JP4991151B2 - File transfer system and file transfer method - Google Patents

Description

  The present invention relates to a file transfer system used when transferring a data file via a network, and more particularly to a file transfer system and a file transfer method for transferring a data file according to a transmission band of a communication path. .

  In general, when a data file is transferred between information terminal devices connected by a communication network such as the Internet, if a failure occurs in the communication path (hereinafter referred to as a route) during the data file transfer, it is different from the route. The data file transfer is performed by switching to this route, that is, detouring to another route.

  For example, in order to guarantee communication even when resources for establishing a detour communication route (route) in the network are insufficient, all communication routes established in communication between terminal accommodating units are classified according to their importance. When a detour priority combining the detour attribute and the route state is given and the first communication route between the terminal accommodating units is disconnected by disconnecting the line between the nodes, the detour priority lower than that already established is set. There is one in which the second communication route is stopped and the first communication route is reestablished by a detour route via another node to guarantee communication between terminal accommodating units (Patent Document 1). reference).

  Further, in order to preferentially assign a route (route) with a large available bandwidth to a communication IP packet with a high priority, the available bandwidth related information collecting means can receive a communication IP packet from a terminal device connected to its own router. When receiving, collects the free bandwidth related information of all the routes that the packet can take, stores the collected free bandwidth related information, the route, and the route determination information including the priority of the packet in the route storage unit, and specifies the route When a packet is received from a terminal device connected to its own router, the route determination unit determines the route whose priority is equal to the priority of the packet from the route storage unit and the route matches one of the possible routes of the packet Search for all the information, and find the route with the largest available bandwidth that does not overlap with the route used by other high-priority packets from the route in the route determination information that has been found. There are those to be selected as a route packets (see Patent Document 2).

  Further, in order to facilitate the packet transfer by the router using the second route that is not used except when a failure occurs, a detour setting bit is set in the TOS field in the header information by the packet receiving unit. The IP packet is received, and a routing table in which the highest priority route that can be selected for the packet destination information and the second route (detour route) are associated with the destination information by the routing table creation unit is created and held. The forwarding destination determination unit selects the highest priority route and forwards the received packet when the detour setting bit of the received packet is specified as a value indicating normal route selection based on the routing table, and the detour setting bit is detoured. When a value indicating route selection is specified, there is one that selects a second route and forwards a received packet (see Patent Document 3).

JP-A-9-331322 JP 2001-333100 A JP 2004-249949 A

  In the method described in Patent Document 1 described above, a detour priority combining a detour attribute and a route state is given to a communication route according to its importance, and a detour route is established according to the detour priority. However, no consideration is given to the transmission bandwidth of the detour route and the size of the data file to be transferred. Even if the detour route is established according to the detour priority, the detour route should be transferred with a narrow transmission band. When the data file size is large, the time for occupying the detour route takes a long time, and there is a problem that transfer of another data file is hindered for a long time.

  That is, when a failure occurs in the first route of the wide transmission band (Wide Band), when a data file having a high priority and a large file size is transferred by the second route that is a bypass route If the second route is a narrow transmission band (Narrow Band), it takes a long time to transfer, so other high-priority data files stay in the transfer waiting state, and similarly have a high priority. Other data files cannot be transferred.

  For example, as shown in FIG. 13, when the data file 11 is transferred in the order of the data files 11 to 15 using the second route 10 which is a narrow transmission band, if the data file 11 has a large file size, priority is given. During transfer of the data file 11 of the destination A having a high degree (H), the data file 12 of the destination B having a high priority, the data file 13 having a low priority (L) the destination C, and the destination C having a high priority. The data file 14 and the data file 15 of the destination B having a high priority will stay.

  Furthermore, in the router described in Patent Document 2, when a packet is transmitted, a route having the largest available bandwidth and having no overlapping portion with a route in use by another packet having a higher priority among routes in the route determination information Is selected as the packet route, but simply selecting the route with the largest available bandwidth causes a failure in the first route, which is a high transmission bandwidth, resulting in a narrow transmission bandwidth. When transferring a data file using the second route as a detour, if the file size of the data file being transferred is large, other high-priority data files will remain in the transfer waiting state, giving priority in the same way. There is a problem that it is difficult to eliminate the situation where other high-frequency data files cannot be transferred.

  Also, in the route selection method described in Patent Document 3, when the detour setting bit is designated as a value indicating detour route selection, the second route is selected and the received packet is transferred. In addition, when a data file is transferred using a second route, which is a narrow transmission band, as a result of a failure in the first route, which is a high transmission band, the file size of the data file being transferred is large. Then, there is a problem that it is difficult to eliminate a situation in which another data file with a high priority stays waiting for transfer and similarly, another data file with a high priority cannot be transferred.

