JP2007135107A - Relay connection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relay connection unit which is connected to a plurality of on-vehicle LANs and allows messages to be exchanged between on-vehicle LANs. <P>SOLUTION: The relay connection unit includes; on-vehicle LAN communication means which are connected to the plurality of on-vehicle LANs respectively and transmit and receive messages; a message selection means which selects and receives messages to be relayed, through respective on-vehicle LAN communication means; message storage means which are interposed between the message selection means and respective on-vehicle LAN communication means to temporarily store messages to be relayed which are sent from the message selection means to respective on-vehicle LAN communication means, in the forms of corresponding queues; and a transmission management means which monitors whether each on-vehicle LAN communication means is in a transmittable state or not and outputs messages stored in message storage means to the on-vehicle LAN communication means when the on-vehicle LAN communication means is in the transmittable state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a relay connection unit, and more specifically, in a system in which a plurality of vehicle-mounted LANs are connected to communicate with each other, high-speed message communication can be reliably performed with a simple hardware configuration.

  In recent years, with the increase in functions of automobiles, the number of electronic control units (ECUs) installed in automobiles also tends to increase. Further, when each ECU is connected by a vehicle control network (hereinafter simply referred to as an in-vehicle LAN network), the number of ECUs connected to the in-vehicle LAN network increases and the amount of data (traffic) to be communicated also increases.

  When the traffic of data transmitted from the ECU to the in-vehicle LAN network increases, the communication load factor of the in-vehicle LAN network increases, and messages including data to be periodically output from the ECU are communicated on the in-vehicle LAN network. The probability of collision with a message increases, and the message transmission interval may be disturbed or the delay time may be increased. Therefore, by dividing the in-vehicle LAN network connecting the ECUs into, for example, several in-vehicle LAN segments for each function, data traffic flowing in each segment can be suppressed. The separated in-vehicle LANs are connected using a relay connection unit such as a gateway.

  As shown in FIG. 8, when performing communication conforming to CAN (Controller Area Network) which is an example of a conventional general in-vehicle LAN, the configuration of the gateway 90 is connected to a plurality of CAN networks 91a and 91b, respectively. CAN communication means 92a, 92b, message selection means 93 for selecting a message having identification information to be relayed among messages received via these CAN communication means 92a, 92b, and 16 different slots, for example. The slot storage means 94 for storing messages having different identification information for each slot, and the relay connection unit 90 as a whole, and the messages stored in the slot storage means 94 are sequentially sent to the CAN communication means 92a and 92b. The output control means 95 and the slot storage means 94 are full. Sometimes it is conceivable consisting RAM96 Metropolitan for temporarily storing the internal information.

  That is, by storing one message in one slot, the message storage means 94 can efficiently distribute and store messages in each slot, so that high-speed processing can be performed.

  Alternatively, as shown in FIG. 9, there is provided transfer target identification information recording means 97 in which identification information of a message to be selected by the message selection means 93 is recorded, and the message to be transferred is displayed in the slot regardless of the identification information. For example, storing in two slots in the storage means 98 is performed alternately.

  Japanese Patent Application Laid-Open No. 5-14353 describes that a FIFO stack is provided to temporarily store a message when a gateway interposed between two in-vehicle LANs cannot transfer data. ing. That is, it is considered to make the slot storage means 98 or the RAM 96 FIFO type.

Japanese Patent Laid-Open No. 5-14353

  However, as in the case of FIG. 8, when the slot storage means 94 having slots divided for each message identification information is formed, it is necessary for each message identification information to be relayed by the gateway 90. Since the slot storage area 94 grows unnecessarily, the configuration of the gateway 90 is complicated, and the memory use efficiency in the slot storage area 94 is extremely poor.

