JP7704020B2 - Repeater - Google Patents

Description

The present invention relates to a relay device that relays communication between multiple connection nodes that perform request-reply type information acquisition communication.

Conventionally, an electronic control device mounted on a vehicle such as an automobile communicates with other electronic control devices also mounted on the vehicle, and also communicates with a data center or the like provided outside the vehicle. In this specification, the electronic control device may be referred to as an ECU, which is an abbreviation for the electronic control device. Of the above-mentioned communications, the communication between the ECU and a data center or the like is performed when using a cloud application in the vehicle, and therefore can be rephrased as communication between the ECU and a cloud application.

As disclosed in Patent Document 1, in such a communication system, an ECU may be provided that functions as a relay device that relays communication between multiple ECUs and communication between the ECU and a cloud application. In a communication system in which such a relay device is provided, the ECU and the cloud application are nodes that are connected to the relay device. Thus, in this specification, the ECU and the cloud application may be collectively referred to as a connection node.

JP 2021-048439 A

In conventional relay devices, when the number of connection nodes increases and communication volume increases, the communication bus load between the relay device and the connection nodes increases, which can cause problems such as a decrease in communication quality. In addition, in conventional relay devices, when communication volume increases, many of the computing resources in the connection nodes are used for communication, which can cause problems such as fewer computing resources being allocated to essential control processing.

In vehicle-mounted communication systems, request-reply type information acquisition communication may be adopted for communication between connection nodes. When this type of communication is adopted, the following problem occurs with conventional relay devices. That is, there may be cases where multiple connection nodes issue the same request to another connection node. In such cases, the relay device will forward the same communication data to the same destination multiple times, which may result in wasteful communication and increased load on the communication bus.

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a relay device that can reduce the communication load between connection nodes and the processing load at the connection node to which the request is sent.

The relay device described in claim 1 relays communication between a plurality of connection nodes (3-8) that perform request-reply type information acquisition communication. Here, when a connection node that transmits a request for requesting information acquisition is defined as a request source node, and a connection node that receives the request and returns a reply including the information requested by the request source node to the request source node is defined as a request destination node, the relay device comprises a memory unit (11), a memory processing unit (14, 23), a judgment processing unit (15), and a relay processing unit (16, 24).

The storage unit can store the reply. When the storage processing unit relays a reply returned from the request destination node to the request source node, it executes a storage process to store the reply in the storage unit. The determination processing unit executes a determination process to determine whether or not a corresponding reply, which is a reply corresponding to a relay target request, which is a request to be relayed, exists among the replies stored in the storage unit when relaying a request transmitted from the request source node to the request destination node. If a corresponding reply exists, the relay processing unit executes a return process to return the corresponding reply stored in the storage unit as a reply to the relay target request to the request source node without transmitting the relay target request to the request destination node. When executing the storage process, the storage processing unit (23) is configured to store the reply by adding a reply time, which is a time corresponding to the time when the reply was relayed, to the reply. The relay processing unit (24) judges whether the corresponding reply is valid based on whether the elapsed time from the reply time of the corresponding reply to the current time is within a predetermined elapsed time, and executes a return process if the elapsed time of the corresponding reply is within the elapsed time and the corresponding reply is judged to be valid, and executes a relay process to transmit the request to be relayed to the request destination node if the elapsed time of the corresponding reply exceeds the elapsed time and the corresponding reply is judged to be invalid. The elapsed time includes AT-D, which is a time individually set for each request destination node, AT-S, which is a time individually set for each piece of information requested by a request, and AT-C, which is a time individually set for each request transmitted by the request source node. When transmitting a request, the request source node assigns AT-C to the request. Priorities are set for AT-D, AT-S, and AT-C to be used in judging whether the corresponding reply is valid.

With this configuration, in cases where multiple connection nodes issue the same request to one other connection node, the relay device will not forward the same communication data to the same destination multiple times, specifically, the relay device will not forward the same request to the same request destination node multiple times, resulting in a reduction in communication between the relay device and the request destination node, and a reduction in the processing load on the request destination node. Therefore, with the above configuration, the excellent effect of reducing the communication load between connection nodes and the processing load on the request destination connection node can be obtained.

