Conversion device, conversion program, and conversion method

Abstract

To provide a device that enables time synchronization even when different transmission delay measurement methods like End to End and Peer to Peer are used between a master device and a client device synchronized with the time of the master device.SOLUTION: A conversion device 100 includes a Sync message processor 11, a Follow_Up message processor 12, a Delay_Req message processor 13, a Delay_Resp message processor 14, a Pdelay_Req message processor 21, a Pdelay_Resp message processor 22, a Pdelay_Resp_Follow_Up message processor 23, an upper-side transmission delay calculator 40 for calculating a transmission delay time pt1 between the master device 200 and the conversion device 100, an internal processing time calculator 50 for calculating the internal processing time of the conversion device 100, and a CF processor 60 for storing the sum of pt1 and the internal processing time in a Follow_Up message.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a conversion device, a conversion program, and a conversion method that convert the transmission delay measurement method of a host device that performs PTP (Precision Time Protocol) communication to the transmission delay measurement method of a slave device that performs PTP communication when the transmission delay measurement methods are different between the host device and the slave device. [Background Art]

[0002] The Precision Time Protocol (hereinafter referred to as PTP) defined in Non-Patent Document 1 is a protocol that achieves accurate clock synchronization in packet-based network systems.

[0003] In PTP, a format called a profile is specified for each field, and time synchronization cannot be performed between different profiles. Therefore, it is necessary to construct a separate time distribution network for each field, resulting in high costs. Here, one of the reasons why time synchronization cannot be performed between different profiles is the difference in transmission delay measurement methods. For Transparent Clocks, there are two types of transmission delay measurement methods: End to End and Peer to Peer. Since the messages used are different for each method, time synchronization cannot be achieved. [Prior Art Literature] [Non-Patent Literature]

[0004] [Non-Patent Document 1] IEEE Std 1588TM-2019 IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] This disclosure aims to provide a device that enables time synchronization even when two different transmission delay measurement methods, such as end-to-end and peer-to-peer, are used between a higher-level device and a lower-level device that is synchronized with the time of the higher-level device. [Means for solving the problem]

[0006] The conversion device according to this disclosure is a conversion device that converts the transmission delay measurement method of a higher-level device performing PTP (Precision Time Protocol) communication to the transmission delay measurement method of a lower-level device when the transmission delay measurement method differs between the higher-level device and the lower-level device performing PTP communication. The conversion device relating to this disclosure is A Sync message processing unit receives a Sync message transmitted from the above-level device and records the reception time dt1, and records the transmission time dt2 of the Sync message when it is transmitted to the below-level device for relaying purposes. A Follow_Up message processing unit extracts the transmission time T1 of the Sync message from the Follow_Up message, which stores the transmission time T1 of the Sync message from the higher-level device and is transmitted from the higher-level device. A Delay_Req message processing unit that sends a Delay_Req message to the aforementioned higher-level device and records the transmission time T3 of the Delay_Req message, A Delay_Resp message processing unit extracts the reception time T4 of the Delay_Req message from a Delay_Resp message transmitted from the host device, which stores the reception time T4 of the Delay_Req message. A Pdelay_Req message processing unit records the reception time t2 of the Pdelay_Req message transmitted from the lower-level device, A Pdelay_Resp message processing unit stores the reception time t2 of the Pdelay_Req message in a Pdelay_Resp message, and transmits the Pdelay_Resp message containing the reception time t2 of the Pdelay_Req message to the lower-level device. A Pdelay_Resp_Follow_Up message processing unit stores the transmission time t3 of the Pdelay_Resp message in a Pdelay_Resp_Follow_Up message, and transmits the Pdelay_Resp_Follow_Up message containing the transmission time t3 of the Pdelay_Resp message to the lower-level device. A higher-level transmission delay calculation unit calculates a transmission delay time pt1 between the higher-level device and the conversion device using the reception time dt1 of the Sync message, the transmission time T1 of the higher-level device of the Sync message, the transmission time T3 of the Delay_Req message, and the reception time T4 of the Delay_Req message. An internal processing time calculation unit calculates the internal processing time of the conversion device using the reception time dt1 of the Sync message and the transmission time dt2 for relaying the Sync message. A total value storage unit stores the sum of the transmission delay time pt1 between the higher-level device and the conversion device and the internal processing time of the conversion device in the CorrectionField of the Follow_Up message, and transmits the Follow_Up message containing the total value to the lower-level device for relaying purposes. It is equipped with. [Effects of the Invention]

[0007] The conversion device according to this disclosure comprises a Delay_Req message processing unit, a Delay_Resp message processing unit, a higher-level transmission delay calculation unit, and a total value storage unit. Therefore, the conversion device according to this disclosure enables time synchronization even when two different transmission delay measurement methods, such as End to End and Peer to Peer, are used between a higher-level device and a lower-level device synchronized with the time of the higher-level device. [Brief explanation of the drawing]

