JP2015122697A - Redundant transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission system whose reliability in data transmission is improved when redundant transmission is performed.SOLUTION: A redundant transmission system comprises: a transmission side device that is able to transmit a transmission object data string to a communication network capable of providing a plurality of communication routes while giving each of the data string a sequence number in an at least duplicate state taking different links and different communication routes toward an opposite device; and a receiving side device that includes a buffer region corresponding to each of the sequence numbers, performs buffer processing of each piece of data transmitted by the opposite device through different communication routes in the communication network in the buffer regions by associating it to the respective sequence numbers, monitors a state of the links and/or communication routes on the basis of a reception state of a route which each piece of data having the same contents went through, and that is able to perform restoration processing of the transmission object data string transmitted in the at least duplicate state by taking out each piece of data buffered in the buffer region in the sequence number order.

Description

  The present invention relates to a communication system in which data strings transferred between devices have redundancy, and more particularly to a fault-tolerant transmission system using a communication network that can take a plurality of communication paths.

  As a transmission system for transferring a data string between a transmission side device and a reception side device, there is a communication system in which reliability is ensured by making a device configuration and a communication path redundant.

  In such a conventional communication system (redundant transmission system), a combination of a transmission circuit (system 0) and a reception circuit (system 0) and a combination of a transmission circuit (system 1) and a reception circuit (system 1) are equivalent. The transmission unit and the reception unit are provided in a redundant configuration and are duplicated. There are also a transmission system having two systems, an active system and a standby system, and a transmission system in which the active system and the standby system have an N + 1 configuration. In such a transmission system, when a failure occurs in any part of the system, the system related to the failure point is switched to the standby system without interruption. This system switching is performed on a system-by-system basis.

  Related techniques are described in Patent Documents 1 to 4, for example. These documents describe uninterruptible switching means for switching a plurality of systems without data loss.

  Further, Patent Document 5 describes a prior art in which the above-described reliability is ensured by a different approach. In this prior art, the transmission side device and the reception side device are connected by a communication network that can take a plurality of communication paths, and the reception device side discards unnecessary packets and arranges packets while performing duplex transmission for each packet. The system for carrying out the repair is disclosed. More specifically, the transmission side device copies each packet in two and sends it to the reception side device through a plurality of paths, and the reception side device identifies the packet based on a time stamp or a hash value and copies the plurality of packets. One packet is left and the other is discarded.

JP 2002-344432 A JP 2002-026855 A JP 2005-109848 A JP 2012-070352 A JP 2006-174406 A

  FIG. 11 shows a processing concept of a transmission method using a duplexed transmission path that performs non-instantaneous switching from the active system to the standby system when a system failure occurs.

In the duplex transmission system shown in the figure, when transmitting frame data between a transmission device and a reception device, a combination of a transmission circuit (system 0) and a reception circuit (system 0) between systems 0, transmission circuit (system 1) and reception The circuit (1 system) is duplicated by a combination of one system. When a failure occurs in any of the duplexed systems, the duplexed transmission system determines whether the failure location is a location related to the 0 system or a location related to the 1 system, and performs switching on a system basis. To work.
At this time, the system in which the failure has occurred is disconnected. As a result, the system is out of the duplex state and is operated as a single system.

  In other words, although redundancy as a transmission system is useful for system failure, if a failure occurs in any part of the remaining system, a conduction path cannot be secured and communication is interrupted. . That is, when a double failure occurs, communication is adversely affected.

As an example, FIG. 12 shows a transition when the 0 system fails. Further, FIG. 13 shows a state in which the remaining transmission circuits have failed in this state. Both figures show a case where one receiving circuit of the receiving device fails and the other transmitting circuit of the transmitting device fails.
When a failure of one system is detected for the first time, the system selection control unit of the receiving apparatus discriminates the failure of the receiving circuit (0 system) and selects the receiving system (1 system) as the operating system. An instruction is issued to the selection circuit. The selection circuit instructed for the system operates to switch the selection system to the first system and deliver the frame data via the first system route to the subsequent stage. As a result, the 0-system transmission line including the failed receiving circuit (0-system) is disconnected.
If the transmitter circuit (system 1) of the transmitter further fails in this state, the remaining system 1 transmission line will also be interrupted due to the failure of the transmitter circuit (system 1). As a result, neither system can be operated, and a transmission path cannot be secured.

  In addition, in the prior art disclosed in Patent Document 5, although reliability on the communication path can be improved, for each system failure of the transmission side device or the reception side device, exclusion for each system is performed in the same manner as in the above technique. Is called.

  Further, another problem can be found in the literature transmission system as described above. Although there is a minor failure or failure that cannot be identified as a transmission path failure, the transmission path system switching is not performed, but intermittent loss or discard of transfer data seems to occur continuously. There is room for improvement in measures in such cases. In such a case, it is possible to identify part of the transfer data that has not been reached by data confirmation after receiving the transfer data, and perform system switching or transfer data retransmission request processing. However, it can be a problem in data communications that require low delay and continuity.

  In other words, the existing transmission system has room for improvement in redundancy configuration and reliability.

  In view of the above problems, an object of the present invention is to provide a transmission system that further increases the reliability of data transmission.

  The redundant transmission system according to the present invention takes a plurality of communication paths for a data string to be transmitted, taking a different communication path from a different system while assigning a sequence number to each of the data strings, at least in a duplex state with the partner apparatus. Each of the data transmitted from the partner device through a different communication path of the communication network having a buffer area corresponding to each of the sequence numbers and a transmission side device capable of being sent to the communication network to be obtained. While the buffer processing is performed corresponding to each sequence number in the area, the status of the system and / or communication path is monitored based on the reception status of the path through which each data of the same content passes, and is buffered in the buffer area By extracting each piece of data in order of sequence number, a data string that is a transmission target that has been transmitted in at least a duplex state is obtained. And having a receiving-side apparatus is capable source process.

  In the redundant transmission method according to the present invention, the transmission side apparatus takes a plurality of communication paths from different systems while assigning a sequence number to each data sequence to be transmitted, at least in a duplex state with the other apparatus, The receiving side device has a buffer area corresponding to each sequence number, and each data transmitted from the partner device through a different communication route of the communication network. And buffering the buffer area in correspondence with each sequence number, while monitoring the status of the system and / or communication path based on the reception status of the path through which each data of the same content passes. Data to be transmitted that has been transmitted in at least a duplex state by extracting each data buffered in the area in sequence number order Wherein the restoring processing.

  ADVANTAGE OF THE INVENTION According to this invention, the transmission system which increased the reliability of data transmission can be provided.

