Communication device, communication system, and communication method

Abstract

A communication device (100) comprises: a port determination unit (103) for determining whether a first port for transmitting / receiving packets to / from one or more higher-level devices and a second port for transmitting / receiving packets to / from one or more lower-level devices are each the common port or a single port for transmitting / receiving packets of a single profile; a packet processing determination unit (106) for determining packet processing for the higher-level device and the lower-level device; and packet transmission / reception units (101, 102) for transmitting / receiving packets according to the determined packet processing. When transmitting / receiving a packet at a port determined to be the common port, the packet processing determination unit (106) determines, as the packet processing, transmission / reception of the packet via a logical port corresponding to the profile of the packet.

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, in order for the Transparent Clock 4 to process both E2E and P2P messages, it is necessary to determine whether the message is an E2E Follow_Up message or a P2P Follow_Up message.

[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, in order for Transparent Clock 4 to process both E2E and P2P messages, the transmission section and usage must be changed depending on the type of message.

[0053] Due to the differences described above, devices using different profiles could not synchronize time with each other, and devices using the same profile had to be connected. Therefore, users of PTP had to build time distribution networks that used a single profile for each field, resulting in increased costs. Furthermore, network operators found it difficult to efficiently use their networks because a time distribution network used in one field could not generally distribute time to users in other fields. Therefore, there is a demand for technology that can distribute time to users in different fields (users using different profiles) over a single network.

[0054] As a configuration for realizing time synchronization using different profiles on a single network, for example, as shown in Fig. 10A, multiple Boundary Clocks 3 (in the example shown in Fig. 10A, three Boundary Clocks 3a, 3b, and 3c) are provided between Grand Master Clocks 1a and 1b that use different profiles and Client devices 2a and 2b that use different profiles, and the time is synchronized sequentially between adjacent devices. However, the Boundary Clock 3 can only synchronize time with one Grand Master Clock 1. Therefore, in the configuration shown in Fig. 10A, the Boundary Clock 3a cannot synchronize time with both the Grand Master Clocks 1a and 1b.

[0055] Another possible configuration for achieving time synchronization using different profiles on a single network is, for example, a configuration as shown in FIG. 10B in which multiple transparent clocks 4 (three transparent clocks 4a, 4b, and 4c in the example shown in FIG. 10B) are provided between grand master clocks 1a and 1b and client devices 2a and 2b. In this configuration, adjacent transparent clocks 4 are connected by a single line, and messages of multiple profiles are superimposed and transmitted between adjacent transparent clocks 4 on a single line. However, the transparent clock 4 cannot simultaneously process packets of different profiles on a single port corresponding to a single line. Therefore, in the configuration shown in FIG. 10B, packets of different profiles cannot be sequentially transferred between the grand master clock 1 and client device 2, and time synchronization using different profiles cannot be achieved on a single network.

[0056] Another possible configuration for achieving time synchronization using different profiles on a single network is, for example, a configuration as shown in FIG. 10C in which multiple transparent clocks 4 (three transparent clocks 4a, 4b, and 4c in the example shown in FIG. 10C ) are provided between grand master clocks 1a and 1b and client devices 2a and 2b. In this configuration, dedicated ports and lines are provided for each profile between adjacent transparent clocks 4. By setting the time correction method and PTP packet route for each port in advance, the grand master clock 1 and client device 2 can be time-synchronized for each of the multiple profiles. However, the configuration shown in FIG. 10C requires dedicated ports and lines for each profile, which increases the cost of building the system.

[0057] As described above, even when the conventional Boundary Clock 3 and Transparent Clock 4 are used, it is difficult to achieve time synchronization using different profiles on a single network.

[0058] 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 send and receive packets (PTP packets) of different profiles while suppressing increases in costs.

[0059] In order to solve the above problem, the communication device of the present disclosure is a communication device that is provided in multiple locations between a first device and a second device that are time-synchronized, and that transmits and receives packets for the time synchronization, and has a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port is a common port that transmits and receives packets of multiple profiles that have different transmission delay measurement methods, and a logical port corresponding to each of the multiple profiles is set in the common port, and the communication device is equipped with a port determination unit that determines whether the first port and the second port are the common port or a single port that transmits and receives packets of a single profile, a packet processing determination unit that determines packet processing for the higher-level device and the lower-level device, and a packet transmission / reception unit that transmits and receives packets in accordance with the determined packet processing, and when transmitting and receiving a packet via a port determined to be the common port, the packet processing determination unit determines that the packet processing will be transmitting and receiving the packet via the logical port corresponding to the profile of the packet.

[0060] In addition, in order to solve the above problem, a communication system according to the present disclosure includes a first device and a second device that time-synchronize, and a plurality of communication devices that are provided between the first device and the second device and that transmit and receive packets for the time synchronization, the communication devices having a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port being a common port that transmits and receives packets of a plurality of profiles that have different transmission delay measurement methods, and a logical port corresponding to each of the plurality of profiles is set in the common port, and the system includes a port determination unit that determines whether the first port and the second port are the common port or a single port that transmits and receives packets of a single profile, a packet processing determination unit that determines packet processing for the higher-level device and the lower-level device, and a packet transmission / reception unit that transmits and receives packets in accordance with the determined packet processing, and when a packet is transmitted or received via a port determined to be the common port, the packet processing determination unit determines that the packet processing will be the transmission and reception of the packet via a logical port corresponding to the profile of the packet.

[0061] In addition, in order to solve the above problem, the communication method disclosed herein is a communication method using a communication device that is provided in multiple locations between a first device and a second device that are time-synchronized and that transmits and receives packets for the time synchronization, wherein the communication device has a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port is a common port that transmits and receives packets of multiple profiles that have different transmission delay measurement methods, and a logical port corresponding to each of the multiple profiles is set in the common port, and the method includes the steps of determining whether the first port and the second port are the common port or a single port that transmits and receives packets of a single profile, determining packet processing for the higher-level device and the lower-level device, and transmitting and receiving packets in accordance with the determined packet processing, and when a packet is transmitted or received via a port determined to be the common port, the packet processing is determined to be the transmission and reception of the packet via a logical port corresponding to the profile of the packet.

[0062] According to the communication device, communication system, and communication method disclosed herein, packets of different profiles can be transmitted and received while suppressing increases in costs.

[0063] 7B is a diagram illustrating an example of a configuration of a communication system according to the present disclosure. FIG. 7B is a diagram illustrating time synchronization using the E2E method in the communication system shown in FIG. 1. FIG. 7C is a diagram illustrating time synchronization using the P2P method in the communication system shown in FIG. 1. FIG. 7D is a diagram illustrating an example of a configuration of a communication device shown in FIG. 1. FIG. 7E is a flowchart illustrating an example of an operation of the communication device shown in FIG. 1. FIG. 7F is a diagram illustrating an example of a hardware configuration of the communication device shown in FIG. 7C. FIG. 7G is a diagram illustrating an example of a configuration of a time synchronization system. FIG. 7H is a diagram illustrating another example of a configuration of a time synchronization system. FIG. 7H is a diagram illustrating time synchronization using the E2E method in the time synchronization system shown in FIG. 7B. FIG. 7H is a diagram illustrating time synchronization using the P2P method in the time synchronization system shown in FIG. 7B. FIG. 7H is a diagram illustrating an example of a network configuration assumed for time synchronization using different profiles. FIG. 7I is a diagram illustrating another example of a network configuration assumed for time synchronization using different profiles. FIG. 7I is a diagram illustrating a further example of a network configuration assumed for time synchronization using different profiles.

[0064] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0065] FIG. 1 is a diagram illustrating an example configuration of a communication system 10 according to an embodiment of the present disclosure.

[0066] As shown in FIG. 1, a communication system 10 according to this embodiment includes Grand Master Clocks 1a and 1b, communication devices 100a, 100b, and 100c, and client devices 2a and 2b.

