Communication device and communication method

Abstract

This communication device (10) comprises: an identification unit (12) that continuously identifies a profile used by a counterpart device (1, 2), the profile being included in a time synchronization signal acquired from the counterpart device (1, 2) and being based on information relating to transmission / reception of the time synchronization signal and to a method of time synchronization that correspond to one profile from among a plurality of profiles; and an assessment unit (14) that, on the basis of a past profile identified by the identification unit (12) and a current profile identified by the identification unit (12), assesses whether or not there is a change in the profile used by the counterpart device (1, 2).

Description

[Technical Field]

[0001] The present disclosure relates to a communication device and a communication method. [Background technology]

[0002] One known method for time synchronization between communication devices on a network is the Precision Time Protocol (PTP) (see, for example, Non-Patent Document 1). In PTP, a Grand Master Clones (GMC) as a higher-level device and Clients as lower-level devices are connected via a network, and the Clients synchronize their internal time with the reference time distributed from the GMC. Specifically, the GMC receives a Global Navigation Satellite System (GNSS) signal to obtain the reference time. By transmitting and receiving a signal (time synchronization signal) between the GMC and the Clients, the Clients synchronize their internal time with the reference time distributed from the GMC.

[0003] PTP has multiple methods (profiles) that differ in the required parameters and time information formats depending on the industry and application in which it is used. When different profiles are required for different clients, currently, as shown in Figure 14, a separate network is provided for each client, and time synchronization is performed for each network by sending and receiving time synchronization signals between the GMC and client. However, in the future, it is expected that time synchronization with multiple clients will be performed via a single network using a GMC that can support multiple profiles, as shown in Figure 15. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems, IEEE Std 158-2019 Summary of the Invention [Problem to be solved by the invention]

[0005] As shown in FIG. 15, when multiple profiles are supported, it is necessary to identify the profile used by the opposing device, which is a communication device opposite via a network.

[0006] In PTP, a value called "profileIdentifier" is set as information to identify each profile. PTP also specifies a mechanism for requesting the profileIdentifier of the other device using management messages, and for returning the profileIdentifier in response to the request. Using this mechanism, the profile used by the other device can be identified. However, because implementation of the management message mechanism is optional for each profile, or because it is considered a feature requiring further study, it is not necessarily implemented in all commercially available devices. Furthermore, the profile used by the other device may change due to a configuration change on the other device during operation, or a profile error may occur due to a software error on the device. In such cases, it is necessary to detect changes in the profile used by the other device.

[0007] The purpose of the present disclosure, made in consideration of the above-mentioned problems, is to provide a communication device and a communication method that can identify the profile used by the opposing device regardless of the implementation status of the device, and further detect changes in the profile used by the opposing device. [Means for solving the problem]

[0008] In order to solve the above problem, the communication device disclosed herein is a communication device that performs time synchronization with an opposing communication device, that is, an opposing device, by sending and receiving a time synchronization signal according to one of a plurality of profiles, and is equipped with an identification unit that continuously identifies the profile to be used with the opposing device based on information regarding the sending and receiving of the time synchronization signal according to one of the plurality of profiles and the method of the time synchronization, which information is included in the time synchronization signal obtained from the opposing device, and a determination unit that determines whether or not the profile used with the opposing device has changed based on a past profile identified by the identification unit and a current profile identified by the identification unit.

[0009] In addition, in order to solve the above problem, the communication method disclosed herein is a communication method by a communication device that performs time synchronization with an opposing communication device, that is, an opposing device, by sending and receiving a time synchronization signal according to one of a plurality of profiles, and includes the steps of: acquiring the time synchronization signal from the opposing device; continuously identifying a profile to be used by the opposing device based on information contained in the acquired time synchronization signal regarding the sending and receiving of a time synchronization signal according to one of the plurality of profiles and the method of the time synchronization; and determining whether or not there has been a change in the profile used by the opposing device based on the identified past profile and the identified current profile. [Effects of the Invention]

[0010] According to the communication device and communication method disclosed herein, it is possible to identify the profile used by the opposing device and further detect changes in the profile used by the opposing device regardless of the implementation status of the device. [Brief explanation of the drawings]

[0011] [Figure 1A] 1 is a diagram illustrating time synchronization by PTP (E2E) to which a communication device according to the present disclosure is applied. [Figure 1B]1 is a diagram for explaining time synchronization by PTP (P2P) to which a communication device according to the present disclosure is applied. [Figure 2A] 1 is a diagram illustrating an example of the configuration of a PTP-based time synchronization system to which a communication device according to the present disclosure is applied. [Figure 2B] FIG. 10 is a diagram illustrating another example configuration of a PTP-based time synchronization system to which a communication device according to the present disclosure is applied. [Figure 3] 1 is a diagram illustrating a configuration example of a communication device according to a first embodiment of the present disclosure. [Figure 4] 4 is a flowchart showing an example of the operation of the communication device shown in FIG. 3. [Figure 5] FIG. 1 is a diagram illustrating multiple profiles in PTP. [Figure 6] FIG. 10 is a diagram illustrating an example of classification of a plurality of profiles. [Figure 7A] FIG. 10 is a diagram illustrating an example of the operation of a master and a client when adjusting a communication rate between the master and the client at the start of communication in PTP (E2E). [Figure 7B] FIG. 10 is a diagram illustrating an example of the operation of a master and a client when the communication rate is not adjusted between the master and the client at the start of communication in PTP (E2E). [Figure 7C] FIG. 10 is a diagram illustrating another example of the operation of the master and the client when the communication rate is not adjusted between the master and the client at the start of communication in PTP (E2E). [Figure 8A] FIG. 10 is a diagram illustrating an example of the operation of a master and a client when adjusting a communication rate between the master and the client at the start of communication in PTP (P2P). [Figure 8B] FIG. 10 is a diagram illustrating an example of the operation of a master and a client when the communication rate is not adjusted between the master and the client at the start of communication in PTP (E2E). [Figure 9A] 10 is a flowchart showing an example of the operation of the identification unit in the case of L2 / lower device / passive. [Figure 9B] 10 is a flowchart illustrating an example of the operation of the identification unit in the case of L3 / lower-level device / passive. [Figure 9C] 10 is a flowchart illustrating an example of the operation of the identification unit in the case of L2 / higher-level device / passive. [Figure 9D] 10 is a flowchart illustrating an example of the operation of the identification unit in the case of L3 / higher-level device / passive. [Figure 10A] 10 is a flowchart showing an example of the operation of the identification unit in the case of L2 / lower device / active. [Figure 10B] 10 is a flowchart showing an example of the operation of the identification unit in the case of L3 / lower device / active. [Figure 10C] 10 is a flowchart showing an example of the operation of the identification unit in the case of L2 / higher-level device / active. [Figure 10D] 10 is a flowchart showing an example of the operation of the identification unit in the case of L3 / higher-level device / active. [Figure 11] FIG. 10 is a diagram illustrating a configuration example of a communication device according to a second embodiment of the present disclosure. [Figure 12] FIG. 10 is a diagram illustrating a configuration example of a communication device according to a third embodiment of the present disclosure. [Figure 13] FIG. 2 is a diagram illustrating an example of a hardware configuration of a communication device according to the present disclosure. [Figure 14] FIG. 1 is a diagram for explaining current time synchronization using PTP. [Figure 15] FIG. 1 is a diagram for explaining assumed time synchronization by PTP. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] (First embodiment) First, we will explain time synchronization using PTP, to which a communication device and a communication method according to the present disclosure are applied. Time synchronization using PTP includes the E2E (End-to-End) method and the P2P (Peer-to-Peer) method. Below, we will explain both the E2E time synchronization (PTP(E2E)) and the P2P time synchronization (PTP(P2P)).

[0014] FIG. 1A is a diagram for explaining time synchronization by PTP (E2E).

[0015] As shown in Fig. 1A, in PTP, time synchronization is achieved by transmitting and receiving time synchronization signals between a Master as a higher-level device and a Client as a lower-level device. The Master has a function (Master function) of acquiring a reference time and distributing the acquired reference time to a lower-level device for synchronization. The Master is, for example, the GMC described above. The Client has a function (Client function) of synchronizing its internal device time with the reference time distributed from the Master.

