Conversion device, conversion program, and conversion method

Abstract

A conversion device (100) is provided with a Sync message processing unit (11), a FollowUp message processing unit (12), a DelayReq message processing unit (13), a DelayResp message processing unit (14), a PdayReq message processing unit (21), a PdayResp message processing unit (22), a PdayResFollowUp message processing unit (23), and an upper-side transmission delay calculation unit (40) that calculates a transmission delay time (pt1) between a master device (200) and the conversion device (100). An internal processing time calculation unit (50) that calculates the internal processing time of the conversion device (100); and a CF processing unit (60) that stores the sum of the (pt1) and the internal processing time in a FollowUp message.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a conversion apparatus, a conversion program, and a conversion method, which convert a transmission delay measurement method of an upper apparatus into a transmission delay measurement method of a lower apparatus in a case where the transmission delay measurement methods are different between the upper apparatus that performs PTP (Precision Time Protocol) communication and the lower apparatus that performs PTP communication. BACKGROUND

[0002] PTP (Precision Time Protocol) defined in Non-Patent Literature 1 is a protocol that achieves accurate synchronization of clocks in a packet-based network system.

[0003] In PTP, a format called a profile is defined for each domain, and time synchronization cannot be performed between different profiles. Therefore, a time distribution network needs to be constructed separately for each domain, and the cost becomes high. Here, as one of the reasons why time synchronization cannot be performed between different profiles, there is a difference in the transmission delay measurement method. In a Transparent Clock, there are two transmission delay measurement methods, End to End and Peer to Peer, and since the messages used are different, time synchronization cannot be performed.

[0004] PRIOR ART DOCUMENTS

[0005] NON-PATENT LITERATURE

[0006] Non-Patent Literature 1: IEEE Std 1588TM-2019 IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] An object of the present disclosure is to provide an apparatus that can perform time synchronization even in a case where two different transmission delay measurement methods such as End to End and Peer to Peer are used between an upper apparatus and a lower apparatus that performs time synchronization with the upper apparatus.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] The conversion device of the present disclosure is a conversion device that converts a transmission delay measurement method of an upper device that performs PTP (Precision Time Protocol) communication to a transmission delay measurement method of a lower device that performs the PTP communication, in a case where the transmission delay measurement methods are different between the upper device and the lower device.

[0011] The conversion device of the present disclosure has:

[0012] a Sync message processing section that receives a Sync message transmitted from the upper device and records a reception time point dt1, and records a transmission time point dt2 of the Sync message at the time of transmission of the Sync message to the lower device for relaying;

[0013] a Follow_Up message processing section that extracts the transmission time point T1 of the Sync message from the upper device from a Follow_Up message transmitted from the upper device and from the transmission time point T1 of the Sync message of the upper device;

[0014] a Delay_Req message processing section that transmits a Delay_Req message to the upper device, and records a transmission time point T3 of the Delay_Req message;

[0015] a Delay_Resp message processing section that extracts the reception time point T4 of the Delay_Req message from a Delay_Resp message transmitted from the upper device and from the reception time point T4 of the Delay_Req message;

[0016] a Pdelay_Req message processing section that records a reception time point t2 of a Pdelay_Req message transmitted from the lower device;

[0017] a Pdelay_Resp message processing section that saves the reception time point t2 of the Pdelay_Req message into a Pdelay_Resp message, and transmits the Pdelay_Resp message in which the reception time point t2 of the Pdelay_Req message is saved to the lower device;

[0018] a Pdelay_Resp_Follow_Up message processing section that saves a transmission time point t3 of the Pdelay_Resp message into a Pdelay_Resp_Follow_Up message, and transmits the Pdelay_Resp_Follow_Up message in which the transmission time point t3 of the Pdelay_Resp message is saved to the lower device;

[0019] a superior-side transmission delay calculation section that calculates a transmission delay time ptl between the superior device and the conversion device using a reception time point dtl of the Sync message, a transmission time point Tl of the superior device of the Sync message, a transmission time point T3 of the Delay_Req message, and a reception time point T4 of the Delay_Req message;

[0020] an internal processing time calculation section that calculates an internal processing time of the conversion device using the reception time point dtl of the Sync message and a transmission time point dt2 for relaying the Sync message; and

[0021] a total value holding section that holds a total value of the transmission delay time ptl between the superior device and the conversion device and the internal processing time of the conversion device in a CorrectionField of the Follow_Up message, and transmits the Follow_Up message in which the total value is held to the inferior device for relaying.

[0022] Effects of Invention

[0023] The conversion device of the present disclosure has a Delay_Req message processing section, a Delay_Resp message processing section, a superior-side transmission delay calculation section, and a total value holding section. Therefore, the conversion device of the present disclosure can perform time synchronization even in a case where two different transmission delay measurement methods such as End to End and Peer to Peer are used between a superior device and an inferior device that is synchronized in time with the superior device. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a diagram of Embodiment 1, and is a diagram showing the operation of the TC 101 that is Comparative Example 1 of the conversion device 100.

