Communication device, communication method, and communication program

Abstract

To provide a communication device, a communication system, a communication method, and a communication program that are capable of grasping the reception time and transmission time of a packet in a slave device.SOLUTION: A communication device that functions as a slave device that performs communication in accordance with the PTP communication protocol includes a reception time addition unit that adds reception time information indicating the time at which the slave device received a packet to the packet transmitted by a master device that performs communication in accordance with the PTP communication protocol, and a transmission unit that transmits the packet to which the reception time information has been added by the reception time addition unit.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present disclosure relates to a communication device, a communication system, a communication method, and a communication program for performing time synchronization among a plurality of communication devices. [Background technology]

[0002] As communication networks become faster, there is a demand for highly accurate time synchronization between multiple communication devices. One such high-accuracy time synchronization standard is the Precision Time Protocol (PTP), a communication protocol defined in IEEE1588-2008 and IEEE1588-2019. In PTP, time information in various packets (hereinafter referred to as "synchronization packets") that synchronize the time information of slave devices with the reference time information of the master device is used to synchronize the time between the master device and the slave device.

[0003] More specifically, in PTP, a slave device performs time synchronization using the transmission time and reception time of a synchronization packet from the master device. Therefore, the PTP synchronization packet includes the transmission time and reception time of the synchronization packet from the master device, but does not include the reception time (syncEventIngressTimeStamp: T2) and transmission time (deayReqEventEgressTimeStamp: T3) of the synchronization packet from the slave device. Therefore, the reception time T2 and transmission time T3 of the synchronization packet from the slave device cannot be confirmed without referencing the internal information of the slave device. In the event of a communication system failure, the communication system administrator must request the slave device vendor to analyze and disclose the internal information. This poses a problem in that the communication system administrator cannot quickly determine the reception time and transmission time of the synchronization packet from the slave device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-53750 Summary of the Invention [Problem to be solved by the invention]

[0005] In this regard, Patent Document 1 discloses a synchronization accuracy evaluation device that evaluates synchronization accuracy in an IP broadcasting system that uses PTP. However, the synchronization accuracy evaluation device disclosed in Patent Document 1 does not provide the reception time and transmission time of a synchronization packet in a slave device, and therefore cannot quickly ascertain the reception time and transmission time of the synchronization packet in the slave device.

[0006] In view of the above-mentioned problems, one of the objects of the present disclosure is to provide a communication device, a communication system, a communication method, and a communication program that are capable of determining the reception time and transmission time of a packet in a slave device. [Means for solving the problem]

[0007] A communication device that functions as a slave device that performs communication in accordance with the PTP communication protocol according to the present disclosure includes: a reception time adding unit that adds reception time information indicating the time at which a slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; The receiving unit includes a transmitting unit that transmits the packet to which the reception time information has been added by the reception time adding unit.

[0008] A communication device that functions as a slave device that performs communication in accordance with the PTP communication protocol according to the present disclosure includes: a transmitter that transmits a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; a transmission time acquisition unit that acquires transmission time information indicating the time when the transmission unit transmitted the request packet; a transmission time adding unit that adds the transmission time information acquired by the transmission time acquiring unit to the response packet when the response packet is received in response to the request packet; The device further includes a transmitting unit that transmits a response packet to which the transmission time information has been added by the transmission time adding unit.

[0009] A communication method executed by a communication device functioning as a slave device that performs communication in accordance with the PTP communication protocol according to the present disclosure includes: adding reception time information indicating the time at which a slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; and transmitting the packet to which the reception time information is added.

[0010] A communication method executed by a communication device functioning as a slave device that performs communication in accordance with the PTP communication protocol according to the present disclosure includes: transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which transmission time information has been added.

[0011] The communication program according to the present disclosure is for a communication device that functions as a slave device that performs communication in accordance with the PTP communication protocol, adding reception time information indicating the time at which a slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; and transmitting a packet to which the reception time information is added.

