JP6913774B2 - Communications system - Google Patents

Description

The present invention relates to a communication system relating to signal control between a plurality of electronic devices.

Signal control communication between electronic devices, including terminal devices that drive and control a large number of on-site equipment related to railway operations such as traffic lights and turntables, and server devices that perform overall control according to operation schedules and operation information. There is a system. In this signal control communication system, a signal related to operation control of on-site equipment is periodically transmitted from the server device to the terminal device. Further, the response signal is transmitted from the terminal device that has received the signal to the server device. If an abnormality such as non-delivery or delay occurs in the transmission / reception of these signals, the railway operation is seriously affected. Therefore, this signal control communication system constantly monitors the transmission / reception of signals (for example, Patent Document 1).

In this signal control communication system, an IP address is set for each device based on the Internet Protocol (IP), and a command signal output from the server device and a response signal output from the terminal device are used as a layer 3 switch (L3SW). Some routers transmit the signal to the destination device according to the destination IP address of the signal.

Currently, communication using highly reliable TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) communication, which provides low overhead and high speed without ensuring completeness, are widely used as IP-based communication. It is used. In TCP, the MAC (Media Access Control) address and port of a specific communication destination device indicated by the IP address are specified, the transmission route to the destination device is defined, and the communication connection between the transmission / reception devices is established. Later, one-on-one communication is performed. On the other hand, in UDP, data is simply transmitted based on the IP address and port. Further, UDP is not limited to one-to-one unicast communication, and broadcast or multicast communication in which output data is transmitted to a plurality of destinations at once is possible.

Here, in IP communication between electronic devices having different IP addresses, the transmission data is transmitted with a header including the IP address of the transmission destination and a header including the MAC address of the transmission destination. If the MAC address corresponding to the IP address is unknown, an ARP (Address Resolution Protocol) command including the destination IP address is issued by broadcast from the L3SW or router, and the MAC is issued from the electronic device to which the IP address is set. By returning the address, the correspondence between the IP address and the MAC address is acquired. This correspondence is held in the ARP table in the L3SW until the predetermined expiration time elapses, and if there is communication to this electronic device again before the expiration time elapses, the ARP table is referred to. Communication data is immediately transmitted to the electronic device by the obtained MAC address, the expiration time is extended, the ARP table is kept up to date, and the frequency of issuing unnecessary ARP commands is suppressed. ..

However, when the communication of the L3SW or router fails and the switching or routing operation shifts to the backup system L3SW or the like, or when the operation returns to the main L3SW or the like restored from the backup system. , This ARP table is not retained or has been deleted, so a new APR command is issued for all communication destinations and the IP address related to the electronic device of the communication destination is displayed in the ARP table. It is necessary to re-memorize the correspondence between the MAC address and the MAC address. Therefore, it is necessary to send and receive ARP commands for all necessary correspondences, and there is a problem that communication is delayed by sending and receiving ARP commands until the ARP table is regenerated.

On the other hand, in Patent Document 2, a backup of the ARP table generated by L3SW is maintained in the memory during the occurrence of a failure of the main system, and at the time of recovery, the main ARP is sequentially performed while communicating with reference to this backup. A technology that prevents communication delays and an increase in communication load by updating the table and switching to the latest information is disclosed.

Japanese Patent No. 4948247 Japanese Patent No. 5525373

However, in order to separately store the backup of the ARP table and update the main ARP table while using the backup, it is necessary to change the configuration and operation of the L3SW, router, etc. from the conventional one, which is costly and troublesome. There is a problem that it takes.

An object of the present invention is to provide a communication system capable of suppressing an increase in load due to issuance of an ARP command while suppressing an increase in cost and labor.