[0016] At time T1, the Master sends a Sync message (hereinafter simply referred to as "Sync"). The Master includes time T1, which is the time at which Sync was sent, in Sync. This allows the Client to know the time T1 at which Sync was sent by the Master. When the Client receives Sync sent from the Master at time T2, it sends a Delay_req message (hereinafter simply referred to as "Delay_req") to the Master at time T3. When the Master receives Delay_req at time T4, it sends a Delay_resp message (hereinafter simply referred to as "Delay_resp") to the Client. The Master includes time T4, which is the time at which Delay_req was received, in Delay_resp. This allows the Client to know the time T4 at which Delay_req was received by the Master.

[0017] The transmission delay time from the Master to the Client is D1, the transmission delay time from the Client to the Master is D2, and the delay time between the Master and the Client is D. If D=D1=D2, the Client can calculate the delay time D using the following formula. D=((T4-T3)+(T2-T1)) / 2

[0018] Based on the calculated delay time D, the client can calculate the time difference Δt between the master and the client using the following formula: Δt=T2-(T1+D)

[0019] The client can synchronize the internal time of the device with the reference time distributed from the master by correcting the internal time of the device based on the calculated time difference Δt.

[0020] Next, we will explain time synchronization using PTP (P2P).

[0021] FIG. 1B is a diagram for explaining time synchronization by PTP (P2P).

[0022] At time t1, the Client sends a Pdelay_req message (hereinafter simply referred to as "Pdelay_req"). When the Master receives the Pdelay_req sent from the Client at time t2, it sends a Pdelay_resp message (hereinafter simply referred to as "Pdelay_resp") to the Client at time t3. The Master includes in the Pdelay_resp the difference (t3-t2) between time t3, which is the time when the Pdelay_resp was sent, and time t2, which is the time when the Pdelay_req was received. The Client receives the Pdelay_resp at time t4. After sending the Pdelay_resp, the Master sends a Sync at time t5. The Master includes time t5, which is the time when the Sync was sent, in the Sync. The Client receives the Sync sent from the Master at time t6.

[0023] The response time from when the client sends Pdelay_req until it receives Pdelay_resp is d1, and the response processing time from when the master receives Pdelay_req until it sends Pdelay_resp is d2 (= t3 - t2). If D = D1 = D2, the client can calculate the delay time D using the following formula. D=(d1-d2) / 2=((t4-t1)-(t3-t2)) / 2

[0024] Based on the calculated delay time D, the client can calculate the time difference Δt between the master and the client using the following formula: Δt=t6-(t5+D)

[0025] The client can synchronize the internal time of the device with the reference time distributed from the master by correcting the internal time of the device based on the calculated time difference Δt.

[0026] Next, an overview of the communication device 10 according to this embodiment will be described with reference to FIGS. 2A and 2B. FIG. 2A is a diagram showing an example of the configuration of a time synchronization system based on PTP to which the communication device 10 according to this embodiment is applied. FIG. 2B is a diagram showing another example of the configuration of a time synchronization system based on PTP to which the communication device 10 according to this embodiment is applied. The communication device 10 shown in FIGS. 2A and 2B performs time synchronization with opposite communication devices 1 and 2 by transmitting and receiving a time synchronization signal corresponding to one of multiple profiles defined by PTP. In addition, the communication device 10 determines whether or not the profile used by the opposite devices 1 and 2 has changed.

[0027] In the time synchronization system shown in Fig. 2A, communication device 10 is opposite to opposite device 2, and identifies one profile to be used by opposite device 2 from multiple profiles described below, and determines whether the profile used by opposite device 2 has changed. The profile used by opposite device 2 is a profile related to the transmission of a time synchronization signal in the direction from opposite device 2 to communication device 10. Communication device 10 performs time synchronization with opposite device 2 using the identified profile (distributes reference time to opposite device 2). That is, in Fig. 2A, communication device 10 is a higher-level device having a Master function, and opposite device 2 is a lower-level device having a Client function.

[0028] In the time synchronization system shown in Fig. 2B, communication device 10 is connected to opposite device 1, and identifies one profile to be used by opposite device 1 from multiple profiles described below, and determines whether the profile used by opposite device 1 has changed. The profile used by opposite device 1 is a profile related to the transmission of a time synchronization signal in the direction from opposite device 1 to communication device 10. Communication device 10 performs time synchronization with opposite device 1 using the identified profile (synchronizing its internal device time with the time distributed from opposite device 1). That is, in Fig. 2B, communication device 10 is a lower-level device with a client function, and opposite device 1 is a higher-level device with a master function.

[0029] In this way, the communication device 10 according to the present embodiment may be a higher-level device having a Master function, or may be a lower-level device having a Client function.

[0030] FIG. 3 is a diagram showing an example of the configuration of the communication device 10 according to this embodiment.

[0031] As shown in FIG. 3, the communication device 10 according to this embodiment includes a communication interface 11, an identification unit 12, a time synchronization unit 13, and a determination unit 14.

[0032] The communication interface 11 transmits and receives various signals for time synchronization (time synchronization signals) via the network with the counterpart devices 1 and 2. That is, when the communication device 10 is a higher-level device with a Master function (FIG. 2A), the communication interface 11 transmits and receives time synchronization signals with the counterpart device 2, which is a lower-level device. When the communication device 10 is a lower-level device with a Client function (FIG. 2B), the communication interface 11 transmits and receives time synchronization signals with the counterpart device 1, which is a higher-level device.

[0033] The identification unit 12 continuously identifies the profiles used by the opposite devices 1 and 2 based on information included in the time synchronization signals acquired from the opposite devices 1 and 2. Here, the identification unit 12 identifies the profiles based on information included in the time synchronization signals, regarding the transmission and reception of time synchronization signals and the time synchronization method corresponding to each of the multiple profiles. Unlike the profileIdentifier exchanged using the management message described above, this information is always included in the time synchronization signals exchanged between the Master and the Client for time synchronization. By using this information, the identification unit 12 can identify the profiles used by the opposite devices 1 and 2 regardless of the device implementation. Continuously identifying the profiles means identifying the profiles multiple times, for example, at predetermined time intervals or each time a new time synchronization signal is received. The identification unit 12 continuously identifies the profiles used by the opposite devices 1 and 2 based on the information included in the time synchronization signals acquired from the opposite devices 1 and 2 described above. The identification unit 12 outputs the results of identifying the profiles used by the opposite devices 1 and 2 to the determination unit 14.

[0034] The time synchronization unit 13 transmits and receives time synchronization signals to and from the opposing devices 1 and 2, and performs processing for the communication device 10 to synchronize its time with the opposing devices 1 and 2. When the communication device 10 is a higher-level device, the time synchronization unit 13 acquires a reference time and performs processing for synchronizing the internal time of the opposing device 2 with the reference time. When the communication device 10 is a lower-level device, the time synchronization unit 13 performs processing for synchronizing the internal time of the device with the reference time distributed from the opposing device 1.

[0035] The time synchronization unit 13 transmits a time synchronization signal (first time synchronization signal) to the opposing devices 1 and 2 via the communication interface 11 under the control of the identification unit 12. The identification unit 12 receives a time synchronization signal (second time synchronization signal) transmitted from the opposing devices 1 and 2 in response to the transmission of the time synchronization signal (first time synchronization signal) by the time synchronization unit 13, and thereby identifies the profile to be used by the opposing devices 1 and 2 based on the information included in the received time synchronization signal.

[0036] The determination unit 14 determines whether the profile used by the opposite device 1, 2 has changed based on the past profile identified by the identification unit 12 and the current profile identified by the identification unit 12. Specifically, the determination unit 14 detects a change in the profile used by the opposite device 1, 2 based on whether the past profile and the current profile match. For example, the determination unit 14 determines that the profile used by the opposite device 1, 2 has changed if a mismatch between the past profile and the current profile is detected three times in a row. By determining that the profile used by the opposite device 1, 2 has changed based on multiple mismatch detections in this manner, the occurrence of erroneous determinations due to errors can be reduced. However, if a change in the profile used by the opposite device 1, 2 is detected based on multiple mismatch detections, it takes longer to detect the change after the profile has changed. Therefore, the number of times a mismatch between the past profile and the current profile must be detected before it is determined that the profile used by the opposite device 1, 2 has changed may be determined according to required conditions, such as the time required to detect a profile change and the accuracy of the detection.