  An object of the present invention is to provide a file transfer capable of shortening the waiting time of a high-priority data file when a data file is transferred through a narrow transmission band route when a failure occurs in the wide transmission band route. To obtain a system and a file transfer method.

The present invention is a file transfer system that selectively uses a plurality of communication paths to transfer a data file, and a path management unit that stores a transmission rate measured for each of the communication paths for each of the communication paths; When transferring the data file, the transfer time required to transfer the data file through the selected communication path using one of the communication paths as a selected communication path, and the transmission speed of the selected communication path and File transfer means for dividing the data file and transferring the data file when the transfer time calculated according to the size of the data file exceeds a predetermined time; and the data file is transferred normally If a retransmission is instructed according to the transfer result indicating whether or not the transfer has been performed, and the number of retransmissions exceeds a predetermined allowable transfer count, And a line switching means for switching the communication path based on an instruction from the handling means, wherein the data file includes the data The priority is set for each file, and the handling means uses the detour as a file transfer destination even if the route is detoured based on the transfer result when the priority is high. When it is determined that the connection is not possible, the line switching unit is requested to switch to the detour, and the file transfer unit switches to the detour to be transmitted to different file transfer destinations and transmits the detour. If there are a plurality of the data files, with each their data files perform split, each file after the division, the file A file transfer system, characterized by transferring one by one alternately on the basis of the file transfer destination.

In the file transfer system described above, the present invention further comprises failure / recovery detection means for detecting failure and recovery for each communication path, and the line switching means performs communication according to the detection result of the failure / recovery detection means. It is characterized in that the line is switched.

According to the present invention, in the file transfer system described above, the communication path includes a first path having a wide transmission band and a second path having a narrow transmission band, and the data file is transmitted along the first path. The size of the data file is recorded at the time of the data file transfer, and when a failure in the first route is detected, the route is switched to the second route and transferred according to the size of the data file. Only the remaining part is transferred in the second route except for the finished part.

According to the present invention, in the above-described file transfer system, the communication path includes a first path with a wide transmission band and a second path with a narrow transmission band, and the first path is faulty. The data file is divided and transferred in the second path, and when the data file transfer is detected, the first path is switched to the first path when recovery of the first path is detected. At the time of switching to one route, only the remaining divided portion is transferred on the first route except for the transferred divided portion.

The present invention is also a file transfer method in a file transfer system that selectively uses a plurality of communication paths to transfer a data file, wherein the path management means determines the transmission rate measured for each communication path as the communication speed. Each of the paths is stored, and when the file transfer means transfers the data file, it is a transfer time required for transferring the data file through the selected communication path using one of the communication paths as a selected communication path. The transfer time calculated according to the transmission speed of the selected communication path and the size of the data file exceeds the predetermined time to divide the data file and transfer the data file, The handling means instructs retransmission according to the transfer result indicating whether or not the data file has been transferred normally, and When the number of times exceeds a predetermined allowable number of transfers, the communication path is instructed by using another communication path as a detour, indicating a selected communication path indicating the detour, and the line switching unit is configured to transmit the communication path based on an instruction from the handling unit. The priority is set for each data file in the data file, and when the handling means uses the detour, the priority is high and based on the transfer result, When it is determined that it is not possible to connect to the file transfer destination even if the route is detoured, the line switching unit is requested to switch to the detour, and the file transfer unit continuously transmits to a different file transfer destination. If there are a plurality of the data file to be transmitted is switched to should do the detour is attached to each of those data files perform split, each off after the split Yl is a file transfer method characterized by transferring one by one alternately on the basis of the file transfer destination of the file.

According to the present invention, in the file transfer method described above, the failure / recovery detection unit detects the failure and recovery for each of the communication paths, and the line switching unit is responsive to the detection result of the failure / recovery detection unit. The communication line is switched.

  As described above, according to the present invention, since the data file is divided and transferred according to the transmission band and the line speed, the occupation rate of the communication path can be leveled, and the communication path of the wide transmission band has an obstacle. When the data file is transferred through the communication path of the narrow transmission band, the waiting time of the data file having a high priority can be shortened.

  In the present invention, since the transfer to the detour is performed only when the priority is high when the detour is used and the transfer result is not a predefined error, a data file having a high priority can be transferred according to the priority. effective.