[0025] Figure 2 is a diagram of Embodiment 1, and is a diagram showing the operation of the TC 102 that is Comparative Example 2 of the conversion device 100.

[0026] Figure 3 is a diagram of Embodiment 1, and is a diagram showing the operation of the conversion device 100, and is a diagram showing the conversion of End to End to Peer to Peer.

[0027] Figure 4 is a diagram of Embodiment 1, and is a diagram showing the operation of the conversion device 100.

[0028] Figure 5 is a diagram of Embodiment 1, and is a diagram showing the operation of the conversion device 100. Figure 4the graphs at each time point.

[0029] Figure 6 is a graph of Embodiment 1, and is a graph showing a block structure of the conversion device 100.

[0030] Figure 7 is a graph of Embodiment 1, and is a graph showing a case of 1 step without a Follow_Up message.

[0031] Figure 8 is a graph of Embodiment 1, and is a graph showing a hardware structure of the conversion device 100.

[0032] Figure 9 is a graph of Embodiment 1, and is a graph showing a structure in which the function of the conversion device 100 is realized by hardware. DETAILED DESCRIPTION

[0033] In the description of the embodiments and the drawings, the same reference numerals are assigned to the same elements and corresponding elements. The description of the elements labeled with the same reference numerals is appropriately omitted or simplified. In the following embodiments, "unit" can be appropriately replaced with "circuit", "step", "process", "treatment", or "circuitry".

[0034] Embodiment 1

[0035] Hereinafter, the conversion device 100 of Embodiment 1 will be described with reference to the drawings. The conversion device 100 is a device that converts the transmission delay measurement method of a higher device into the transmission delay measurement method of a lower device in a case where the transmission delay measurement methods are different between the higher device that performs PTP communication and the lower device that performs PTP communication. In Embodiment 1, it is assumed that the higher device is the master device 200 and the lower device is the client device 300. Further, CF described below indicates "Correction Field" in a PTP message.

[0036] In Figure 1 , as Comparative Example 1 of the conversion device 100, a Transparent Clock 101 is described. In Figure 2 , as Comparative Example 2 of the conversion device 100, a Transparent Clock 102 is described. Hereinafter, the Transparent Clock is expressed as TC.

[0037] Figure 1 is a graph showing the operation of the TC 101 of Comparative Example 1. In Figure 1In this case, the master device 201 and the client device 301 implement a transmission delay measurement method on an end to end basis. The TC 101 transmits packets on an end to end basis. In Figure 1 In this case, messages are exchanged in the following manner.

[0038] <End to End Based Message Exchange>

[0039] Hereinafter, a 2-step (2step) is explained. In a 1-step (1step), the Follow_Up message shown by the dotted arrow is not used.

[0040] (1) In step S11, the master device 201 transmits a Sync message.

[0041] (2) In step S12, the master device 201 saves the transmission time T1 of the Sync message into a Follow_Up message and transmits it.

[0042] (3) In step S13, the TC 101 records the time dt1 at which the Sync message was received and the time dt2 at which the Sync message was transmitted.

[0043] (4) In step S14, the TC 101 saves the internal processing time = dt2 - dt1 as a processing time inside the device of the TC 101 (hereinafter referred to as internal processing time) in the CF of the Follow_Up message and transmits it.

[0044] (5) In step S15, the client device 301 records the time T2 at which the Sync message was received.

[0045] (6) In step S16, the client device 301 transmits a Delay_Req message, at which time the transmission time T3 is saved into the Delay_Req message and transmitted.

[0046] (7) In step S17, the TC 101 records the time dt3 at which the Delay_Req message was received and the time dt4 at which the Delay_Req message was transmitted.

[0047] (8) In step S18, the master device 201 records the time T4 at which the Delay_Req message was received.

[0048] (9) In step S19, the master device 201 transmits T4 carried in a Delay_Resp message.

[0049] (10) In step S20, the TC 101 saves the internal processing time = dt4 - dt3 of the TC 101 into the CF of the Delay_Resp message and transmits it.

[0050] <Offset Calculation Method Between Master Device 201 and Client Device 301>

[0051] The client device 301 can use "T1, T2, T3, T4, dt2-dt1, dt4-dt3" obtained through the exchange of the above messages to calculate the following offsets.

[0052] Offset = {(T2-T1-(dt2-dt1))-(T4-T3-(dt4-dt3))} / 2

[0053] By correcting the client device's time based on offset, the client device can synchronize its time with the master device.

[0054] In the case of step 1, the T1 stored in the Follow_Up message and the internal processing time = dt2-dt1 are carried in the Sync message and sent.

[0055] Figure 2 This is a diagram illustrating the operation of TC 102 in Comparative Example 2. Figure 2 In this system, the master device 202 and the client device 302 implement a transmission delay measurement method based on peer-to-peer (P2P) communication. TC 102 transmits packets based on P2P communication. Figure 2 In this context, messages are exchanged in the following manner.

