JP2003264571A - Gateway and relay method for communication data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a bus load in a communication network having a gateway for relaying communication among a plurality of communication bases. <P>SOLUTION: A gateway for transferring data through a plurality of communication buses with a terminal, detects a terminal being the destination of data 11 in data frames 10 received through buses A to C, and transmits the data 11 only to a bus D to which a terminal D1 being the destination of the received data 11 is connected among a plurality of communication buses. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gateway for relaying communication data and a communication data relay method, which is suitable for use in, for example, an in-vehicle LAN.

[0002]

2. Description of the Related Art Conventionally, in a communication network, in order to cope with the bloat of the network and the diversification of communication protocols, a node connecting to the network, that is, a gateway that relays communication between terminals and performs protocol conversion, A so-called device is used.

For example, in a vehicle, ECUs of various parts of the vehicle communicate as terminals through a communication network called an in-vehicle LAN. This in-vehicle LAN is composed of buses that differ for each communication protocol, and communication over a plurality of buses is relayed by a gateway.

[0004]

In such a communication network in which the gateway relays the communication,
Bus occupancy of a data frame, which is a set of communication data,
That is, when the bus load becomes large, the data transmission delay phenomenon frequently occurs, and in the worst case, the data frame is not delivered,
That is, a frame omission may occur. Therefore, keeping the bus load low is an important factor for improving the reliability of communication.

In a general network design method, it is possible to reduce the number of terminals per bus by increasing the number of buses such as using a plurality of buses with the same communication protocol. By doing so, the load on the bus is reduced, but on the other hand, the increase in the number of buses leads to complication, enlargement, and cost increase of the network.

In view of the background described above, the present invention has an object to reduce bus load in a communication network having a gateway for relaying communication between a plurality of communication buses.

[0007]

In order to achieve the above object, the invention according to claim 1 is a bus means for exchanging data with a terminal via a plurality of communication buses, and a receiving means via a communication bus. A destination detecting unit that detects a terminal that is a destination of the received data, and a data transmitting unit that transmits the data only to a communication bus of the plurality of communication buses to which the terminal that is the destination of the received data is connected. It is a gateway equipped.

As a result, the gateway, which exchanges data with the terminals via the plurality of communication buses, detects the destination terminal of the data received via the communication buses, and the terminal as the destination of the data connects. Since the data is sent only to the existing communication bus, unnecessary data is not sent to the communication bus. Therefore, the bus load can be reduced in a communication network having a gateway that relays communication between a plurality of communication buses.

Further, in the invention described in claim 2, in the gateway described in claim 1, the data transmission means is:
It is characterized in that the data received via the communication bus is collected as a data frame which is a set of data based on the terminal which is the destination of each data, and then the data frame is sent to the communication bus.

Further, in the invention described in claim 3, in the gateway described in claim 1 or 2, the identifier of the data frame, which is a set of data received via the communication bus, and each data in the data frame. The destination detecting means reads the identifier of the received data frame, and becomes the destination of each data in the data frame based on the identifier and the recording of the recording means. It is characterized by detecting the terminal.

Further, in the invention described in claim 4, in the gateway described in claim 1 or 2, the destination detection means indicates a destination terminal recorded in the data received via the communication bus. It is characterized in that the information is read and the terminal which is the destination of the data is detected based on the information indicating the destination terminal.

Further, according to the invention of claim 5, in a gateway for exchanging data with a terminal via a plurality of communication buses, a terminal as a destination of data received via the communication bus is detected, and a plurality of terminals are detected. This is a relay method of communication data in which data is transmitted only to a communication bus connected to a terminal which is a destination of received data among the communication buses.

As a result, the gateway, which exchanges data with the terminals via the plurality of communication buses, detects the terminal which is the destination of the data received via the communication buses, and the terminal which is the destination of the data is connected. Since the data is sent only to the existing communication bus, unnecessary data is not sent to the communication bus. Therefore, the bus load can be reduced in a communication network having a gateway that relays communication between a plurality of communication buses.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIG. 1 shows the configuration of an in-vehicle LAN 1 according to this embodiment. In-car LAN1
Is a gateway 2, buses A to D, nodes A1 to A4,
Nodes B1 to B4, nodes C1 to C4, nodes D1 to D
It is composed of 4. A node is a terminal, which is realized as an ECU in the vehicle in this embodiment.

