Relay device, relay method, relay program, and time synchronization system

Abstract

Relay devices (10A, 10D) receive time synchronization messages for each of a plurality of time synchronization networks (101A, 101B) using different time synchronization profiles. The relay devices (10A, 10D) select, on the basis of time synchronization messages in the plurality of time synchronization networks (101A, 101B), a master clock to be used in time synchronization from among master clocks (102A, 102B) of each of the plurality of time synchronization networks (101A, 101B).

Description

Technical Field

[0001] The present disclosure relates to a technology for performing time synchronization. Background Art

[0002] In recent years, high-precision time synchronization has been required in various fields. As a technology that serves as a basis for high-precision time synchronization, there is IEEE1588 (see Non-Patent Document 1).

[0003] In IEEE1588, the device that forwards time information has a master and slave structure. The time information is supplied from the grand master, which is the clock source. The time information is forwarded from the device on the master side to the device on the slave side in sequence. A time synchronization profile is set for each device. Each device synchronizes the time with the master clock according to the time information in accordance with the set time synchronization profile.

[0004] In IEEE1588, an Announce message is sent according to each domain number. Then, the best master clock in the parameter comparison of the Announce message is selected as the clock source. At this time, the best master clock is selected as the clock source through the BMCA algorithm. BMCA is the abbreviation of Best Master Clock Algorithm.

[0005] Depending on the field, the IEEE1588 regulations itself cannot be used. Instead, the regulations of the time synchronization profile that is extended according to the IEEE1588 regulations in the field are used. For example, in 5G, there is a Telecom profile (ITUG8275.1 (refer to non-patent document 2)), and for the industry, there is IEEE802.1AS (refer to non-patent document 3). 5G is the abbreviation of 5Generation.

[0006] Patent Document 1 describes a time synchronization process based on a time synchronization profile. In Patent Document 1, a relay device filters only time synchronization packets according to the time synchronization profile and forwards them to a time synchronization unit, performs time synchronization calculations, generates time synchronization packets, and transmits them.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2021-93681

[0010] Non-patent literature

[0011] Non-patent literature 1: IEEE1588-2019 IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems P161, P217, P223

[0012] Non-patent document 2: ITU-T G.8275.1 / Y.1369.1Amendment 2(06 / 2021)Precision timeprotocol telecom profile for phase / time synchronization with full timingsupport from the network Amendment 2P14,P16,P23

[0013] Non-patent document 3: IEEE Std 802.1ASTM-2020Timing and Synchronization for Time-Sensitive Applications P54-57 Summary of the invention

[0014] Problems to be solved by the invention

[0015] The general framework of the time synchronization process is described in non-patent document 1. However, as described in non-patent documents 2 and 3, the time synchronization process is sometimes specified by a separate time synchronization profile depending on the field. Moreover, there is no compatibility between different time synchronization profiles. Therefore, it is necessary to build a time synchronization network according to each time synchronization profile.

[0016] For example, it is assumed that a time synchronization network of time synchronization profile A is laid in a certain area X. It is assumed that a communication method or application that requires a different time synchronization profile B is introduced into area X. The communication method or application that requires a different time synchronization profile B cannot use the time synchronization profile A. Therefore, it is necessary to extend the existing time synchronization network of time synchronization profile B to area X, or to separately set up an expensive master clock corresponding to time synchronization profile B for use in area X.

[0017] In general, the master clock is supplied with time from GPS or the like. Therefore, there are restrictions on the location of the master clock. If a separate master clock is installed for area X, the cost becomes high, and additional monitoring operations are required for area X, which also increases the maintenance cost.

[0018] An object of the present disclosure is to efficiently construct a time synchronization network when there are a plurality of time synchronization networks using different time synchronization profiles.

[0019] Means for solving problems

[0020] The relay device disclosed in the present invention comprises: a receiving unit, which receives time synchronization messages of each of a plurality of time synchronization networks using different time synchronization profiles; and a selecting unit between different profiles, which selects a master clock used in time synchronization from the master clocks of each of the plurality of time synchronization networks based on the time synchronization messages in the plurality of time synchronization networks received by the receiving unit.

[0021] Effects of the Invention

[0022] In the present disclosure, a master clock used in time synchronization is selected from the master clocks of each of a plurality of time synchronization networks. Thus, the master clock can be shared and used in time synchronization networks using different time synchronization profiles. As a result, in the case where there are a plurality of time synchronization networks using different time synchronization profiles, the time synchronization network can be efficiently constructed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram showing the configuration of the time synchronization system 100 according to the first embodiment.

[0024] Figure 2 This is a diagram showing the configuration of the relay device 10 according to the first embodiment.

[0025] Figure 3 This is a flowchart of the processing when a PTP frame is received in implementation mode 1.

[0026] Figure 4 This is a flowchart of the PTP protocol identification process of implementation mode 1.

[0027] Figure 5 This is a diagram illustrating the PTP frame header.

[0028] Figure 6 This figure is an illustration of the main body of the Announce message.

[0029] Figure 7 This is a flowchart of the process of selecting between different profiles in the first embodiment.

[0030] Figure 8 This is an explanatory diagram of items used when the master clock 102 is selected.