FIG. 1 is a diagram illustrating a configuration of a communication system including a relay device according to a first embodiment; FIG. 2 is a diagram illustrating an example of a data structure of a request according to the first embodiment; FIG. 1 is a diagram illustrating an example of a data structure of a reply according to the first embodiment; FIG. 2 is a diagram illustrating an example of a data structure of stored data according to the first embodiment; FIG. 1 is a diagram for explaining input and output of a relay device according to a first embodiment; FIG. 4 is a diagram illustrating a process flow related to relaying communication executed by a relay device according to the first embodiment; FIG. 1 is a diagram for explaining a specific example in which a relay device according to the first embodiment relays communication and returns a reply; FIG. 1 is a diagram for explaining a specific example in which a relay device according to the first embodiment returns a reply without relaying communication. FIG. 11 is a diagram illustrating a configuration of a communication system including a relay device according to a second embodiment. FIG. 11 is a diagram for explaining input to a relay device during configuration according to the second embodiment; FIG. 11 is a diagram for explaining input/output of a relay device during relay processing and parameter setting according to the second embodiment; FIG. 13 is a diagram showing a data structure of setting parameters of the AT-D according to the second embodiment; FIG. 13 is a diagram showing a data structure of setting parameters of the AT-S according to the second embodiment; FIG. 13 is a diagram illustrating an example of a data structure of a request according to a second embodiment. FIG. 13 is a diagram illustrating an example of a data structure of stored data according to a second embodiment; FIG. 13 is a diagram illustrating an example of data in a management table according to the second embodiment; FIG. 11 is a diagram illustrating the content of a parameter setting process according to a second embodiment. FIG. 11 is a diagram illustrating a process flow related to relaying communication executed by a relay device according to a second embodiment. FIG. 11 is a diagram illustrating the contents of an AT setting process according to the second embodiment. FIG. 11 is a diagram for explaining a specific example in which a relay device according to the second embodiment relays communication and returns a reply; FIG. 11 is a diagram for explaining a specific example in which a relay device according to the second embodiment does not relay communication but returns a reply using an AT-C. FIG. 11 is a diagram for explaining a specific example in which a relay device according to the second embodiment does not relay communication but returns a reply using AT-S. FIG. 11 is a diagram for explaining a specific example in which a relay device according to the second embodiment does not relay communication but returns a reply using AT-D.

Hereinafter, a number of embodiments of the present invention will be described with reference to the drawings. Note that in the respective embodiments, substantially the same configurations are given the same reference numerals and the description thereof will be omitted.
First Embodiment
Hereinafter, the first embodiment will be described with reference to FIGS.

As shown in FIG. 1, the relay device 1 of this embodiment is used in a communication system of a vehicle 2, such as an automobile, and relays communications between multiple ECUs 3-7 mounted on the vehicle 2, and between the multiple ECUs 3-7 and a cloud application 8 external to the vehicle 2. The relay device 1 is composed of an ECU mounted on the vehicle 2. The relay device 1 and the ECUs 3-7 can communicate with each other via an on-board communication bus 9. The relay device 1 and the cloud application 8 can communicate with each other via a network 10. Examples of the network 10 include a mobile communication network and a wireless LAN.

ECUs 3 to 7 are so-called domain ECUs. ECU 3 is an ADASECU that provides integrated control of the entire advanced driving assistance system. ECU 4 is a meter ECU that provides integrated control of the entire meter display. ECU 5 is a navigation ECU that provides integrated control of the entire navigation function. ECU 6 is a body ECU that provides integrated control of all body equipment. ECU 7 is an engine ECU that provides integrated control of the engine drive system.

In the following explanation and in the drawings such as FIG. 1, ECUs 3, 4, 5, 6, and 7 may be referred to as ADASECU 3, meter ECU 4, navigation ECU 5, body ECU 6, and engine ECU 7, respectively. Also, FIG. 1 illustrates only ECUs 3 to 7, which are some of the domain ECUs mounted on vehicle 2, but in reality there are other domain ECUs besides these. Communications for other domain ECUs not shown are also relayed by relay device 1 in the same manner as ECUs 3 to 7.

Cloud application 8 corresponds to various cloud services implemented by a data center or the like provided outside vehicle 2. ECUs 3 to 7 and cloud application 8 are all nodes connected to relay device 1, and correspond to multiple connection nodes. ECUs 3 to 7 and cloud application 8, which correspond to multiple connection nodes, are configured to perform request-reply type information acquisition communication.

In the following description, a connection node that transmits a request to obtain information may be referred to as a requesting node, and a connection node that receives a request and returns a reply including the information requested by the requesting node to the requesting node may be referred to as a requested destination node. The relay device 1 performs the following relay operation as its basic operation. That is, when the relay device 1 receives a request transmitted from the requesting node, it relays the request to the requested destination node, and when it receives a reply returned from the requested destination node, it relays the reply to the requesting node.