In order to achieve the above object, the present invention receives communication data transmitted by broadcast from a server device and the server device at predetermined time intervals regarding the operation of the field equipment related to railway operation, and uses the field equipment. A plurality of terminal devices to be operated, a layer 3 network device connecting the server device and the plurality of terminal devices in the same LAN, and one or one connected in the same LAN via the layer 3 network device. A communication system including a plurality of electronic devices, wherein the layer 3 network device stores a table storage unit for storing correspondence data between an IP address and a MAC address, and the newly acquired correspondence data in the table storage. The plurality of terminal devices are transmitted from the server device, including a connection control unit for storing the corresponding data and erasing the corresponding data after a predetermined expiration time has elapsed after storing the corresponding data. The electronic device includes at least one of the electronic devices and an operation control unit that replies to the server device with respect to communication data including at least the contents addressed to the own device among the communication data, and the electronic device includes the plurality of said. A list storage unit that stores a list of IP addresses of the terminal devices of the above, and a plurality of the list storage units based on the list of the list storage unit before the expiration time of the corresponding data related to the plurality of terminal devices has elapsed. It was decided to include a processing device including a processing control unit that performs predetermined communication with the terminal device at different timings.
As a result, when communication between a server device and a terminal device requires direct notification to a plurality of terminal devices due to a failure of an electronic device such as a processing device that is not related to the communication itself, a large amount of ARP is performed at one time. It is not necessary to send a command, and it is possible to prevent an increase in the processing load of the layer 3 network device and the communication volume of the network. Further, since the command related to the storage and maintenance of the corresponding data of the IP address and the MAC address to the table storage unit is transmitted from the processing device to each terminal device at different timings, similarly, the processing load of the layer 3 network device. And the increase in network communication volume can be suppressed, and as a result, the communication speed between the server device and the plurality of terminal devices can be maintained. Since the load can be suppressed and the communication speed can be maintained without changing the configuration and operation of the layer 3 network device, it is possible to suppress an increase in cost and labor.
In addition, the processing control unit performs the predetermined communication with the plurality of terminal devices at time intervals obtained by dividing the time obtained by subtracting a predetermined margin from the expiration time by the number of the plurality of terminal devices.
In addition, the processing control unit performs the predetermined communication with the plurality of terminal devices at transmission intervals set so as to perform communication at different timings.

Further, the predetermined communication by the processing control unit is the issuance of a command related to ICMP_ECHO. That is, the processing control unit uses basic commands for IP connection such as an echo request (request for reachability confirmation) related to ICMP (Internet Control Message Protocol). Therefore, the amount of communication per command is small, and the processing of the terminal device that makes a reply is also small.

Further, the processing device is the same as at least one of the electronic devices. Therefore, since the server device and the terminal device are not allowed to perform such an operation, it is not necessary to suppress the increase in the processing load and increase the number of unnecessary electronic devices connected, and the cost and maintenance effort are not increased. ..

Further, at least one of the electronic devices is a monitoring device for performing processing related to monitoring of a communication abnormality between the server device and the plurality of terminal devices. Therefore, the security and certainty of communication can be maintained without significantly increasing the communication load.

Further, the server device is an interlocking device related to on-site equipment including a signal and a turnout in the station yard, and the operation control unit is connected to the own device based on the communication data addressed to the own device. It was decided to control the operation of the on-site equipment.
Therefore, when a non-delivery notification is sent from the layer 3 network device to each terminal device due to a failure of a third electronic device that is not related to the operation of the field equipment such as a monitoring device, the layer 3 network device is set in advance. By holding the corresponding data of the MAC address and IP address of each terminal device in the ARP table storage unit, it is not necessary to issue a large number of ARP commands at once, so that signals and switches that require quick processing are required. It does not cause problems such as delay in the operation of the lever.

According to the present invention, there is an effect that an increase in load due to issuance of an ARP command can be suppressed while suppressing an increase in cost and labor.

It is a block diagram which shows the embodiment of the communication system of this invention. It is a figure which shows the issuance timing of a ping command by a monitoring device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an overall configuration of a signal control communication system P in a station, which is an embodiment of the communication system of the present invention.

The signal control communication system P (communication system) includes a station device 11, an interlocking device 12 (server device), a monitoring device 13 (electronic device, processing device), a maintenance device 14, and an L3SW15 (layer 3 network device). , A plurality of terminal devices 16, a signal 17 and a turnout 18 connected to each terminal device 16, and the like.

The station device 11 includes a control unit 111, and is a signal for entering or departing a train (vehicle) at a target station, which is output from a central device (not shown) related to CTC (Centralized Traffic Control) according to operation schedule information or the like. The operation commands of 17 and the turnout 18 are acquired and output to the interlocking device 12.

