Communication device, communication system, and communication method

Abstract

A communication device (100) comprises: an E2E / P2P determination unit (103) serving as a profile determination unit that, on the basis of information which indicates a packet type and which is contained in a packet received from one of a Grand Master Clock (1) and a Client device (2) or from yet another communication device (100), determines a use profile from among a plurality of profiles for which methods for measuring transmission delay differ from one another; a packet processing determination unit (106) that determines packet processing to be performed on one of the devices and the other communication device (100) according to the determination result of the use profile; and packet transmission / reception units (101, 102) that transmit and receive packets according to the determined packet processing.

Description

COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

[0001] The present disclosure relates to a communication device, a communication system, and a communication method.

[0002] The Precision Time Protocol (PTP) defined in the IEEE-1588 standard is a protocol for synchronizing the time (device internal time) of computers on a LAN (Local Area Network) with high precision (see Non-Patent Document 1). PTP is used in a variety of fields, including mobile and industrial applications (see Non-Patent Documents 2 and 3). Figures 7A and 7B are diagrams showing an example configuration of a time synchronization system 10A that uses PTP to synchronize the time of devices on a network.

[0003] As shown in FIGS. 7A and 7B, a time synchronization system 10A includes a Grand Master Clock 1 and a Client device 2.

[0004] The Grand Master Clock 1 includes a GNSS antenna 1a that receives signals (GNSS signals) from satellites of a Global Navigation Satellite System (GNSS) such as the Global Positioning System (GPS). The Grand Master Clock 1 receives the GNSS signals via the GNSS antenna 1a and acquires International Atomic Time (TAI) from the received GNSS signals. The Grand Master Clock 1 has a master function that distributes the acquired TAI as a reference time via a network.

[0005] The client device 2 has a slave function for synchronizing the internal time of the device with the time of a device having a master function. The client device 2 is a device used by a user, such as a base station device in a mobile phone network.

[0006] When synchronizing the Grand Master Clock 1 with the client devices 2, a relay device for relaying signals may be provided between the Grand Master Clock 1 and the client devices 2 depending on the distance between the Grand Master Clock 1 and the client devices 2 and the number of client devices 2 synchronized with the Grand Master Clock 1. Examples of relay devices used in PTP include the Boundary Clock 3 shown in Fig. 7A and the Transparent Clock 4 shown in Fig. 7B.

[0007] The Boundary Clock 3 shown in FIG. 7A functions as a device with slave functionality with respect to a higher-level device with master functionality, and as a device with master functionality with respect to a lower-level device with slave functionality. In the time synchronization system 10A shown in FIG. 7A, the Boundary Clock 3 functions as a device with slave functionality with respect to the Grand Master Clock 1, and as a device with master functionality with respect to the Client device 2. Specifically, the Boundary Clock 3 measures an offset, which is the difference between the internal time of the Grand Master Clock 1 and the internal time of its own device (the difference between the internal time of the device with master functionality and the internal time of the device with slave functionality), by transmitting and receiving PTP packets with the Grand Master Clock 1, and synchronizes the internal time of its own device with the time of the Grand Master Clock 1 (reference time) based on the measured offset. Furthermore, the Boundary Clock 3 synchronizes the internal time of the Client device 2 with the internal time of its own device by transmitting and receiving PTP packets with the Client device 2.

[0008] 7B forwards PTP packets received from Grand Master Clock 1 to Client device 2, and forwards PTP packets received from Client device 2 to Grand Master Clock 1. Transparent Clock 4 measures the time it takes for a PTP packet to pass through its own device, and writes the result into the PTP packet while forwarding it. In this way, the internal time of Client device 2 can be synchronized with the internal time of Grand Master Clock 1.

[0009] IEEE Std 1588-2019, IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control SystemsITU-T G.8275.1 / Y.1369.1, Precision time protocol telecom profile for phase / time synchronization with full timing support from the networkIEEE Std 802.1AS‐2020, IEEE Standard for Local and Metropolitan Area Networks -- Timing and Synchronization for Time-Sensitive Applications

[0010] In PTP, different formats called profiles are defined for each field of use, which have different required parameters and time information formats, and time synchronization cannot be achieved between different profiles.One of the reasons why time synchronization cannot be achieved between different profiles is the difference in the method of measuring transmission delay.

[0011] There are two methods for measuring delay in a time synchronization system 10A including a transparent clock 4 shown in Fig. 7B: an end-to-end (E2E) method and a peer-to-peer (P2P) method. Each method will be described below.

[0012] Fig. 8 is a sequence diagram showing an example of the operation of each device in the E2E method. In Fig. 8, the Master device is a device equipped with a Master function, and the Client device is a device equipped with a Client function. There are two PTP time distribution methods: a two-step method and a one-step method. Fig. 8 explains the case where the two-step method is used.

[0013] At time T1, the Master device transmits a Sync message to Transparent Clock 4. Messages transmitted and received between devices in PTP include a field called a correction field (CF), which contains a correction value used for time correction in the Client device (for example, a value obtained by adding the time it takes for a frame to pass through the device). The Master device sets CF in the Sync message to 0. In the following, unless otherwise specified, the value of CF is assumed to be 0.

[0014] When the Transparent Clock 4 receives a Sync message at time dt1, it transmits the received Sync message to the Client device at time dt2. The Transparent Clock 4 stores the reception time dt1 of the Sync message from the Master device and the transmission time dt2 of the Sync message to the Client device.

[0015] At time T2, the client device receives the Sync message sent from Transparent Clock 4. The client device stores the time T2 when the Sync message was received.

[0016] After transmitting the Sync message, the Master device transmits a Follow_Up message to Transparent Clock 4. The Master device includes the transmission time T1 of the Sync message in the Follow_Up message.

[0017] When the Transparent Clock 4 receives the Follow_Up message, it transmits the received Follow_Up message to the Client device. The Transparent Clock 4 sets the CF of the Follow_Up message to the processing time of the Sync message in the Transparent Clock 4 (=dt2-dt1).

[0018] At time T3, the client device transmits a Delay_Req message to Transparent Clock 4. The client device periodically transmits the Delay_Req message.

[0019] When the Transparent Clock 4 receives the Delay_Req message at time dt3, it transmits the received Delay_Req message to the Master device at time dt4. The Transparent Clock 4 stores the reception time dt3 of the Delay_Req message from the Client device and the transmission time dt4 of the Delay_Req message to the Master device.

[0020] The master device receives the Delay_Req message at time T4 and stores the time T4 at which the master device received the Delay_Req message.

[0021] When the Master device receives the Delay_Req message, it transmits a Delay_Resp message to Transparent Clock 4. The Master device includes the reception time T4 of the Delay_Req message in the Delay_Resp message.