  In the present invention, when it is detected that there is a failure in the first route of the wide transmission band, the data file is divided and transferred on the second route of the narrow transmission band. Can be transferred evenly to the destination.

  In the present invention, when a failure in the first route is detected, only the remaining portion is transferred in the second route except for the transferred portion according to the size of the data file. This reduces the amount of files transferred along the route and reduces the line occupation time.

  In the present invention, if there is a failure in the first route, the data file is divided and transferred in the second route, and when recovery of the first route is detected, the remaining portion is removed except for the transferred divided portion. Since only the divided portion is transferred on the first route, the line occupation time of the second route can be reduced.

  Next, embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, a file transfer system according to an embodiment of the present invention is provided in an information terminal device (hereinafter simply referred to as a terminal) 20, and the terminal 20 is connected to the first and second terminals via routers (not shown). The terminal 20 transfers a data file (hereinafter simply referred to as a file) to the partner terminal using one of the first and second routes. .

  In the illustrated example, the first route has a wide transmission band, the second route has a narrow transmission band, and the second route is used as a bypass. As illustrated, the terminal 20, that is, the file transfer system, includes an information registration unit 21, a line speed measurement unit 22, an information management unit 23, a line switching unit 24, a failure / recovery detection unit 25, a file transfer control unit 26, a file It has a dividing unit 27, a file transfer execution unit 28, a message handling unit (hereinafter simply referred to as a handling unit) 29, and a file assembly unit 30. The counterpart terminal also has the same configuration as the terminal 20.

  The information registration unit 21 provides the user with a GUI (Graphical User Interface) for registering the first and second routes for one destination, and the line speed measurement unit 22 provides a line speed for each route. And the line speed of each route is notified to the information management unit 23. The information management unit 23 manages route information described later for each line, and manages the line speed received from the line speed measurement unit 22.

  The line switching unit 24 switches the line to a normal one of the two routes in accordance with the notification information (failure / recovery information) received from the failure / recovery detection unit 25, and further, the file by the handling unit 29 Perform line switching based on analysis of transfer results. The failure / recovery detection unit 25 uses SNMP (Simple Network Management Protocol), ICMP (Internet Control Message Protocol), or the like to detect a failure or recovery of a route such as a line or various nodes. Is requested, and line switching is requested. The file transfer control unit 26 confirms the transfer file by time activation by Cron (a function for periodically executing commands and programs), generates a message when there is a transfer file, and sends the message to the file transfer execution unit 28. Make a file transfer request. In addition to using Cron, the file transfer control unit 26 may make a file transfer request to the file transfer execution unit 28 using an event such as a file transfer request as a trigger.

  The file division unit 27 collects the destination information from the information management unit 23, and executes file division if the path used for file transfer does not have a sufficient bandwidth for the file capacity. The file transfer execution unit 28 transmits the file requested from the file transfer control unit 26 to the destination collected from the information management unit 23. When the file transfer fails, the handling unit 29 is requested to analyze (analyze), and retransfer is executed according to the result.

  The handling unit 29 analyzes the return message (error / normal) sent back from the other party in response to the file transfer, analyzes whether to perform retransmission and changes the route other than the failure, A switching request is made to the line switching unit 24 according to the analysis result. When the file transferred from the counterpart terminal is divided, the file assembling unit 30 assembles the file and restores the file.

  The information registration unit 21, the line speed measurement unit 22, the information management unit 23, the line switching unit 24, the failure / recovery detection unit 25, the file transfer control unit 26, the file division unit 27, the file transfer execution unit 28, the handling described above. The unit 29 and the file assembly unit 30 may operate on the terminal 20 as, for example, an application program.

  Next, referring to FIG. 2, if the file transfer is performed from the terminal 20 to the partner terminal, the file transfer control unit 26 first confirms the transfer file with respect to the information management unit 23 ( Step S1), destination information (file name, destination address, and transmission band) is obtained from the information management unit 23. Subsequently, the file transfer control unit 26 confirms whether or not the file is divided based on the destination information (step S2).

  Referring to FIG. 3, the information management unit 23 includes a database (storage unit) 31, and file transfer information is stored in the database 31. For example, as the file transfer information, a line speed (transmission speed), a line occupation time (user or maintenance person setting), and whether or not to perform forced division (forced division) are set. The file transfer control unit 26 obtains file transfer information corresponding to the destination address, and first determines whether or not forced division is set (step S3). If forced division is set, file division is determined. A file division request is made to the unit 27 (step S4).