  Therefore, it is conceivable to limit the capacity of the slot storage means 94 to about 16 to 32 slots and assign a plurality of identification information to each slot. In this case, a message having the identification information assigned to the same slot is continued. Therefore, there is a problem that a message stored in the slot is overwritten by a later message. For this reason, as soon as a message enters the slot, it is necessary to interrupt the control means 95 and perform message transfer processing before receiving the next message, which complicates signal processing. For this reason, signal processing using software is performed, which causes a problem that the delay time becomes long.

  On the other hand, when the slot storage means 98 having two slots for alternately storing messages regardless of the identification information is formed as shown in FIG. 9, the messages are alternately stored in different slots, so that they are retained in each slot. Since the available time can be doubled as long as it takes to receive the message, the control means 95 can perform the relay process with a margin. However, since the capacity of the slot storage means 98 is small, it becomes full immediately, and it is necessary to save it in the RAM 96, and there is a problem that the signal processing becomes complicated accordingly. Therefore, in this case as well, it is necessary to perform signal processing using software, which increases the delay time.

  In any of the above examples, as the number of in-vehicle LAN segments connected by the relay connection unit increases, the amount of data to be relayed increases, so that the amount of messages stored in the slot storage means 94 and 98 increases accordingly. There is a concern that the amount will increase and each of the above problems will increase. Therefore, even if a FIFO-type stack is simply provided as in Patent Document 1, if the message needs to be relayed in multiple directions, the information input earlier is simply output first according to the state of the output destination. Sometimes things can't be done.

  The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a relay connection unit that is connected to a plurality of in-vehicle LANs and can exchange messages between the in-vehicle LANs. is there.

In order to solve the above problem, the first invention is:
In-vehicle LAN communication means for transmitting and receiving messages connected to a plurality of in-vehicle LANs,
Message selecting means for selecting and receiving a message to be relayed via each in-vehicle LAN communication means;
A message storage means for temporarily storing the relay target messages sent from the message selection means to each in-vehicle LAN communication means by interposing between the message selection means and each in-vehicle LAN communication means;
A transmission management means for monitoring whether each in-vehicle LAN communication means is in a transmittable state and outputting the message stored in the message storage means to the in-vehicle LAN communication means when it is in a transmittable state; A relay connection unit is provided.

  According to the above configuration, a message received from each in-vehicle LAN is selected as a relay target by the message selection unit, and this relay target message is stored in the message storage unit in a queue corresponding to each LAN communication unit. . Since there is a message queue in each message storage means, the transmission management means monitors whether each in-vehicle LAN communication means is in a transmittable state, and when it is in a transmittable state, The stored message may be output to the in-vehicle LAN communication means. Here, when each in-vehicle LAN cannot transmit a message, the message stays in the message storage means until communication is possible, but it is not affected by other in-vehicle LAN states.

The second invention is
In-vehicle LAN communication means for transmitting and receiving messages connected to a plurality of in-vehicle LANs,
Message selecting means for selecting and receiving a message to be relayed via each in-vehicle LAN communication means;
A message storage means for temporarily storing a relay target message sent from the message selection means to the in-vehicle LAN communication means by being interposed between the message selection means and the in-vehicle LAN communication means;
Storage area management means for managing the message storage area in the message recording means;
Transmission management means is provided for monitoring whether each in-vehicle LAN communication means is in a transmittable state and outputting a relay target message to the in-vehicle LAN communication means by using a storage area management means when the transmission is possible. ,
This storage area management means
The message storage area in the message storage means is divided into a plurality of slot areas to manage empty slot areas, and
When receiving a relay target message from the message selection means, while recording at least the relay target message, information indicating the transmission destination, and position information of the next slot area in the empty slot area,
When the transmission management means requests output of the relay target message, each frame stored in the message storage means is sequentially traced from the head slot area to the slot area indicated by the position information of the next slot area. The relay connection unit is characterized in that a message to be output to the in-vehicle LAN communication means in a transmittable state is output to the in-vehicle LAN communication means communication means.