[0056] <Peer-to-Peer Message Exchange>

[0057] The following explains step 2. In step 1, the Follow_Up message with a dashed arrow and the Pdelay_Resp_Follow_Up message with two dashed arrows are not used.

[0058] (1) In step S31, TC 102 sends the Pdelay_Req message to the master device 202 and records the sending time t1.

[0059] (2) In step S32, the main device 202 records the time t2 when the Pdelay_Req message is received.

[0060] (3) In step S33, the main device 202 sends a Pdelay_Resp message and records the sending time t3. At this time, the receiving time t2 of the Pdelay_Req message is saved into the Pdelay_Resp message and sent.

[0061] (4) In step S34, the master device 202 saves the time t3 into the Pdelay_Resp_Follow_Up message and transmits it.

[0062] (5) In step S35, the TC 102 records the time t4 at which the Pdelay_Resp message is received.

[0063] (6) In step S36, the TC 102 calculates the transmission delay time ptl between the master device 20 and the TC 102 using the respective times (tl, t2, t3, t4) by the following equation.

[0064] Transmission delay time ptl = { (t2-tl) + (t4-t3)} / 2

[0065] (7) In step S37, similarly, the client device 302 calculates the transmission delay time pt2 between the TC 102 and the client device 302. The same exchange as in steps S31 to S35 is performed between the TC 102 and the client device 302. The times tl to t4 of steps S31 to S35 correspond to the times t5 to t8 shown in FIG. 7. Figure 2

[0066] Transmission delay time pt2 = { (t6-t5) + (t8-t7)} / 2

[0067] (8) In step S38, the master device 202 transmits the Sync message.

[0068] (9) In step S39, the master device 202 transmits the transmission time tl of the Sync message in the Follow_Up message.

[0069] (10) In step S40, the TC 102 records the time dtl at which the Sync message is received and the time dt2 at which the Sync message is transmitted.

[0070] (11) In step S41, the TC 102 saves the sum ptl + (dt2-dtl) of the transmission delay time ptl between the master device 202 and the TC 102 and the internal processing time (dt2-dtl) of the TC 102 in the CF of the Follow_Up message and transmits it.

[0071] (12) The client device 302 calculates the time T2 of the client device to synchronize with the transmission time tl of the Sync message using the transmission delay time pt2 calculated in step S37 and the sum ptl + (dt2-dtl) saved in the CF of the Follow_Up message by the following equation.

[0072] ​T2 = T1 + pt1 + (dt2 - dt1) + pt2

[0073] The time T2 calculated by the above equation becomes a time synchronized with the master device 202.

[0074] In the case of 1 step, it is transmitted as follows.

[0075] The time T1 saved in the Follow_Up message and transmitted and the sum value (pt1 + (dt2 - dt1)) are carried in the Sync message and transmitted. In this case, the sum value is saved in the CF of the Sync message.

[0076] Further, the time t3 and the time t7 carried in the Pdelay_Resp_Follow_Up message and transmitted are saved in the CF of the Pdelay_Resp message and transmitted.

[0077] Figure 3 is a diagram illustrating an outline of the action of the conversion device 100 of Embodiment 1. In Figure 1 and Figure 2 , as comparative examples of the conversion device 100, an End to End-implemented TC 101 (Comparative Example 1) and a Peer to Peer-implemented TC 102 (Comparative Example 1) are explained. In the case where the master device uses the End to End-implemented transmission delay measurement method and the client device uses the Peer to Peer-implemented transmission delay measurement method, in the TC 101 and the TC 102, it is not possible to synchronize the times of the master device and the client device.

[0078] In contrast to this, even in the case where the master device uses the End to End-implemented transmission delay measurement method and the client device uses the Peer to Peer-implemented transmission delay measurement method, the conversion device 100 is able to synchronize the times of the master device and the client device. In Figure 3 , the transmission delay measurement method is converted from End to End to Peer to Peer using the conversion device 100. Thereby, even in the section of different transmission delay measurement methods, the client device 300 is able to synchronize the times with the master device 200.

[0079] According to the conversion device 100, it is not necessary to reform, set, and the like, the master device 200 and the client device 300, and only the conversion of the messages, rewriting of the values, by the conversion device 100. That is, in the master device 200, it is possible to directly use the master device 201 (End to End-implemented transmission delay measurement method) and the client device 301 (Peer to Peer-implemented transmission delay measurement method). Figure 1), the master device 201 uses an End to End based transmission delay measurement method. Further, in the client device 300, the client device 302 (Pdelay_Req message processing section 21, Pdelay_Resp message processing section 22, Pdelay_Resp_Follow_Up message processing section 23) can be used directly Figure 2 ), the master device 201 uses an End to End based transmission delay measurement method. Further, in the client device 300, the client device 302 (Pdelay_Req message processing section 21, Pdelay_Resp message processing section 22, Pdelay_Resp_Follow_Up message processing section 23) can be used directly

[0080] In addition, the time taken for the conversion processing of the conversion device 100 is added to the usual internal processing time to perform time synchronization. Therefore, there is no degradation in the precision of the time due to the conversion processing.

