JP2017216563A - Repeating device, control method, and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repeating device in which precision of time synchronization of a slave device is not deteriorated, upon occurrence of failure in the repeating device interposed between a master device and the slave device.SOLUTION: A repeating device 10 has a reception unit 11 for receiving a first synchronous packet containing time information from a mater device 20, a time information processing unit 14 for generating second synchronous packet containing time information indicating the delay time occurred in the own device based on the first synchronous packet, a failure detector 12 for monitoring whether or not the failure has occurred in the own device, a transmission unit 15 for transmitting the second synchronous packet to a slave device 30, when the failure has not occurred, and an abnormal time processing unit 13 executing abnormal time processing onto the second synchronous packet when the failure has occurred.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a relay apparatus, a control method, and a communication system, for example, a relay apparatus, a control method, and a communication system that transmit synchronization information via a network.

  GNSS (Global Navigation Satellite System) receivers receive signals (synchronization signals) broadcast from GNSS satellites when performing time synchronization required when using GPS (Global Positioning System), etc. To do. The GNSS receiver can output a timing signal synchronized with UTC (Coordinated Universal Time) by using a synchronization signal broadcast from a GNSS satellite.

  Further, in order to use the synchronization signal even in a communication device that exists in a place where the synchronization signal cannot be directly received from the GNSS satellite, the GNSS receiver that has received the synchronization signal from the GNSS satellite transmits the synchronization signal to the communication device via the packet network. May be sent.

  However, the synchronization signal transmitted through the packet network has a transmission delay. In addition, the transmission delay value fluctuates depending on traffic conditions in the packet network. For this reason, the communication apparatus needs to use a synchronization signal in consideration of a transmission delay that occurs in the packet network.

  Here, in the IEEE1588v2 (IEEE1588-2008) network defined to execute phase synchronization using packet data (synchronization packet), in order to reduce the transmission delay of the transmission device and the relay device constituting the network The use of a transparent clock device as a synchronization device is specified. The transparent clock device receives a synchronization packet (Ingress packet) from the master device. Then, the transparent clock device processes the synchronization packet so as to write in the correction field of the received synchronization packet the time when the synchronization packet stayed in the transparent clock device. Specifically, the transparent clock device updates the correction field of the synchronization packet. Then, the transparent clock device transmits the processed synchronization packet (egress packet) to the slave communication device. The synchronization packet defined by IEEE1588-2008 is a precision time protocol (PTP) packet. The correction field defined in IEEE 1588-2008 is correctionField.

  Patent Document 1 discloses a configuration of a hierarchical communication system having a master device, a relay slave device, and a terminal slave device. Patent Document 1 discloses a process that does not degrade the accuracy of time synchronization even when a failure occurs in the master device. Specifically, Patent Document 1 discloses the following processing.

  The master device and the relay slave device transmit and receive Sync messages, Announce messages, and the like. When a failure occurs in the master device, the master device transmits an Announce message having failure information to the relay slave device. When the relay slave device receives the Announce message having the failure information, the relay slave device does not use the time information transmitted from the master device for the time synchronization processing. The relay slave device uses time information transmitted from a master device different from the master device in which the failure has occurred for time synchronization processing.

JP2015-216438A

  By the way, Patent Document 1 does not disclose processing when a failure occurs in a transparent clock device in a communication system in which a transparent clock device is arranged as a relay device between a master device and a relay slave device. As a result, for example, when a failure occurs in the Transparent Clock device, the Announce message transmitted from the master device is generated in the Transparent Clock device even if the failure process disclosed in Patent Document 1 is executed. It does not contain information about disabilities. The reason is that the Transparent Clock device updates the correction field of the synchronization packet, but sets its own failure information in the Announce message and does not send an Annunce message to the relay slave device. Therefore, the relay slave device cannot detect the failure of the transparent clock device.

  Therefore, in the communication system described in Patent Document 1, even if some failure occurs in the transparent clock device that is a relay device, the relay slave device transmits the synchronization packet received from the failed transparent clock device, Used for time synchronization processing. In such a case, the transparent clock device in which the failure has occurred may not have properly updated the correction field of the synchronization packet. Therefore, when a failure occurs in the transparent clock device, the accuracy of time synchronization in the relay slave device may deteriorate.