The interlocking device 12 includes a control unit 121, and each operation command input from the station device 11 satisfies the logical conditions of the traffic lights 17 and the turnouts 18, so that each train or vehicle can be safely driven. After determining that it is possible, the operation command is output to the terminal device 16 via the L3SW15. Further, the interlocking device 12 prohibits an operation that does not satisfy the conditions depending on the end of the operation corresponding to the output operation command, the lapse of a predetermined time from the operation, and / or various conditions such as the position of the train or the vehicle. Lock.

The terminal device 16 determines whether or not each operation command input from the interlocking device 12 via the L3SW15 is a command addressed to the own device, and according to the command addressed to the own device, the connected traffic light 17 or the turnout An operation control unit 161 for operating the switch 18 is provided. Further, the terminal device 16 outputs a response signal indicating that the command addressed to the own device has been acquired (or indicating that the acquired command has been further executed) to the interlocking device 12 via the L3SW15.

The monitoring device 13 monitors the communication content between the interlocking device 12 and the terminal device 16, and all the operation commands output from the interlocking device 12 are normally received by the appropriate terminal device 16 and the operation is executed. Performs a predetermined process for determining whether or not. The monitoring device 13 includes a control unit 131 (processing control unit) and a terminal list 132 (list storage unit). The terminal list 132 stores and holds the IP addresses of all the terminal devices 16 connected to the interlocking device 12 and the monitoring device 13 via the L3SW15.

The maintenance device 14 includes a control unit 141, is connected to the L3SW15 as needed, and is used for work such as updating the processing software installed in the terminal device 16.

Each of the station device 11, the interlocking device 12, the monitoring device 13, the maintenance device 14, and the terminal device 16 includes a communication unit including a NIC (Network Interface Card) and the like. Each NIC has a MAC address. Further, the IP address is set and held by the control unit of each of these configurations.

The L3SW15 relays the communication exchanged between the interlocking device 12, the monitoring device 13, the maintenance device 14, and the terminal device 16 on the IP network (network layer), and outputs the communication to an appropriate destination. The L3SW15 includes an ARP table 151 (ARP table storage unit) that stores correspondence data between the IP address and the MAC address, and the control unit 152 (connection control unit) of the L3SW15 receives a request for data transmission by unicast communication. In this case, the MAC address corresponding to the IP address of the data transmission destination is confirmed by referring to the ARP table 151, and if the MAC address is stored, the header information is rewritten and output, and the MAC address is the ARP table 151. If it is not stored in, an ARP command for acquiring the MAC address corresponding to the IP address of the data transmission destination is broadcast by UDP. Further, when the control unit 152 receives a request for data transmission by broadcast communication, the control unit 152 outputs the data to all connected devices except the source of the data. The correspondence data of the IP address and the MAC address acquired by the ARP command is stored in the ARP table 151, and if the stored correspondence data is not referred to again within the predetermined expiration time after each acquisition. , Will be erased after the expiration time.

The traffic light 17 is arranged in the station yard and indicates whether or not the train or vehicle can proceed and the speed limit (deceleration, deceleration, etc.). The turnout 18 is arranged in the station yard and operates a turnout (point) for switching the traveling direction of a train or a vehicle. Each of the traffic light 17 and the turnout 18 is connected to the corresponding terminal device 16 and is maintained in an operating state according to a command input from the terminal device 16.

The interlocking device 12 includes other on-site equipment (field equipment) related to the running of trains and vehicles via L3SW15, for example, various equipment related to railroad crossings on the premises, display control devices for drivers and train users, and the like. Can be connected. Further, the interlocking device 12 is provided with various equipment for acquiring the position of the train, for example, ATS (Automatic Train Stop), ATC (Automatic Train Control) data (data from the ground element, etc.) input, track circuit, and the like. It is connected and used for determining logical conditions and locking.

Next, data transmission / reception between each configuration in the signal control communication system P of the present embodiment will be described.