The bus A is a bus in which communication is performed by a communication protocol for the ECU of the traveling system in the vehicle, for example, CAN. The bus A has nodes A1, A2,
The nodes A3 and A4 are connected. Also bus A
Mediates the transfer of data between these nodes A1 to A4 and the gateway 2. As these nodes, that is, terminals, for example, an engine ECU, an air suspension ECU,
There is a brake ECU and the like. The engine ECU is an ECU that detects the state of the engine, sends it to the bus A, and receives a signal from the bus A to control the engine. The air suspension ECU is an ECU that detects the state of the air suspension, sends it to the bus A, and receives a signal from the bus A to control the air suspension. Brake ECU
Is an ECU that detects the state of the brake, sends it to the bus A, and receives a signal from the bus A to control the brake.

The buses B and C are body-type ECUs.
Communication protocol for, for example, BEAN (Body Elect
rons Area Network) is a bus used for communication. The bus B has nodes B1, B2, B
3 and the node B4 are connected, and the node C is connected to the bus C.
1, node C2, node C3, and node C4 are connected. The bus B includes nodes B1 to B4 and a gateway 2
Mediates the transfer of data to and from
Data is exchanged between the gateways 1 to C4 and the gateway 2. As these nodes, that is, terminals, for example, door ECU, wiper ECU, power window EC
U, light ECU, various switch ECU, horn ECU
Etc. These ECUs detect the states of doors, wipers, power windows, lights, various switches, and horns, respectively, and send them to the bus B or the bus C, and also receive signals from the bus B or the bus C to receive the respective devices. Is an ECU for controlling the.

The bus D is a bus for performing communication by a communication protocol for the ECU of the information system in the vehicle, for example, AVC-LAN. Nodes D1, D2, D3, and D4 are connected to the bus D. Further, the bus D mediates the transfer of data between the nodes D1 to D4 and the gateway 2. Examples of these nodes, that is, terminals include a car navigation ECU, an audio ECU, a wireless telephone ECU, and the like. The car navigation ECU
It is an ECU that receives the control signal from the bus D to acquire the current position of the vehicle using GPS and sends the current position information of the vehicle to the bus D. Audio ECU
Detects the status of the audio device and sends it to bus D,
The ECU also receives a control signal from the bus D and controls the audio device. The wireless telephone ECU is an ECU that receives a control signal and wireless communication data from the bus D, performs wireless communication, and sends the data obtained by wireless communication to the bus D.

FIG. 2 is a block diagram showing the configuration of the gateway 2. The gateway 2 has a CPU 21 and a ROM
22, RAM 23, LAN controllers 24A-24
D and drivers 25A to 25D.

The driver 25A is adapted to receive data from the bus A and output it to the LAN controller 24A, and to receive data from the LAN controller 24A and output it to the bus A.

The driver 25B receives data from the bus B and outputs it to the LAN controller 24B, and also receives data from the LAN controller 24B and outputs it to the bus B.

The driver 25C receives data from the bus C and outputs it to the LAN controller 24C, and also receives data from the LAN controller 24C and outputs it to the bus C.

The driver 25D is adapted to receive the data from the bus D and output it to the LAN controller 24D, and also to receive the data from the LAN controller 24D and output it to the bus D. That is, the drivers 25A to 25D are communication interfaces.

The LAN controller 24A is a driver 2
5A, the data according to the communication protocol of the bus A is received, the data is converted into data that the CPU 21 can handle, and the data is output to the CPU 21. Further, the LAN controller 24A receives the data from the CPU 21, converts the data into data in accordance with the communication protocol of the bus A,
It is output to the bus A.

The LAN controller 24B is a driver 2
The data received from 5B according to the communication protocol of the bus B is received, converted into data that can be handled by the CPU 21, and output to the CPU 21. Further, the LAN controller 24B receives the data from the CPU 21, converts the data into data in accordance with the communication protocol of the bus B,
It is output to the bus B.

The LAN controller 24C is a driver 2
The data received from the 5C according to the communication protocol of the bus C is received, converted into data that can be handled by the CPU 21, and output to the CPU 21. Further, the LAN controller 24C receives the data from the CPU 21, converts the data into data according to the communication protocol of the bus C,
It is output to the bus C.

The LAN controller 24D is a driver 2
The data received from the 5D according to the communication protocol of the bus D is received, converted into data that can be handled by the CPU 21, and output to the CPU 21. Further, the LAN controller 24D receives the data from the CPU 21, converts the data into data according to the communication protocol of the bus D,
It is output to the bus D.

The CPU 21 reads out predetermined software for processing from the ROM 22 and performs processing based on the software. Through the processing, data is received from the LAN controllers 24A to 24D, these data are reorganized according to predetermined processing, and output to the LAN controllers 24A to 24D. Details of the reception, reorganization, and output processing will be described later.