  Therefore, an object of the present invention is to provide a relay device that can reduce deterioration in time synchronization accuracy in a slave device even when a failure occurs in the relay device arranged between the master device and the slave device. A control method and a communication system are provided.

  The relay device according to the first aspect of the present invention includes: a receiving unit that receives a first synchronization packet including time information from a master device; and a delay time generated in the device based on the first synchronization packet. A time information processing unit that generates a second synchronization packet including time information indicating a failure, a failure detection unit that monitors whether or not a failure that has occurred in the device itself, and a failure has not occurred A transmission unit that transmits the second synchronization packet to the slave device, and an abnormal time processing unit that executes processing for an abnormal time on the second synchronization packet when a failure occurs, It is what has.

  In the control method in the relay device according to the second aspect of the present invention, the first synchronization packet including the time information is received from the master device, and the delay time generated in the own device based on the first synchronization packet. And generates a second synchronization packet including time information indicating whether or not a failure has occurred in the device itself. If no failure has occurred, the second synchronization packet is transmitted to the slave device. When a failure occurs, an abnormal process is executed on the second synchronization packet.

  A communication system according to a third aspect of the present invention is a communication system including a master device, a slave device, and a relay device disposed between the master device and the slave device, wherein the relay device is a master device. A reception unit that receives a first synchronization packet including time information from the device, and generates a second synchronization packet that includes time information indicating a delay time generated within the device based on the first synchronization packet. A time information processing unit, a failure detection unit that monitors whether or not a failure has occurred in the device itself, and if no failure has occurred, the second synchronization packet is transmitted to the slave device. A transmission unit; and an abnormality processing unit that executes an abnormality processing for the second synchronization packet when a failure occurs.

  The present invention provides a relay device, a control method, and a communication system that do not deteriorate the accuracy of time synchronization in a slave device when a failure occurs in a relay device arranged between a master device and a slave device. Can do.

1 is a configuration diagram of a relay device according to a first embodiment; FIG. 3 is a configuration diagram of a communication system according to a second exemplary embodiment. It is a block diagram of the relay apparatus concerning Embodiment 2. FIG. FIG. 10 is a diagram illustrating a flow of failure detection processing in the relay device according to the second embodiment. FIG. 6 is a configuration diagram of a relay device according to a third embodiment. FIG. 10 is a diagram illustrating a flow of failure detection processing in the relay device according to the third embodiment; .

(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings. First, a configuration example of the relay apparatus 10 according to the first embodiment will be described with reference to FIG. The relay device 10 is disposed between the master device 20 and the slave device 30. Furthermore, the relay apparatus 10 has a Transparent Clock function. The transparent clock function is a function for writing the time that the synchronization packet stays in the relay apparatus 10 in the correction field in the synchronization packet. The slave device 30 synchronizes its own clock with the clock of the master device 20 using the synchronization packet received via the relay device 10. The master device 20 and the slave device 30 perform time synchronization using PTP (Precision Time Protocol). The relay device 10 may include a dedicated circuit that functions in this way. Further, the relay device 10 may be a computer device that operates by logically providing such a function by executing a program stored in or read from a memory built in a built-in processor. Good.

  More specifically, the relay device 10 includes a reception unit 11, a failure detection unit 12, an abnormality processing unit 13, a time information processing unit 14, and a transmission unit 15. The components constituting the relay device 10 such as the reception unit 11, the failure detection unit 12, the abnormal time processing unit 13, the time information processing unit 14, and the transmission unit 15 execute a program stored in the memory by the processor. It may be software or a module that executes processing according to the above. Or the component which comprises the relay apparatus 10 may be hardware, such as a chip | tip or a circuit.

  The receiving unit 11 receives a synchronization packet used for phase synchronization and time synchronization from the master device 20. Here, in the IEEE 1588v2 (IEEE 1588-2008) network, a synchronization packet (Ingress packet) used for phase synchronization and time synchronization is a PTP packet. The time information processing unit 14 writes the above-mentioned dwell time in the device, that is, time information indicating the delay time in its own device, into the synchronization packet (Ingress packet) received by the receiving unit 11 from the master device 20, and creates a new A synchronization packet (Engress packet) is generated. Then, the transmission unit 15 transmits the newly generated synchronization packet to the slave device 30.