[0008] [Figure 1] The figure in Embodiment 1 shows the operation of TC101 as Comparative Example 1 of the conversion device 100. [Figure 2] The figure in Embodiment 1 shows the operation of TCl02 as Comparative Example 2 of the conversion device 100. [Figure 3] The diagram in Embodiment 1 illustrates the general operation of the conversion device 100, showing the process of converting End to End to Peer to Peer. [Figure 4] This figure illustrates the detailed operation of the conversion device 100 in Embodiment 1. [Figure 5] A diagram illustrating each time point shown in Figure 4, in the first embodiment. [Figure 6] This figure shows the block configuration of the conversion device 100 in Embodiment 1. [Figure 7] The figure in Embodiment 1 shows the case of one step without a Follow_Up message. [Figure 8] This figure shows the hardware configuration of the conversion device 100 in Embodiment 1. [Figure 9] The diagram of Embodiment 1 shows a configuration in which the functions of the conversion device 100 are realized by hardware. [Modes for carrying out the invention]

[0009] In the descriptions and drawings of the embodiments, the same elements and corresponding elements are denoted by the same reference numerals. The descriptions of elements denoted by the same reference numerals are omitted or simplified as appropriate. In the following embodiments, "part" may be read as "circuit," "process," "procedure," "process," or "circuitry" as appropriate.

[0010] Embodiment 1. Hereinafter, the conversion apparatus 100 according to the first embodiment will be described with reference to the drawings. The conversion apparatus 100 is an apparatus that converts the transmission delay measurement method of a higher-level apparatus to the transmission delay measurement method of a lower-level apparatus when the transmission delay measurement methods differ between the higher-level apparatus performing PTP communication and the lower-level apparatus performing PTP communication. In the first embodiment, it is assumed that the higher-level apparatus is a master apparatus 200 and the lower-level apparatus is a client apparatus 300. In addition, CF described below indicates "CorrectionField" in a PTP message.

[0011] In FIG. 1, as Comparative Example 1 of the conversion apparatus 100, a Transparent Clock 101 will be described. In FIG. 2, as Comparative Example 2 of the conversion apparatus 100, a Transparent Clock 102 will be described. Hereinafter, Transparent Clock is abbreviated as TC.

[0012] FIG. 1 is a diagram explaining the operation of TC 101 according to Comparative Example 1. In FIG. 1, a master apparatus 201 and a client apparatus 301 implement a transmission delay measurement method based on End to End. TC 101 transmits packets based on End to End. In FIG. 1, messages are exchanged as follows.

[0013] <Message exchange in End to End> 2-step mode will be described below. In 1-step mode, the Follow_Up message indicated by the broken arrow is not used. (1) In step S11, the master apparatus 201 transmits a Sync message. (2) In step S12, the master apparatus 201 stores the transmission time T1 of the Sync message into a Follow_Up message and transmits the Follow_Up message. (3) In step S13, TC 101 records the reception time dt1 when the Sync message is received and the transmission time dt2 when the Sync message is transmitted. (4) In step S14, TC101 stores internal processing time = dt2-dt1 as the processing time inside the device of TC101 (hereinafter referred to as internal processing time) into the CF of the Follow_Up message, and transmits the message. (5) In step S15, the client device 301 records the time T2 at which the Sync message is received. (6) In step S16, the client device 301 transmits a Delay_Req message, and at this time, stores the transmission time T3 into the Delay_Req message and transmits the message. (7) In step S17, TC101 records the time dt3 at which the Delay_Req message is received and the time dt4 at which the Delay_Req message is transmitted. (8) In step S18, the master device 201 records the time T4 at which the Delay_Req message is received. (9) In step S19, the master device 201 places T4 in a Delay_Resp message and transmits the message. (10) In step S20, TC101 stores internal processing time of TC101 = dt4-dt3 into the CF of the Delay_Resp message, and transmits the message.

[0014] <Offset Calculation Method between Master Device 201 and Client Device 301> Using "T1, T2, T3, T4, dt2-dt1, dt4-dt3" obtained through the above message exchange, the client device 301 can calculate the following offset. Offset = {(T2-T1-(dt2-dt1))-(T4-T3-(dt4-dt3))} / 2 By correcting the time of the client device based on the offset, the client device can synchronize its time with that of the master device.

[0015] In the case of 1-step, T1 and the internal processing time = dt2-dt1 to be stored in the Follow_Up message are placed in the Sync message and transmitted.

[0016] FIG. 2 is a diagram explaining the operation of TC102 in Comparative Example 2. In FIG. 2, the master device 202 and the client device 302 implement a transmission delay measurement method based on Peer to Peer. TC102 transmits packets based on Peer to Peer. In FIG. 2, messages are exchanged as follows.