[0037] FIG. 4 is a flowchart showing an example of the operation of the communication device 10 according to the present embodiment, and is a diagram for explaining a communication method by the communication device 10 according to the present embodiment.

[0038] The identification unit 12 acquires the time synchronization signals from the associated devices 1 and 2 via the communication interface 11 (step S11). As will be described in detail later, the identification unit 12 passively or actively acquires the time synchronization signals from the associated devices 1 and 2.

[0039] The identification unit 12 continuously identifies the profile to be used by the opposing devices 1 and 2 based on information contained in the acquired time synchronization signal regarding the method of transmitting and receiving the time synchronization signal and the time synchronization method according to one of multiple profiles (step S12).

[0040] The determination unit 14 determines whether or not the profiles used by the opposed devices 1 and 2 have changed, based on the past profile identified by the identification unit 12 and the current profile identified by the identification unit 12 (step S13). Specifically, the determination unit 14 determines whether or not the profiles used by the opposed devices 1 and 2 have changed, based on whether or not the past profile and the current profile match.

[0041] Unlike the profileIdentifier exchanged using the management message described above, information regarding the transmission and reception of time synchronization signals according to the profile and the method of time synchronization is information that is always included in the time synchronization signals transmitted and received between the Master and the Client in order to perform time synchronization. By using such information, the communication method according to this embodiment makes it possible to identify the profiles used by the opposing devices 1 and 2 regardless of the implementation of the devices. Furthermore, by continuously identifying the profiles used by the opposing devices 1 and 2, it is possible to detect changes in the profiles used by the opposing devices based on past profiles and current profiles.

[0042] Next, a description will be given of details of how the communication device 10 according to this embodiment identifies profiles to be used by the associated devices 1 and 2. First, an example of multiple profiles that are candidates to be used by the associated devices 1 and 2 will be described with reference to FIG.

[0043] Candidate profiles include, for example, the default profile specified in IEEE1588-2008, telecom profiles (G.8265.1 profile, G.8275.1 profile, G.8275.2 profile) customized for communication by the International Telecommunication Union Telecommunication Standardization sector (ITU-T), a power profile for controlling smart grids or power systems, an industrial profile (IEEE802.1 AS profile) for autonomous driving, a video profile (SMPTE2059-2 profile) used for video Internet Protocol (IP) communication, and an enterprise profile for finance, as shown in Fig. 5. Note that in the SMPTE2059-2 profile in Fig. 5, multicast is set as the communication method and E2E is set as the PTP method, but the present invention is not limited to this, and unicast / E2E, unicast / P2P, or multicast / P2P may also be set.

[0044] In the following, the Default profile, G.8275.1 profile, G.8275.2 profile, Power profile, IEEE802.1 AS profile, and SMPTE2059-2 profile are considered to be candidate profiles to be used by the opposite devices 1 and 2. For simplicity of description, the Default profile will be represented as "D", the G.8275.1 profile as "T1", the G.8275.2 profile as "T2", the Power profile as "P", the IEEE802.1 AS profile as "AS", and the SMPTE2059-2 profile as "S". An example of identifying the profile to be used by the opposite devices 1 and 2 from these six profiles will be explained below.

[0045] 6, the six profiles described above can be classified based on whether the communication layer is L2 or L3 (L2 / L3), whether the destination address of the time synchronization signal is a unicast address or a multicast address (Uni / Multi), whether the communication rate is adjusted between the communication device 10 and the opposite devices 1 and 2 when the destination address is a unicast address (presence or absence of unicast negotiation), and the time synchronization method (E2E / P2P).The identification unit 12 uses such classification to identify the profile to be used by the opposite devices 1 and 2.

[0046] Information relating to the transmission and reception of time synchronization signals, such as information indicating whether the destination address of the time synchronization signal is a unicast address or a multicast address and information indicating whether the communication rate is adjusted between the communication device 10 and the opposed devices 1 and 2, can be ascertained from the time synchronization signals transmitted and received between the communication device 10 and the opposed devices 1 and 2. Information relating to the time synchronization method, such as whether the time synchronization method is E2E or P2P, can be ascertained from the time synchronization signals transmitted and received between the communication device 10 and the opposed devices 1 and 2. By using such information, the communication device 10 according to this embodiment can identify the profiles used by the opposed devices 1 and 2, regardless of the implementation of the devices.

[0047] The following will specifically describe how the identifying unit 12 identifies the profiles used by the opposing devices 1 and 2.

[0048] As described above, the communication device 10 may be either a higher-level device or a lower-level device. Therefore, when the communication device 10 is a higher-level device, it identifies a profile used by the opposite device 2, which is a lower-level device. When the communication device 10 is a lower-level device, it identifies a profile used by the opposite device 1, which is a higher-level device. Furthermore, the operation of the communication device 10 and the opposite devices 1 and 2 differs depending on whether the PTP method is E2E or P2P and whether the communication rate between the communication device 10 and the opposite devices 1 and 2 is adjusted. As described above, the identification unit 12 identifies the profile used by the opposite devices 1 and 2 using information included in a time synchronization signal transmitted and received between the communication device 10 and the opposite devices 1 and 2. Here, the time synchronization signal used by the identification unit 12 to identify the profile differs depending on the target for identifying the profile and the operation of the communication device 10 and the opposite devices 1 and 2. Therefore, first, examples of time synchronization signals used to identify the profile depending on the target for identifying the profile and the operation of the communication device 10 and the opposite devices 1 and 2 will be described.

[0049] 7A, 7B, and 7C are diagrams showing an example of the operation of the Master and Client at the start of communication in PTP (E2E). FIG. 7A is a diagram showing an example of the operation of the Master and Client when the communication rate is adjusted between the Master and Client. FIG. 7B is a diagram showing an example of the operation of the Master and Client when the communication rate is not adjusted between the Master and Client (when communication is started at a preset communication rate). FIG. 7C is a diagram showing another example of the operation of the Master and Client when the communication rate is not adjusted between the Master and Client (when communication is started at a preset communication rate).

[0050] As shown in FIG. 7A, when adjusting the communication rate between the Master and the Client, the Client sends a request (Signaling (request)) for adjusting the communication rate. The Master sends an acknowledgement (Signaling (acknowledge)) to the request from the Client, and then sends an allocation communication grant (Signaling (grant)). After that, the Master sends an Announce to notify quality information such as time synchronization accuracy, and then sends a Sync. In response to the Sync from the Master, the Client sends a Delay_req to the Master. The operation shown in FIG. 7A is the operation when a unicast address is set as the destination address and unicast negotiation is performed.

[0051] FIG. 7B shows the case where the Client starts communication autonomously. In this case, the Client sends a Delay_req to the Master. On the other hand, FIG. 7C shows the case where the Client does not start communication autonomously. In this case, the Master sends an Announce message (hereinafter simply referred to as "Announce") and then sends a Sync. In response to the Sync from the Master, the Client sends a Delay_req to the Master. The operations shown in FIGS. 7B and 7C are the operations when a unicast address is set as the destination address and unicast negotiation is not performed, and when a multicast address is set as the destination address.

[0052] When the communication device 10 is the Master in FIG. 7A, the communication device 10 can identify the profile to be used by the opposite device 2 by using a Signaling (request) that is a time synchronization signal that is first received from the opposite device 2 that is the Client.

[0053] When the communication device 10 is the Master in FIG. 7B, the communication device 10 can identify the profile to be used by the opposite device 2 by using Delay_req, which is the time synchronization signal that is first received from the opposite device 2, which is the Client.

[0054] 7C, the communication device 10 does not receive a time synchronization signal from the opposite device 2, which is the client. Therefore, the communication device 10 actively acquires the time synchronization signal from the opposite device 2, and can identify the profile used by the opposite device 2 using the acquired time synchronization signal.