[0012] The communication program according to the present disclosure is for a communication device that functions as a slave device that performs communication in accordance with the PTP communication protocol, transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which transmission time information is added. [Effects of the Invention]

[0013] The present disclosure makes it possible to provide a communication device, a communication system, a communication method, and a communication program that are capable of ascertaining the reception time and transmission time of a packet in a slave device. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating an example of a communication system according to the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a slave device according to the present disclosure. [Figure 3] FIG. 10 is a diagram illustrating an example of the data structure of a PTP synchronization packet. [Figure 4] FIG. 10 is a diagram illustrating an example of a padding area of ​​a SYNC packet. [Figure 5] FIG. 10 is a diagram illustrating an example of a padding area of ​​a DELAY_RESP packet. [Figure 6] FIG. 10 is a sequence diagram illustrating an overview of an example of processing executed in a communication system according to the present disclosure. [Figure 7] FIG. 10 is a sequence diagram illustrating an overview of another example of processing executed in the communication system according to the present disclosure. [Figure 8] 10 is a flowchart illustrating an example of processing executed by a packet processing unit of a slave device according to the present disclosure. [Figure 9] 10 is a flowchart illustrating another example of processing executed by the control unit of the slave device according to the present disclosure. [Figure 10] 10 is a flowchart illustrating another example of processing executed by a packet processing unit of a slave device according to the present disclosure. [Figure 11]10 is a flowchart illustrating another example of processing executed by a packet processing unit of a slave device according to the present disclosure. [Figure 12] 10 is a flowchart illustrating another example of processing executed by the control unit of the slave device according to the present disclosure. [Figure 13] FIG. 2 is a diagram illustrating an example of main components of a slave device according to the present disclosure. [Figure 14] FIG. 10 is a diagram illustrating another example of main components of a slave device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] An exemplary embodiment will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing an example of a communication system 1 according to the present disclosure. The communication system 1 includes a slave device 10, a master device 20, and a packet capture device 30. The slave device 10, the master device 20, and the packet capture device 30 can transmit and receive data to and from each other via a network 40. The network 40 can be configured to include various relay devices 401, 402 such as optical couplers.

[0016] The slave device 10 is a communication device that exchanges various packets with the master device 20. A specific example of the slave device 10 is a communication device used in a base station. The slave device 10 will be described in detail later.

[0017] The master device 20 is a communication device that exchanges various packets with the slave device 10. A specific example of the master device 20 is a communication device used in a base station. The master device 20 transmits various packets used for time synchronization between the master device 20 and the slave device 10. The packets transmitted by the master device 20 include a SYNC packet and a DELAY_RESP packet, which are PTP synchronization packets. The SYNC packet is added with the transmission time at the master device 20. The DELAY_RESP packet is added with the reception time at the master device 20 of the DELAY_REQ packet. The DELAY_RESP packet is a packet for responding to a DELAY_REQ packet, which is a PTP synchronization packet transmitted by the slave device 10. The DELAY_REQ packet corresponds to a request packet. The DELAY_RESP corresponds to a response packet.

[0018] The packet capture device 30 is an information processing device that analyzes packets transmitted by the slave device 10. A specific example of the packet capture device 30 is a server. The packet capture device 30 can acquire packets flowing on a transmission path and packets to which time information has been added in the slave device 10. By linking the time information obtained from the packets to which time information has been added in the slave device 10 to the packets flowing on the transmission path, the packet capture device 30 can refer to the time information while maintaining the original packet order and the timing at which the packets passed through the transmission path.

[0019] 2 is a diagram showing an example of the configuration of the slave device 10 according to the present disclosure. The slave device 10 includes a control unit 100, a counter 110, and a packet processing unit 120.

[0020] The packet processing unit 120 is a means for processing packets received by the slave device 10 from the master device 20 and packets transmitted by the slave device 10 to the master device 20 and the packet capture device 30. The packet processing unit 120 can be implemented by an integrated circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). In other embodiments, the processing performed by the packet processing unit 120 may be performed by a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). These devices correspond to computers.

[0021] The packet processing unit 120 includes communication interfaces (I / F) 101 to 103, a packet forwarding unit 104, a packet forwarding unit 105, a reception time information acquisition and retention unit 106, a transmission time information acquisition and retention unit 107, a reception time addition unit 108, and a transmission time addition unit 109.