[0017] <Message exchange in Peer to Peer> The 2-step process is described below. In 1-step, the Follow_Up message indicated by the dashed arrow and the Pdelay_Resp_Follow_Up message indicated by two dashed arrows are not used. (1) In step S31, TC102 transmits a Pdelay_Req message to the master device 202, and records the transmission time t1. (2) In step S32, the master device 202 records the time t2 at which the Pdelay_Req message is received. (3) In step S33, the master device 202 transmits a Pdelay_Resp message, records the transmission time t3, and stores the reception time t2 of the Pdelay_Req message in the Pdelay_Resp message for transmission at this time. (4) In step S34, the master device 202 stores the time t3 in a Pdelay_Resp_Follow_Up message and transmits the same. (5) In step S35, TC102 records the time t4 at which the Pdelay_Resp message is received. (6) In step S36, TC102 uses each of the times (t1, t2, t3, t4) to calculate the transmission delay time pt1 between the master device 20 and TC102 with the following formula. Transmission delay time pt1={(t2-t1)+(t4-t3)} / 2 (7) In step S37, similarly, the client device 302 calculates the transmission delay time pt2 between TC102 and the client device 302. The same exchange as in steps S31 to S35 takes place between TC102 and the client device 302. The times t1 to t4 in steps S31 to S35 correspond to the times 5 to t8 shown in Figure 2. Transmission delay time pt2 = {(t6-t5)+(t8-t7)} / 2 (8) In step S38, the master device 202 sends a Sync message. (9) In step S39, the master device 202 sends the transmission time T1 of the Sync message along with the Follow_Up message. (10) In step S40, TC102 records the time dt1 when it received the Sync message and the time dt2 when it sent it. (11) In step S41, TC102 stores in the CF of the Follow_Up message the sum of the transmission delay time pt1 between the master device 202 and TC102 and the internal processing time of TC102 (dt2-dt1), pt1+(dt2-dt1), and transmits it. (12) The client device 302 uses the transmission delay time pt2 calculated in step S37 and the total value pt1+(dt2-dt1) stored in the CF of the Follow_Up message to calculate the time T2 of the client device that should be synchronized with the transmission time T1 of the Sync message using the following formula. Client device time T2 = T1 + pt1 + (dt2 - dt1) + pt2 The time T2 calculated using the above formula is the time when it synchronizes with the master device 202.

[0018] For a single step, send it as follows: The time T1 and total value (pt1 + (dt2 - dt1)) that were stored and sent in the Follow_Up message are included in the Sync message and sent. In this case, the total value is stored in the CF of the Sync message. Additionally, the timestamps t3 and t7, which were previously transmitted in the Pdelay_Resp_Follow_Up message, are now stored in the CF of the Pdelay_Resp message and transmitted.

[0019] Figure 3 is a diagram illustrating the operation overview of the conversion device 100 of Embodiment 1. In Figures 1 and 2, TC101 (Comparative Example 1) which performs End to End and TC102 (Comparative Example 1) which performs Peer to Peer are described as comparative examples of the conversion device 100. When the master device uses a transmission delay measurement method corresponding to End to End and the client device uses a transmission delay measurement method corresponding to Peer to Peer, TC101 and TC102 cannot synchronize the time between the master device and the client device.

[0020] In contrast, the converter 100 enables time synchronization between the master device and the client device even when the master device uses an end-to-end transmission delay measurement method and the client device uses a peer-to-peer transmission delay measurement method. In Figure 3, the converter 100 is used to convert the transmission delay measurement method from end-to-end to peer-to-peer. This allows the client device 300 to synchronize with the time of the master device 200 even in sections with different transmission delay measurement methods.

[0021] With the converter 100, no modifications or settings are required for the master device 200 and client device 300; the converter 100 alone performs message conversion and value rewriting. Specifically, the master device 200 can use the master device 201 (Figure 1), which uses an end-to-end transmission delay measurement method, as is. Similarly, the client device 300 can use the client device 302 (Figure 2), which uses a peer-to-peer transmission delay measurement method, as is. The master device 200 exchanges messages as usual (end-to-end). The client device 300 exchanges messages as usual (peer-to-peer). Because there are no restrictions on the master device 200 and client device 300, the converter 100 can be installed between any PTP devices. The time taken for the conversion process by the conversion device 100 is added to the normal internal processing time to perform time synchronization. Therefore, there is no degradation in time accuracy due to the conversion process.

[0022] Figure 4 is a diagram illustrating the detailed operation of the conversion device 100 of Embodiment 1. Figure 5 is a table explaining each time point shown in Figure 4. Figure 6 shows the block configuration of the conversion device 100.

[0023] ***Explanation of the structure*** The configuration of the conversion device 100 will be explained with reference to Figure 6. The conversion device 100 includes a Sync message processing unit 11, a Follow_Up message processing unit 12, a Delay_Req message processing unit 13, a Delay_Resp message processing unit 14, a Pdelay_Req message processing unit 21, a Pdelay_Resp message processing unit 22, a Pdelay_Resp_Follow_Up message processing unit 23, a master-side packet communication unit 30M, a client-side packet communication unit 30C, a higher-level transmission delay calculation unit 40, an internal processing time calculation unit 50, and a CF processing unit 60.