[0067] Grand Master Clocks 1a and 1b, which function as first devices, are devices equipped with a master function that distributes their own internal time. Grand Master Clock 1a and Grand Master Clock 1b use different profiles for time synchronization. In the following description, the profiles are assumed to be an E2E profile and a P2P profile, which use different methods for measuring transmission delay.

[0068] The client devices 2a and 2b, which are second devices, are devices equipped with slave functions. The client devices 2a and 2b use different profiles for time synchronization. For example, the Grand Master Clock 1a and the client device 2a use the same profile for time synchronization. The Grand Master Clock 1b and the client device 2b also use the same profile for time synchronization.

[0069] The communication devices 100a, 100b, and 100c are provided between the Grand Master Clocks 1a and 1b and the Client devices 2a and 2b, and transmit and receive packets (PTP packets) for time synchronization. Hereinafter, when there is no need to distinguish between the communication devices 100a, 100b, and 100c, they will be referred to as the communication device 100.

[0070] The communication device 100 has a port (first port) for transmitting and receiving packets to and from one or more higher-level devices, and a port (second port) for transmitting and receiving packets to and from one or more lower-level devices. The higher-level device is a device adjacent to the communication device 100 that is on the Grand Master Clock 1 side. The lower-level device is a device adjacent to the communication device 100 that is on the Client device 2 side.

[0071] The communication device 100a has a port for transmitting and receiving packets with multiple Grand Master Clocks 1a and 1b, which are higher-level devices, and a port for transmitting and receiving packets with one communication device 100b, which is a lower-level device, and transmits and receives packets between the Grand Master Clocks 1a and 1b and the communication device 100b. The communication device 100b has a port for transmitting and receiving packets with one communication device 100a, which is a higher-level device, and a port for transmitting and receiving packets with one communication device 100c, which is a lower-level device, and transmits and receives packets between the communication device 100a and the communication device 100c. The communication device 100c has a port for transmitting and receiving packets with one communication device 100b, which is a higher-level device, and a port for transmitting and receiving packets with multiple client devices 2a and 2b, which are lower-level devices, and transmits and receives packets between the communication device 100b and the client devices 2a and 2b.

[0072] 1, the communication device 100a transmits and receives packets to and from the Grand Master Clocks 1a and 1b via individual ports and lines. Therefore, the port corresponding to the Grand Master Clock 1a transmits and receives packets of the profile used by the Grand Master Clock 1a, and the port corresponding to the Grand Master Clock 1b transmits and receives packets of the profile used by the Grand Master Clock 1b. In other words, packets of a single profile are transmitted and received at each port on the higher-level device side of the communication device 100a.

[0073] Furthermore, the communication device 100c transmits and receives packets to and from the client devices 2a and 2b via individual ports and lines. Therefore, the port corresponding to the client device 2a transmits and receives packets of the profile used by the client device 2a, and the port corresponding to the client device 2b transmits and receives packets of the profile used by the client device 2b. In other words, packets of a single profile are transmitted and received at each of the ports on the lower device side of the communication device 100c. Hereinafter, a port through which packets of a single profile are transmitted and received is referred to as a single port.

[0074] Furthermore, the communication devices 100a and 100b transmit and receive packets via a single line. Furthermore, the communication devices 100b and 100c transmit and receive packets via a single line. As described above, the communication device 100a transmits and receives packets with a profile different from that of the Grand Master Clocks 1a and 1b, and the communication device 100c transmits and receives packets with a profile different from that of the client devices 2a and 2b. Therefore, packets with multiple profiles that use different transmission delay measurement methods are transmitted and received between the communication devices 100a and 100b, and between the communication devices 100b and 100c. In other words, packets with multiple profiles that use different transmission delay measurement methods are transmitted and received between the lower-level device port of the communication device 100a, the upper-level device port of the communication device 100b, the lower-level device port of the communication device 100b, and the upper-level device port of the communication device 100c. Hereinafter, a port that transmits and receives packets with multiple profiles that use different transmission delay measurement methods is referred to as a common port.

[0075] As described above, the port of communication device 100a on the upper device side is a single port, and the port of communication device 100a on the lower device side is a common port. The port of communication device 100b on the upper device side is a common port, and the port of communication device 100b on the lower device side is a common port. The port of communication device 100c on the upper device side is a common port, and the port of communication device 100c on the lower device side is a single port. In this way, at least one of the first port and the second port provided in communication device 100 is a common port that transmits and receives packets of multiple profiles that have different transmission delay measurement methods.

[0076] In the communication system 10 according to this embodiment, logical ports corresponding to each of a plurality of profiles are set as a common port. When a packet is sent or received through a port determined to be a common port, the packet is sent or received via the logical port corresponding to the profile of the packet. In this way, even when packets of multiple profiles are superimposed on a single line, the packets of each profile can be sorted and sent or received.

[0077] In this manner, in the communication system 10 according to the present embodiment, packets of multiple profiles with different transmission delay measurement methods are transmitted and received via a common port between the communication device 100a and the communication device 100b, and between the communication device 100b and the communication device 100c. When a packet is transmitted and received via a port determined to be a common port, the packet is transmitted and received via a logical port corresponding to the profile of the packet.

[0078] This eliminates the need to provide a port and a line for each profile, as shown in Fig. 10C. This eliminates the need to add ports and lines, and makes it possible to send and receive packets of different profiles while suppressing increases in costs.

[0079] Next, the operation of each device in the communication system 10 according to this embodiment will be described. In the following description, the profiles are assumed to be an E2E profile and a P2P profile, which use different methods for measuring transmission delay. Also, in the following description, it is assumed that the Grand Master Clock 1a and the Client device 2a use the E2E profile, and the Grand Master Clock 1b and the Client device 2b use the P2P profile. Note that the packet transmission times and reception times of each device are appropriately denoted by symbols such as time T1, T2, ..., time t1, t2, ..., and time dt1, dt2, ..., but the numbers included in each symbol are not necessarily assigned in chronological order.

[0080] First, the operation when time synchronization is performed between the Grand Master Clock 1a and the Client device 2a using the E2E profile will be described with reference to FIG.

[0081] The communication device 100 determines for each port whether the port is a common port or a single port. For example, when the communication device 100 receives messages containing multiple domain numbers via a port, it determines that the port is a common port, and when it receives only messages containing the same domain number, it determines that the port is a single port. The domain number indicates the group of devices that perform time synchronization.

[0082] Furthermore, for example, when communication device 100 receives both packets used in an E2E profile (Delay_Req message, Delay_Resp message) and packets used in a P2P profile (Pdelay_Req message, Pdelay_Resp message) via a port, it determines that the port is a common port, and when it receives packets used in only one of the profiles, it determines that the port is a single port. Note that the method for determining whether a port is a common port or a single port is not limited to the above-described method, and any method may be used as long as it is possible to make the determination using packets of different profiles.

[0083] As described above, packets of multiple profiles are transmitted and received between communication device 100a and communication device 100b, and between communication device 100b and communication device 100c. Therefore, the lower device side port of communication device 100a, the upper device side port of communication device 100b, the lower device side port of communication device 100b, and the upper device side port of communication device 100c are determined to be common ports.

[0084] On the other hand, packets are transmitted and received between the communication device 100a and the Grand Master Clocks 1a and 1b via individual ports and lines. Packets are transmitted and received between the communication device 100c and the Client devices 2a and 2b via individual ports and lines. Therefore, the port on the higher-level device side of the communication device 100a (the port connected to the Grand Master Clocks 1a and 1b) and the port on the lower-level device side of the communication device 100c (the port connected to the Client devices 2a and 2b) are determined to be single ports.

[0085] A logical port corresponding to each of the multiple profiles is set for a port determined to be a common port. As described above, the lower-level device port of communication device 100a, the upper-level device port of communication device 100b, the lower-level device port of communication device 100b, and the upper-level device port of communication device 100c are common ports. Therefore, as shown in Figure 2, a logical port corresponding to each of the multiple profiles (in this embodiment, an E2E-based profile and a P2P-based profile) is set for these ports.