[0022] The communication interface 101 is an interface that receives packets transmitted by the master device 20. When the communication interface 101 receives a packet, it provides the packet to the packet forwarding unit 104 and also provides a notification signal that notifies the reception time information acquisition and retention unit 106 of the timing at which the packet was received from the master device 20. For example, the communication interface 101 can notify the timing at which the first frame of the packet passed through the communication interface 101.

[0023] The packet forwarding unit 104 is a means for forwarding a packet received from the master device 20 via the communication interface 101 depending on the type of the packet. Specifically, if the received packet is a SYNC packet, the packet forwarding unit 104 forwards the SYNC packet to the reception time adding unit 108. If the received packet is a DELAY_RESP packet, the packet forwarding unit 104 forwards the DELAY_RESP packet to the transmission time adding unit 109. If the received packet is a packet other than a SYNC packet or a DELAY_RESP packet, the packet forwarding unit 104 forwards the packet to the control unit 100.

[0024] The reception time information acquisition and retention unit 106 is a means for acquiring and retaining reception time information indicating the time at which the slave device 10 received a packet from the master device 20. Specifically, upon receiving a notification signal from the communication interface 101, the reception time information acquisition and retention unit 106 acquires and retains time information from the counter 110. This acquired time information corresponds to the reception time information. Furthermore, the reception time information acquisition and retention unit 106 discards the retained time information under the control of the reception time addition unit 108.

[0025] The reception time adding unit 108 is a means for adding reception time information to a packet received from the master device 20. Specifically, the reception time adding unit 108 acquires reception time information from the reception time information acquiring and retaining unit 106, adds the reception time information to the SYNC packet, and updates the frame check sequence (FCS) of the SYNC packet. FIG. 3 is a diagram showing an example of the data structure of a PTP synchronization packet. FIG. 4 is a diagram showing an example of the padding area of ​​a SYNC packet. As shown in FIG. 4, the reception time adding unit 108 can add reception time information indicating the reception time T2 to the padding area of ​​the SYNC packet. The reception time adding unit 108 transmits the updated SYNC packet, to which the reception time information has been added, to the control unit 100 and also to the packet capture device 30 via the communication interface 103.

[0026] Furthermore, when the reception time adding unit 108 acquires the reception time information from the reception time information acquiring and holding unit 106, it causes the reception time information acquiring and holding unit 106 to discard the reception time information held by the reception time information acquiring and holding unit 106.

[0027] The packet forwarding unit 105 is a means for forwarding a packet received from the control unit 100. Specifically, when the packet received from the control unit 100 is a DELAY_REQ packet, the packet forwarding unit 105 transmits the DELAY_REQ packet to the master device 20 and the packet capture device 30 via the communication interface 102, and notifies the transmission time information acquisition and retention unit 107 of the sequence ID included in the DELAY_REQ packet. This sequence ID is identification information for a series of processes (sequences) related to the DELAY_REQ packet.

[0028] The communication interface 102 is an interface that transmits packets received from the packet forwarding unit 105 to the master device 20 and the packet capturing device 30. The communication interface 102 corresponds to a transmitting unit. When the communication interface 102 receives a packet, it transmits the packet to the master device 20 and the packet capturing device 30, and also transmits a notification signal to the transmission time information acquiring and retaining unit 107 to notify the timing at which the packet was transmitted to the master device 20. For example, the communication interface 102 can notify the timing at which the first frame of the packet passed through the communication interface 102.

[0029] The transmission time information acquisition and retention unit 107 is a means for acquiring and retaining transmission time information indicating the time at which the slave device 10 transmitted a packet to the master device 20. The transmission time information acquisition and retention unit 107 corresponds to the transmission time acquisition unit. Specifically, upon receiving a notification signal from the communication interface 102, the transmission time information acquisition and retention unit 107 acquires and retains time information from the counter 110. This acquired time information corresponds to the transmission time information. Here, the transmission time information acquisition and retention unit 107 associates the transmission time information of the acquired DELAY_REQ packet with the sequence ID of the DELAY_REQ packet notified by the packet forwarding unit 105 and retains it. Furthermore, the transmission time information acquisition and retention unit 107 discards the retained time information and sequence ID under the control of the transmission time addition unit 109.

