Relay device, communication network system, relay method, and computer program

Abstract

To provide a relay device capable of appropriately setting priority order for communication based on clock accuracy required according to the function of each master.SOLUTION: A relay device 5 relays communication performed between a GM 1, a GM 2 and slaves 3 and 4 via a communication network 6. At that time, a time synchronization support unit 11 sets a lower priority for communication for a time synchronization communication frame transmitted from the GM 1 or GM 2, for a function of the GM 1 or GM 2 that requires relatively low clock accuracy.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an apparatus for relaying communication performed between a plurality of masters and a plurality of slaves via a communication network, a communication network system including the apparatus, a relaying method, and a computer program.

Background Art

[0002] In Time Sensitive Network (TSN), which is a type of Ethernet (registered trademark) used for in-vehicle communication, time synchronization provided is designed with a target accuracy of less than 1 microsecond.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, devices connected to an in-vehicle communication network include those related to autonomous driving and those related to infotainment systems. In these devices, the time synchronization accuracy required for communication varies depending on their functions. However, in the prior art, no particular consideration has been given to how to control communication in accordance with the time synchronization accuracy of each device.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a relay device capable of appropriately setting a priority order for communication based on the clock accuracy required according to the function of each master, a communication network system including the device, a relaying method, and a computer program.

Means for Solving the Problems

[0006] The relay device according to claim 1 relays communication performed between a plurality of masters (1, 2) and a plurality of slaves (3, 4) via a communication network (6). At this time, the time synchronization corresponding unit (11) sets a lower priority for communication in the time synchronization communication frame transmitted from the master for those with relatively low clock accuracy required for the functions of each master. Note that the "clock" in this application means time. As a result, even if there are a plurality of masters with different clock accuracies required for their respective functions, the time synchronization corresponding unit appropriately sets the priority to avoid conflicts, and communication of the master with relatively high clock accuracy is preferentially performed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0008] (First Embodiment) As shown in FIG. 1, in the in-vehicle communication system of this embodiment, for example, two masters GM1 and 2 and, for example, two slaves 3 and 4 are connected via a communication network 6 including a relay device 5 and communicate with each other. Ethernet (registered trademark) is adopted for the communication network. GM1 and 2 and slaves 3 and 4 are all electronic control units; ECUs (Electronic Control Units) mounted on the vehicle. The communication network 6 includes a relay device 5, switches 7 and 8 arranged between the relay device 5 and the slave 3, switches 9 and 10 arranged between the relay device 5 and the slave 4, and the like.

[0009] Switches 7, 8, 9, and 10 are respectively arranged in, for example, four regions of the front, rear, left, and right of the vehicle, and transfer communications between ECUs arranged in each region. Switches 7, 8, 9, and 10 may be zone ECUs. Also, as shown in FIG. 1, the relay device 5 and switches 7, 8, 9, and 10 are connected in a ring shape to form a ring topology. Note that it is not limited to the ring topology, and other network topologies such as a mesh type may be used.

[0010] GM1 and 2 comply with the communication protocol IEEE802.1AS-2020. Also, GM1 and 2 do not comply with IEEE802.1q, that is, they do not support the VLAN (Virtual Local Area Network) function. VLAN is a technology for dividing one physical switch into multiple virtual switches for use. Slaves 3 and 4 comply with the communication protocol AUTOSAR (AUTomotive Open System ARchitecture), that is, IEEE802.1AS-2011. AUTOSAR is the specification name of a platform for realizing the commonization of in-vehicle software.

[0011] Slaves 3 and 4 comply with IEEE802.1q, that is, they support the VLAN function. Also, slaves 3 and 4 support the QoS (Quality of Service) method that classifies and groups application data and conducts communication according to the priority of each group, that is, they comply with IEEE802.1p.

[0012] Relay device 5 complies with the communication protocol IEEE802.1AS-2020. Relay device 5 also complies with the communication protocol AUTOSAR, that is, IEEE802.1AS-2011. Also, relay device 5 complies with IEEE802.1q and IEEE802.1p, that is, it supports the VLAN function and the QoS method.

[0013] Switches 7, 8, 9, and 10 comply with the communication protocol IEEE802.1AS-2020. Switches 7, 8, 9, and 10 also comply with the communication protocol AUTOSAR, that is, IEEE802.1AS-2011. Also, switches 7, 8, 9, and 10 comply with IEEE802.1q and IEEE802.1p, that is, they support the VLAN function and the QoS method. Note that GM1 and 2 do not comply with IEEE802.1p.

[0014] Data transmitted from GM1 and 2 is transferred to slaves 3 and 4 via the communication line, relay device 5, and switches 7, 8, 9, and 10. Specifically, in FIG. 1, data transmitted from GM1 and 2 is transferred to slave 3 via relay device 5 and switches 7 and 8. Also, data transmitted from GM1 and 2 is transferred to slave 4 via relay device 5 and switches 9 and 10. Note that data transmitted from GM1 and 2 may be transferred to slaves 3 and 4 via, for example, the communication line, relay device 5, and switches 7, 8, and 10. That is, it may be transferred without passing through switch 9.