  On the other hand, if the forced division is not set, the file transfer control unit 26 obtains the expected transfer time by the transfer expected time = input file size ÷ transmission speed (step S5), and the expected transfer time ≦ the line occupation time. Then, it is determined that no division is necessary (step S6). Further, if the expected transfer time> the line occupation time, a file division request is made to the file division unit 27 as division necessity (step S7).

  Referring to FIG. 2 again, after that, the file transfer control unit 26 issues a file transfer request to the file transfer execution unit 28, whereby the file transfer execution unit 28 executes the file transfer. At this time, when file division is performed by the file division unit 27, the file transfer execution unit 28 performs file transfer as described later.

  In response to the file transfer, a return message from the counterpart terminal is received as a transmission result by the file transfer execution unit 28 (step S9). When the file transfer execution unit 28 receives the transmission result, it requests the handling unit 29 to analyze the transmission result. That is, it is requested whether or not there was an error. Referring to FIG. 4, in error analysis (step S <b> 10), first, the handling unit 29 determines a detour according to the transfer result correspondence table stored in the storage unit 32 held by the handling unit 29. In addition, an allowable transfer count is set in the storage unit 32 in advance, and the transfer count of the file is incremented each time transfer is performed.

  The handling unit 29 determines an error state according to the destination and the transmission result (step S10), and determines subsequent processing from the transfer result correspondence table. That is, the route detour result is obtained from the transfer result correspondence table, and it is determined whether the route detour result indicates retry (target) or route detour (step S11). For example, if the transfer count related to the file is less than the allowable transfer count, the route detour result indicates a retry (step S12), and if the transfer count reaches the allowable transfer count, the route detour result indicates a route detour.

If the route detour result indicates route detour, the handling unit 29 determines the priority of the file (step S13). If the priority is low ( L ), the process is terminated (step S14). On the other hand, when the priority is high (H), the handling unit 29 determines whether or not to execute the route detour (step S15). If step S15 to your information, the transmission result is fixed error value (server failure, etc.), it is determined that even if the route bypassing is not possible connections. For example, it is determined whether or not to perform retransmission on the detour according to the code shown in FIG. 5 (in FIG. 5, ◯ indicates that retransmission is performed).

  If it is determined in step S15 that there is an abnormality, the handling unit 29 registers a route abnormality in the line switching unit 24 (step S16), and the process ends (step S17). On the other hand, if it determines with it being normal, since the handling part 29 will perform a route detour, it notifies the line switching part 24 to that effect (step S18).

  When line switching (route bypass) is determined as described above, a switching request is notified from the handling unit 29 to the line switching unit 24, and the switching request is transmitted from the line switching unit 24 to the information management unit 23. . The line switching unit 24 executes line switching. Referring to FIG. 6, the line switching unit 24 performs line state management according to the failure / recovery information from the failure / recovery detection unit 25 (step S19), and the built-in storage unit 33 supports the address (route address). In addition, the line status (normal / abnormal) is managed.

  Then, the line state is obtained from the storage unit 33 according to the route address, and compared with the line state for each route address given from the failure / recovery detection unit 25, the line state of the input address (route address) is changed. (Step S20). Subsequently, the corresponding route address selection change of the information management unit 23 is performed (step S21), and the line state of the input address is changed according to the line state of each route address given from the handling unit 29 ( Step S22), the corresponding route address selection of the information management unit 23 is changed (Step S23).

  Referring to FIG. 7, the information management unit 23 performs destination information management (step S24), and the built-in storage unit 31 uses the file name, priority, destination address, first route address, It manages the transmission band, its line state (normal / abnormal), the second route address, its transmission band, and its line state (normal / abnormal). As described above, the file transfer control unit 26 sends the destination address. When there is an acquisition request (destination information collection) (step S25), the destination information is obtained from the storage unit 34, the line state is determined, and the route with the normal line state and its transmission band are returned to the file transfer control unit 26. (Step S26).

  As shown in FIG. 2, when performing retransmission due to an error (NG), the file transfer control unit 26 obtains destination information (file name, destination address, and transmission band) from the information management unit 23 again, and A file transmission request is made to the file transfer execution unit 28.

  As shown in FIG. 8A, when the files 71 to 75 are sequentially sent to the destinations A to C using the first route (the files 71, 72, 74, and 75 have high priority (H). The file 73 has a low priority (L), and the file 71 has a large file size). For example, a failure occurs in the first route, and the second route When the files 71 to 75 are transferred using the file 71, the file 71 has a large file size, so the file transfer to the destination A occupies the line. On the other hand, as described above, when the file 71 is divided into the files 71-1 to 71-3 and the priority is taken into consideration, as shown in FIG. By performing the transfer, it is possible to prevent a situation in which the file transfer to the destination A occupies the line.