In the signal control communication system P of the present embodiment, as described above, a unique IP address is assigned to each configuration, and signals are exchanged by IP connection within the broadcast domain (same LAN) via L3SW15. Will be. Among the exchanged signals, the signal (communication data) transmitted from the interlocking device 12 to each terminal device 16 and the monitoring device 13 during normal operation, that is, the operation command signal is broadcast by UDP without specifying the transmission destination. Is transmitted periodically, for example, every 50 ms.

The NIC of the terminal device 16 that has received the operation command signal takes in the operation command signal and sends it to the control unit, and each control unit operates the operation command signal to the traffic light 17 or the turnout 18 related to the own device. Judge whether it is an order or not. If it is determined that the operation command is addressed to the own device, the operation command is executed, a response is made to the UDP communication related to the operation command signal, and the operation command signal is transmitted to the interlocking device 12 and the monitoring device 13.

On the other hand, when communication related to maintenance work such as updating is performed from the maintenance device 14 to the specific terminal device 16, a TCP connection is established with the specific terminal device 16 and unicast communication is performed. Is done.

In the signal control communication system P of the present embodiment, one monitoring device 13 is sequentially used for all the terminal devices 16 at predetermined intervals (for example, every 2 seconds) while referring to the terminal list 132 (for example, every 2 seconds). A command related to ICMP_ECHO (at different timings), for example, a ping command is transmitted. By transmitting a unicast command by ICMP (Internet Control Message Protocol), which is a higher-level protocol of IP, the L3SW15 between the monitoring device 13 and the terminal device 16 to which the ping command is transmitted is the ping command. Is received, the ARP table 151 for acquiring the MAC address of the terminal device 16 corresponding to the IP address in the IP packet of the ping command is referred to. When the MAC address is not stored in the ARP table, the L3SW15 issues an ARP command by UDP, and the terminal device 16 returns, so that the MAC address of the terminal device 16 is acquired. The L3SW 15 transmits the MAC frame data related to the ping command addressed to the acquired MAC address to the terminal device 16, and registers the correspondence between the IP address and the MAC address of the terminal device 16 in the ARP table 151.
At this time, by setting the transmission interval so that the transmission interval of the ping to the predetermined terminal device 16 is equal to or less than the expiration time of the ARP table 151, the MAC address once stored in the ARP table 151 is not erased. It is possible to eliminate the need to issue the ARP command from the second time onward.

FIG. 2 is a chart showing the issuance timing of the ping command by the monitoring device 13.
The monitoring device 13 sequentially transmits a ping command to each terminal device 16 so that the correspondence between the IP address and the MAC address of all the terminal devices 16 is stored in the ARP table 151. That is, the ping command issuance interval by the monitoring device 13 is set to a time obtained by dividing the time obtained by subtracting a predetermined margin from the expiration time of the ARP table 151 in the L3SW15 by the number of terminal devices 16, so that the ping command is used. The correspondence between the IP address and the MAC address of all the terminal devices 16 continues to be stored in the ARP table 151 while minimizing the increase in traffic in the network and the increase in the load on the L3SW15. Therefore, the ping command is immediately transmitted to each terminal device 16 according to the ARP table 151, and the ARP command is not issued.

When the number of terminal devices 16 is sufficiently smaller than the expiration time of the ARP table 151, the ping command does not necessarily have to be issued at equal time intervals, resulting in an increase in traffic and an increase in the load on the L3SW15. Issuance of the next ping command to each terminal device 16 until a predetermined time equal to or less than the expiration time of the ARP table 151 elapses after issuing the ping command to all the terminal devices 16 at time intervals within a range that does not adversely affect May be canceled.

In this situation, if an abnormality occurs in the communication path between the monitoring device 13 or L3SW15 and the monitoring device 13 and the response of the input command from each terminal device 16 does not reach the monitoring device 13, the L3SW15 will change to each terminal device 16. The ICMP notification regarding the non-delivery of the destination is given to each of the recipients. At this time, since all the correspondence between the MAC address and the IP address of each terminal device 16 is stored in the ARP table 151, the control unit 152 of the L3SW 15 refers to the ARP table 151 without issuing an ARP command. For the terminal device 16, the destination MAC address and the destination IP address in the header are set, and the ICMP notification is transmitted.