It is a lineblock diagram showing the transmission system concerning a 1st embodiment. It is a block diagram which shows the transmission system concerning 2nd Embodiment. It is a block diagram which shows the transmission system concerning an Example. It is explanatory drawing of the table information which showed the state and correspondence instruction | indication based on the confounding factor according to the reception condition used with the transmission system concerning an Example. It is explanatory drawing which showed the data relay operation | movement at the time of normal of the transmission system concerning an Example. It is explanatory drawing which showed the data relay operation | movement when a malfunction generate | occur | produces in the transmission area from a transmission circuit (0 system) to a receiving circuit (0 system) in the transmission system concerning an Example. It is explanatory drawing which showed the data relay operation | movement after a transmission device received reception monitoring information in the transmission system concerning an Example. It is explanatory drawing which showed the data relay operation | movement after coping with the failure of a receiving circuit (system 0) in the transmission system concerning an Example. It is explanatory drawing which showed the data relay operation | movement after coping with the failure of a transmission circuit (system 0) in the transmission system concerning an Example. It is explanatory drawing which showed the data relay operation | movement after addressing the failure of a transmission circuit (1 system) and a receiving circuit (0 system) in the transmission system concerning an Example. It is explanatory drawing which showed the processing concept of the transmission system using the duplexed transmission line which performs non-instantaneous switching from an active system at the time of a system failure. It is explanatory drawing which showed the transition at the time of 0 system failure with the transmission system shown in FIG. It is explanatory drawing which showed the transition at the time of both systems failing in the transmission system shown in FIG.

  An embodiment of the present invention will be described with reference to FIGS. It should be noted that description of a known configuration related to the transmission system is simplified or omitted.

  As an explanation of this transmission system, it will be explained by dividing it into a transmission side device and a reception side device. For the sake of explanation, data to be relayed is referred to as a frame.

[First Embodiment]
FIG. 1 is a configuration diagram illustrating a redundant transmission system according to the first embodiment.
The transmission side device 10 copies each frame in a duplex state, and also assigns each frame copied so that each frame is maintained in the duplex state on the communication network 30, and is responsible for different systems. It includes transmission circuits 12 and 13. Each frame is given a sequence number indicating the continuity of the frame before being duplicated. The same sequence number may be given after copying. In addition, information on the destination and the transmission source is given to each frame as necessary, and is sent to the communication network 30 via the transmission circuits 12 and 13.
As described above, in the transmission side device 10, for the received frame data sequence to be transmitted, a sequence number is assigned to each frame, and different communication paths are taken from different systems, and frames having the same contents are duplicated. It operates to send to the communication network 30. Further, as necessary, the transmission side device 10 operates to distribute the copied frames having the same contents so as to pass through different paths as much as possible and send them to the communication network 30.

  The receiving-side device 20 refers to a buffer memory 21 having an area corresponding to each sequence number, receiving circuits 22 and 23 that operate as respective systems for receiving frames via the communication network 30, and the sequence numbers of the respective frames. A data distribution unit 24 that distributes frames to a predetermined area of the corresponding buffer memory 21 and a data reading unit 25 that reads data from the buffer memory 21 based on an arbitrary rule are configured. The frame data recorded in each area of the buffer memory 21 may be buffered only by the first frame having the same contents. Further, it may be overwritten each time. Further, when the data inspection such as CRC is performed up to this point, it is desirable that the erroneous data is not buffered. Further, as the data inspection, the inspection may be performed at the time of writing different duplicated data that should have the same contents into the buffer memory 21.

The receiving side device 20 is provided with a transmission system monitoring unit 26 that monitors the condition of the communication path of each system and frame with reference to the reception state of the path through which each frame having the same content passes. .
Both frames having the same contents sent out in duplicate are received from the respective systems (reception circuits 22 and 23), distributed to each area of the buffer memory 21 by the data distribution unit 24, and the data reading unit 25. Is read as appropriate.

  It should be noted that both frames having the same contents transmitted in duplicate may be received from the same system (only one of the receiving circuits 22 and 23) depending on the distribution by the transmitting apparatus 10. Even in this case, the received both frames having the same contents are distributed to each area of the buffer memory 21 by the data distribution unit 24 and appropriately read by the data reading unit 25.

  As described above, the receiving-side apparatus 20 monitors the state of the system and / or the communication path while buffering each data received from any system via the communication network 30 in correspondence with each sequence number. To do. The receiving side device 20 takes out each data buffered in the buffer memory 21 according to a desired mode such as sequence number order, restores it to a frame data string, and transmits it to the next device.

  The communication network 30 has a configuration that can take a plurality of communication paths. It is desirable to support QoS management, tunneling, and flow control as necessary.

The transmission system monitoring unit 26 collects and monitors the reception status of the route through which each data having the same content passes through the conditions related to the communication of the transmission system. The analysis result may be notified to the machine or the administrator as accumulation, notification, alarm, or the like as necessary.
In the analysis process, the problem location is derived by comparing each received data with the data before and after the same system, the data passing through the same route in the communication network, or the data that overlaps part of the route. Just do it.

 In addition, a data delay amount and an error rate may be added to the analysis processing. For example, the manager may be informed if the frame including the predetermined path portion has not arrived / data has changed / a great delay has occurred. In addition, if there is a path portion that is more delayed than the statistical past delay amount, an alarm may be issued.

  Further, the reception side apparatus may be configured to automatically / semi-automatically switch the reception path based on the monitoring result of the state of the system and / or the communication path. For example, the receiving circuit 22 or 23 operating as each system is operated so as to acquire a frame received by the other, or one receiving circuit part alone can be arbitrarily connected to another receiving circuit via the communication network 30. A frame (one redundant frame) may be transferred.

  Moreover, you may comprise so that the transmission side apparatus 10 may be notified of path | route switching based on the monitoring result of the state of a system | strain and / or a communication path | route. By this notification, the transmission side apparatus 10 switches information specifying the route or system included in the destination information. For example, both systems may be notified to be sent to the same receiving device, or may be notified to change the frame passage route (transmitting device, VPN, specific flow, etc.). In addition, it is also possible to notify the parameter indicating the importance or priority to be given to an arbitrary frame (one redundant frame) that passes through a route with a large amount of non-delivery or delay, so that the parameter is changed to higher or higher. is there.

Further, table information for determining the problematic system and / or the location of the communication path may be provided. The transmission system monitoring unit 26 may perform measures such as automatically narrowing down a problem / requesting necessary information from an administrator or a peripheral device / automatically solving a problem while referring to the table.
For example, when frames that have not arrived are concentrated in one system, a notification that it is necessary to check the state of the receiving circuit of that system or a warning that a failure has occurred may be issued. Further, it may have an operation of acquiring desired information that contributes to problem solving from the devices constituting the communication network 30, and may proceed with measures such as problem narrowing and problem solving.

  Thus, according to the present transmission system, the reliability of the data transmission system can be further improved as compared with the existing system.

  For example, as described above, even if the receiving frame data cannot be received due to a failure in one of the duplexed receiving systems, the transfer normally sent from both transmitting systems Frame data is received by one receiving system that is operating normally, and duplexing of the transmission device and the transfer route can be maintained as much as possible. As a result, more redundancy can be ensured.

  Further, it is possible to maintain the duplication of the transfer data as much as possible, and the receiving side has a mechanism for receiving two duplication of transfer data constantly.