[0086] The communication device 100 determines the profile of packets transmitted and received via a port determined to be a single port. For example, when the communication device 100 receives a Delay_Req message or a Delay_Resp message used in an E2E profile via a port determined to be a single port, the communication device 100 determines that the profile of packets transmitted and received via the port is the E2E profile. Also, when the communication device 100 receives a Pdelay_Req message or a Pdelay_Resp message used in a P2P profile via a port determined to be a single port, the communication device 100 determines that the profile of packets transmitted and received via the port is the P2P profile.

[0087] 2, a Delay_Req message is sent from client device 2a, which uses an E2E profile, so the profile of packets transmitted and received at a port of communication device 100c connected to client device 2a is determined to be the E2E profile. Also, a Delay_Resp message is sent from grand master clock 1a, which uses an E2E profile, so the profile of packets transmitted and received at a port of communication device 100a connected to grand master clock 1a is determined to be the E2E profile.

[0088] As will be described later, a Pdelay_Req message is sent from client device 2b, which uses a P2P profile, and therefore the profile of packets transmitted and received at a port of communication device 100c connected to client device 2b is determined to be the P2P profile. Also, a Pdelay_Resp message is sent from grand master clock 1b, which uses a P2P profile, and therefore the profile of packets transmitted and received at a port of communication device 100a connected to grand master clock 1b is determined to be the P2P profile.

[0089] At time T3, the client device 2a transmits a Delay_Req message to the communication device 100c. The client device 2a periodically transmits the Delay_Req message.

[0090] At time dt7, the communication device 100c receives a Delay_Req message sent from the client device 2a. As described above, the profile of the packets sent and received via the single port connected to the client device 2a is determined to be an E2E profile. The communication device 100c stores the profile determination result (E2E) and the domainNumber and sourcePortIdentity included in the Delay_Req message. The sourcePortIdentity indicates the sender of the message (Delay_Req message). The sender of the Delay_Req message is the client device 2a. Therefore, the communication device 100c stores the profile determination result (E2E), the domainNumber, and the sourcePortIdentity (client device 2a) in association with each other.

[0091] At time dt8, communication device 100c transmits the received Delay_Req message to communication device 100b. Here, since the Delay_Req message is a message used in the E2E system, communication device 100c transmits the Delay_Req message to communication device 100b via a logical port corresponding to the E2E system that is set in the port (common port) on the upper device side of communication device 100c. Communication device 100c stores the reception time dt7 of the Delay_Req message from Client device 2a and the transmission time dt8 of the Delay_Req message to communication device 100b.

[0092] At time dt9, communication device 100b receives the Delay_Req message transmitted from communication device 100c. Because the Delay_Req message is a message used in the profile of the E2E system, communication device 100b determines that the profile of the message transmitted from communication device 100c is the E2E system profile. Based on the profile determination result, communication device 100b receives the Delay_Req message via a logical port corresponding to the E2E system that is set as a port (common port) on the lower device side.

[0093] The communication device 100b stores the profile determination result (E2E) in association with the domainNumber and sourcePortIdentity (Client device 2a) included in the Delay_Req message.

[0094] At time dt10, communication device 100b transmits the received Delay_Req message to communication device 100a. Here, since the Delay_Req message is a message used in the E2E system, communication device 100b transmits the Delay_Req message to communication device 100a via a logical port corresponding to the E2E system that is set in the port (common port) on the higher-level device side of communication device 100b. Communication device 100b stores the reception time dt9 of the Delay_Req message from communication device 100c and the transmission time dt10 of the Delay_Req message to communication device 100a.

[0095] At time dt11, the communication device 100a receives a Delay_Req message transmitted from the communication device 100b. Because the Delay_Req message is a message used in a profile for the E2E system, the communication device 100a determines that the profile of the message transmitted from the communication device 100b is the E2E system profile. Based on the profile determination result, the communication device 100a receives the Delay_Req message via a logical port corresponding to the E2E system that is set as a port (common port) on the lower device side.

[0096] The communication device 100a stores the profile determination result (E2E) in association with the domainNumber and sourcePortIdentity (Client device 2a) included in the Delay_Req message.

[0097] As described above, the profile of the packets transmitted and received via the single port connected to the Grand Master Clock 1a is determined to be an E2E profile. Therefore, at time dt12, the communication device 100a transmits the received Delay_Req message to the Grand Master Clock 1a via the port connected to the Grand Master Clock 1a. The communication device 100a stores the reception time dt11 of the Delay_Req message from the communication device 100b and the transmission time dt12 of the Delay_Req message to the Grand Master Clock 1a.

[0098] The Grand Master Clock 1a receives the Delay_Req message at time T4 and stores the time T4 at which the Grand Master Clock 1a receives the Delay_Req message.

[0099] Upon receiving the Delay_Req message, the Grand Master Clock 1a transmits a Delay_Resp message to the communication device 100a. The Grand Master Clock 1a includes the reception time T4 of the Delay_Req message in the Delay_Resp message.

[0100] The communication device 100a receives a Delay_Resp message via a port connected to the Grand Master Clock 1. The Delay_Resp message includes a domainNumber, a sourcePortIdentity, and a requestingPortIdentity. The sourcePortIdentity included in the Delay_Resp message indicates the Grand Master Clock 1a that is the sender of the Delay_Resp message, and the requestingPortIdentity included in the Delay_Resp message indicates the Client device 2a that is the destination of the Delay_Resp message. If the domainNumber and requestingPortIdentity (Client device 2a) included in the Delay_Resp message match the stored domainNumber and sourcePortIdentity (Client device 2a), the communication device 100a further associates and stores the sourcePortIdentity (Grand Master Clock 1a) included in the Delay_Resp message.

[0101] When the communication device 100a receives the Delay_Resp message, it transmits the received Delay_Resp message to the communication device 100b. Because the Delay_Resp message is a message used in the profile of the E2E method, the communication device 100a transmits the Delay_Resp message via a logical port corresponding to the E2E method that is set in the port (common port) on the lower device side. The communication device 100a sets a value corresponding to the E2E method in the CF of the Delay_Resp message. Specifically, the communication device 100a sets the processing time D6 (= dt12 - dt11) of the Delay_Req message in the communication device 100a in the CF of the Delay_Resp message.

[0102] The communication device 100b receives the Delay_Resp message transmitted from the communication device 100a. Because the Delay_Resp message is a message used in the profile of the E2E system, the communication device 100b determines that the profile of the message transmitted from the communication device 100a is the profile of the E2E system. Based on the profile determination result, the communication device 100b receives the Delay_Resp message via a logical port corresponding to the E2E system that is set as a port (common port) on the upper device side.

[0103] As described above, the Delay_Resp message includes the domainNumber, sourcePortIdentity (Grand Master Clock 1a), and requestingPortIdentity (Client device 2a). If the domainNumber and requestingPortIdentity (Client device 2a) included in the Delay_Resp message match the stored domainNumber and sourcePortIdentity (Client device 2a), the communication device 100b further associates and stores the sourcePortIdentity (Grand Master Clock 1a) included in the Delay_Resp message. In other words, the communication device 100b associates and stores the packet profile determination result (E2E), domainNumber, sourcePortIdentity (Client device 2a), and sourcePortIdentity (Grand Master Clock 1a).

[0104] Upon receiving the Delay_Resp message, the communication device 100b transmits the received Delay_Resp message to the communication device 100c. Because the Delay_Resp message is a message used in the profile of the E2E method, the communication device 100b transmits the Delay_Resp message via a logical port corresponding to the E2E method that is set in the port (common port) on the lower device side. The communication device 100b sets a value corresponding to the E2E method in the CF of the Delay_Resp message. Specifically, the communication device 100b sets the CF of the Delay_Resp message to a value (=D6+D5) obtained by adding the value (=D6) set in the CF of the received Delay_Resp message to the processing time D5 (=dt10-dt9) of the Delay_Req message in the communication device 100b.