The relay device 1 includes a memory unit 11, a communication unit 12, and a control unit 13. The memory unit 11 is composed of various storage devices, such as ROM and RAM, and is capable of storing replies. Note that the memory unit 11 may also be a separately provided storage device for storing various data other than replies. The memory unit 11 is a large-capacity storage device having a storage capacity large enough to store at least replies. The communication unit 12 is a communication interface that communicates with the ECUs 3 to 7 and the cloud application 8 via a network port provided in the relay device 1.

The control unit 13 is configured to include, for example, a CPU capable of software calculations. The control unit 13 has functional blocks such as a storage processing unit 14, a judgment processing unit 15, and a relay processing unit 16. Each of these functional blocks is realized by the CPU of the control unit 13 executing a computer program stored in a non-transitive physical storage medium to execute processing corresponding to the computer program, that is, by software. Note that at least a portion of each functional block may be configured to be realized by hardware.

When the storage processing unit 14 relays a reply sent from the request destination node to the request source node, it executes a storage process to store the reply in the storage unit 11. In addition, when executing the storage process, if a reply corresponding to the same request as the relayed reply has already been stored in the storage unit 11, the storage processing unit 14 is configured to delete the stored reply.

The determination processing unit 15 executes a determination process to determine whether or not a corresponding reply corresponding to the request to be relayed exists among the replies stored in the memory unit 11 when relaying a request sent from the request originating node to the request destination node. The request to be relayed is the request to be relayed, and the corresponding reply is a reply corresponding to the relay request. The relay processing unit 16 executes a return process to return the corresponding reply stored in the memory unit 11 to the request originating node as a reply to the request to be relayed, without sending the request to be relayed to the request destination node, if a corresponding reply exists.

In the above configuration, the request exchanged between the connection nodes and accepted by the relay device 1 has a data structure, for example, as shown in FIG. 2. That is, the request includes a request key. The request key is a character string that represents the information requested by the requesting node, and is uniquely determined for the information to be acquired. Specifically, the request key is, for example, GPS location information, cloud application status, trunk door lock status, headlight status, etc.

In this case, the request destination node to which the request key is sent is uniquely determined depending on the contents of the request key. For example, if the request key is cloud app status, the request destination node to which the request including the request key is sent is cloud application 8. Also, for example, if the request key is trunk door lock status, the request destination node to which the request including the request key is sent is body ECU 6.

In the above configuration, the reply exchanged between connection nodes and returned by relay device 1 has a data structure, for example, as shown in FIG. 3. That is, the reply includes a request key and reply data. The request key is a character string corresponding to the request key of the request, and is uniquely determined for the information provided by the request destination node. The reply data is information provided by the request destination, and various data formats can be adopted, for example, character strings, numbers, binary, etc. For example, when the request key is "trunk door lock status", the reply data will be data such as "Locked" or "Unlocked".

In the above configuration, the reply relayed by the relay device 1 is stored in the memory unit 11 as stored data, which has a data structure such as that shown in FIG. 4. That is, the stored data includes a request key and reply data, just like the reply.

As shown in FIG. 5, the relay device 21 communicates with the connection nodes, which are the ECUs 3 to 7 and the cloud application 8, and inputs and outputs data as follows. That is, when relaying, the relay device 21 receives a request from the connection node Na, which is the request source node, and outputs the request to the connection node Nb, which is the request destination node. Also, when relaying, the relay device 21 receives a reply from the connection node Nb, and outputs a reply to the connection node Na.

At this time, the relay device 21 stores the reply input from the connection node Nb in the memory unit 11. The reply is stored by overwriting the old stored data that contains the same request key. However, if the relay device 21 does not relay the request and retrieves the stored data that is the corresponding reply from the memory unit 11, no input/output is performed to the connection node Nb.

Next, the flow of processing related to relaying communication executed by the relay device 1 configured as above will be described with reference to FIG. 6. Note that the relay device 1 is configured to repeatedly execute the processing shown in FIG. 6, that is, the request-reply relay processing, at a predetermined cycle. First, in step S101, the relay device 1 receives a request sent from the request source node. After executing step S101, the process proceeds to step S102.

In step S102, it is determined whether or not a reply containing a request key that matches the request key contained in the received request to be relayed, that is, a corresponding reply, is present in the saved data stored in memory unit 11. In other words, step S102 is a processing step corresponding to the determination process described above. Here, if a corresponding reply is not present in memory unit 11, step S102 becomes "NO" and the process proceeds to step S103. In step S103, the request to be relayed is sent to the request destination node. In other words, step S103 is a processing step corresponding to the relay process of relaying a request.