[0030] The transmission time adding unit 109 is a means for adding transmission time information of the DELAY_REQ packet to a packet that the slave device 10 transmits to the packet capture device 30. Specifically, the transmission time adding unit 109 acquires the transmission time information of the DELAY_REQ packet and the sequence ID associated with the transmission time information, i.e., the sequence ID of the DELAY_REQ packet, from the transmission time information acquiring and retaining unit 107. Next, the transmission time adding unit 109 determines whether the sequence ID of the DELAY_RESP packet from the master device 20 transferred by the packet transferring unit 104 matches the sequence ID of the DELAY_REQ packet acquired from the transmission time information acquiring and retaining unit 107. In other words, the transmission time adding unit 109 determines whether the DELAY_RESP packet received by the slave device 10 is a response to the previously transmitted DELAY_REQ packet.

[0031] If these sequence IDs match, in other words, if the DELAY_RESP packet received by the slave device 10 is a response to a previously transmitted DELAY_REQ packet, the transmission time adding unit 109 adds transmission time information to the DELAY_RESP packet and updates the frame check sequence of the DELAY_RESP packet. FIG. 5 is a diagram showing an example of the padding area of ​​a DELAY_RESP packet. As shown in FIG. 5, the transmission time adding unit 109 adds transmission time information indicating transmission time T3 to the padding area of ​​the DELAY_RESP packet. The transmission time adding unit 109 transmits the updated DELAY_RESP packet, to which the transmission time information has been added, to the packet capture device 30 via the communication interface 103.

[0032] In addition, when the transmission time addition unit 109 acquires the transmission time information and sequence ID from the transmission time information acquisition and retention unit 107, it causes the transmission time information acquisition and retention unit 107 to discard the transmission time information and sequence ID held by the transmission time information acquisition and retention unit 107.

[0033] The control unit 100 performs termination processing for transmitting and receiving packets. The control unit 100 also synchronizes the time information of the slave device 10 with the time information of the master device 20 using the acquired packets. More specifically, the control unit 100 detects a difference between the time information of the slave device 10 and the time information of the master device 20 based on a comparison of the reception time and transmission time of packets transmitted and received between the master device 20 and the slave device 10, and updates the counter 110 to correct the difference, thereby performing synchronization control. The control unit 100 can be implemented by a processor such as a CPU or MPU. In other embodiments, the processing performed by the control unit 100 may be performed by an integrated circuit such as an FPGA or ASIC. These devices correspond to computers.

[0034] The counter 110 is a device that supplies time information and a clock signal used within the slave device 10 to the reception time information acquisition and retention unit 106 and the transmission time information acquisition and retention unit 107 .

[0035] The communication interface 103 is an interface that transmits, to the packet capture device 30, an updated SYNC packet to which the reception time information of the SYNC packet received by the slave device 10 has been added, and an updated DELAY_RESP packet to which the transmission time information of the DELAY_REQ packet transmitted by the slave device 10 has been added. The communication interface 103 corresponds to a transmitting unit.

[0036] 6 is a sequence diagram showing an overview of an example of processing executed in the communication system 1. In step S1, the master device 20 transmits a SYNC packet to the slave device 10. When the slave device 10 receives the SYNC packet transmitted by the master device 20, in step S2, the packet processing unit 120 of the slave device 10 adds reception time information indicating the time at which the slave device 10 received the SYNC packet to the SYNC packet. In step S3, the packet processing unit 120 transmits the updated SYNC packet with the reception time information added to the control unit 100. In step S4, the packet processing unit 120 transmits the updated SYNC packet with the reception time information added to the packet capture device 30. In step S5, the control unit 100 determines the reception time T2 of the SYNC packet at the slave device 10.

[0037] 7 is a sequence diagram showing an outline of another example of processing executed in the communication system 1. In step S11, the control unit 100 of the slave device 10 transmits a DELAY_REQ packet to the packet processing unit 120. Upon receiving the DELAY_REQ packet, the packet processing unit 120 transmits the DELAY_REQ packet to the master device 20 and the packet capture device 30 in step S12. In step S13, the packet processing unit 120 obtains, from the counter 110, transmission time information indicating the time when the DELAY_REQ packet was transmitted to the master device 20, and also obtains a sequence ID from the DELAY_REQ packet.