The ROM 22 is a read-only memory including a non-volatile memory. This ROM 22 has a CPU
Predetermined software for 21 to perform processing, and a conversion table and a transmission cycle table described later are recorded.

The RAM 23 is a read / write memory. The RAM 23 is a buffer area for temporarily storing the data received by the CPU 21. In the RAM 23, the CPU 21 reorganizes the data,
This is a buffer area for temporarily storing transmission data so as to be transmitted at a predetermined timing.

By the gateway 2 having such a configuration, the data received by the gateway 2 from one bus is passed to the driver → LAN controller → CPU 21, and the data reorganized by the CPU 21 is CP.
Passed to U21 → LAN controller → driver,
It will be output to a predetermined bus.

In the in-vehicle LAN 1 having such a configuration, communication between terminals is performed in units of data frames which are a collection of data. That is, the terminal transmits data in the form of a data frame and receives data in the form of a data frame. An ID, which is an identifier for identifying the type of the data frame, is stored at the head of the data frame, and a plurality of data are stored following the ID. In one data frame transmitted from a terminal, data of different destination terminals are mixed.

Which terminal in the data frame is to which data is addressed is preliminarily defined by the ID of the data frame. Each terminal sends out a data frame according to this regulation. FIG. 3 shows a part of a table showing the correspondence between the ID of the data frame transmitted from the terminal on the in-vehicle LAN 1 and the destination terminal for each position of the data in the data frame having each ID, that is, a conversion table. . According to FIG. 3, for example, in a data frame having an ID of 002, the first data is addressed to node B2, node B3, the second data is addressed to node C2, and the third data is addressed to node B.
The third data and the fourth data are addressed to the node D3, .... This conversion table is recorded in the ROM 22 described above.

In the present embodiment, the gateway 2 reorganizes the data received from each terminal based on this conversion table, thereby collecting a set of data in which only the data addressed to one terminal is stored as a data frame, and The operation of transmitting the data frame to the terminal is performed.

FIG. 4 schematically shows a data flow in the operation of the in-vehicle LAN 1. Horizontal rectangles on the buses A, B, and C connected to the gateway 2 are data frames transmitted from the terminals on the buses. Each data in this data frame is represented by a vertically long rectangle.
In each of the data, the rectangle filled with black is the data addressed to the node D1. These data frames are received by the gateway 2 and the data addressed to the node D1 are combined into one data frame, which is transmitted to the bus D. A horizontally long rectangle on the bus D in the figure corresponds to this data frame. In this data frame, the black-painted portions are the data addressed to the node D1. The other part is an empty area in the data frame.

In addition, the terminal that receives the data generally updates the information that it possesses by receiving the data. Some information needs to be updated in a short time period, and some information may be updated in a relatively long time period. As described above, the data transmitted from the terminal via the gateway 2 has a predetermined time period that must be transmitted. Therefore, in this embodiment, the type of the format of the data frame created and transmitted by the gateway 2 is determined in advance.
Then, the data to be transmitted to one terminal is further classified according to the transmission cycle, and the type of the data frame of the storage destination is provided for each classification. That is, each piece of data transmitted from the terminal has a destination data frame to be stored when it is reorganized in the gateway 2.
Will correspond.

FIG. 5 is a part of a table in which the destination terminal, the ID of the data frame, and the transmission cycle are associated with each other for each type of data frame provided in this way. This transmission cycle is the shortest of the cycles required to update the data in each data frame. Hereinafter, this table will be referred to as a transmission cycle table. This transmission cycle table is recorded in the ROM 22 described above.

Further, in the ROM 22, the correspondence between each data and the ID of the data frame transmitted by the gateway 2 in which the data is to be stored is also predetermined and recorded.

FIG. 6 shows the gateway 2 when a terminal in a bus transmits data to a terminal in another bus via the gateway 2 in the in-vehicle LAN 1 having such a configuration.
5 is a flowchart showing a procedure of processing performed by the CPU 21 of FIG. Reception of data of the gateway 2 according to this figure,
The operations of reorganization and transmission will be described.

First, in step 600, when the gateway 2 is activated, the CPU 21 is initialized. And C
The PU 21 reads predetermined software from the ROM 22 and starts processing based on this software.

Next, the process proceeds to step 610, where the CPU
21 determines whether or not a data frame is newly received from each bus.

If it is determined that the data has been received, the process proceeds to step 6
20, the CPU 21 reads the conversion table recorded in the ROM 22, and the I of the received data frame is read.
From D, the terminal which is the destination of each data in this data frame is referred to and detected. Further, the ID of the data frame in which each data is to be stored is detected by referring to the ROM 22. Then, in step 630, based on the information detected by reference, the data is written in the data frame for transmission stored in the RAM 23 as buffer data. If the data frame in which the data is to be stored does not exist in the RAM 23, it is created. Then, the process proceeds to step 640.