[0022] When the Transparent Clock 4 receives the Delay_Resp message, it transmits the received Delay_Resp message to the Client device. The Transparent Clock 4 sets the processing time of the Delay_Req message in the Transparent Clock 4 (=dt4-dt3) in the CF of the Delay_Resp message.

[0023] The client device calculates the offset, which is the difference between the device time of the master device and the device time of the client device, using the following formula (1): Offset = ((T2 - T1 - (dt2 - dt1)) - (T4 - T3 - (dt4 - dt3))) / 2 Formula (1) Based on the following: Time T1 when the master device sent the Sync message; Time T2 when the client device received the Sync message; Time T3 when the client device sent the Delay_Req message; Time T4 when the master device received the Delay_Resp message; the processing time of the Sync message in Transparent Clock 4 set in the CF of the Follow_Up message (= dt2 - dt1); and the processing time of the Delay_Req message in Transparent Clock 4 set in the CF of the Delay_Resp message (= dt4 - dt3).

[0024] The client device can synchronize its internal time with the internal time of the master device by correcting the internal time based on the calculated offset.

[0025] 8, the case where the two-step method is used is explained, but in the case of the one-step method, the Follow_Up message is not used. In this case, the Sync message transmission time T1 and the Sync message processing time (= dt2 - dt1) in Transparent Clock 4, which were included in the Follow_Up message, can be included in the Sync message.

[0026] 9 is a sequence diagram showing an example of the operation of each device in the P2P system, in which the two-step system is used.

[0027] The transparent clock 4 transmits a Pdelay_Req message to the master device at time t1, and stores the time t1 at which the transparent clock 4 transmits the Pdelay_Req message to the master device.

[0028] The master device receives the Pdelay_Req message at time t2 and stores the time t2 when the master device receives the Pdelay_Req message.

[0029] Upon receiving the Pdelay_Req message, the Master device transmits a Pdelay_Resp message to Transparent Clock 4 at time t3. The Master device includes the time t2 at which the Pdelay_Req message was received in the Pdelay_Resp message. The Master device stores the time t3 at which the Pdelay_Resp message was transmitted to Transparent Clock 4.

[0030] After transmitting the Pdelay_Resp message, the Master device transmits a Pdelay_Resp_Follow_Up message to Transparent Clock 4. The Master device includes the time t3 at which the Pdelay_Resp message was transmitted to Transparent Clock 4 in the Pdelay_Resp_Follow_Up message.

[0031] The Transparent Clock 4 receives the Pdelay_Resp message at time t4. The Transparent Clock 4 stores the time t4 when the Pdelay_Resp message is received. The Transparent Clock 4 also receives the Pdelay_Resp_Follow_Up message. The Transparent Clock 4 calculates the transmission delay time pt1 between the Master device and the Transparent Clock 4 using the following equation (2) based on the time t1 when the Transparent Clock 4 transmits the Pdelay_Req message, the time t2 when the Master device receives the Pdelay_Req message contained in the Pdelay_Resp message, the time t3 when the Master device transmits the Pdelay_Resp message contained in the Pdelay_Resp_Follow_Up message, and the time t4 when the Transparent Clock 4 receives the Pdelay_Resp message.

[0032] At time t5, the client device transmits a Pdelay_Req message to the transparent clock 4. The client device stores the time t5 at which the Pdelay_Req message was transmitted to the transparent clock 4.

[0033] The Transparent Clock 4 receives the Pdelay_Req message at time t6 and stores the time t6 at which the Transparent Clock 4 receives the Pdelay_Req message.

[0034] When the Transparent Clock 4 receives the Pdelay_Req message, it transmits a Pdelay_Resp message to the client device at time t7. The Transparent Clock 4 includes the reception time t6 of the Pdelay_Req message in the Pdelay_Resp message. The Transparent Clock 4 stores the transmission time t7 of the Pdelay_Resp message to the client device.

[0035] After transmitting the Pdelay_Resp message, the Transparent Clock 4 transmits a Pdelay_Resp_Follow_Up message to the client device, and includes the time t7 at which the Pdelay_Resp message was transmitted to the client device in the Pdelay_Resp_Follow_Up message.

[0036] The client device receives the Pdelay_Resp message at time t8. The client device stores the time t8 when the Pdelay_Resp message is received. The client device also receives the Pdelay_Resp_Follow_Up message. The client device calculates the transmission delay time pt2 between Transparent Clock 4 and the client device using the following equation (3) based on the time t5 when the client device sends the Pdelay_Req message, the time t6 when the Transparent Clock 4 receives the Pdelay_Req message included in the Pdelay_Resp message, the time t7 when the Transparent Clock 4 sends the Pdelay_Resp message included in the Pdelay_Resp_Follow_Up message, and the time t8 when the client device receives the Pdelay_Resp message: pt2=((t6-t5)+(t8-t7)) / 2 Equation (3)

[0037] The Master device sends a Sync message to Transparent Clock 4 at time T1.

[0038] When the Transparent Clock 4 receives a Sync message at time dt1, it transmits the received Sync message to the Client device at time dt2. The Transparent Clock 4 stores the reception time dt1 of the Sync message from the Master device and the transmission time dt2 of the Sync message to the Client device.

[0039] The client device receives the Sync message sent from Transparent Clock 4 at time T2.

[0040] After transmitting the Sync message, the Master device transmits a Follow_Up message to Transparent Clock 4. The Master device includes the transmission time T1 of the Sync message to Transparent Clock 4 in the Follow_Up message.

[0041] When the Transparent Clock 4 receives the Follow_Up message, it transmits the received Follow_Up message to the Client device. The Transparent Clock 4 sets the CF of the Follow_Up message to a value obtained by adding the transmission delay time pt1 between the Master device and the Transparent Clock 4 and the processing time of the Sync message in the Transparent Clock 4 (=pt1+(dt2-dt1)).

[0042] The client device calculates the reception time T2 of the Sync message at the client device using the following formula (4): T2 = T1 + pt1 + (dt2 - dt1) + pt2 Formula (4) based on the transmission time T1 of the Sync message by the master device, which is included in the Follow_Up message, the transmission delay time pt2 between the transparent clock 4 and the client device, the transmission delay time pt1 between the master device and the transparent clock 4, which is set in the CF of the Follow_Up message, and the processing time of the Sync message at the transparent clock 4.

[0043] The client device synchronizes its internal time with the calculated reception time T2 of the Sync message, thereby synchronizing the internal time of the client device with the internal time of the master device.