  Further, even if transfer data is lost intermittently on the transmission route, it is possible to realize the transmission system to receive correct data as long as both of the duplicated transfer data are not lost simultaneously.

[Second Embodiment]
Next, a second embodiment will be described. This system also has transmission system monitoring means on the transmission side. Moreover, each transmission system monitoring means cooperates. Note that description of parts similar to those of the first embodiment is simplified or omitted.

FIG. 2 is a configuration diagram illustrating a redundant transmission system 2 according to the second embodiment.
The transmission side device 10 is provided with a data replication unit 11 and transmission circuits 12 and 13, as well as a transmission system monitoring unit 14 that monitors the condition of each system and frame communication path.
In the transmission side device 10, with respect to the received frame data sequence to be transmitted, a sequence number is assigned to each frame and a frame having the same content is sent to the communication network 30 in a double state while being transmitted to the communication network 30. Operates to monitor problem areas in the transmission system in cooperation.

The transmission system monitoring unit 14 may analyze a condition related to communication of the transmission system by using a reception state of a route through which each data having the same content passes. The analysis result may be notified to the machine or the administrator as accumulation, notification, alarm, or the like as necessary.
The information used for this analysis processing may be used by receiving notification of the analysis result (problem location, problem system, failure prediction, etc.) itself from the transmission system monitoring unit 26 of the receiving-side device 20, or each of the same contents. Each reception status (reception status information) of a route through which data passes may be accepted and used as reception monitoring information. Further, a part or all of the reception monitoring information may be acquired from the transmission system monitoring unit 26 together with the analysis result.
In the analysis processing using the reception monitoring information, individual data received by the receiving-side device 20, data before and after the same system, data passing through the same route in the communication network, and data overlapping a part of the route Thus, the problem part may be derived similarly to the transmission system monitoring unit 26.

Even when the analysis result is received from the transmission system monitoring unit 26, the transmission system monitoring unit 14 may perform re-verification processing by adding information held by the own device. For example, when one of the delay amounts of a certain frame is notified as a problem, it is possible to perform processing for comparison with its own transmission history. Depending on the cause of the problem, there may occur a case in which one of the same frames is transmitted to the communication network 30 with a delay compared to the other at the time of transmission from the transmission side device 10. In such a case, the problem can be solved by re-verification processing. You can also check whether the problem pointed out has been recovered.
Further, the transmission side apparatus 10 may automatically / semi-automatically switch the data transmission path based on the monitoring result of the state of the system and / or the communication path.

  Moreover, you may comprise so that route switching based on the monitoring result of the state of a system | strain and / or a communication route may be negotiated between the receiving side apparatuses 20. FIG. This negotiation makes it easy to switch the receiving circuit used by the receiving side apparatus 20 as the same system and to measure the timing.

  Similarly to the transmission system monitoring unit 26, table information for determining the problematic system and / or the location of the communication path may be provided.

  Note that the transmission system monitoring unit 14 and the transmission system monitoring unit 26 may perform monitoring and response by sequentially exchanging various types of information as necessary, and may appropriately identify and notify problems.

  As described above, the transmission side device 10 monitors the state of the system and / or the communication path by using the reception status of each data received by the reception side device 20 via the communication network 30. Moreover, what is necessary is just to perform alerting | reporting, a warning, a transmission circuit change, and the change of provision information as needed.

As described in the first embodiment, the reception-side device 20 includes the buffer memory 21, the reception circuits 22, 23, the data distribution unit 24, the data reading unit 25, and the transmission system monitoring unit 26.
The receiving-side apparatus 20 monitors the status of the system and / or communication path while buffering each data received from any system via the communication network 30 in association with each sequence number. The receiving side device 20 takes out each data buffered in the buffer memory 21 according to a desired mode such as sequence number order, restores it to a frame data string, and transmits it to the next device.

  The transmission system monitoring unit 26 may perform the processing operation described in the first embodiment and monitor the conditions related to the communication of the transmission system. Moreover, what is necessary is just to exchange the monitoring result and various information required for monitoring with the transmission system monitoring part 14 voluntarily / in response to a request. Further, it may be configured to accept and reply to a request regarding collection of various types of information used for verification processing and identification of a problem location from the transmission system monitoring unit 14.

  As described above, the transmission system monitoring unit 14 of the transmission side apparatus 10 and the transmission system monitoring unit 26 of the reception side apparatus 20 confirm the normality of the communication path in an arbitrary section within the communication network, either alone or in cooperation. It may be operated as follows. For example, for an arbitrary section with a large delay amount, if the priority is adjusted, it can be accepted as a frame transmission path, and whether or not the non-transmission section is still unchecked, the frame passage path and additional information are verified. You can confirm by changing. Examples of the grant information operated on the transmission side apparatus 10 include QoS-related information, information indicating the tunneling state of the communication path, and setting information regarding flow control. By adjusting these parameters, it is searched whether or not the problem in the communication path has converged. As described above, confounding factors may be assumed to solve the problem in addition to avoiding the problem part.

  Thus, according to the present transmission system, the reliability of the data transmission system can be further improved as compared with the existing system.

  For example, as described above, even if the transmission / reception system cannot be received due to a failure of one of the transmission / reception systems among the duplexed transmission / reception systems, the other operating normally Transmit as much as possible from the transmission system to the reception system of both systems, or transmit the transfer frame data normally transmitted from both transmission systems to one of the reception systems that are operating normally. Duplication of part or all of the transmission device, reception device, and transfer route can be maintained. As a result, more redundancy can be ensured. As a result, even if a failure (disconnection location) occurs in both of the two systems, such as a double failure in the existing system, it is possible to maintain a high possibility of securing a conduction route.

Next, examples will be described.
FIG. 3 is a block diagram showing a transmission system according to an embodiment of the present invention. FIG. 4 is an explanatory diagram visualizing table information used in the transmission system monitoring unit of the embodiment.

  In the present embodiment, each data transmitted from the partner apparatus through different communication paths of the communication network is monitored by collecting a flag group that can identify the route. In this monitoring, the status of the system and / or communication path is monitored based on the status of identification information (flag group corresponding to the sequence number) and the delay amount of each frame.

In the configuration of the embodiment shown in FIG. 3, the sequence number assigned to the frame data A uses a circulation number from 0 to 7, counts up from 0 to 7 one by one, returns to 0 after 7 and counts again. Shall be up.
In the transmission apparatus 100, the sequence number insertion unit 110 sequentially and sequentially incorporates the sequence numbers from “0” to “7” into the frame data A to be transmitted. In addition, the storage area of the buffer memory of the receiving apparatus 200 has a configuration in which storage areas for sequence numbers 0 to 7 are prepared.

The frame data A in which the sequence number is incorporated is copied into two by the frame data duplicating unit 120 and is sent to the frame data B ₀ directed to each transmission circuit 131 (0 system side) and to the transmission circuit 132 (1 system side). It becomes the frame data B ₁ that goes.