[0055] 7A, the time synchronization signal is not transmitted from the counterpart device 1, which is the Master, unless the communication device 10 transmits a signaling. Therefore, the communication device 10 actively acquires the time synchronization signal from the counterpart device 1, and can identify the profile used by the counterpart device 1 using the acquired time synchronization signal.

[0056] When the communication device 10 is a client in FIG. 7C, the communication device 10 can identify the profile used by the counterpart device 1 by using the time synchronization signal Announce or Sync that is first received from the counterpart device 1 that is a master.

[0057] 8A and 8B are diagrams showing an example of the operation of a Master and a Client at the start of communication in PTP (P2P). Fig. 8A is a diagram showing an example of the operation of a Master and a Client when, after communication has started between the Master and the Client, the communication rate is adjusted in response to a request from the Client. Fig. 8B is a diagram showing an example of the operation of a Master and a Client when, after communication has started between the Master and the Client, communication continues at a preset communication rate.

[0058] As shown in Fig. 8A, the Master transmits an Announce and then a Sync. Although not shown in Fig. 8A for simplicity, upon receiving the Announce and Sync, the Client transmits a Pdelay_req to the Master. This initiates communication between the Master and the Client. After communication has started, if the Client transmits a request (Signaling (request)) to change the communication rate, the communication rate is changed in accordance with the request. On the other hand, if the communication rate is not changed, the Master repeatedly transmits an Announce and a Sync, and the Client repeatedly transmits a Pdelay_req, as shown in Fig. 8B.

[0059] When the communication device 10 is the Master in FIG. 8A, the communication device 10 can identify the profile to be used by the opposite device 2 by using a Signaling (request) that is a time synchronization signal that is first received from the opposite device 2 that is the Client.

[0060] When the communication device 10 is the Master in FIG. 8B, the communication device 10 can identify the profile to be used by the opposite device 2 using Pdelay_req, which is the time synchronization signal that is first received from the opposite device 2, which is the Client.

[0061] When the communication device 10 functions as a client in Figures 8A and 8B, the communication device 10 can identify the profile to be used by the counterpart device 1 using the time synchronization signal Announce or Sync that it receives first from the counterpart device 1, which is the master.

[0062] Below, the specific operation of identifying a profile by the identification unit 12 will be described for each case: whether the communication layer is L2 or L3, whether the target of profile identification is a higher-level device (opposing device 1) or a lower-level device (opposing device 2), and whether the communication device 10 passively or actively acquires a time synchronization signal used for profile identification. Passively acquiring a time synchronization signal means that the communication device 10 receives a time synchronization signal transmitted from the opposing devices 1 and 2 without any action from the communication device 10. Actively acquiring a time synchronization signal means that the communication device 10 transmits a time synchronization signal (first time synchronization signal) to the opposing devices 1 and 2, and receives a time synchronization signal (second time synchronization signal) transmitted from the opposing devices 1 and 2 in response to the time synchronization signal.

[0063] Also, hereinafter, for the sake of simplicity of description, a combination of a communication layer, an identification target of a profile, and a method of acquiring a time synchronization signal (passive or active) will be denoted as "communication layer / profile identification target / passive or active". For example, when the communication layer is L2, the identification target of the profile is a lower-level device, and the communication device 10 passively acquires the time synchronization signal used for profile identification, it is denoted as "L2 / lower-level device / passive".

[0064] <In the case of L2 / lower-level device / passive> FIG. 9A is a flowchart showing an example of the operation of the identification unit 12 in the case of L2 / lower-level device / passive. The profiles to be identified in FIG. 9A are D (unicast (unicast negotiation enable / disable) / multicast, E2E / P2P), T1, A, P.

[0065] The identification unit 12 performs settings necessary for communication with the lower-level device at L2 and connects to the lower-level device (opposing device 2) (step S101). In this embodiment, it is assumed that the communication device 10 already knows whether the communication device 10 and the opposing devices 1 and 2 communicate at L2 / L3.

[0066] The identification unit 12 determines whether it has received a time synchronization signal (for example, Signaling shown in FIG. 7A or Delay_req shown in FIG. 7B, but not limited thereto) from the lower-level device via the communication interface 11 (step S102). <><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><00><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><0><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><0><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><0><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><<>000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><00><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><000><​​​​​​​​​​If it is determined that the destination address of the time synchronization signal is not a multicast address (the destination address is a unicast address) (step S103: No), the identification unit 12 determines whether unicast negotiation is enabled (whether unicast negotiation is present) (step S104). Specifically, the identification unit 12 determines whether a time synchronization signal including a REQUESTUNICAST_TRASMISSION TLV has been received. If the identification unit 12 has received a time synchronization signal including a REQUESTUNICAST_TRASMISSION TLV, it determines that unicast negotiation is enabled. If the identification unit 12 has not received a time synchronization signal including a REQUESTUNICAST_TRASMISSION TLV, it determines that unicast negotiation is disabled.

[0070] If it is determined that unicast negotiation is enabled (step S104: Yes), the identification unit 12 determines whether the time synchronization method is P2P (step S105). Specifically, the identification unit 12 determines whether the message Type of the REQUESTUNICAST_TRASMISSION TLV included in the received time synchronization signal includes Pdelay_resp. If the identification unit 12 determines that the message Type of the REQUESTUNICAST_TRASMISSION TLV includes Pdelay_resp, it determines that the time synchronization method is P2P. Furthermore, if the identification unit 12 determines that the message Type of the REQUESTUNICAST_TRASMISSION TLV does not include Pdelay_resp (includes Delay_resp), it determines that the time synchronization method is E2E.

[0071] If it is determined that the time synchronization method is P2P (step S105: Yes), the identification unit 12 identifies that the profile used in the lower device is D (unicast, unicast negotiation enable, P2P) (step S106), and ends the process.

[0072] If it is determined that the time synchronization method is not P2P (it is E2E) (step S105: No), the identification unit 12 identifies that the profile to be used by the lower-level device is D (unicast, unicast negotiation enable, E2E) (step S107) and terminates the processing.

[0073] If it is determined that unicast negotiation is not enabled (step S104: No), the identification unit 12 determines whether the time synchronization method is P2P or not (step S108). Specifically, the identification unit 12 determines whether a Pdelay_request message has been received from a lower-level device. If the identification unit 12 determines that a Pdelay_request message has been received, it determines that the time synchronization method is P2P. If the identification unit 12 determines that a Pdelay_request message has not been received, it determines that the time synchronization method is E2E.

[0074] If it is determined that the time synchronization method is P2P (step S108: Yes), the identification unit 12 identifies that the profile used by the lower-level device is D (unicast, unicast negotiation disable, P2P) (step S109), and ends the process.

[0075] If it is determined that the time synchronization method is not P2P (it is E2E) (step S108: No), the identification unit 12 identifies that the profile to be used by the lower-level device is D (unicast, unicast negotiation disable, E2E) (step S110) and terminates the processing.

[0076] If it is determined that the destination address of the time synchronization signal is a multicast address (step S103: Yes), the identification unit 12 determines whether the time synchronization method is P2P or not (step S111). The identification unit 12 determines whether the time synchronization method is P2P or not by the same process as in step S108.

[0077] If it is determined that the time synchronization method is P2P (step S111: Yes), the identification unit 12 determines whether the profile used by the lower-level device is AS (step S112). Specifically, the identification unit 12 determines whether the time synchronization signal received from the lower-level device includes a Message interval request or a gPTP-capable TLV.

[0078] If it is determined that the time synchronization signal includes a Message interval request or a gPTP-capable TLV (step S112: Yes), the identification unit 12 identifies that the profile used by the lower-level device is AS (step S113) and terminates the processing.

[0079] If it is determined that the time synchronization signal does not include a Message interval request and a gPTP-capable TLV (step S112: No), the identification unit 12 identifies that the profile used by the lower-level device is D (multicast, P2P) (step S114) and terminates the processing.