[0015] The relay devices 5 each include a control unit (not shown) and a memory, and the control unit is provided with a time synchronization corresponding unit 11. The time synchronization corresponding unit 11 adds information regarding the priority corresponding to QoS to the time synchronization communication frame included in the above data, and transfers it to the slaves 3 and 4 via the switches 7, 8, 9, and 10. Hereinafter, the time synchronization communication frame may sometimes be simply referred to as a communication frame.

[0016] Figure 2 shows a system configuration closer to an actual use case. GM1 is, for example, the main clock source 1, and the clock quality as the required time accuracy, that is, the clock accuracy, is "medium". GM2 is, for example, the backup clock source 2, and the clock quality is "low". The switches 7 and 8, and the switches 9 and 10 are collectively shown as one bridge 12, 13, respectively. Although not shown in Figure 2, there may be a communication line connecting the bridge 12 and the bridge 13.

[0017] The slave 3 includes an end station 14 which is a communication node, and a clock target 15 that operates by the clock supplied by GM1 or 2. Similarly, the slave 4 includes an end station 16 and a clock target 17. One or more end stations 14 and 16 are included in each of the slaves 3 and 4. One clock target 15 is provided so as to correspond to each of the end stations 14 and 16. The above constitutes an in-vehicle communication system 18 which is a communication network system.

[0018] This system configuration is a multiplexed network that operates the main and backup clock sources simultaneously. When GM1 with higher clock quality than GM2 is operating normally, there is no need to increase the transmission priority of GM2 which is a backup. In other words, when GM1 with higher clock quality than GM2 is operating normally, there is no need to increase the transmission priority of GM2 with lower clock quality than GM1. That is to say, it is desirable that the data transmission of GM2 as a backup does not interfere with the data transmission of GM1 as the main.

[0019] Therefore, the relay device 5 dynamically sets, from the announcement message included in the communication data, a combination of parameters of the main and backup clock qualities, for example, the clock quality and the MAC (Media Access Control) address of the device that performs transmission, and determines the QoS value, which is the transmission priority, based on the parameters. When the main clock is lost, as will be described later, the transmission priority that has been lowered once is set to be restored.

[0020] Next, the operation of this embodiment will be described. As shown in FIG. 3, if the time synchronization corresponding unit 11 of the relay device 5 has, as static parameter information, association information of the QoS value setting and the MAC, which is a combination of the QoS value setting and the MAC address, the time synchronization corresponding unit 11 determines the QoS value setting and the association information of the MAC based on them. The static parameter information is information in which the QoS value setting and the association information of the MAC are defined in advance as a system. If there is no static parameter information, an initial value is set (S1). Then, the determined QoS value and the association information of the MAC, or the initial value, are stored in a storage medium such as a memory (S2). Note that the determination of the QoS value setting and the association information of the MAC in step S1 may be performed as necessary, or only the setting of the initial value may be performed instead. That is, regardless of the presence or absence of the static parameter information, only the initial value may be set.

[0021] Next, it is determined whether the communication frame received from GM1 or 2 is an announce message (S3). Regarding the announce message shown in FIG. 5, it is shown as Table 10-11 - Announce message fields in 10.6.3.1 General Announce message specifications of the standard IEEE Std 802.1AS (Registered Trademark)-2020. If the received communication frame is an announce message (Yes), it is determined whether it is the GM with the highest transmission priority (S6). For example, it may be determined whether it is the GM with the highest transmission priority through arbitration called BMCA (Best Master Clock Algorithm).

[0022] If it is the GM with the highest transmission priority (S6; Yes), it is determined whether there are still frames to be received (S5). If there are still frames to be received (Yes), the process returns to step S3. If there are no received frames (No), the process ends. On the other hand, if it is not the GM with the highest transmission priority (S6; No), the QoS value setting and the MAC association information are determined based on the announce message (S7), and the QoS value setting and the MAC association information are stored in a memory or the like in the same manner as in step S2 (S8). Then, a QoS value based on the QoS value setting and the MAC association information is added to the frame (S9), and the process proceeds to step S5.

[0023] As shown in FIG. 6, the addition of the above QoS value is performed by setting eight levels of priority from the lowest "0" to the highest "7" in the 3-bit CoS (Class of Service) area in the 4-byte VLAN tag area in the Ethernet frame format. For example, if "1" is the default setting among the priorities "0" to "7", the priority "1" may be set to correspond to the 3 bits of "000". The priority "0" may be set to correspond to "001", "2" to "010", "3" to "011", "4" to "100", "5" to "101", "6" to "110", and "7" to "111" of the 3 bits.