In the frame data B ₀ and the frame data B ₁ , the destination information and the source information are incorporated by the destination information adding units 141 and 142.
This destination information is given by the destination control unit 150 so as to ensure a double state in correspondence with the sequence number. Also, the destination control unit 150 receives the notification from the destination monitoring unit 160 and changes the algorithm to which the destination is assigned.

The destination monitoring unit 160 cooperates with the transmission system monitoring unit of the receiving device 200 to monitor the state of the system and the communication path, and switches the destination of the frame so as to switch the frame passage path so as to avoid the problem location based on the monitoring result. The control unit 150 is notified.
Destination information and the like given to frame data having the same contents are individually managed for each frame so as to ensure more double state classifications corresponding to sequence numbers. Further, management is performed so as to designate or change a physical / logical route within the communication network 300 for each frame data as necessary.
As a method of changing the destination, any method may be used as long as the frame data having the same contents can be duplicated and transmitted to the partner apparatus as desired from the transmission apparatus 100.

For example, the destination control unit 150 refers to the sequence number incorporated in each data frame B ₀ and B ₁ to be transmitted so that the transmission route of the frame data to be transmitted is not fixed, and operates according to an arbitrary rule. It is sufficient to switch the passage route or the like. In this rule, for example, the destination information is dynamically switched according to the odd / even sequence numbers. Further, the switching may be performed dynamically so as to be different depending on the value of the sequence number.
In addition, when receiving the reception monitoring information from the reception status monitoring control unit 272 that is a part of the transmission system monitoring unit of the receiving device 200 when determining the destination, the information is referred to and reception abnormality occurs. The destination information is changed in units of each frame data in order to identify the fact that this is done from the flag group and to secure more duplication. The table in FIG. 4 is a list that summarizes the estimated states according to the confounding factors that can be identified from the flag group and the processing that is performed automatically / semi-automatically. Information corresponding to the contents of this table and the corresponding policy are appropriately provided in the form of table information or an algorithm in the program by the transmitting apparatus 100 and the receiving apparatus 200 to cope with problem avoidance and solution.

The transmission circuit 131 (0 system side) and the transmission circuit 132 (1 system side) send frame data B ₀ and frame data B ₁ to the communication network 300 in association with dynamically changing paths.

  In the communication network 300, each node in the communication network relays the frame as appropriate according to the destination information and transmits the frame to the destination.

In the receiving apparatus 200, a receiving circuit 211 (0 system side) and a receiving circuit 212 (1 system side) are connected to the communication network 300, and each receiving circuit receives each frame in which destination information addressed to itself is incorporated. To do.
At this time, the receiving circuit 211 (system 0 side) and the receiving circuit 212 (system 1 side) remove the destination information and the source information attached to the frame on the transmission side, respectively, and also receive the destination information and the source of the received data frame. The data is handed over to the write controllers 221 and 222 so as to be associated with the frame data so that it can be discriminated as information.
The frame data C ₀ and C ₁ received by the receiving circuit 211 (0 system side) and the receiving circuit 212 (1 system side) were confirmed as necessary for any abnormality such as a bit error. Later, the sequence number extraction units 231 and 232 respectively extract sequence numbers incorporated on the transmission side. The extracted sequence numbers are delivered to the write control units 221 and 222, respectively.
Note that the frame data may be discarded when an abnormality such as a bit error is detected in the received frame data, and a retransmission request may be automatically made when an abnormality is detected in both systems. .

The frame data distribution units 241 and 242 distribute the frame data C ₀ and C ₁ to each storage area of the buffer memory 250 corresponding to the sequence number. This distribution is controlled by the write control units 221 and 222 based on the sequence number.

The write control units 221 and 222 sequentially store the frame data C ₀ and C ₁ in the storage areas prepared in the buffer memory 250 corresponding to the sequence numbers incorporated in the frame data. The data distribution units 241 and 242 are controlled.
Further, based on the destination information and the transmission source information passed from the receiving circuit 211 (0 system side) and the receiving circuit 212 (1 system side), the frame data C ₀ and C ₁ are written to the buffer memory 250 and monitored. Each corresponding flag bit of the use flag 260 is ignited to make it possible to identify which route (device, flow, virtual route, etc.) the stored frame data has passed. In this example, “4” is used for the number of bits of the monitoring flag 260 so as to cover the combinations of the transmission circuit and the reception circuit. Furthermore, by increasing the number of flags, it becomes possible to classify more detailed faults and the like.

  The buffer memory 250 has a buffer area for the set sequence number, and is associated with a monitoring flag 260 that can identify which route the frame data has passed for each area of each section. .

In the buffer memory 250, the frame data is stored in an area corresponding to the sequence number assigned to the frame data to be buffered from the frame data sorting units 241 and 242.
The monitoring flag 260 of this embodiment is composed of 4 bits from “F0” to “F3”.
The flag bit “F0” indicates that frame data has been received from the transmission circuit 131 (0 system side) via the reception circuit 211 (0 system side).
The flag bit “F1” indicates that frame data has been received from the transmission circuit 132 (1 system side) via the reception circuit 211 (0 system side).
The flag bit “F2” indicates that frame data has been received from the transmission circuit 132 (1 system side) via the reception circuit 212 (1 system side).
The flag bit “F3” indicates that frame data has been received from the transmission circuit 131 (0 system side) via the reception circuit 212 (1 system side).

  The data reception monitoring unit 271 reads the ignition state of each flag bit, that is, the arrival status of each frame data via various conduction routes, and passes the contents to the reception status monitoring control unit 272 and the reading control unit 280.

  The read control unit 280 controls the frame data reading unit 290 to read the frame data from the buffer memory 250 in the order of the sequence number based on the frame data arrival status from the data reception monitoring unit 271.

  The frame data reading unit 290 reads frame data in the designated storage area under the control of the reading control unit 280. As the frame data is read, the contents of the corresponding flag bit are also deleted.

  The reception status monitoring control unit 272 acquires from the data reception monitoring unit 271 the frame reception status information (reception presence / absence, delay amount, etc.) acquired from the reception circuit 211 (0 system side) and the reception circuit 212 (1 system side). The reception status information (flag group ignition status) indicating the arrival status of the frame data is transferred to the destination monitoring unit 160 of the transmission device 100 as reception monitoring information.

Next, processing operation examples of the transmission system according to the embodiment will be described with reference to FIGS.
In the following description, a configuration in which sequence numbers 0 to 5 are used cyclically will be described. For this reason, an equal number of buffer areas and flag areas are also secured in the receiving apparatus 200. Further, illustration of a part of the configuration is omitted to simplify the description.

  FIG. 5 shows the data relay operation at the normal time.

The transmission apparatus 100 assigns a sequence number (see SN.1 of frame A in the figure) to the frame data to be transmitted, and after copying to two, assigns the transmission system as appropriate (SN. In the figure). 0 frame B ₀ , B ₁ ), the transmission circuit (0 system) 131 and the transmission circuit (1 system) 132.
At this time, during normal operation, the route is dynamically switched according to whether the sequence number given to the frame data B to be transmitted is an even number or an odd number.