[0038] When the master device 20 receives the DELAY_REQ packet transmitted by the slave device 10, in step S14 it transmits a DELAY_RESP packet in response to the DELAY_REQ packet to the slave device 10. When the slave device 10 receives the DELAY_RESP packet, in step S15 the packet processing unit 120 of the slave device 10 determines whether the sequence ID included in the DELAY_RESP packet matches the sequence ID of the DELAY_REQ acquired in step S13.

[0039] If these sequence IDs match, in step S16 the packet processing unit 120 adds the sending time information acquired in step S13 to the DELAY_RESP packet. In step S17, the packet processing unit 120 transmits the updated DELAY_RESP packet with the sending time information added to the control unit 100. In step S18, the packet processing unit 120 transmits the updated DELAY_RESP packet with the sending time information added to the packet capture device 30.

[0040] When control unit 100 receives a DELAY_RESP packet, in step S19 it determines whether the value of the transmission time information added to the DELAY_RESP packet is 0. If it is determined that the value of the transmission time information added to the DELAY_RESP packet is not 0, in step S20 control unit 100 determines the transmission time (deayReqEventEgressTimeStamp: T3) and the reception time (deayReqEventIngressTimeStamp: T4) of the DELAY_REQ packet based on the transmission time information and reception time information added to the DELAY_RESP packet. The reception time information indicating the reception time T4 is added to the DELAY_RESP packet by master device 20.

[0041] 8 is a flowchart showing an example of processing executed by the packet processing unit 120 of the slave device 10. In step S21, the packet processing unit 120 receives a SYNC packet from the master device 20. Upon receiving the SYNC packet from the master device 20, the packet processing unit 120 acquires time information from the counter 110 in step S22. The time indicated by this time information corresponds to the reception time T2 at which the slave device 10 received the SYNC packet.

[0042] In step S23, packet processing unit 120 adds reception time information, which is the acquired time information, to the SYNC packet. In step S24, packet processing unit 120 transmits the updated SYNC packet with the reception time information added to control unit 100. In step S25, packet processing unit 120 transmits the updated SYNC packet with the reception time information added to packet capture device 30, and the processing in FIG. 8 ends.

[0043] 9 is a flowchart showing another example of processing executed by the control unit 100 of the slave device 10. In step S31, the control unit 100 receives the SYNC packet transmitted by the packet processing unit 120. In step S32, the control unit 100 acquires a sequence ID from the received SYNC packet. This sequence ID is identification information for a series of processing steps related to the SYNC packet.

[0044] In step S33, the control unit 100 acquires reception time information from the received SYNC packet. In step S34, the control unit 100 determines the time indicated by the reception time information acquired from the SYNC packet as reception time T2 at which the slave device 10 received the SYNC packet, and the process in FIG. 9 ends.

[0045] 10 is a flowchart showing another example of processing executed by the packet processing unit 120 of the slave device 10. In step S41, the packet processing unit 120 receives a DELAY_REQ packet from the control unit 100. In step S42, the packet processing unit 120 acquires a sequence ID from the DELAY_REQ packet. This sequence ID is identification information for a series of processes related to the DELAY_REQ packet. Note that the sequence ID of the DELAY_REQ packet is different from the sequence ID of the SYNC packet described above.

[0046] In step S43, the packet processing unit 120 transmits the DELAY_REQ packet to the master device 20 and the packet capturing device 30. In step S44, the packet processing unit 120 acquires time information from the counter 110, and the processing in Fig. 10 ends. The time indicated by this time information corresponds to transmission time T3 when the slave device 10 transmitted the DELAY_REQ packet.

[0047] 11 is a flowchart showing another example of processing executed by the packet processing unit 120 of the slave device 10. In step S51, the packet processing unit 120 receives a DELAY_RESP packet from the master device 20. In step S52, the packet processing unit 120 acquires a sequence ID from the DELAY_RESP packet. This sequence ID is identification information for a series of processes related to the DELAY_RESP packet, and matches the sequence ID of the DELAY_REQ packet corresponding to the DELAY_RESP packet.

[0048] In step S53, the packet processing unit 120 determines whether the sequence ID acquired from the DELAY_RESP packet in step S52 matches the sequence ID acquired from the DELAY_REQ packet in step S42. In other words, the packet processing unit 120 determines whether the received DELAY_RESP packet is a response to the DELAY_REQ packet sent in step S43.