After step S103 is executed, steps S104 to S106 are executed in this order. In step S104, the relay device 1 receives a reply sent back from the requested node. In step S105, the reply received in step S104 is stored in the memory unit 11 as saved data. In other words, step S105 is a processing step corresponding to the storage processing described above. In step S106, the reply received in step S104 is sent back to the request source node. After step S106 is executed, this processing ends.

On the other hand, if a corresponding reply exists in memory unit 11, step S102 becomes "YES" and the process proceeds to step S107. In step S107, stored data corresponding to the corresponding reply is retrieved from memory unit 11. After step S107 is executed, the process proceeds to step S108. In step S108, the stored data corresponding to the corresponding reply retrieved in step S107 is returned to the request source node as a reply corresponding to the request to be relayed. After step S108 is executed, this process ends.

Next, the operation of the relay device 1 when communication is performed between the connection nodes of the above configuration will be described with reference to the specific example shown in Figures 7 and 8. Note that the specific example shown in Figures 7 and 8 represents communication when the meter ECU 4 obtains the trunk door lock status from the body ECU 6. Also, in Figures 7 and 8, etc., illustrations of components that are not necessary for the explanation of the operation are omitted.

[1] When the relay device relays communication and returns a reply As shown in Fig. 7, when the relay device 1 receives a request including a request key indicating the "trunk door lock status" transmitted from the meter ECU 4, it judges whether or not it is possible to return the data stored in the memory unit 11 as a reply, that is, it executes the judgment process described above. In this case, it is assumed that there is no corresponding reply in the memory unit 11. Therefore, the relay device 1 transfers the request as it is to the body ECU 6, which is the request destination node.

After that, when the relay device 1 receives a reply corresponding to the request key from the body ECU 6, which is the request destination node, the relay device 1 relays the reply to the meter ECU 4, which is the request source node. At this time, the relay device 1 stores the relayed reply as saved data in the memory unit 11, that is, executes the storage process described above.

[2] When the relay device returns a reply without relaying communication As shown in Fig. 8, when the relay device 1 receives a request including a request key indicating the "trunk door lock status" transmitted from the meter ECU 4, the relay device 1 judges whether or not the stored data in the memory unit 11 can be returned as a reply, that is, executes the judgment process described above. In this case, it is assumed that a corresponding reply exists in the memory unit 11. Therefore, the relay device 1 retrieves the stored data stored in the memory unit 11 and transfers the stored data to the meter ECU 4, which is the request source node, as a reply, that is, executes the return process described above. In this case, the body ECU 6, which is the request destination node, does not execute any operation related to communication.

According to the present embodiment described above, the following effects can be obtained.
According to the above configuration, in a case where multiple connection nodes issue the same request to one other connection node, the relay device 1 does not forward the same communication data to the same destination multiple times, specifically, the relay device 1 does not forward the same request to the same request destination node multiple times, and as a result, the communication traffic between the relay device 1 and the request destination node is reduced, and the processing load at the request destination node is also reduced. Therefore, according to this embodiment, it is possible to obtain the excellent effect of reducing the communication load between the connection nodes and the processing load at the request destination connection node.

In the above configuration, when the storage processing unit 14 executes the storage process, if a reply corresponding to the same request as the relayed reply is stored in the storage unit 11, the storage processing unit 14 deletes the stored reply. In this way, if the relay device 1 relays replies corresponding to the same request multiple times, only the most recent data of the multiple replies will remain in the storage unit 11, and older data will be deleted. Therefore, with the above configuration, the storage capacity of the storage unit 11 can be effectively utilized, and as a result, it is no longer necessary to use a storage unit 11 with an unnecessarily large storage capacity, and the manufacturing costs of the relay device 1 can be reduced accordingly.

Second Embodiment
The second embodiment will be described below with reference to FIGS.
9, relay device 21 of the present embodiment differs from relay device 1 of the first embodiment shown in FIG 1 in that it includes a control unit 22 instead of control unit 13. Control unit 22 differs from control unit 13 in that it includes a storage processing unit 23 instead of storage processing unit 14, and a relay processing unit 24 instead of relay processing unit 16.

When the storage processing unit 23 executes the storage process, it assigns to the reply the reply time, which is the time when the reply was relayed, that is, the time corresponding to the time when the relay device 1 received the reply, and stores the reply. The relay processing unit 24 executes a return process if the elapsed time from the reply time of the corresponding reply to the current time is within a predetermined elapsed time, and executes a relay process to send a relay response request to the request destination node if the elapsed time of the corresponding reply exceeds the elapsed time. Note that in this specification, the elapsed time is sometimes referred to as AT.