[0024] The Sync message processing unit 11 is a first processing means. The Follow_Up message processing unit 12 is a second processing means. The Delay_Req message processing unit 13 is a third processing means. The Delay_Resp message processing unit 14 is a fourth processing means. The Pdelay_Req message processing unit 21 is a fifth processing means. The Pdelay_Resp message processing unit 22 is a sixth processing means. The Pdelay_Resp_Follow_Up message processing unit 23 is a seventh processing means. The master device 200 is an upper-level device. The client device 300 is a lower-level device. The CF processing unit 60 is a total value storage unit.

[0025] In the following description, each message processing unit is expressed as Sync processing unit 11, for example.

[0026] The functions of each component are as follows. (1)<Master-side packet communication unit 30M, Client-side packet communication unit 30C> The master-side packet communication unit 30M and the client-side packet communication unit 30C transmit and receive PTP packets to and from the master device 200 and the client device 300, respectively. (2)<Sync processing unit 11> The Sync processing unit 11 receives a Sync message from the master device 200, records the reception time dt1 and the transmission time dt2 of the Sync message to the client device 300, and performs the following processes. (a) transmits the reception time dt1 to the upper-side transmission delay calculation unit 40, (b) transmits the reception time dt1 and the transmission time dt2 to the internal processing time calculation unit 50, (c) transmits the Sync message to the CF processing unit 60. (3)<Follow_Up processing unit 12> receives a Follow_Up message (which stores the Follow_Up message transmission time T1) from the master device 200, transmits the Follow_Up message to the CF processing unit 60, and extracts the transmission time T1 and transmits the transmission time T1 to the upper-side transmission delay calculation unit 40. (4)<Delay_Req processing unit 13> The Delay_Req processing unit 13 performs the following steps. (a) Transmit a Delay_Req message to the master device 200, (b) Record the transmission time T3 of the Delay_Req message, (c) Transmit the transmission time T3 to the upper transmission delay calculation unit 40. (5)<Delay_Resp processing unit 14> The Delay_Resp processing unit 14 performs the following steps. (a) Receive a Delay_Resp message (which stores the reception time T4 of the Delay_Req message) from the master device 200, (b) Extract the reception time T4 from the Delay_Resp message and transmit it to the upper transmission delay calculation unit 40. (6)<Pdelay_Req processing unit 21> The Pdelay_Req processing unit 21 performs the following steps. (a) Receive a Pdelay_Req message from the client device 300, (b) Record the reception time t2 of the Pdelay_Req message, (c) Transmit the reception time t2 to the Pdelay_Resp processing unit 22. (7)<Pdelay_Resp processing unit 22> The Pdelay_Resp processing unit 22 performs the following steps. (a) Store the reception time t2 of the Pdelay_Req into a Pdelay_Resp message and transmit the message to the client device 300, (b) Record the transmission time t3 of the Pdelay_Resp message and transmit the time to the Pdelay_Resp_Follow_Up processing unit. (8)<Pdelay_Resp_Follow_Up processing unit 23> The Pdelay_Resp_Follow_Up processing unit 23 performs the following steps. (a) Store the transmission time t3 received from the Pdelay_Resp processing unit 22 into a Pdelay_Resp_Follow_Up message and transmit the message to the client device 300. (9)<Upper transmission delay calculation unit 40> The upper transmission delay calculation unit 40 performs the following processes. (a) Calculate the transmission delay time pt1 between the master device 200, which is an upper-level device, and the conversion device 100. Although details will be described later, if the calculation formula is denoted by f, the transmission delay time pt1 is pt1=f(dt1,T1,T3,T4) calculated by the above formula. (b) Transmit the transmission delay time pt1 to the CF processing unit 60. (10)<Internal Processing Time Calculation Unit 50> The internal processing time calculation unit 50 performs the following processes. (a) Calculate the internal processing time (dt2-dt1) of the conversion device 100 using the reception time dt1 and the transmission time dt2 received from the Sync processing unit 11, (b) Transmit the internal processing time (dt2-dt1) to the CF processing unit 60. (11)<CF Processing Unit 60> The CF processing unit 60 stores values in the CF of each message.

[0027] ***Description of Operation*** The operation of the conversion device 100 will be described with reference to FIG. 4. The operation of the conversion device 100 corresponds to a conversion method. The operation of the conversion device 100 also corresponds to the processing performed by the conversion program 131.

[0028] <Flow of Message Exchange> 2-step processing is described in FIG. 4. In 1-step processing, the Follow_Up message and Pdelay_Resp_Follow_Up message indicated by broken line arrows are not used. 1-step processing will be described later with reference to FIG. 7.

