device 133c ′ is delivered to the file distribution server 132 through the monitored devices 133b and 133a ′, the upper connection line 135a, the relay network 137, and the router 136. The file acquisition request transmitted from the monitored device 133d ′ is delivered to the file distribution server 132 through the monitored devices 133c ′, 133b ′, 133a ′, the upper connection line 135a, the relay network 137, and the router 136.

  The file distribution server 132 that has received these file acquisition requests transmits the requested file to the request-target monitored devices 133b ′ to 133d ′. At this time, the file transmitted to the monitored device 133b ′ is delivered to the monitored device 133b ′ through the router 136, the relay network 137, the upper connection line 135a, and the monitored device 133a ′. The file transmitted to the monitored device 133c ′ is delivered to the monitored device 133c ′ through the router 136, the relay network 137, the upper connection line 135a ′, the monitored device 133a ′, and the monitored device 133b ′. The file transmitted to the monitored device 133d ′ is delivered to the monitored device 133d ′ through the router 136, the relay network 137, the upper connection line 135a ′, the monitored device 133b ′, and the monitored device 133c ′.

  On the other hand, Patent Document 1 discloses a second related technique related to the present invention. In the second related technology, a file distribution server, a transfer management server (corresponding to a monitoring device in the first related technology), and a plurality of clients (corresponding to monitored devices in the first related technology) are connected via a network. In the systems connected to each other, the transfer management server performs control to distribute the file distribution sources. Specifically, the transfer management server determines this client as a distribution source if there is another client that has already received the same file distribution by the file distribution server, and if there is no such client, The file distribution server is determined as the distribution source.

JP 2007-228558 A

  According to the first related technology described above, since all of the monitored devices 133a ′ to 133d ′ send a file acquisition request to the file distribution server 132, a large load is applied to the file distribution server 132, and a relay network is used. The amount of data flowing through 137 and the upper connection line 135a increases.

  On the other hand, according to the second related technique described above, the file distribution sources are distributed, so the load on the file distribution server can be reduced. However, in order to apply the second related technology to the first related technology, the file distribution source is determined in consideration of the presence / absence of the monitored device that has already received the same file and the connection relationship of the monitored device. The control function to be determined needs to be implemented in the monitoring device 131.

  The present invention has been proposed in view of such circumstances, and the object thereof is a file distribution system that solves the problem that a function addition to a monitoring device is required in order to distribute file distribution sources, The object is to provide a file distribution method, a monitored apparatus, and a program thereof.

A file distribution system according to one aspect of the present invention is:
A plurality of monitored devices;
And a monitoring device that transmits a file delivery request message to the plurality of monitored devices.
The plurality of monitored devices communicate with the monitoring device through a path that passes through the first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device, and through a route that passes through the other monitored device. Consisting of two monitored devices,
The first monitored device is:
File acquisition means for acquiring and storing a specified file from a specified distribution server according to the file distribution request message when the file distribution request message is received;
A message editing / re-sending unit that, when receiving a file delivery request message addressed to another monitored device, rewrites the information of the delivery server in the received file delivery request message to the information of the own device and transfers it;
When receiving a file acquisition request addressed to its own device, it comprises a file distribution means for transmitting the corresponding file stored in the own device to the request source,
The second monitored device is:
When receiving a file distribution request message addressed to its own device, the apparatus includes file acquisition means for acquiring a specified file from a specified distribution server according to the file distribution request message.

In addition, a file distribution system according to another aspect of the present invention is
A plurality of monitored devices;
And a monitoring device that transmits a file delivery request message to the plurality of monitored devices.
The plurality of monitored devices communicate with the monitoring device through a path that passes through the first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device, and through a route that passes through the other monitored device. Consisting of two monitored devices,
The first monitored device is:
File acquisition means for acquiring and storing a specified file from a specified distribution server according to the file distribution request message when the file distribution request message is received;
When a plurality of file delivery request messages related to the same file addressed to another monitored device are received, a redistribution execution monitored device that redistributes the file from the plurality of other monitored devices, and the redistribution Redistribution selection means for determining a redistribution target monitored device that distributes a file from an execution monitored device;
Redistribution validation message processing means for transmitting a redistribution validation message in which the device is designated as the file delivery server to the redelivery execution monitored device;
Among a plurality of file distribution request messages related to the same file addressed to the other monitored device, a message for rewriting and transferring the information of the distribution server in the file distribution request message other than the address to be monitored for redistribution to the information of the own device Editing and re-sending means;
When receiving a file acquisition request addressed to its own device, it comprises a file distribution means for transmitting the corresponding file stored in the own device to the request source,
The second monitored device is:
A file acquisition means for acquiring a specified file from a specified distribution server according to the file distribution request message and the redistribution validation message when receiving a file delivery request message and a redelivery validation message addressed to the own device;
When a redistribution validation message addressed to the own device is received, a file delivery request specifying the own device as a delivery server for the designated file is directed to the designated redistribution target monitored device according to the redelivery validation message Redelivery validation message processing means for transmitting a message.

In addition, a file delivery method according to another aspect of the present invention is
(A) The monitoring device transmits a file distribution request message to the monitored device to be distributed,
(B) When the first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device receives the file distribution request message, the designated file is specified according to the file distribution request message. Obtained from the distribution server
(C) When the first monitored apparatus receives a file distribution request message addressed to another monitored apparatus, the information of the distribution server in the received file distribution request message is rewritten to the information of the own apparatus and transferred,
(D) The first monitored device in which the second monitored device that is the destination of the transferred file delivery request message is the delivery server that designates the designated file in accordance with the received file delivery request message. Get from the device,
It has the structure of.

