JP2007027854A - Communication network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication network system whereby communication between nodes via a gateway can be executed at high speed, the upper limit of the utilizing rate of reception exclusive lines can be set higher, and the line can be effectively utilized up to the upper limit. <P>SOLUTION: The communication network system includes: three or more transmission/reception lines 15, 23, 27 where a plurality of nodes are connected; the reception exclusive lines 16, 24, 28 where any of the nodes connected to at least one of the three or more transmission/reception lines are connected; and the gateway 20 for interconnecting the transmission/reception lines and the reception exclusive lines. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication network system, and more particularly to a communication network system that relays communication data using a gateway.

  For example, in a vehicle, an electronic control unit (hereinafter referred to as “ECU”) of each part of the vehicle communicates as a node via a communication network called an in-vehicle LAN (Local Area Network). Each ECU, which is a node, performs control in accordance with the value of the sensor and the operating state of the in-vehicle device, and exchanges data with other nodes as necessary. When the number of ECUs connected to the in-vehicle LAN increases, in order to reduce the load on the communication line, the communication line is divided, each communication line is connected to the gateway device, and the communication data is relayed by the gateway device. .

  FIG. 1 shows a system configuration diagram of an example of a conventional in-vehicle LAN. In the figure, ECUs 1 and 2 are connected to a transmission / reception line 3, and the transmission / reception line 3 is connected to a gateway (GW) 4. Further, the ECUs 5 and 6 are connected to the transmission / reception line 7, and the transmission / reception line 7 is connected to the gateway 4.

  In Patent Document 1, data communication between buses is waited until request requests from each node connected to the bus are completed, and communication is made to the requested bus via a gateway when the request requests are completed. It describes reducing the network load.

Patent Document 2 describes that a destination bus destination is embedded in data transmitted from a bus connected to a gateway, and the gateway reduces the bus load by transmitting the data only to the bus corresponding to the destination. Has been.
Japanese Patent Application Laid-Open No. 2004-40459 JP 2003-264571 A

  In FIG. 1, for example, when data is transmitted from the ECU 5 to the ECU 1, the delay time in the gateway 4 is several milliseconds. Since a plurality of ECUs 1 and 2 that perform transmission and the gateway 4 are connected to the transmission / reception line 3, it takes 10 msec for the gateway 4 to occupy the transmission / reception line 3, and the total delay time in the gateway 4 is There was a problem of requiring several tens of milliseconds.

  In addition, when communication is performed using a CAN (Controlling Area Network) protocol, which is a standard protocol for in-vehicle LAN standardized by ISO11898, etc., the upper limit of the usage rate of each of the transmission / reception lines 3 and 7 is restricted by X%. There was a problem that the utilization rate could not be increased any more.

  The present invention has been made in view of the above points, and can perform high-speed communication between nodes via a gateway, can set a high upper limit on the utilization rate of a dedicated reception line, and can effectively use up to the upper limit. An object of the present invention is to provide a communication network system.

The communication network system of the present invention includes three or more transmission / reception lines connecting a plurality of nodes,
A reception-only line connected to any of a plurality of nodes connected to at least one transmission / reception line of the three or more;
By having a gateway connecting the transmission / reception line and the reception-only line,
Communication between nodes via the gateway can be performed at high speed, and the upper limit of the utilization rate of the reception-only line can be set high, and the upper limit can be effectively used.

The transmission / reception lines of the communication network system are first, second, and third transmission / reception lines,
The reception-only line is connected to any one of a plurality of nodes connected to the first transmission / reception line and a first reception-only line connected to any of the plurality of nodes connected to the first transmission / reception line. By being a third reception-only line connecting a second reception-only line and any of a plurality of nodes connected to the third transmission / reception line,
By transmitting data received from two transmission / reception lines to one reception-dedicated line at the gateway, efficient data transfer can be performed without the need for special arbitration.

The transmission / reception lines of the communication network system are first, second, and third transmission / reception lines,
The reception-only line is connected to any one of a plurality of nodes connected to the first transmission / reception line and a first reception-only line connected to any of the plurality of nodes connected to the first transmission / reception line. By being the second receive-only line,
By transmitting data received from two transmission / reception lines to one reception-dedicated line at the gateway, efficient data transfer can be performed without the need for special arbitration.