  Of the messages communicated in each in-vehicle LAN, the message to be relayed is selected by the message selection means and received via the in-vehicle LAN communication means. This relay target message is stored in the message storage means. At this time, the message selection means outputs the relay target message and information indicating the relay destination to the storage area management means of the message storage means, and the storage area management means at least in each slot area in the message storage means A frame composed of a message, information indicating the relay destination, and position information of the next slot area is recorded.

  That is, the storage area management means records a frame in which position information of the next slot area is included in each slot area, thereby dividing the common storage area in the message storage means into a plurality of slot areas and chaining them together. Manage to connect to the structure. In addition, since information indicating the relay destination is recorded in the slot area, the transmission management unit can determine the relay destination of the relay target message only by confirming the information of each slot area, and the corresponding in-vehicle LAN The relay target message can be transmitted to the communication means.

  When the relay of the message to all the in-vehicle LAN communication means specified in the information indicating the relay destination is completed, the frame is deleted, and the position information of the next slot area in the previous slot area is deleted. The portion may be changed to the position information of the next slot area instead of the position information of the slot area where the deleted frame was recorded. That is, even if the number of in-vehicle LAN communication means to be connected increases, complicated signal processing is not necessary, and a message can be relayed to the in-vehicle LAN side of each relay destination simply by performing predetermined simple signal processing. Therefore, the storage area management means and the transmission management means can be formed by simpler hardware, thereby further increasing the speed.

  As described above, according to the first invention, the transmission management means monitors whether or not each in-vehicle LAN communication means is in a transmittable state, and is provided correspondingly when it is in a transmittable state. Since the message stored in the message storage means may be output to the in-vehicle LAN communication means, the load of signal processing applied to the transmission management means can be reduced. In addition, the management of the message storage means is extremely simple and no advanced information processing is required. Therefore, all message reception processing, relay processing, and transmission processing can be realized with simple hardware, so high-speed processing is performed. Can do. Needless to say, since the signal processing is simple, high-speed processing can be performed using software.

  Further, since the message stored in the message storage means is not affected by the state of other in-vehicle LAN, even if a high load state occurs temporarily in a specific in-vehicle LAN, the message is lost. There is nothing.

  According to the second invention, since messages to be relayed to a plurality of in-vehicle LANs are recorded in the shared storage area in the message storage unit, a specific in-vehicle LAN is temporarily stored while keeping the capacity of the message storage unit small. Even if a heavy load occurs, it is possible to sufficiently prevent the message from being lost. In addition, since information indicating the relay destination is recorded in the frame stored in each slot area of the message storage means, the transmission management means only relays the message to be relayed by confirming the information of each frame. Confirm the destination and send the relay target message.

  By dividing the message storage means into a plurality of slot areas and including the position information of the next slot area in each frame, each slot area can be managed so as to be linked to each other in a chain structure. Therefore, when deleting a frame for which relay processing has been completed, a new chain structure can be easily formed simply by rewriting the position information of the next slot area in the frame recorded in the previous slot area. Since these processes can also be realized by relatively simple signal processing, the storage area management means can be easily formed by hardware, thereby reducing the delay time.

  FIG. 1 is a diagram showing a configuration of an in-vehicle LAN system A using a relay connection unit 1 according to an embodiment of the present invention. Reference numeral 2 denotes an ECU connected to each relay connection unit 1 (hereinafter, reference numerals 2A, 2B... Are used when distinguishing each ECU 2 from each other). Reference numeral 3 denotes a communication line that connects each ECU 2 to the relay connection unit 1. (Hereinafter, the symbols 3A, 3B,... Are used when the communication lines 3 are described separately).

  The ECUs 2 are provided with message input / output means 2a conforming to the CAN standard, for example, and the communication line 3 is a twisted pair cable conforming to the CAN standard. Each of the communication lines 3A, 3B,... May constitute an in-vehicle LAN that conforms to various standards such as LIN, CAN, FlexRay (registered trademark), MOST, D2B, IDB1394, Ethernet (registered trademark), and the like. Good. Moreover, the vehicle-mounted LAN based on a different standard for every communication line 3 may be comprised.

