Program, frame conversion device, and method

Abstract

To provide a program, a frame conversion device, and a method that can handle even in a case in which frames whose addresses are different are mixed, and reduce the usage band of a network.SOLUTION: A frame conversion device 10 that is arranged between a first network 20 and a second network 30 whose protocols are different distributes the frames of the first networks 20 to buffers 12-1, 12-2 corresponding to the addresses in the second network 30 depending on the addresses, and outputs the frame of the second network 30 in which one header including the address is added to the set number of frames output from the associated buffers 12-1, 12-2.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a program, a frame conversion device, and a method.

Background Art

[0002] Patent Document 1 discloses a control unit disposed between a first network based on a first protocol and a second network based on a second protocol. The first network and the second network are, for example, CAN (Controller Area Network) and Ethernet (registered trademark). This control unit forms a frame based on a second protocol from a frame based on a first protocol from the first network and outputs this to the second network.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is a demand regarding reduction of the transmission bandwidth of a network.

[0005] The inventor has found that in Patent Document 1, there may not have been sufficient consideration regarding reduction of the transmission bandwidth of the network. Also, the inventor has found that in Patent Document 1, there may not have been sufficient consideration regarding what processing is to be performed when there are a plurality of destinations.

[0006] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

Means for Solving the Problems

[0007] According to one embodiment, a frame conversion device, which is installed between first and second networks with different protocols, distributes frames from the first network to buffers corresponding to destinations in the second network, and outputs frames from the second network by adding a single header containing the destination to a set number of frames output from the buffers. [Effects of the Invention]

[0008] According to the above embodiment, it is possible to handle cases where frames with different destinations are mixed together, and the network bandwidth usage can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an example of the system in the first embodiment. [Figure 2] Figure 2 is a block diagram showing an example of a frame conversion device in the first embodiment. [Figure 3] Figure 3 shows a specific example of the system configuration in the first embodiment. [Figure 4] Figure 4 is a timing chart for frame transmission in the system of the first embodiment. [Figure 5] Figure 5 is a block diagram showing an example of a frame conversion device in the second embodiment. [Figure 6] Figure 6 is a block diagram showing an example of a frame conversion device in Modification 1 of the second embodiment. [Figure 7] Figure 7 is a block diagram showing an example of a frame conversion device in the third embodiment. [Figure 8] Figure 8 is a block diagram showing an example of a frame conversion device in a modified example 4 of the third embodiment. [Figure 9] Figure 9 is a block diagram showing an example of a frame conversion device in a modified example 6 of the third embodiment. [Figure 10] Figure 10 is a block diagram showing an example of a frame conversion device in the fourth embodiment. [Figure 11] Figure 11 shows an example of the hardware configuration of a frame conversion device. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. In these embodiments, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] <First Embodiment> <System Overview> Figure 1 shows an example of a system in the first embodiment. In Figure 1, system 1 includes a frame conversion device 10, a first network 20, and a second network 30.

[0012] The first network 20 is a network based on the first protocol. The second network 30 is a second network based on the second protocol. The first protocol and the second protocol are different protocols. Therefore, the format of frames transmitted in the first network 20 is different from the format of frames transmitted in the second network 30. For example, but not limited to this, one of the first network 20 and the second network 30 may be CAN and the other may be Ethernet.

[0013] The frame converter 10 is installed between the first network 20 and the second network 30. For example, the frame converter 10 receives a frame based on the first protocol from the first network 20 and converts this frame based on the first protocol into a frame based on the second protocol. The frame converter 10 then outputs the frame based on the second protocol to the second network 30.

[0014] <Example of Frame Conversion Device Configuration> FIG. 2 is a block diagram showing an example of a frame conversion device according to the first embodiment. In FIG. 2, the frame conversion device 10 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, and a storage unit 14. The buffer 12-1 and the buffer 12-2 are respectively associated with a first destination and a second destination in the "destination buffer mapping information (that is, the correspondence relationship)". The "destination buffer mapping information" may be, for example, a destination buffer mapping table. This destination buffer mapping table is stored in the storage unit 14. Also, for example, the first destination may be a first processing unit (not shown) arranged in the second network 30, and the second destination may be a second processing unit (not shown) arranged in the second network 30. Hereinafter, when the buffer 12-1 and the buffer 12-2 are not distinguished, they may be collectively referred to as the buffer 12. Here, for the sake of simplicity of explanation, the number of buffers 12 included in the frame conversion device 10 is set to two, but it is not limited thereto. That is, the number of buffers 12 included in the frame conversion device 10 may be three or more. Even in this case, the three or more buffers 12 are respectively associated with different destinations.

[0015] The distribution unit 11 receives a frame based on the first protocol from the first network 20. The frame based on the first protocol includes "destination information" in the header part of the frame. Here, the "destination information" indicates the above-mentioned first destination or second destination.

[0016] The distribution unit 11 distributes a frame based on the first protocol to a buffer 12 associated with the destination indicated by the destination information of this frame by destination buffer mapping information. For example, when the destination information of a frame based on the first protocol indicates a first destination, the distribution unit 11 distributes this frame based on the first protocol to the buffer 12-1 associated with the first destination. Note that the distribution unit 11 may output the frame based on the first protocol (that is, both the header part and the payload part) to the buffer 12 as it is, or may output the payload part obtained by removing the header part of the frame based on the first protocol to the buffer 12.

[0017] The buffer 12-1 holds the frame distributed from the distribution unit 11 (that is, the frame whose destination is the first destination). Then, when the number of frames held by the buffer 12-1 reaches M, the buffer 12-1 outputs M frames collectively to the conversion unit 13.

[0018] The buffer 12-2 holds the frame distributed from the distribution unit 11 (that is, the frame whose destination is the second destination). Then, when the number of frames held by the buffer 12-2 reaches N, the buffer 12-2 outputs N frames collectively to the conversion unit 13.

[0019] Here, the values of M and N are each an integer of 1 or more. Also, at least one of the values of M and N is an integer of 2 or more. And the value of M may be the same as or different from the value of N. The values of M and N may each be referred to as the "buffer size".

[0020] The conversion unit 13 forms a frame based on the second protocol by adding a header based on the second protocol to the entirety of the M frames output from buffer 12-1. That is, the conversion unit 13 includes the entirety of the M frames output from buffer 12-1 as the payload portion of the frame based on the second protocol. Furthermore, the conversion unit 13 forms a frame based on the second protocol by adding a header based on the second protocol that includes the first destination to the payload portion of the frame based on the second protocol.

[0021] Similarly, the conversion unit 13 forms a frame based on the second protocol by adding a header based on the second protocol to the entirety of the N frames output from buffer 12-2. That is, the conversion unit 13 includes the entirety of the N frames output from buffer 12-2 as the payload portion of the frame based on the second protocol. Furthermore, the conversion unit 13 forms a frame based on the second protocol by adding a header based on the second protocol that includes the second destination to the payload portion of the frame based on the second protocol.