[0044] While the two-step method is described in FIG. 9 , the Follow_Up message and the Pdelay_Resp_Follow_Up message are not used in the one-step method. In this case, the transmission time T1 of the Sync message by the Master device, which was included in the Follow_Up message, can be included in the Sync message. The CF of the Sync message can be set to the sum (pt1+(dt2-dt1)) of the transmission delay time pt1 between the Master device and Transparent Clock 4 and the processing time of the Sync message in Transparent Clock 4 (dt2-dt1). The transmission time t3 of the Pdelay_Resp message by the Master device and the transmission time t7 of the Pdelay_Resp message by Transparent Clock 4, which were included in the Pdelay_Resp_Follow_Up message, can be set in the CF of the Pdelay_Resp message.

[0045] The E2E method described with reference to FIG. 8 and the P2P method described with reference to FIG. 9 mainly differ in the following two points.

[0046] The first difference is that the value of CF in the Follow_Up message is different. In the E2E method, the CF of the Follow_Up message sent from Transparent Clock 4 to the Client device is set to the processing time of the Sync message in Transparent Clock 4 (= dt2 - dt1). On the other hand, in the P2P method, the CF of the Follow_Up message sent from Transparent Clock 4 to the Client device is set to the sum of the transmission delay time pt1 between the Master device and Transparent Clock 4 and the processing time of the Sync message in Transparent Clock 4 (= pt1 + (dt2 - dt1)).

[0047] Therefore, the Transparent Clock 4 needs to change the value set in the CF of the Follow_Up message depending on whether the E2E profile or the P2P profile is used.

[0048] The second difference is that the types, transmission sections, and uses of the Req message and the Resp message are different.

[0049] The types of messages are Delay_Req and Delay_Resp messages in the E2E system, whereas they are Pdelay_Req, Pdelay_Resp, and Pdelay_Resp_Follow_Up messages in the P2P system.

[0050] In the E2E method, the message transmission section is between the Master device and the Client, whereas in the P2P method, it is between adjacent devices (between the Master device and Transparent Clock 4, and between Transparent Clock 4 and the Client device).

[0051] In the E2E method, the messages are used to measure and transmit values ​​necessary to calculate the offset between the Master device and the Client device (the sending and receiving times T3 and T4 of the Delay_Req message, and the processing time within the device of the Delay_Req message (dt4-dt3)), whereas in the P2P method, the messages are used to measure the transmission delay time between adjacent devices.

[0052] Therefore, the Transparent Clock 4 needs to change the message transmission section and usage depending on whether the E2E profile or the P2P profile is used.

[0053] Due to the differences described above, it has been necessary to prepare a dedicated device for Transparent Clock 4 for each profile, or to configure Transparent Clock 4 in advance according to the profile.

[0054] The purpose of the present disclosure, made in consideration of the above-mentioned problems, is to provide a communication device, a communication system, and a communication method that can determine a usage profile from multiple profiles that have different methods for measuring transmission delay, and process packets according to the usage profile.

[0055] In order to solve the above problem, the communication device disclosed herein is a communication device that is connected to one of a first device and a second device that are time-synchronized, and that transmits and receives packets with another communication device connected to the other of the first device and the second device, and is equipped with a profile determination unit that determines a usage profile to be used by the first device and the second device from a plurality of profiles that have different methods of measuring transmission delay based on information indicating the type of packet contained in the packet received from the one device or the other communication device, a packet processing determination unit that determines packet processing for the one device and the other communication device according to the determination result of the usage profile, and a packet transmission / reception unit that transmits and receives packets according to the determined packet processing.

[0056] In addition, in order to solve the above problem, the communication system disclosed herein is a communication system comprising a first device and a second device that are time-synchronized, a communication device connected to one of the first device and the second device, and another communication device connected to the other of the first device and the second device, wherein the communication device determines a usage profile to be used by the first device and the second device from a plurality of profiles that have different methods for measuring transmission delay based on information indicating the type of packet contained in the packet received from the first device or the other communication device, determines packet processing for the one device and the other communication device according to the determination result of the usage profile, and transmits and receives packets according to the determined packet processing.

[0057] In addition, in order to solve the above problem, the communication method disclosed herein is a communication method by a communication device that is connected to one of a first device and a second device that are time-synchronized, and that transmits and receives packets with another communication device that is connected to the other of the first device and the second device, and includes the steps of: determining a usage profile that is a profile used by the first device and the second device from a plurality of profiles that have different methods of measuring transmission delay, based on information indicating the type of the packet contained in the packet received from the one device or the other communication device; determining packet processing for the one device and the other communication device according to the result of determining the usage profile; and transmitting and receiving packets according to the determined packet processing.

[0058] According to the communication device, communication system, and communication method disclosed herein, it is possible to determine a usage profile from a plurality of profiles that use different methods for measuring transmission delay, and to process packets in accordance with the usage profile.

[0059] 7B is a diagram illustrating an example configuration of a communication system according to the present disclosure. FIG. 7B is a diagram illustrating time synchronization by the E2E method in the communication system shown in FIG. 1. FIG. 7C is a diagram illustrating time synchronization by the P2P method in the communication system shown in FIG. 1. FIG. 7D is a diagram illustrating an example configuration of a communication device shown in FIG. 1. FIG. 7E is a flowchart illustrating an example of the operation of the communication device shown in FIG. 1. FIG. 7F is a diagram illustrating an example hardware configuration of the communication device shown in FIG. 7C. FIG. 7F is a diagram illustrating an example configuration of a time synchronization system. FIG. 7G is a diagram illustrating another example configuration of a time synchronization system. FIG. 7H is a diagram illustrating time synchronization by the E2E method in the time synchronization system shown in FIG. 7H. FIG. 7H is a diagram illustrating time synchronization by the P2P method in the time synchronization system shown in FIG. 7B.

[0060] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0061] FIG. 1 is a diagram illustrating an example configuration of a communication system 10 according to an embodiment of the present disclosure.

[0062] As shown in FIG. 1, a communication system 10 according to this embodiment includes a Grand Master Clock 1, communication devices 100a and 100b, and a client device 2.

[0063] The Grand Master Clock 1 is a device with a master function that distributes its own internal time. The Client device 2 is a device with a slave function. The Grand Master Clock 1 and the Client device 2 synchronize their times, for example, using the same profile. In the following, it is assumed that the Grand Master Clock 1 and the Client device 2 synchronize their times using an E2E profile or a P2P profile.

[0064] The communication devices 100a and 100b are provided between a Grand Master Clock 1 and a Client device 2 (a first device and a second device). Hereinafter, when there is no need to distinguish between the communication devices 100a and 100b, they will be referred to as the communication devices 100.