In addition, a file delivery method according to another aspect of the present invention is
(A) The monitoring device transmits a plurality of file distribution request messages related to the same file to a plurality of monitored devices to be distributed.
(B) A first monitored device that can communicate with the monitoring device through a route that does not go through another monitored device is directed to a file distribution request message addressed to the same device and to a plurality of other monitored devices. When the file delivery request message is received, the designated file is acquired from the designated delivery server according to the file delivery request message,
(C) Redistribution execution in which the first monitored device redistributes a file from the first monitored devices when the plurality of other monitored devices are the second monitored devices. A monitored device and a redistribution target monitored device that distributes a file from the redistribution execution monitored device are determined, and the second monitored device determined as the redistribution execution monitored device A re-distribution validation message specifying the device as the file distribution server is transmitted, and the distribution server information is rewritten to the information of the own device for the second monitored device other than the re-distribution target monitored device. Forward the file delivery request message,
(D) The second monitored device determined as the redistribution execution monitored device that has received the redistribution validation message addressed to its own device has designated the designated file in accordance with the redistribution validation message A file distribution request message is transmitted from the distribution server to the second monitored device determined as the redistribution target monitored device, with the device as the distribution server,
(E) The second monitored device that has received the file delivery request message addressed to itself acquires the designated file from the designated delivery server in accordance with the file delivery request message.
The structure is taken.

Moreover, the monitored apparatus which is the other form of this invention is
When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a file delivery request message addressed to another monitored device is received through the line, message editing / re-sending means for rewriting and transferring the delivery server information in the received file delivery request message to the own device information;
And a file distribution means for transmitting a corresponding file stored in the own apparatus to a request source when a file acquisition request addressed to the own apparatus is received through a line connected to another monitored apparatus.

Moreover, the monitored apparatus which is the other form of this invention is
When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a plurality of file delivery request messages addressed to other monitored devices related to the same file as the file are received through the line, a redistribution execution target that performs redistribution of the file from the other monitored devices is provided. Determine a monitoring device and a redistribution target monitored device that distributes a file from the redistribution execution monitored device, and determine the own device with respect to the other monitored device determined as the redistribution execution monitored device A file distribution request in which the re-distribution validation message specified to the distribution server of the file is transmitted, and the information of the distribution server is rewritten to the information of the own apparatus to a monitored apparatus other than the monitored apparatus to be re-distributed A means of forwarding messages;
And a file distribution means for transmitting a corresponding file stored in the own apparatus to a request source when a file acquisition request addressed to the own apparatus is received through a line connected to another monitored apparatus.

Moreover, the program which is the other form of this invention is:
Computer
When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a file delivery request message addressed to another monitored device is received through the line, message editing / re-sending means for rewriting and transferring the delivery server information in the received file delivery request message to the own device information;
When a file acquisition request addressed to itself is received through a line connected to another monitored device, it functions as a file distribution means for transmitting the corresponding file stored in the device to the request source.

Moreover, the program which is the other form of this invention is:
Computer
When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a plurality of file delivery request messages addressed to other monitored devices related to the same file as the file are received through the line, a redistribution execution target that performs redistribution of the file from the other monitored devices is provided. Determine a monitoring device and a redistribution target monitored device that distributes a file from the redistribution execution monitored device, and determine the own device with respect to the other monitored device determined as the redistribution execution monitored device A file distribution request in which the re-distribution validation message specified to the distribution server of the file is transmitted, and the information of the distribution server is rewritten to the information of the own apparatus to a monitored apparatus other than the monitored apparatus to be re-distributed A means of forwarding messages;
When a file acquisition request addressed to itself is received through a line connected to another monitored device, it functions as a file distribution means for transmitting the corresponding file stored in the device to the request source.

  According to the present invention, file distribution sources can be distributed without adding a new function to the monitoring apparatus.

It is a block diagram of the file delivery system concerning a 1st embodiment of the present invention. It is a block diagram of the monitored apparatus in the 1st embodiment of the present invention. It is a flowchart which shows the process example of the to-be-monitored apparatus in the 1st Embodiment of this invention. It is a figure which shows a mode that the monitoring apparatus transmits several file delivery request messages in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows operation | movement when the to-be-monitored apparatus receives the file delivery request message addressed to an own apparatus in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows operation | movement when the to-be-monitored apparatus transmits a file acquisition request in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows operation | movement when the to-be-monitored apparatus acquires a file in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows operation | movement when the to-be-monitored apparatus receives the file delivery request message addressed to another apparatus in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows the operation | movement at the time of the monitored apparatus rewriting and relaying the file delivery request message addressed to another apparatus in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows operation | movement when the to-be-monitored apparatus receives the file acquisition request from another to-be-monitored apparatus in the file delivery system which concerns on the 1st Embodiment of this invention. It is a figure which shows a mode that a file is delivered from the to-be-monitored apparatus to another to-be-monitored apparatus in the file delivery system which concerns on the 1st Embodiment of this invention. It is a block diagram of the file delivery system which concerns on the 2nd Embodiment of this invention. It is a block diagram of the to-be-monitored apparatus in the 2nd Embodiment of this invention. It is a flowchart which shows the process example of the to-be-monitored apparatus in the 2nd Embodiment of this invention. It is a flowchart which shows the process example of the to-be-monitored apparatus in the 2nd Embodiment of this invention. It is a figure which shows a mode that a file is delivered from the to-be-monitored apparatus to another to-be-monitored apparatus in the file delivery system which concerns on the 2nd Embodiment of this invention. [BRIEF DESCRIPTION OF THE DRAWINGS] It is a block diagram of the file delivery system by the 1st related technique relevant to this invention. It is a block diagram of the monitored apparatus in the file delivery system by the 1st related technique relevant to this invention. It is a figure which shows the file delivery condition in the file delivery system by the 1st related technique relevant to this invention.