[0022] As described above, even when the payload portion of a frame based on the first protocol is held in buffer 12 after the header portion has been removed, the conversion unit 13 can identify the destination to which buffer 12, the source of the frame output, is associated by referring to the destination buffer mapping information. For this reason, the conversion unit 13 can include the "first destination" in the header portion of a frame based on the second protocol formed from M frames output from buffer 12-1. On the other hand, the conversion unit 13 can include the "second destination" in the header portion of a frame based on the second protocol formed from N frames output from buffer 12-2.

[0023] The conversion unit 13 then outputs a frame based on the formed second protocol to the second network 30. This frame based on the second protocol is received, for example, by a processing unit indicated by the destination information contained in its header.

[0024] <Example of system operation> An example of the processing operation of System 1 having the above configuration will now be described. Figure 3 is a diagram showing a specific configuration example of the system in the first embodiment. Figure 4 is a timing chart related to frame transmission in the system of the first embodiment. Here, an example of the processing operation will be described based on the specific configuration example of the system shown in Figure 3. Note that the storage unit 14 of the frame converter 10 is not shown in Figure 3.

[0025] In Figure 3, the first network 20 includes processing modules 21-1, 21-2, and 21-3. The second network 30 also includes processing units 31-1, 31-2, and 31-3.

[0026] Processing module 21-1 outputs frame F11 based on the first protocol, addressed to processing unit 31-1. Processing module 21-2 outputs frame F12 based on the first protocol, addressed to processing unit 31-2. Processing module 21-3 outputs frame F13 based on the first protocol, addressed to processing unit 31-3.

[0027] More specifically, as shown in Figure 4, processing module 21-1 outputs frames F11-1, F11-2, and F11-3. Processing module 21-2 outputs frames F12-1, F12-2, and F12-3. Processing module 21-3 outputs frames F13-1, F13-2, and F13-3.

[0028] Furthermore, as shown in Figure 3, the frame conversion device 10 includes a distribution unit 11, buffers 12-1, 12-2, and 12-3, and a conversion unit 13. Buffers 12-1, 12-2, and 12-3 are associated with destinations 1, 2, and 3, respectively, in the "destination buffer mapping information". Destinations 1, 2, and 3 are associated with processing units 31-1, 31-2, and 31-3, respectively.

[0029] The distribution unit 11 distributes frames F11-1, F11-2, and F11-3 to buffer 12-1 corresponding to destination 1 (i.e., processing unit 31-1). The distribution unit 11 also distributes frames F12-1, F12-2, and F12-3 to buffer 12-2 corresponding to destination 2 (i.e., processing unit 31-2). Furthermore, the distribution unit 11 distributes frames F13-1, F13-2, and F13-3 to buffer 12-3 corresponding to destination 3 (i.e., processing unit 31-3). In this way, the distribution unit 11 distributes frames from the first network 20 to the buffer 12 corresponding to the destination in the second network 30 according to the destination. This makes it possible to realize a frame conversion device 10 that can handle cases where frames with different destinations are mixed together.

[0030] Here, the "buffer size" of each buffer 12-1, 12-2, and 12-3 is assumed to be the size of three frames based on the first protocol. That is, each buffer 12-1, 12-2, and 12-3 holds three frames based on the first protocol and outputs them together to the conversion unit 13.

[0031] The conversion unit 13 then forms a frame F21 based on the second protocol, which includes a header portion H21 and a payload portion P21. The payload portion P21 of this frame F21 based on the second protocol includes frames F11-1, F11-2, and F11-3 that are output together from buffer 12-1. The header portion H21 of this frame based on the second protocol includes destination information indicating processing unit 31-1. The conversion unit 13 then outputs the formed frame F21 based on the second protocol to the second network 30.

[0032] Furthermore, the conversion unit 13 forms a frame F22 based on the second protocol, which includes a header portion H22 and a payload portion P22. The payload portion P22 of this frame F22 based on the second protocol includes frames F12-1, F12-2, and F12-3 that are output together from buffer 12-2. The header portion H22 of this frame based on the second protocol includes destination information indicating processing unit 31-2. The conversion unit 13 then outputs the formed frame F22 based on the second protocol to the second network 30.

[0033] Furthermore, the conversion unit 13 forms a frame F23 based on the second protocol, which includes a header portion H23 and a payload portion P23. The payload portion P23 of this frame F23 based on the second protocol includes frames F13-1, F13-2, and F13-3 that are output together from buffer 12-3. The header portion H23 of this frame based on the second protocol includes destination information indicating processing unit 31-3. The conversion unit 13 then outputs the formed frame F23 based on the second protocol to the second network 30.

[0034] In this way, the conversion unit 13 forms a frame for the second network 30 by adding a single header containing the destination to the set number of frames output collectively from the buffer 12, and outputs this frame to the second network 30. This reduces the overhead caused by the header of the frame based on the second protocol compared to the case where a header based on the second protocol is added to each frame based on the first protocol to form a frame based on the second protocol. As a result, the bandwidth used by the second network 30 can be reduced.

[0035] <Second Embodiment> The second embodiment relates to adjusting destination buffer mapping information that shows the correspondence between a buffer and a destination, or adjusting the buffer size, etc.

[0036] Figure 5 is a block diagram showing an example of a frame conversion device in the second embodiment. In Figure 5, the frame conversion device 40 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, a storage unit 14, and an adjustment unit 41. The basic configuration of the system in the second embodiment is the same as system 1 shown in Figure 1. That is, system 1 in the second embodiment has a frame conversion device 40 instead of a frame conversion device 10. Here, for the sake of simplicity, the number of buffers 12 in the frame conversion device 40 is assumed to be two, but it is not limited to this. That is, the number of buffers 12 in the frame conversion device 40 may be three or more. Even in this case, the three or more buffers 12 are each associated with a different destination.

[0037] In the second embodiment, the value of M, which is the buffer size of buffer 12-1, is different from the value of N, which is the buffer size of buffer 12-2. In the following, the value of M is smaller than the value of N.

[0038] The adjustment unit 41 adjusts destination buffer mapping information that shows the correspondence between buffers 12-1, 12-2 and the first and second destinations. The destination buffer mapping information is stored in the storage unit 14. The adjustment unit 41 adjusts the destination buffer mapping information based on the "priority" of the first and second destinations. For example, the adjustment unit 41 adjusts the destination buffer mapping information by referring to "priority information" and "buffer information". The "priority information" associates destinations with the priority corresponding to those destinations. In other words, the "priority information" associates processing units with the priority corresponding to those processing units. For example, the more urgently a processing unit is required to process, the higher the priority associated with that processing unit. The "priority information" is, for example, a "priority table". The "priority table" is stored in the storage unit 14. The "buffer information" associates relative priorities with buffers corresponding to those relative priorities. For example, the "buffer information" may associate buffer 12-1 with a relative priority of "high" and buffer 12-2 with a relative priority of "low". The "buffer information" is, for example, a "buffer table". The "buffer table" is stored in the storage unit 14.