In this way, the relay device 21 judges whether the stored data stored in the memory unit 11 is valid or not based on the AT. Stored data that is judged to be valid based on the AT can be said to be data that is guaranteed to have a certain level of freshness. Then, the relay device 21 is capable of returning only stored data that is judged to be valid to the requesting node as a corresponding reply.

The AT has AT-Client, which is the allowable elapsed time specified by the requesting node at the time of the request, AT-Service, which is the allowable elapsed time specified in advance by the request destination node for a particular request, and AT-Default, which is the allowable elapsed time prescribed by the request destination node. Note that in the following explanations and drawings, AT-Client, AT-Service, and AT-Default may be abbreviated as AT-C, AT-S, and AT-D, respectively.

AT-C is a time that is set individually for each request sent by the requesting node. When sending a request, the requesting node assigns an AT-C to the request. AT-S is a time that is set individually for each piece of information requested by a request. AT-D is a time that is set individually for each request receiving node.

As shown in FIG. 10, the setting parameters of AT-D are input to the relay device 21 during configuration, which is executed when the device is started up. AT-D represents the validity time of reply data determined for each connection node. The setting parameters of AT-D input in this manner are stored in the memory unit 11. Note that the setting parameters of AT-D may be stored in a storage device other than the memory unit 11 in which the saved data, which is the corresponding reply, is stored.

Specifically, the AT-D is set based on the following concept. For example, if the relay device 21 needs to provide information provided by the body ECU 6, i.e., reply data, with an accuracy of within 10 ms, the AT-D corresponding to the body ECU 6 is set to 10 ms. In this way, for replies provided by a connection node that requires a relatively high level of real-time performance, such as a body ECU, the period during which the stored data is valid when stored in the memory unit 11 is set to be short. In addition, in this way, for replies provided by a connection node that requires a relatively low level of real-time performance, such as a cloud application, the period during which the stored data is valid when stored in the memory unit 11 is set to be long.

As shown in FIG. 11, relay device 21 communicates with ECUs 3-7 and connection nodes which are cloud application 8, and in addition to inputting and outputting data similar to that of relay device 1, relay device 21 also inputs and outputs the following data. That is, during parameter setting processing, relay device 21 receives AT-S setting parameters from connection node Nb which is the request destination node. AT-S represents the validity time of reply data specified by the request destination node which returns reply data. The AT-S setting parameters input in this manner are stored in memory unit 11. Note that the AT-S setting parameters may be stored in a storage device separate from memory unit 11 which stores the saved data which is the corresponding reply.

Specifically, the AT-S is set based on the following concept. For example, if the trunk door lock status of vehicle 2 needs to be provided to the requesting node with an accuracy of within 10 ms, the AT-S for the trunk door lock status is set to 10 ms. In this way, for replies corresponding to request keys that require a relatively high degree of real-timeness, such as headlight status, the period during which the stored data is valid when stored in memory unit 11 is set to be short. In addition, in this way, for replies corresponding to request keys that require a relatively low degree of real-timeness, such as GPS location information, the period during which the stored data is valid when stored in memory unit 11 is set to be long.

In the above configuration, the setting parameters of the AT-D set in the relay device 21 during configuration have the data structure shown in FIG. 12. That is, the setting parameters of the AT-D are linked to the connection node and the AT-D. Also, in the above configuration, the setting parameters of the AT-S notified to the relay device 21 during the parameter setting process have the data structure shown in FIG. 13. That is, the setting parameters of the AT-S are linked to the request key and the AT-S.

In the above configuration, the request exchanged between connection nodes and received by the relay device 21 has a data structure, for example, as shown in FIG. 14. That is, the request includes a request key and an AT-C. The AT-C indicates the validity time of the reply data specified by the request source node that sends the request. Specifically, the AT-C is set based on the following concept. For example, if the meter ECU 4 that sends the request wants to obtain the trunk door lock status of the vehicle 2 with an accuracy of within 10 ms, the AT-C in the request is set to 10 ms. Note that the AT-C in the request can be omitted.

In the above configuration, the stored data, which is the reply relayed by the relay device 21 and stored in the memory unit 11, has a data structure, for example, as shown in FIG. 15. That is, the stored data includes a request key, reply data, and reply time. The reply time is time data corresponding to the time when the reply was relayed, that is, the time when the relay device 21 received the reply.