[First embodiment]
Referring to FIG. 1, the file distribution system according to the first embodiment of the present invention includes a monitoring device 131, a file distribution server 132, and a relay including a router 136 to which the monitoring device 131 and the file distribution server 132 are connected. A network 137, a monitored device 133a connected to the relay network 137 through a higher-level connection line 135a, a monitored device 133b connected to the monitored device 133a through an interconnection line 134a, and the monitored device 133b A monitored device 133c connected through the connection line 134b, and a monitored device 133d connected to the monitored device 133c through the interconnection line 134c and connected to the relay network 137 through the upper connection line 135d. .

  The relay network 137, the monitoring device 131, the file distribution server 132, and the plurality of monitored devices 133a to 133d are connected to be communicable with each other by a standard network protocol such as IP.

  The monitoring device 131 is a computer having a function of managing file distribution to a plurality of monitored devices 133a to 133d. When the monitoring device 131 performs file distribution to each of the monitored devices 133a to 133d, the monitoring device 131 individually transmits a file distribution request message to each of the monitored devices 133a to 133d. The file distribution request message includes a monitored device identifier (monitored device name) that uniquely identifies a target monitored device, a distribution file identifier (file name) that uniquely identifies a file to be distributed, and a unique file distribution source. Includes a distribution server identifier (distribution server name).

  The file distribution server 132 is a computer that includes a storage device that holds files to be distributed. When the file distribution server 132 receives a file distribution request including a distribution file name, the file distribution server 132 has a function of reading out the distribution file specified by the distribution file name from the storage device and transmitting it to the distribution request source.

  Each of the monitored devices 133a to 133d is a computer including a storage device that holds a distributed file. An example of the monitored devices 133a to 133d is shown in FIG.

  Referring to FIG. 2, the monitored device 133 has a plurality of external connection ports 112a to 112e for connecting the device itself to other devices. The monitored device 133 judges whether the message input from the external connection port 112 is the own device or a destination other than the own device, and if it is the former, the message is received by the own device. In the latter case, the message is transferred to the appropriate external connection port 112 according to the destination. Since such a function is based on a standardized method, detailed description thereof is omitted.

  Further, the monitored device 133 edits the extracted file distribution request message and sends it from the external connection port 112 with the message extraction unit 113 having a function of extracting the file distribution request message input from the external connection port 112. The message editing / retransmission unit 114, the file acquisition unit 115 that acquires a file from the distribution server connected via the external connection port 112, the file storage unit 117 that stores the acquired file in the storage device, and the file A storage file list 118 that is management information of files stored in the storage unit 117 is provided. The stored file list 118 records the distribution file name and the state of the file (during acquisition, already acquired).

  FIG. 3 is a flowchart showing the operation of the monitored device 133. Hereinafter, with reference to FIG. 2 and FIG. 3, functions and operations of each unit of the monitored device 133 will be described.

  The monitored device 133 extracts, in the message extraction unit 113, the file distribution request message addressed to the own device and the file distribution request message addressed to the other device via the own device input from the external connection port 112 (S101). . At this time, the message extraction unit 113 extracts only the file distribution request message addressed to the own device and addressed to the other device, which is input from the external connection port 112 to which a preset type of line is connected. Specifically, only the file distribution request message addressed to the own device and other devices input from the external connection port 112 connected to the upper connection line is extracted. Alternatively, the message extraction unit 113 extracts only the file delivery request message addressed to the own device and other devices input from the external connection port 112 set in advance as a port for message extraction.

  The message extraction unit 113 analyzes the extracted file distribution request message, acquires a distribution server name and a distribution file name from the message, searches the storage file list 118 using the acquired distribution file name as a key, and the same It is investigated whether the distribution file name is recorded in the storage file list 118 (S102).

  If the same distribution file name is not recorded in the storage file list 118 as a result of the investigation, the message extraction unit 113 notifies the file acquisition unit 115 of the acquired distribution server name and distribution file name. The file acquisition unit 115 registers the notified distribution file name in the storage file list 118, sets the status to “acquiring” (S103), and then notifies the file with the notified distribution file name from the notified distribution server. Obtain (S104). Specifically, the distribution server with the notified distribution server name is the destination, the own device is the request source, and a file acquisition request including the notified distribution file name is transmitted from the external connection port 112 leading to the distribution server. In response to this file acquisition request, it waits for the delivery file transmitted from the delivery server to be received. When the distribution file is received, the file acquisition unit 115 stores the received distribution file in the file storage unit 117 and displays the status corresponding to the file name of the distribution file recorded in the storage file list 118 as “acquired”. (S105). Then, the monitored device 133 proceeds to the process of step S108.

  On the other hand, if the same distribution file name is recorded in the storage file list 118 as a result of the investigation, the message extraction unit 113 determines whether the status of the file is “acquired” (S106). If it has been acquired, the monitored device 133 proceeds to the process of step S108. If it is not already acquired but is being acquired, the monitored device 133 waits until the state of the file is already acquired. Then, when the file acquisition unit 115 receives the distribution file and stores it in the file storage unit 117, and when the state of the file in the storage file list 118 is already acquired, the process proceeds to step S108.