  The failure detection unit 12 detects a failure that has occurred in the relay device 10. For example, the failure detection unit 12 periodically outputs a signal to each component constituting the relay device 10 and determines whether or not a failure has occurred in the relay device 10 depending on whether a response signal has been received. May be detected or determined. As another example, the failure detection unit 12 may detect or determine an abnormal operation of the transparent clock function. Specifically, the failure detection unit 12 determines that the transparent clock function is operating normally when the time that the synchronization packet stays in the relay device 10 is within a predetermined time range, If the predetermined time is exceeded, it is determined that the transparent clock function is not operating normally. Alternatively, the failure detection unit 12 has a difference between the time corrected using the correction value set in the correction field of the synchronization packet and the time when the reception unit 11 receives the synchronization packet within a predetermined range. Whether or not the transparent clock function is operating normally may be determined depending on whether or not the transparent clock function is operating normally.

  When a failure is detected by the failure detection unit 12, the abnormal time processing unit 13 performs clock quality in the slave device 30 that is a transmission destination of the synchronization packet (Egress packet), that is, synchronization between the master device 20 and the slave device 30. Execute the process at the time of abnormality so as not to reduce the accuracy. For example, the processing at the time of abnormality executed by the abnormality processing unit 13 is that the relay device 10 transmits a synchronization packet (Egress packet) in which information indicating a failure of the relay device 10 is set from the transmission unit 15 to the slave device 30. It may be. Alternatively, the abnormal time process may be that the relay apparatus 10 in which the failure has occurred does not transmit the synchronization packet from the transmission unit 15 to the slave apparatus 30.

  As described above, by using the relay device 10 of FIG. 1, the relay device 10 executes the abnormal process so that the clock quality in the slave device 30 does not deteriorate when a failure occurs in the own device. Can do. In other words, when the relay device 10 notifies the slave device 30 that a failure has occurred in the relay device 10, the slave device 30 uses the synchronization packet received via the relay device in which no failure has occurred. Corresponding processing such as clock synchronization can be executed.

(Embodiment 2)
Then, the structural example of the communication system which concerns on Embodiment 2 of this invention using FIG. 2 is demonstrated. 2 includes a GNSS (Global Navigation Satellite System) satellite 40, a GNSS receiver 50, a master device 20, a master device 25, a relay device 10, a relay device 17, a relay device 18, and a slave. A device 30 is included.

  The GNSS satellite 40 transmits a GNSS broadcast signal synchronized with UTC (Coordinated Universal Time). GNSS is a general term for satellite positioning systems including GPS, GLONASS, Galileo, Compass, or Quasi-Zenith Satellite (QZSS). The GNSS receiver 50 receives a GNSS broadcast signal transmitted from the GNSS satellite 40. The GNSS receiver 50 reproduces a synchronization signal based on the GNSS broadcast signal, and transmits the reproduced synchronization signal to the master device 20 and the master device 25. Alternatively, the function in the GNSS receiver 50 and the function in the master device 20 may be incorporated in the same device.

  The master device 20 transmits a synchronization packet to the slave device 30 via the relay device 10. Further, the master device 20 transmits a synchronization packet to the slave device 30 via the relay device 18. The master device 25 transmits a synchronization packet to the slave device 30 via the relay device 17. The synchronization packet is, for example, a clock signal generated using a GNSS broadcast signal. Here, the master device 20 transmits a synchronization signal using, for example, a method defined in IEEE 1588 (hereinafter referred to as IEEE 1588 transmission) or a Synchronous Ethernet (registered trademark) (hereinafter referred to as SyncE) method. IEEE 1588 transmission and SyncE transmission are performed via Ethernet (registered trademark). IEEE 1588 may also be referred to as PTP (Precision Time Protocol). The system defined in IEEE 1588 includes an updated version such as IEEE 1588 Version 2 (IEEE 1588-2008).

  The relay device 10, the relay device 17, and the relay device 18 are devices arranged in a packet network that transmits packet data via, for example, Ethernet or a wireless communication network. In FIG. 2, it is shown that the slave device 30 receives a synchronization packet using a route passing through the relay device 10, a route passing through the relay device 18, and a route passing through the relay device 17. The device 30 may receive a synchronization packet using four or more routes. In addition, FIG. 2 shows that only one relay device is arranged for one route, but the slave device 30 receives a synchronization packet via a plurality of relay devices in one route. Also good.