  By the way, in the electronic data interchange (EDI) using the Internet, the above-described priority level is assigned to each file, and a high-priority file (for example, an ordering / ordering file) is another file. Unlike, it needs to be processed quickly. However, the file size may reach several MB at the maximum, and if a transfer is made using a narrow transmission band route at a base (terminal) connected to a plurality of bases (terminals), the number of the paths will be several. It becomes a situation where time is occupied, and communication with other bases becomes virtually impossible.

  For example, as shown in FIG. 9, when transferring different files 41 to 43 to the sites A to C, the files 41 to 43 can be transferred in a short time by using the first route of the wide transmission band. However, if a failure occurs in the first route and the second route with a narrow transmission band is used, it takes time to transfer the file 41, and the waiting time of the files 41 and 43 becomes extremely long. End up.

  For this reason, as described above, the file 41 is divided into the files 41-1 and 42-2, and the file 42 is similarly divided into the files 42-1 and 42-2. Further, the file 43 is divided into files 43-1 and 43-2, and as shown in FIG. 9, the files 41-1, 42-1, 43-1, 41-2, 42-2, and 43-2. If the file transfer is performed evenly in this order, the file transfer to the bases B and C can be performed without waiting for a long time.

  Furthermore, if a failure occurs in the first path during file transfer in the first path of the wide transmission band, for example, as shown in FIG. If a failure occurs in this route, the entire file must be transferred again using the second route, including the transferred portion, which takes a long time to transfer and is extremely inefficient.

  Therefore, as shown in FIG. 10, even when file transfer is performed in the first route, if the file 41 is divided into files 44-1 to 44-6 and transferred, the first method is transferred during transfer. Even if a failure occurs in the path, the transferred files (for example, the files 44-1 to 44-4) do not need to be transferred in the second path, and the remaining files (file 44- in the second path). 5 and 44-6) need only be transferred, and transfer can be performed in a short time even using the second route.

  Note that when a failure occurs in the first route during file transfer in the first route of the wide transmission band, for example, immediately before the end of file transmission, as shown in FIG. If a failure occurs in the first route, the entire file must be transferred again using the second route, including the transferred portion, which takes a long time and is extremely inefficient. is there.

  For this reason, when the first route is used, the information management unit 23 records and transfers the file size. When a failure occurs in the first route, the line speed and the file size are referred to. Thus, only the remaining file 52 except the transferred file 51 may be transferred in the second route.

  When a failure occurs in the first route, as shown in FIG. 12, the files 61-1 and 61-2, 62-1 and 62-2, and files to be sent to the bases A to C are respectively shown. If it divides | segments into 63-1 and 63-2 and it sends by the 2nd route, since the 2nd route is a narrow transmission band, communication cost will start.

  For this reason, when the failure / recovery detection unit 25 detects the restoration of the first route, the line switching unit 24 switches to the first route, and the files transferred up to now (for example, the transferred files 61-1 and 61 Except for 62-1), the remaining files 63-1, 61-2, 62-2, and 63-2 may be transferred in the first route.

  In this way, when performing file transfer, if the file is divided according to the transmission band and the file transfer is performed according to the priority, the first route of the wide transmission band cannot be used due to a failure. Even in this case, all the files can be transferred uniformly by using the second route, and a situation where the files stay (that is, a situation where the files cannot be transferred for a long time) can be avoided.

  As is clear from the above description, the information registration unit 21, the line speed measurement unit 22, the information management unit 23, the file transfer control unit 26, the file division unit 27, and the file transfer execution unit 28 collectively perform path management. It functions as a means and a file transfer means.

  Since the data file is divided and transferred according to the transmission band and the line speed, the occupation rate of the communication path can be leveled, so that the present invention can be applied to a network system for effectively using the communication path.