  In step S108, the monitored device 133 determines whether the file distribution request message extracted this time in step S101 is a message addressed to itself. If it is a file delivery request message addressed to its own apparatus, the processing in FIG. If the file distribution request message is not addressed to the own device but to another device, the monitored device 133 uses the message editing / retransmission unit 114 to specify the distribution server name in the file distribution request message extracted this time. The name is rewritten and sent to the external connection port leading to the destination (S109). Then, the process of FIG. 3 is finished.

  The re-sent file delivery request message is delivered to the destination monitored device 133. In the destination monitored device 133, the file acquisition unit 115 requests the distribution server with the file distribution name specified in the received file distribution message to acquire the file with the distribution file name specified in the message. As described above, since the distribution server name in the file distribution request message is rewritten to the identification name of the monitored device 133 that has edited the message, the file acquisition request is addressed to the monitored device 133 that has performed the message editing. Sent to. The file delivery unit 116 of the monitored device 133 that has edited the message receives this file acquisition request message, reads the requested delivery file from the file storage unit 117, and transmits it to the requested monitored device 133.

  Next, the overall operation of the file distribution system according to the present embodiment will be described.

  When the file A is distributed to the monitored devices 133a to 133d under the control of the monitoring device 131, the monitoring device 131 first sends a file to each monitored device 133a to 133d as shown in FIG. Distribution request messages 151a to 151d are individually transmitted. Here, the file distribution request messages 151a to 151d include an identifier of the monitored device 133 to be distributed (monitored device name), an identifier of the distribution target file (file name), and an identifier of the file distribution server 132 (distribution server name). )It is included. The sending order of the plurality of messages 151a to 151d is arbitrary. Here, it is assumed that the messages are transmitted in the order of 151a, 151b, 151c, and 151d.

  The file delivery request messages 151a to 151d transmitted from the monitoring device 131 to the respective monitored devices 133a to 133d are sent via the router 136 and the relay network 137 to either the upper connection line 135a or the upper connection line 135b. Is sent out. Which line is sent depends on route information on the relay network 137. Here, assuming that the file delivery request messages 151a, 151b, 151c, and 151d are sent to the upper connection line 135a in this order, the messages arrive at the monitored device 133a in that order.

  As shown in FIG. 5, the monitored device 133a receives the file distribution request message 151a through the external connection port 112 connected to the upper connection line 135a. When the monitored device 133a receives the subsequent file distribution request messages 151b to 151d, the monitored device 133a sets the processes in a standby state, and performs the processing in the order of reception as soon as the processing of the previously received file distribution request message 151a is completed.

  First, the message extraction unit 113 of the monitored device 133a extracts the file distribution request message 151a, and checks whether or not the distribution file name specified by the extracted message is recorded in the storage file list 118 (FIG. 5 in process 161). Assuming that no distribution file name is recorded in the stored file list 118 as shown in FIG. 5, the message extraction unit 113 requests the file acquisition unit 115 to acquire the file A.

  As shown in FIG. 6, the file acquisition unit 115 registers the distribution file name in the extracted message in the storage file list 118, sets the status to “acquiring”, and uses the extracted message A file acquisition request including the distribution file name is transmitted to the file distribution server 132 which is the designated distribution server (process 163 in FIG. 6). Since the file acquisition request 151a processed this time is addressed to its own apparatus, the monitored apparatus 133a ends the processing of FIG. 3 relating to the file acquisition request 151a.

  The file acquisition request is delivered to the file distribution server 132 through the upper connection line 135a, the relay network 137, and the router 136. In accordance with the received file acquisition request, the file distribution server 132 transmits the requested distribution file A to the requesting monitored device 133a. The transmitted distribution file A is delivered to the monitored device 133a through the router 136, the relay network 137, and the upper connection line 135a. When the file acquisition unit 115 of the monitored device 133a receives the distribution file A from the file distribution server 132, the file acquisition unit 115 stores the distribution file A in the file storage unit 117 and updates the state of the file in the storage file list 118 to “acquired” (FIG. 7 processing 164).

  When the monitored device 133a finishes the processing of FIG. 3 related to the file acquisition request 151a, the monitored device 133a starts the processing of the next file acquisition request 151b.

  The message extraction unit 113 of the monitored device 133a extracts the file distribution request message 151b, and confirms whether or not the distribution file name specified by the extracted message is recorded in the storage file list 118. In this case, the file A is already recorded in the stored file list 118 as shown in FIG. 8 by the above-described processing of the file distribution request message 151a received earlier. Accordingly, the monitored device 133a checks the state of the file A, and immediately waits for “acquired” until it becomes “acquired” if it is “acquiring”, and then edits and retransmits the message 114 Process by. That is, as shown in FIG. 9, the message editing / retransmission unit 114 rewrites the distribution server name in the file distribution request message 151b with the name of its own device 133a, and connects to the external connection port 112 connected to the interconnection line 134a. To send.

  The file delivery request message 151b is delivered to the destination monitored device 133b through the interconnection line 134a. When the monitored device 133b receives this file distribution request message 151b, the file acquisition unit 115 confirms that the file name A is not recorded in the storage file list 118, and is designated as a distribution server by the file distribution message 151b. The monitored device 133a is requested to acquire the file A specified by the message. This file acquisition request is delivered to the destination monitored device 133a through the interconnection line 134a.

  As shown in FIG. 10, the monitored device 133a analyzes the file acquisition request by the file distribution unit 116, reads the requested file A from the file storage unit 117, and transmits it to the requested monitored device 133b. To do. The transmitted file A is delivered to the monitored device 133b through the interconnection line 134a. The file acquisition unit 115 of the monitored device 133b stores the received file A in the file storage unit 117, and updates the state of the file name in the storage file list 118 to acquired.