[0039] For example, if the priority of a destination changes depending on the timing (e.g., time of day), the priority information may include first priority information for the first timing and second priority information for the second timing. For example, the first priority information for the first time period specifies that the priority of the first destination is higher than that of the second destination. On the other hand, the second priority information for the second time period specifies that the priority of the first destination is lower than that of the second destination. The adjustment unit 41 then refers to the first priority information and buffer information in the first time period (i.e., the first timing) and adjusts the destination buffer mapping information so that the first destination with higher priority is associated with buffer 12-1 and the second destination with lower priority is associated with buffer 12-2. This makes it possible to prioritize reducing the delay until the frame reaches the destination (processing unit) rather than reducing the bandwidth used by the second network 30 for destinations (processing units) with relatively high priority. Furthermore, during the second time zone (i.e., the second timing after the first timing), the adjustment unit 41 refers to the second priority information and buffer information and adjusts the destination buffer mapping information so that the second destination with higher priority is associated with buffer 12-1 and the first destination with lower priority is associated with buffer 12-2.

[0040] The distribution unit 11 distributes the frame based on the first protocol to the buffer 12 that is associated with the destination indicated by the destination information of the frame in the adjusted destination buffer mapping information. The conversion unit 13 also identifies the destination to which the buffer 12 that is the source of the frame is associated by referring to the adjusted destination buffer mapping information when the payload portion of the frame based on the first protocol has been removed and is held in the buffer 12.

[0041] By adjusting the destination buffer mapping information in this way, the adjustment unit 41 can hold frames for high-priority destinations in the buffer 12-1 with a smaller buffer size, thereby reducing the delay caused by buffering of frames for high-priority destinations. This allows frames for high-priority destinations to be delivered to their destinations more quickly.

[0042] Furthermore, the adjustment unit 41 adjusts the destination buffer mapping information when no frames are accumulated in buffers 12-1 and 12-2. This prevents frames with different destinations from being accumulated in a single buffer.

[0043] <Modified form of the second embodiment> The frame conversion device 40 of the second embodiment may be modified as follows.

[0044] <Modified Example 1> Figure 6 is a block diagram showing an example of a frame conversion device in modified example 1 of the second embodiment. In Figure 6, the frame conversion device 40 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, a storage unit 14, and an adjustment unit 42.

[0045] In Modification 1 of the Second Embodiment, the destination buffer mapping information associates the first destination with buffer 12-1 and the second destination with buffer 12-2. In other words, the Modification of the Second Embodiment assumes that the destination buffer mapping information is fixed.

[0046] The adjustment unit 42 adjusts the value of M (i.e., the buffer size of buffer 12-1) based on the priority of the first destination. The adjustment unit 42 also adjusts the value of N (i.e., the buffer size of buffer 12-2) based on the priority of the second destination. The adjustment of the value of M based on the priority of the first destination and the adjustment of the value of N based on the priority of the second destination may be performed independently. In other words, the adjustment of the values ​​of M and N may be performed based on the absolute priority of the first and second destinations.

[0047] For example, the adjustment unit 42 adjusts the buffer size of buffer 12 by referring to "priority information," "buffer size information," and "destination buffer mapping information." The "priority information" and "destination buffer mapping information" are the same as those in the second embodiment. The "buffer size information" associates the priority type of a processing unit that can be associated with a processing unit with the buffer size corresponding to that priority type. For example, suppose there are three priority levels: high, medium, and low. In this case, the "buffer size information" associates buffer sizes 1, 2, and 3 with high, medium, and low priorities, respectively. The adjustment unit 42 may adjust the value of M according to this "buffer size information" and the priority of the first destination (first processing unit), and may also adjust the value of N according to this "buffer size information" and the priority of the second destination (second processing unit). The "buffer size information" is, for example, a "buffer size table." The "buffer size table" is stored in the storage unit 14.

[0048] For example, suppose the first priority information for the first time period associates a high priority with the first processing unit (first destination) and a low priority with the second processing unit (second destination). In this case, the adjustment unit 42 refers to the first priority information and the buffer size information to identify a buffer size of "1" for the first processing unit (first destination). Then, the adjustment unit 42 refers to the "destination buffer mapping information" to identify the buffer 12-1 associated with the first processing unit (first destination) and adjusts the buffer size of this buffer 12-1 to "1".

[0049] This adjustment by the adjustment unit 42 allows the buffer size of the buffer corresponding to a destination to be adjusted to be smaller the higher the priority of the destination. This makes it possible to deliver frames to high-priority destinations faster.

[0050] Furthermore, the adjustment unit 42 may adjust the buffer size of buffer 12 at a time when no frames have been accumulated in buffer 12. This reliably avoids the loss of accumulated frames that could occur if the buffer size value were adjusted while frames were being accumulated in buffer 12.

[0051] <Modification 2> The basic configuration of the frame conversion device in Modification 2 of the second embodiment is the same as that of the frame conversion device in Modification 1 of the second embodiment, so please refer to Figure 6.

[0052] In the modified version 2 of the second embodiment, the destination buffer mapping information associates the first destination with buffer 12-1 and the second destination with buffer 12-2. In other words, the modified version of the second embodiment assumes that the destination buffer mapping information is fixed.

[0053] In the modified example 2 of the second embodiment, the adjustment unit 42 adjusts the value of M (i.e., the buffer size of buffer 12-1) and the value of N (i.e., the buffer size of buffer 12-2) based on the priority of the first destination and the priority of the second destination. That is, the adjustment of the values ​​of M and N may be performed based on the relative priority of the first destination and the second destination.

[0054] For example, the adjustment unit 42 adjusts the buffer size of buffer 12 by referring to "priority information," "buffer size information," and "destination buffer mapping information." The "priority information" and "destination buffer mapping information" are the same as those in the second embodiment. The "buffer size information" associates relative priority with buffer size corresponding to that relative priority. For example, the "buffer size information" associates a buffer size value of "1" with a relative priority of "high" and a buffer size value of "3" with a relative priority of "low." The adjustment unit 42 refers to this "buffer size information" and adjusts the buffer size of buffer 12 corresponding to the higher priority of the first destination and the second destination to 1. The adjustment unit 42 also adjusts the buffer size of buffer 12 corresponding to the lower priority of the first destination and the second destination to 3. The "buffer size information" is, for example, a "buffer size table." The "buffer size table" is stored in the storage unit 14.

[0055] For example, suppose the first priority information for the first time period associates a high priority with the first processing unit (first destination) and a low priority with the second processing unit (second destination). In this case, the adjustment unit 42 refers to the first priority information and the buffer size information to identify a buffer size of "1" for the first processing unit (first destination). Then, the adjustment unit 42 refers to the "destination buffer mapping information" to identify the buffer 12-1 associated with the first processing unit (first destination) and adjusts the buffer size of this buffer 12-1 to "1".

[0056] Through this adjustment by the adjustment unit 43, if the priority of the first destination is higher than the priority of the second destination, the buffer size of buffer 12-1, which holds the frames of the higher-priority first destination, can be made smaller than that of buffer 12-2. This allows the frames of the higher-priority first destination to be delivered to the destination earlier than the frames of the second destination.

[0057] <Third Embodiment> The third embodiment relates to an embodiment that adjusts the buffer size of the buffer associated with each destination based on the transmission amount of each destination in the frame.