[0031] Fig. 9 This is a flowchart of the sending process of implementation mode 1.

[0032] Fig.101 is a diagram showing the structure of a relay device 10 according to Modification 1.

[0033] Fig.11 This is a diagram showing the configuration of a time synchronization system 100 according to the second embodiment.

[0034] Fig.12 This is a flowchart of the processing when a PTP frame is received in implementation mode 2.

[0035] Fig.13 This is a diagram showing the configuration of a time synchronization system 100 according to a third embodiment.

[0036] Fig.14 This is a flowchart of the processing when a PTP frame is received in implementation mode 3. DETAILED DESCRIPTION

[0037] Implementation Method 1

[0038] ***Description of the structure***

[0039] Reference Figure 1 The configuration of the time synchronization system 100 according to the first embodiment will be described.

[0040] The time synchronization system 100 has a plurality of time synchronization networks 101. Each time synchronization network 101 uses a different time synchronization profile. Figure 1 , a time synchronization network 101A and a time synchronization network 101B are shown as the time synchronization network 101. The time synchronization profile A is used in the time synchronization network 101A. The time synchronization profile B is used in the time synchronization network 101B.

[0041] Each time synchronization network 101 includes a master clock 102, one or more relay devices 10, and one or more communication devices 103. Figure 1 In the embodiment, the time synchronization network 101A includes a master clock 102A, relay devices 10A, 10B, 10C, and a communication device 103A. The time synchronization network 101B includes a master clock 102B, relay devices 10D, 10E, 10F, and a communication device 103B.

[0042] In the time synchronization system 100, some relay devices 10 in each time synchronization network 101 are connected to each other. Figure 1 In the example, the relay device 10A in the time synchronization network 101A is connected to the relay device 10D in the time synchronization network 101B.

[0043] In the time synchronization network 101A, the master clock 102A, the relay devices 10A, 10B, 10C, and the communication device 103A mutually transmit and receive PTP frames in accordance with the time synchronization profile A. In addition, the relay device 10A transfers the PTP frame including the information of the time synchronization profile A to the relay device 10D.

[0044] In the time synchronization network 101B, the master clock 102B, the relay devices 10D, 10E, 10F, and the communication device 103A mutually transmit and receive PTP frames in accordance with the time synchronization profile B. In addition, the relay device 10D transfers the PTP frame including the information of the time synchronization profile B to the relay device 10A.

[0045] Here, the PTP frame is a time synchronization message.

[0046] The relay device 10A and the relay device 10D determine which time synchronization profile the PTP frame follows. The relay device 10A and the relay device 10D extract the determination information of the master clock 102 from the PTP frame. The relay device 10A and the relay device 10D compare the determination information between different time synchronization profiles and select the master clock 102 to be used from the respective master clocks 102 of the plurality of time synchronization networks 101. The relay device 10A and the relay device 10D forward the determination information of the selected master clock 102.

[0047] Reference Figure 2 The configuration of the relay device 10 according to the first embodiment will be described.

[0048] The relay device 10 is a computer.

[0049] The relay device 10 includes hardware such as a processor 11, a memory 12, and a plurality of physical ports 13. The processor 11 is connected to other hardware via a signal line and controls the other hardware.

[0050] The processor 11 is an IC that performs processing. IC is the abbreviation of Integrated Circuit. As a specific example, the processor 11 is a CPU. CPU is the abbreviation of Central Processing Unit.

[0051] The memory 12 is a storage device for storing data. As a specific example, the memory 12 is an SRAM or a DRAM. SRAM is an abbreviation of Static Random Access Memory. DRAM is an abbreviation of Dynamic Random Access Memory. The memory 12 implements the functions of the setting management unit 121 and the time management unit 122. The setting management unit 121 manages the time synchronization profile, etc. The time management unit 122 manages the time in the relay device 10.

[0052] The physical port 13 is a port of a wired LAN. LAN is an abbreviation of Local Area Network. The physical port 13 implements the functions of a receiving unit 131 and a transmitting unit 132. The receiving unit 131 receives a PTP frame from the outside. The transmitting unit 132 transmits a PTP frame to the outside.

[0053] As functional structural elements, the relay device 10 includes an L2 / L3 protocol processing unit 21, a PTP protocol identification unit 22, a plurality of time synchronization processing units 23, and a different profile selection unit 24. The functions of each functional structural element of the relay device 10 are implemented by software. The time synchronization profile stored in the setting management unit 121 is set for each functional structural element.

[0054] The memory 12 stores a program for realizing the functions of each functional component of the relay device 10. The program is read and executed by the processor 11. Thus, the functions of each functional component of the relay device 10 are realized.

[0055] The L2 / L3 protocol processing unit 21 is a function of terminating the protocol. The PTP protocol identification unit 22 is a function of identifying the PTP profile. The time synchronization processing unit 23 is a function of performing time synchronization processing. The time synchronization processing unit 23 is set corresponding to each time synchronization profile managed by the setting management unit 121, and performs time synchronization processing according to the corresponding time synchronization profile based on the PTP frame. The time synchronization processing includes processing such as delay calculation, time release and BMCA determination specified by each time synchronization profile as recorded in non-patent documents 1, 2, and 3. The different profile selection unit 24 is a function of selecting a master clock used in time synchronization from the master clocks of each of a plurality of time synchronization networks using different time synchronization profiles.