  The remaining file delivery messages 151c and 151d are processed in the same manner as the file delivery message 151b. As a result, the file A is distributed to the monitored devices 133c and 133d by using the monitored device 133a as a distribution server.

  As described above, according to the present embodiment, the file delivery request message specifying the file delivery server 132 as the delivery server and the file A as the delivery file for each of the monitored devices 133a to 133d from the monitoring device 131. Is transmitted to the monitored device 133a from the file distribution server 132, but the monitored devices 133b, 133c, and 133d are monitored by the monitored device 133a as shown in FIG. File A is distributed as a distribution server. As a result, the load on the file distribution server 132 is reduced, and an increase in the amount of data due to the same file flowing over and over the relay network 137 and the upper connection line 135a is suppressed.

  Further, since the monitored device 133a connected to the upper connection line 135a automatically acts as a distribution server by detecting a file acquisition request message addressed to another monitored device via its own device, the file distribution source Therefore, it is not necessary to add a new function to the monitoring device 131 in order to distribute.

[Second Embodiment]
Referring to FIG. 12, the file distribution system according to the second embodiment of the present invention is compared with the file distribution system according to the first embodiment shown in FIG. Instead, the only difference is that the monitored devices 138a to 138d are provided.

  Referring to FIG. 13, the monitored device 138 has a network topology management unit 161, a redistribution device selection unit 162, and a redistribution validation compared with the monitored device 133 in the first embodiment shown in FIG. The difference is that a message processing unit 163 is newly added. The functions of the message editing / retransmission unit 114 and the file acquisition unit 115 are partially different from those of the first embodiment.

  The network topology management unit 161 holds network topology information configured by interconnection lines between monitored devices 138. Specifically, in the case of the network of FIG. 12, the monitored device 138a and the monitored device 138b are connected by the interconnection line 134a, and the monitored device 138b and the monitored device 138c are connected by the interconnection line 134b. It is recorded in the topology information that they are connected and that the monitored device 138c and the monitored device 138d are connected by the interconnection line 134c.

  Here, when the network is configured using a standard protocol such as IP, the network topology management unit 161 may use a routing table constructed by a routing protocol defined as the standard.

  The redistribution device selection unit 162 receives all the file distribution request messages extracted by the message extraction unit 113, and obtains the network topology information for each of a plurality of file distribution request messages addressed to other devices having the same distribution target file name. Referring to the function of determining one or more other monitored devices that are redistribution execution devices and one or more monitored devices (redistribution target devices) that redistribute files from the redistribution execution devices. Have. The determination criterion is arbitrary, but it is desirable to determine the redistribution execution apparatus and the redistribution target apparatus so that the redistribution path of the file is the shortest.

  The redistribution validation message processing unit 163 uses the redistribution device selection unit 162 as a redistribution execution device to another monitored device, the distribution file name to be redistributed, and the own device name as the identifier of the distribution server And a monitored device name as a redistribution target device, and has a function of transmitting a redistribution validation message instructing validation of the redistribution function.

  In addition, when the redistribution validation message processing unit 163 receives the redistribution validation message addressed to itself from another monitored device, the redelivery validation message processing unit 163 is designated as the target of redistribution by the redistribution validation message. The device has a function of transmitting a file distribution request message including the monitored device name, the distribution target file name, and the own device name as an identifier of the distribution server to the device. Further, the redistribution validation message processing unit 163 transmits the redistribution validation message addressed to itself received from another monitored device to the file acquisition unit 115.

  If the same file name as the distribution target file name specified in the redistribution activation message is not recorded in the storage file list 118, the file acquisition unit 115 sends the file acquisition unit 115 to the distribution server specified in the redistribution activation message. Then, a file acquisition request for requesting the distribution target file is transmitted, and the distribution target file acquired thereby is stored in the file storage unit 117.

  Further, the message editing / retransmission unit 114, among the plurality of file distribution request messages addressed to other apparatuses having the same distribution target file name, determines the target of the distribution target determined to distribute the file from the redistribution execution apparatus. For file delivery request messages other than those addressed to the monitoring device, rewrite the file delivery server name included in the message to its own device name and relay it. For file delivery request messages destined for the redistributed monitored device, relay processing is not performed. Discard. Since the monitored device selected as the redistribution execution device acquires the redistribution target file upon reception of the above redistribution validation message, the file distribution request addressed to the monitored device selected as the redistribution execution device Messages may also be discarded without being relayed.

  14 and 15 are flowcharts showing the operation of the monitored apparatus 138. Hereinafter, the function and operation of each unit of the monitored apparatus 138 will be described with reference to FIGS.

  In the message extraction unit 113, the monitored apparatus 138 extracts the file distribution request message addressed to the own apparatus input from the external connection port 112 and the file distribution request message addressed to the other apparatus via the own apparatus (S201). . At this time, the message extraction unit 113 extracts only the file distribution request message addressed to the own device and addressed to the other device, which is input from the external connection port 112 to which a preset type of line is connected. Specifically, only the file distribution request message addressed to the own device and other devices input from the external connection port 112 connected to the upper connection line is extracted. Alternatively, the message extraction unit 113 extracts only the file delivery request message addressed to the own device and other devices input from the external connection port 112 set in advance as a port for message extraction.

  Further, when the message extraction unit 113 extracts a plurality of file distribution request messages (file distribution request messages addressed to the own device or file distribution request messages addressed to other devices via the own device) from the external connection port 112, Processing is started for one and the rest is in a standby state. The processing order may be the extraction order (reception order), and if the file delivery request message addressed to the own device is included, the file delivery request message addressed to the own device is processed with priority. Also good.