[0058] Figure 7 is a block diagram showing an example of a frame conversion device in the third embodiment. In Figure 7, the frame conversion device 50 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, a storage unit 14, a measurement unit 51, and an adjustment unit 52. The basic configuration of the system in the third embodiment is the same as system 1 shown in Figure 1. That is, system 1 in the third embodiment has a frame conversion device 50 instead of a frame conversion device 10. Here, for the sake of simplicity, the number of buffers 12 in the frame conversion device 50 is assumed to be two, but it is not limited to this. That is, the number of buffers 12 in the frame conversion device 50 may be three or more. Even in this case, the three or more buffers 12 are each associated with a different destination.

[0059] In the third embodiment, the destination buffer mapping information associates the first destination with buffer 12-1 and the second destination with buffer 12-2. In other words, the modified version of the third embodiment assumes that the destination buffer mapping information is fixed.

[0060] The measurement unit 51 measures the transmission amount for frames to the first destination based on the second protocol in the second network 30, and the transmission amount for frames to the second destination based on the second protocol in the second network 30. Hereinafter, the transmission amount for frames to the first destination based on the second protocol in the second network 30 may be simply referred to as the "first transmission amount." Similarly, hereafter, the transmission amount for frames to the second destination based on the second protocol in the second network 30 may be simply referred to as the "second transmission amount." The first transmission amount corresponds to the bandwidth of the second network 30 used by the frames to the first destination, and the second transmission amount corresponds to the bandwidth of the second network 30 used by the frames to the second destination.

[0061] The adjustment unit 52 adjusts the value of M (i.e., the buffer size of buffer 12-1) based on the first transmission amount measured by the measurement unit 51. For example, the adjustment unit 52 may adjust the value of M based on the first transmission amount measured by the measurement unit 51 and the "buffer size information". The "buffer size information" associates a buffer size with each of several ranges corresponding to the magnitude of the transmission amount. Specifically, the adjustment unit 52 may identify the buffer size in the "buffer size information" that corresponds to the range corresponding to the first transmission amount measured by the measurement unit 51, and adjust the value of M to this buffer size. The "buffer size information" may, for example, associate different buffer sizes (3, 2, 1) with each of three ranges corresponding to the magnitude of the transmission amount (large, medium, small). The "buffer size information" is, for example, a "buffer size table". The "buffer size table" is stored in the storage unit 14.

[0062] Similarly, the adjustment unit 52 adjusts the value of N (i.e., the buffer size of buffer 12-2) based on the second transmission amount measured by the measurement unit 51. For example, the adjustment unit 52 may adjust the value of N based on the second transmission amount measured by the measurement unit 51 and "buffer size information".

[0063] This adjustment by the adjustment unit 52 increases the buffer size of the buffer 12 associated with destinations with high transmission volumes, thereby increasing the number of frames output from the buffer 12 in batches. As a result, the conversion unit 13 adds a single header portion based on the second protocol to many of the frames output from the buffer 12, reducing the overhead of the header based on the second protocol. This reduces the amount of data transmitted to that destination in the second network 30, and thus reduces the bandwidth used by the second network 30.

[0064] Furthermore, if the first transmission amount measured by the measurement unit 51 exceeds the first threshold, the adjustment unit 52 may adjust the value of M (i.e., the buffer size of buffer 12-1) by raising the value of M from its current value to a predetermined value (for example, 1). The same applies to the value of N. In this way, the buffer size of buffer 12 associated with a destination where the transmission amount has increased more than expected can be increased, thereby increasing the number of frames output from buffer 12 in batches. As a result, one header portion based on the second protocol is added to many of the frames output from buffer 12 by the conversion unit 13, thus reducing the overhead of the header based on the second protocol. This reduces the transmission amount to that destination in the second network 30, and therefore reduces the bandwidth used by the second network 30.

[0065] Furthermore, if the first transmission amount measured by the measurement unit 51 falls below the second threshold, the adjustment unit 52 may adjust the value of M (i.e., the buffer size of buffer 12-1) by lowering it from its current value by a predetermined value (for example, 1). The same applies to the value of N. This makes it possible to reduce the buffer size of buffer 12 associated with destinations where the transmission amount has fallen below expectations. This makes it possible to deliver frames to destinations where the transmission amount has fallen below expectations more quickly.

[0066] Here, the adjustment unit 52 adjusts the buffer size of buffer 12 at a time when no frames have been accumulated in buffer 12. This reliably avoids the loss of accumulated frames that could occur if the buffer size value were adjusted when frames have been accumulated in buffer 12.

[0067] <Modified form of the third embodiment> The frame conversion device 50 of the third embodiment may be modified as follows.

[0068] <Modification 1> Modification 1 of the third embodiment corresponds to a form that combines the third embodiment and the second embodiment. The basic configuration of the frame conversion device in Modification 1 of the third embodiment is the same as that of the frame conversion device in the third embodiment, so please refer to Figure 7. For example, the adjustment unit 52 may set an initial value for the value of M (i.e., an initial value for the buffer size of buffer 12-1) based on the priority of the first destination. Alternatively, the adjustment unit 52 may set an initial value for the value of N (i.e., an initial value for the buffer size of buffer 12-2) based on the priority of the second destination.

[0069] For example, the adjustment unit 52 sets the initial value of the buffer size of buffer 12 by referring to "priority information," "initial buffer size information," and "destination buffer mapping information." The "priority information" and "destination buffer mapping information" are the same as those in the second embodiment. The "initial buffer size information" associates the priority type of a processing unit that can be associated with a processing unit with the initial buffer size corresponding to that priority type. For example, suppose there are three priority levels: high, medium, and low. In this case, the "initial buffer size information" associates, for example, initial buffer sizes 1, 2, and 3 with high, medium, and low priority levels, respectively. The "initial buffer size information" is, for example, a "initial buffer size table." The "initial buffer size table" is stored in the storage unit 14.

[0070] For example, suppose the priority information associates a high priority with the first processing unit (first destination) and a low priority with the second processing unit (second destination). In this case, the adjustment unit 52 refers to the priority information and the buffer initial size information to identify the buffer initial size "1" for the first processing unit (first destination). Then, the adjustment unit 52 refers to the "destination buffer mapping information" to identify the buffer 12-1 associated with the first processing unit (first destination) and adjusts the buffer initial size of this buffer 12-1 to "1".

[0071] By adjusting the initial value of the buffer size using this adjustment unit 52, the initial value of the buffer size of the buffer 12 associated with the destination can be adjusted to be smaller the higher the priority of the destination. This allows frames to be delivered to high-priority destinations more quickly.

[0072] Furthermore, if the first transmission amount measured by the measurement unit 51 exceeds the first threshold, the adjustment unit 52 may adjust the value of M (i.e., the buffer size of buffer 12-1) by raising the value of M from its current value to a predetermined value (for example, 1). The same applies to the value of N.

[0073] Furthermore, if the first transmission amount measured by the measurement unit 51 falls below the second threshold, the adjustment unit 52 may adjust the value of M (i.e., the buffer size of buffer 12-1) by lowering it from its current value by a predetermined value (for example, 1). The same applies to the value of N.