[0049] If it is determined that these sequence IDs match (YES), then in step S54 the packet processing unit 120 adds the time information acquired in step S44, that is, the transmission time information of the DELAY_REQ packet, to the DELAY_RESP packet.

[0050] On the other hand, if it is determined that these sequence IDs do not match (NO), the packet processing unit 120 adds transmission time information whose value is 0 to the DELAY_RESP packet in step S55.

[0051] In step S56, the packet processing unit 120 transmits the DELAY_RESP packet with the transmission time information added thereto to the control unit 100. In step S57, the packet processing unit 120 transmits the DELAY_RESP packet with the transmission time information added thereto to the packet capture device 30, and the processing in FIG. 11 ends.

[0052] 12 is a flowchart showing another example of processing executed by the control unit 100 of the slave device 10. In step S61, the control unit 100 receives a DELAY_RESP packet with transmission time information added from the packet processing unit 120. In step S62, the control unit 100 acquires transmission time information of the DELAY_REQ packet from the DELAY_RESP packet with the transmission time information added. In step S63, the control unit 100 acquires reception time information from the DELAY_RESP packet. This reception time information is information indicating the reception time T4 of the DELAY_REQ packet at the master device 20.

[0053] In step S64, the control unit 100 determines whether the value of the transmission time information acquired in step S62 is 0. If it is determined that the value of the transmission time information is not 0 (NO), in step S65 the control unit 100 determines the time indicated by the transmission time information acquired in step S62 as transmission time T3 and the time indicated by the reception time information acquired in step S63 as reception time T4, and the processing in Fig. 12 ends. In other words, if the DELAY_RESP packet received from the master device 20 is a response to the DELAY_REQ packet transmitted to the master device 20, the transmission time T3 and reception time T4 are determined in this manner.

[0054] On the other hand, if it is determined that the value of the transmission time information is 0 (YES), the control unit 100 discards the acquired transmission time information and reception time information in step S66, and the processing of FIG. 12 ends.

[0055] 13 is a diagram showing an example of the main components of the slave device 10. The slave device 10 includes a reception time adding unit 108 and a transmitting unit 103. Here, the transmitting unit 103 corresponds to the communication interface 103 in FIG. 2. The reception time adding unit 108 adds reception time information indicating the time at which the slave device 10 received a packet (e.g., a SYNC packet) transmitted by the master device 20. The transmitting unit 103 then transmits the packet to which the reception time information has been added by the reception time adding unit 108.

[0056] By employing this configuration, when a packet transmitted by the master device 20 is received by the slave device 10, the transmitter 103 transmits a packet having the reception time of the packet. This makes it possible to ascertain the reception time of the packet at the slave device 10 based on the packet. For example, as described above, when a packet having the reception time at the slave device 10 is transmitted to the packet capture device 30, the packet capture device 30 can obtain the reception time of the packet at the slave device based on the packet. Furthermore, when a packet having the reception time at the slave device 10 is transmitted to the control unit 100 of the slave device 10, the control unit 100 can obtain the reception time of the packet at the slave device 10 based on the packet.

[0057] FIG. 14 is a diagram showing another example of the main components of the slave device 10. The slave device 10 includes a transmitter 102, a transmission time acquisition unit 107, a transmission time addition unit 109, and a transmitter 103. Here, the transmitters 102 and 103 correspond to the communication interface 103 in FIG. 2, and the transmission time acquisition unit 107 corresponds to the transmission time information acquisition and retention unit 107. The transmitter 102 transmits a request packet (e.g., a DELAY_REQ packet) requesting a response to the master device. The transmission time acquisition unit 107 acquires transmission time information indicating the time when the transmitter 102 transmitted the request packet. When the transmitter 109 receives a response packet (e.g., a DELAY_RESP packet) in response to the request packet, the transmitter 103 adds the transmission time information acquired by the transmission time acquisition unit 107 to the response packet. The transmitter 103 transmits the response packet to which the transmission time information has been added by the transmission time addition unit 109.