  Each communication line 3A, 3B, 3C, 3D is connected to a group of ECUs 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, respectively, and the segments sa, sb, sc, The relay connection unit 1 forms an in-vehicle LAN network 4 configured to be communicable with each other by relaying the plurality of in-vehicle LANs sa to sd. Needless to say, a single ECU 2 may be connected to each of the vehicle-mounted LANs sa to sd to perform more reliable communication.

  FIG. 2 is a diagram illustrating an internal configuration of the relay connection unit 1 according to the first embodiment. In FIG. 2, 10a to 10d are connected to the in-vehicle LANs sa to sd to transmit and receive messages, and 11 is a message to be relayed (relay target message) via each of the in-vehicle LAN communication units 10a to 10d. Message selection means (hereinafter referred to as a search engine) to be selected and received, 12 is a relay target identification information recording means (hereinafter referred to as a lookup table), and 13a to 13d are between the search engine 11 and each in-vehicle LAN communication means 10. An intervening message storage means 14 is a transmission management means. Note that the means 10a to 10d and 13a to 13d will be described using reference numerals 10 and 13 when distinction is not necessary in the following description.

  The in-vehicle LAN communication means 10 enables message input / output by performing communication conforming to CAN, and conforms to the CAN transceiver and the CAN standard for exchanging electrical signals to the communication line 3. And a CAN controller that controls communication according to the communication protocol. In this embodiment, an example including four in-vehicle LAN communication means 10a to 10d is shown for the sake of simplicity of explanation, but the present invention is limited to the number of in-vehicle LAN communication means 10 being four. Instead, it may be connected to any number of three or more in-vehicle LANs.

  The search engine 11 collates this identification information with the contents of the lookup table 12 when receiving the identification information (sender) of the message being received via each of the in-vehicle LAN communication means 10a to 10d. Messages that are relay targets that should be multicast to other in-vehicle LANs are received as relay target messages, and messages that are not relay targets are stopped from the in-vehicle LAN communication means 10a to 10d. As a result, the in-vehicle LAN communication means 10 can be prepared for transmission / reception of the next message without performing useless reception processing. However, the in-vehicle LAN communication means 10 outputs a message after reception completion to the search engine 11, and the search engine 11 determines whether it is necessary to receive the message received by the in-vehicle LAN communication means 10 as a relay target message. You may do it.

  Further, when the reception of the relay target message is completed, the search engine 11 determines, based on the transmission destination information indicated by the lookup table 12, at least message storage means 13 (message storage means 13a, 13b... 1) The relay target message is output. The output of the relay target message may be pipeline processed via the search engine 11 during the reception of messages sequentially received by the in-vehicle LAN communication means.

  As shown in FIG. 3, the lookup table 12 includes identification information Id of a message to be relayed and information (channel information) Ch indicating a relay destination. Although various modifications can be considered in the setting method of the relay destination channel information Ch, for example, bit information indicating the necessity of transmission to the channels a to d arranged according to each of the in-vehicle LAN communication units 10 a to 10 d. Can be considered.

  The message storage unit 13 is, for example, a FIFO type memory that temporarily stores relay target messages sent from the search engine 11 to the in-vehicle LAN communication units 10a to 10d as corresponding queues. In this embodiment, in order to simplify the description, an example in which a FIFO type memory for creating a single queue is provided for each of the in-vehicle LAN communication units 10a to 10d is shown. Queues for messages and transmission cycles may be created separately (that is, two FIFO memories may be provided for each of the in-vehicle LAN communication units 10a to 10d). Furthermore, a separate memory may be provided for a relay target message that defines a transmission cycle.

  The communication management means 14 monitors the states A1 to A4 of the in-vehicle LAN communication means 10a to 10d, and outputs signals S1 to S4 to the corresponding message storage means 13a, 13b. The relay target messages stored in these are output to the in-vehicle LAN communication means 10a, 10b,.