[0081] Figure 4 is a diagram illustrating details of the action of the conversion device 100 of Embodiment 1.

[0082] Figure 5 is a table illustrating Figure 4 each time shown in FIG. 8.

[0083] Figure 6 represents the block structure of the conversion device 100.

[0084] ***Explanation of the Structure***

[0085] The structure of the conversion device 100 will be described with reference to Figure 6 The structure of the conversion device 100 will be described with reference to

[0086] The Sync message processing section 11 is a first processing unit. The Follow_Up message processing section 12 is a second processing unit. The Delay_Req message processing section 13 is a third processing unit. The Delay_Resp message processing section 14 is a fourth processing unit. The Pdelay_Req message processing section 21 is a fifth processing unit. The Pdelay_Resp message processing section 22 is a sixth processing unit. The Pdelay_Resp_Follow_Up message processing section 23 is a seventh processing unit. The master device 200 is a superior device. The client device 300 is an inferior device. The CF processing section 60 is a total value holding section.

[0087] Further, each message processing section is described as the Sync processing section 11 hereinafter.

[0088] The functions of each constituent element are as follows.

[0089] (1) <Master side packet communication section 30M, client side packet communication section 30C>

[0090] The master side packet communication section 30M and the client side packet communication section 30C each transmit and receive PTP packets between the master device 200 and the client device 300.

[0091] (2) <Sync processing section 11>

[0092] The Sync message from the master device 200 is received, the reception time dt1 and the transmission time dt2 of the Sync message transmitted to the client device 300 are recorded, and the following processing is implemented.

[0093] (a) The reception time dt1 is transmitted to the superior side transmission delay calculation section 40,

[0094] (b) The reception time dt1 and the transmission time dt2 are transmitted to the internal processing time calculation section 50,

[0095] (c) The Sync message is transmitted to the CF processing section 60.

[0096] (3) <Follow_Up processing section 12>

[0097] The Follow_Up message is received from the master device 200 (the Follow_Up message transmission time T1 is held), and the Follow_Up message is transmitted to the CF processing section 60. Further, the transmission time T1 is extracted and transmitted to the superior side transmission delay calculation section 40.

[0098] (4) <Delay_Req processing section 13>

[0099] The Delay_Req processing section 13 implements the following processing.

[0100] (a) sends a Delay_Req message to the master device 200,

[0101] (b) records the transmission time T3 of the Delay_Req message,

[0102] (c) sends the transmission time T3 to the upper-side transmission delay calculation section 40.

[0103] (5) <Delay_Resp processing section 14>

[0104] The Delay_Resp processing section 14 performs the following processing.

[0105] (a) receives a Delay_Resp message from the master device 200 (saves the reception time T4 of the Delay_Req message),

[0106] (b) extracts the reception time T4 from the Delay_Resp message and sends it to the upper-side transmission delay calculation section 40.

[0107] (6) <Pdelay_Req processing section 21>

[0108] The Pdelay_Req processing section 21 performs the following processing.

[0109] (a) receives a Pdelay_Req message from the client device 300,

[0110] (b) records the reception time t2 of the Pdelay_Req message,

[0111] (c) sends the reception time t2 to the Pdelay_Resp processing section 22.

[0112] (7) <Pdelay_Resp processing section 22>

[0113] The Pdelay_Resp processing section 22 performs the following processing.

[0114] (a) saves the reception time t2 of the Pdelay_Req to a Pdelay_Resp message and sends it to the client device 300,

[0115] (b) records the transmission time t3 of the Pdelay_Resp message and sends it to the Pdelay_Resp_Follow_Up section 23.

[0116] (8) <Pdelay_Resp_Follow_Up processing section 23>

[0117] The Pdelay_Resp_Follow_Up processing section 23 performs the following processing.

[0118] (a) The transmission time t3 received from the Pdelay_Resp processing section 22 is saved into the Pdelay_Resp_Follow_Up message, and transmitted to the client apparatus 300. (9) <Upper-side transmission delay calculation section 40>

[0119] The upper-side transmission delay calculation section 40 performs the following processing.

[0120] (a) The transmission delay time ptl between the master apparatus 200 as the upper apparatus and the conversion apparatus 100 is calculated.

[0121] If the calculation formula is expressed with f, the transmission delay time ptl is calculated by the following formula, the details of which will be described later:

[0122] ptl = f (dtl, Tl, T3, T4).

[0123] (b) The transmission delay time ptl is transmitted to the CF processing section 60.

[0124] (10) <Internal processing time calculation section 50>

[0125] The internal processing time calculation section 50 performs the following processing.

[0126] (a) The internal processing time (dt2-dtl) of the conversion apparatus 100 is calculated using the reception time dtl and the transmission time dt2 received from the Sync processing section 11,

[0127] (b) The internal processing time (dt2-dtl) is transmitted to the CF processing section 60.

[0128] (11) <CF processing section 60>

[0129] The CF processing section 60 saves values into the CF of each message.