[0105] The communication device 100c receives the Delay_Resp message transmitted from the communication device 100b. Since the Delay_Resp message is a message used in the profile of the E2E system, the communication device 100c determines that the profile of the message transmitted from the communication device 100b is the profile of the E2E system. Based on the profile determination result, the communication device 100c receives the Delay_Resp message via a logical port corresponding to the E2E system that is set in the port (common port) on the upper device side.

[0106] As described above, the Delay_Resp message includes the domainNumber, sourcePortIdentity (Grand Master Clock 1a), and requestingPortIdentity (Client device 2a). If the domainNumber and requestingPortIdentity (Client device 2a) included in the Delay_Resp message match the stored domainNumber and sourcePortIdentity (Client device 2a), the communication device 100c further associates and stores the sourcePortIdentity (Grand Master Clock 1a) included in the Delay_Resp message. In other words, the communication device 100c associates and stores the packet profile determination result (E2E), domainNumber, sourcePortIdentity (Client device 2a), and sourcePortIdentity (Grand Master Clock 1a).

[0107] Upon receiving the Delay_Resp message, the communication device 100c transmits the received Delay_Resp message to the client device 2a. Because the Delay_Resp message is a message used in the profile of the E2E system, the communication device 100c transmits the Delay_Resp message to the client device 2a via a port connected to the client device 2a, which has been determined to transmit and receive packets in accordance with the profile of the E2E system. The communication device 100c sets a value corresponding to the E2E system in the CF of the Delay_Resp message. Specifically, the communication device 100c sets the CF of the Delay_Resp message to a value (= D6 + D5 + D4) obtained by adding the value (= D6 + D5) set in the CF of the received Delay_Resp message to the processing time D4 (= dt8 - dt7) of the Delay_Req message in the communication device 100c.

[0108] The client device 2a receives the Delay_Resp message sent from the communication device 100c.

[0109] The Grand Master Clock 1a transmits a Sync message to the communication device 100a at time T1 after transmitting the Delay_Resp message. After transmitting the Sync message, the Grand Master Clock 1a transmits a Follow_Up message to the communication device 100a. The Grand Master Clock 1a includes the transmission time T1 of the Sync message in the Follow_Up message.

[0110] At time dt1, the communication device 100a receives a Sync message transmitted from the Grand Master Clock 1a. The communication device 100a also receives a Follow_Up message transmitted from the Grand Master Clock 1a. The Sync message and the Follow_Up message include a domain number and a source port identity (Grand Master Clock 1a). As described above, by transmitting and receiving the Delay_Req message and the Delay_Resp message, the communication device 100a associates and stores the profile determination result (E2E) of the packet transmitted and received via the port connected to the Grand Master Clock 1a with the domain number, the source port identity (Client device 2a), and the source port identity (Grand Master Clock 1a). The communication device 100a refers to the stored correspondence relationship and determines to transmit the Sync message and Follow_Up message as E2E messages based on the profile determined by the domainNumber and sourcePortIdentity (Grand Master Clock 1a) contained in the Sync message and Follow_Up message.

[0111] In accordance with the determination, at time dt2, the communication device 100a transmits a Sync message and a Follow_Up message to the communication device 100b via a logical port corresponding to the E2E method that is set as the port (common port) on the lower device side. The communication device 100a sets values ​​corresponding to the E2E method in the CF of the Sync message and the Follow_Up message. Specifically, 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.

[0112] At time dt3, communication device 100b receives the Sync message transmitted from communication device 100a. Communication device 100b also receives the Follow_Up message transmitted from communication device 100a. Communication device 100b stores the profile determination result (E2E), domain number, source port identity (client device 2a), and source port identity (grand master clock 1a) in association with each other. Communication device 100b references the stored associations and determines to transmit and receive the Sync message and Follow_Up message as E2E messages based on the profile determination result associated with the domain number and source port identity (grand master clock 1a) included in the Sync message and Follow_Up message.

[0113] Therefore, the communication device 100b receives the Sync message and the Follow_Up message via a logical port corresponding to the E2E method that is set as a port (common port) on the upper device side. Furthermore, in accordance with the decision, the communication device 100b transmits the Sync message and the Follow_Up message to the communication device 100c at time dt4 via a logical port corresponding to the E2E method that is set as a port (common port) on the lower device side. The communication device 100b sets values ​​corresponding to the E2E method in the CF of the Sync message and the Follow_Up message. Specifically, the communication device 100b sets the CF of the Follow_Up message to a value (= D1 + D2) obtained by adding the value (= D1) set in the CF of the received Follow_Up message to the processing time D2 (= dt4 - dt3) of the Sync message in the communication device 100b.

[0114] At time dt5, communication device 100c receives a Sync message transmitted from communication device 100b. Communication device 100c also receives a Follow_Up message transmitted from communication device 100b. Communication device 100c stores a profile determination result (E2E), a domain number, a source port identity (client device 2a), and a source port identity (grand master clock 1a) in association with each other. Communication device 100c references the stored associations and, based on the profile determination result associated with the domain number and source port identity (grand master clock 1a) included in the Sync message and the Follow_Up message, determines to transmit and receive the Sync message and the Follow_Up message as E2E messages.

[0115] Therefore, the communication device 100c receives the Sync message and the Follow_Up message via a logical port corresponding to the E2E method, which is set as a port (common port) on the higher-level device side. Furthermore, in accordance with the determination, the communication device 100c transmits the Sync message and the Follow_Up message to the client device 2a at time dt6 via a port connected to the client device 2a, which has been determined to transmit and receive packets with a profile using the E2E method. The communication device 100c sets values ​​corresponding to the E2E method in the CF of the Sync message and the Follow_Up message. Specifically, the communication device 100c sets the CF of the Follow_Up message to a value (= D1 + D2 + D3) obtained by adding the value (= D1 + D2) set in the CF of the received Follow_Up message to the processing time D3 (= dt6 - dt5) for the Sync message in the communication device 100c.

[0116] At time T2, the client device 2a receives the Sync message sent from the communication device 100c, and also receives the Follow_Up message sent from the communication device 100c. The client device 2a calculates an offset, which is the difference between the device time of the Grand Master Clock 1a and the device time of the client device 2a, using the following formula (5): the time T1 when the Sync message was sent by the Grand Master Clock 1a, the time T2 when the Sync message was received by the client device 2a, the time T3 when the Delay_Req message was sent by the client device 2a, the time T4 when the Delay_Req message was received by the Grand Master Clock 1a, which is included in the Delay_Resp message, the processing time (= D1 + D2 + D3) for the Sync message in the communication devices 100a, 100b, and 100c set in the CF of the Follow_Up message, and the processing time (= D6 + D5 + D4) for the Delay_Resp message in the communication devices 100a, 100b, and 100c set in the CF of the Delay_Resp message. The client device 2a can synchronize its internal time with the internal time of the Grand Master Clock 1a by correcting the internal time based on the calculated offset. Offset=((T2-T1-(D1+D2+D3))-(T4-T3-(D6+D5+D4))) / 2 Equation (5)

[0117] Next, the operation when synchronizing time between a Grand Master Clock 1b and a Client device 2b using a P2P profile will be described with reference to Fig. 3. Note that the determination of whether the port provided in the communication device 100 is a common port or a single port is the same as in Fig. 2, and therefore the description will be omitted.

[0118] At time t13, the client device 2b transmits a Pdelay_Req message to the communication device 100c. The client device 2b periodically transmits the Pdelay_Req message. The client device 2b stores the time t13 when the Pdelay_Req message was transmitted.

[0119] At time dt14, the communication device 100c receives a Pdelay_Req message from the client device 2b. As described above, the profile of the packets transmitted and received via the port connected to the client device 2b is determined to be a P2P profile. The communication device 100c stores the profile determination result (P2P) and the domainNumber and sourcePortIdentity (client device 2b) included in the Pdelay_Req message.