The transmission / reception lines of the communication network system are first, second, and third transmission / reception lines,
The reception-only line is one of a first reception-only line connected to any of a plurality of nodes connected to the first transmission / reception line, and a plurality of nodes connected to the second and third transmission / reception lines. Is a second receive-only line that connects
By transmitting data received from two transmission / reception lines to one reception-dedicated line at the gateway, efficient data transfer can be performed without the need for special arbitration.

  According to the present invention, communication between ECUs via a gateway can be performed at high speed, and the utilization rate of a reception-only line can be set high.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment of Communication Network System>
FIG. 2 is a system configuration diagram of the first embodiment of the communication network system of the present invention. In the figure, ECUs 11, 12, 13, 14 are connected to a transmission / reception line 15, and ECUs 11, 12 are connected to a reception-only line 16. The transmission / reception line 15 and the reception-only line 16 are connected to ports A and B of the gateway (GW) 20. The ECUs 13 and 14 are not connected to the reception-only line 16 because the ECUs 13 and 14 do not need to receive data from other ECUs at high speed.

  The ECUs 21 and 22 are connected to the transmission / reception line 23 and to the reception-only line 24. The transmission / reception line 23 and the reception-only line 24 are connected to the ports C and D of the gateway 20. Further, the ECUs 25 and 26 are connected to a transmission / reception line 27 and to a reception-only line 28. The transmission / reception line 27 and the reception-only line 28 are connected to the ports E and F of the gateway 20.

  Here, only the gateway 20 of the reception-only lines 16, 24, and 28 can be a transmission node. For this reason, arbitration is not necessary for each of the reception-only lines 16, 24, and 28, and the upper limit value of the utilization rate of each of the reception-only lines 16, 24, and 28 can be increased to Y%, which is about twice that of the transmission / reception line.

  In this case, for example, the gateway 20 simply sends a frame of communication data supplied from the ECU 21 or 22 through the transmission / reception line 23 (the upper limit of the utilization rate is X%) to the reception-only line 16 and supplies it to the ECU 11 or 12. Although the utilization rate of the reception-only line 16 is a maximum of X%, the frame of communication data supplied from the ECU 21 or 22 through the transmission / reception line 23 (the upper limit value of the utilization rate is X%) and the transmission / reception line from the ECU 25 or 26 27 (the upper limit value of the utilization rate is X%), the frames of communication data supplied through 27 are combined and sent to the reception dedicated line 16 and supplied to the ECU 11 or 12, thereby increasing the utilization rate of the reception dedicated line 16 to a maximum of Y%, That is, it can be effectively used as the upper limit value of the utilization rate of the reception-only line 16.

<First Embodiment of Gateway Device>
FIG. 3 shows a configuration diagram of the first embodiment of the gateway device 20 of the present invention. This gateway device is a single CPU type. In the figure, a ROM 32 and a RAM 33 are connected as memories to a CPU 31 that controls communication.

  The CPU 31 is connected to LAN controllers 35a to 35f via an internal data bus 34, and the LAN controllers 35a to 35f are connected to ports A to F via drivers 36a to 36f as communication interfaces. As described above, the ports A, C, and E are connected to the transmission / reception lines 15, 23, and 27, and the ports B, D, and F are connected to the reception-only lines 16, 24, and 28.

  The drivers 36a to 36f receive frames of communication data from the transmission / reception lines 15, 23, 27 or the reception dedicated lines 16, 24, 28 and supply them to the LAN controllers 35a to 35f. The drivers 36a, 36c, 36e The frame of communication data supplied from 35c, 35e is sent to the transmission / reception lines 15, 23, 27.

  The LAN controllers 35a to 35f supply the communication data frame received from the port to the CPU 31, and the LAN controllers 35a, 35c, and 35e supply the communication data frame supplied from the CPU 31 to the drivers 36a, 36c, and 36e.