[0056] exist Figure 2 In FIG. 1 , only one processor 11 is shown. However, there may be multiple processors 11, and the multiple processors 11 may cooperate to execute programs that realize each function.

[0057] ***Description of the action***

[0058] Reference Figure 3 to Figure 9 The operation of the relay device 10 according to the first embodiment will be described.

[0059] The operation procedure of the relay device 10 in the first embodiment corresponds to the relay method in the first embodiment. In addition, the program for realizing the operation of the relay device 10 in the first embodiment corresponds to the relay program in the first embodiment.

[0060] Here, for example Figure 1 The operation of the relay device 10 connected to the other time synchronization network 101, such as the relay devices 10A and 10D in FIG. 10A , 10D, etc., will be described. The other relay devices 10 (relay devices 10B, 10C, 10E, and 10F) operate in the same manner as in the prior art.

[0061] Reference Figure 3 The processing when the PTP frame is received in the first embodiment is described.

[0062] In particular, the processing when receiving an Announce message, which is a type of PTP frame, is described here. In non-patent documents 1, 2, and 3, when receiving an Announce message, a BMCA determination is performed to determine the master clock 102 to be used. The relay device 10 of Embodiment 1 performs a BMCA determination in two stages.

[0063] (Step S11: PTP protocol identification process)

[0064] The PTP frame received by the receiving unit 131 is input to the PTP protocol identification unit 22 via the L2 / L3 protocol processing unit 21 .

[0065] The PTP protocol identification unit 22 identifies which time synchronization profile the input Announce message is for among the plurality of time synchronization profiles. The PTP protocol identification unit 22 inputs the Announce message to the time synchronization processing unit 23 corresponding to the identified time synchronization profile.

[0066] (Step S12: Time synchronization processing)

[0067] The time synchronization processing unit 23 to which the Announce message is input in step S11 performs a BMCA determination according to the corresponding time synchronization profile. For example, if it is a time synchronization processing unit 23 corresponding to the time synchronization profile specified in non-patent document 1, the BMCA determination specified in non-patent document 1 is performed. If it is a time synchronization processing unit 23 corresponding to the time synchronization profile specified in non-patent document 2, the BMCA determination specified in non-patent document 2 is performed. If it is a time synchronization processing unit 23 corresponding to the time synchronization profile specified in non-patent document 3, the BMCA determination specified in non-patent document 3 is performed.

[0068] Through the process of step S12, the master clock 102 to be used is selected in the time synchronization profile. In other words, the best master clock 102 is selected in the time synchronization profile.

[0069] As reference Figure 1 As described above, the relay devices 10A and 10D transmit not only the PTP frames of the time synchronization network 101 to which they belong, but also the PTP frames of the different time synchronization networks 101. Figure 6 In the process of step S11, the receiving unit 131 receives the Announce messages of each of the multiple time synchronization networks using different time synchronization profiles. As a result, through the process of step S12, the master clock 102 to be used is selected according to each time synchronization profile. In other words, the master clock 102 to be used is selected according to each time synchronization network 101 using different time synchronization profiles. If Figure 1 , the master clock 102 used in the time synchronization networks 101A and 101B respectively is selected.

[0070] (Step S13: Selection process between different configuration files)

[0071] The different profile selection unit 24 selects a master clock 102 to be used from the master clocks 102 selected for each time synchronization profile in step S12 based on the Announce messages in the multiple time synchronization networks using different time synchronization profiles. That is, the different profile selection unit 24 selects the best master clock 102 from the master clocks 102 selected respectively according to the multiple time synchronization profiles.

[0072] (Step S14: Sending Process)

[0073] The different profile selection unit 24 sets the transmission setting of the Announce message according to each time synchronization profile based on the master clock 102 selected in step S13. Then, the different profile selection unit 24 notifies the time synchronization processing unit 23 of the Announce message for which the transmission setting is set. The time synchronization processing unit 23 as the notification destination is the time synchronization processing unit 23 corresponding to the time synchronization profile identified in step S11.

[0074] Then, the time synchronization processing unit 23 having received the notification transmits an Announce message via the transmitting unit 132 in accordance with the corresponding time synchronization profile.

[0075] Reference Figure 4 PTP protocol identification processing of implementation mode 1 ( Figure 3 Step S11) is described below.

[0076] Here, the PTP frame header is as shown in non-patent document 1. Figure 5 In addition, the body of the Announce message is as follows in non-patent document 1: Figure 6 That's for sure.

[0077] In step S111 and step S112, the PTP protocol identification unit 22 determines the IPv4 address, IPv6 address, and multicast MAC address. IP is the abbreviation of Internet Protocol. MAC is the abbreviation of Media Access Control.

[0078] Specifically, in step S111, the PTP protocol identification unit 22 determines whether it is an IPv4 address or an IPv6 address based on the value of the Ethertype field of the received frame. If it is an IPv4 address or an IPv6 address, the PTP protocol identification unit 22 causes the process to proceed to step S112. On the other hand, if it is neither an IPv4 address nor an IPv6 address, the PTP protocol identification unit 22 causes the process to proceed to step S113.