  The relay device 10 and the relay device 18 receive the synchronization packet transmitted from the master device 20. The relay device 17 receives the synchronization packet transmitted from the master device 25. Further, the relay device 10, the relay device 17, and the relay device 18 reflect their own data processing time in the time correction field of the synchronization packet. That is, the relay device 10, the relay device 17, and the relay device 18 update the time correction field of the synchronization packet. Reflecting the data processing time of the own device in the time correction field of the synchronous packet is called a transparent clock function. The relay device 10, the relay device 17, and the relay device 18 transmit the synchronization packet with the updated time correction field to the slave device 30. When a plurality of relay devices are connected in series, for example, the relay device 10 may receive a synchronization packet transmitted from another relay device, and the relay device 10 is updated to another relay device. The synchronized packet may be transmitted.

  The slave device 30 receives the synchronization packet transmitted via the relay device 10, the synchronization packet transmitted via the relay device 17, and the synchronization packet transmitted via the relay device 18. Further, the slave device 30 selects any one of the synchronization packet transmitted via the relay device 10, the synchronization packet transmitted via the relay device 17, and the synchronization packet transmitted via the relay device 18. . The slave device 30 uses the selected synchronization packet to generate synchronization time information that is synchronized with the time information generated in the GNSS receiver 50, the master device 20, or the like. Generation of the synchronization time information may use a method defined in the above-described IEEE 1588 or the like, or may use another method.

  For example, the slave device 30 may select one synchronization packet from among a plurality of synchronization packets using information on the priority set in the synchronization packet. For example, the slave device 30 selects a synchronization packet with a high priority.

  Here, an operation when a failure occurs in the master device 20 will be described. It is assumed that the slave device 30 performs time synchronization using the synchronization packet transmitted from the master device 20.

  When a failure occurs in the master device 20, the master device 20 transmits a PTP message including information indicating that the device itself is not operating normally to the slave device 30. The PTP message is transmitted from the master device 20 to the slave device 30 via the relay device 10 and the relay device 18. The PTP message including information indicating that the master device 20 is not operating normally may be, for example, an announce message transmitted / received in time synchronization processing using PTP.

  When the slave device 30 receives an announce message including information indicating that the master device 20 is not operating normally, the slave device 30 does not perform time synchronization using the synchronization packet transmitted from the master device 20. In other words, when receiving an announce message including information indicating that the master device 20 is not operating normally, the slave device 30 performs time synchronization using the synchronization packet transmitted from the master device 25.

  Next, an operation when a failure occurs in the relay device 10 will be described. Assume that the slave device 30 performs time synchronization using a synchronization packet transmitted from the master device 20 via the relay device 10.

  The relay device 10 relays the announce message transmitted from the master device 20 to the slave device 30. Since no failure has occurred in the master device 20, the announce message includes information indicating that the master device 20 is operating normally. Therefore, when the relay device 10 in which the failure has occurred transmits the announce message transmitted from the master device 20 to the slave device 30, the slave device 30 executes time synchronization processing using the synchronization packet received from the relay device 10. .

  For example, there is a possibility that the correct value is not set in the correction field of the synchronization packet transmitted from the relay apparatus 10 in which the failure has occurred. Alternatively, there is a possibility that a correct value is not set in the time information of the synchronization packet transmitted from the relay apparatus 10 in which the failure has occurred. Therefore, when the slave device 30 executes the time synchronization process using the synchronization packet transmitted from the relay device 10, the time synchronization may not be performed normally.

  Therefore, the relay device 10 in which the failure has occurred changes or updates the priority value set in the header part or payload of the announce message to a low priority value. For example, the relay device 10 may be changed to a value indicating that the priority is the lowest among the values that can be set.

  When the slave device 30 receives an announce message with a low priority from the relay device 10, the slave device 30 performs time synchronization processing using a synchronization packet transmitted from another relay device instead of the synchronization packet transmitted from the relay device 10. Change the time synchronization process to do.

  Next, a configuration example of the relay apparatus 10 according to the second embodiment will be described with reference to FIG. The relay device 10 includes a packet input / output unit 61, a packet processing unit 62, a PEC (Packet based Equipment Clocks) slave unit 63, a time source clock unit 64, a time selection unit 65, a time and frequency generation unit 66, a frequency selection unit 67, A packet processing unit 68, a time service monitoring unit 69, and a packet input / output unit 70 are included. The components such as the packet input / output unit 61 constituting the relay device 10 may be a computer device that operates when a processor executes a program stored in a memory. Or the component which comprises the relay apparatus 10 may be hardware, such as a chip | tip or a circuit.