[0065] A communication device 100 is connected to one of the Grand Master Clock 1 and the client device 2, and transmits and receives packets (PTP packets) with another communication device 100 connected to the other device. That is, the communication device 100a is connected to the Grand Master Clock 1 and transmits and receives packets with the communication device 100b connected to the client device 2. The communication device 100b is connected to the client device 2 and transmits and receives packets with the communication device 100b connected to the Grand Master Clock 1.

[0066] The communication device 100 determines the profile to be used by the Grand Master Clock 1 and the client device 2 (hereinafter referred to as the "usage profile") from a plurality of profiles (in this embodiment, an E2E profile and a P2P profile) that have different transmission delay measurement methods, based on information indicating the type of packet contained in the packet received from a first device (Grand Master Clock 1 or Client device 2) to which the communication device 100 is connected or another communication device 100. The communication device 100 then determines packet processing for the first device to which the communication device 100 is connected and the other communication device 100 according to the usage profile, and performs the determined packet processing.

[0067] In this way, the communication device 100 according to the present embodiment can determine the usage profile based on the information indicating the type of a received packet and process the packet according to the usage profile, eliminating the need to prepare a dedicated device for each profile or to configure settings according to the profile in advance.

[0068] Next, the operation of each device in the communication system 10 according to this embodiment will be described. As described above, in this embodiment, the Grand Master Clock 1 and the Client device 2 synchronize time using an E2E profile or a P2P profile. First, operation when using an E2E profile will be described with reference to FIG. 2. Note that FIG. 2 illustrates a case where the two-step method is used. In the following description, the transmission and reception times of packets by each device will be appropriately denoted by symbols such as times T1, T2, ..., times t1, t2, ..., and times dt1, dt2, ..., but the numbers included in each symbol are not necessarily assigned in chronological order.

[0069] Since the usage profile of the communication device 100a and the communication device 100b is unknown, the communication device 100a and the communication device 100b are in a standby state. In the standby state, even if the communication device 100a and the communication device 100b receive a Sync message or a Follow_Up message, the communication device 100a and the communication device 100b do not forward the message but discard it internally.

[0070] At time T3, the client device 2 transmits a Delay_Req message to the communication device 100b. As described above, the client device 2 periodically transmits the Delay_Req message.

[0071] At time dt5, the communication device 100b receives a message transmitted from the client device 2. The header information of a Req message such as a Delay_Req message or a Pdelay_Req message includes a messageType that indicates the type of the message. Based on the value of messageType, the communication device 100b can determine the type of the received message (in the example shown in FIG. 2, it is a Delay_Req message used in the E2E system). When the communication device 100b determines that the message received from the client device 2 is a Delay_Req message, it determines that the profile in use is an E2E profile. After determining the profile in use, the communication device 100b releases the standby state.

[0072] When the communication device 100b is released from the standby state, at time dt6, the communication device 100b transmits the Delay_Req message received from the client device 2 to the communication device 100a. The communication device 100b stores the transmission time dt6 of the Delay_Req message.

[0073] At time dt7, communication device 100a receives a Delay_Req message transmitted from communication device 100b. Similar to communication device 100b, communication device 100a determines the type of the received message (in the example shown in FIG. 2, it is a Delay_Req message used in the E2E system) based on the value of messageType included in the header information of the Delay_Req message. When communication device 100a determines that the message received from communication device 100b is a Delay_Req message, it determines that the profile in use is an E2E profile. After determining the profile in use, communication device 100a releases the standby state.

[0074] When the communication device 100a exits the standby state, at time dt8, the communication device 100a transmits the Delay_Req message received from the communication device 100b to Grand Master Clock 1. The communication device 100a stores the transmission time dt8 of the Delay_Req message.

[0075] It is assumed that at time T1 after the communication device 100a has exited the standby state, the Grand Master Clock 1 transmits a Sync message to the communication device 100a.

[0076] When communication device 100a receives the Sync message transmitted from Grand Master Clock 1 at time dt1, it transmits the received Sync message to communication device 100b at time dt2 because it has exited the standby state. Communication device 100a stores the reception time dt1 of the Sync message from Grand Master Clock 1 and the transmission time dt2 of the Sync message to communication device 100b.

[0077] After transmitting the Sync message, the Grand Master Clock 1 transmits a Follow_Up message to the communication device 100a. The Grand Master Clock 1 includes the transmission time T1 of the Sync message in the Follow_Up message.

[0078] When the communication device 100a receives the Follow_Up message transmitted from the Grand Master Clock 1, it transmits the received Follow_Up message to the communication device 100b. The communication device 100a sets the CF of the Follow_Up message to the processing time D1 (= dt2 - dt1) of the Sync message in the communication device 100a.

[0079] When communication device 100b receives the Sync message sent from communication device 100a at time dt3, the standby state is released and, therefore, at time dt4, it sends the received Sync message to client device 2. Communication device 100b stores the time dt3 at which it received the Sync message from communication device 100a and the time dt4 at which it sent the Sync message to client device 2.

[0080] When communication device 100b receives the Follow_Up message transmitted from communication device 100a, it transmits the received Follow_Up message to Client device 2. Communication device 100a sets the CF of the Follow_Up message to a value obtained by adding the processing time D2 (= dt4 - dt3) of the Sync message in communication device 100b. As described above, the CF of the Follow_Up message from communication device 100a is set to the processing time D1 of the Sync message in communication device 100a. Therefore, communication device 100b sets the CF of the Follow_Up message to a value obtained by adding the processing time D1 of the Sync message in communication device 100a and the processing time D2 of the Sync message in communication device 100b (= D1 + D2).

[0081] At time T2, client device 2 receives the Sync message sent from communication device 100b. Client device 2 stores the time T2 at which the Sync message was received. Client device 2 also receives the Follow_Up message sent from communication device 100b.

[0082] Upon receiving the Delay_Req message, the Grand Master Clock 1 transmits a Delay_Resp message to the communication device 100a. The Grand Master Clock 1 includes the reception time T4 of the Delay_Req message in the Delay_Resp message.

[0083] When the communication device 100a receives the Delay_Resp message transmitted from the Grand Master Clock 1, it transmits the received Delay_Resp message to the communication device 100b. The Transparent Clock 4 sets the processing time D4 (= dt8 - dt7) of the Delay_Req message in the communication device 100a in the CF of the Delay_Resp message.

[0084] When communication device 100b receives the Delay_Resp message transmitted from communication device 100a, it transmits the received Delay_Resp message to Client device 2. Transparent Clock 4 sets a value obtained by adding the processing time D3 (= dt6 - dt5) of the Delay_Req message in communication device 100b to the CF of the Delay_Resp message. As described above, the processing time D4 of the Delay_Req message in communication device 100a is set to the CF of the Delay_Resp message. Therefore, communication device 100b sets the CF of the Delay_Resp message to a value obtained by adding the processing time D4 of the Delay_Req message in communication device 100a and the processing time D3 of the Delay_Req message in communication device 100b (= D3 + D4).