  The message extraction unit 113 analyzes the extracted file distribution request message, acquires a distribution server name and a distribution file name from the message, searches the storage file list 118 using the acquired distribution file name as a key, and the same It is checked whether the distribution file name is recorded in the storage file list 118 (S202).

  If the same distribution file name is not recorded in the storage file list 118 as a result of the investigation, the message extraction unit 113 notifies the file acquisition unit 115 of the acquired distribution server name and distribution file name. The file acquisition unit 115 registers the notified distribution file name in the storage file list 118, sets the status to “acquiring” (S203), and then notifies the file with the notified distribution file name from the notified distribution server. Obtain (S204). Specifically, the distribution server with the notified distribution server name is the destination, the own device is the request source, and a file acquisition request including the notified distribution file name is transmitted from the external connection port 112 leading to the distribution server. In response to this file acquisition request, it waits for the delivery file transmitted from the delivery server to be received. When the distribution file is received, the file acquisition unit 115 stores the received distribution file in the file storage unit 117 and displays the status corresponding to the file name of the distribution file recorded in the storage file list 118 as “acquired”. (S205). Then, the monitored device 138 proceeds to the process of step S208.

  On the other hand, if the same distribution file name is recorded in the storage file list 118 as a result of the investigation, the message extraction unit 113 determines whether the state of the file is “acquired” (S206). If it has been acquired, the monitored apparatus 138 proceeds to the process of step S208. If it is not acquired but is being acquired, the monitored device 138 waits until the status of the file becomes acquired. Then, when the file acquisition unit 115 receives the distribution file and stores it in the file storage unit 117, and when the state of the file in the storage file list 118 is already acquired, the process proceeds to step S208.

  In step S208, the monitored device 138 determines whether there are a plurality of file delivery request messages addressed to other waiting devices that specify the same delivery file. If there are no such multiple file delivery request messages, the same operation as in the first embodiment is performed. That is, the monitored device 138 determines whether or not the file delivery request message extracted this time in step S201 is a message addressed to itself, and if it is a file delivery request message addressed to itself, FIG. And the process of FIG. 15 is finished. If the file delivery request message is not addressed to the own device but directed to another device, the monitored device 138 uses the message editing / retransmission unit 114 to specify the name of the delivery server in the file delivery request message extracted this time. The name is rewritten and sent to the external connection port leading to the destination (S213). Then, the processes in FIGS. 14 and 15 are finished.

  The re-sent file delivery request message is delivered to the destination monitored device 138. In the destination monitored device 138, the file acquisition unit 115 requests the distribution server specified by the received file distribution message to acquire the file specified by the message. As described above, the distribution server name in the file distribution request message is rewritten to the identification name of the monitored device 138 that has edited the message, so that the file acquisition request is addressed to the monitored device 138 that has performed the message editing. Sent to. The file delivery unit 116 of the monitored device 138 that has edited the message receives this file acquisition request message, reads the requested delivery file from the file storage unit 117, and transmits it to the requested monitored device 138.

  On the other hand, if it is determined in step S208 that there are a plurality of file delivery request messages addressed to other devices that are on standby specifying the same delivery file, the redistribution device selection unit 162 refers to the network topology information and waits for them. Among the destination devices of the file distribution request message in the middle, a monitored device to be a redistribution execution device and a monitored device to be redistributed to be redistributed from the redistribution execution device are selected (S209). Next, the redistribution validation message processing unit 163 transmits a redistribution validation message to the monitored apparatus selected as the redistribution execution apparatus (S210). Further, the message editing / retransmission unit 114 rewrites the distribution server name in the waiting file distribution request message destined for a device other than the monitored device to be redistributed with the own device name and retransmits it (S211). Then, the processes in FIGS. 14 and 15 are finished.

  Next, the overall operation of the file distribution system according to the present embodiment will be described.

  When the file A is distributed to the monitored devices 138a to 138d under the control of the monitoring device 131, the monitoring device 131 first has the respective monitored devices 138a as in FIG. 4 of the first embodiment. File delivery request messages 151a to 151d are individually transmitted to .about.138d. Here, the file distribution request messages 151 a to 151 d include the identifier of the monitored device 138 to be distributed, the identifier of the distribution target file, and the identifier of the file distribution server 132. As for the order of sending out the plurality of messages 151a to 151d, it is desirable to send the monitored device 138 connected to the upper connection line first. Here, it is assumed that the messages are sent in the order of 151a, 151d, 151b, and 151c.

  The file distribution request messages 151a to 151d transmitted from the monitoring device 131 to the respective monitored devices 138a to 138d are sent to either the upper connection line 135a or the upper connection line 135b via the router 136 and the relay network 137. Is sent out. Which line is sent depends on route information on the relay network 137. Here, assuming that the file delivery request messages 151a, 151d, 151b, and 151c are sent to the upper connection line 135a in this order, they arrive at the monitored device 138a in that order.

  When the monitored device 138a extracts the file delivery request message 151a (S201), the monitored device 138a places the subsequent file delivery request messages 151b to 151d in a standby state. The monitored apparatus 138a performs the same processing as the steps S102 to S107 of FIG. 3 in the first embodiment on the extracted file distribution request 151a (S202 to S207 of FIG. 14).

  Next, since there are a plurality of file delivery request messages 151b to 151d addressed to other waiting apparatuses that designate the same delivery file A (S208), the monitored device 138a performs processing by the redistribution device selection unit 162 (S208). S209). Specifically, the redistribution apparatus selection unit 162 refers to the network topology information, and the file redistribution path is the shortest among the destination apparatuses 138b to 138d of the waiting file distribution request messages 151b to 151d. In this manner, a monitored device to be a redistribution execution device and a monitored device to be redistributed to be redistributed from the redistribution execution device are selected.