In the above configuration, the management table stored in the memory unit 11 has data such as that shown in FIG. 16, for example. The management table stores AT-D and AT-S. As described above, AT-D is set during configuration, and AT-S is set during the parameter setting process. The setting parameters for AT-S notified by the connection node are dynamically registered as AT-S in the management table. The AT-D management table associates the connection node with the value of AT-D.

Specifically, the AT-D value of the cloud application 8 is 1000 ms, the AT-D values of the ADASECU 3, meter ECU 4 and navigation ECU 5 are 100 ms, and the AT-D value of the body ECU 6 is 10 ms. The AT-S management table associates request keys with AT-S values. Specifically, the AT-S value of the GPS location information is 100 ms, the AT-S value of the cloud application status is 1000 ms, the AT-S value of the trunk door lock status is 50 ms, and the AT-S value of the headlight status is 20 ms.

The connection nodes, which are the ECUs 3 to 7 and the cloud application 8, are configured to notify the relay device 21 of the AT-S setting parameters that correspond to the reply that they provide. Such notifications can be sent at any time. When the relay device 21 receives such notifications, it is configured to update the received AT-S setting parameters in the aforementioned management table as needed.

Next, the parameter setting process executed by the relay device 21 configured as above will be described with reference to FIG. 17. The relay device 21 is configured to repeatedly execute the parameter setting process shown in FIG. 17 at a predetermined cycle. First, in step S201, the relay device 21 receives the AT-S setting parameters notified from the connection node. After executing step S201, the process proceeds to step S202. In step S202, the AT-S setting parameters received in step S201 are registered in the management table. After executing step S202, this process ends.

Next, the process flow related to the relay of communication executed by the relay device 21 configured as above will be described with reference to Figs. 17 and 18. Note that the relay device 21 is configured to repeatedly execute the process shown in Fig. 17, that is, the request-reply relay process, at a predetermined cycle. The relay process of this embodiment shown in Fig. 17 differs from the relay process of the first embodiment shown in Fig. 6 in that steps S201 and S202 are added.

In the relay process of this embodiment, if a corresponding reply exists in the memory unit 11, the result in step S102 becomes "YES" and the process proceeds to step S201. In step S201, an AT setting process is executed. The AT setting process is a process for setting one of AT-D, AT-S, and AT-C as the AT to be used in the judgment in step S202, and has the contents as shown in FIG. 18.

As shown in FIG. 18, when the AT setting process is started, step S301 is executed first. In step S301, it is determined whether or not an AT-C has been assigned to the received request. If an AT-C has been assigned to the received request, step S301 becomes "YES" and the process proceeds to step S302. In step S302, the AT-C is set as the AT. On the other hand, if an AT-C has not been assigned to the received request, step S301 becomes "NO" and the process proceeds to step S303.

In step S303, it is determined whether or not an AT-S corresponding to the information requested by the received request, i.e., the request key included in the received request, exists in the management table. If an AT-S corresponding to the request key included in the received request exists in the management table, step S303 becomes "YES" and the process proceeds to step S304. In step S304, the AT-S is set as the AT. On the other hand, if an AT-S corresponding to the request key included in the received request does not exist in the management table, step S303 becomes "NO" and the process proceeds to step S305. In step S305, an AT-D is set as the AT. After step S305 is executed, the process returns.

When returning from the AT setting process, the process proceeds to step S107, where stored data corresponding to the corresponding reply is retrieved from the memory unit 11. After execution of step S107, the process proceeds to step S202. In step S202, using the AT set in step S201, it is determined whether or not the stored data retrieved in step S107 is valid. This determination is made based on whether or not the following formula (1) is satisfied. Here, the reply time included in the stored data is denoted as Tr, and the current time is denoted as Tc.
Tr<Tc-AT...(1)

If the above formula (1) is satisfied, the time that has elapsed from the reply time Tr of the stored data to the current time Tc is within the AT, and therefore the stored data can be determined to be valid. If the above formula (1) is not satisfied, the time that has elapsed from the reply time Tr of the stored data to the current time Tc exceeds the AT, and therefore the stored data can be determined to be invalid.

If the above (1) is satisfied, step S202 becomes "YES" and the process proceeds to step S108, where the stored data corresponding to the corresponding reply extracted in step S107 is returned to the request source node as a reply corresponding to the request to be relayed. On the other hand, if the above (1) is not satisfied, step S202 becomes "NO" and the process proceeds to step S103, where the request to be relayed is sent to the request destination node. After step S103 is executed, steps S104 to S106 are executed in sequence. After step S106 or S108 is executed, this process ends.

Next, the operation of the relay device 21 when communication is performed between the connection nodes in the above configuration will be described with reference to the specific examples shown in Figures 20 to 23. Note that the specific examples shown in Figures 20 to 23 represent communication when the meter ECU 4 obtains the trunk door lock status from the body ECU 6.