  In one specific example, when the sequence number assigned to the frame data to be transmitted is an odd number, the destination information is assigned and transmitted so as to be received by a different system. When the sequence number is an even number, the destination information is given and transmitted so as to be received by the same system.

As a result, both odd-numbered frame data are transmitted from the transmission circuit (0 system) 131 to the reception circuit (1 system) 212 and from the transmission circuit (1 system) 132 to the reception circuit (0 system) 211, respectively.
Similarly, both even-numbered frame data are transmitted from the transmission circuit (system 0) 131 to the reception circuit (system 0) 211 and from the transmission circuit (system 1) 132 to the reception circuit (system 1) 212, respectively.

In the figure, frames C ₀ and C ₁ with a sequence number “4” and frames D ₀ and D ₁ with a sequence number “5” are being transferred through the communication network 300. Both the frame data are sent from the transmission device 100 so as to pass through different paths. As a technique for this, the destination control unit 150 manages the source information and the destination information so as to alternate.

  Both receiving circuits of the receiving apparatus 200 refer to the destination information incorporated in the identified frame and appropriately receive the frame data.

Each received frame data is sequentially stored in the corresponding storage area of the buffer memory 250 that matches the incorporated sequence number. Along with this buffering, a flag matching the set of source information and destination information identified at the time of reception is lit.
Specifically, when it is transmitted from the transmission circuit (system 0) 131 and received by the reception circuit (system 0) 211, the flag bit "F0" is ignited.

Similarly, the “F1”, “F2”, and “F3” flag bits are appropriately ignited for each route.
When the received frame data is written to the storage area of the corresponding sequence number, if any of the flags “F0” to “F3” has already ignited, the storage area already has frame data from another route. Is stored. In other words, by sequentially igniting the corresponding flag bit, it is possible to extract information indicating that the signal can be received from the corresponding route.

  Referring to each flag row in the figure, “F0” and “F2” are ignited for the frame data whose sequence number is “0”. This indicates that both the route from the transmission circuit (system 0) 131 to the reception circuit (system 0) 211 and the route from the transmission circuit (system 1) 132 to the reception circuit (system 1) 212 can be received. Yes.

  Similarly, “F1” and “F3” are ignited for the frame data whose sequence number is “1”. This indicates that both the route from the transmission circuit (system 1) 132 to the reception circuit (system 0) 211 and the route from the transmission circuit (system 0) 131 to the reception circuit (system 1) 212 can be received. Yes.

On the other hand, only “F2” is ignited for the frame data whose sequence number is “2”. This indicates only that frame data (F ₁ not shown) can be received from the transmission circuit (system 1) 132 via the route of the reception circuit (system 1) 212. The frame data having the same data content (F _{0 in the} figure) indicates that the buffer memory has not been reached. When the frame data F ₀ in this state reaches the area of the sequence number "2" of the buffer memory, the flag bit "F0" ignites. At this time, since the frame data F is written in the corresponding area of the buffer memory, the frame data F may not be written or may be written.

On the other hand, no flag is lit for the frame data with the sequence number “3”. When the frame data E ₀ and E ₁ reach the buffer memory, buffering and ignition of the corresponding flag are performed.

  For the frame data with the sequence number “4”, no flag is lit. This is because buffer data (G in the figure) is read by the read control unit 280, the flag information is cleared, and frame data whose next sequence number is “4” is not buffered.

Next, the data reception monitoring unit 271 estimates the ignition status of each flag of the monitoring flag 260 and the transmission timing of other frame data, and notifies the read target and timing of each buffered frame data.
At this time, if both of the flag bits “F0” and “F2” indicating the path through which the frame data with an even sequence number has passed are already lit, the frame data is set at a predetermined interval from the previous frame data. Is sent to the next device.
Similarly, if both of the flag bits “F1” and “F3” indicating the path through which the frame data with an odd sequence number has passed have already been ignited, the frame data is set at a predetermined interval from the previous frame data. Is sent to the next device.

According to the system configuration, transmission may be performed in order of sequence numbers, transmission may be performed in the order in which both multiplexed frames have arrived, or read control may be executed as appropriate.
For example, if it is set to read the storage area of the sequence number that is -3 with respect to the sequence number in which both the flags “F0” and “F2” or both the flags “F1” and “F3” are ignited, Therefore, frame relay can be realized at moderate intervals.
In the example of FIG. 5, the data reception monitoring unit 271 identifies that the storage of the frame data having the sequence number “1” is completed, and reads the data from the area of the sequence number “4” that is −3 from the sequence number. It is shown that the data is output as frame data D.
This mechanism makes it possible to keep the read-side cycle constant even if the arrival cycle of the frame data varies.

On the other hand, even if both flags are not aligned within a predetermined time, the frame data is sent to the next apparatus with a predetermined interval from the previous frame data.
At this time, the data reception monitoring unit 271 notifies that both flags are not aligned. The data reception monitoring unit 271 also notifies when any flag is not lit. That is, it notifies that a problem has occurred in the communication path or the like.

  As a result, even when the signal delay amount is different for each transmission section route, reading is performed after receiving the frame data of the two paths, and duplexing of the frame data can be realized.

  Note that erasure of the flag may be appropriately performed together with erasure of the memory area at a predetermined interval or when data reading is completed.

  FIG. 6 shows the data relay operation when a problem occurs in the transmission section from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211.

When an abnormality occurs in this section, the frame passing from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211 is delayed or undelivered. That is, one of the frames with an even sequence number is not processed normally.
For this reason, frame data from the transmission circuit (system 1) 132 via the reception circuit (system 1) 212 route is written in the corresponding buffer memory area having an even sequence number.

  At this time, a flag group attached to the corresponding buffer memory area of the monitoring flag 260 is a flag indicating that frame data from the transmission circuit (1 system) 132 via the reception circuit (1 system) 212 route can be received ( Only F2) ignites.

  Note that an odd-numbered frame does not pass through the transmission route from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211. Therefore, the normal flags (“F1” and “F3”) are ignited in the flag group of the buffer memory area.

Even in the above state, the receiving apparatus 200 ensures the normality of the frame relay by using one of the even-numbered frames that have reached the normal path. More specifically, the data reception monitoring unit 271 and the read control unit 280 identify the ignition status of the other flag (F2) of the corresponding sequence number at the time when the read timing comes, and the frame data of the corresponding memory area is obtained. Forward.
In this state, due to a failure in the transmission section from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211, duplication is not ensured for the frame data whose sequence number is even.

  The data reception monitoring unit 271 transmits to the reception status monitoring control unit 272 the status of the system and / or communication path and the status of the flag group through which the frame data has passed as reception status information. In this transmission, all the monitoring flags may be transmitted, or only a portion having a problem may be transmitted. When only the problematic part is transmitted, it is only necessary to transmit that “F0” is not ignited and only “F2” is ignited for the frame data having an even sequence number.