[0080] If it is determined that the time synchronization method is not P2P (it is E2E) (step S111: No), the identification unit 12 determines whether the profile used by the lower device is T1 (step S115). Specifically, the identification unit 12 determines whether the time synchronization signal received from the lower device includes a Delay_request message and whether the reception interval is less than 1 second.

[0081] When it is determined that the time synchronization signal includes a Delay_request message and its reception interval is less than 1 second (step S115: Yes), the identification unit 12 identifies that the profile used by the lower-level device is T1 (step S116), and ends the process.

[0082] When it is determined that the time synchronization signal does not include a Delay_request message, or even if it includes a Delay_request message, its reception interval is 1 second or more (step S115: No), the identification unit 12 identifies that the profile used by the lower-level device is D (multicast, E2E) (step S117), and ends the process.

[0083] <In the case of L3 / lower-level device / passive> Figure 9B is a flowchart showing an example of the operation of the identification unit 12 in the case of L3 / lower-level device / passive. The profiles to be identified in Figure 9B are D (unicast (unicast negotiation enable / disable) / multicast, E2E / P2P), T2 (unicast, unicast negotiation enable, E2E), S (unicast (unicast negotiation disable) / multicast, E2E / P2P).

[0084] The identification unit 12 performs the settings necessary for communication with the lower-level device (opposing device 2) at L3 and connects to the lower-level device (step S201).

[0085] The identification unit 12 determines whether it has received a time synchronization signal (for example, Signaling shown in Figure 7A or Delay_req shown in Figure 7B, but not limited to these) from the lower-level device via the communication interface 11 (step S202).

[0086] When it is determined that the time synchronization signal has not been received from the lower-level device (step S202: No), the identification unit 12 proceeds to the process in the case of L3 / lower-level device / active, which will be described later.

[0087] If it is determined that a time synchronization signal has been received from a lower-level device (step S202: Yes), the identification unit 12 determines whether the destination address of the received time synchronization signal is a multicast address (step S203).

[0088] If it is determined that the destination address of the time synchronization signal is not a multicast address (the destination address is a unicast address) (step S203: No), the identification unit 12 determines whether unicast negotiation is enabled (whether unicast negotiation is present) (step S204). The identification unit 12 determines whether unicast negotiation is enabled, for example, by the same process as in step S104.

[0089] If it is determined that unicast negotiation is enabled (step S204: Yes), the identification unit 12 determines whether the time synchronization method is P2P or not (step 205). The identification unit 12 determines whether the time synchronization method is P2P or not by, for example, the same process as in step S105.

[0090] If it is determined that the time synchronization method is P2P (step S205: Yes), the identification unit 12 identifies that the profile used by the lower-level device is D or S (unicast, unicast negotiation enable, P2P) (step S206), and ends the process.

[0091] If it is determined that the time synchronization method is not P2P (it is E2E) (step S205: No), the identification unit 12 identifies that the profile used by the lower-level device is D, S (unicast, unicast negotiation enable, E2E) or T2 (step S207), and terminates the processing.

[0092] If it is determined that unicast negotiation is not enabled (step S204: No), the identification unit 12 determines whether the time synchronization method is P2P (step S208). The identification unit 12 determines whether the time synchronization method is P2P by the same process as in step S108.

[0093] If it is determined that the time synchronization method is P2P (step S208: Yes), the identification unit 12 identifies that the profile used by the lower-level device is D (unicast, unicast negotiation disable, P2P) (step S209), and ends the process.

[0094] If it is determined that the time synchronization method is not P2P (it is E2E) (step S208: No), the identification unit 12 identifies that the profile used by the lower-level device is D (unicast, unicast negotiation disable, E2E) (step S210) and terminates the processing.

[0095] If it is determined that the destination address of the time synchronization signal is a multicast address (step S203: Yes), the identification unit 12 determines whether the method of time synchronization by PTP is P2P (step S211). The identification unit 12 determines whether the method of time synchronization is P2P by the same process as in step S208.

[0096] If it is determined that the time synchronization method is not P2P (it is E2E) (step S211: No), the identification unit 12 identifies that the profile used by the lower-level device is D or S (multicast, E2E) (step S212) and terminates the processing.

[0097] If it is determined that the time synchronization method is P2P (step S211: Yes), the identification unit 12 identifies that the profile used by the lower-level device is D or S (multicast, P2P) (step S213), and ends the process.

[0098] In FIG. 9B, in steps S206, S212, and S213, it is impossible to identify whether the profile used by the lower device is D or S. Also, in FIG. 9B, in step S207, it is impossible to identify whether the profile used by the lower device is D, S, or T2. However, by combining the method of identifying whether the profile used by the lower device is S when the communication device 10 actively acquires the time synchronization signal, which will be described later, the identification unit 12 can identify whether the profile used by the lower device is S.

[0099] <L2 / Upper device / Passive case> FIG. 9C is a flowchart showing an example of the operation of the identification unit 12 in the case of L2 / upper device / passive. The profiles to be identified in FIG. 9C are D (unicast (unicast negotiation enable / disable) / multicast, E2E / P2P), T1 (multicast, E2E), A (multicast, E2E), and P (multicast, E2E).

[0100] The identification unit 12 performs the settings necessary for communication with the upper device (opposing device 1) at L2 and connects to the upper device (step S301).

[0101] The identification unit 12 determines whether it has received a time synchronization signal from the upper device via the communication interface 11 (step S302).

[0102] If it is determined that the time synchronization signal has not been received from the upper device (step S302: No), the identification unit 12 proceeds to the processing in the case of L2 / upper device / active, which will be described later.

[0103] If it is determined that the time synchronization signal has been received from the upper device (step S302: Yes), the identification unit 12 determines whether the destination address of the received time synchronization signal is a unicast address and whether unicast negotiation is enabled (step S303).

[0104] If it is determined that the destination address of the time synchronization signal is a unicast address and that unicast negotiation is enabled (step S303: Yes), the identification unit 12 identifies that the profile used by the upper device is D (unicast, unicast negotiation enable, P2P) or D (unicast, unicast negotiation enable, E2E) (step S304), and terminates the processing.

[0105] If it is determined that the destination address of the time synchronization signal is a multicast address, or that the destination address of the time synchronization signal is a unicast address but unicast negotiation is disabled (step S303: No), the identification unit 12 determines whether the destination address of the time synchronization signal is a multicast address (step S305).

[0106] If it is determined that the destination address is not a multicast address (step S305: No), the identification unit 12 identifies that the profile used by the upper device is D (unicast, unicast negotiation disable, P2P) or D (unicast, unicast negotiation disable, E2E) (step S306), and terminates the processing.

[0107] If it is determined that the destination address is a multicast address (step S305: Yes), the identification unit 12 determines whether the profile used by the upper device is P (step S307). Specifically, the identification unit 12 determines whether the Announce transmitted from the upper device includes an IEEE_C37_238 TLV.

[0108] When it is determined that the Announce includes the IEEE_C37_238 TLV (step S307: Yes), the identification unit 12 identifies that the profile used by the upper device is P (step S308), and ends the process.

[0109] When it is determined that the Announce does not include the IEEE_C37_238 TLV (step S307: No), the identification unit 12 determines whether the profile used by the upper device is AS (step S309). Specifically, the identification unit 12 determines whether it receives a follow_up message including the Follow_Up information TLV with the organizationId of 00-80-C2 from the upper device. The follow_up message is a time synchronization signal transmitted from the upper device when complementing information that cannot be completely transmitted by Sync in AS.

[0110] When it is determined that it has received a follow_up message including the Follow_Up information TLV with the organizationId of 00-80-C2 (step S309: Yes), the identification unit 12 identifies that the profile used by the upper device is AS (step S310), and ends the process.

[0111] When it is determined that it has not received a follow_up message including the Follow_Up information TLV with the organizationId of 00-80-C2 (step S309: No), the identification unit 12 identifies that the profile used by the upper device is D (multicast, P2P), D (multicast, E2E), or T1 (step S311), and ends the process.