[0029] End-to-end communication is performed between the master device 200 and the conversion device 100. For the entire network, that is, between the master device 200 and the client device 300, the time of the client device 300 is synchronized with the time of the master device 200 using a peer-to-peer method.

[0030] <Step S101, Step S102> In step S101, the master device 200 sends a Sync message. In step S102, the master device 200 stores the transmission time T1 of the Sync message in the Follow_Up message and sends it. The following processes A and B are performed in parallel by the converter 100.

[0031] <Process A> Process A is described below. Process A consists of steps S103A and S104A.

[0032] <Step S103A> The master-side packet communication unit 30M receives the Sync message. In step S103A, the Sync processing unit 11 records the time dt1 when the Sync message was received and transmits the Sync message to the client device 300 via the client-side packet communication unit 30C. The Sync processing unit 11 records the time dt2 when the Sync message was transmitted to the client device 300.

[0033] <Step S104A> The master packet communication unit 30M receives the Follow_Up message. The Follow_Up processing unit 12 sends the received Follow_Up message to the CF processing unit 60. The CF processing unit 60 stores in the CF of the Follow_Up message the sum of the transmission delay time pt1 between the master device 200 and the converter 100 and the internal processing time (dt2-dt1), namely pt1+(dt2-dt1). In step S104A, the CF processing unit 60 sends a Follow_Up message containing the above total value to the client device 300 via the client-side packet communication unit 30C.

[0034] Normally, the CF value of an End-to-End Follow_Up message is "dt2-dt1". Here, if we consider the entire message exchange between the master device 200 and the converter 100 on the left side of Figure 4 as one set, the transmission delay time pt1 is the value obtained in the previous set.

[0035] <Process B> Process B is described below. Process B consists of steps S105B to S109B.

[0036] <Step S105B> In step S105B, the Delay_Req processing unit 13 sends a Delay_Req message to the master device 200 via the master-side packet communication unit 30M. At this time, the Delay_Req processing unit 13 stores the transmission time T3 of the Delay_Req message in the Delay_Req message. Normally, the TC does not send a Delay_Req message, but only performs forwarding.

[0037] <Steps S106B to S108B> In step S106B, the master device 200 records the reception time T4 of the Delay_Req message. In step S107B, the master device 200 stores the reception time T4 in the Delay_Resp message and sends it. In step S108B, the Delay_Resp processing unit 14 receives a Delay_Resp message via the master-side packet communication unit 30M and terminates. Normally, the TC does not terminate the Delay_Resp message but only performs forwarding. The Delay_Resp processing unit 14 transmits the reception time T4 to the upper-level transmission delay calculation unit 40.

[0038] <Step S109B> In step S109B, the upper-level transmission delay calculation unit 40 calculates the transmission delay time pt1 between the master device 200 and the converter 100. The upper-level transmission delay calculation unit 40 calculates the transmission delay time pt1 using Equation 1. pt1={(dt1−T1)+(T4−T3)} / 2 (Formula 1)

[0039] The above is process B.

[0040] (1) In step S110, the client device 300 sends a Pdelay_Req message to the conversion device 100 and records the transmission time t1. (2) In step S111, the Pdelay_Req processing unit 21 records the reception time t2 of the Pdelay_Req message. (3) In step S112, the Pdelay_Resp processing unit 22 sends a Pdelay_Resp message, records the transmission time t3, and stores the reception time t2 in the Pdelay_Resp message and sends it. (4) In step S113, the Pdelay_Resp_Follow_Up processing unit 23 stores the transmission time t3 in the Pdelay_Resp_Follow_Up message and transmits it. (5) In step S114, the client device 300 records the time t4 when the Pdelay_Resp message was received. (6) In step S115, the client device 300 uses the transmission time t1, reception time t2, transmission time t3, and reception time t4 to calculate the transmission delay time pt2 between the converter 100 and the client device 300 using Equation 2. Transmission delay time pt2 = {(t2-t1)+(t4-t3)} / 2 (Equation 2) The client device 300 performs time synchronization according to Equation 3. Time T2 is the time the Sync message was received by the client device 300. T2=T1+pt1+(dt2-dt1)+pt2 (Formula 3)

[0041] Figure 7 shows the case with one step. Although Figure 4 showed two steps, the one-step case is as follows, as shown in Figure 7. (1) Store the transmission time T1, which will be stored and sent in the Follow_Up message, in the Sync message. (2) The (dt2-dt1) stored in the CF of the Follow_Up message is placed in the CF of the Sync message and sent as CF=pt1+(dt2-dt1). (3) The transmission time t3 stored in the Pdelay_Resp_Follow_Up message is placed on the CF of the Pdelay_Resp message and sent.

[0042] <Hardware configuration of the conversion device 100> Figure 8 shows the hardware configuration of the converter 100. The hardware configuration of the converter 100 will be explained with reference to Figure 8.