[0024] In step S3, if the received communication frame is not an announcement message (No), it is determined from the QoS value saved in step S2 and the MAC association information whether it is a frame from a GM for which the transmission priority may be lowered (S4). If it is a frame from a GM for which the transmission priority may be lowered (Yes), the process proceeds to step S9.

[0025] As shown in FIG. 4, in the process in step S7, first, it is determined whether the setting of grandmasterPriority1 in the announcement message of the received communication frame is 0 or 1 (S11). If this setting is 0 or 1 (Yes), in the announcement message, it is determined whether the clockAccuracy indicated by the setting of grandmasterClockQuality is, for example, "29" or more (S12). In step S11, if the setting is not 0 or 1 (No), it is determined that it is a GM for which the transmission priority may be lowered, and the CoS value to be set in the CoS area is subtracted, for example, by "1" from the value set at that time (S14). In other words, the transmission priority set in the CoS area is lowered to the next lower transmission priority. Then, the process proceeds to step S12.

[0026] In step S12, if the clockAccuracy indicated by the setting of grandmasterClockQuality in the announcement message is not "29" or more (No), it is determined that it is a GM for which the transmission priority may be lowered in the same manner as in step S14, and the CoS value is subtracted, for example, by "2" from the value set at that time (S15). In other words, the transmission priority set in the CoS area is lowered to the next lower transmission priority. Then, the process proceeds to step S13, and the QoS value is set from the subtraction result of the CoS value. When uniformly adding or subtracting the CoS value, the addition or subtraction is performed here. Which of "0 to 6" other than the highest transmission priority of "7" is set depends on the system. Note that when it is determined as (Yes) in step S12, since the CoS value has not been subtracted, the CoS value and the QoS value remain the initial values.

[0027] As described above, according to this embodiment, the relay device 5 relays the communication performed between the GMs 1 and 2 and the slaves 3 and 4 via the communication network 6. At this time, the time synchronization support unit 11 sets a lower priority for communication with respect to the time synchronization communication frame transmitted from the GM 1 or 2 for which the clock accuracy required for the function of the GM 1 or 2 is relatively low. As a result, even if the clock accuracies required for the functions of the GMs 1 and 2 are different, the time synchronization support unit 11 appropriately sets the priorities to avoid conflicts, and the communication of the GM with a relatively high clock accuracy is preferentially performed.

[0028] More specifically, when the protocol of the communication network 6 conforms to IEEE802.1p, the time synchronization support unit 11 determines the transmission priority based on the grandmasterPriority1y and grandmasterClockQuality included in the announcement message in the time synchronization communication frame. In the communication protocol IEEE802.1p, the grandmasterPriority1 in the announcement message is an area that directly designates the priority of the GM, the grandmasterClockQuality is an area that sets the relative clock quality of the GM, and the clockAccuracy in the grandmasteClockQuality is related to the relative clock accuracy. Therefore, the time synchronization support unit 11 can appropriately set the communication priority based on the information stored in these areas.

[0029] In addition, the time synchronization support unit 11 sets the priority in the CoS area in the time synchronization communication frame. In the Ethernet frame format, a 3-bit CoS area is set to set the communication priority, so the priority can be set using the pre-reserved area.

[0030] (Second Embodiment) Hereinafter, the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted, and the different parts will be described. As shown in FIG. 7, in the second embodiment, unlike the method of dynamically setting the priority order for the relay device 5 to perform communication based on the information included in the announcement message as in the first embodiment, a case of static setting is shown. Here, "statically setting" means setting based only on static parameter information. The static parameter information is stored in advance in a memory of the relay device 5, for example, which is a predetermined area.

[0031] In step S11, which replaces step S1, QoS value setting and determination of MAC association information are performed based on static parameter information. Here, unlike in step S1, there is no such arbitrariness as "if necessary", and setting and the like are always performed based on static parameter information. Subsequently, steps S2, S4, and S5 are executed. That is, from the flowchart of FIG. 4 in the first embodiment, steps S3, S6 to S8 are deleted.

[0032] As described above, according to the second embodiment, the relay device 5 performs QoS value setting and determination of MAC association information based on the static parameter information prepared in advance as system information of the communication network 6.

[0033] (Other embodiments) The order of steps S11 and S12 may be reversed. The value to be subtracted from the CoS value in steps S14 and S15 may be changed as appropriate. In both steps S14 and S15, the same value, for example, "1", may be subtracted from the CoS value. In steps S14 and S15, it is sufficient that the priority can be lowered, and any method other than subtracting the CoS value may be used. The current priority may be judged from the CoS value, and the process may be performed so as to obtain the CoS value of the lowered priority, or the process of directly instructing the priority may be used. The master does not necessarily have to comply with the communication protocol IEEE802.1AS-2020, and the slave does not necessarily have to comply with the communication protocol of AUTOSAR either. Also, the switch does not necessarily have to comply with the communication protocol IEEE802.1AS-2020.