  Using this information, there is some abnormality on the transmission path from the transmission circuit (system 0) 131 to the reception circuit (system 0) 211, and in the route between the transmission circuit (system 0) 131 and the reception circuit (system 0) 211, Notify the partner device that the frame data could not arrive correctly.

The reception status monitoring control unit 272 generates reception monitoring information by using the reception status information (ignition status information of the flag group) from the data reception monitoring unit 271.
For example, if the communication is interrupted for a predetermined period of time or less, it is ignored as a temporary failure. However, when the predetermined period is exceeded, the transmission circuit (0 system) 131 to the reception circuit (0 system) 211 are ignored. What is necessary is just to judge to the transmission path failure of a area, and to notify the transmission apparatus 100 side and a maintenance person.
Similarly, if the frame itself has arrived but the data has been corrupted (garbled), a warning will be sent for the first time, and if it occurs continuously / intermittently, a transmission line abnormality will be reported. Good.
Similarly, if the amount of delay is larger than that of other routes, it is only necessary to notify that the transmission path is to be changed.

  FIG. 7 illustrates a data relay operation when the transmission apparatus 100 receives reception monitoring information indicating that a transmission path abnormality has been notified. The abnormality in this example is a section from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211.

  When the destination control unit 160 receives the reception monitoring information, the transmission device 100 tries to cope with a change in the transmission path so as to solve the problem.

  In this example, as an operation to ensure duplication of frame data, the destination monitoring unit 160 and the destination control unit 150 cooperate with each other to specify even-numbered frame destinations for the frames output from the transmission circuit (system 0) 131. The reception circuit (1 system) 212 is changed, and the frame destination having an odd sequence number is set in the reception circuit (1 system) 212. As a result, the frame output from the transmission circuit (system 0) 131 can be transmitted from the transmission circuit (system 0) 131 to the counterpart device through a path that does not pass through the reception circuit (system 0) 211 section.

  In addition, a mechanism for adjusting the traffic amount is operated so as not to apply an excessive load on the network and the counterpart device in accordance with the above processing operation and to flatten the risk at the time of failure.

When only the processing for avoiding the above part of the paths is performed on the transmission side, frames are concentrated on the reception circuit (system 1) 212. If the receiving circuit (system 1) 212 fails in such a state, the influence for a while is great.
Therefore, the destination monitoring unit 160 cooperates with the destination control unit 150 to adjust the path of even-numbered frame data transmitted from the transmission circuit (1 system) 132 to the reception circuit (0 system) 211. Operate to output. As an adjustment, transmission of an arbitrary route is stopped.
As a result, the routes for the frames with even sequence numbers are the routes from the transmission circuit (0 system) 131 to the reception circuit (1 system) 212 and from the transmission circuit (1 system) 132 to the reception circuit (0 system) 211. There are a total of three places, the route and the route from the transmission circuit (system 1) 132 to the reception circuit (system 1) 212 that are transmitting and receiving from normal time. Therefore, in this case, by temporarily stopping transmission using the route from the transmission circuit (system 1) 132 to the reception circuit (system 1) 212, it is possible to reduce the burden on the nearby network.

  When both transmission path change processes are performed, there are two routes: a route from the transmission circuit (system 0) 131 to the reception circuit (system 1) 212 and a route from the transmission circuit (system 1) 132 to the reception circuit (system 0) 211. It becomes possible to maintain the duplication of the frame using.

  While the changed route is used and the frame data is duplicated, the transmission route from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211 and the transmission circuit (1 system) Frame transmission on the transmission route of the receiving circuit (system 1) 212 from 132 is stopped.

  On the other hand, even in such a state, the frame is transmitted to the transmission route that is stopped in an arbitrary period. With this frame relay operation, the recovery status and normality of these transmission routes can be confirmed. As a frame to be transmitted to the abnormal path, a frame different from the duplicated frame is prepared. In addition, as a frame to be transmitted to the path for confirming normality, a frame different from the duplicated frame may be prepared, or one of them may be transmitted to the path only at the timing.

  For example, when the sequence number is an arbitrary number (for example, number 0) with a fixed period, the frame data is copied into four, the transmission route from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211, and the transmission circuit Also output from the (system 1) 132 to the transmission route of the receiving circuit (system 1) 212.

After this transmission, by confirming the reception status (flag group of the corresponding sequence number, etc.) fed back, it is possible to resolve abnormalities and problems and identify the normality of the path.
If the problem has been solved, it can be confirmed that the state is “normal for all communication routes” (see item number 15 shown in FIG. 4).

  If it is considered that the problem of the abnormal part has been solved based on the time passage and the confirmation result of several degrees as necessary, the operation may be returned as in the normal state shown in FIG.

  As described above, the network load is increased by increasing the number of specific frames. However, the recovery status of the transmission route can be confirmed without overloading the network by checking only the frames with a specific sequence number with a certain period. It is possible to check the status. In addition, the function of confirming the situation with a simple load may be provided for the non-path portion without using the frame data to be transmitted.

Next, another processing example will be described.
FIG. 8 shows a data relay operation when the receiving circuit (system 0) 211 fails.
When the reception circuit (system 0) 211 fails, the transmission circuit (system 0) 131 receives from the transmission circuit (system 1) 132 frame data with an even sequence number passing through the route of the reception circuit (system 0) 211. Frame data with an odd sequence number passing through the route of the circuit (system 0) 211 does not reach the buffer memory 250.
Therefore, “F0” and “F1” of the monitoring flag 260 are not ignited.

  When this information is notified to the transmission apparatus 100 side, the transmission apparatus 100 changes the transmission route using the reception circuit (system 0) 211 to another route.

In this example, a frame with an even sequence number is output from the transmission circuit (system 0) 131 to the route of the reception circuit (system 1) 212, and the transmission circuit (system 1) 132 outputs the frame of the reception circuit (system 1) 212. Output odd numbered frames to the root.
Thereby, duplex transfer of frame data using the route from the transmission circuit (0 system) 131 to the reception circuit (1 system) 212 and the route from the transmission circuit (1 system) 132 to the reception circuit (1 system) 212 is realized. .

  In order to confirm the recovery status of the receiving circuit (system 0) 211, the arrival status may be monitored by temporarily outputting frame data with a certain period even for the temporarily stopped route. If it can be confirmed that the frame is stably received for a certain period, the transmitting apparatus 100 assumes that the failure has been resolved and returns to the normal state. According to this method, recovery from a failure can be confirmed without using another signaling method.

Next, a similar processing example will be described.
FIG. 9 shows a data relay operation when the transmission circuit (system 0) 131 fails.
When the transmission circuit (0 system) 131 breaks down, it receives the frame data of the even number sequence number passing through the route from the transmission circuit (0 system) 131 to the reception circuit (0 system) 211 and the transmission circuit (0 system) 131. Frame data with an odd sequence number passing through the route of the circuit (system 1) 212 does not reach the buffer memory 250.
Therefore, “F0” and “F3” of the monitoring flag 260 are not ignited.