<Functional block of gateway device>
FIG. 4 is a functional block diagram of the gateway device 20 according to the first embodiment of the present invention. In the figure, the frames received by the drivers 36a, 36c, 36e are stored in the reception MBOXs 59a, 59c, 59e in the LAN controllers 35a, 35c, 35e, and passed to the gateway destination distribution process 60 executed by the CPU 31.

  The gateway destination distribution processing 60 distributes the frame supplied from the reception MBOX 59a to the FIFO 61a for the driver 36b or the FIFO 62a for the driver 36d according to the frame destination. Further, the frame supplied from the reception MBOX 59c is distributed to the FIFO 61b for the driver 36b or the FIFO 63a for the driver 36f according to the destination of the frame. Further, the frame supplied from the reception MBOX 59e is distributed to the FIFO 62b for the driver 36d or the FIFO 63b for the driver 36f according to the destination of the frame.

  In the LAN controller 35b, transmission MBOXs 64a and 64b are provided corresponding to the FIFOs 61a and 61b. Similarly, transmission MBOX 65a and 65b are provided corresponding to the FIFOs 62a and 62b in the LAN controller 35d, and transmission MBOXs 66a and 66b are provided corresponding to the FIFOs 63a and 63b in the LAN controller 35f.

  When one frame (for example, the transmission MBOX 64a side) of the frames stored in the transmission MBOX 64a and 64b is sent from the driver 36b to the reception dedicated line 16, the frame from the FIFO 61a to the empty transmission MBOX 64a is sent at the next timing. Is transferred. During this transfer process, the other frame (transmission MBOX 64b side) is sent from the driver 36b to the reception-only line 16. Further, at the next timing, the frame is transferred from the FIFO 61b to the empty transmission MBOX 64b. During this transfer process, one frame (transmission MBOX 64a side) is sent from the driver 36b to the reception-only line 16, and this is repeated.

  As described above, during the transmission process of the frame from the transmission MBOX, the transfer process of the frame from the FIFO to the transmission MBOX is performed on the other side, and it is not necessary to perform a special arbitration between the transmission MBOXs 64a and 64b, which is efficient. Data transfer can be performed.

  On the other hand, when three transmission MBOXs are connected to one driver, frames are transmitted from the first transmission MBOX, and then frames are transmitted from either the second or third transmission MBOX. It is necessary to mediate.

<Flowchart of processing executed by gateway device>
FIG. 5 shows a flowchart of processing executed by the gateway device 20. In the figure, after the initialization process is executed in step S1, it is determined in step S2 whether or not there is a reception frame from the transmission / reception lines 15, 23, 27.

  Only when there is a received frame, the process proceeds to step S3 to determine whether it is a gateway target frame. It is a gateway target frame when the destination ECU is connected to a different LAN from the transmission source ECU. If it is not a gateway target frame, the process proceeds to step S2, and if it is a gateway target frame, gateway destination distribution processing is performed in step S4.

  Next, in step S5, the frame is written and added to the gateway destination FIFO, and in step S6, it is determined whether or not the transmission MBOX is empty. If the transmission MBOX is empty, the frame is transferred from the FIFO to the transmission MBOX in step S7. Thereafter, it is determined whether or not transmission is possible in step S8. If transmission is possible, the transmission MBOX frame is transmitted to the line in step S9, and the process proceeds to step S2.

<Data frame of CAN protocol>
In the CAN protocol used in the in-vehicle LAN system, a data frame having a format shown in FIG. 6 is transmitted from the transmission side ECU to the reception side ECU. The data frame includes an SOF (Start Of Frame) field, an ID (IDentifier) field, a Control field, a CRC (Cyclic Redundancy Check) field, an ACK (ACKnowledge) field, and an EOF (End Of Frame) field.

  Here, the ID field also serves as an arbitration field. When two or more ECUs start transmission at the same time, the ID field is compared in units of 1 bit, and the ECU that has continued to output dominant (priority) for a long time is used. Acquire the transmission right.

<Second Embodiment of Gateway Device>
FIG. 7 shows a configuration diagram of the second embodiment of the gateway device 20 of the present invention. This gateway apparatus has a plurality of types, and is used in the communication network system shown in FIGS. In the figure, ROMs 42 and 52 and RAMs 43 and 53 are connected as memories to CPUs 41 and 51 for controlling communication.