It is a functional block diagram for demonstrating the function of the file transfer system by embodiment of this invention. It is a flowchart for demonstrating the file transfer operation | movement of the file transfer system shown in FIG. It is a flowchart for demonstrating the function of the file transfer control part shown in FIG. It is a flowchart for demonstrating the function of the message handling part shown in FIG. It is a figure which shows the list of transfer result codes. It is a flowchart for demonstrating the function of the line switching part shown in FIG. It is a flowchart for demonstrating the function of the information management part shown in FIG. It is a figure which shows an example of file transfer, (a) is a figure which shows file transfer using a 1st path | route, (b) is a figure which shows file transfer using a 2nd path | route. It is a figure for demonstrating the example of the file transfer at the time of switching from the 1st path | route of a wide transmission band to the 2nd path | route of a narrow transmission band. It is a figure for demonstrating the 1st example which performs file transfer by the 2nd path | route of a narrow transmission band when a failure generate | occur | produces in the 1st path | route of a wide transmission band. It is a figure for demonstrating the 2nd example which performs file transfer by the 2nd path | route of a narrow transmission band when a failure generate | occur | produces in the 1st path | route of a wide transmission band. It is a figure for demonstrating the example of the file transfer at the time of the 1st path | route of a wide transmission band recovering during the file transfer in the 2nd path | route of a narrow transmission band. It is a figure for demonstrating the conventional file transfer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Terminal device 21 Information registration part 22 Line speed measurement part 23 Information management part 24 Line switching part 25 Failure / restoration detection part 26 File transfer control part 27 File division part 28 File transfer execution part 29 Message handling part 30 File assembly part

Claims (6)

A file transfer system for transferring data files selectively using a plurality of communication paths,
Path management means for storing the transmission rate measured for each communication path for each of the communication paths;
When transferring the data file, the transfer time required to transfer the data file through the selected communication path using one of the communication paths as a selected communication path, and the transmission speed of the selected communication path and File transfer means for dividing the data file and transferring the data file when a transfer time calculated according to the size of the data file exceeds a predetermined time;
When the retransmission is instructed according to the transfer result indicating whether or not the data file has been transferred normally and the number of retransmissions exceeds a predetermined allowable transfer count, the other communication path is used as a bypass. Handling means for indicating a selected communication path indicating
Line switching means for switching the communication path based on an instruction from the handling means,
The data file has its priority set for each data file,
When the handling means uses the detour, when the priority is high and it is determined that the file transfer destination cannot be connected even if the route is detoured based on the transfer result, Request the line switching means to switch to a detour,
It said file transfer means, when a plurality of said data file to be transmitted is switched to a different file transfer destination continues the detour to be transmitted is about the their respective data files perform split, after the split file transfer system, wherein the transfer of each file, one by one alternately on the basis of the file transfer destination of the file. A failure / recovery detecting means for detecting the failure and recovery for each communication path;
2. The file transfer system according to claim 1, wherein the line switching unit switches the communication line in accordance with a detection result of the failure / recovery detection unit. The communication path has a first path of a wide transmission band and a second path of a narrow transmission band,
Transferring the data file in the first path;
Record the size of the data file when transferring the data file,
If a failure in the first route is detected, switch to the second route,
3. The file transfer system according to claim 2, wherein only the remaining part is transferred in the second path except for the transferred part according to the size of the data file. The communication path has a first path of a wide transmission band and a second path of a narrow transmission band,
When there is a failure in the first route, the data file is divided and transferred in the second route,
During the data file transfer, if recovery of the first path is detected, the first path is switched,
3. The file transfer system according to claim 2, wherein at the time of switching to the first route, only the remaining divided portion is transferred on the first route except for the transferred divided portion. A file transfer method in a file transfer system that selectively uses a plurality of communication paths to transfer a data file,
The path management means stores the transmission rate measured for each communication path for each of the communication paths,
When the file transfer means transfers the data file, a transfer time required for transferring the data file through the selected communication path using one of the communication paths as a selected communication path, the selected communication path When the transfer time calculated according to the transmission speed and the size of the data file exceeds a predetermined time, the data file is divided to transfer the data file,
When the handling means instructs retransmission according to the transfer result indicating whether or not the data file has been transferred normally, and the number of retransmissions exceeds a predetermined allowable transfer count, another communication path is bypassed. Indicating the selected communication path indicating the detour as
Line switching means switches the communication path based on an instruction from the handling means,
The data file has its priority set for each data file,
When the handling means uses the detour, when the priority is high and it is determined that the file transfer destination cannot be connected even if the route is detoured based on the transfer result, Request the line switching means to switch to a detour,
It said file transfer means, when a plurality of said data file to be transmitted is switched to a different file transfer destination continues the detour to be transmitted is about the their respective data files perform split, after the split each file, the file transfer method characterized by transferring one by one alternately on the basis of the file transfer destination of the file. Failure / recovery detection means detects the failure and recovery for each communication path,
The file transfer method according to claim 5, wherein the line switching unit switches a communication line according to a detection result of the failure / recovery detection unit.

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