[0074] <Modification 2> In the third embodiment described above, the adjustment unit 52 was described as adjusting the buffer size based on the transmission amount. In contrast, in this modification 2 of the third embodiment, the priority of the destination is adjusted based on the transmission amount of the destination, and the buffer size is adjusted based on the adjusted priority. That is, modification 2 of the third embodiment corresponds to a form that combines the third embodiment and modification 1 of the second embodiment. The basic configuration of the frame conversion device in modification 2 of the third embodiment is the same as the frame conversion device in the third embodiment, so please refer to Figure 7.

[0075] The adjustment unit 52 adjusts the buffer size of buffer 12 by referring to "priority information," "buffer size information," and "destination buffer mapping information." The "destination buffer mapping information" and "buffer size information" are the same as those in Modification 1 of the second embodiment. The "priority information" associates a priority with each of several ranges corresponding to the size of the transmission amount. For example, the "priority information" may associate a priority (low, medium, high) with each of three ranges corresponding to the size of the transmission amount (large, medium, small). The "priority information" is, for example, a "priority table." The "priority table" is stored in the storage unit 14.

[0076] For example, the adjustment unit 52 refers to the "priority information" and identifies a priority corresponding to the range that includes the first transmission amount. As a result, the priority associated with the first destination (first processing unit) is adjusted according to the first transmission amount. The adjustment unit 52 then refers to the buffer size information and identifies a buffer size corresponding to the identified priority. The adjustment unit 52 then adjusts the buffer size of the buffer 12 associated with the first destination in the destination buffer mapping information to the identified buffer size.

[0077] Similarly, the adjustment unit 52 identifies a priority corresponding to the range in which the second transmission amount is included. Then, it refers to the buffer size information and identifies a buffer size corresponding to the identified priority. The adjustment unit 52 then adjusts the buffer size of the buffer 12 associated with the second destination in the destination buffer mapping information to the identified buffer size.

[0078] <Modification 3> In Modification 3 of the third embodiment, similar to Modification 2 of the third embodiment, the priority of the destination is adjusted based on the transmission amount of the destination, and the buffer size is adjusted based on the adjusted priority. In other words, Modification 3 of the third embodiment corresponds to a form that combines the third embodiment and Modification 1 of the second embodiment.

[0079] In the third embodiment, modified example 3, the "priority information" associates destinations with corresponding priorities. In other words, the "priority information" associates processing units with corresponding priorities. For example, if the first transmission amount measured by the measurement unit 51 exceeds a predetermined threshold, the adjustment unit 52 may adjust the priority of the first destination by lowering the priority of the first destination in the "priority information" by a predetermined level (for example, one level) from its current priority. The same applies to the priority of the second destination.

[0080] Furthermore, if the first transmission amount measured by the measurement unit 51 falls below the second threshold, the adjustment unit 52 may adjust the priority of the first destination in the "priority information" by raising the priority of the first destination by a predetermined level (for example, one level) from its current priority. The same applies to the priority of the second destination.

[0081] Furthermore, the adjustment unit 52 may adjust the buffer sizes of buffers 12-1 and 12-2 based on the priority of the adjusted first and second destinations, similar to the adjustment unit 42 in the modified example 1 or modified example 2 of the second embodiment.

[0082] By adjusting the destination priority using this adjustment unit 52, destinations with high transmission volumes are given higher priority, thereby increasing the buffer size of the buffer 12 associated with those destinations and increasing the number of frames output from the buffer 12. As a result, the conversion unit 13 adds a single header portion based on the second protocol to many of the frames output from the buffer 12, reducing the overhead of the header based on the second protocol. This reduces the amount of data transmitted to those destinations in the second network 30, and thus reduces the bandwidth used by the second network 30.

[0083] <Modification 4> In the above description, the buffer size or destination priority is adjusted based on the transmission volume of frames based on the second protocol in the second network 30. In contrast, the buffer size or destination priority may be adjusted based on the transmission volume of frames based on the first protocol in the first network 20.

[0084] Figure 8 is a block diagram showing an example of a frame conversion device in a modified example 4 of the third embodiment. In Figure 8, the frame conversion device 50 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, a storage unit 14, a measurement unit 54, and an adjustment unit 55.

[0085] The measurement unit 54 measures the transmission amount for frames to a first destination based on the first protocol in the first network 20, and the transmission amount for frames to a second destination based on the first protocol in the first network 20. Hereinafter, the transmission amount for frames to a first destination based on the first protocol in the first network 20 may be simply referred to as the "third transmission amount." Also, hereafter, the transmission amount for frames to a second destination based on the first protocol in the first network 20 may be simply referred to as the "fourth transmission amount."

[0086] The adjustment unit 55 adjusts the value of M (i.e., the buffer size of buffer 12-1) based on the third transmission amount measured by the measurement unit 54. For example, the adjustment unit 55 may adjust the value of M based on the third transmission amount measured by the measurement unit 54 and the "buffer size information". The "buffer size information" associates a buffer size with each of several ranges corresponding to the magnitude of the transmission amount. The adjustment unit 55 may identify the buffer size in the "buffer size information" that corresponds to the range corresponding to the third transmission amount measured by the measurement unit 54, and adjust the value of M to this buffer size. The "buffer size information" may, for example, associate different buffer sizes (3, 2, 1) with each of three ranges corresponding to the magnitude of the transmission amount (large, medium, small). The "buffer size information" is, for example, a "buffer size table". The "buffer size table" is stored in the storage unit 14.

[0087] Similarly, the adjustment unit 55 adjusts the value of N (i.e., the buffer size of buffer 12-2) based on the fourth transmission amount measured by the measurement unit 54. For example, the adjustment unit 55 may adjust the value of N to a buffer size corresponding to the range in which the fourth transmission amount is included.

[0088] Here, the amount of data transmitted in the first network 20 to a certain destination can serve as an indicator of the amount of data transmitted to that destination in the second network 30. Therefore, by adjusting by the adjustment unit 55, the buffer size of the buffer 12 associated with destinations in the second network with a large amount of data transmitted in the first network 20 can be increased, thereby increasing the number of frames output from the buffer 12 in batches. As a result, the conversion unit 13 adds a single header portion based on the second protocol to many of the frames output from the buffer 12, thus reducing the overhead of the header based on the second protocol. This reduces the amount of data transmitted to that destination in the second network 30, and thus reduces the bandwidth used by the second network 30.

[0089] The adjustment unit 55 may also set an initial value for M (i.e., an initial value for the buffer size of buffer 12-1) based on the priority of the first destination, similar to the modified example 1 of the third embodiment. Alternatively, the adjustment unit 55 may set an initial value for N (i.e., an initial value for the buffer size of buffer 12-2) based on the priority of the second destination.

[0090] Furthermore, the adjustment unit 55 does not necessarily have to directly adjust the buffer sizes of buffers 12-1 and 12-2 based on the third and fourth transmission amounts. For example, similar to the modified example 2 of the third embodiment, the priority of the first and second destinations may be adjusted based on the third and fourth transmission amounts, and the buffer sizes of buffers 12-1 and 12-2 may be adjusted indirectly based on the adjusted priority.