  The CPU 41 is connected to LAN controllers 45a, 45b, and 45e via an internal data bus 44, and the LAN controllers 45a, 45b, and 45e are connected to ports A, B, and E via drivers 46a, 46b, and 46e as communication interfaces. ing. The CPU 51 is connected to the LAN controllers 55c, 55d, and 55e via the internal data bus 54, and the LAN controllers 55c, 55d, and 55e are connected to the ports C, D, and E via drivers 46c, 46d, and 46e as communication interfaces. ing. As described above, the ports A, C, and E are connected to the transmission / reception lines 15, 23, and 27, and the ports B and D are connected to the reception-only lines 16 and 24.

  Drivers 46a, 46c, 46e receive communication data frames from transmission / reception lines 15, 23, 27 and supply them to LAN controllers 45a, 55c, 45e or 55e, and drivers 46b, 46d, 46e provide LAN controllers 55b, 45d, 45e. Alternatively, the communication data frame supplied from 55e is sent to the reception-only lines 16 and 24 or the transmission / reception line 27. The transmission / reception line 27 also serves as the reception-only line 28 in FIG.

  The LAN controllers 45a, 45d, and 45e supply the data received from the ports to the CPU 41, and the LAN controllers 45d and 45e supply the communication data frames supplied from the CPU 41 to the drivers 46d and 46e. The LAN controllers 55b, 55c, and 55e supply the communication data frame received from the port to the CPU 51, and the LAN controllers 55b and 55e supply the communication data frame supplied from the CPU 51 to the drivers 46b and 46e.

<Second Embodiment of Communication Network System>
FIG. 8 shows a system configuration diagram of a second embodiment of the communication network system of the present invention. In the figure, ECUs 11, 12, 13, 14 are connected to a transmission / reception line 15, and ECUs 11, 12 are connected to a reception-only line 16. The transmission / reception line 15 and the reception-only line 16 are connected to ports A and B of the gateway (GW) 20.

  The ECUs 21 and 22 are connected to the transmission / reception line 23 and to the reception-only line 24. The transmission / reception line 23 and the reception-only line 24 are connected to the ports C and D of the gateway 20. Further, the ECUs 25 and 26 are connected to a transmission / reception line 27. The transmission / reception line 27 is connected to the port E of the gateway 20.

  That is, when compared with the first embodiment of the in-vehicle LAN, the reception dedicated line 28 is not provided. In this case as well, only the gateway 20 of the reception-only lines 16 and 24 can be a transmission node. Therefore, arbitration is not required for each of the reception-only lines 16 and 24, and the upper limit value of the utilization rate of each of the reception-only lines 16 and 24 can be increased to Y%, which is about twice that of the transmission / reception line.

  In this case, for example, the gateway 20 simply sends a frame of communication data supplied from the ECU 21 or 22 through the transmission / reception line 23 (the upper limit of the utilization rate is X%) to the reception-only line 16 and supplies it to the ECU 11 or 12. Although the utilization rate of the reception-only line 16 is a maximum of X%, the frame of communication data supplied from the ECU 21 or 22 through the transmission / reception line 23 (the upper limit value of the utilization rate is X%) and the transmission / reception line from the ECU 25 or 26 27 (the upper limit value of the utilization rate is X%), the frames of communication data supplied through 27 are combined and sent to the reception dedicated line 16 and supplied to the ECU 11 or 12, thereby increasing the utilization rate of the reception dedicated line 16 to a maximum of Y%, That is, it can be effectively used as the upper limit value of the utilization rate of the reception-only line 16.

<Third Embodiment of Communication Network System>
FIG. 9 shows a system configuration diagram of the third embodiment of the communication network system of the present invention. In the figure, ECUs 11, 12, 13, 14 are connected to a transmission / reception line 15, and ECUs 11, 12 are connected to a reception-only line 16. The transmission / reception line 15 and the reception-only line 16 are connected to ports A and B of the gateway (GW) 20.