[0058] By employing this configuration, when the slave device 10 transmits a request packet requesting a response to the master device, the transmission time of the packet is added to the packet and transmitted by the transmitter 102. This makes it possible to ascertain the transmission time of the packet in the slave device 10 based on the response packet. For example, as described above, when a packet having the transmission time of the request packet is transmitted to the packet capture device 30, the packet capture device 30 can obtain the transmission time of the request packet in the slave device 10 based on the packet. Furthermore, when a packet having the transmission time of the request packet is transmitted to the control unit 100 of the slave device 10, the control unit 100 can obtain the transmission time of the request packet in the slave device 10 based on the packet.

[0059] In the above-described embodiment, the reception time information of the SYNC packet transmitted by the master device 20 is added to the SYNC packet, but in other embodiments, the reception time information of the packet may be added to the Follow_Up packet transmitted by the master device 20. Note that the master device 20 adds the transmission time information of the SYNC packet at the master device 20 to the Follow_Up packet.

[0060] In this embodiment, when the slave device 10 receives a SYNC packet, the packet forwarding unit 104 notifies the reception time adding unit 108 of the sequence ID included in the SYNC packet. The reception time adding unit 108 holds this sequence ID. Next, when the slave device 10 receives a Follow_Up packet, the packet forwarding unit 104 forwards the Follow_Up packet to the reception time adding unit 108. Upon receiving the Follow_Up packet, the reception time adding unit 108 determines whether the sequence ID of the Follow_Up packet matches the sequence ID of the SYNC packet it holds. If these sequence IDs match, in other words, if the Follow_Up packet is included in a series of processes related to the SYNC packet, the reception time adding unit 108 adds reception time information indicating the reception time T2 of the Follow_Up packet to the padding area of ​​the Follow_Up packet. Here, when communication interface 101 receives the Follow_Up packet, reception time information acquisition and retention unit 106 acquires time information from counter 110, and reception time addition unit 108 adds this acquired time information to the Follow_Up packet as reception time information. Reception time addition unit 108 transmits the updated Follow_Up packet, to which reception time T2 of the Follow_Up packet has been added, to control unit 100 and packet capture device 30.

[0061] In the One-step mode defined in IEEE1588, SYNC packets can be used as the packets to which the reception time is assigned in the present invention. On the other hand, in the Two-step mode, it is more advantageous to use Follow_Up packets as the packets to which the reception time is assigned in the present invention. This is because the packets to which the transmission time T1 in the master device is assigned are limited to Follow_Up packets, which makes it possible to efficiently check the log, specifically the time information assigned to the Follow_Up packets.

[0062] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0063] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0064] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0065] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) A communication device that functions as a slave device that performs communication in accordance with the PTP (Precision Time Protocol) communication protocol, a reception time adding unit that adds reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; a transmitting unit that transmits a packet to which the reception time information has been added by the reception time adding unit; A communication device comprising: (Appendix 2) the transmitter is a first transmitter, a second transmitting unit that transmits a request packet requesting a response to the master device; a transmission time acquisition unit that acquires transmission time information indicating the time when the second transmission unit transmitted the request packet; a transmission time adding unit that adds the transmission time information acquired by the transmission time acquiring unit to a response packet when the response packet is received in response to the request packet transmitted by the second transmitting unit; a third transmitting unit that transmits a response packet to which the transmission time information has been added by the transmission time adding unit; 2. The communication device of claim 1, comprising: (Appendix 3) 3. The communication device according to claim 1, wherein the packet to which the reception time information is added is at least one of a SYNC packet and a Follow_Up packet transmitted by the master device. (Appendix 4) A communication device that functions as a slave device that performs communication in accordance with the PTP communication protocol, a transmitting unit that transmits a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; a transmission time acquisition unit that acquires transmission time information indicating the time when the transmission unit transmitted the request packet; a transmission time adding unit that adds the transmission time information acquired by the transmission time acquiring unit to the response packet when the response packet is received in response to the request packet transmitted by the transmitting unit; a transmitting unit that transmits a response packet to which the transmission time information has been added by the transmission time adding unit; A communication device comprising: (Appendix 5) the request packet is a DELAY_REQ packet, 5. The communication device according to claim 2, wherein the response packet is a DELAY_RESP packet. (Appendix 6) A communication method executed by a communication device functioning as a slave device that performs communication in accordance with the PTP communication protocol, adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; and transmitting the packet to which the reception time information is added. (Appendix 7) adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; transmitting a packet to which the reception time information is added; transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added. (Appendix 8) A communication method executed by a communication device functioning as a slave device that performs communication in accordance with the PTP communication protocol, transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added. (Appendix 9) For a communication device that functions as a slave device that communicates in accordance with the PTP communication protocol, adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; and transmitting the packet to which the reception time information is added. (Appendix 10) adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; transmitting a packet to which the reception time information is added; transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added. (Appendix 11) For a communication device that functions as a slave device that communicates in accordance with the PTP communication protocol, transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added.