[0112] <In the case of the upper device being passive> 9D is a flowchart showing an example of the operation of the identification unit 12 in the case of L3 / higher-level device / passive. The profiles to be identified in FIG. 9D are D (unicast (unicast negotiation enable / disable) / multicast, E2E / P2P), T2 (unicast, unicast negotiation enable, E2E), and S (unicast, (unicast negotiation disable) / multicast, E2E / P2P).

[0113] The identification unit 12 performs settings required for communication with a higher-level device (opposing device 1) at L3, and connects to the higher-level device (step S401).

[0114] The identification unit 12 determines whether or not a time synchronization signal has been received from a higher-level device via the communication interface 11 (step S402).

[0115] If it is determined that the time synchronization signal has not been received from the higher-level device (step S402: No), the identification unit 12 proceeds to processing for the L3 / higher-level device / active case, which will be described later.

[0116] If it is determined that a time synchronization signal has been received from a higher-level device (step S402: Yes), the identification unit 12 determines whether the destination address of the received time synchronization signal is a unicast address and whether unicast negotiation is enabled (step S403).

[0117] If it is determined that the destination address of the time synchronization signal is a unicast address and that unicast negotiation is enabled (step S403: Yes), the identification unit 12 identifies that the profile to be used by the upper device is D (unicast, unicast negotiation enable, P2P), D (unicast, unicast negotiation enable, E2E), or T2 (step S404), and terminates the processing.

[0118] If it is determined that the destination address of the time synchronization signal is a multicast address, or that the destination address of the time synchronization signal is a unicast address but unicast negotiation is disabled (step S403: No), the identification unit 12 determines whether the destination address of the time synchronization signal is a multicast address (step S405).

[0119] If it is determined that the destination address is a multicast address (step S405: Yes), the identification unit 12 determines whether the profile used by the upper device is S (step S406). Specifically, the identification unit 12 determines whether a management message including a Synchronization Metadata TLV has been received from the upper device. In SMPTE, the management message is transmitted from the upper device to transmit profile-specific information separately from an Announce.

[0120] If it is determined that a management message including a Synchronization Metadata TLV has not been received (step S406: No), the identification unit 12 identifies that the profile used by the upper device is D (multicast, P2P) or D (multicast, E2E) (step S407), and terminates the processing.

[0121] If it is determined that a management message including a Synchronization Metadata TLV has been received (step S406: Yes), the identification unit 12 identifies that the profile used by the upper device is S (multicast, P2P) or S (multicast, E2E) (step S408), and terminates the processing.

[0122] When it is determined that the destination address is not a multicast address (step S405: No), the identification unit 12 determines whether the profile used by the upper device is S (step S409). The identification unit 12 determines whether the profile used by the upper device is S by the same process as in step S406.

[0123] When it is determined that a management message including a Synchronization Metadata TLV has not been received (step S409: No), the identification unit 12 identifies that the profile used by the upper device is D (unicast, unicast negotiation disable, P2P) or D (unicast, unicast negotiation disable, E2E) (step S410), and ends the process.

[0124] When it is determined that a management message including a Synchronization Metadata TLV has been received (step S406: Yes), the identification unit 12 identifies that the profile used by the upper device is S (unicast, unicast negotiation disable, P2P) or S (unicast, unicast negotiation disable, EEE) (step S411), and ends the process.

[0125] <In the case of L2 / lower device / active> FIG. 10A is a flowchart showing an example of the operation of the identification unit 12 in the case of L2 / lower device / active. The profiles to be identified in FIG. 10A are D (unicast (unicast negotiation disable) / multicast, E2E), T1 (multicast, E2E). <H

[0126] The identification unit 12 performs settings necessary for communication with the lower device (opposing device 2) at L2 and connects to the lower device (step S501).

[0127] [[ID=()]] The identification unit 12 determines whether or not a time synchronization signal has been received from a lower-level device via the communication interface 11 (step S502).

[0128] If it is determined that a time synchronization signal has been received from the lower device (step S502: Yes), the identification unit 12 proceeds to the processing for the L2 / lower device / passive case described with reference to FIG. 9A.

[0129] If it is determined that a time synchronization signal has not been received from the lower device (step S502: No), the identification unit 12 determines whether the profile used by the lower device is T1 (step S503). Specifically, the identification unit 12 causes the time synchronizer 13 to transmit Announce and Sync messages (first time synchronization signals) to a multicast address at transmission intervals of less than one second, and in response, determines whether a Delay_req message has been received from the lower device.

[0130] If it is determined that a Delay_req message has been received from the lower device (step S503: Yes), the identifying unit 12 determines that the profile used by the lower device is T1 (step S504), and ends the process.

[0131] If it is determined that a Delay_req message has not been received from the lower device (step S503: No), the identification unit 12 determines whether the profile used by the lower device is D (multicast) (step S505). Specifically, the identification unit 12 causes the time synchronization unit 13 to transmit Announce and Sync messages (first time synchronization signals) to a multicast address at transmission intervals of less than one second, and in response thereto, determines whether a Delay_req message has been received from the lower device.

[0132] When it is determined that a Delay_req message has been received from the lower device (step S505: Yes), the identification unit 12 identifies that the profile used by the lower device is D (multicast, E2E) (step S506), and ends the process.

[0133] When it is determined that a Delay_req message has not been received from the lower device (step S505: No), the identification unit 12 identifies that the profile used by the lower device is D (unicast, unicast negotiation disable, E2E) (step S507), and ends the process.

[0134] <When the lower device is active in L3> Figure 10B is a flowchart showing an example of the operation of the identification unit 12 when the lower device is active in L3. The profiles to be identified in Figure 10B are D (unicast (unicast negotiation disable) / multicast, E2E), S (unicast (unicast negotiation disable) / multicast, E2E).

[0135] The identification unit 12 performs the settings necessary for communication with the lower device (opposing device 2) in L3 and connects to the lower device (step S601).

[0136] The identification unit 12 determines whether a time synchronization signal has been received from the lower device via the communication interface 11 (step S602).

[0137] When it is determined that a time synchronization signal has been received from the lower device (step S602: Yes), the identification unit 12 proceeds to the process for the case where the lower device is passive in L3, which was described with reference to Figure 9B.

[0138] If it is determined that a time synchronization signal has not been received from the lower device (step S602: No), the identification unit 12 determines whether the profile used by the lower device is S (multicast) (step S603). Specifically, the identification unit 12 causes the time synchronization unit 13 to transmit a Management message requesting parameter setting to a multicast address, and determines whether the setting request has been accepted. More specifically, the identification unit 12 causes the time synchronization unit 13 to transmit a Management message (first time synchronization signal) whose action field is COMMAND and whose TLV is Synchronization Metadata TLV to the multicast address. Then, the identification unit 12 determines whether a Management message whose action field is ACKNOWLEDGE and whose TLV is Synchronization Metadata TLV has been received from the lower device.

[0139] If it is determined that a Management message whose actionField is ACKNOWLEDGE and whose TLV is Synchronization Metadata TLV has been received from a lower-level device (step S603: Yes), the identification unit 12 identifies that the profile used by the lower-level device is S (multicast, E2E) (step S604) and terminates the processing.

[0140] When it is determined that a Management message whose action field is ACKNOWLEDGE and whose TLV is Synchronization Metadata TLV has not been received from the lower device (step S603: No), the identification unit 12 determines whether the profile used by the lower device is S (unicast) (step S605). Specifically, the identification unit 12 causes the time synchronization unit 13 to transmit a Management message requesting parameter setting to a unicast address, and determines whether the setting request has been accepted. More specifically, the identification unit 12 causes the time synchronization unit 13 to transmit a Management message (first time synchronization signal) whose action field is COMMAND and whose TLV is Synchronization Metadata TLV to the lower device (opposite device 2). Then, the identification unit 12 determines whether a Management message (second time synchronization signal) whose action field is ACKNOWLEDGE and whose TLV is Synchronization Metadata TLV has been received from the lower device.

[0141] If it is determined that a Management message whose actionField is ACKNOWLEDGE and whose TLV is Synchronization Metadata TLV has been received from a lower-level device (step S605: Yes), the identification unit 12 identifies that the profile used by the lower-level device is S (unicast, unicast negotiation disable, E2E) (step S606) and terminates the processing.