[0130] ***Explanation of actions***

[0131] Reference Figure 4 The actions of the conversion apparatus 100 will be described. The actions of the conversion apparatus 100 correspond to a conversion method. Further, the actions of the conversion apparatus 100 correspond to the processing performed by the conversion program 131.

[0132] <Exchange flow of messages>

[0133] In Figure 4 , the 2-step (2step) is described. In the 1-step (1step), the Follow_Up message and the Pdelay_Resp_Follow_Up message shown by the dotted arrow are not used. The 1-step (1step) is described inFigure 7 The following will be described later.

[0134] Communication is performed between the master device 200 and the conversion device 100 on an end to end basis. Between the network as a whole, that is, the master device 200 and the client device 300, a peer to peer method is used to synchronize the time of the client device 300 with the time of the master device 200.

[0135] <Step S101, Step S102>

[0136] In step S101, the master device 200 transmits a Sync message.

[0137] In step S102, the master device 200 saves the transmission time T1 of the Sync message into a Follow_Up message and transmits it. The following process A and process B are performed in parallel by the conversion device 100.

[0138] <Process A>

[0139] The following describes the process A. The process A is step S103A and step S104A.

[0140] <Step S103A>

[0141] The master side packet communication section 30M receives the Sync message. In step S103A, the Sync processing section 11 records the reception time dt1 of the Sync message, and transmits the Sync message to the client device 300 via the client side packet communication section 30C. The Sync processing section 11 records the transmission time dt2 of the Sync message to the client device 300.

[0142] <Step S104A>

[0143] The master side packet communication section 30M receives the Follow_Up message. The Follow_Up processing section 12 transmits the received Follow_Up message to the CF processing section 60. The CF processing section 60 saves the sum of the transmission delay time pt1 between the master device 200 and the conversion device 100 and the internal processing time (dt2-dt1) in the CF of the Follow_Up message, pt1+(dt2-dt1).

[0144] In step S104A, the CF processing section 60 transmits the Follow_Up message in which the above sum is registered to the client device 300 via the client side packet communication section 30C.

[0145] In addition, generally, the value of the CF of the Follow_Up message on an end to end basis is "dt2-dt1". Here, if the transmission time T1 of the Sync message is set to "0", the value of the CF of the Follow_Up message becomes "dt2".Figure 4 The exchange of the message whole of the master device 200 on the left side with the conversion device 100 is set to one group, and the transmission delay time pt1 uses the value found before the one group.

[0146] <Process B>

[0147] Process B is explained below. Process B is from step S105B to step S109B.

[0148] <Step S105B>

[0149] In step S105B, the Delay_Req processing section 13 sends the Delay_Req message to the master device 200 via the master side packet communication section 30M. At this time, the Delay_Req processing section 13 saves the transmission time T3 of the Delay_Req message into the Delay_Req message. Also, normally, the TC does not send the Delay_Req message, and only relays.

[0150] <Step S106B to Step S108B>

[0151] In step S106B, the master device 200 records the reception time T4 of the Delay_Req message.

[0152] In step S107B, the master device 200 saves the reception time T4 into the Delay_Resp message and sends it.

[0153] In step S108B, the Delay_Resp processing section 14 receives the Delay_Resp message via the master side packet communication section 30M and terminates the message.

[0154] Also, normally, the TC does not terminate the Delay_Resp message, and only relays. The Delay_Resp processing section 14 sends the reception time T4 to the upper side transmission delay calculation section 40.

[0155] <Step S109B>

[0156] In step S109B, the upper side transmission delay calculation section 40 calculates the transmission delay time pt1 between the master device 200 and the conversion device 100. The upper side transmission delay calculation section 40 calculates the transmission delay time pt1 by Formula 1.

[0157] pt1 = { (dt1 - T1) + (T4 - T3)} / 2 (Formula 1)

[0158] The above is Process B.

[0159] (1) In step S110, the client device 300 transmits a Pdelay_Req message to the conversion device 100, and records the transmission time point tl.

[0160] (2) In step S111, the Pdelay_Req processing section 21 records the reception time point t2 of the Pdelay_Req message.

[0161] (3) In step S112, the Pdelay_Resp processing section 22 transmits a Pdelay_Resp message, records the transmission time point t3, and at this time saves the reception time point t2 into the Pdelay_Resp message and transmits it.

[0162] (4) In step S113, the Pdelay_Resp_Follow_Up processing section 23 saves the transmission time point t3 in a Pdelay_Resp_Follow_Up message and transmits it.

[0163] (5) In step S114, the client device 300 records the reception time point t4 of the Pdelay_Resp message.

[0164] (6) In step S115, the client device 300 calculates the transmission delay time pt2 between the conversion device 100 and the client device 300 by using the transmission time point tl, the reception time point t2, the transmission time point t3, and the reception time point t4, by Formula 2.

[0165] Transmission delay time pt2 = { (t2 - tl) + (t4 - t3)} / 2 (Formula 2)

[0166] The client device 300 performs time synchronization according to Formula 3. The time point T2 is the reception time point of the Sync message in the client device 300.