[0091] <Modification 5> Modification 5 of the third embodiment adjusts the buffer size or destination priority based on the transmission amount of frames based on the first protocol in the first network 20, similar to Modification 4 of the third embodiment. The basic configuration of the frame converter in Modification 5 of the third embodiment is the same as the frame converter in Modification 4 of the third embodiment, so refer to Figure 8.

[0092] For example, if the third transmission amount measured by the measurement unit 54 exceeds the first threshold, the adjustment unit 55 may adjust the value of M (i.e., the buffer size of buffer 12-1) by raising the value of M from its current value to a predetermined value (for example, 1). The same applies to the value of N.

[0093] Furthermore, if the third transmission amount measured by the measurement unit 54 falls below the second threshold, the adjustment unit 52 may adjust the value of M (i.e., the buffer size of buffer 12-1) by lowering it from its current value by a predetermined value (for example, 1). The same applies to the value of N.

[0094] The adjustment unit 55 may also set an initial value for M (i.e., an initial value for the buffer size of buffer 12-1) based on the priority of the first destination, similar to the modified example 1 of the third embodiment. Alternatively, the adjustment unit 55 may set an initial value for N (i.e., an initial value for the buffer size of buffer 12-2) based on the priority of the second destination.

[0095] Furthermore, the adjustment unit 55 does not necessarily have to directly adjust the buffer sizes of buffers 12-1 and 12-2 based on the third and fourth transmission amounts. For example, similar to the modified example 2 of the third embodiment, the priority of the first and second destinations may be adjusted based on the third and fourth transmission amounts, and the buffer sizes of buffers 12-1 and 12-2 may be adjusted indirectly based on the adjusted priority.

[0096] <Modification 6> In the third embodiment described above, the value of M (i.e., the buffer size of buffer 12-1) is adjusted based on the first transmission amount, and the value of N (i.e., the buffer size of buffer 12-2) is adjusted based on the second transmission amount. In modification 6 of this third embodiment, the timing of adjusting the value of M is controlled based on the third transmission amount, and the timing of adjusting the value of M (i.e., the buffer size of buffer 12-1) is controlled based on the fourth transmission amount.

[0097] Figure 9 is a block diagram showing an example of a frame conversion device in a modified example 6 of the third embodiment. In Figure 9, the frame conversion device 50 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, a storage unit 14, a measuring unit 51, a measuring unit 54, and an adjustment unit 56.

[0098] The adjustment unit 56 controls the timing for adjusting the value of M based on the third transmission amount. Specifically, the adjustment unit 56 may predict the situation in which frames are accumulated in buffer 12-1 based on the third transmission amount, and control the timing for adjusting the value of M based on the predicted situation. For example, the adjustment unit 56 may predict a timing when there are few frames accumulated in buffer 12-1 based on the third transmission amount, and at that timing, adjust the value of M (i.e., the buffer size of buffer 12-1) based on the first transmission amount.

[0099] Furthermore, the adjustment unit 56 controls the timing of adjusting the value of N based on the fourth transmission amount. Specifically, the adjustment unit 56 may predict the situation in which frames are accumulated in the buffer 12-2 based on the fourth transmission amount, and control the timing of adjusting the value of N based on the predicted situation. For example, the adjustment unit 56 may predict a timing when there are few frames accumulated in the buffer 12-2 based on the fourth transmission amount, and at that timing, adjust the value of N (i.e., the buffer size of buffer 12-2) based on the second transmission amount.

[0100] As described above, if the buffer size is adjusted at the time when frames are being stored in buffer 12, there is a possibility that stored frames will be lost. In response to this, the adjustment unit 56 predicts the timing when there are few frames stored in buffer 12-1 based on the third transmission amount, and at that timing, adjusts the value of M (i.e., the buffer size of buffer 12-1) based on the first transmission amount. Similarly, the adjustment unit 56 predicts the timing when there are few frames stored in buffer 12-2 based on the fourth transmission amount, and at that timing, adjusts the value of N (i.e., the buffer size of buffer 12-2) based on the second transmission amount. As a result, the adjustment unit 56 can adjust the buffer size at the timing when there are few frames stored in buffer 12, thereby reducing the risk of stored frames being lost.

[0101] <Fourth Embodiment> The fourth embodiment relates to an embodiment in which the buffer size is adjusted based on the condition of the vehicle or the environment in which the vehicle is located.

[0102] Figure 10 is a block diagram showing an example of a frame conversion device in the fourth embodiment. In Figure 10, the frame conversion device 60 includes a distribution unit 11, buffers 12-1 and 12-2, a conversion unit 13, a storage unit 14, a determination unit 61, an adjustment unit 62, and a sensor 63. The basic configuration of the system in the fourth embodiment is the same as that of system 1 shown in Figure 1. That is, system 1 in the fourth embodiment has a frame conversion device 60 instead of a frame conversion device 10. Furthermore, the fourth embodiment assumes that system 1 is installed in a vehicle. For the sake of simplicity, the number of buffers 12 in the frame conversion device 60 is assumed to be two, but it is not limited to this. That is, the number of buffers 12 in the frame conversion device 60 may be three or more. Even in this case, the three or more buffers 12 are each associated with a different destination.

[0103] In the fourth embodiment, the destination buffer mapping information associates the first destination with buffer 12-1 and the second destination with buffer 12-2. In other words, the fourth embodiment assumes that the destination buffer mapping information is fixed.

[0104] The determination unit 61 determines the state of the system 1, that is, the vehicle on which the frame conversion device 60 is installed, based on the sensing information from the sensor 63. The state of the vehicle to be determined is, for example, the current driving state and the stopped state of the vehicle. For example, the sensor 63 may be a sensor that detects the rotation speed of the vehicle's axles. In this case, the determination unit 61 can determine that the current state of the vehicle is driving if the detected axle rotation speed is not zero. On the other hand, the determination unit 61 can determine that the current state of the vehicle is stopped if the detected axle rotation speed is zero. The determination unit 61 may also predict the state of the vehicle in the near future, instead of the current state of the vehicle, or in addition to the current state of the vehicle.

[0105] The adjustment unit 62 adjusts the buffer size of at least one of the buffers 12-1 and 12-2 based on the vehicle state determined by the determination unit 61. For example, the first destination is associated with a processing unit that handles data related to a first operation performed on the vehicle, and the second destination is associated with a processing unit that handles data related to a second operation performed on the vehicle. The adjustment unit 62 then adjusts the buffer size of buffer 12-1 associated with the first destination based on the vehicle state determined by the determination unit 61 and the "buffer size information". The "buffer size information" includes, for example, information on multiple buffer sizes corresponding to multiple vehicle states for each buffer 12. The adjustment unit 62 adjusts the buffer size of buffer 12-1 to the buffer size associated with the vehicle state determined by the determination unit 61 for buffer 12-1 in the "buffer size information". The "buffer size information" is, for example, a "buffer size table". The "buffer size table" is stored in the storage unit 14.