[0120] Upon receiving the Pdelay_Req message, the communication device 100c transmits a Pdelay_Resp message to the client device 2b via the port connected to the client device 2b at time dt15. The communication device 100c includes the reception time dt14 of the Pdelay_Req message in the Pdelay_Resp message. The communication device 100c stores the transmission time dt15 of the Pdelay_Resp message to the client device 2b.

[0121] After transmitting the Pdelay_Resp message, the communication device 100c transmits a Pdelay_Resp_Follow_Up message to the client device 2b via a port connected to the client device 2b. The communication device 100c includes a transmission time t15 of the Pdelay_Resp message to the client device 2b in the Pdelay_Resp_Follow_Up message.

[0122] At time t16, client device 2b receives the Pdelay_Resp message transmitted from communication device 100c. Client device 2b stores the reception time t16 of the Pdelay_Resp message. Client device 2b also receives the Pdelay_Resp_Follow_Up message transmitted from communication device 100c. Client device 2b calculates a transmission delay time pt4 between communication device 100c and client device 2b using the following equation (6) based on the transmission time t13 of the Pdelay_Req message by client device 2b, the reception time t14 of the Pdelay_Req message by communication device 100c which is included in the Pdelay_Resp message, the transmission time t15 of the Pdelay_Resp message by communication device 100c which is included in the Pdelay_Resp_Follow_Up message, and the reception time t16 of the Pdelay_Resp message by client device 2b. pt4=((t14-t13)+(t16-15)) / 2 Formula (6)

[0123] Furthermore, upon receiving the Pdelay_Req message from client device 2b, communication device 100c transmits the Pdelay_Req message to communication device 100b at time t9. Since the Pdelay_Req message is used in a P2P profile, communication device 100c transmits the Pdelay_Req message via a logical port corresponding to the P2P protocol that is set as a port (common port) on the higher-level device side. Communication device 100c stores the transmission time t9 of the Pdelay_Req message.

[0124] The communication device 100c stores the profile determination result (P2P) in association with the domainNumber and sourcePortIdentity (Client device 2b) included in the Pdelay_Req message.

[0125] At time t10, communication device 100b receives a Pdelay_Req message transmitted from communication device 100c. Because the Pdelay_Req message is a message used in a P2P profile, communication device 100b determines that the profile of the message transmitted from communication device 100c is a P2P profile. Based on the profile determination result, communication device 100b receives the Pdelay_Req message via a logical port corresponding to the P2P method that is set as a port (common port) on the lower device side. Communication device 100b stores the time t10 when the Pdelay_Req message was received.

[0126] Because the Pdelay_Req message received by communication device 100b was sent by communication device 100c, the sourcePortIdentity of the Pdelay_Req message indicates communication device 100c. Therefore, communication device 100b stores the profile determination result (P2P) and the domainNumber and sourcePortIdentity (communication device 100c) included in the Pdelay_Req message in association with each other.

[0127] Upon receiving the Pdelay_Req message, communication device 100b transmits a Pdelay_Resp message to communication device 100c at time t11. Because the Pdelay_Resp message is used in a P2P profile, communication device 100b transmits the Pdelay_Resp message via a logical port corresponding to the P2P protocol that is set as a port (common port) on the lower device side. Communication device 100b includes the reception time t10 of the Pdelay_Req message in the Pdelay_Resp message. Communication device 100b stores the transmission time t11 of the Pdelay_Resp message to communication device 100c.

[0128] After transmitting the Pdelay_Resp message, communication device 100b transmits a Pdelay_Resp_Follow_Up message to communication device 100c. Because the Pdelay_Resp_Follow_Up message is used in a P2P profile, communication device 100b transmits the Pdelay_Resp_Follow_Up message via a logical port corresponding to the P2P protocol that is set as a port (common port) on the lower device side. Communication device 100b includes the transmission time t11 of the Pdelay_Resp message to communication device 100c in the Pdelay_Resp_Follow_Up message.

[0129] At time t12, the communication device 100c receives the Pdelay_Resp message transmitted from the communication device 100b. The communication device 100c stores the reception time t12 of the Pdelay_Resp message. The communication device 100c also receives the Pdelay_Resp_Follow_Up message transmitted from the communication device 100b. The communication device 100c calculates the transmission delay time pt3 between the communication device 100b and the communication device 100c using the following equation (7) based on the transmission time t9 of the Pdelay_Req message by the communication device 100c, the reception time t10 of the Pdelay_Req message by the communication device 100b, which is included in the Pdelay_Resp message, the transmission time t11 of the Pdelay_Resp message by the communication device 100b, which is included in the Pdelay_Resp_Follow_Up message, and the reception time t12 of the Pdelay_Resp message by the communication device 100c. pt3=((t10-t9)+(t12-t11)) / 2 Formula (7)

[0130] Furthermore, upon receiving the Pdelay_Req message from communication device 100c, communication device 100b transmits the Pdelay_Req message to communication device 100a at time t5. Because the Pdelay_Req message is used in a P2P profile, communication device 100b transmits the Pdelay_Req message via a logical port corresponding to the P2P protocol that is set as a port (common port) on the higher-level device side. Communication device 100b stores the transmission time t5 of the Pdelay_Req message.

[0131] At time t6, communication device 100a receives a Pdelay_Req message transmitted from communication device 100b. Because the Pdelay_Req message is a message used in a P2P profile, communication device 100a determines that the profile of the message transmitted from communication device 100b is a P2P profile. Based on the profile determination result, communication device 100a receives the Pdelay_Req message via a logical port corresponding to the P2P method that is set as a port (common port) on the lower device side. Communication device 100a stores the time t6 when the Pdelay_Req message was received.

[0132] Because the Pdelay_Req message received by the communication device 100a was sent by the communication device 100b, the sourcePortIdentity of the Pdelay_Req message indicates the communication device 100b. Therefore, the communication device 100a stores the profile determination result (P2P) and the domainNumber and sourcePortIdentity (communication device 100b) included in the Pdelay_Req message in association with each other.

[0133] Upon receiving the Pdelay_Req message, the communication device 100a transmits a Pdelay_Resp message to the communication device 100b at time t7. Because the Pdelay_Resp message is used in a P2P profile, the communication device 100a transmits the Pdelay_Resp message via a logical port corresponding to the P2P protocol that is set as a port (common port) on the lower device side. 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.

[0134] After transmitting the Pdelay_Resp message, the communication device 100a transmits a Pdelay_Resp_Follow_Up message to the communication device 100b. Because the Pdelay_Resp_Follow_Up message is used in a profile for the P2P system, the communication device 100a transmits the Pdelay_Resp_Follow_Up message via a logical port corresponding to the P2P system that is set as a port (common port) on the lower device side. The communication device 100a includes the transmission time t7 of the Pdelay_Resp message to the communication device 100b in the Pdelay_Resp_Follow_Up message.

[0135] 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 transmitted from communication device 100a. 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 (8): pt2=((t6-t5)+(t8-t7)) / 2 Formula (8)

[0136] Furthermore, upon receiving a Pdelay_Req message from communication device 100b, communication device 100a transmits the Pdelay_Req message to Grand Master Clock 1b at time t1. Because the Pdelay_Req message is a message used in a P2P profile, communication device 100a transmits the Pdelay_Req message to Grand Master Clock 1b via a port connected to Grand Master Clock 1b, which port is determined to transmit and receive P2P packets. Communication device 100a stores the transmission time t1 of the Pdelay_Req message.

[0137] At time t2, the Grand Master Clock 1b receives the Pdelay_Req message transmitted from the communication device 100a and stores the time t2 at which the Pdelay_Req message was received.

[0138] Upon receiving the Pdelay_Req message, the Grand Master Clock 1b transmits a Pdelay_Resp message to the communication device 100a at time t3. The Grand Master Clock 1b includes the reception time t2 of the Pdelay_Req message in the Pdelay_Resp message. The Grand Master Clock 1b stores the transmission time t3 of the Pdelay_Resp message to the communication device 100a.