  By using the relay connection unit 1 of the first embodiment configured as described above, relays to be relayed among the messages received from the in-vehicle LAN sa, sb... Via the in-vehicle LAN communication means 10a, 10b. The search message is selectively received by the search engine 11 and output to the message storage means 13a, 13b,... Connected to the in-vehicle LAN communication means 10a, 10b,. This can be temporarily stored.

  And when each vehicle-mounted LAN communication means 10a-10d can transmit, the relay object message memorize | stored in each message memory | storage means 13a, 13b ... can be transmitted to vehicle-vehicle LANsa, sb ... each required. That is, the relay target message necessary in the in-vehicle LAN network 4 can be multicast. Note that since the relay target message is not transmitted to the in-vehicle LANs that do not need to be relayed, the load is not increased. Further, even if a situation occurs in which the load is temporarily increased in each in-vehicle LANsa, sb... And transmission is impossible, the message storage means 13 is formed for each in-vehicle LANsa, sb. Even if the LANs are temporarily heavily loaded, there is no loss of messages.

  Furthermore, since the configuration of each of the units 10 to 14 is very simple, all the units can be easily formed by hardware. Therefore, the time required for relaying the relay target message can be minimized, and the delay time can be reduced accordingly.

  FIG. 4 is a diagram illustrating an internal configuration of the relay connection unit 20 according to the second embodiment. In FIG. 4, since the part which attached | subjected the same code | symbol as FIG. 2 is the same or equivalent member, the detailed description is abbreviate | omitted. 21 is a message selection means (hereinafter referred to as a search engine) for selecting and receiving a relay target message via each of the in-vehicle LAN communication means 10a to 10d, 22 is a relay target identification information recording means (hereinafter referred to as a lookup table), 23 is a message storage means interposed between the surge engine 21 and the in-vehicle LAN communication means 10a to 10d, and 24 is a storage area management means for managing the message storage area 23a in the message recording means 23 as one integrated slot area ( (Hereinafter referred to as a slot manager) 25 is used to monitor whether or not each of the in-vehicle LAN communication means 10a to 10d is in a transmittable state, and when it is in a transmittable state, the slot manager 24 is used to send a relay target message It is a transmission management means to make the communication means 10a-10d output.

  Similar to the search engine 11 shown in FIG. 2, the search engine 21 compares the identification information (source) of the message received via each in-vehicle LAN communication means 10 a to 10 d with the contents of the lookup table 12. The in-vehicle LANs also receive a relay target message to be multicast, but add information indicating the relay destination (the channel information Ch) to the received relay target message and output it to the storage area management means 23. is there.

  Further, as shown in FIG. 5, information (channel information) Ch indicating a transmission destination and a message discard timer T are recorded in the lookup table 22 in association with the identification information Id of the transmission source. The channel information Ch shown in this example is, for example, 2 bits of bit information arranged in accordance with the relay destination channel. The relay target is not transmitted (00), is normally transmitted (10), and is transmitted preferentially ( 11) It is conceivable to set (01) to transmit periodically according to a periodic timer (described later). That is, the channel information Ch includes not only information indicating the transmission destination but also information indicating the priority order of the message.

  As shown in FIG. 6, the slot manager 24 can execute a simple control program for dividing the message storage area 23a in the message storage means 23 into a plurality of slot areas SL1, SL2,. An arithmetic processing unit. SL0 is a slot area management area in which position information Ts of the first transmission slot area, position information Ls of the last transmission slot area, position information Fs of unused transmission slot areas, and the like are recorded. In each slot area SL1, SL2,..., The relay target message Msg, the channel information Ch, the message discard timer value T, the position information Bs of the previous slot area, and the position information of the next slot area. A frame consisting of Ns is recorded.

  In the state shown in FIG. 6, a frame including the relay target message Msg is stored in the slot areas SL9, SLA, SL2... SLx, and the slot areas SL1, SL3, SL4.