[0085] Client device 2 calculates the offset, which is the difference between the device time of Grand Master Clock 1 and the device time of Client device 2, using the following equation (5): Offset = ((T2 - T1 - (D1 + D2)) - (T4 - T3 - (D3 + D4))) / 2 Equation (5)

[0086] 2, the case where the two-step method is used is described, but in the case of the one-step method, the Follow_Up message is not used. In this case, the transmission time T1 of the Sync message by Grand Master Clock 1 and the processing times D1 and D2 of the Sync message by communication devices 100a and 100b, which are included in the Follow_Up message, can be included in the Sync message.

[0087] Next, the operation when a profile of the P2P system is used will be described with reference to Fig. 3. Note that Fig. 3 describes the case when the two-step system is used.

[0088] The communication devices 100a and 100b are in a standby state because they do not know the usage profiles of the Grand Master Clock 1 and the Client device 2. In the standby state, the communication devices 100a and 100b do not forward the Sync message and Follow_Up message even if they receive them, but discard them internally.

[0089] At time t9, the client device 2 transmits a Pdelay_Req message to the communication device 100b. The client device 2 stores the time t9 at which the client device 2 transmits the Pdelay_Req message to the communication device 100b.

[0090] At time t10, the communication device 100b receives a Pdelay_Req message transmitted from the client device 2. The communication device 100b stores the time t10 at which the Pdelay_Req message is received. As described above, the header information of the Pdelay_Req message includes messageType, which indicates the type of the message. Based on the value of messageType, the communication device 100b can determine the type of the received message (in the example shown in FIG. 3, it is a Pdelay_Req message used in the P2P system). When the communication device 100b determines that the message received from the client device 2 is a Pdelay_Req message, it determines that the profile in use is a P2P profile. After determining the profile in use, the communication device 100b cancels the standby state.

[0091] When the communication device 100b exits the standby state, it transmits a Pdelay_Resp message to the client device 2 at time t11. The communication device 100b includes the reception time t10 of the Pdelay_Req message in the Pdelay_Resp message. The communication device 100b stores the transmission time t11 of the Pdelay_Resp message to the client device 2.

[0092] After transmitting the Pdelay_Resp message, the communication device 100b transmits a Pdelay_Resp_Follow_Up message to the client device 2. The communication device 100b includes a transmission time t11 of the Pdelay_Resp message to the client device 2 in the Pdelay_Resp_Follow_Up message.

[0093] At time t12, client device 2 receives the Pdelay_Resp message transmitted from communication device 100b. Client device 2 stores the time t12 when the Pdelay_Resp message is received. Client device 2 also receives the Pdelay_Resp_Follow_Up message. Client device 2 calculates the transmission delay time pt3 between communication device 100b and client device 2 using the following equation (6) based on the time t9 when the client device 2 transmitted the Pdelay_Req message, the time t10 when the client device 2 received the Pdelay_Req message from communication device 100b, which is included in the Pdelay_Resp message, the time t11 when the client device 2 transmitted the Pdelay_Resp message, which is included in the Pdelay_Resp_Follow_Up message, and the time t12 when the client device 2 received the Pdelay_Resp message. pt3=((t10-t9)+(t12-t11)) / 2 Equation (6)

[0094] Furthermore, when the communication device 100b exits the standby state, it transmits a Pdelay_Req message to the communication device 100a at time t5. The communication device 100b stores the time t5 at which the Pdelay_Req message was transmitted to the communication device 100a.

[0095] At time t6, communication device 100a receives a Pdelay_Req message transmitted from communication device 100b. Communication device 100a stores the time t6 when the Pdelay_Req message was received. Similar to communication device 100a, communication device 100a can determine the type of the received message (in the example shown in FIG. 3, it is a Pdelay_Req message used in the P2P system) based on the value of messageType included in the header information of the Pdelay_Req message. When communication device 100a determines that the message received from communication device 100b is a Pdelay_Req message, it determines that the profile in use is a P2P profile. After determining the profile in use, communication device 100a cancels the standby state.

[0096] When the communication device 100a exits the standby state, it transmits a Pdelay_Resp message to the communication device 100b at time t7. The communication device 100a includes the reception time t6 of the Pdelay_Req message in the Pdelay_Resp message. The communication device 100a stores the transmission time t7 of the Pdelay_Resp message to the communication device 100b.

[0097] After transmitting the Pdelay_Resp message, the communication device 100a transmits a Pdelay_Resp_Follow_Up message to the communication device 100b. The communication device 100a includes a transmission time t7 of the Pdelay_Resp message to the communication device 100b in the Pdelay_Resp_Follow_Up message.

[0098] At time t8, communication device 100b receives the Pdelay_Resp message transmitted from communication device 100a. Communication device 100b stores the reception time t8 of the Pdelay_Resp message. Communication device 100b also receives the Pdelay_Resp_Follow_Up message. Based on the transmission time t5 of the Pdelay_Req message by communication device 100b, the reception time t6 of the Pdelay_Req message by communication device 100a which is included in the Pdelay_Resp message, the transmission time t7 of the Pdelay_Resp message by communication device 100a which is included in the Pdelay_Resp_Follow_Up message, and the reception time t8 of the Pdelay_Resp message by communication device 100b, communication device 100b calculates a transmission delay time pt2 between communication device 100a and communication device 100b using the following equation (7): pt2=((t6-t5)+(t8-t7)) / 2 Formula (7)

[0099] Furthermore, when the communication device 100a exits the standby state, at time t1, the communication device 100a transmits a Pdelay_Req message to Grand Master Clock 1. The communication device 100a stores the time t1 at which the Pdelay_Req message was transmitted to Grand Master Clock 1.

[0100] At time t2, the Grand Master Clock 1 receives the Pdelay_Req message transmitted from the communication device 100a and stores the time t2 at which the Pdelay_Req message is received.

[0101] Upon receiving the Pdelay_Req message, the Grand Master Clock 1 transmits a Pdelay_Resp message to the communication device 100a at time t3. The Grand Master Clock 1 includes the reception time t2 of the Pdelay_Req message in the Pdelay_Resp message. The Grand Master Clock 1 stores the transmission time t3 of the Pdelay_Resp message to the communication device 100a.

[0102] After transmitting the Pdelay_Resp message, the Grand Master Clock 1 transmits a Pdelay_Resp_Follow_Up message to the communication device 100a. The Grand Master Clock 1 includes the transmission time t3 of the Pdelay_Resp message to the communication device 100a in the Pdelay_Resp_Follow_Up message.