[0167] T2 = Tl + ptl + (dt2 - dtl) + pt2 (Formula 3)

[0168] Figure 7 is a diagram showing the case of 1 step (1 step). In Figure 4 2 step (2 step) is shown, but in the case of 1 step (1 step), as shown in Figure 7 is the following action.

[0169] (1) The transmission time point Tl saved in the Follow_Up message transmitted is saved into the Sync message.

[0170] (2) (dt2 - dtl) saved in the CF of the Follow_Up message is carried in the CF of the Sync message as CF = ptl + (dt2 - dtl) and transmitted.

[0171] (3) The transmission time t3 saved in the Pdelay_Resp_Follow_Up message is carried in the CF of the Pdelay_Resp message and transmitted.

[0172] <Hardware structure of conversion device 100>

[0173] Figure 8 The hardware structure of the conversion device 100 is shown. Referring to Figure 8 The hardware structure of the conversion device 100 is described.

[0174] The conversion device 100 is a computer. The conversion device 100 has a processor 110. The conversion device 100 has a plurality of hardware in addition to the processor 110. The plurality of hardware is a main storage device 120, an auxiliary storage device 130, an input interface 140, an output interface 150, and a communication interface 160. The processor 110 is connected to the other hardware via a signal line 170 and controls the other hardware.

[0175] As functional elements, the conversion device 100 has a Sync processing section 11, a Follow_Up processing section 12, a Delay_Req processing section 13, a Delay_Resp processing section 14, a Pdelay_Req processing section 21, a Pdelay_Resp processing section 22, a Pdelay_Resp_Follow_Up processing section 23, a master side packet communication section 30M, a client side packet communication section 30C, an upper side transmission delay calculation section 40, an internal processing time calculation section 50, and a CF processing section 60.

[0176] The functions of the Sync processing section 11, the Follow_Up processing section 12, the Delay_Req processing section 13, the Delay_Resp processing section 14, the Pdelay_Req processing section 21, the Pdelay_Resp processing section 22, the Pdelay_Resp_Follow_Up processing section 23, the master side packet communication section 30M, the client side packet communication section 30C, the upper side transmission delay calculation section 40, the internal processing time calculation section 50, and the CF processing section 60 are implemented by a conversion program 131.

[0177] The processor 110 is a device that executes the conversion program 131. By the processor 110 executing the conversion program 131, the functions of the Sync processing section 11, the Follow_Up processing section 12, the Delay_Req processing section 13, the Delay_Resp processing section 14, the Pdelay_Req processing section 21, the Pdelay_Resp processing section 22, the Pdelay_Resp_Follow_Up processing section 23, the master side packet communication section 30M, the client side packet communication section 30C, the upper side transmission delay calculation section 40, the internal processing time calculation section 50, and the CF processing section 60 are realized. The processor 110 is an IC (Integrated Circuit) that performs arithmetic processing. A specific example of the processor 110 is a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or a GPU (Graphics Processing Unit).

[0178] A specific example of the main storage device 120 is an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory). The main storage device 120 holds the calculation results of the processor 110.

[0179] The auxiliary storage device 130 is a storage device that nonvolatilely stores data. A specific example of the auxiliary storage device 130 is an HDD (Hard Disk Drive). Alternatively, the auxiliary storage device 130 can be a removable recording medium. As the removable recording medium, there are an SD (registered trademark) memory card, a NAND flash memory, a floppy (registered trademark) disk, an optical disk, a compact disc, a Blu-ray (registered trademark) disc, and a DVD (Digital Versatile Disk). The auxiliary storage device 130 stores the conversion program 131.

[0180] The input interface 140 is a port that inputs data from each device. The output interface 150 is connected to various devices. The output interface 150 is a port that outputs data to various devices by the processor 110. The communication interface 160 is a communication port for the processor to communicate with the master device 200 and the client device 300.

[0181] The processor 110 loads the conversion program 131 from the auxiliary storage device 130 to the main storage device 120. The processor 110 reads in the loaded conversion program 131 from the main storage device 120 and executes. In the main storage device 120, an OS (Operating System) is stored in addition to the conversion program 131. The processor 110 executes the conversion program 131 while executing the OS. The conversion device 100 can also have a plurality of processors instead of the processor 110. The plurality of processors share the execution of the conversion program 131. Each processor is a device that executes the conversion program 131 as with the processor 110. Data, information, signal values, and variable values utilized, processed, or output by the conversion program 131 are stored in the main storage device 120, the auxiliary storage device 130, or a register or cache within the processor 110.

[0182] The conversion program 131 is a program that causes a computer to execute each process, each procedure, or each step of replacing "parts" of the Sync processing section 11, the Follow_Up processing section 12, the Delay_Req processing section 13, the Delay_Resp processing section 14, the Pdelay_Req processing section 21, the Pdelay_Resp processing section 22, the Pdelay_Resp_Follow_Up processing section 23, the master-side packet communication section 30M, the client-side packet communication section 30C, the upper-side transmission delay calculation section 40, the internal processing time calculation section 50, and the CF processing section 60 with "processes", "procedures", or "steps".