  The transmission management unit 25 monitors the states A1 to A4 of the in-vehicle LAN communication units 10a to 10d, and outputs a signal Sch indicating a channel that can be transmitted to the slot management 24 when it is in a transmittable state. Then, the relay target message is output to the in-vehicle LAN communication means 10a to 10d by using.

  The transmission management unit 25 monitors whether or not each of the in-vehicle LAN communication units 10a to 10d is in a transmittable state, and when it is in a transmittable state, uses the slot management 24 to send a relay target message to the in-vehicle LAN communication unit 10a. -10d.

  Next, the operation in the relay connection unit 20 of this embodiment will be described. First, when a message is received from each of the vehicle-mounted LANs sa to sd via the vehicle-mounted LAN communication means 10a to 10d, the search engine 21 uses the identification information of this message to determine whether or not this is a relay target and is a relay target. Then, the channel information Ch and the discard timer T are added to the relay target message Msg, and the information Msg, Ch, T is output to the slot manager 24.

  When the slot manager 24 receives these pieces of information Msg, Ch, and T, at least the relay target message Msg is stored in the empty slot area SL1 (the example in the state shown in FIG. 6) indicated by the position information Fs of the empty slot area. Then, a frame composed of the information Ch, T, Bs, and Ns is recorded, and the content of the position information Fs of the empty slot area is rewritten to “3” to indicate the next empty slot area SL3. Further, the position information Ns of the next slot area of the frame at the position indicated by the position information Ls of the last transmission slot area and the contents of the position information Ls of the last transmission slot area are rewritten to “1”.

  In this example, the position information Bs of the previous slot area included in the frame to be newly recorded in the empty slot area SL1 is “x”, and the position information Ns of the next slot area is “0”. That is, this “0” indicates the end of each slot region connected in a chain state.

  On the other hand, when a signal Sch of a channel that can be transmitted is input from the transmission management means 25 to the slot management 24, the slot manager 24 gives priority to the one corresponding to the priority transmission (bit information “11”) alternately. The mode to be selected and output, and the mode to output in the order recorded in the slot area SL1. In any case, the slot manager 24 first reads the frame of the slot region SL9 (in the case of the example shown in FIG. 6), which is the head indicated by the position information Ts of the head transmission slot region, and can now transmit it to the channel information Ch. When a correct channel is included, the message Msg included in this frame is output to the in-vehicle LAN communication means 10, and the bit information corresponding to the transmitted channel is deleted from the channel information Ch of this frame.

  If the channel information Ch of the frame read here is different from the channel that can be transmitted now, the position information Ns of the next slot area is traced to the next slot area SLA, SL2... In the message storage area 23a. Read the recorded frames sequentially. If the position information Ns of the next slot area is “0”, there is no relay target message to be transmitted to a channel that can be transmitted in the frame in the message storage area 23a, so nothing is performed.

  On the other hand, when the slot manager 24 finishes outputting the message Msg read from the message storage area 23a to the in-vehicle LAN communication means 10, it is confirmed whether the channel information Ch of the frame still leaves the relay destination. If no relay destination remains, this frame is deleted, its position information is registered in the position information Fs of the empty slot area, and connected to a chain indicating the empty slot area. In addition, it is necessary to repair the chain state connection before and after the slot area in which the deleted frame was recorded.

  FIG. 7 is a diagram illustrating a procedure for restoring the previous and subsequent connections when one slot area is deleted. As shown in FIG. 7A, when deleting a frame recorded in the slot area SLA when the slot areas SL9, SLA, and SL2 are sequentially connected in a chain state, one frame before the deletion is considered. The position information Ns of the next slot area recorded in the slot area SLA is transferred to the position information Ns of the next slot area of the frame recorded in the slot area SL9. Similarly, the contents of the position information Bs of the previous slot area recorded in the slot area SLA are transferred to the position information Bs of the slot area before the frame recorded in the immediately preceding slot area SL2.