[0066] Some or all of the elements in Appendix 3 that depend from Appendixes 1 and 2 may also depend, with similar dependencies, from Appendixes 6 and 7 and Appendixes 9 and 10. Some or all of the elements in Appendix 5 that depend from Appendix 4 may also depend, with similar dependencies, from Appendix 8 and Appendix 11. Some or all of the elements in any Appendix may be applicable to a variety of hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0067] 1: Communication Systems 10: Slave device 100: Control unit 101: Communication interface 102: Communication interface, transmitter 103: Communication interface, transmitter 104: Packet forwarding unit 105: Packet forwarding unit 106: Reception time information acquisition and storage unit 107: Transmission time information acquisition and storage unit, transmission time acquisition unit 108: Reception time addition section 109: Transmission time addition section 110: Counter 120: Packet processing unit 20: Master device 30: Packet capture device 40: Network 401: Relay device 402: Relay device

Claims

1. A communication device that functions as a slave device that performs communication in accordance with a PTP (Precision Time Protocol) communication protocol, a reception time adding unit that adds reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; a transmitting unit that transmits a packet to which the reception time information has been added by the reception time adding unit; A communication device comprising:

2. the transmitter is a first transmitter, a second transmitting unit that transmits a request packet requesting a response to the master device; a transmission time acquisition unit that acquires transmission time information indicating the time when the second transmission unit transmitted the request packet; a transmission time adding unit that, when receiving a response packet in response to the request packet transmitted by the second transmission unit, adds the transmission time information acquired by the transmission time acquiring unit to the response packet; a third transmitting unit that transmits a response packet to which the transmission time information has been added by the transmission time adding unit; The communication device of claim 1 , comprising:

3. 3. The communication device according to claim 1, wherein the packet to which the reception time information is added is at least one of a SYNC packet and a Follow_Up packet transmitted by the master device.

4. A communication device that functions as a slave device that performs communication in accordance with a PTP communication protocol, a transmitting unit that transmits a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; a transmission time acquisition unit that acquires transmission time information indicating the time when the transmission unit transmitted the request packet; a transmission time adding unit that adds the transmission time information acquired by the transmission time acquiring unit to the response packet when the response packet is received in response to the request packet transmitted by the transmitting unit; a transmitting unit that transmits a response packet to which the transmission time information has been added by the transmission time adding unit; A communication device comprising:

5. A communication method executed by a communication device functioning as a slave device that performs communication in accordance with a PTP communication protocol, comprising: adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; and transmitting the packet to which the reception time information is added.

6. adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; transmitting a packet to which the reception time information is added; transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; 6. The communication method according to claim 5, further comprising the step of transmitting a response packet to which the transmission time information is added.

7. A communication method executed by a communication device functioning as a slave device that performs communication in accordance with a PTP communication protocol, comprising: transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added.

8. A communication device that functions as a slave device and performs communication in accordance with the PTP communication protocol, adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; and transmitting the packet to which the reception time information is added.

9. adding reception time information indicating the time at which the slave device received a packet transmitted by a master device that performs communication in accordance with the PTP communication protocol; transmitting a packet to which the reception time information is added; transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added.

10. A communication device that functions as a slave device and performs communication in accordance with the PTP communication protocol, transmitting a request packet requesting a response to a master device that performs communication in accordance with the PTP communication protocol; acquiring transmission time information indicating the time when the request packet was transmitted; adding the acquired transmission time information to a response packet when the response packet is received in response to the request packet; and transmitting a response packet to which the transmission time information is added.

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