[0079] In step S112, the PTP protocol identification unit 22 determines whether it is an IPv4 address or an IPv6 address based on the value of the Ethertype field of the received frame. If it is an IPv4 address, the PTP protocol identification unit 22 causes the process to proceed to step S120. On the other hand, if it is an IPv6 address, the PTP protocol identification unit 22 causes the process to proceed to step S130.

[0080] Here, the Ethertype field has a 2-byte area. For example, in non-patent documents 1 and 3, Ethertype is defined as 88F7, and if it is IPv4, the value is 0800, and if it is IPv6, the value is 86DD.

[0081] The case of multicast MAC addresses is described below.

[0082] In step S113, the PTP protocol identification unit 22 determines whether the MAC address is a specific address.

[0083] Specifically, the PTP protocol identification unit 22 determines whether the MAC address matches the address (01-1B-19-00-00-00 or 01-80-C2-00-00-0E) specified in the non-patent document 1. If it matches, the PTP protocol identification unit 22 causes the process to proceed to step S114. On the other hand, if it does not match, the PTP protocol identification unit 22 ends the process. Figure 3 processing.

[0084] In step S114, the PTP protocol identification unit 22 determines whether the received frame is an Announce message.

[0085] Specifically, the PTP protocol identification unit 22 determines whether it is an Announce message based on the message type (messageType) of the PTP common header. In the case of an Announce message, the message type is 0xB. In the case of an Announce message, the PTP protocol identification unit 22 causes the process to enter step S115. On the other hand, in the case of not an Announce message, the PTP protocol identification unit 22 ends. Figure 3 processing.

[0086] In step S115 , the PTP protocol identification unit 22 confirms the difference in the Announce message header.

[0087] Specifically, the PTP protocol identification unit 22 Figure 5 The Announce message header shown in FIG. 1 is used as a reference. The PTP protocol identification unit 22 determines whether there is a difference between the received Announce message header and the header used as a reference. If there is a difference, the PTP protocol identification unit 22 causes the process to enter step S116. On the other hand, if there is no difference, the PTP protocol identification unit 22 causes the process to enter step S117.

[0088] In step S116, the PTP protocol identification unit 22 extracts the value of the portion that is different from the header used as the reference in the received Announce message header. The PTP protocol identification unit 22 compares the extracted value with the inherent value specified by each time synchronization profile. The PTP protocol identification unit 22 determines the L2 time synchronization profile that specifies the inherent value consistent with the extracted value. L2 is the abbreviation of Layer 2. The PTP protocol identification unit 22 identifies the received Announce message as an Announce message according to the determined L2 time synchronization profile.

[0089] The unique value in the Announce message header is a value that matches the unique conditions defined in the configuration file. As a specific example, the unique value is the version of each configuration file or the value range of the domain number.

[0090] In step S117, the PTP protocol identification unit 22 confirms the difference in the body of the Announce message.

[0091] Specifically, the PTP protocol identification unit 22 Figure 6 The PTP protocol identification unit 22 determines whether there is a difference between the body of the received Announce message and the body used as the reference. If there is a difference, the PTP protocol identification unit 22 causes the process to proceed to step S118. On the other hand, if there is no difference, the PTP protocol identification unit 22 causes the process to proceed to step S119.

[0092] In step S118, the PTP protocol identification unit 22 extracts the value of the part that is different from the body part used as the reference in the body part of the received Announce message. The PTP protocol identification unit 22 compares the extracted value with the inherent value specified by each time synchronization profile. The PTP protocol identification unit 22 determines the L2 time synchronization profile that specifies the inherent value consistent with the extracted value. The PTP protocol identification unit 22 identifies the received Announce message as an Announce message in accordance with the determined L2 time synchronization profile.

[0093] The inherent value in the body of the Announce message is the value of the expanded part of the time synchronization profile. For example, in ITU-T G8275.1 of non-patent document 2, grandmasterPriority1 is not used and is fixed to 128. If the value is consistent, it is judged as ITU-T G8275.1. In addition, in IEEE802.1AS-2020 of non-patent document 3, the value of pathtrace TLV, which becomes an option, is specified. If the value is consistent, it is judged as IEEE802.1AS-2020.

[0094] In step S119, the L2 time synchronization profile associated with the domain number is determined. Here, it is assumed that the domain number is set in advance for each L2 time synchronization profile.

[0095] The processing in the case of IPv4 is described.

[0096] In step S120, the PTP protocol identification unit 22 determines whether the IP address is a specific address.

[0097] Specifically, the PTP protocol identification unit 22 determines whether the IP address matches the address (224.0.1.129 or 224.0.0.107) specified in the non-patent document 1. If it matches, the PTP protocol identification unit 22 causes the process to proceed to step S121. On the other hand, if it does not match, the PTP protocol identification unit 22 ends the process. Figure 3 processing.

[0098] The processing of step S121 to step S126 is the same as the processing of step S113 to step S119. However, instead of determining the L2 time synchronization profile, the IPv4 time synchronization profile is determined.