[0043] The converter 100 is a computer. The converter 100 includes a processor 110. In addition to the processor 110, the converter 100 includes several other hardware components. These hardware components include a main memory 120, an auxiliary memory 130, an input interface 140, an output interface 150, and a communication interface 160. The processor 110 is connected to and controls the other hardware components via signal lines 170.

[0044] The conversion device 100 includes, as functional elements, a Sync processing unit 11, a Follow_Up processing unit 12, a Delay_Req processing unit 13, a Delay_Resp processing unit 14, a Pdelay_Req processing unit 21, a Pdelay_Resp processing unit 22, a Pdelay_Resp_Follow_Up processing unit 23, a master-side packet communication unit 30M, a client-side packet communication unit 30C, a higher-level transmission delay calculation unit 40, an internal processing time calculation unit 50, and a CF processing unit 60. The functions of the Sync processing unit 11, Follow_Up processing unit 12, Delay_Req processing unit 13, Delay_Resp processing unit 14, Pdelay_Req processing unit 21, Pdelay_Resp processing unit 22, Pdelay_Resp_Follow_Up processing unit 23, master-side packet communication unit 30M, client-side packet communication unit 30C, upper-level transmission delay calculation unit 40, internal processing time calculation unit 50, and CF processing unit 60 are realized by the conversion program 131.

[0045] The processor 110 is a device that executes the conversion program 131. By executing the conversion program 131, the processor 110 enables the functions of the Sync processing unit 11, Follow_Up processing unit 12, Delay_Req processing unit 13, Delay_Resp processing unit 14, Pdelay_Req processing unit 21, Pdelay_Resp processing unit 22, Pdelay_Resp_Follow_Up processing unit 23, master-side packet communication unit 30M, client-side packet communication unit 30C, upper-level transmission delay calculation unit 40, internal processing time calculation unit 50, and CF processing unit 60. The processor 110 is an IC (Integrated Circuit) that performs arithmetic processing. Specific examples of the processor 110 include a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and a GPU (Graphics Processing Unit).

[0046] Specific examples of the main memory 120 are SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory). The main memory 120 holds the calculation results of the processor 110.

[0047] The auxiliary storage device 130 is a storage device that stores data non-volatilely. A specific example of the auxiliary storage device 130 is an HDD (Hard Disk Drive). Alternatively, the auxiliary storage device 130 may be a portable recording medium. Examples of portable recording media include SD (Secure Digital) memory cards, NAND flash memory, flexible disks, optical disks, compact disks, Blu-ray (registered trademark) disks, and DVDs (Digital Versatile Disks). The auxiliary storage device 130 stores the conversion program 131.

[0048] The input interface 140 is a port to which data is input from each device. The output interface 150 is to which various devices are connected. The output interface 150 is a port to which data is output by the processor 110 to various devices. The communication interface 160 is a communication port for the processor to communicate with the master device 200 and the client device 300.

[0049] The processor 110 loads the conversion program 131 from the auxiliary storage device 130 into the main memory device 120. The processor 110 reads the loaded conversion program 131 from the main memory device 120 and executes it. In addition to the conversion program 131, the main memory device 120 also stores the OS (Operating System). The processor 110 executes the conversion program 131 while executing the OS. The conversion device 100 may have multiple processors that can replace the processor 110. These multiple processors share the task of executing the conversion program 131. Each processor is a device that executes the conversion program 131 in the same way as the processor 110. Data, information, signal values, and variable values ​​used, processed, or output by the conversion program 131 are stored in the main memory device 120, the auxiliary storage device 130, or in registers or cache memory within the processor 110.

[0050] The conversion program 131 is a program that causes a computer to execute each process, each procedure, or each process, by replacing the "part" in the Sync processing unit 11, Follow_Up processing unit 12, Delay_Req processing unit 13, Delay_Resp processing unit 14, Pdelay_Req processing unit 21, Pdelay_Resp processing unit 22, Pdelay_Resp_Follow_Up processing unit 23, master-side packet communication unit 30M, client-side packet communication unit 30C, upper-level transmission delay calculation unit 40, internal processing time calculation unit 50, and CF processing unit 60 with "process," "procedure," or "stage."

[0051] Furthermore, the conversion method is performed by a computer-based conversion device 100 executing a conversion program 131. The conversion program 131 may be provided stored on a computer-readable recording medium, or it may be provided as a program product.