  In this case, for example, as shown in FIG. 16, if the monitored device 138c is a redistribution execution device and the monitored device 138d is a redistribution target to be redistributed from the monitored device 138c, the monitored device 138a The total distance of the route through which the file is distributed to the monitored devices 138b, 138c, and 138d is 1 + 2 + 1 = 4, for example, where the distance connected by one interconnection line is 1, and is the shortest.

  Next, the redistribution validation message processing unit 163 transmits a redistribution validation message to the monitored apparatus 138c selected as the redistribution execution apparatus (S210). In addition, the message editing / retransmission unit 114 rewrites the distribution server in the waiting file distribution request messages 151b and 151c destined for a device other than the monitored device 138d, which is a redistribution target device, to its own device and retransmits it ( S211).

  Upon receiving the redistribution validation message or file delivery request message from the monitored device 138a, the monitored device 138c obtains the file A from the monitored device 138a, which is the delivery server specified by the message, in the file acquisition unit 115. To start. Further, the monitored apparatus 138c transmits, in the redistribution validation message processing unit 163, a file distribution acquisition message in which its own apparatus is designated as the distribution server of file A to the monitored apparatus 138d. The monitored device 138d that has received this file distribution acquisition message acquires a file from the monitored device 138c, which is the distribution server specified by the message. On the other hand, the monitored device 138b receives the file delivery request message 151b, and acquires a file from the monitored device 138a that is the delivery server designated by the message.

  As described above, according to the present embodiment, the file delivery request message specifying the file delivery server 132 as the delivery server and the file A as the delivery file is sent from the monitoring device 131 to each of the monitored devices 138a to 138d. Is transmitted from the file distribution server 132 for the monitored device 138a, but the monitored device 138a is a distribution server for the monitored devices 138b and 138c as shown in FIG. The file A is distributed and the monitored device 138d is distributed as the monitored device 138c as a distribution server. As a result, the load on the file distribution server 132 is reduced, and an increase in the amount of data due to the same file flowing over and over the relay network 137 and the upper connection line 135a is suppressed. Furthermore, since the file redistribution process can be distributed in addition to the monitored device 138a arranged at the boundary with the relay network, it is possible to avoid the concentration of the load on a specific monitored device.

  In addition, one or more other monitored devices serving as a redistribution execution device and one or more redistribution targets to be redistributed from the redistribution execution device so that the file redistribution path is the shortest. Since the device is determined, it is possible to shorten the time required to finish distributing the file to all monitored devices.

  Also, the monitored device 138 connected to the upper connection line automatically acts as a distribution server by detecting a file acquisition request message addressed to another monitored device via its own device, and enables redistribution. Therefore, it is not necessary to add a new function to the monitoring device 131 in order to distribute the file distribution sources.

  In the above description, only one monitored device that performs file redistribution is selected. However, depending on the number of monitored devices requested at the same time, file redistribution is enabled in a plurality of monitored devices. Also good.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various other additions and modifications can be made. In addition, the monitored apparatus of the present invention can be realized by a computer and a program as well as by realizing the functions of the monitored apparatus in hardware. The program is provided by being recorded on a computer-readable recording medium such as a magnetic disk or a semiconductor memory, and is read by the computer at the time of starting up the computer, etc. It is made to function as a monitored apparatus in the form.

113 Message Extraction Unit 114 Message Editing / Retransmission Unit 115 File Acquisition Unit 116 File Distribution Unit 117 File Storage Unit 118 Stored File List 131 Monitoring Device 132 File Distribution Server 133 Monitored Device 136 Router 137 Relay Network 138 Monitored Device 161 Network Topology Management unit 162 Redistribution device selection unit 163 Redistribution validation message processing unit

Claims (11)