[0139] After transmitting the Pdelay_Resp message, the Grand Master Clock 1b transmits a Pdelay_Resp_Follow_Up message to the communication device 100a. The Grand Master Clock 1b includes the transmission time t3 of the Pdelay_Resp message to the communication device 100a in the Pdelay_Resp_Follow_Up message.

[0140] At time t4, the communication device 100a receives a Pdelay_Resp message transmitted from Grand Master Clock 1b via a port connected to Grand Master Clock 1b. The communication device 100a stores the time t4 at which the Pdelay_Resp message was received. The communication device 100a also receives a Pdelay_Resp_Follow_Up message transmitted from Grand Master Clock 1b. The communication device 100a calculates the transmission delay time pt1 between the Grand Master Clock 1b and the communication device 100a using the following equation (9): pt1=((t2-t1)+(t4-t3)) / 2 Equation (9) based on the time t1 when the communication device 100a transmits the Pdelay_Req message, the time t2 when the Grand Master Clock 1b receives the Pdelay_Req message contained in the Pdelay_Resp message, the time t3 when the Grand Master Clock 1b transmits the Pdelay_Resp message contained in the Pdelay_Resp_Follow_Up message, and the time t4 when the communication device 100a receives the Pdelay_Resp message.

[0141] The Grand Master Clock 1b transmits a Sync message to the communication device 100a at time T5 after transmitting the Pdelay_Resp message. After transmitting the Sync message, the Grand Master Clock 1b transmits a Follow_Up message to the communication device 100a. The Grand Master Clock 1b includes the transmission time T5 of the Sync message in the Follow_Up message.

[0142] At time dt13, the communication device 100a receives a Sync message transmitted from Grand Master Clock 1b via the port connected to Grand Master Clock 1b. The communication device 100a also receives a Follow_Up message transmitted from Grand Master Clock 1a. The Sync message and Follow_Up message include a domain number and a source port identity (Grand Master Clock 1b). As described above, by transmitting and receiving the Pdelay_Req message and the Pdelay_Resp message, the communication device 100a stores a profile determination result (P2P) for packets transmitted and received via the port connected to Grand Master Clock 1b, a domain number, and a source port identity (communication device 100b) in association with each other. The communication device 100a references the stored association and determines to process the Sync message and Follow_Up message as P2P messages based on the profile determination result associated with the domain number included in the Sync message and Follow_Up message.

[0143] In accordance with the determination, at time dt14, the communication device 100a transmits a Sync message and a Follow_Up message to the communication device 100b via a logical port corresponding to the P2P method that is set as the port (common port) on the lower device side. The communication device 100a sets values ​​corresponding to the P2P method in the CF of the Sync message and the Follow_Up message. Specifically, the communication device 100a sets the CF of the Follow_Up message to a value obtained by adding the transmission delay time pt1 between the Grand Master Clock 1b and the communication device 100a and the processing time D7 (= dt14 - dt13) of the Sync message in the communication device 100a.

[0144] At time dt15, communication device 100b receives the Sync message transmitted from communication device 100a. Communication device 100b also receives the Follow_Up message transmitted from communication device 100a. Communication device 100b stores the profile determination result (P2P), domain number, and sourcePortIdentity (communication device 100c) in association with each other. Communication device 100b references the stored association and, based on the profile determination result associated with domain number included in the Sync message and Follow_Up message, determines to process the Sync message and Follow_Up message as P2P messages.

[0145] Therefore, communication device 100b receives the Sync message and the Follow_Up message via a logical port corresponding to the P2P method that is set as a port (common port) on the upper device side. Furthermore, in accordance with the decision, communication device 100b transmits the Sync message and the Follow_Up message to communication device 100c at time dt16 via a logical port corresponding to the P2P method that is set as a port (common port) on the lower device side. Communication device 100b sets values ​​corresponding to the P2P method in the CF of the Sync message and the Follow_Up message. Specifically, communication device 100b sets the CF of the Follow_Up message to the value (=pt1+D7) set in the CF of the received Follow_Up message plus the transmission delay time pt2 between communication device 100a and communication device 100b and the processing time D8 (=dt16-dt15) of the Sync message in communication device 100b (=pt1+D7+pt2+D8).

[0146] At time dt17, communication device 100c receives a Sync message transmitted from communication device 100b. Communication device 100c also receives a Follow_Up message transmitted from communication device 100b. Communication device 100c stores the profile determination result (P2P), domain number, and source port identity (Client device 2b) in association with each other. Communication device 100c references the stored association and determines to process the Sync message and Follow_Up message as P2P messages based on the profile determination result associated with domain number included in the Sync message and Follow_Up message.

[0147] Therefore, the communication device 100c receives the Sync message and the Follow_Up message via a logical port corresponding to the P2P method that is set as a port (common port) on the higher-level device side. Furthermore, in accordance with the determination, the communication device 100c transmits the Sync message and the Follow_Up message to the client device 2b at time dt18 via the port connected to the client device 2b. The communication device 100c sets values ​​corresponding to the P2P method in the CF of the Sync message and the Follow_Up message. Specifically, communication device 100c sets the CF of the Follow_Up message to the value (=pt1+D7+pt2+D8+pt3+D9) obtained by adding the transmission delay time pt3 between communication device 100b and communication device 100c and the processing time D9 (=dt18-dt17) of the Sync message in communication device 100c to the value (=pt1+D7+pt2+D8+pt3+D9) set in the CF of the received Follow_Up message.

[0148] At time T6, client device 2b receives the Sync message transmitted from communication device 100c. Client device 2a also receives the Follow_Up message transmitted from communication device 100c. Client device 2b calculates the reception time T6 of the Sync message at the client device using the following formula (10): T6=T5+pt1+D7+pt2+D8+pt3+D9+pt4 (Formula (10)). This is based on the transmission time T5 of the Sync message by Grand Master Clock 1b, which is included in the Follow_Up message, the processing times D7, D8, and D9 of the Sync message at communication devices 100a, 100b, and 100c, and the transmission delay times pt1, pt2, and p3 between the devices, which are set in the CF of the Follow_Up message, and the transmission delay time pt4 between communication device 100c and client device 2b.

[0149] The client device 2b synchronizes its internal time with the calculated reception time T6 of the Sync message, thereby synchronizing the internal time of the client device 2b with the internal time of the Grand Master Clock 1b.

[0150] Next, the configuration of the communication device 100 will be described.

[0151] FIG. 4 is a diagram showing an example of the configuration of a communication device 100 according to this embodiment.

[0152] As shown in FIG. 4, the communication device 100 according to this embodiment includes packet transmitting / receiving units 101 and 102, a port determination unit 103, an E2E / P2P determination unit 104, a database creation unit 105, a packet processing determination unit 106, E2E logical port units 107 and 109, P2P logical port units 108 and 110, E2E processing units 111 and 113, and P2P processing units 112 and 114.

[0153] The packet transmitter / receiver 101 transmits and receives packets (PTP packets) to and from higher-level devices. When the communication device 100 is the communication device 100a, the packet transmitter / receiver 101 transmits and receives packets to and from the Grand Master Clocks 1a and 1b individually via ports (single ports) not shown in FIG. 4 . When the communication device 100 is the communication device 100b, the packet transmitter / receiver 101 transmits and receives packets to and from the communication device 100a via a port (common port) not shown in FIG. 4 . When the communication device 100 is the communication device 100c, the packet transmitter / receiver 101 transmits and receives packets to and from the communication device 100b via a port (common port) not shown in FIG. 4 .

[0154] The packet transmitting / receiving unit 102 transmits and receives packets (PTP packets) to and from lower-level devices. When the communication device 100 is the communication device 100a, the packet transmitting / receiving unit 102 transmits and receives packets to and from the communication device 100b via a port (common port) not shown in FIG. 4 . When the communication device 100 is the communication device 100b, the packet transmitting / receiving unit 102 transmits and receives packets to and from the communication device 100c via a port (common port) not shown in FIG. 4 . When the communication device 100 is the communication device 100c, the packet transmitting / receiving unit 102 transmits and receives packets to and from each of the client devices 2a and 2b individually via a port (single port) not shown in FIG. 4 .