[0052] <Supplementary information on hardware configuration> In Figure 8, the functions of the converter 100 are implemented in software. However, the functions of the converter 100 may also be implemented in hardware. Figure 9 shows a configuration in which the functions of the converter 100 are implemented in hardware. The electronic circuit 500 in Figure 9 is a dedicated electronic circuit that implements the functions of the converter 100, specifically the Sync processing unit 11, Follow_Up processing unit 12, Delay_Req processing unit 13, Delay_Resp processing unit 14, Pdelay_Req processing unit 21, Pdelay_Resp processing unit 22, Pdelay_Resp_Follow_Up processing unit 23, master-side packet communication unit 30M, client-side packet communication unit 30C, upper-level transmission delay calculation unit 40, internal processing time calculation unit 50, and CF processing unit 60. The electronic circuit 500 is connected to the signal line 501. Specifically, the electronic circuit 500 can be a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, or an FPGA. GA is an abbreviation for Gate Array. ASIC is an abbreviation for Application Spec Interface IC Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array. The functions of the components of the converter 100 may be realized by a single electronic circuit or by being distributed across multiple electronic circuits. Alternatively, some functions of the components of the converter 100 may be realized by electronic circuits, and the remaining functions may be realized by software.

[0053] Each of the processor 110 and the electronic circuit 500 is also called a processing circuit or circuit. In the conversion device 100, the functions of the Sync processing unit 11, Follow_Up processing unit 12, Delay_Req processing unit 13, Delay_Resp processing unit 14, Pdelay_Req processing unit 21, Pdelay_Resp processing unit 22, Pdelay_Resp_Follow_Up processing unit 23, master-side packet communication unit 30M, client-side packet communication unit 30C, upper-level transmission delay calculation unit 40, internal processing time calculation unit 50, and CF processing unit 60 may be implemented by circuits.

[0054] ***Explanation of the effects of Embodiment 1*** One reason why time synchronization was not possible between different profiles was the difference in transmission delay measurement methods (End to End, Peer to Peer). However, by using the conversion device 100 of Embodiment 1, even if the transmission delay measurement method differs between the master device 200 and the client device 300, the client device 300 can synchronize its time with the master device 200. As a result, by using the conversion device 100, it is possible to connect profiles with different transmission delay measurement methods, eliminating the need to construct separate time distribution networks and thus reducing equipment costs.

[0055] Embodiment 1 of this disclosure has been described above. Several of Embodiment 1 may be implemented in combination. Alternatively, one or several of them may be implemented in part. This disclosure is not limited to Embodiment 1 described above, and various modifications are possible as needed. [Explanation of Symbols]

[0056] 11 Sync processing unit, 12 Follow_Up processing unit, 13 Delay_Req processing unit, 14 Delay_Resp processing unit, 21 Pdelay_Req processing unit, 22 Pdelay_Resp processing unit, 23 Pdelay_Resp_Follow_Up processing unit, 30M Master-side packet communication unit, 30C Client-side packet communication unit, 40 Upper-side transmission delay calculation unit, 50 Internal processing time calculation unit, 60 CF processing unit, 100 Converter, 101,102 TC, 110 Processor, 120 Main memory, 130 Auxiliary memory, 131 Conversion program, 140 Input interface, 150 Output interface, 160 Communication interface, 170 Signal line, 200,201,202 Master device, 300 Client device.

Claims

1. A conversion device that converts the transmission delay measurement method of a higher-level device to the transmission delay measurement method of a lower-level device when the transmission delay measurement method differs between a higher-level device performing PTP (Precision Time Protocol) communication and a lower-level device performing said PTP communication, A Sync message processing unit receives a Sync message transmitted from the above-level device and records the reception time dt1, and records the transmission time dt2 of the Sync message when transmitting the Sync message to the below-level device for relaying purposes. A Follow_Up message processing unit extracts the transmission time T1 of the Sync message from the Follow_Up message, which stores the transmission time T1 of the Sync message from the host device and is transmitted from the host device. A Delay_Req message processing unit transmits a Delay_Req message to the aforementioned higher-level device and records the transmission time T3 of the Delay_Req message. A Delay_Rep message processing unit stores the reception time T4 of the Delay_Rep message and extracts the reception time T4 of the Delay_Rep message from the Delay_Rep message transmitted from the host device, A Pdelay_Req message processing unit records the reception time t2 of the Pdelay_Req message transmitted from the lower-level device, A Pdelay_Resp message processing unit stores the reception time t2 of the Pdelay_Req message in a Pdelay_Resp message, and transmits the Pdelay_Resp message containing the reception time t2 of the Pdelay_Req message to the lower-level device. A Pdelay_Resp_Follow_Up message processing unit stores the transmission time t3 of the Pdelay_Resp message in a Pdelay_Resp_Follow_Up message, and transmits the Pdelay_Resp_Follow_Up message containing the transmission time t3 of the Pdelay_Resp message to the lower-level device. A higher-level transmission delay calculation unit calculates a transmission delay time pt1 between the higher-level device and the conversion device using the reception time dt1 of the Sync message, the transmission time T1 of the Sync message by the higher-level device, the transmission time T3 of the Delay_Req message, and the reception time T4 of the Delay_Req message. An internal processing time calculation unit calculates the internal processing time of the conversion device using the reception time dt1 of the Sync message and the transmission time dt2 for relaying the Sync message. A total value storage unit stores the sum of the transmission delay time pt1 between the higher-level device and the conversion device and the internal processing time of the conversion device in the CorrectionField of the Follow_Up message, and transmits the Follow_Up message containing the stored total value to the lower-level device for relaying purposes. A conversion device equipped with the following features.