A plurality of monitored devices;
A monitoring device that transmits a file delivery request message to the plurality of monitored devices,
The plurality of monitored devices communicate with the monitoring device through a route that passes through the first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device, and through a route that passes through the other monitored device. Consisting of two monitored devices,
The first monitored device is:
File acquisition means for acquiring and storing a specified file from a specified distribution server according to the file distribution request message when the file distribution request message is received;
A message editing / re-sending unit that, when receiving a file delivery request message addressed to another monitored device, rewrites the information of the delivery server in the received file delivery request message to the information of the own device and transfers it;
When receiving a file acquisition request addressed to its own device, it comprises a file distribution means for transmitting the corresponding file stored in the own device to the request source,
The second monitored device is:
A file distribution system comprising file acquisition means for acquiring a specified file from a specified distribution server in accordance with the file distribution request message when a file distribution request message addressed to the own apparatus is received. A plurality of monitored devices;
A monitoring device that transmits a file delivery request message to the plurality of monitored devices,
The plurality of monitored devices communicate with the monitoring device through a route that passes through the first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device, and through a route that passes through the other monitored device. Consisting of two monitored devices,
The first monitored device is:
File acquisition means for acquiring and storing a specified file from a specified distribution server according to the file distribution request message when the file distribution request message is received;
When a plurality of file delivery request messages related to the same file addressed to another monitored device are received, a redistribution execution monitored device that redistributes the file from the plurality of other monitored devices, and the redistribution Redistribution selection means for determining a redistribution target monitored device that distributes a file from an execution monitored device;
Redistribution validation message processing means for transmitting a redistribution validation message in which the device is designated as the file delivery server to the redelivery execution monitored device;
Among a plurality of file delivery request messages related to the same file addressed to the other monitored device, a message for rewriting and transferring the information of the delivery server in the file delivery request message other than the address to the monitored device to be redistributed with the information of the own device Editing and re-sending means;
When receiving a file acquisition request addressed to its own device, it comprises a file distribution means for transmitting the corresponding file stored in the own device to the request source,
The second monitored device is:
A file acquisition means for acquiring a specified file from a specified distribution server according to the file distribution request message and the redistribution validation message when receiving a file delivery request message and a redelivery validation message addressed to the own device;
When a redistribution validation message addressed to the own device is received, a file delivery request specifying the own device as a delivery server for the designated file is directed to the designated redistribution target monitored device according to the redelivery validation message A file delivery system comprising redelivery validation message processing means for transmitting a message. The first monitored device is:
Network topology management means for holding network topology information of monitored devices,
The redistribution device selection unit refers to the network topology information, and determines a redistribution execution monitored device and a redistribution target monitored device so that a file redistribution path is the shortest. The file delivery system according to claim 2.   The monitored apparatus includes a plurality of external connection ports for connecting to a line, and the monitored apparatus in which a higher-level connection line is connected to any one of the plurality of external connection ports is the first 4. The device according to claim 1, wherein the monitored device that operates as a monitored device and has no upper connection line connected to any port operates as the second monitored device. 5. The file distribution system described in 1.   5. The file distribution system according to claim 1, wherein the upper connection line is connected to the monitoring device through a relay network. (A) The monitoring device transmits a file distribution request message to the monitored device to be distributed,
(B) When the first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device receives the file delivery request message, the designated file is designated according to the file delivery request message. Obtained from the distribution server
(C) When the first monitored device receives a file distribution request message addressed to another monitored device, the information of the distribution server in the received file distribution request message is rewritten to the information of the own device and transferred,
(D) The first monitored device in which the second monitored device that is the destination of the transferred file delivery request message is the delivery server that designates the designated file in accordance with the received file delivery request message. Get from the device,
A file delivery method characterized by the above. (A) The monitoring device transmits a plurality of file distribution request messages related to the same file to a plurality of monitored devices to be distributed.
(B) A first monitored device that can communicate with the monitoring device through a route that does not pass through another monitored device is directed to a file delivery request message addressed to the same device related to the same file and a plurality of other monitored devices. When the file delivery request message is received, the designated file is acquired from the designated delivery server according to the file delivery request message,
(C) When the first monitored device sets the plurality of other monitored devices as second monitored devices, redistribution execution is performed to redistribute files from the first monitored devices. A monitored device and a redistribution target monitored device that distributes a file from the redistribution execution monitored device are determined, and the second monitored device determined as the redistribution execution monitored device A re-distribution validation message specifying the device as the file distribution server is transmitted, and the distribution server information is rewritten to the information of the own device for the second monitored device other than the re-distribution target monitored device Forward the file delivery request message,
(D) The second monitored device determined as the redistribution execution monitored device that has received the redistribution validation message addressed to its own device has designated the designated file in accordance with the redistribution validation message A file distribution request message is transmitted from the distribution server to the second monitored device determined as the redistribution target monitored device, with the device as the distribution server,
(E) The second monitored device that has received the file delivery request message addressed to itself acquires the designated file from the designated delivery server in accordance with the file delivery request message.
A file delivery method characterized by the above. When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a file delivery request message addressed to another monitored device is received through the line, message editing / re-sending means for rewriting and transferring the delivery server information in the received file delivery request message to the own device information;
And a file distribution means for transmitting a corresponding file stored in the own device to a request source when a file acquisition request addressed to the own device is received through a line connected to another monitored device. apparatus. When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a plurality of file delivery request messages addressed to another monitored device related to the same file as the file are received through the line, a redistribution execution target that performs redistribution of the file from the plurality of other monitored devices is received. A monitoring device and a redistribution target monitored device that distributes a file from the redistribution execution monitored device are determined, and the own device is assigned to the other monitored device determined as the redistribution execution monitored device. A file distribution request in which a re-distribution validation message designated to the file distribution server is transmitted, and the information of the distribution server is rewritten with the information of the own apparatus to a monitored apparatus other than the monitored apparatus to be re-distributed A means of forwarding messages;
And a file distribution means for transmitting a corresponding file stored in the own device to a request source when a file acquisition request addressed to the own device is received through a line connected to another monitored device. apparatus. Computer
When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a file delivery request message addressed to another monitored device is received through the line, message editing / re-sending means for rewriting and transferring the delivery server information in the received file delivery request message to the own device information;
A program for functioning as a file distribution means for transmitting a corresponding file stored in a local device to a request source when a file acquisition request addressed to the local device is received through a line connected to another monitored device. Computer
When a file distribution request message is received through a line that can communicate with the monitoring apparatus through a route that does not pass through another monitored apparatus, the specified file is acquired from the specified distribution server and stored in accordance with the file distribution request message. A file acquisition means;
When a plurality of file delivery request messages addressed to another monitored device related to the same file as the file are received through the line, a redistribution execution target that performs redistribution of the file from the plurality of other monitored devices is received. A monitoring device and a redistribution target monitored device that distributes a file from the redistribution execution monitored device are determined, and the own device is assigned to the other monitored device determined as the redistribution execution monitored device. A file distribution request in which a re-distribution validation message designated to the file distribution server is transmitted, and the information of the distribution server is rewritten with the information of the own apparatus to a monitored apparatus other than the monitored apparatus to be re-distributed A means of forwarding messages;
A program for functioning as a file distribution means for transmitting a corresponding file stored in a local device to a request source when a file acquisition request addressed to the local device is received through a line connected to another monitored device.

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