[0183] In addition, the conversion method is a method performed by the conversion device 100 as a computer executing the conversion program 131.

[0184] The conversion program 131 can be provided saved in a recording medium readable by a computer, or can be provided as a program product.

[0185] Supplement to hardware structure

[0186] In Figure 8 , the functions of the conversion device 100 are implemented by software. However, the functions of the conversion device 100 can also be implemented by hardware.

[0187] Figure 9 A structure in which the functions of the conversion device 100 are implemented by hardware. Figure 9The electronic circuit 500 is a dedicated electronic circuit that implements the functions of the Sync processing section 11, the Follow_Up processing section 12, the Delay_Req processing section 13, the Delay_Resp processing section 14, the Pdelay_Req processing section 21, the Pdelay_Resp processing section 22, the Pdelay_Resp_Follow_Up processing section 23, the master-side packet communication section 30M, the client-side packet communication section 30C, the upper-side transmission delay calculation section 40, the internal processing time calculation section 50, and the CF processing section 60 of the conversion device 100.

[0188] The electronic circuit 500 is connected to the signal line 501. Specifically, the electronic circuit 500 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, or an FPGA. The GA is an abbreviation for Gate Array.

[0189] The ASIC is an abbreviation for Application Specific Integrated Circuit. The FPGA is an abbreviation for Field-Programmable Gate Array. The functions of the structural elements of the conversion device 100 can be implemented by one electronic circuit or can be distributed among a plurality of electronic circuits. Furthermore, a part of the functions of the structural elements of the conversion device 100 can be implemented by an electronic circuit, and the remaining functions can be implemented by software.

[0190] The processor 110 and the electronic circuit 500 are also respectively referred to as a processing line or a line. In the conversion device 100, the functions of the Sync processing section 11, the Follow_Up processing section 12, the Delay_Req processing section 13, the Delay_Resp processing section 14, the Pdelay_Req processing section 21, the Pdelay_Resp processing section 22, the Pdelay_Resp_Follow_Up processing section 23, the master-side packet communication section 30M, the client-side packet communication section 30C, the upper-side transmission delay calculation section 40, the internal processing time calculation section 50, and the CF processing section 60 can also be implemented by a line.

[0191] ***Effects of Embodiment 1***

[0192] As one of the reasons that time synchronization cannot be performed between different configuration files, there is a difference in the transmission delay measurement method (End to End, Peer to Peer).

[0193] However, by using the conversion device 100 of Embodiment 1, the client device 300 is able to perform time synchronization with the master device 200 even in a case where the transmission delay measurement methods are different between the master device 200 and the client device 300.

[0194] Thus, by using the conversion device 100, it is possible to connect between profiles whose transmission delay measurement methods are different, and therefore, it is not necessary to separately construct a time distribution network, and it is possible to reduce equipment costs.

[0195] The above describes Embodiment 1 of the present disclosure. Several combinations of Embodiment 1 can also be implemented. Furthermore, any one or several of them can be implemented partially. In addition, the present disclosure is not limited to the above-described Embodiment 1, and various changes can be made as necessary.

[0196] Explanation of Reference Numerals

[0197] 11: Sync processing section; 12: Follow_Up processing section; 13: Delay_Req processing section; 14: Delay_Resp processing section; 21: Pdelay_Req processing section; 22: Pdelay_Resp processing section; 23: Pdelay_Resp_Follow_Up processing section; 30M: Master side packet communication section; 30C: Client side packet communication section; 40: Upper side transmission delay calculation section; 50: Internal processing time calculation section; 60: CF processing section; 100: Conversion device; 101, 102: TC; 110: Processor; 120: Main storage device; 130: Auxiliary storage device; 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, which converts the transmission delay measurement method of the upper-level device into the transmission delay measurement method of the lower-level device when the transmission delay measurement methods of the upper-level device and the lower-level device performing PTP (Precision Time Protocol) communication are different, the conversion device comprising: The Sync message processing unit receives the Sync message sent from the host device and records the reception time dt1, and records the transmission time dt2 of the Sync message when it is sent to the slave device for relay purposes. The Follow_Up message processing unit extracts the transmission time T1 of the Sync message from the transmission time T1 of the host device that stores the Sync message and from the Follow_Up message sent by the host device. The Delay_Req message processing unit sends a Delay_Req message to the host device and records the sending time T3 of the Delay_Req message. The Delay_Resp message processing unit extracts the reception time T4 of the Delay_Req message from the Delay_Req message stored in the storage and from the Delay_Resp message sent by the host device. The Pdelay_Req message processing unit records the reception time t2 of the Pdelay_Req message sent from the lower-level device; The Pdelay_Resp message processing unit saves the reception time t2 of the Pdelay_Req message into the Pdelay_Resp message, and sends the Pdelay_Resp message containing the reception time t2 of the Pdelay_Req message to the lower device. The Pdelay_Resp_Follow_Up message processing unit saves the sending time t3 of the Pdelay_Resp message into the Pdelay_Resp_Follow_Up message, and sends the Pdelay_Resp_Follow_Up message containing the sending time t3 of the Pdelay_Resp message to the lower-level device. The upper-side transmission delay calculation unit uses the reception time dt1 of the Sync message, the transmission time T1 of the upper-side device of the Sync message, the transmission time T3 of the Delay_Req message, and the reception time T4 of the Delay_Req message to calculate the transmission delay time pt1 between the upper-side device and the conversion device. An internal processing time calculation unit calculates the internal processing time of the conversion device using the receiving time dt1 of the Sync message and the sending time dt2 for relaying the Sync message; and The total value storage unit stores the total value of the transmission delay time pt1 between the host device and the conversion device and the internal processing time of the conversion device in the CorrectionField of the Follow_Up message, and sends the Follow_Up message containing the total value to the lower device for relay purposes.