[0034] The number of masters and slaves may be 3 or more. Switches 7, 8, 9, and 10 are not necessarily required, and it may be in a form where the relay device 5 is connected to a plurality of slaves 3 and 4. The master and the slave do not necessarily have to be electronic control devices. It may be applied to a network system other than the in-vehicle communication system. The priority does not necessarily have to be determined based on the grandmasterPriority and grandmasterClockQuality included in the announcement message. For example, it may be determined based on other information or parameters indicating the priority of the GM and the relative accuracy of the GM's clock. Also, the priority does not necessarily have to be set in the CoS area within the time synchronization communication frame.

[0035] Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and forms, and further other combinations and forms including only one element, more than one, or less than one of them, are within the scope and thinking scope of the present disclosure.

[0036] The means and / or functions provided by each device or the like can be provided by software recorded in a physical memory device and a computer that executes it, software only, hardware only, or a combination thereof. For example, when the control device is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a number of logic circuits or an analog circuit.

[0037] The control unit and its method described in the present disclosure may be implemented by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and its method described in the present disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Or, the control unit and its method described in the present disclosure may be implemented by one or more dedicated computers configured by a combination of a processor programmed to execute one or more functions and a memory and a processor configured by one or more hardware logic circuits. Further, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

Explanation of Signs

[0038] In the drawings, 1 and 2 represent GM, 3 and 4 represent slaves, 5 represents a relay device, 6 represents a communication network, 11 represents a time synchronization corresponding unit, and 18 represents an in-vehicle communication system.

Claims

1. A relay device that relays communication between a plurality of masters (1, 2) and a plurality of slaves (3, 4) via a communication network (6), and includes a time synchronization corresponding unit (11) that sets a lower priority for communication for those with relatively low clock accuracy required for the functions of each master in the time synchronization communication frame transmitted from the master.

2. The relay device according to claim 1, wherein the time synchronization corresponding unit determines the priority based on information or parameters indicating the priority order of the masters included in the time synchronization communication frame and information or parameters indicating the relative accuracy of the clocks of the masters.

3. The protocol of the communication network conforms to IEEE 802.1p, and the relay device according to claim 1, wherein the time synchronization corresponding unit determines the priority based on grandmasterPriority and grandmasterClockQuality included in the announcement message in the time synchronization communication frame.

4. The relay device according to claim 3, wherein the time synchronization corresponding unit sets the priority in the CoS (Class of Service) area in the time synchronization communication frame.

5. Information regarding the clock accuracy of each master is stored in a predetermined area in advance, and the relay device according to claim 1, wherein the time synchronization corresponding unit determines the priority based on the information stored in the predetermined area.

6. A communication network system comprising the relay device according to any one of claims 1 to 5, the plurality of masters, and the plurality of slaves.

7. A method for relaying communication between a plurality of masters and a plurality of slaves via a communication network, the method comprising: for a time synchronization communication frame transmitted from the master, setting a lower priority for communication for those with relatively low clock accuracy required for the functions of each master.

8. The relay method according to claim 7, wherein the priority is determined based on information or parameters indicating the priority order of the masters included in the time synchronization communication frame and information or parameters indicating the relative accuracy of the clocks of the masters.

9. The protocol of the communication network conforms to IEEE 802.1p, The relay method according to claim 7, wherein the priority is determined based on grandmasterPriority and grandmasterClockQuality included in an announcement message within the time synchronization communication frame.

10. The relay method according to claim 9, wherein the priority is set in a CoS (Class of Service) area within the time synchronization communication frame.

11. Information regarding the clock accuracy of each master is stored in a predetermined area in advance, The relay method according to claim 9, wherein the priority is determined based on information stored in the predetermined area.

12. A program executed by a computer that configures a device for relaying communication performed between a plurality of masters and a plurality of slaves via a communication network, A computer program that causes a time synchronization communication frame transmitted from the master to set a lower priority for communication for those masters that require relatively low clock accuracy for their functions.

13. The computer program according to claim 12, wherein the priority is determined based on information or parameters indicating the priority order of the masters included in the time synchronization communication frame and information or parameters indicating the relative accuracy of the clocks of the masters.

14. When the protocol of the communication network complies with IEEE802.1p, The computer program according to claim 12, wherein the priority is determined based on grandmasterPriority and grandmasterClockQuality included in an announcement message within the time synchronization communication frame.

15. The computer program according to claim 14, wherein the priority is set in a CoS (Class of Service) area within the time synchronization communication frame.

16. When information regarding the clock accuracy of each master is stored in a predetermined area in advance, The computer program according to claim 12, wherein the priority is determined based on information stored in the predetermined area.

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