  When this information is notified to the transmission apparatus 100 side, the transmission apparatus 100 changes the transmission route using the transmission circuit (system 0) 131 to another route.

In this example, a frame with an even sequence number is output from the transmission circuit (system 1) 132 to the route of the reception circuit (system 0) 211, and the transmission circuit (system 1) 132 outputs the frame of the reception circuit (system 1) 212. Output odd numbered frames to the root.
This realizes duplex transfer of frame data using the route from the transmission circuit (system 1) 132 to the reception circuit (system 0) 211 and the route from the transmission circuit (system 1) 132 to the reception circuit (system 1) 212. .

  In order to check the recovery status of the transmission circuit (system 0) 131, the arrival status may be monitored by temporarily outputting frame data with a certain period even for the temporarily stopped route. If it can be confirmed that the frame is stably received for a certain period, the transmitting apparatus 100 assumes that the failure has been resolved and returns to the normal state. According to this method, recovery from a failure can be confirmed in a self-perceptive manner.

Next, an example of processing in which each transmission / reception has a failure location will be described.
FIG. 10 shows a case where the receiving circuit (system 0) 211 shown in FIG. 8 is out of order and the transmitting circuit (system 1) 132 is further out of order. Conversely, the case where the reception circuit (system 0) 211 fails in the situation where the transmission circuit (system 1) 132 is out of order is the same as that shown in FIG.
In this state, a failure has occurred at the same location as the double failure shown in FIG.

First, as in FIG. 8, while the reception circuit (system 0) 211 is out of order, the transmission circuit (system 0) 131 sends the transmission circuit to the reception circuit (system 1) 212 and the transmission circuit (system 1) 132. Frame data is transmitted and received through a route sent to the receiving circuit (system 1) 212.
If the transmission circuit (system 1) 132 fails in this state, the only transmission route that can be used is the route from the transmission circuit (system 0) 131 to the reception circuit (system 1) 212.

  When the reception circuit (system 0) 211 fails, the transmission circuit (system 0) 131 sends the transmission circuit to the reception circuit (system 1) 212, and the transmission circuit (system 1) 132 transmits to the reception circuit (system 1) 212. Both the even and odd frames with sequence numbers are transmitted in the route to be transmitted. For this reason, since the duplex state is maintained, even if the transmission circuit (system 1) 132 suddenly fails while the reception circuit (system 0) 211 is out of order, the frame relay is performed without loss of frame data. Can continue.

Similarly, in the situation where the transmission circuit (system 1) 132 has failed previously, the route from the transmission circuit (system 0) 131 to the reception circuit (system 0) 211 and the transmission circuit (system 0) 131 Frame data is transmitted and received through a route sent to the receiving circuit (system 1) 212.
If the receiving circuit (system 0) 211 fails in this state, the only available transmission route is the route between the transmission circuit (system 0) 131 and the reception circuit (system 1) 212.

  When the transmission circuit (system 1) 132 breaks down, a transmission route from the transmission circuit (system 0) 131 to the reception circuit (system 0) 211, and transmission from the transmission circuit (system 0) 131 to the reception circuit (system 1) 212 For this reason, since the duplex state is maintained in the route to be transmitted, even if the receiving circuit (system 0) 211 suddenly fails while the transmission circuit (system 1) 132 is out of order, the frame data is lost. Frame relay can be continued without doing.

  In this way, in a device that transmits and receives frame data between two devices using a transmission system of the active system and the standby system, when the transmission side or the reception side or one system in the transmission section fails, autonomously Provide a mechanism for constantly ensuring duplication of frame data while appropriately changing the transmission destination so as to avoid the cause.

With this mechanism, it is possible to maintain redundancy as a transmission system and improve the reliability of data communication.

  Also, when transferring redundant frames, the prepared transmission routes are not used separately for the active and standby systems, but all transmission routes are used after using transmission routes that cross between systems. In this way, data transmission is performed to distribute the transfer data. Thus, the normality of the transmission route can be confirmed without using a frame or packet only for normality confirmation.

  Each part of the transmission system may be realized using a combination of hardware and software. In a form in which hardware and software are combined, a transmission device program or a reception device program is developed in the RAM, and hardware such as a control unit (CPU) may be operated based on the program. Further, the program for the transmission device and the program for the reception device may be programmed so as to be commonly used on the transmission side and the reception side.

  The program may be recorded in a fixed manner on a storage medium and distributed. The program recorded on the recording medium is read into a memory via a wired, wireless, or recording medium itself, and operates a control unit or the like. Examples of the recording medium include an optical disk, a magnetic disk, a semiconductor memory device, and a hard disk.

  To describe the above embodiment in another expression, an information processing apparatus that operates as a transmission-side apparatus or a reception-side apparatus is based on the above-described program expanded in the RAM, sequence number insertion means, data duplication means, It can be realized by operating as part or all of the second transmitting means, the first and second receiving means, the data allocating means, the buffer memory managing means, the data reading means, and the transmission system monitoring means. .

  Although the embodiments and examples have been illustrated and described, the block configuration can be separated and merged, the procedure can be changed, and the combination can be freely changed as long as the gist of the present invention and the functions described are satisfied. It is not intended to limit the invention.

  For example, although duplex transmission has been described in the above description, multiple transfers such as triple transfer, quadruple transfer, and the like may be performed when further reliability is desired.

  As explained above, by appropriately performing transmission using not only transmission routes of the same system but also transmission routes with other systems, there are more choices of transmission paths, and when a failure occurs in the transmission section Even easier to secure the conduction path.

  Also, the frame data to be transferred is duplicated and transferred on the network, and can be received while being selected in units of frame data on the receiving side. For this reason, even if the frame data is damaged or the frame data is discarded due to the damage in the transmission section, data loss can be prevented unless two of the frame data are simultaneously damaged or discarded.

  For this reason, it is possible to easily maintain continuity by preventing loss of frame data. As a result, high reliability can be ensured even in data communication that requires continuity.

  In addition, since retransmission processing of frame data becomes unnecessary, it is possible to eliminate transmission delays associated with retransmission processing.

  In addition, in duplex packet transfer, instead of using the prepared transfer route separately for the active system and the standby system, if transfer data is distributed and transferred so that all routes are used, There is no need to use a data packet for checking the normality of the conduction route.

  In other words, according to the present invention, it is possible to provide a transmission system in which the reliability of data transmission is further increased.

DESCRIPTION OF SYMBOLS 1 Redundant transmission system 2 Redundant transmission system 10 Transmission side apparatus 11 Data duplication part 12, 13 Transmission circuit 14 Transmission system monitoring part 20 Reception side apparatus 21 Buffer memory 22, 23 Reception circuit 24 Data distribution part 25 Data reading part 26 Transmission system monitoring unit 30 communication network

The redundant transmission system according to the present invention takes a different communication path from a different system to a communication network that can take a plurality of communication paths while giving a sequence number to each data sequence having a time series to be transmitted. Transmitting from the partner device through a different communication path of the communication network, having a buffer device corresponding to each sequence number, and a transmission side device capable of transmitting while changing the communication route in at least a duplex state to the partner device The normality of each data that has been determined is determined, and each normal data is buffered in the arrival order corresponding to each sequence number in the buffer area, while the system and / or communication path status is the same sequence while monitoring on the basis of the reception state of a path, each of the identical data has been through with numbers, it is buffered in the buffer area By retrieving the data in the sequence number order, and having a receiving device for restoring processed data sequence is a transmission target that is transmitted from the transmitting device.