[0106] Similarly, the adjustment unit 62 may adjust the buffer size of buffer 12-2 associated with the second destination based on the vehicle status determined by the determination unit 61. For example, the adjustment unit 62 adjusts the buffer size of buffer 12-2 associated with the second destination based on the vehicle status determined by the determination unit 61 and the "buffer size information". Specifically, the adjustment unit 62 adjusts the buffer size of buffer 12-2 to the buffer size associated with the vehicle status determined by the determination unit 61 for buffer 12-2 in the "buffer size information".

[0107] For example, reclining operations are more likely to be performed when the vehicle is stationary and less likely to be performed when it is in motion. Therefore, the number of frames sent to the destination (processing unit) that handles data related to reclining operations tends to be higher when the vehicle is stationary and lower when it is in motion. Here, the destination that handles data related to reclining operations is the first destination associated with buffer 12-1. In this case, the "buffer size information" associates buffer 12-1 with a buffer size of "3" when stationary and a buffer size of "1" when in motion. By using this buffer size information, the adjustment unit 62 adjusts to increase the buffer size of buffer 12-1 when it is determined that the vehicle is stationary. On the other hand, the adjustment unit 62 adjusts to decrease the buffer size of buffer 12-1 when it is determined that the vehicle is in motion. In this way, the buffer size of buffer 12 associated with the destination where the amount of transmission is expected to be large in the determined state is increased, and the number of frames output in batches from buffer 12 can be increased. Therefore, since the conversion unit 13 adds a single header portion based on the second protocol to many frames output from the buffer 12, the overhead of the header based on the second protocol can be reduced. As a result, the amount of data transmitted to its destination in the second network 30 can be reduced, and thus the bandwidth used by the second network 30 can be reduced.

[0108] Here, the destination with the most frames changes depending on the type of vehicle state. In other words, the type of vehicle state can serve as an indicator of the amount of frames transmitted for each destination. For this reason, by adjusting the buffer size by the adjustment unit 62, the buffer size of the buffer 12 associated with destinations that are expected to have a large transmission amount in the determined state is increased, and the number of frames output from buffer 12 in batches can be increased. As a result, the conversion unit 13 adds one header portion based on the second protocol to many of the frames output from buffer 12, thereby reducing the overhead of the header based on the second protocol. This reduces the amount of transmission to that destination in the second network 30, and thus reduces the bandwidth used by the second network 30.

[0109] <Variation> The frame conversion device 60 of the fourth embodiment may be modified as follows.

[0110] The basic configuration of the frame conversion device in the modified version of the fourth embodiment is the same as that of the frame conversion device in the fourth embodiment, so please refer to Figure 10.

[0111] In the modified version of the fourth embodiment, the determination unit 61 determines the environment in which the system 1, that is, the vehicle on which the frame conversion device 60 is installed, is located, based on the sensing information of the sensor 63. The environment in which the vehicle is located that is determined is, for example, the current weather condition, such as rainy weather and non-rainy weather (e.g., sunny weather). For example, the sensor 63 may be a sensor that detects whether the vehicle's wipers are on or off. In this case, if the determination unit 61 detects that the wipers are on, it can determine that the current environment in which the vehicle is located is rainy. On the other hand, if the determination unit 61 detects that the wipers are off, it can determine that the current environment in which the vehicle is located is not rainy. The determination unit 61 may also predict the environment in which the vehicle will be located in the near future, in addition to or instead of the current environment in which the vehicle is located.

[0112] The adjustment unit 62 adjusts the buffer size of at least one of the buffers 12-1 and 12-2 based on the environment in which the vehicle is located, as determined by the determination unit 61. For example, the first destination is associated with a processing unit that handles data related to a third operation performed on the vehicle, and the second destination is associated with a processing unit that handles data related to a fourth operation performed on the vehicle. The adjustment unit 62 then adjusts the buffer size of buffer 12-1, which is associated with the first destination, based on the environment in which the vehicle is located, as determined by the determination unit 61, and the "buffer size information". The "buffer size information" includes, for example, information on multiple buffer sizes corresponding to multiple vehicle environments for each buffer 12. The adjustment unit 62 adjusts the buffer size of buffer 12-1 to the buffer size associated with the vehicle environment determined by the determination unit 61 for buffer 12-1 in the "buffer size information". The "buffer size information" is, for example, a "buffer size table". The "buffer size table" is stored in the storage unit 14.

[0113] Similarly, the adjustment unit 62 adjusts the buffer size of buffer 12-2 associated with the second destination based on the environment in which the vehicle is located, as determined by the determination unit 61. For example, the adjustment unit 62 adjusts the buffer size of buffer 12-2 associated with the second destination based on the state of the vehicle determined by the determination unit 61 and the "buffer size information".

[0114] For example, wiper operation is more likely to occur in rainy conditions and less likely in dry conditions. Therefore, the number of frames sent to the destination (processing unit) that handles data related to wiper operation tends to be higher in rainy conditions and lower in dry conditions. Here, the destination that handles data related to wiper operation is the first destination associated with buffer 12-1. In this case, the "buffer size information" associates buffer 12-1 with a buffer size of "3" in rainy conditions and a buffer size of "1" in dry conditions. By using this buffer size information, the adjustment unit 62 adjusts to increase the buffer size of buffer 12-1 when it is determined to be in a rainy environment. On the other hand, the adjustment unit 62 adjusts to decrease the buffer size of buffer 12-1 when it is determined to be in a dry environment. In this way, the buffer size of buffer 12 associated with the destination where the transmission volume is expected to be high in the determined environment in which the vehicle is located can be increased, thereby increasing the number of frames output in batches from buffer 12. Therefore, since the conversion unit 13 adds a single header portion based on the second protocol to many frames output from the buffer 12, the overhead of the header based on the second protocol can be reduced. As a result, the amount of data transmitted to its destination in the second network 30 can be reduced, and thus the bandwidth used by the second network 30 can be reduced.

[0115] Here, the destination with the most frames changes depending on the type of environment in which the vehicle is located. In other words, the type of environment in which the vehicle is located can serve as an indicator of the amount of frames transmitted for each destination. For this reason, by adjusting the buffer size by the adjustment unit 62, the buffer size of the buffer 12 associated with destinations that are expected to have a large transmission volume in the determined environment in which the vehicle is located is increased, thereby increasing the number of frames that can be output in batches from buffer 12. As a result, the conversion unit 13 adds a single header portion based on the second protocol to many of the frames output from buffer 12, thereby reducing the overhead of the header based on the second protocol. This reduces the amount of transmission to that destination in the second network 30, and thus reduces the bandwidth used by the second network 30.