[0099] The processing in the case of IPv6 is described.

[0100] In step S130, the PTP protocol identification unit 22 determines whether the IP address is a specific address.

[0101] Specifically, the PTP protocol identification unit 22 determines whether the IP address matches the address specified in non-patent document 1 (FF0X:0:0:0:0:0:0:181 or FF02:0:0:0:0:0:0:6B). If it matches, the PTP protocol identification unit 22 causes the process to proceed to step S131. On the other hand, if it does not match, the PTP protocol identification unit 22 ends. Figure 3 processing.

[0102] The processing of step S131 to step S136 is the same as the processing of step S113 to step S119. However, instead of determining the L2 time synchronization profile, the IPv6 time synchronization profile is determined.

[0103] Reference Figure 7 Selection process between different configuration files in implementation mode 1 ( Figure 3 Step S13) is described below.

[0104] In the different profile selection process, the different profile selection unit 24 selects which of the currently selected master clock 102 and the master clock 102 newly selected in step S12 is used as the master clock 102. Here, the time synchronization profile corresponding to the currently selected master clock 102 is set as the time synchronization profile A. The time synchronization profile corresponding to the master clock 102 newly selected in step S12 is set as the time synchronization profile B.

[0105] In non-patent document 1, according to Figure 8 In the process of selecting between different profiles, the different profile selection unit 24 selects the master clock 102 to be used. Figure 8 The items shown are compared in order of priority from high to low, and the master clock 102 to be used is selected.

[0106] However, depending on the time synchronization profile, the reference value or selection method in the BMCA determination may be different. For example, in ITU-TG8275.1 of non-patent document 2, BMCA determination is redefined using 6.3.7 Data set comparison algorithm. Here, grandmasterPriority1 is not used. Similarly, in IEEE802.1AS-2020 of non-patent document 3, BMCA determination is redefined using 10.3.2 systemIdentity.

[0107] Therefore, the different-profile selection unit 24 does not perform comparison on items that are not used for selection of the master clock 102 in at least one of the time synchronization profiles to be compared.

[0108] In step S211, the different profile selection unit 24 determines whether the different profile selection process is necessary. For example, when the setting management unit 121 manages only one time synchronization profile, the different profile selection process is not necessary.

[0109] If the different profile selection process is necessary, the different profile selection unit 24 advances the process to step S212. On the other hand, if the different profile selection process is not necessary, the different profile selection unit 24 ends the process. If the different profile selection process is not necessary, the master clock 102 selected in step S12 is determined as the master clock 102 to be used.

[0110] In step S212, the different profile selection unit 24 determines whether Priority 1 is used in both the time synchronization profiles A and B. If Priority 1 is used in both, the different profile selection unit 24 advances the process to step S213. On the other hand, if Priority 1 is not used in at least one of the profiles, the different profile selection unit 24 advances the process to step S214.

[0111] In step S213, the different profile selection unit 24 compares Priority 1 between the time synchronization profiles A and B. If the time synchronization profile A is preferred, the different profile selection unit 24 selects the currently selected master clock 102 and ends the process. On the other hand, if the time synchronization profile B is preferred, the different profile selection unit 24 selects the newly selected master clock 102 and ends the process. In the same case, the different profile selection unit 24 advances the process to step S214.

[0112] Next, the different profile selection unit 24 also performs a determination and comparison on whether or not other items are used in the order of priority from high to low until the master clock 102 to be used is selected. In steps S214 and S215, a determination and comparison is performed on whether or not Clockclass is used. In steps S216 and S217, a determination and comparison is performed on whether or not ClockAccuracy is used. In steps S218 and S219, a determination and comparison is performed on whether or not OffsetScaledLogVariance is used. In steps S220 and S221, a determination and comparison is performed on whether or not Priority2 is used. In steps S222 and S223, a determination and comparison is performed on whether or not ClockIdentity is used.

[0113] When the master clock 102 to be used is not selected by the last ClockIdentity, the different-profile selection unit 24 performs error processing and ends the processing.

[0114] Reference Fig. 9 The sending process of implementation mode 1 ( Figure 3 Step S14) is described below.

[0115] In the sending process, the different profile selection unit 24 performs the sending setting of the Announce message. At this time, the different profile selection unit 24 sets the value in the Announce message of the master clock 102 selected in step S13 and the inherent value of the Announce message received in step S11. Here, the different profile selection unit 24 sets the inherent value for the item in the time synchronization profile of the Announce message received in step S11 that has the inherent value. On the other hand, the different profile selection unit 24 sets the value in the Announce message of the master clock 102 selected in step S13 for the item that does not have the inherent value.

[0116] Thus, an Announce message is generated according to the time synchronization profile of the Announce message received in step S11 and indicates the time synchronization information of the master clock 102 selected by the different profile selection unit 24 .

[0117] In step S311 , the different profile selection unit 24 reads the time synchronization profile of the Announce message received in step S11 .

[0118] In step S312, the different profile selection unit 24 determines whether there is a unique value in the time synchronization profile of the Announce message received in step S11 for Priority 1. If there is no unique value, the different profile selection unit 24 advances the process to step S313. On the other hand, if there is a unique value, the different profile selection unit 24 advances the process to step S314.