In the redundant transmission method according to the present invention, the transmission side device assigns a sequence number to each data sequence having a time series to be transmitted, and assigns different communication paths to a communication network that can take a plurality of communication paths. And sending to the partner device while changing the communication path in at least a duplex state , and the receiving side device has a buffer area corresponding to each sequence number, and from the partner device through a different communication path of the communication network. The normality of each transmitted data is determined, and each normal data is buffered in the arrival order corresponding to each sequence number in the buffer area, and the state of the system and / or communication path is the same. while monitoring on the basis of the reception state of a path, each of the identical data has been through with a sequence number, each data buffered in the buffer area By retrieving the sequence number order, characterized by restoration process a data string is transmitted to the transmission target from the transmission side apparatus.

Claims (30)

For the data string to be transmitted, a transmission side that can assign a sequence number to each other, take different communication paths from different systems, and send them to a communication network that can take a plurality of communication paths in at least a duplex state to the partner device Equipment,
A buffer area corresponding to each sequence number is provided, and each data transmitted from a partner device through a different communication path of the communication network is buffered in correspondence with the respective sequence number in the buffer area. While monitoring the status of the system and / or communication path based on the reception status of the path through which each data of the same content, and at least by extracting each data buffered in the buffer area in sequence number order, A redundant transmission system comprising: a receiving side device capable of restoring a data string to be transmitted that has been transmitted in a duplex state.   The redundant transmission system according to claim 1, wherein the reception side device switches the reception path based on a monitoring result of a system and / or a communication path state.   3. The redundant transmission system according to claim 2, wherein the receiving side device switches a receiving circuit so as to avoid a problem location based on a monitoring result of a state of a system and / or a communication path.   The redundant transmission system according to any one of claims 1 to 3, wherein the reception side device notifies the transmission side of a monitoring result.   The redundant transmission system according to claim 4, wherein the reception side device notifies the transmission side device of path switching.   The receiving-side apparatus has a table for determining a problematic system and / or a location of a communication path corresponding to a reception state of a path through which each data of the same content passes, 6. The redundant transmission system according to claim 1, wherein the communication path is derived based on the table.   The redundant transmission system according to any one of claims 1 to 6, wherein the transmission side device monitors a state of a system and / or a communication path in cooperation with the reception side device.   The redundant transmission system according to any one of claims 1 to 7, wherein the transmission side device switches a transmission path based on a monitoring result of a state of a system and / or a communication path.   9. The transmission side device according to claim 1, wherein the transmission side device switches a transmission path of transmission data so as to avoid a problem portion based on a monitoring result of a state of a system and / or a communication path. The described redundant transmission system.   10. The transmission side device according to claim 1, wherein the transmission side device switches a transmission circuit and a transmission path of transmission data so as to avoid a problem location based on a monitoring result of a state of a system and / or a communication path. The redundant transmission system according to one item.   The redundant transmission system according to claim 1, wherein the transmission side device negotiates a processing operation based on a monitoring result with the reception side device.   The transmission side apparatus dynamically changes a path for sending each piece of data having the same content to the reception side apparatus in correspondence with a sequence number, and sets a data string to be transmitted in at least a duplex state in a communication network The redundant transmission system according to any one of claims 1 to 11, wherein the redundant transmission system is transmitted to the network.   The transmission side device has a table for determining a problem system and / or a communication path location corresponding to a reception state of a path through which each data of the same content passes, and has a problem system The redundant transmission system according to claim 1, wherein a derivation process is performed on the basis of the table.   The redundant transmission system according to any one of claims 1 to 13, wherein the transmission side device and / or the reception side device confirms normality of a communication path in an arbitrary section in a communication network. .   The redundant transmission system according to any one of claims 1 to 14, wherein a failure location is determined by a set of a transmission system number on a transmission side and a reception system number on a reception side.   16. The transmission device according to claim 1, wherein the transmission side device changes a setting relating to QoS, tunneling, and flow control attached to data to be transmitted to solve a problem in the communication path. The described redundant transmission system.   The transmission side apparatus as described in any one of Claims 1 thru | or 16.   The receiving side device according to any one of claims 1 to 16. The transmission side device takes a different communication path from a different system and assigns a sequence number to each data string to be transmitted, and sends it to a communication network that can take a plurality of communication paths in at least a duplex state to the partner device. And
The receiving device
A buffer area corresponding to each sequence number is provided, and each data transmitted from a partner device through a different communication path of the communication network is buffered in correspondence with the respective sequence number in the buffer area. While monitoring the status of the system and / or communication path based on the reception status of the path through which each data of the same content,
A redundant transmission method for a transmission system, wherein each data buffered in the buffer area is extracted in order of sequence number to restore a data string to be transmitted that has been transmitted in at least a duplex state.   20. The redundant transmission method according to claim 19, wherein the reception side apparatus switches the reception path based on a monitoring result of a system and / or a communication path state.   21. The redundant transmission method according to claim 19, wherein the reception side device notifies the transmission side of a monitoring result.   The redundant transmission method according to claim 21, wherein the reception side device notifies the transmission side device of path switching.   The receiving-side apparatus has a table for determining a problematic system and / or a location of a communication path corresponding to a reception state of a path through which each data of the same content passes, 23. The redundant transmission method according to claim 19, wherein the communication path is derived based on the table.   The redundant transmission method according to any one of claims 19 to 23, wherein the transmission side device monitors a state of a system and / or a communication path in cooperation with the reception side device.   The redundancy according to any one of claims 19 to 24, wherein the transmission side device switches a transmission circuit and / or a passage route based on a monitoring result of a state of a system and / or a communication route. Transmission method.   The redundant transmission method according to any one of claims 19 to 25, wherein the transmission side device negotiates a processing operation based on a monitoring result with the reception side device.   The transmission side device dynamically changes a path for sending each piece of data having the same content to the reception side device in correspondence with a sequence number, and sets a data string to be transmitted in a communication network at least in a duplex state. 27. The redundant transmission method according to any one of claims 19 to 26, wherein:   The transmission side device has a table for determining a problem system and / or a communication path location corresponding to a reception state of a path through which each data of the same content passes, and has a problem system 28. The redundant transmission method according to claim 19, wherein the communication path is derived based on the table.   The redundant transmission method according to any one of claims 19 to 28, wherein the transmission side device and / or the reception side device checks normality of a communication path in an arbitrary section in a communication network. .   30. The redundant transmission method according to any one of claims 19 to 29, wherein a failure location is determined by a set of a transmission system number on a transmission side and a reception system number on a reception side.

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