[0103] At time t4, the communication device 100a receives a Pdelay_Resp message transmitted from Grand Master Clock 1. The communication device 100a stores the reception time t4 of the Pdelay_Resp message. The communication device 100a also receives a Pdelay_Resp_Follow_Up message. The communication device 100a calculates a transmission delay time pt1 between Grand Master Clock 1 and the communication device 100a using the following equation (8) based on the transmission time t1 of the Pdelay_Req message by the communication device 100a, the reception time t2 of the Pdelay_Req message by Grand Master Clock 1 which is included in the Pdelay_Resp message, the transmission time t3 of the Pdelay_Resp message by Grand Master Clock 1 which is included in the Pdelay_Resp_Follow_Up message, and the reception time t4 of the Pdelay_Resp message by the communication device 100a. pt1=((t2-t1)+(t4-t3)) / 2 Equation (8)

[0104] It is assumed that at time T1 after the communication device 100a has exited the standby state, the Grand Master Clock 1 transmits a Sync message to the communication device 100a.

[0105] When communication device 100a receives the Sync message transmitted from Grand Master Clock 1 at time dt1, it transmits the received Sync message to communication device 100b at time dt2 because it has exited the standby state. Communication device 100a stores the reception time dt1 of the Sync message from Grand Master Clock 1 and the transmission time dt2 of the Sync message to communication device 100b.

[0106] After transmitting the Sync message, the Grand Master Clock 1 transmits a Follow_Up message to the communication device 100a. The Grand Master Clock 1 includes the transmission time T1 of the Sync message in the Follow_Up message.

[0107] When the communication device 100a receives the Follow_Up message transmitted from Grand Master Clock 1, it transmits the received Follow_Up message to the communication device 100b. The communication device 100a sets the CF of the Follow_Up message to a value (=pt1+D1) obtained by adding the processing time D1 (=dt2-dt1) of the Sync message in the communication device 100a and the transmission delay time pt1 between Grand Master Clock 1 and the communication device 100a.

[0108] When communication device 100b receives the Sync message sent from communication device 100a at time dt3, the standby state is released and, therefore, at time dt4, it sends the received Sync message to client device 2. Communication device 100b stores the time dt3 at which it received the Sync message from communication device 100a and the time dt4 at which it sent the Sync message to client device 2.

[0109] When communication device 100b receives the Follow_Up message transmitted from communication device 100a, it transmits the received Follow_Up message to Client device 2. Communication device 100a sets the CF of the Follow_Up message to a value (=pt2+D2) obtained by adding the processing time D2 (=dt4-dt3) of the Sync message in communication device 100b and the transmission delay time pt2 between communication device 100a and communication device 100b. As described above, the CF of the Follow_Up message from communication device 100a sets the value (=pt1+D1) obtained by adding the processing time D1 of the Sync message in communication device 100a and the transmission delay time pt1 between Grand Master Clock 1 and communication device 100a. Therefore, communication device 100b sets the CF of the Follow_Up message to a value (= pt1 + D1 + pt2 + D2) obtained by adding the processing time D1 of the Sync message in communication device 100a, the transmission delay time pt1 between Grand Master Clock 1 and communication device 100a, the processing time D2 of the Sync message in communication device 100b, and the transmission delay time pt2 between communication device 100a and communication device 100b.

[0110] At time T2, client device 2 receives the Sync message sent from communication device 100b. Client device 2 stores the time T2 at which the Sync message was received. Client device 2 also receives the Follow_Up message sent from communication device 100b.

[0111] The client device 2 calculates the reception time T2 of the Sync message at the client device 2 using the following formula (9): T2 = T1 + pt1 + D1 + pt2 + D2. This is the sum of the transmission time T1 of the Sync message by the Grand Master Clock 1, which is included in the Follow_Up message, the transmission delay time pt3 between the communication device 100b and the client device 2, the processing time D1 of the Sync message at the communication device 100a, the transmission delay time pt1 between the Grand Master Clock 1 and the communication device 100a, the processing time D2 of the Sync message at the communication device 100b, and the transmission delay time pt2 between the communication device 100a and the communication device 100b.

[0112] 3 illustrates the case where the two-step method is used, but in the case of the one-step method, the Follow_Up message and the Pdelay_Resp_Follow_Up message are not used. In this case, the transmission time T1 of the Sync message by Grand Master Clock 1 and the transmission delay times pt1 and pt2, which were included in the Follow_Up message, can be included in the Sync message. Also, the transmission time T3 of the Pdelay_Resp message by Grand Master Clock 1, the transmission time T7 of the Pdelay_Resp message by communication device 100a, and the transmission time T11 of the Pdelay_Resp message by communication device 100b, which were included in the Pdelay_Resp_Follow_Up message, can be included in the Pdelay_Resp message.

[0113] In this way, in this embodiment, the communication device 100 determines the usage profile from multiple profiles that have different methods for measuring transmission delay based on information indicating the type of the received packet (Req message) and is able to process the packet according to the usage profile.

[0114] Next, the configuration of the communication device 100 will be described.

[0115] Fig. 4 is a diagram showing an example of the configuration of a communication device 100 according to this embodiment. In Fig. 4, it is assumed that the profile used by the Grand Master Clock 1 and the client device 2 is an E2E profile or a P2P profile.

[0116] As shown in FIG. 4, the communication device 100 according to this embodiment includes packet transmitting / receiving units 101 and 102, an E2E / P2P determination unit 103 as a profile determination unit, an E2E processing unit 104, a P2P processing unit 105, and a packet processing determination unit 106.

[0117] The packet transmitter / receiver 101 transmits and receives packets (PTP packets) to and from the Grand Master Clock 1 or the client device 2. In the communication device 100a, the packet transmitter / receiver 101 transmits and receives packets to and from the Grand Master Clock 1. In the communication device 100b, the packet transmitter / receiver 101 transmits and receives packets to and from the client device 2. The packet transmitter / receiver 101 outputs packets received from the Grand Master Clock 1 or the client device 2 to the E2E / P2P determination unit 103, the E2E processing unit 104, or the P2P processing unit 105, depending on the received packet.

[0118] The packet transmitter / receiver 102 transmits and receives packets to and from other communication devices 100. In communication device 100a, the packet transmitter / receiver 102 transmits and receives packets to and from communication device 100b. In communication device 100b, the packet transmitter / receiver 102 transmits and receives packets to and from communication device 100a. The packet transmitter / receiver 102 outputs packets received from other communication devices 100 to the E2E / P2P determination unit 103, the E2E processing unit 104, or the P2P processing unit 105, depending on the received packet.