[0119] In step S313, the different profile selection unit 24 sets the value of Priority 1 in the Announce message of the master clock 102 selected in step S13 to Priority 1. On the other hand, in step S314, the different profile selection unit 24 sets the inherent value of Priority 1 in the time synchronization profile of the Announce message received in step S11 to Priority 1.

[0120] Next, the selection unit 24 between different profiles similarly determines whether there are inherent values ​​and sets the item values ​​for other items. In steps S315 to S317, it is determined whether there are inherent values ​​for Clockclass and the item value is set. In steps S318 to S320, it is determined whether there are inherent values ​​for ClockAccuracy and the item value is set. In steps S321 to S323, it is determined whether there are inherent values ​​for OffsetScaledLogVariance and the item value is set. In steps S324 to S326, it is determined whether there are inherent values ​​for Priority2 and the item value is set. In steps S327 to S329, it is determined whether there are inherent values ​​for ClockIdentity and the item value is set. In steps S330 to S332, it is determined whether there are inherent values ​​for the Option area and the item value is set.

[0121] exist Figure 3 In the processing of , the processing when the PTP frame is an Announce message is described. Sometimes the PTP frame is a message other than the Announce message. In this case, the relay device 10 performs the processing as follows.

[0122] The relay device 10 determines whether the message contains the time information of the master clock 102 selected as the master clock 102 to be used. In the case of a message containing the time information of the selected master clock 102, the relay device 10 performs time synchronization processing based on the time information contained in the message through the time synchronization processing unit 23 corresponding to the time synchronization profile of the message. In addition, the time synchronization processing unit 23 transmits the time information contained in the message to the device on the slave side and the relay device 10 of other time synchronization network 101.

[0123] Here, the time synchronization processing unit 23 sends only to the time synchronization network 101 side using the time synchronization profile with a low priority among the relay devices 10 of other time synchronization networks 101. The time synchronization network 101 using the time synchronization profile with a low priority is a time synchronization network other than the time synchronization network to which the selected master clock belongs. Figure 1 In the case where the selected master clock 102 is the master clock 102A, the relay device 10A transmits the time information of the master clock 102A to the communication device 103A and the relay device 10D. When the selected master clock 102 is the master clock 102B, the relay device 10A transmits the time information of the master clock 102B only to the communication device 103A.

[0124] ***Effects of Implementation Method 1***

[0125] As described above, the relay device 10 of Embodiment 1 selects a master clock 102 to be used for time synchronization from the respective master clocks 102 of the plurality of time synchronization networks 101. The relay device 10 of Embodiment 1 converts the time synchronization information related to the selected master clock 102 into an Announce message in the format of another time synchronization profile.

[0126] Thus, the master clock 102 can be shared in the time synchronization network 101 using different time synchronization profiles. As a result, when there are multiple time synchronization networks using different time synchronization profiles, the time synchronization network can be efficiently constructed. For example, the number of expensive master clocks 102 can be reduced.

[0127] ***Other structures***

[0128] <Modification 1>

[0129] In the first embodiment, each functional component is implemented by software. However, as a modification example 1, each functional component may be implemented by hardware. Regarding this modification example 1, the differences from the first embodiment will be described.

[0130] Reference Fig.10 The configuration of the relay device 10 according to Modification 1 will be described.

[0131] When each functional component is realized by hardware, the relay device 10 includes an electronic circuit 14 instead of the processor 11 and the memory 12. The electronic circuit 14 is a dedicated circuit that realizes the functions of each functional component and the memory 12.

[0132] As the electronic circuit 14, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, and an FPGA are envisioned. GA is the abbreviation of Gate Array. ASIC is the abbreviation of Application Specific Integrated Circuit. FPGA is the abbreviation of Field-Programmable Gate Array.

[0133] Each functional component may be realized by one electronic circuit 14 , or may be realized by distributing multiple electronic circuits 14 .

[0134] <Modification 2>

[0135] As a second modification, some of the functional components may be implemented by hardware, and the other functional components may be implemented by software.

[0136] The processor 11, the memory 12, and the electronic circuit 14 are referred to as a processing circuit. That is, the functions of each functional component are realized by the processing circuit.

[0137] Implementation Method 2

[0138] The difference between the second embodiment and the first embodiment is that a priority profile, that is, a priority profile, can be set. In the second embodiment, this difference will be described, and the description of the same points will be omitted.

[0139] When there is an already established time synchronization network 101, a new time synchronization network 101 with a different time synchronization profile may be added. In this case, it is considered to set the time synchronization profile used in the already established time synchronization network 101 as a priority profile. As a result, the master clock 102 of the already established time synchronization network 101 is definitely selected as the master clock 102 to be used.

[0140] As a result, it is not necessary to provide the master clock 102 in the newly added time synchronization network 101. In addition, it is not necessary to lay a network up to the master clock 102 in the newly added time synchronization network 101.

[0141] ***Description of the structure***

[0142] Reference Fig.11 The configuration of the time synchronization system 100 according to the second embodiment will be described.