[1] When a relay device relays communication and returns a reply, as shown in Fig. 20, when the relay device 21 receives a request including a request key indicating the "trunk door lock status" transmitted from the meter ECU 4, it determines whether or not it is possible to return the data stored in the memory unit 11 as a reply. In this case, it is assumed that there is no valid corresponding reply in the memory unit 11. Therefore, the relay device 21 transfers the request as is to the body ECU 6, which is the request destination node.

After that, when the relay device 21 receives a reply corresponding to the request key from the body ECU 6, which is the request destination node, the relay device 21 relays the reply to the meter ECU 4, which is the request source node. At this time, the relay device 21 adds a reply time to the relayed reply and stores it as saved data in the memory unit 11, that is, it executes the storage process described above.

[2] When the relay device does not relay communication and returns a reply using AT-C As shown in Fig. 21, when the relay device 21 receives a request including a request key indicating the "trunk door lock status" transmitted from the meter ECU 4, the relay device 21 judges whether or not the request has an AT-C attached thereto. If the request has an AT-C attached thereto, the relay device 21 judges whether or not the data stored in the memory unit 11 can be returned as a reply using the AT-C.

In this case, it is assumed that a corresponding reply exists in the memory unit 11 and that the elapsed time from the reply time of the corresponding reply to the current time is within the value of AT-C. Therefore, the relay device 21 retrieves the stored data stored in the memory unit 11 and transfers the stored data as a reply to the meter ECU 4, which is the request source node, in other words, it executes the return process described above. In this case, the body ECU 6, which is the request destination node, does not execute any operations related to communication.

[3] When the relay device does not relay communication and returns a reply using AT-S As shown in Fig. 22, when the relay device 21 receives a request including a request key indicating the "trunk door lock status" transmitted from the meter ECU 4, the relay device 21 judges whether or not an AT-C is attached to the request. If an AT-C is not attached to the request, the relay device 21 judges whether or not an AT-S corresponding to the request key included in the request exists in the management table.

If an AT-S corresponding to the request key exists in the management table, it is determined whether the data stored in the memory unit 11 can be returned as a reply using the AT-S. In this case, it is assumed that a corresponding reply exists in the memory unit 11 and the elapsed time from the reply time of the corresponding reply to the current time is within the value of the AT-S. Therefore, the relay device 21 retrieves the stored data stored in the memory unit 11 and transfers the stored data as a reply to the meter ECU 4, which is the request source node, in other words, it executes the return process described above. In this case, the body ECU 6, which is the request destination node, does not execute any operations related to communication.

[4] Case where the relay device does not relay communication and uses AT-D to return a reply As shown in Fig. 23, when the relay device 21 receives a request including a request key indicating "trunk door lock status" transmitted from the meter ECU 4, it determines whether or not an AT-C is attached to the request. If an AT-C is not attached to the request, the relay device 21 determines whether or not an AT-S corresponding to the request key included in the request exists in the management table. If an AT-S corresponding to the request key does not exist in the management table, it determines whether or not the data stored in the memory unit 11 can be returned as a reply using AT-D.

Which of the multiple AT-D values in the management table is used depends on the request destination node. In this case, the request destination node is the body ECU 6, so the AT-D corresponding to the body ECU 6 is used. In this case, it is assumed that a corresponding reply exists in the memory unit 11 and that the elapsed time from the reply time of the corresponding reply to the current time is within the value of AT-D. Therefore, the relay device 21 retrieves the stored data stored in the memory unit 11 and transfers the stored data as a reply to the meter ECU 4, which is the request source node, in other words, it executes the return process described above. In this case, the body ECU 6, which is the request destination node, does not execute any operations related to communication.

According to the present embodiment described above, in addition to the same effects as those of the first embodiment, the following effects can be obtained.
In the above configuration, when the storage processing unit 23 executes the storage process, it assigns the reply time to the reply and stores it, and the relay processing unit 24 executes the return process if the elapsed time from the reply time of the corresponding reply to the current time is within a predetermined AT, and executes the relay process of sending a relay corresponding request to the request destination node if the elapsed time of the corresponding reply exceeds the AT. In other words, in the above configuration, the relay processing unit 24 uses the AT to determine whether the corresponding reply is valid or not, executes the return process if the corresponding reply is valid, and executes the relay process if the corresponding reply is invalid.