2. When the transmission delay measurement method differs between a higher-level device performing PTP (Precision Time Protocol) communication and a lower-level device performing the same PTP communication, a conversion device, which is a computer that converts the transmission delay measurement method of the higher-level device to the transmission delay measurement method of the lower-level device, Sync message processing includes receiving a Sync message transmitted from the above-level device and recording the reception time dt1, and recording the transmission time dt2 of the Sync message when transmitting the Sync message to the below-level device for relaying purposes, Follow_Up message processing extracts the transmission time T1 of the Sync message from the Follow_Up message, which stores the transmission time T1 of the Sync message from the host device and is transmitted from the host device. Delay_Req message processing, which involves sending a Delay_Req message to the aforementioned higher-level device and recording the transmission time T3 of the Delay_Req message, The Delay_Rep message processing involves extracting the reception time T4 of the Delay_Req message from the Delay_Rep message transmitted from the host device, where the reception time T4 of the Delay_Req message is stored. Pdelay_Req message processing records the reception time t2 of the Pdelay_Req message transmitted from the lower-level device, The Pdelay_Resp message processing involves storing the reception time t2 of the Pdelay_Req message in a Pdelay_Resp message, and sending the Pdelay_Resp message containing the reception time t2 of the Pdelay_Req message to the lower-level device. The Pdelay_Resp_Follow_Up message processing involves storing the transmission time t3 of the Pdelay_Resp message in a Pdelay_Resp_Follow_Up message, and sending the Pdelay_Resp_Follow_Up message containing the transmission time t3 of the Pdelay_Resp message to the lower-level device. A higher-level transmission delay calculation process calculates a transmission delay time pt1 between the higher-level device and the converter, using the reception time dt1 of the Sync message, the transmission time T1 of the Sync message by the higher-level device, the transmission time T3 of the Delay_Req message, and the reception time T4 of the Delay_Req message. An internal processing time calculation process that calculates the internal processing time of the converter using the reception time dt1 of the Sync message and the transmission time dt2 for relaying the Sync message, The CorrectionField of the Follow_Up message stores the sum of the transmission delay time pt1 between the higher-level device and the conversion device and the internal processing time of the conversion device, and the Follow_Up message containing the stored sum is transmitted to the lower-level device for relaying purposes. A conversion program that executes the process.

3. When the transmission delay measurement method differs between a higher-level device performing PTP (Precision Time Protocol) communication and a lower-level device performing the same PTP communication, a conversion device, which is a computer that converts the transmission delay measurement method of the higher-level device to the transmission delay measurement method of the lower-level device, A Sync message processing step includes receiving a Sync message transmitted from the above-level device and recording the reception time dt1, and recording the transmission time dt2 of the Sync message when transmitting the Sync message to the below-level device for relay purposes, A Follow_Up message processing step extracts the transmission time T1 of the Sync message from the Follow_Up message, which stores the transmission time T1 of the Sync message from the host device and is transmitted from the host device. A Delay_Req message processing step that transmits a Delay_Req message to the aforementioned higher-level device and records the transmission time T3 of the Delay_Req message, A Delay_Rep message processing step which extracts the reception time T4 of the Delay_Req message from the Delay_Rep message transmitted from the host device, which stores the reception time T4 of the Delay_Req message. A Pdelay_Req message processing step that records the reception time t2 of the Pdelay_Req message transmitted from the lower-level device, A Pdelay_Resp message processing step includes storing the reception time t2 of the Pdelay_Req message in a Pdelay_Resp message, and transmitting the Pdelay_Resp message containing the reception time t2 of the Pdelay_Req message to the lower-level device. A Pdelay_Resp_Follow_Up message processing step includes storing the transmission time t3 of the Pdelay_Resp message in a Pdelay_Resp_Follow_Up message, and sending the Pdelay_Resp_Follow_Up message containing the transmission time t3 of the Pdelay_Resp message to the lower-level device, A higher-level transmission delay calculation step calculates a transmission delay time pt1 between the higher-level device and the conversion device using the reception time dt1 of the Sync message, the transmission time T1 of the Sync message by the higher-level device, the transmission time T3 of the Delay_Req message, and the reception time T4 of the Delay_Req message. An internal processing time calculation step, which calculates the internal processing time of the conversion device using the reception time dt1 of the Sync message and the transmission time dt2 for relaying the Sync message, A total value storage step involves storing the sum of the transmission delay time pt1 between the higher-level device and the conversion device and the internal processing time of the conversion device in the CorrectionField of the Follow_Up message, and transmitting the Follow_Up message containing the stored total value to the lower-level device for relay purposes. A conversion method to perform this operation.

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