[0143] exist Fig.11 In the embodiment, the time synchronization system 100 includes a time synchronization network 101C and a time synchronization network 101D. The time synchronization profile C is used in the time synchronization network 101C. The time synchronization profile D is used in the time synchronization network 101D. Fig.11 In FIG. 1 , it is assumed that the time synchronization network 101C has already been laid, and then a new time synchronization network 101D is added.

[0144] The time synchronization network 101C includes master clocks 102C and 102D, relay devices 10G, 10H, and 10I, and a communication device 103C. The time synchronization network 101D includes relay devices 10J, 10K, and 10M, and a communication device 103D. That is, the time synchronization network 101D does not include the master clock 102 .

[0145] The relay device 10G in the time synchronization network 101C is connected to the relay device 10J in the time synchronization network 101D.

[0146] ***Description of the action***

[0147] Reference Fig.12The operation of the relay device 10 according to the second embodiment will be described.

[0148] Here, it is assumed that the different profile selection unit 24 of the relay device 10J is set so that the time synchronization profile C is the priority profile.

[0149] Step S11A, step S12A and step S14A are Figure 3 Step S11, step S12 and step S14 are the same.

[0150] (Step S13A: Selection process between different configuration files)

[0151] and Figure 3 Similarly, in step S13, the different profile selection unit 24 selects the master clock 102 to be used from the master clocks 102 selected in step S12 according to each time synchronization profile based on the Announce messages in the multiple time synchronization networks. That is, the different profile selection unit 24 selects the best master clock 102 from the master clocks 102 selected according to the multiple time synchronization profiles.

[0152] However, when the priority profile is set, the different profile selection unit 24 does not compare the different profiles, but selects the master clock 102 in the time synchronization network 101 using the priority profile as the master clock 102 to be used.

[0153] The relay device 10J sets the time synchronization profile C as the priority profile. Therefore, the different profile selection unit 24 of the relay device 10J selects the master clock 102 in the time synchronization network 101C as the master clock 102 to be used without comparing the different profiles.

[0154] ***Effects of Implementation Method 2***

[0155] As described above, the relay device 10 according to the second embodiment can set a priority profile, that is, a priority profile for time synchronization.

[0156] This makes it possible to intentionally select the master clock 102 of the time synchronization network 101 that uses a specific time synchronization profile. For example, the time synchronization profile used in the already installed time synchronization network 101 is set as the priority profile. This makes the master clock 102 and the network leading to the master clock 102 unnecessary in the newly added time synchronization network 101.

[0157] Implementation 3

[0158] The difference between the third embodiment and the first embodiment is that a time synchronization profile to be compared, that is, a comparison target profile, can be set. In the third embodiment, this difference will be described, and the description of the same points will be omitted.

[0159] Depending on the time synchronization profile, the required time accuracy may be different. A master clock 102 of the time synchronization network 101 using a time synchronization profile with low required time accuracy may be selected. When such a master clock 102 is selected, the required time accuracy may not be met.

[0160] For example, due to a failure of the master clock 102, a situation may occur in which no master clock 102 of the time synchronization network 101 using a time synchronization profile with high required time accuracy is connected. In this case, a master clock 102 of the time synchronization network 101 using a time synchronization profile with low required time accuracy is selected. In general, the master clock 102 is redundant in each time synchronization network 101. However, there is a possibility that all the master clocks 102 in the time synchronization network 101 fail.

[0161] ***Description of the structure***

[0162] Reference Fig.13 The configuration of the time synchronization system 100 according to the third embodiment will be described.

[0163] exist Fig.13 In the embodiment, the time synchronization system 100 includes a time synchronization network 101E and a time synchronization network 101F. The time synchronization profile E is used in the time synchronization network 101E. The time synchronization profile F is used in the time synchronization network 101F. Fig.13 In the example, it is assumed that the time synchronization network 101E requires higher time accuracy than the time synchronization network 101F.

[0164] The time synchronization network 101E includes master clocks 102E and 102F, relay devices 10N, 100, and 10P, and a communication device 103E. The time synchronization network 101F includes master clocks 102G and 102H, relay devices 10Q, 10R, and 10S, and a communication device 103F.

[0165] The relay device 10N in the time synchronization network 101E is connected to the relay device 10Q in the time synchronization network 101F.

[0166] ***Description of the action***

[0167] Reference Fig.14 The operation of the relay device 10 according to the third embodiment will be described.

[0168] Here, it is assumed that the different profile selection unit 24 of the relay device 10N sets only the time synchronization profile E as the comparison target profile. It is assumed that the different profile selection unit 24 of the relay device 10Q sets the time synchronization profiles E and F as the comparison target profiles.

[0169] Step S11B, step S12B and step S14B are Figure 3 Step S11, step S12 and step S14 are the same.

[0170] (Step S13B: Selection process between different configuration files)

[0171] and Figure 3 Similarly, in step S13, the different profile selection unit 24 selects the master clock 102 to be used from the master clocks 102 selected in step S12 according to each time synchronization profile based on the Announce messages in the multiple time synchronization networks. That is, the different profile selection unit 24 selects the best master clock 102 from the master clocks 102 selected according to the multiple time synchronization profiles.