[0155] The packet transmitting / receiving units 101 and 102 transmit and receive packets in accordance with packet processing determined by a packet processing determining unit 106, which will be described later.

[0156] The port determination unit 103 determines whether a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices provided in the communication device 100 are each a common port or a single port.

[0157] For example, when the port determination unit 103 receives a message containing multiple domain numbers via a port, it determines that the port is a common port, and when it receives only messages containing the same domain number, it determines that the port is a single port.

[0158] Furthermore, for example, when the port determination unit 103 receives both packets used in the E2E profile (Delay_Req message, Delay_Resp message) and packets used in the P2P profile (Pdelay_Req message, Pdelay_Resp message) via a port, it determines that the port is a common port, and when it receives only packets used in one of the profiles, it determines that the port is a single port.

[0159] The E2E / P2P determination unit 104, which serves as a profile determination unit, determines the profile of a packet from multiple profiles (in this embodiment, an E2E profile and a P2P profile) based on information indicating the type of the packet contained in the packet received by the packet transmitting / receiving units 101 and 102. The header information of the Req message and the Resp message includes a messageType indicating the type of the message. The E2E / P2P determination unit 104 can determine the type of the received message based on the value of messageType. The E2E / P2P determination unit 104 outputs the determination result to the database unit 105.

[0160] The database creation unit 105 associates and stores the packet profile determination result (E2E) made by the E2E / P2P determination unit 104, the domain number included in the packet that indicates a group of time-synchronized devices, and an identifier that indicates the source of the packet transmitted and received according to the profile. For example, as described with reference to Fig. 2, the database creation unit 105 associates and stores the packet profile determination result (E2E), the domain number included in the packet, the source port identity included in the Delay_Req message that indicates the client device 2a that is the source of the Delay_Req message, and the source port identity included in the Delay_Resp message that indicates the grand master clock 1a that is the source of the Delay_Resp message. Furthermore, as described with reference to Fig. 3, the database creation unit 105 associates and stores the packet profile determination result (P2P), the domain number included in the packet, and the source port identity included in the Pdelay_Req message that indicates the source of the Pdelay_Req message.

[0161] The packet processing determination unit 106 determines packet processing for the upper and lower devices and instructs the packet transmission / reception units 101 and 102. For example, when transmitting and receiving a packet at a port determined to be a common port based on the correspondence stored in the database unit 105, the packet processing determination unit 106 determines, as packet processing, that the packet be transmitted and received via a logical port corresponding to the packet profile. Furthermore, when transmitting and receiving a packet at a port determined to be a single port, the packet processing determination unit 106 determines, as packet processing, that the packet be transmitted and received via a single port corresponding to the packet profile and that the packet be discarded at another single port based on the correspondence stored in the database unit 105. For example, when transmitting a packet of an E2E system profile from a port (single port) determined to transmit and receive packets of an E2E system profile, the packet processing determination unit 106 determines, as packet processing, that the packet be discarded at a port (single port) determined to transmit and receive packets of another profile.

[0162] Furthermore, for example, if the database unit 105 does not store a correspondence relationship, it is unclear whether the CF values ​​in the Sync message and Follow_Up message should be set according to the E2E method or the P2P method. In this case, even if the packet processing determination unit 106 receives a Sync message or a Follow_Up message, it does not forward the message to a lower-level device, but instead determines to discard the message within its own device as the packet processing. Furthermore, when a P2P profile is used, as described with reference to FIG. 9 , the Transparent Clock 4 periodically transmits a Pdelay_Req message. On the other hand, in this embodiment, the packet processing determination unit 106 determines to wait for the transmission of a Pdelay_Req message as the packet processing until the E2E / P2P determination unit 104 determines that the packet profile is a P2P profile.

[0163] The E2E logical port unit 107 is a logical port set in accordance with the E2E method when the port through which the packet transmitter / receiver unit 101 transmits and receives packets to and from a higher-level device is a common port. The E2E logical port unit 107 passes packets transmitted and received as packets of the E2E method profile between the packet transmitter / receiver unit 101 and the E2E processing unit 111 via the port determined to be a common port.

[0164] The P2P logical port unit 108 is a logical port set in accordance with the P2P method when the port through which the packet transmitter / receiver 101 transmits and receives packets to and from a higher-level device is a common port. The P2P logical port unit 108 passes packets transmitted and received as packets of a P2P method profile between the packet transmitter / receiver 101 and the P2P processing unit 112 via the port determined to be a common port.

[0165] The E2E logical port unit 109 is a logical port set in accordance with the E2E method when the port through which the packet transmitter / receiver unit 102 transmits and receives packets to and from a lower-level device is a common port. The E2E logical port unit 109 passes packets transmitted and received as packets of the E2E method profile between the packet transmitter / receiver unit 102 and the E2E processing unit 111 via the port determined to be a common port.

[0166] The P2P logical port unit 110 is a logical port set in accordance with the P2P method when the port through which the packet transmitter / receiver unit 102 transmits and receives packets to and from a lower-level device is a common port. The P2P logical port unit 110 passes packets transmitted and received as packets of a P2P method profile between the packet transmitter / receiver unit 102 and the P2P processing unit 112 via the port determined to be a common port.

[0167] The E2E processing unit 111 performs processing according to the E2E method on packets sent and received at ports determined to be common ports by the packet sending and receiving units 101 and 102, and outputs the packets to the packet sending and receiving units 101 and 102 via the E2E logical port units 107 and 109.

[0168] The P2P processing unit 112 processes packets sent and received through ports determined by the packet sending and receiving units 101 and 102 to be common ports in accordance with the P2P method, and outputs the packets to the packet sending and receiving units 101 and 102 via the P2P logical port units 108 and 110.

[0169] The E2E processing unit 113 performs processing according to the E2E method on packets sent and received at a port (a single port of the E2E method) that has been determined by the packet sending and receiving units 101 and 102 to send and receive only packets of the E2E method profile, and outputs the processed packets to the packet sending and receiving units 101 and 102.

[0170] The P2P processing unit 114 performs processing according to the P2P method on packets sent and received at a port (a single P2P method port) that has been determined by the packet sending and receiving units 101 and 102 to send and receive only packets of the P2P method profile, and outputs the processed packets to the packet sending and receiving units 101 and 102.

[0171] Next, a description will be given of the operation of the communication device 100 according to this embodiment. 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.

[0172] The port determination unit 103 determines whether the port (first port) for transmitting and receiving packets with one or more higher-level devices and the port (second port) for transmitting and receiving packets with one or more lower-level devices that the communication device 100 has are each a common port or a single port (step S11).

[0173] As described above, for example, when a message including multiple domain numbers is received via a port, the port determination unit 103 determines that the port is a common port, and when only messages including the same domain number are received, the port determination unit 103 determines that the port is a single port.Furthermore, for example, when both packets used in the E2E profile (Delay_Req message, Delay_Resp message) and packets used in the P2P profile (Pdelay_Req message, Pdelay_Resp message) are received via a port, the port determination unit 103 determines that the port is a common port, and when only packets used in either profile are received, the port determination unit 103 determines that the port is a single port.

[0174] The packet processing determination unit 106 determines packet processing for the upper and lower devices (step S12). The packet transmission / reception units 101 and 102 transmit and receive packets according to the determined packet processing (step S13). Here, when transmitting a packet from a port determined to be a common port, the packet processing determination unit 106 determines, as the packet processing, to transmit the packet via a logical port corresponding to the packet profile.

[0175] As described above, the communication device 100 according to this embodiment has a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices. At least one of the first and second ports is a common port for transmitting and receiving packets of multiple profiles with different transmission delay measurement methods, and a logical port corresponding to each of the multiple profiles is set for the common port. The communication device 100 includes a port determination unit 103, a packet processing determination unit 106, and packet transmission / reception units 101 and 106. The port determination unit 103 determines whether the first and second ports are common ports or single ports. The packet processing determination unit 106 determines packet processing for the higher-level device and the lower-level device. The packet transmission / reception units 101 and 102 transmit and receive packets according to the determined packet processing. Here, when transmitting and receiving packets through a port determined to be a common port, the packet processing determination unit 106 determines packet processing to be performed via a logical port corresponding to the packet profile.