  The packet input / output unit 61 transmits and receives PTP packets to and from the master device 20. The packet input / output unit 61 outputs the PTP packet received from the master device 20 to the packet processing unit 62. Further, the packet input / output unit 61 receives from the packet processing unit 62 a PTP packet to be transmitted to the master device 20. When another relay device is arranged between the relay device 10 and the master device 20, the packet input / output unit 61 transmits / receives a PTP packet to / from another relay device.

  The packet input / output unit 70 transmits and receives PTP packets to and from the slave device 30. The packet input / output unit 70 outputs the PTP packet received from the slave device 30 to the packet processing unit 68. Further, the packet input / output unit 61 receives from the packet processing unit 68 a PTP packet to be transmitted to the slave device 30. When another relay device is arranged between the relay device 10 and the slave device 30, the packet input / output unit 70 transmits / receives a PTP packet to / from another relay device.

  The packet processing unit 62 extracts a time stamp from a PTP packet (hereinafter referred to as an ingress PTP packet) transmitted from the master device 20 via the packet input / output unit 61. The packet processing unit 62 outputs the extracted time stamp to the PEC slave unit 63. For example, the time stamp may indicate a time at which the master device 20 transmits an ingress PTP packet.

  The time source clock unit 64 is a clock source that is synchronized with a time reference such as GNSS, eLORAN, 1PPS, and ToD. The time source clock unit 64 outputs the time reference or time information synchronized with the time reference to the time selection unit 65 and the PEC slave unit 63. The time source clock unit 6464 outputs the frequency information generated by using the time reference or the frequency reference (frequency reference) to the frequency selection unit 67. The time source clock unit 64 cannot always receive a time reference from GNSS or the like, and there is a timing at which the time reference cannot be received. Further, there may be no time source clock unit 64 itself. In this case, the time selection unit 65 is unnecessary, and the time information output from the PEC slave unit is input to the time and frequency generation unit 66.

  The PEC slave unit 63 corrects the time stamp received from the packet processing unit 62 using the time reference received from the time source clock unit 64. In other words, the PEC slave unit 63 compensates for the time lag of the time stamp received from the packet processing unit 62 using the time reference received from the time source clock unit 64. The PEC slave unit 63 transmits the corrected time stamp to the time selection unit 65 as time information. Further, the PEC slave unit 63 outputs the frequency information generated using the time stamp received from the packet processing unit 62 and the time reference received from the time source clock unit 64 to the frequency selection unit 67.

  The time selection unit 65 selects time information used in the packet processing unit 62, the packet processing unit 68, and the like from the time information output from at least one of the time source clock unit 64 and the PEC slave unit 63. That is, the time selection unit 65 selects a clock time source used in the relay apparatus 10. The time selection unit 65 outputs the selected time information to the time and frequency generation unit 66. For example, the time selection unit 65 preferentially selects the time information output from the time source clock unit 64, and the time output from the PEC slave unit 63 when the time information is not received from the time source clock unit 64. Information may be selected. Alternatively, when a plurality of time references such as GNSS, eLORAN, 1PPS, and ToD are output from the time source clock unit 64, the time selection unit 65 may select one time reference according to a predetermined priority order. Good. Alternatively, the time selection unit 65 may generate time information by combining a plurality of time information or a plurality of time references.

  The frequency selection unit 67 selects frequency information used in the packet processing unit 62 and the packet processing unit 68 from the frequency information output from at least one of the time source clock unit 64 and the PEC slave unit 63.

  The time and frequency generation unit 66 uses the time information output from the time selection unit 65 and the frequency information output from the frequency selection unit 67 to generate a time scale of the clock used in the relay device 10. .

  The packet processing unit 68 generates a PTP packet (hereinafter referred to as an egress PTP packet) to be transmitted to the slave device 30 via the packet input / output unit 70. Alternatively, the packet processing unit 68 may generate an egress PTP packet by updating the correction field or priority information of the ingress PTP packet output from the packet processing unit 62.