As described above, the signal control communication system P of the present embodiment includes the interlocking device 12, a plurality of terminal devices 16 that receive communication data transmitted by broadcast from the interlocking device 12, the interlocking device 12, and the plurality of terminal devices. Signal control communication including L3SW15 connecting 16 in the same LAN and one or more electronic devices such as an interlocking device 12 and a monitoring device 13 connected in the same LAN as the terminal device 16 via L3SW15. In the system P, the L3SW 15 stores the ARP table 151 for storing the correspondence data between the IP address and the MAC address and the newly acquired correspondence data in the ARP table 151, and after the correspondence data is stored. A control unit 152 for erasing the corresponding data after a predetermined expiration time has elapsed, and the plurality of terminal devices 16 are provided with the interlocking device 12 for communication data including at least the contents addressed to the own device from the interlocking device 12. A terminal list 132 that stores a list of IP addresses of a plurality of terminal devices 16 and an IP address related to the plurality of terminal devices 16 are provided in the electronic device, including an operation control unit 161 that returns a reply to the monitoring device 13. Before the expiration time of the corresponding data of the MAC address and the MAC address elapses, a ping command is transmitted to each of the plurality of terminal devices 16 at different timings based on the list of the terminal devices 16 stored in the terminal list 132. A monitoring device 13 including a control unit 131 is included.
That is, with respect to the communication between the interlocking device 12 and the terminal device 16 in which communication is performed by broadcast by UDP in order to maintain high-speed communication, a plurality of terminals are caused by a failure of the monitoring device 13 which is not related to the communication itself. By generating and maintaining the ARP table 151 in advance when direct notification is required to the device 16, it is not necessary to send an ARP command, and the processing load of L3SW15 and network communication due to unintended mass issuance of ARP It is possible to prevent an increase in the amount. Further, since the command related to the generation and maintenance of the ARP table 151 is managed so as to be transmitted from the monitoring device 13 to each terminal device 16 at different timings, the L3SW15 also generates and maintains the ARP table 151. It is possible to suppress an increase in processing load and network communication volume, and as a result, it is possible to maintain the communication speed between the interlocking device 12 and the plurality of terminal devices 16. Further, since the ping is transmitted from one monitoring device 13 to each terminal device 16, operation management for shifting the transmission timing can be easily performed. Since the load can be suppressed and the communication speed can be maintained without changing the configuration and processing of the L3SW15, it is possible to suppress an increase in cost and labor.

Further, since the monitoring device 13 transmits a command related to ICMP_ECHO, particularly ping, the amount of communication per command is small, and the processing of the terminal device 16 for replying is also small, so that a large load is not generated.

Further, since the monitoring device 13 collectively transmits pings to each terminal device 16, the best command transmission is performed so that the processing load of the L3SW 15 and the network load between the interlocking device 12 and each terminal device 16 do not increase. The interval can be easily set.
Further, since the interlocking device 12 is not allowed to perform such an operation, the processing load of the interlocking device 12 is not increased, and the interlocking device 12 can more reliably output an operation command related to signal control at an appropriate timing. You can.
Further, since the device used for the monitoring device 13 has been used for both the ping transmission operation and the timing control thereof, it is not necessary to increase the number of unnecessary electronic devices connected, and the cost and maintenance effort are not increased.

Further, since the monitoring device 13 is connected inside the LAN including the interlocking device 12 and the plurality of terminal devices 16 and the increase in the load related to the communication abnormality to the monitoring device 13 is suppressed, the communication load is greatly increased. It is possible to maintain the security and certainty of communication without having to do so. In particular, it is possible to easily achieve both a reduction in communication overhead by using UDP communication and a response to a decrease in communication security.

Further, in particular, a signal is transmitted between the interlocking device 12 related to the operation control of the on-site equipment including the signal 17 and the turning device 18 in the station yard and the terminal device 16 that actually controls the operation of these on-site equipment. In such a case, when a non-delivery notification is sent from the L3SW15 to each terminal device 16 due to a failure of a third electronic device such as the monitoring device 13 which is not related to the operation of the on-site equipment, the L3SW15 sets the ARP table in advance. By maintaining the correspondence between the MAC address and IP address of each terminal device 16, it is not necessary to issue a large number of ARP commands at one time. It does not cause problems such as delay in the operation of the lever 18.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, ping has been described as a command related to ICMP_ECHO, but other commands such as tracert (traceroute) may be used, and other unicast commands that require address resolution for transmission may be used. Other commands may be used as long as the processing load is sufficiently small.