[0176] By transmitting and receiving packets of each of the multiple profiles via a logical port corresponding to each profile, it is possible to transmit and receive packets of the multiple profiles in a superimposed manner. This eliminates the need to prepare lines and ports for each of the multiple profiles. Therefore, the communication device 100 according to the present disclosure can transmit and receive packets (PTP packets) of different profiles while suppressing increases in costs.

[0177] Next, the hardware configuration of the communication device 100 according to the present disclosure will be described.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] The input unit 205 includes a pointing device such as a mouse and a keyboard, and is used to input various types of information.

[0184] 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.

[0185] The communication interface 207 is an interface for communicating with other devices (for example, the Grand Master Clock 1, the Client device 2).

[0186] 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.

[0187] The following additional notes are provided regarding the above-described embodiments.

[0188] [Supplementary Item 1] A communication device provided in multiple locations between a first device and a second device that are time-synchronized, and that transmits and receives packets for the time synchronization, the communication device having: a control unit; a first port for transmitting and receiving packets with one or more higher-level devices; and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port being a common port for transmitting and receiving packets of multiple profiles that have different methods of measuring transmission delay, and a logical port corresponding to each of the multiple profiles being set in the common port, the control unit being configured to: determine whether the first port and the second port are each the common port or a single port for transmitting and receiving packets of a single profile, determine packet processing for the higher-level device and the lower-level device, and transmit and receive packets in accordance with the determined packet processing,

[0189] [Supplementary Item 2] In the communications device described in Supplementary Item 1, the control unit determines a profile of the packet from the plurality of profiles based on information included in the received packet that indicates the type of the packet; records the determination result of the profile of the packet, a domainNumber that indicates a group of time-synchronized devices included in the packet, and an identifier that indicates the source of the packet transmitted and received according to the profile, in association with each other; when transmitting and receiving a packet at a port determined to be the common port, determines, based on the recorded association, that the packet processing is to transmit and receive the packet via a logical port that corresponds to the profile of the packet; and when transmitting and receiving a packet at a port determined to be the single port, determines, based on the recorded association, that the packet processing is to transmit and receive the packet via a single port that corresponds to the profile of the packet and to discard the packet at another single port.

[0190] [Supplementary Item 3] A communications system comprising: a first device and a second device that perform time synchronization; and a plurality of communication devices that are provided between the first device and the second device and that transmit and receive packets for the time synchronization, wherein the communication devices have a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port is a common port that transmits and receives packets of a plurality of profiles that have different transmission delay measurement methods, and a logical port corresponding to each of the plurality of profiles is set for the common port, the system determines whether the first port and the second port are the common port or a single port that transmits and receives packets of a single profile, determines packet processing for the higher-level device and the lower-level device, transmits and receives packets in accordance with the determined packet processing, and when transmitting and receiving packets via a port determined to be the common port, determines that the packet processing will be the transmission and reception of the packet via the logical port corresponding to the profile of the packet.

[0191] [Supplementary Item 4] A communication method using a communication device provided in plurality between a first device and a second device that are time-synchronized, and that transmits and receives packets for the time synchronization, wherein the communication device has a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port is a common port for transmitting and receiving packets of multiple profiles that have different transmission delay measurement methods, and a logical port corresponding to each of the multiple profiles is set in the common port, the method determines whether the first port and the second port are the common port or a single port for transmitting and receiving packets of a single profile, determines packet processing for the higher-level device and the lower-level device, transmits and receives packets in accordance with the determined packet processing, and when transmitting and receiving packets via the port determined to be the common port, determines that the packet processing will be transmitting and receiving the packet via the logical port corresponding to the profile of the packet.

[0192] 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.

[0193] DESCRIPTION OF SYMBOLS 1, 1a, 1b Grand Master Clock (first device) 2, 2a, 2b Client device (second device) 3, 3a, 3b, 3c Boundary Clock 4, 4a, 4b, 4c Transparent Clock 10 Communication system 100, 100a, 100b, 100c Communication device 101, 102 Packet transmitting / receiving unit 103 Port determination unit 104 E2E / P2P determination unit (profile determination unit) 105 Database creation unit 106 Packet processing determination unit 107, 109 E2E logical port unit 108, 110 P2P logical port unit 111, 113 E2E processing unit 112, 114 P2P processing unit 201 Processor 202 ROM 203 RAM 204 Storage 205 Input unit 206 Display unit 207 Communication I / F 209 Bus

Claims

1. A communications device provided between a first device and a second device to be time-synchronized, and transmitting and receiving packets for the time synchronization, the communications device having a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port being a common port for transmitting and receiving packets of a plurality of profiles having different transmission delay measurement methods, a logical port corresponding to each of the plurality of profiles being set in the common port, the communications device comprising: a port determination unit that determines whether the first port and the second port are the common port or a single port for transmitting and receiving packets of a single profile; a packet processing determination unit that determines packet processing for the higher-level device and the lower-level device; and a packet transmission / reception unit that transmits and receives packets in accordance with the determined packet processing, wherein when a packet is transmitted or received through a port determined to be the common port, the packet processing determination unit determines that the packet processing will be the transmission and reception of the packet via the logical port corresponding to the profile of the packet.

2. A communications device as described in claim 1, further comprising: a profile determination unit which determines a profile of the packet from the multiple profiles based on information contained in a received packet that indicates the type of the packet; and a database creation unit which records the result of the profile determination of the packet, a domainNumber which indicates a group of time-synchronized devices contained in the packet, and an identifier which indicates the source of the packet transmitted and received according to the profile, in association with each other, wherein the packet processing determination unit, when transmitting and receiving a packet at a port determined to be the common port, determines, based on the recorded correspondence, that the packet processing is to transmit and receive the packet via a logical port corresponding to the profile of the packet; and, when transmitting and receiving a packet at a port determined to be the single port, determines, based on the recorded correspondence, that the packet processing is to transmit and receive the packet via a single port which corresponds to the profile of the packet, and to discard the packet at another single port.

3. A communications system comprising: a first device and a second device which perform time synchronization; and a plurality of communication devices which are provided between the first device and the second device and transmit and receive packets for the time synchronization, wherein the communication devices have a first port for transmitting and receiving packets with one or more upper devices and a second port for transmitting and receiving packets with one or more lower devices, at least one of the first port and the second port being a common port for transmitting and receiving packets of a plurality of profiles having different transmission delay measurement methods, wherein a logical port corresponding to each of the plurality of profiles is set in the common port, and the communications system comprises: a port determination unit which determines whether the first port and the second port are the common port or a single port for transmitting and receiving packets of a single profile; a packet processing determination unit which determines packet processing for the upper device and the lower device; and a packet transmission / reception unit which transmits and receives packets in accordance with the determined packet processing, wherein when a packet is transmitted or received through a port determined to be the common port, the packet processing determination unit determines that the packet processing is to transmit and receive the packet via a logical port corresponding to the profile of the packet.

4. A communication method by a communication device provided between a first device and a second device for time synchronization, the communication device having a first port for transmitting and receiving packets with one or more higher-level devices and a second port for transmitting and receiving packets with one or more lower-level devices, at least one of the first port and the second port being a common port for transmitting and receiving packets of a plurality of profiles having different transmission delay measurement methods, the common port being set with a logical port corresponding to each of the plurality of profiles, the communication method including the steps of: determining whether the first port and the second port are the common port or a single port for transmitting and receiving packets of a single profile; determining packet processing for the higher-level device and the lower-level device; and transmitting and receiving packets in accordance with the determined packet processing, wherein when a packet is transmitted or received via a port determined to be the common port, the transmission and reception of the packet via the logical port corresponding to the profile of the packet is determined as the packet processing.

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