If it is determined in step 610 that there is no newly received data frame, the process proceeds to step 6
Move to 40.

Then, in step 640, the CPU 21 reads the transmission cycle table recorded in the ROM 22. Then, in step 650, the transmission cycle of each data frame described in this table is compared with the time elapsed since this data frame was last transmitted, and the data whose elapsed time is equal to or longer than the transmission cycle is compared. Determine whether there is a frame.

If it is determined that there is, the CPU 21 sends the data frame only to the bus in which the destination terminal exists. As a result, this data frame is output to a predetermined bus via the LAN controller and driver, and finally received by a predetermined terminal. And the process is 6
Return to 10.

If it is determined that there is not, the process returns to 610,
It is again determined whether or not there is a newly received frame.

By the CPU 21 performing such processing, the gateway 2 detects the terminal which is the destination of the data in the data frame received via the buses A to D, and reorganizes the data. Since the data is sent only to the communication bus to which the terminal that is the destination of the data is connected, unnecessary data is not sent to the communication bus. Therefore, the bus load can be reduced in a communication network having a gateway that relays communication between a plurality of communication buses.

(Second Embodiment) Here, as a second embodiment of the present invention, a terminal which is a destination of data received by the gateway 2 in the in-vehicle LAN 1 having the same structure as that described in the first embodiment. Another method of detecting is described.

In this embodiment, the RAM 23, the LAN controllers 24A to 24D, the drivers 25A to 25D, and the buses A to D of the gateway 2 have the same structure and operation as those of the first embodiment. Omit it.

Further, the CPU 21 and the ROM 22 have the same configurations as those of the first embodiment, and therefore their explanations are omitted. However, the ROM 22 does not have the conversion table described in the first embodiment.

FIG. 7 shows the structure of the data frame transmitted from the terminal in this embodiment. A data frame, which is a collection of data, has an ID, which is an identifier for identifying the type of the data frame, stored at the beginning, and a plurality of data are stored following the ID. In one data frame transmitted from the terminal,
Data of different destination terminals are mixed. Information indicating the terminal that is the destination of the data is stored at the rear of each data. Which position in the data frame the data is destined for is determined by the information following the data.

In the present embodiment, the gateway 2 reorganizes the data received from each terminal with the information indicating the destination terminal following the data, and as a result, a set of data in which only the data addressed to one terminal is stored. Are collected as a data frame, and the data frame is transmitted to the terminal.

FIG. 8 shows that in the in-vehicle LAN 1 having such a configuration, when a terminal in one bus transmits data to a terminal in another bus via the gateway 2, the gateway 2
5 is a flowchart showing a procedure of processing performed by the CPU 21 of FIG. Reception of data of the gateway 2 according to this figure,
The operations of reorganization and transmission will be described. However, in this flowchart, the processing equivalent to that of the flowchart shown in FIG. 6 as the first embodiment will be simplified.

First, step 800 and step 810.
Initialization up to and determination of whether there is a received frame or not
This is equivalent to the processing of steps 500 and 510 in FIG.

If it is determined in step 810 that the data has been received, the process proceeds to step 820, and the CPU 21 reads the data in the received data frame and the information indicating the subsequent destination terminal, and determines the destination terminal of each data. Detect. Further, the ID of the data frame in which each data is to be stored is detected by referring to the record in the ROM 22.
Then, in step 830, based on the detected information, the data is written in the data frame for transmission stored in the RAM 23 as buffer data.
If the data frame in which the data is to be stored does not exist in the RAM 23, it is created. Then, the process proceeds to step 840.

If it is determined in step 810 that there is no newly received data frame, the process proceeds to step 8
Move to 40.

The processing such as determination of the transmission cycle elapse and transmission in steps 840, 850 and 860 are performed in step 6 in FIG.
This is equivalent to the processing of 40, 650, and 660.

By the CPU 21 performing such processing, the gateway 2 detects the terminal which is the destination of the data in the data frame received via the buses A to D, and reorganizes the data, Since the data is sent only to the communication bus to which the terminal that is the destination of the data is connected, unnecessary data is not sent to the communication bus. Therefore, the bus load can be reduced in a communication network having a gateway that relays communication between a plurality of communication buses.