In this way, when the relay device 21 returns stored data equivalent to the corresponding reply stored in the memory unit 11 to the request source node without relaying communication, the corresponding reply can be guaranteed to be up-to-date at a certain level. In other words, with the above configuration, when the relay device 21 returns stored data equivalent to the corresponding reply stored in the memory unit 11 to the request source node without relaying communication, the real-time nature of the corresponding reply can be ensured at a desired level.

The AT includes AT-D, which is a time set individually for each request destination node, AT-S, which is a time set individually for each piece of information requested by a request, and AT-C, which is a time set individually for each request sent by the requesting node. When the relay device 21 uses AT-D to determine the validity of a corresponding reply, it can guarantee a predetermined level of real-timeness for each connected node for the corresponding reply sent back to the requesting node.

In addition, when relay device 21 uses AT-S to determine the validity of a corresponding reply, the requested node can specify the level of real-timeness guaranteed for the corresponding reply returned to the requesting node.In addition, when relay device 21 uses AT-C to determine the validity of a corresponding reply, the requesting node can specify the level of real-timeness guaranteed for the corresponding reply returned to the requesting node each time it sends a request.

Of AT-D, AT-S and AT-C, AT-C is the time that is most specifically defined for each piece of information requested by the request, followed by AT-S as the most specifically defined time, and AT-D as the most roughly defined time. In this case, the priority used to determine validity for AT-D, AT-S and AT-C is AT-C with the highest priority, AT-S with the second highest, and AT-D with the lowest. In this way, it is possible to determine the validity of the corresponding reply by preferentially using the AT that is specifically defined for each piece of information requested by the request, and therefore it is possible to more reliably guarantee the desired level of real-timeness of the corresponding reply.

Other Embodiments
The present invention is not limited to the embodiments described above and shown in the drawings, and can be modified, combined, or expanded as desired without departing from the spirit and scope of the present invention.
The numerical values and the like shown in the above embodiments are merely examples and are not intended to be limiting.
The present invention is not limited to the relay devices 1 and 21 used in the communication system of the vehicle 2, but can be applied to any relay device that relays communication between a plurality of connection nodes that perform request-reply type information acquisition communication.

Although the present disclosure has been described with reference to the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and concept of the present disclosure.

The control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by combining a processor and a memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by the computer.

1, 21... relay device, 3-7... ECU, 8... cloud application, 11... storage unit, 14, 23... storage processing unit, 15... judgment processing unit, 16, 24... relay processing unit.

Claims (2)

A relay device that relays communication between a plurality of connection nodes (3 to 8) that perform request-reply type information acquisition communication,
The connection node that transmits a request for requesting information acquisition is defined as a request source node, and the connection node that receives the request and returns a reply including the information requested by the request source node to the request source node is defined as a request destination node.
A memory unit (11) capable of storing the reply;
a storage processing unit (14, 23) that executes a storage process for storing the reply in the storage unit when the reply is relayed from the request destination node to the request source node;
a determination processing unit (15) that executes a determination process to determine whether or not a corresponding reply, which is the reply corresponding to a relay target request, which is the request to be relayed, exists among the replies stored in the storage unit when relaying the request transmitted from the request source node to the request destination node;
a relay processing unit (16, 24) that executes a return process of returning the corresponding reply stored in the storage unit to the request source node as the reply to the relay target request without transmitting the relay target request to the request destination node when the corresponding reply exists;
Equipped with
When executing the storage process, the storage processing unit (23) is configured to add a reply time, which is a time corresponding to a time when the reply was relayed, to the reply and store the reply,
The relay processing unit (24)
determining whether the corresponding reply is valid based on whether an elapsed time from the reply time of the corresponding reply to a current time is within a predetermined elapsed allowable time;
If the elapsed time of the corresponding reply is within the elapsed time limit and the corresponding reply is determined to be valid, the return process is executed;
If the elapsed time of the corresponding reply exceeds the permitted elapsed time and the corresponding reply is determined to be invalid, a relay process is executed to transmit the request to be relayed to the request destination node;
The allowable elapsed time includes AT-D, which is a time individually set for each of the request destination nodes, AT-S, which is a time individually set for each of the information requested by the request, and AT-C, which is a time individually set for each of the requests transmitted by the request source node,
the request source node is adapted to attach the AT-C to the request when transmitting the request,
A relay device in which priorities are determined for the AT-D, the AT-S, and the AT-C to be used in determining whether the corresponding reply is valid . The relay device according to claim 1, wherein the memory processing unit is configured to delete a reply corresponding to the same request as the relayed reply if the reply corresponding to the same request as the relayed reply is stored in the memory unit when the memory processing unit executes the storage process.

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