[0142] When it is determined that a Management message in which the actionField is ACKNOWLEDGE and the TLV is a Synchronization Metadata TLV has not been received from the lower device (step S605: No), the identification unit 12 determines whether the profile used by the lower device is D (multicast) (step S607). Specifically, the identification unit 12 causes the time synchronization unit 13 to transmit Announce and Sync (the first time synchronization signal) to a unicast address, and determines whether a Delay_req (the second time synchronization signal) is received in response thereto.

[0143] When it is determined that Delay_req has been received (step S607: Yes), the identification unit 12 identifies that the profile used by the lower device is D (multicast, E2E) (step S608), and ends the process.

[0144] When it is determined that Delay_req has not been received (step S607: No), the identification unit 12 identifies that the profile used by the lower device is D (unicast, unicast negotiation disable, E2E) (step S609), and ends the process.

[0145] <When the upper device in L2 is active> Figure 10C is a flowchart showing an example of the operation of the identification unit 12 when the upper device in L2 is active. The profile to be identified in Figure 10C is D (unicast, unicast negotiation enable, E2E).

[0146] The identification unit 12 performs settings necessary for communication with the upper device (opposing device 1) in L2 and connects to the upper device (step S701).

[0147] The identification unit 12 determines whether a time synchronization signal has been received from the upper device via the communication interface 11 (step S702).

[0148] When it is determined that a time synchronization signal has been received from the host device (step S702: Yes), the identification unit 12 proceeds to the process in the case of L2 / host device / passive, which was described with reference to FIG. 9C.

[0149] When it is determined that a time synchronization signal has not been received from the host device (step S702: No), the identification unit 12 determines that the profile used in the host device is D (unicast, unicast negotiation enable, E2E) (step S703), and ends the process.

[0150] <In the case of L3 / host device / active> FIG. 10D is a flowchart showing an example of the operation of the identification unit 12 in the case of L3 / host device / active. The profiles to be identified in FIG. 10D are D (unicast, unicast negotiation enable, E2E) and T2 (unicast, unicast negotiation enable, E2E).

[0151] The identification unit 12 performs settings necessary for communication with the host device at L3 and connects to the host device (step S801).

[0152] The identification unit 12 determines whether a time synchronization signal has been received from the host device via the communication interface 11 (step S802).

[0153] When it is determined that a time synchronization signal has been received from the host device (step S802: Yes), the identification unit 12 proceeds to the process in the case of L3 / host device / passive, which was described with reference to FIG. 9D.

[0154] When it is determined that a time synchronization signal has not been received from the host device (step S803: No), the identification unit 12 determines that the profile used in the host device is D (unicast, unicast negotiation enable, E2E) or T2 (step S803), and ends the process.

[0155] 9A to 10D, the communication device 10 has been described separately as a case where it passively acquires the time synchronization signal from the counterpart devices 1 and 2 (receiving the time synchronization signal transmitted from the counterpart devices 1 and 2 without any action from the communication device 10) and a case where it actively acquires the time synchronization signal from the counterpart devices 1 and 2 (transmitting a time synchronization signal (first time synchronization signal) from the communication device 10 and receiving a time synchronization signal (second time synchronization signal) transmitted from the counterpart devices 1 and 2 in response to that time synchronization signal), but the present invention is not limited to this.

[0156] The communication device 10 may combine passive acquisition of time synchronization signals with active acquisition of time synchronization signals. For example, if the communication device 10 does not receive a time synchronization signal for a predetermined period of time or longer due to some reason, the communication device 10 may switch from passive acquisition of time synchronization signals to active acquisition of time synchronization signals. That is, if the communication device 10 does not receive a time synchronization signal from the counterpart devices 1 and 2 when passively acquiring a time synchronization signal, the communication device 10 may transmit a time synchronization signal (first time synchronization signal) to the counterpart devices 1 and 2, receive a time synchronization signal (second time synchronization signal) transmitted from the counterpart devices 1 and 2 in response to the time synchronization signal, and identify the profile used by the counterpart devices 1 and 2 based on information included in the received time synchronization signal.

[0157] As described above, the communication device 10 according to this embodiment includes an identification unit 12 and a determination unit 14. The identification unit 12 continuously identifies the profile used by the opposite devices 1 and 2 based on information regarding the transmission and reception of the time synchronization signal and the time synchronization method according to one of multiple profiles, which information is included in the time synchronization signal acquired from the opposite devices 1 and 2. The determination unit 14 determines whether or not the profile used by the opposite devices 1 and 2 has changed, based on the past profile of the opposite devices 1 and 2 identified by the identification unit 12 and the current profile of the opposite devices 1 and 2 identified by the identification unit 12.

[0158] Information regarding the transmission and reception of time synchronization signals according to a single profile and the method of time synchronization is information that is always included in the time synchronization signals transmitted and received for time synchronization between the communication device 10 and the counterpart devices 1 and 2. By using such information, the communication device 10 according to this embodiment can identify the profiles used by the counterpart devices 1 and 2 regardless of the implementation of the device. Furthermore, by continuously identifying the profiles used by the counterpart devices 1 and 2, it is possible to detect changes in the profiles used by the counterpart devices 1 and 2 based on past profiles and current profiles.

[0159] (Second embodiment) Fig. 11 is a diagram showing a configuration example of a communication device 10a according to the second embodiment of the present disclosure. In Fig. 11, the same components as those in Fig. 3 are denoted by the same reference numerals, and description thereof will be omitted.

[0160] 11, a communication device 10a according to this embodiment includes a communication interface 11, an identification unit 12, a time synchronization unit 13, a determination unit 14, and a notification unit 15. The communication device 10a shown in FIG. 11 differs from the communication device 10 shown in FIG. 3 in that the notification unit 15 is added.

[0161] The notification unit 15 receives the determination result by the determination unit 14 as to whether or not the profiles used by the opposed devices 1 and 2 have changed. When the determination unit 14 determines that the profiles used by the opposed devices 1 and 2 have changed, the notification unit 15 notifies the outside that the profiles used by the opposed devices 1 and 2 have changed. The notification unit 15 notifies, for example, the operating system 3 that manages the communication device 10a of the change in the profiles used by the opposed devices 1 and 2. The notification unit 15 may also notify, for example, the change in the profiles used by the opposed devices 1 and 2 by displaying on a display device included in the communication device 10a or a display device connected to the communication device 10a via a wired or wireless connection. The notification unit 15 may also notify, for example, the change in the profiles used by the opposed devices 1 and 2 by audio output.

[0162] According to the communication device 10a of this embodiment, it is possible to notify the outside of the occurrence of a change in the profile used by the associated devices 1 and 2.

[0163] (Third embodiment) Fig. 12 is a diagram showing an example of the configuration of a communication device 10b according to the third embodiment of the present disclosure. In Fig. 12, the same components as those in Fig. 3 are denoted by the same reference numerals, and the description thereof will be omitted.

[0164] 12, the communication device 10b according to this embodiment includes a communication interface 11, an identification unit 12b, a time synchronization unit 13, and a setting storage unit 16. The communication device 10b according to this embodiment differs from the communication device 10 according to the first embodiment in that the setting storage unit 16 is added and the identification unit 12 is changed to an identification unit 12b.

[0165] The setting storage unit 16 stores, for each of a plurality of profiles that are candidates for use when the communication device 10b and the counterpart devices 1 and 2 perform time synchronization, settings required for the time synchronization unit 13 for the communication device 10b and the counterpart devices 1 and 2 to perform time synchronization. The settings for the time synchronization unit 13 include, for example, a message transmission cycle, a domain number, and a priority.

[0166] The identification unit 12b identifies the profile to be used by the opposite devices 1 and 2 in the same manner as the identification unit 12. The identification unit 12b reads out the settings corresponding to the identified profile from the setting storage unit 16 and sets them in the time synchronization unit 13. In this way, the identification unit 12b sets the communication device 10b (time synchronization unit 13) to a setting according to the profile identified to be used by the opposite devices 1 and 2. Note that, if unicast message negotiation is enabled in the profile used by the opposite devices 1 and 2, the opposite devices 1 and 2 propose a message transmission period (a time synchronization signal including the message transmission period is transmitted). Therefore, if unicast message negotiation is enabled in the profile used by the opposite devices 1 and 2, the identification unit 12b may read the message transmission period included in the time synchronization signal and set the message transmission period in the time synchronization unit 13 based on the read value.