  The time service monitoring unit 69 monitors whether or not a function related to the clock in the relay apparatus 10 is operating normally. For example, the time service monitoring unit 69 may determine whether or not the transparent clock function is operating normally by analyzing time stamps output from the packet processing unit 62 and the packet processing unit 68. Alternatively, the time service monitoring unit 69 determines whether or not the transparent clock function is operating normally by analyzing the time information or correction field of the PTP packet output from the packet processing unit 62 and the packet processing unit 68. May be. When the time service monitoring unit 69 determines that the function related to the clock in the relay apparatus 10 is not operating normally, the time service monitoring unit 69 instructs the packet processing unit 68 to lower the priority of the egress PTP packet. To do.

  When instructed to lower the priority of the egress PTP packet, the packet processing unit 68 transmits the egress PTP packet updated with a lower priority value to the slave device 30 via the packet input / output unit 70. The egress PTP packet may be transmitted to the slave device 30 as, for example, a Sync message or an announce message.

  For example, when the priority of the PTP packet transmitted from the relay device 10 is lower than the PTP packet transmitted from the relay device 18 and the PTP packet transmitted from the relay device 17, the slave device 30 transmits from the relay device 18. The time synchronization is performed using the received PTP packet or the PTP packet transmitted from the relay device 17.

  Next, a flow of failure detection processing in the relay apparatus 10 according to the second embodiment will be described with reference to FIG. First, the time service monitoring unit 69 detects that the function related to the clock in the relay apparatus 10 is not operating normally, that is, that the function related to the clock in the relay apparatus 10 has failed. (S11).

  Next, the time service monitoring unit 69 outputs an instruction message instructing the packet processing unit 68 to change the clock priority set in the PTP packet (S12). The clock priority is information indicating the priority of the PTP packet. The information indicating the priority of the PTP packet corresponds to information indicating the priority of a Syn message or an announce message relayed by the relay apparatus 10. The clock priority may be set in the header of the PTP packet or may be set in the payload of the PTP packet. For example, the clock priority may indicate a plurality of levels such as a high priority, a medium priority, and a low priority. Alternatively, the clock priority may indicate detailed priority levels of four or more levels.

  For example, the time service monitoring unit 69 may instruct to set a priority level that is one step or two steps lower than the currently set priority level as a value to be set for the clock priority. Alternatively, the time service monitoring unit 69 may instruct to set the lowest priority level as the value to be set for the clock priority.

  Next, the packet processing unit 68 transmits the PTP packet after changing the clock priority to the slave device 30 (S13).

  As described above, by using the relay device 10 according to the second embodiment, when a failure occurs in the relay device 10, the slave device can reduce the priority level indicated by the clock priority of the PTP packet. 30 can notify the abnormal state of the relay device 10. When the slave device 30 receives a PTP packet having a low priority level in a state in which time synchronization processing is performed using the PTP packet transmitted from the relay device 10, the slave device 30 receives the PTP packet transmitted from another relay device. Time synchronization processing can be performed.

  As a result, the slave device 30 is a relay device in which no failure has occurred as a PTP packet used for the time synchronization process not only when a failure occurs in the master device 20 but also when a failure occurs in the relay device 10. PTP packets received from can be used.

(Embodiment 3)
Next, a configuration example of the relay device 80 according to the third embodiment will be described with reference to FIG. The relay device 80 has a configuration in which the packet processing unit 68 of the relay device 10 in FIG. Since the configuration other than the packet processing unit 68 in the relay device 80 is the same as that of the relay device 10 in FIG. 3, detailed description thereof is omitted. Further, the communication system according to the third embodiment has a configuration in which the relay device 10 in the communication system of FIG.

  When the time service monitoring unit 69 detects that a failure has occurred in a function related to the clock in the relay device 80, the time service monitoring unit 69 outputs a failure message regarding failure detection to the packet processing unit 68.

  When receiving the failure message, the packet processing unit 68 stops outputting the PTP packet to the packet input / output unit 70 using the packet filter 71. Specifically, when receiving the failure message, the packet processing unit 68 stops outputting the egress PTP packet to the packet input / output unit 70 using the packet filter 71.

  Next, a flow of failure detection processing in the relay device 80 according to the third embodiment will be described with reference to FIG. First, the time service monitoring unit 69 detects that the function related to the clock in the relay device 80 is not operating normally, that is, that a failure has occurred in the function related to the clock in the relay device 80. (S21).