[0119] The E2E / P2P determination unit 103 determines the profiles used by the Grand Master Clock 1 and the client device 2 based on the packets output from the packet transmitter / receiver 101 or the packet transmitter / receiver 102. For example, if the communication device 100 is the communication device 100b, the E2E / P2P determination unit 103 determines the profile used based on information (messageType) included in the header information of the Req message (Delay_Req message or Pdelay_Req message) sent by the client device 2 and output from the packet transmitter / receiver 101, as described with reference to Figures 2 and 3. Also, if the communication device 100 is the communication device 100a, the E2E / P2P determination unit 103 determines the profile used based on information (messageType) included in the header information of the Req message (Delay_Req message or Pdelay_Req message) sent by the communication device 100b and output from the packet transmitter / receiver 101, as described with reference to Figures 2 and 3.

[0120] The E2E / P2P determination unit 103 notifies the packet processing determination unit 106 of the determination result.

[0121] When the profile in the E2E system is the profile in use, the E2E processing unit 104 processes packets transmitted to and received from other devices via the packet transmitting / receiving units 101 and 102 as E2E packets.

[0122] When the profile for the P2P system is the profile in use, the P2P processing unit 105 processes packets transmitted to and received from other devices via the packet transmitting / receiving units 101 and 102 as P2P packets.

[0123] The packet processing determination unit 106 determines packet processing for one of the Grand Master Clock 1 and the Client device 2 to which the communication device 100 is connected, and for the other communication device 100, in accordance with the determination result of the usage profile by the E2E / P2P determination unit 103. The packet processing determination unit 106 instructs the packet transmission / reception units 101 and 102 on the determined packet processing. The packet transmission / reception units 101 and 102 transmit and receive packets in accordance with the packet processing determined by the packet processing determination unit 106.

[0124] The packet processing determination unit 106 determines that packet transmission and reception should be suspended as packet processing until the usage profile is determined. Specifically, as described with reference to FIGS. 2 and 3 , the packet processing determination unit 106 does not allow the packet transmission and reception units 101 and 102 to transmit a Sync message or a Follow_Up message even if the unit 106 receives these messages until the usage profile is determined.

[0125] Furthermore, in a typical P2P profile, a Pdelay_Req message is periodically transmitted. However, in the communication device 100 according to this embodiment, the packet processing determination unit 106 does not cause the packet transmission / reception units 101 and 102 to transmit a Pdelay_Req message until the profile in use is determined.

[0126] Furthermore, when the usage profile is determined, the packet processing determination unit 106 determines the packet processing to be performed between one of the Grand Master Clock 1 and the Client device 2 to which the communication device 100 is connected, and the other communication device 100, in accordance with the usage profile.

[0127] Next, the operation of the communication device 100 according to this embodiment will be described.

[0128] FIG. 5 is a flowchart showing an example of the operation of the communication device 100 according to this embodiment, and is a diagram for explaining a communication method by the communication device 100 according to this embodiment.

[0129] When the communication device 100 receives a packet, the packet processing determination unit 106 determines whether the usage profile has been determined by the E2E / P2P determination unit 103 (step S101). Specifically, the packet processing determination unit 106 determines whether the usage profile has been notified by the E2E / P2P determination unit 103.

[0130] If it is determined that the used profile is an E2E profile (step S101: Yes (E2E)), the packet processing determination unit 106 determines packet processing corresponding to the E2E method and causes the packet transmission / reception units 101 and 102 to transmit and receive packets in accordance with the determined packet processing (step S102).

[0131] If it is determined that the used profile is a P2P profile (step S101: Yes (P2P)), the packet processing determination unit 106 determines packet processing corresponding to the P2P method and causes the packet transmission / reception units 101 and 102 to transmit and receive packets in accordance with the determined packet processing (step S103).

[0132] If the used profile has not been determined (step S101: No), the packet processing determination unit 106 determines the packet processing to be standby processing, and instructs the packet transmission / reception units 101 and 102 to perform standby processing, which does not transmit packets to other devices (step S104).

[0133] The packet transmitters and receivers 101 and 102 perform standby processing in accordance with the instruction from the packet processing determination unit 106 (step S105). For example, even if the packet transmitter and receiver 101 receives a Sync message and a Follow_Up message from Grand Master Clock 1, the packet transmitter and receiver 102 does not transmit these messages to the communication device 100b. Also, normally, the communication device 100b periodically transmits a Pdelay_Req message to the communication device 100a, and the communication device 100a periodically transmits a Pdelay_Req message to Grand Master Clock 1. When standby processing is instructed, the packet transmitters and receivers 101 and 102 do not transmit a Pdelay_Req message.

[0134] The E2E / P2P determining unit 103 determines the usage profile based on the packet (message) received by the communication device 100 (step S106).

[0135] If the E2E / P2P determination unit 103 cannot determine the profile in use, for example, because the message received by the communication device 100 is a Sync message (step S106: determination impossible), it notifies the packet processing determination unit 106 that the profile in use cannot be determined. When the packet processing determination unit 106 is notified that the profile in use cannot be determined, it returns to the processing of step S104.

[0136] When the E2E / P2P determination unit 103 determines that the profile in use is an E2E profile (step S106: E2E), it notifies the packet processing determination unit 106 of the determination result (step S107). When the packet processing determination unit 106 is notified of the determination result that the profile in use is an E2E profile, it proceeds to the process of step S102.

[0137] When the E2E / P2P determination unit 103 determines that the profile in use is a P2P profile (step S106: P2P), it notifies the packet processing determination unit 106 of the determination result (step S108). When the packet processing determination unit 106 is notified of the determination result that the profile in use is a P2P profile, it proceeds to the process of step S103.

[0138] As described above, the communication device 100 according to this embodiment includes an E2E / P2P determination unit 103, a packet processing determination unit 106, and packet transmission / reception units 101 and 102. The E2E / P2P determination unit 103 determines a usage profile from a plurality of profiles that have different transmission delay measurement methods, based on information indicating a packet type included in a packet received from one of the Grand Master Clock 1 and the Client device 2 or from the other communication device 100. The packet processing determination unit 106 determines packet processing for the one device and the other communication device 100 according to the determination result of the usage profile. The packet transmission / reception units 101 and 102 perform the determined packet processing.

[0139] In addition, the communication method by the communication device 100 according to this embodiment includes the steps of: determining a usage profile, which is a profile used by the Grand Master Clock 1 and the Client device 2, from a plurality of profiles having different methods of measuring transmission delay, based on information indicating the packet type contained in a packet received from one of the Grand Master Clock 1 and the Client device 2 or another communication device 100 (step S106); determining packet processing for the one device and the other communication device 100 according to the result of determining the usage profile (steps S102, 103); and performing the determined packet processing (steps S102, 103).