[0172] However, the different profile selection unit 24 selects the master clock 102 to be used from the master clocks 102 of the time synchronization network 101 using the time synchronization profile set as the comparison target profile. Therefore, in the case of the relay device 10N, the master clock 102 of the time synchronization network 101E is selected without performing the comparison between the different profiles. In the case of the relay device 10Q, the master clock 102 is selected after the comparison between the time synchronization networks 101E and 101F.

[0173] like Fig.13 As shown, it is assumed that both the master clocks 102E and 102F of the time synchronization network 101E are disconnected. In this case, the relay device 10N will not select the master clock 102 of the time synchronization network 101F using the time synchronization profile F with low required time accuracy. If the master clock 102 is not selected, the relay device 10N will operate on its own until the selectable master clock 102 is restored.

[0174] ***Effects of Implementation 3***

[0175] As described above, the relay device 10 according to the third embodiment can set a time synchronization profile to be compared, that is, a comparison target profile.

[0176] Thus, the master clock 102 to be used can be selected from the master clocks 102 of the time synchronization network 101 using a specific time synchronization profile. For example, the time synchronization profile used in the time synchronization network 101 whose required time accuracy satisfies the reference is set as the comparison target profile. Thus, the time accuracy required by the time synchronization profile can be satisfied.

[0177] In addition, the word "unit" in the above description may be rewritten as "circuit", "process", "step", "processing" or "processing circuit".

[0178] The above describes the embodiments and variations of the present disclosure. It is also possible to implement several of these embodiments and variations in combination. In addition, it is also possible to partially implement any one or several of the embodiments and variations. In addition, the present disclosure is not limited to the above embodiments and variations, and various changes can be made as needed.

[0179] Description of symbols

[0180] 100: time synchronization system; 101: time synchronization network; 102: master clock; 103: communication device; 10: relay device; 11: processor; 12: memory; 121: setting management unit; 122: time management unit; 13: physical port; 131: receiving unit; 132: sending unit; 21: L2 / L3 protocol processing unit; 22: PTP protocol identification unit; 23: time synchronization processing unit; 24: selection unit between different configuration files.

Claims

1. A relay device, comprising: a receiving unit configured to receive time synchronization messages of respective multiple time synchronization networks using different time synchronization profiles; and A different-profile selection unit selects a master clock used for time synchronization from respective master clocks of the plurality of time synchronization networks based on the time synchronization messages in the plurality of time synchronization networks received by the receiving unit.

2. The relay device according to claim 1, wherein: The relay device further includes a plurality of time synchronization processing units, which are provided corresponding to the respective time synchronization profiles and transmit a time synchronization message indicating the time synchronization information of the master clock selected by the different profile selection unit and in accordance with the corresponding time synchronization profile.

3. The relay device according to claim 2, wherein: A time synchronization processing unit among the plurality of time synchronization processing units corresponding to a time synchronization profile used in a time synchronization network to which the master clock selected by the different profile selection unit belongs performs time synchronization processing based on the time of the master clock selected by the different profile selection unit.

4. The relay device according to claim 2 or 3, wherein: The plurality of time synchronization processing units respectively select a master clock to be used from one or more master clocks in the corresponding time synchronization network, The different-profile selection unit selects a master clock used for time synchronization from among the master clocks selected by the plurality of time synchronization processing units.

5. The relay device according to any one of claims 1 to 4, wherein: The different profile selection unit can set a priority profile as a time synchronization profile with a priority, and when the priority profile is set, selects a master clock in a time synchronization network using the priority profile among the plurality of time synchronization networks as the master clock to be used.

6. The relay device according to claim 5, wherein: When a time synchronization network using a new time synchronization profile is added to an already established time synchronization network, that is, an existing network, the time synchronization profile used in the existing network is set as the priority profile.

7. The relay device according to any one of claims 1 to 6, wherein: The different profile selection unit can set a time synchronization profile as a comparison target, i.e., a comparison target profile. When the comparison target profile is set, a master clock used for time synchronization is selected from the master clocks of each time synchronization network using the comparison target profile among the plurality of time synchronization networks.

8. The relay device according to claim 7, wherein: A time synchronization profile used in a time synchronization network whose time accuracy satisfies a reference is set as the comparison target profile.

9. A relay method, wherein: The computer receives time synchronization messages from multiple time synchronization networks using different time synchronization profiles. The computer selects a master clock used for time synchronization from respective master clocks of the plurality of time synchronization networks based on the time synchronization messages in the plurality of time synchronization networks.

10. A relay program, the relay program causing a computer to function as a relay device, the relay device performing the following processing: Receiving processing, receiving time synchronization messages of respective multiple time synchronization networks using different time synchronization profiles; and The selection process between different profiles selects a master clock used for time synchronization from respective master clocks of the plurality of time synchronization networks according to the time synchronization messages in the plurality of time synchronization networks received by the receiving process.

11. A time synchronization system having a plurality of time synchronization networks using different time synchronization configuration files, wherein: At least any one of the multiple time synchronization networks has a relay device, which receives the time synchronization messages of each of the multiple time synchronization networks, and selects a master clock used in time synchronization from the master clocks of each of the multiple time synchronization networks based on the received time synchronization messages.

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