Further, the L3SW15 may be a router as long as each configuration is provided in the same LAN, that is, within the reachable range of the broadcast message.

Further, in the above embodiment, both the non-delivery target of the signal and the issuance of the ping command are performed from the monitoring device 13, but it is possible to store the list of IP addresses of the terminal device 16. If there is a computer or the like connected to the L3SW15 for a period of time that does not affect the issuance of the ping command to all the terminal devices 16, the ping command may be issued from the computer.

Further, the device for which a response is input from each terminal device 16 is not limited to the monitoring device 13. It may be another information processing device that organizes and processes the input response data. Further, the monitoring device 13 and the information processing device provided in the same LAN are not limited to one, and may be a plurality of. In this case, the device for which the response is input from each terminal device 16 and the device for transmitting the ping to each terminal device 16 may be different.

Further, in the above embodiment, the signal control communication system P related to the operation control of the traffic light 17 and the turning device 18 in the station yard has been described, but the signal control system related to the crossing between stations, the turning device and the blockage signal has been described. The present invention may be applied to the above, and further, it may be applied to any system that performs the same communication control.
In addition, specific details such as the configuration, arrangement, circuit, and processing procedure shown in the above embodiment can be appropriately changed without departing from the spirit of the present invention.

11 Station device 111 Control unit 12 Interlocking device 121 Control unit 13 Monitoring device 131 Control unit 132 Terminal list 14 Maintenance device 141 Control unit 15 L3SW
151 ARP table 152 Control unit 16 Terminal device 161 Operation control unit 17 Traffic light 18 Turnout P Signal control communication system

Claims (7)

With the server device
A plurality of terminal devices that receive communication data transmitted by broadcast from the server device at predetermined time intervals regarding the operation of the on-site equipment related to railway operation, and operate the on-site equipment.
A layer 3 network device that connects the server device and the plurality of terminal devices in the same LAN, and
With one or more electronic devices connected in the same LAN via the layer 3 network device,
It is a communication system equipped with
The layer 3 network device is
A table storage unit that stores the corresponding data between the IP address and the MAC address,
A connection control unit that stores the newly acquired corresponding data in the table storage unit and erases the corresponding data after a predetermined expiration time has elapsed since the corresponding data was stored.
With
The plurality of terminal devices reply to at least one of the electronic devices and the server device in response to communication data including at least the content addressed to the own device among the communication data transmitted from the server device. Equipped with an operation control unit
The electronic device
A list storage unit that stores a list of IP addresses of the plurality of terminal devices,
Processing control for performing predetermined communication to the plurality of terminal devices at different timings based on the list in the list storage unit before the expiration time of the corresponding data related to the plurality of terminal devices has elapsed. Department and
A communication system comprising a processing device comprising. The processing control unit is characterized in that the processing control unit performs the predetermined communication with the plurality of terminal devices at time intervals obtained by dividing the time obtained by subtracting a predetermined margin from the expiration time by the number of the plurality of terminal devices. The communication system according to claim 1. The communication system according to claim 1 or 2, wherein the processing control unit performs the predetermined communication with the plurality of terminal devices at transmission intervals set to perform communication at different timings. .. The communication system according to any one of claims 1 to 3, wherein the predetermined communication by the processing control unit is issuance of a command related to ICMP_ECHO. The communication system according to any one of claims 1 to 4, wherein the processing device is the same as at least one of the electronic devices. Claims 1 to 5 , wherein at least one of the electronic devices is a monitoring device for performing processing related to monitoring of a communication abnormality between the server device and the plurality of terminal devices. The communication system according to any one item. The server device is an interlocking device related to on-site equipment including a traffic light and a turnout in a station yard.
The operation of any one of claims 1 to 6 , wherein the operation control unit controls the operation of the field equipment connected to the own device based on the communication data addressed to the own device. Communications system.

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