[0167] This allows settings to be made automatically according to the identified profile, which reduces the workload involved in identifying the profile to be used and making settings corresponding to the identified profile when installing or replacing equipment, for example.

[0168] 12, an example has been described in which the communication device 10b includes a setting storage unit 16 that stores settings necessary for the communication device 10b and the associated devices 1 and 2 to perform time synchronization, but the present invention is not limited to this. The settings necessary for the time synchronization unit 13 may be stored in an external memory connectable to the communication device 10b. Furthermore, the settings necessary for the time synchronization unit 13 may be stored in an external device such as a server device connected to the communication device 10b via a network.

[0169] Next, the hardware configuration of the communication devices 10 and 10a according to the present disclosure will be described.

[0170] 13 is a diagram illustrating an example of a hardware configuration of a communication device 10, 10a, or 10b according to the present disclosure. In FIG. 13, an example of the hardware configuration of the communication device 10, 10a, or 10b is illustrated, where the communication device 10, 10a, or 10b is configured by a computer capable of executing program instructions. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a personal computer (PC), an electronic notepad, or the like. The program instructions may be program code, code segments, or the like for performing necessary tasks.

[0171] 13, the communication devices 10, 10a, and 10b each include a processor 21, a read-only memory (ROM) 22, a random access memory (RAM) 23, a storage 24, an input unit 25, a display unit 26, and a communication interface (I / F) 27. Each component is connected to each other via a bus 29 so as to be able to communicate with each other. The processor 21 is specifically a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), a digital signal processor (DSP), a system on a chip (SoC), or the like, and may be configured by a plurality of processors of the same type or different types.

[0172] The processor 21 is a control unit that controls each component and performs various arithmetic operations. That is, the processor 21 reads a program from the ROM 22 or the storage 24 and executes the program using the RAM 23 as a work area. The processor 21 controls each component and performs various arithmetic operations in accordance with the program stored in the ROM 22 or the storage 24. In this embodiment, the ROM 22 or the storage 24 stores a program for causing a computer to operate as the communication device 10, 10a according to the present disclosure. The program is read and executed by the processor 21, thereby realizing each component of the communication device 10, 10a, 10b described above.

[0173] The program may be provided in a form stored on a non-transitory storage medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), a USB (Universal Serial Bus) memory, etc. The program may also be provided in a form downloaded from an external device via a network.

[0174] The ROM 22 stores various programs and various data. The RAM 23 temporarily stores programs or data as a working area. The storage 24 is configured with an HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs including the operating system and various data.

[0175] The input unit 25 includes a pointing device such as a mouse and a keyboard, and is used to input various types of information.

[0176] The display unit 26 is, for example, a liquid crystal display, and displays various information. The display unit 26 may function as the input unit 25 by adopting a touch panel system.

[0177] The communication interface 27 is an interface for communicating with other devices (for example, the opposing devices 1 and 2).

[0178] A computer can be suitably used to function as each of the above-described communication devices 10, 10a, and 10b. Such a computer can be realized by storing a program describing the processing content for realizing the functions of each of the communication devices 10, 10a, and 10b in a memory unit of the computer and having the processor of the computer read and execute the program. In other words, the program can cause the computer to function as the above-described communication devices 10, 10a, and 10b. The program can also be recorded on a non-transitory storage medium. The program can also be provided via a network.

[0179] The following additional notes are provided regarding the above-described embodiments.

[0180] [Additional note 1] A communication device that performs time synchronization with an opposing communication device by transmitting and receiving a time synchronization signal according to one of a plurality of profiles, Memory and a control unit connected to the memory; Equipped with the control unit continuously identifies a profile to be used by the opposite device based on information regarding a method of transmitting and receiving a time synchronization signal according to one of the plurality of profiles and the time synchronization method, the information being included in the time synchronization signal acquired from the opposite device; The communication device determines whether or not there is a change in the profile used by the opposing device based on the identified past profile and the identified current profile.

[0181] [Additional note 2] In the communication device according to claim 1, The control unit transmits a first time synchronization signal to the opposing device, receives a second time synchronization signal transmitted from the opposing device in response to the first time synchronization signal, and identifies a profile to be used by the opposing device based on information contained in the received second time synchronization signal.

[0182] [Additional note 3] In the communication device according to claim 1, When the control unit determines that a profile used by the opposing device has changed, the control unit notifies an external device of the change in the profile used by the opposing device.

[0183] [Additional note 4] In the communication device according to claim 1, When the control unit determines that a profile used by the opposing device has changed, the control unit performs settings on the communication device according to the current profile.

[0184] [Additional note 5] A communication method for a communication device that performs time synchronization with a counterpart device by transmitting and receiving a time synchronization signal according to one of a plurality of profiles, the method comprising: acquiring the time synchronization signal from the opposite device; continuously identifying a profile to be used by the opposing device based on information regarding transmission and reception of a time synchronization signal according to one of the plurality of profiles and a method of the time synchronization, which is included in the acquired time synchronization signal; A communication method, comprising determining whether or not there is a change in the profile used by the opposing device based on the identified past profile and the identified current profile.

[0185] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be interpreted as being limited by the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the claims. For example, multiple building blocks shown in the block diagrams of the embodiments can be combined into one, or one building block can be divided. [Explanation of symbols]

[0186] 1,2 Opposite device 10,10a,10b Communication equipment 11 Communication Interface 12 Identification unit 13 Time synchronization unit 14 Judgment section 15 Notification Department 16 Setting memory section 21 processors 22 ROM 23 RAM 24 Storage 25 Input section 26 Display section 27 Communication I / F 29 Bus

Claims

1. A communication device that performs time synchronization with an opposing communication device by transmitting and receiving a time synchronization signal according to one of a plurality of profiles, an identification unit that continuously identifies a profile used by the opposite device based on information regarding transmission and reception of a time synchronization signal corresponding to one of the multiple profiles and a method of the time synchronization, which information is always included in the time synchronization signal acquired from the opposite device; A communication device comprising: a determination unit that determines whether or not there is a change in the profile used by the opposing device based on the past profile identified by the identification unit and the current profile identified by the identification unit.

2. 2. The communication device according to claim 1, A communication device in which the identification unit transmits a first time synchronization signal to the opposing device, receives a second time synchronization signal transmitted from the opposing device in response to the first time synchronization signal, and identifies a profile to be used by the opposing device based on information contained in the received second time synchronization signal.

3. 2. The communication device according to claim 1, The communication device further comprises a notification unit that, when the determination unit determines that a profile used by the opposing device has changed, notifies an external device of the occurrence of a change in the profile used by the opposing device.

4. 2. The communication device according to claim 1, The identification unit, when it is determined by the determination unit that a profile used by the opposing device has changed, performs settings on the communication device according to the current profile.

5. A communication method for a communication device that performs time synchronization with a counterpart device by transmitting and receiving a time synchronization signal according to one of a plurality of profiles, the method comprising: acquiring the time synchronization signal from the opposite device; continuously identifying a profile to be used by the opposing device based on information regarding transmission and reception of a time synchronization signal according to one of the plurality of profiles, which information is always included in the acquired time synchronization signal, and a method of the time synchronization; and determining whether or not there has been a change in the profile used by the opposing device based on the identified past profile and the identified current profile.

6. In the communication device according to claim 1, The information includes information indicating whether a destination address of the time synchronization signal is a unicast address or a multicast address, information indicating whether a communication rate between the opposite device and the communication device is adjusted when the destination address is a unicast address, and information indicating a method of the time synchronization; A communication device in which the identification unit identifies the profile to be used by the opposing device based on a combination of information indicating whether the destination address of the time synchronization signal is a unicast address or a multicast address, information indicating whether to adjust the communication rate between the opposing device and the communication device when the destination address is a unicast address, and information indicating the time synchronization method.

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