  The ECUs 21 and 22 are connected to the transmission / reception line 23 and to the reception-only line 24. The transmission / reception line 23 and the reception-only line 24 are connected to the ports C and D of the gateway 20. Further, the ECUs 25 and 26 are connected to the transmission / reception line 27 and to the reception-only line 24. The transmission / reception line 27 is connected to the port E of the gateway 20.

  That is, as compared with the first embodiment of the in-vehicle LAN, the ECUs 25 and 26 are connected to the reception dedicated line 24 instead of the reception dedicated line 28. In this case as well, only the gateway 20 of the reception-only lines 16 and 24 can be a transmission node. Therefore, arbitration is not required for each of the reception-only lines 16 and 24, and the upper limit value of the utilization rate of each of the reception-only lines 16 and 24 can be increased to about twice that of the transmission / reception line, for example, Y%.

  In this case, for example, the gateway 20 simply sends a frame of communication data supplied from the ECU 21 or 22 through the transmission / reception line 23 (the upper limit of the utilization rate is X%) to the reception-only line 16 and supplies it to the ECU 11 or 12. Although the utilization rate of the reception-only line 16 is a maximum of X%, the frame of communication data supplied from the ECU 21 or 22 through the transmission / reception line 23 (the upper limit value of the utilization rate is X%) and the transmission / reception line from the ECU 25 or 26 27 (the upper limit value of the utilization rate is X%), the frames of communication data supplied through 27 are combined and sent to the reception dedicated line 16 and supplied to the ECU 11 or 12, thereby increasing the utilization rate of the reception dedicated line 16 to a maximum of Y%, That is, it can be effectively used as the upper limit value of the utilization rate of the reception-only line 16.

It is a system block diagram of an example of the conventional in-vehicle LAN. 1 is a system configuration diagram of a first embodiment of a communication network system of the present invention. It is a block diagram of 1st Embodiment of the gateway apparatus of this invention. It is a functional block diagram in 1st Embodiment of the gateway apparatus of this invention. It is a flowchart of the process which a gateway apparatus performs. It is a data frame format of the CAN protocol. It is a block diagram of 2nd Embodiment of the gateway apparatus of this invention. It is a system configuration | structure figure of 2nd Embodiment of the communication network system of this invention. It is a system block diagram of 3rd Embodiment of the communication network system of this invention.

Explanation of symbols

11, 12, 13, 14, 21, 22, 25, 26 ECU
15, 23, 27 Transmission / reception line 16, 24, 28 Reception-only line 20 Gateway 31 CPU
32 ROM
33 RAM
34 Internal data bus 35a to 35f LAN controller 36a to 36f Driver 59a, 59c, 59e Reception MBOX
61a, 61b, 62a, 62b, 63a, 63b, FIFO
64a, 64b, 65a, 65b, 66a, 66b, reception MBOX

Claims (4)

Three or more transmission / reception lines connecting multiple nodes;
A reception-only line connected to any of a plurality of nodes connected to at least one transmission / reception line of the three or more;
A communication network system comprising a gateway connecting the transmission / reception line and the reception-dedicated line. The communication network system according to claim 1,
The transmission / reception lines are first, second and third transmission / reception lines,
The reception-only line is connected to any one of a plurality of nodes connected to the first transmission / reception line and a first reception-only line connected to any of the plurality of nodes connected to the first transmission / reception line. A communication network system comprising a second reception-only line and a third reception-only line connecting any of a plurality of nodes connected to the third transmission / reception line. The communication network system according to claim 1,
The transmission / reception lines are first, second and third transmission / reception lines,
The reception-only line is connected to any one of a plurality of nodes connected to the first transmission / reception line and a first reception-only line connected to any of the plurality of nodes connected to the first transmission / reception line. A communication network system, wherein the communication network system is a second reception-only line. The communication network system according to claim 1,
The transmission / reception lines are first, second and third transmission / reception lines,
The reception-only line is one of a first reception-only line connected to any of a plurality of nodes connected to the first transmission / reception line, and a plurality of nodes connected to the second and third transmission / reception lines. A communication network system, characterized in that it is a second dedicated line for reception.

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