  As shown in FIG. 7B, it is possible to restore a new chain state connection in which the deleted slot area SLA is skipped, by transferring only two pieces of information Bs and Ns as described above. That is, each message Msg recorded in the slot area SL1 connected in the chain state can be taken out from an arbitrary position and output to the in-vehicle LAN communication means 10, and the vacant area can be utilized in a relatively simple manner.

  Therefore, in the relay connection unit that relays a plurality of in-vehicle LANs sa, sb..., The slot area in the message storage unit can be unified, so that the message storage area with a smaller capacity can be used effectively. Even if the load becomes high, it is possible to more reliably prevent the message from being lost.

  In addition, although the slot area in the message storage means is managed without waste, the management is relatively easy, so it is possible to form all the means 10, 21 to 25 by hardware. Yes, speeding up can be achieved. Even if software processing is partially used, since there is no complicated signal processing, processing can be performed at a higher speed and reliability can be improved.

  In the above example, the information of the discard timer T is attached to the message Msg, so that the slot manager 24 can detect a frame that has remained for a long time that cannot be transmitted after the time determined by the discard timer T. It is also possible to delete it.

It is a figure which shows the structure of the communication LAN network formed using the relay connection unit of this invention. It is a figure which shows 1st Example of a relay connection unit. It is a figure which shows the example of the relay object identification information recording information used for the said relay connection unit. It is a figure which shows 2nd Example of a relay connection unit. It is a figure which shows the example of the relay object identification information recording information used for the said relay connection unit. It is a figure which shows the example of the message storage means of the said relay connection unit. It is a figure which shows the example of the signal processing in the said message storage means. It is a figure which shows the structure of the relay connection unit using the conventional general CAN communication means. It is a figure which shows the structure of another conventional relay connection unit.

Explanation of symbols

1 Relay connection unit 2 ECU
3 Communication line 4 In-vehicle LAN network 10 In-vehicle LAN communication means 11, 21 Message selection means 14, 25 Transmission management means 13, 23 Message storage means 24 Storage area management means SL1, SL2... Slot area Msg Relay target message Ch Indicates a transmission destination Information Ns Position information of the next slot area

Claims (2)

In-vehicle LAN communication means for transmitting and receiving messages connected to a plurality of in-vehicle LANs,
Message selecting means for selecting and receiving a message to be relayed via each in-vehicle LAN communication means;
A message storage means for temporarily storing the relay target messages sent from the message selection means to each in-vehicle LAN communication means by interposing between the message selection means and each in-vehicle LAN communication means;
A transmission management means for monitoring whether each in-vehicle LAN communication means is in a transmittable state and outputting the message stored in the message storage means to the in-vehicle LAN communication means when it is in a transmittable state; A relay connection unit characterized by In-vehicle LAN communication means for transmitting and receiving messages connected to a plurality of in-vehicle LANs,
Message selecting means for selecting and receiving a message to be relayed via each in-vehicle LAN communication means;
A message storage means for temporarily storing a relay target message sent from the message selection means to the in-vehicle LAN communication means by being interposed between the message selection means and the in-vehicle LAN communication means;
Storage area management means for managing the message storage area in the message recording means;
Transmission management means is provided for monitoring whether each in-vehicle LAN communication means is in a transmittable state and outputting a relay target message to the in-vehicle LAN communication means by using a storage area management means when the transmission is possible. ,
This storage area management means
The message storage area in the message storage means is divided into a plurality of slot areas to manage empty slot areas, and
When receiving a relay target message from the message selection means, while recording at least the relay target message, information indicating the transmission destination, and position information of the next slot area in the empty slot area,
When the transmission management means requests output of the relay target message, each frame stored in the message storage means is sequentially traced from the head slot area to the slot area indicated by the position information of the next slot area. A relay connection unit characterized in that a message to be output to the in-vehicle LAN communication means in a transmittable state is output to the in-vehicle LAN communication means communication means.

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