In the first and second embodiments of the present invention, the LAN controllers 24A to 24D and the drivers 25A to 25D for exchanging data between the CPU 21 and the bus A constitute the bus means. However,
The bus means does not have to be realized by a plurality of hardware devices in this way, and may be any means as long as it exchanges data with the terminal via a plurality of communication buses. For example, one general-purpose processing device has a function of performing communication processing with a plurality of communication buses,
It may be realized by software.

Further, in the first embodiment of the present invention,
The process of referring to the destination terminal from the conversion table of step 620 of the CPU 21 to detect the destination terminal constitutes the destination detecting means.
Further, in the second embodiment, the process of detecting the destination terminal in the data frame of step 820 of the CPU 21 constitutes the destination detecting means. However, the destination detection means does not have to be realized by software in this way, and may detect the terminal that is the destination of the data received via the communication bus. For example, it may be realized by a device that detects a destination terminal with dedicated hardware.

Further, in the first embodiment, the CPU 2
The processing from frame reorganization to transmission in steps 630 to 660 of 1 constitutes data transmission means. Further, in the second embodiment, step 8 of the CPU 21
The processing from frame reorganization to transmission in 30 to 860 constitutes data transmission means. However, the data sending means does not have to be realized by software in this way, and can send the data only to the communication bus to which the terminal that is the destination of the received data is connected among the plurality of communication buses. I wish I had it. For example, equivalent processing functions may be configured by dedicated hardware.

Further, in the first and second embodiments, the data frame transmitted by the gateway 2 always includes only the data addressed to a single terminal, but this is always the case. Need not be
Each data frame may be created so as to send data only to the communication bus to which the terminal, which is the destination of the data received by the gateway, is connected among the communication buses. For example, the data addressed to the nodes D2 and D3 may be collected as one data frame, and then this data frame may be transmitted to the bus D.

Further, in the first and second embodiments, the non-volatile ROM 22 in which the conversion table is recorded constitutes the recording means. However, what if the recording means records the correspondence between the identifier of the data frame, which is a set of data received via the communication bus, and the terminal that is the destination of each data in the data frame? It does not have to be a non-volatile memory like this. For example, it may be configured by a volatile memory having a backup power source.

Further, although the communication network described in the first embodiment is the in-vehicle LAN 1, the scope of application of the present invention is not limited to the in-vehicle LAN, and it is a communication network having a gateway for relaying communication between a plurality of communication buses. Anything will do as long as it is available.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an in-vehicle LAN 1 according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a gateway 2.

FIG. 3 is a diagram showing a part of a conversion table included in a ROM 22.

FIG. 4 is a diagram schematically showing a data flow in the operation of the in-vehicle LAN 1.

FIG. 5 is a diagram showing a part of a transmission cycle table included in ROM 22.

FIG. 6 is a flowchart showing processing performed by a CPU 21 in communication between terminals via the gateway 2.

FIG. 7 is a diagram showing a structure of a data frame transmitted from a terminal in the second embodiment.

FIG. 8 is a flowchart showing processing performed by the CPU 21 in communication between terminals via the gateway 2.

[Explanation of symbols]

1 ... in-vehicle LAN, 2 ... gateway, 21 ... CPU, 2
2 ... ROM 22, 23 ... RAM, 24A to 24D ... LA
N controller, 25A to 25D ... Driver.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Honda             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F term (reference) 5K033 AA03 BA08 CB08 CC01 DA13                       DB18

Claims (5)

[Claims] 1. A bus means for exchanging data with a terminal via a plurality of communication buses, a destination detecting means for detecting a terminal which is a destination of data received via the communication bus, and a plurality of communication buses. A gateway for transmitting the data only to a communication bus connected to a terminal which is a destination of the received data. 2. The data sending means collects the data received via the communication bus as a data frame which is a set of data based on a terminal which is a destination of each data, and then the data frame is associated with the data frame. The gateway according to claim 1, wherein the gateway transmits to a communication bus. 3. A destination is provided with recording means for recording correspondence between an identifier of a data frame, which is a set of data received via the communication bus, and a terminal as a destination of each data in the data frame, 3. The detecting means reads the identifier of the received data frame, and detects the terminal which is the destination of each data in the data frame based on this identifier and the record of the recording means. Gateway described in. 4. The destination detecting means reads the information indicating the destination terminal recorded in the data received via the communication bus, and based on the information indicating the destination terminal of the destination The gateway according to claim 1 or 2, which detects a destination terminal. 5. A gateway for transmitting and receiving data to and from a terminal via a plurality of communication buses, detecting a terminal as a destination of data received via the communication bus, and receiving the received data from the plurality of communication buses. A method of relaying communication data, wherein the data is transmitted only to a communication bus connected to a terminal that is the destination of the data.