[0140] Based on information indicating the type of a received packet, the communication device 100 can determine the profile to be used from among multiple profiles that have different methods for measuring transmission delay. Therefore, the communication device 100 according to this embodiment can determine the profile to be used (profile to be used) from among multiple profiles that have different methods for measuring transmission delay, and process the packet according to the profile to be used.

[0141] Next, the hardware configuration of the communication device 100 according to the present disclosure will be described.

[0142] 6 is a diagram illustrating an example of a hardware configuration of a communication device 100 according to the present disclosure. In FIG. 6, an example of the hardware configuration of the communication device 100 is illustrated, in which the communication device 100 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.

[0143] 6, the communication device 100 includes a processor 201, a read-only memory (ROM) 202, a random access memory (RAM) 203, a storage 204, an input unit 205, a display unit 206, and a communication interface (I / F) 207. Each component is communicably connected to one another via a bus 209. The processor 201 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 multiple processors of the same type or different types.

[0144] The processor 201 is a control unit that controls each component and performs various arithmetic processing. That is, the processor 201 reads a program from the ROM 202 or the storage 204 and executes the program using the RAM 203 as a work area. The processor 201 controls each component and performs various arithmetic processing in accordance with the program stored in the ROM 202 or the storage 204. In this embodiment, the ROM 202 or the storage 204 stores a program for operating a computer as the communication device 100 according to the present disclosure. The program is read and executed by the processor 201, thereby realizing each component of the communication device 100 described above.

[0145] 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.

[0146] The ROM 202 stores various programs and various data. The RAM 203 temporarily stores programs or data as a working area. The storage 204 is configured with an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs including the operating system and various data.

[0147] The input unit 205 includes a pointing device such as a mouse and a keyboard, and is used to input various types of information.

[0148] The display unit 206 is, for example, a liquid crystal display, and displays various information. The display unit 206 may be a touch panel type and function as the input unit 205.

[0149] The communication interface 207 is an interface for communicating with other devices (for example, the Grand Master Clock 1, the client device 2, or other communication devices 100).

[0150] A computer can be suitably used to function as each unit of the above-described communication device 100. Such a computer can be realized by storing a program describing the processing content for realizing the functions of each unit of the communication device 100 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 device 100. The program can also be recorded on a non-transitory storage medium. The program can also be provided via a network.

[0151] The following additional notes are provided regarding the above-described embodiments.

[0152] [Supplementary Item 1] A communication device connected to one of a first device and a second device that are time-synchronized, and that transmits and receives packets with another communication device connected to the other of the first device and the second device, comprising a control unit, wherein the control unit is configured to: determine a usage profile to be used by the first device and the second device from a plurality of profiles that have different methods of measuring transmission delay, based on information indicating a type of packet contained in the packet received from the one device or the other communication device; determine packet processing for the one device and the other communication device according to the determination result of the usage profile; and transmit and receive packets according to the determined packet processing.

[0153] [Supplementary Item 2] In the communication device described in Supplementary Item 1, the control unit determines that the packet processing is to wait for packet transmission and reception until the usage profile is determined, and once the usage profile is determined, determines that the packet processing is to transmit and receive packets between the one device and the other communication device in accordance with the usage profile.

[0154] [Supplementary Item 3] A communication system comprising a first device and a second device that are time-synchronized, a communication device connected to one of the first device and the second device, and another communication device connected to the other of the first device and the second device, wherein the communication device determines a usage profile to be used by the first device and the second device from a plurality of profiles that have different methods of measuring transmission delay based on information indicating a type of packet contained in the packet received from the first device or the other communication device, determines packet processing for the one device and the other communication device according to the determination result of the usage profile, and transmits and receives packets according to the determined packet processing.

[0155] [Supplementary Item 4] A communication method by a communication device that is connected to one of a first device and a second device that are time-synchronized, and that transmits and receives packets with another communication device that is connected to the other of the first device and the second device, the method comprising: determining a usage profile that is a profile to be used by the first device and the second device from a plurality of profiles that have different methods for measuring transmission delay, based on information indicating a type of the packet contained in the packet received from the one device or the other communication device; determining packet processing for the one device and the other communication device according to the determination result of the usage profile; and transmitting and receiving packets according to the determined packet processing.

[0156] 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.

[0157] REFERENCE SIGNS LIST 1 Grand Master Clock (first device) 2 Client device (second device) 3 Boundary Clock 4 Transparent Clock 10 Communication system 100 Communication device 101, 102 Packet transmitting / receiving unit 103 E2E / P2P determining unit (profile determining unit) 104 E2E processing unit 105 P2P processing unit 106 Packet processing determining unit 201 Processor 202 ROM 203 RAM 204 Storage 205 Input unit 206 Display unit 207 Communication I / F 209 Bus

Claims

1. A communication device connected to one of a first device and a second device that are time-synchronized, and transmitting and receiving packets with another communication device connected to the other of the first device and the second device, comprising: a profile determination unit that determines a usage profile to be used by the first device and the second device from a plurality of profiles that have different methods of measuring transmission delay based on information indicating a type of packet contained in a packet received from the one device or the other communication device; a packet processing determination unit that determines packet processing for the one device and the other communication device in accordance with the result of the usage profile determination; and a packet transmission / reception unit that transmits and receives packets in accordance with the determined packet processing.

2. A communications device as described in claim 1, wherein the packet processing determination unit determines that the packet processing is to wait for packet transmission / reception until the usage profile is determined, and once the usage profile is determined, determines that the packet processing is to transmit / receive packets between the one device and the other communications device in accordance with the usage profile.

3. A communication system comprising a first device and a second device which are time-synchronized, a communication device connected to one of the first device and the second device, and another communication device connected to the other of the first device and the second device, wherein the communication device determines a usage profile to be used by the first device and the second device from a plurality of profiles having different methods of measuring transmission delay based on information indicating a type of packet contained in the packet received from the first device or the other communication device, determines packet processing for the one device and the other communication device according to the result of determining the usage profile, and transmits and receives packets according to the determined packet processing.

4. A communication method by a communication device connected to one of a first device and a second device that are time-synchronized, and transmitting and receiving packets with another communication device connected to the other of the first device and the second device, comprising the steps of: determining a usage profile, which is a profile used by the first device and the second device, from a plurality of profiles having different methods of measuring transmission delay, based on information indicating the type of the packet contained in the packet received from the one device or the other communication device; determining packet processing for the one device and the other communication device according to the result of determining the usage profile; and transmitting and receiving packets according to the determined packet processing.

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