  Next, the time service monitoring unit 69 outputs failure information indicating that a failure has occurred in a function related to the clock in the relay device 80 to the packet processing unit 68 to the time service monitoring unit 69 (S22). .

  Next, the packet processing unit 68 stops outputting the PTP packet to the packet input / output unit 70 using the packet filter 71.

  As described above, the relay device 80 according to the third embodiment can stop transmitting the PTP packet to the slave device 30 when a failure occurs. The slave device 30 can perform the time synchronization process using the PTP packet received from another relay device because the PTP packet is not transmitted from the relay device 80 for a predetermined period.

  In other words, when the relay device 80 does not transmit a PTP packet to the slave device 30 when a failure occurs, the slave device 30 can detect that the relay device 80 has failed.

  As a result, the slave device 30 is a relay device in which no failure occurs as a PTP packet used for the time synchronization process even when a failure occurs in the relay device 80 other than when a failure occurs in the master device 20. PTP packets received from can be used.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. Further, the present invention may be implemented by combining the above-described embodiments.

DESCRIPTION OF SYMBOLS 10 Relay apparatus 11 Receiving part 12 Failure detection part 13 Abnormal time processing part 14 Time information processing part 15 Transmission part 17 Relay apparatus 18 Relay apparatus 20 Master apparatus 25 Master apparatus 30 Slave apparatus 40 GNSS satellite 50 GNSS receiver 61 Packet input / output part 62 packet processing unit 63 PEC slave unit 64 time source clock unit 65 time selection unit 66 time and frequency generation unit 67 frequency selection unit 68 packet processing unit 69 time service monitoring unit 70 packet input / output unit 71 packet filter 80 relay device

Claims (8)

A receiver for receiving a first synchronization packet including time information from the master device;
A time information processing unit for generating a second synchronization packet including time information indicating a delay time generated in the device based on the first synchronization packet;
A failure detection unit that monitors whether or not a failure that occurred in the device itself has occurred;
If no failure has occurred, a transmitter that transmits the second synchronization packet to the slave device;
A relay apparatus comprising: an abnormal time processing unit that executes an abnormal time process on the second synchronization packet when a failure occurs.   When a failure is detected in the own device, the abnormal time processing unit transmits the second synchronization packet with a lowered priority to the slave device, and the priority is determined by the slave device with a plurality of synchronization packets. The relay device according to claim 1, which is used for selecting a synchronization packet to be used upon reception. A first packet processing unit that extracts time information from the first synchronization packet received by the receiving unit;
A second packet processing unit that generates the second synchronization packet to be transmitted to the slave device;
The abnormality processing unit is
3. The control unit according to claim 2, wherein one of the first packet processing unit and the second packet processing unit is instructed to lower a clock priority of the first synchronization packet or the second synchronization packet. Relay device. The abnormality processing unit is
The relay device according to claim 1, wherein when a failure is detected in the own device, transmission of the second synchronization packet to the slave device is stopped. A first packet processing unit that extracts time information from the first synchronization packet received by the receiving unit;
A second packet processing unit that generates the second synchronization packet to be transmitted to the slave device;
The abnormality processing unit is
The relay apparatus according to claim 4, wherein the second packet processing unit stops the output of the second synchronization packet.   The relay apparatus according to claim 1, wherein a PTP packet is used as the first and second synchronization packets. Receiving a first synchronization packet including time information from the master device;
Based on the first synchronization packet, generate a second synchronization packet including time information indicating a delay time generated in the own device,
Monitor whether there is a failure in the device,
If no failure has occurred, send the second synchronization packet to the slave device;
A control method in a relay apparatus that executes processing for an abnormal time on the second synchronization packet when a failure occurs. A master device,
A slave device;
A communication system comprising a relay device arranged between the master device and the slave device,
The relay device is
A receiver for receiving a first synchronization packet including time information from the master device;
A time information processing unit for generating a second synchronization packet including time information indicating a delay time generated in the device based on the first synchronization packet;
A failure detection unit that monitors whether or not a failure that occurred in the device itself has occurred;
If no failure has occurred, a transmitter that transmits the second synchronization packet to the slave device;
A communication system comprising: an abnormal time processing unit that executes an abnormal time process on the second synchronization packet when a failure occurs.

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