2. A conversion program that causes a conversion device, acting as a computer, to perform processing, wherein the conversion device converts the transmission delay measurement method of the upper-level device to the transmission delay measurement method of the lower-level device when the transmission delay measurement methods between the upper-level device performing PTP (Precision Time Protocol) communication and the lower-level device performing the PTP communication differ, the processing comprising: Sync message processing: receiving the Sync message sent from the host device and recording the receiving time dt1, and recording the sending time dt2 of the Sync message when it is sent to the slave device for relay purposes; Follow_Up message processing: Extract the transmission time T1 of the Sync message from the transmission time T1 of the host device that stores the Sync message and from the Follow_Up message sent by the host device; Delay_Req message processing: Send the Delay_Req message to the host device and record the sending time T3 of the Delay_Req message; Delay_Resp message processing: Extract the reception time T4 of the Delay_Req message from the Delay_Req message that is stored and from the Delay_Resp message sent by the host device; Pdelay_Req message processing, recording the reception time t2 of the Pdelay_Req message sent from the lower device; The Pdelay_Resp message processing method saves the reception time t2 of the Pdelay_Req message into the Pdelay_Resp message and sends 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 method saves the sending time t3 of the Pdelay_Resp message into the Pdelay_Resp_Follow_Up message, and sends the Pdelay_Resp_Follow_Up message containing the sending time t3 of the Pdelay_Resp message to the lower-level device. The upper-side transmission delay calculation process uses the receiving time dt1 of the Sync message, the sending time T1 of the Sync message by the upper-level device, the sending time T3 of the Delay_Req message, and the receiving time T4 of the Delay_Req message to calculate the transmission delay time pt1 between the upper-level device and the conversion device. The internal processing time is calculated using the receiving time dt1 of the Sync message and the sending time dt2 for relaying the Sync message; and The total value is saved in the CorrectionField of the Follow_Up message, which stores the total value of the transmission delay time pt1 between the host device and the conversion device and the internal processing time of the conversion device. The Follow_Up message containing the total value is then sent to the lower device for relay purposes.

3. A conversion method, wherein a conversion device, acting as a computer, performs the following steps: When the transmission delay measurement methods of a host device performing PTP (Precision Time Protocol) communication and a slave device performing the PTP communication differ, the conversion device converts the transmission delay measurement method of the host device to the transmission delay measurement method of the slave device, the steps comprising: The Sync message processing steps include receiving the Sync message sent from the host device and recording the receiving time dt1, and recording the sending time dt2 of the Sync message when it is sent to the slave device for relay purposes. The Follow_Up message processing steps involve extracting the transmission time T1 of the Sync message from the transmission time T1 of the host device that stores the Sync message and from the Follow_Up message sent by the host device. The Delay_Req message processing steps include sending a Delay_Req message to the host device and recording the sending time T3 of the Delay_Req message. The Delay_Resp message processing steps involve extracting the reception time T4 of the Delay_Req message from the Delay_Req message that is saved and sent by the host device. The Pdelay_Req message processing steps record the reception time t2 of the Pdelay_Req message sent from the lower-level device; The Pdelay_Resp message processing step involves saving the reception time t2 of the Pdelay_Req message into the 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 steps include saving the sending time t3 of the Pdelay_Resp message into the Pdelay_Resp_Follow_Up message, and sending the Pdelay_Resp_Follow_Up message containing the sending time t3 of the Pdelay_Resp message to the lower-level device. The upper-side transmission delay calculation step uses the receiving time dt1 of the Sync message, the sending time T1 of the Sync message by the upper-level device, the sending time T3 of the Delay_Req message, and the receiving time T4 of the Delay_Req message to calculate the transmission delay time pt1 between the upper-level device and the conversion device. The internal processing time calculation step uses the receiving time dt1 of the Sync message and the sending time dt2 used to relay the Sync message to calculate the internal processing time of the conversion device; and The total value saving step involves saving the total value of the transmission delay time pt1 between the host device and the conversion device and the internal processing time of the conversion device in the CorrectionField of the Follow_Up message, and sending the Follow_Up message containing the total value to the lower device for relay purposes.

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