[0116] The frame conversion devices 10, 40, 50, and 60 of the first to fourth embodiments described above can each have the configuration shown in Figure 11. Figure 11 is a diagram showing an example of the configuration of a frame conversion device. In Figure 11, the frame conversion device 100 has a processor 101 and a memory 102. The processor 101 may be, for example, a microprocessor, an MPU (Micro Processing Unit), or a CPU (Central Processing Unit). The processor 101 may include multiple processors. The memory 102 is composed of a combination of volatile memory and non-volatile memory. The memory 102 may include storage located away from the processor 101. In this case, the processor 101 may access the memory 102 via an I / O (Input / Output) interface, which is not shown. The distribution unit 11, conversion unit 13, adjustment units 41, 42, 43, 52, 53, 55, 62, 64, measurement units 51, 54, and determination units 61, 63 of the frame conversion devices 10, 40, 50, 60 in the first to fourth embodiments may be implemented by the processor 101 reading and executing a program stored in memory 102. In other words, the frame conversion devices 10, 40, 50, 60 in the first to fourth embodiments can be implemented in software. Buffers 12-1, 12-2 may be implemented by memory 102. The program can be stored using various types of non-transitory computer-readable medium and supplied to the frame conversion devices 10, 40, 50, 60. Examples of non-transitory computer-readable medium include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives) and magneto-optical recording media (e.g., magneto-optical disks). Furthermore, examples of non-temporary computer-readable media include CD (Compact Disc)-ROM (Read Only Memory), CD-R, and CD-R / W. Additionally, examples of non-temporary computer-readable media include semiconductor memory.Semiconductor memory includes, for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, and RAM (Random Access Memory). The program may also be supplied to the frame converters 10, 40, 50, and 60 by various types of transient computer-readable medium. Examples of transient computer-readable medium include electrical signals, optical signals, and electromagnetic waves. The transient computer-readable medium can supply the program to the frame converters 10, 40, 50, and 60 via wired communication channels such as electric wires and optical fibers, or via wireless communication channels.

[0117] However, the frame conversion devices 10, 40, 50, and 60 described in the first to fourth embodiments can also be implemented using hardware (circuits). That is, the distribution unit 11, the conversion unit 13, the adjustment units 41, 42, 43, 52, 53, 55, 62, and 64, the measurement units 51 and 54, and the determination units 61 and 63 of the frame conversion devices 10, 40, 50, and 60 in the first to fourth embodiments may be implemented using circuits.

[0118] The present invention has been described in detail above based on embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0119] 1 System 10 Frame conversion device 11 Distribution section 12 buffers 13 Conversion section 20 First Network 21 Processing Modules 30 Second Network 31 Processing Units 40-frame converter 41 Adjustment part 42 Adjustment part 50 Frame Converter 51 Measuring part 52 Adjustment section 54 Measuring part 55 Adjustment section 60-frame converter 61 Judgment section 62 Adjustment section 63 Sensors

Claims

1. A program that causes a frame conversion device, which is disposed between a first network based on a first protocol and a second network based on a second protocol, to perform processing, The aforementioned process is, The first buffer holds the allocated frames, and when the number of held frames reaches M, the M frames are output together. The second buffer holds the allocated frames, and when the number of held frames reaches N, the N frames are output together. Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The aforementioned process is, To measure the first transmission amount for the frame to the first destination based on the second protocol in the second network, and the second transmission amount for the frame to the second destination based on the second protocol in the second network, Based on the first transmission amount, the value of M is adjusted, and based on the second transmission amount, the value of N Adjusting the values, It further includes, The aforementioned process is, To measure the third transmission amount for the frame to the first destination based on the first protocol in the first network, and the fourth transmission amount for the frame to the second destination based on the first protocol in the first network, Based on the third transmission amount, predict the situation in which frames are accumulated in the first buffer and control the timing of adjusting the value of M. Based on the fourth transmission amount, predict the situation in which frames are accumulated in the second buffer and control the timing of adjusting the value of N. Further including, program.

2. A program that causes a frame conversion device, which is disposed between a first network based on a first protocol and a second network based on a second protocol, to perform processing, The aforementioned process is, The first buffer holds the allocated frames, and when the number of held frames reaches M, the M frames are output together. The second buffer holds the allocated frames, and when the number of held frames reaches N, the N frames are output together. Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The aforementioned process is, Adjust the value of M based on the priority of the first destination, Based on the priority of the second destination, adjust the value of N, To measure the first transmission amount for the frame to the first destination based on the second protocol in the second network, and the second transmission amount for the frame to the second destination based on the second protocol in the second network, It further includes, Adjusting the value of M includes adjusting the priority of the first destination based on the first transmission amount. Adjusting the value of N includes adjusting the priority of the second destination based on the second transmission amount. program.

3. A program that causes a frame conversion device, which is disposed between a first network based on a first protocol and a second network based on a second protocol, to perform processing, The aforementioned process is, The first buffer holds the allocated frames, and when the number of held frames reaches M, the M frames are output together. The second buffer holds the allocated frames, and when the number of held frames reaches N, the N frames are output together. Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The aforementioned process is, Based on the priority of the first destination and the priority of the second destination, the values ​​of M and N are adjusted. To measure the first transmission amount for the frame to the first destination based on the second protocol in the second network, and the second transmission amount for the frame to the second destination based on the second protocol in the second network, It further includes, Adjusting the value of M and the value of N includes adjusting the priority of the first destination and the priority of the second destination based on the first transmission amount and the second transmission amount. program.

4. A program that causes a frame conversion device, which is disposed between a first network based on a first protocol and a second network based on a second protocol, to perform processing, The aforementioned process is, The first buffer holds the allocated frames, and when the number of held frames reaches M, the M frames are output together. The second buffer holds the allocated frames, and when the number of held frames reaches N, the N frames are output together. Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. The first network, the second network, and the frame conversion device are installed in the vehicle. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The aforementioned process is, The state of the vehicle is determined from among multiple candidate states, including driving and stationary states, based on sensor information. Based on the determined state, adjust at least one of the values ​​of M and N. Further including, program.

5. The first destination is associated with the first operation performed in the vehicle, The second destination is associated with the second operation performed in the vehicle, The aforementioned adjustments are, If the state of the vehicle is determined to be the first state, the value of M is increased. If the vehicle's condition is determined to be the second state, an adjustment is made to reduce the value of M. including, The program according to claim 4.

6. A program that causes a frame conversion device, which is disposed between a first network based on a first protocol and a second network based on a second protocol, to perform processing, The aforementioned process is, The first buffer holds the allocated frames, and when the number of held frames reaches M, the M frames are output together. The second buffer holds the allocated frames, and when the number of held frames reaches N, the N frames are output together. Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. The first network, the second network, and the frame conversion device are installed in the vehicle. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The aforementioned process is, From among the candidate environments in which the vehicle is placed, including rainy and non-rainy conditions, the environment in which the vehicle is placed is determined based on sensor information. Based on the determined environment, adjust at least one of the values ​​of M and N. Further including, program.

7. The first destination is associated with the third operation performed in the vehicle, The second destination is associated with the fourth operation performed in the vehicle, The aforementioned adjustments are, If it is determined that the environment in which the vehicle is located is the first environment, the value of M is increased. If it is determined that the environment in which the vehicle is located is the second environment, an adjustment is made to reduce the value of M. including, The program according to claim 6.

8. A frame conversion device disposed between a first network based on a first protocol and a second network based on a second protocol, A first buffer holds the allocated frames, and when the number of held frames reaches M, it outputs the M frames together. A second buffer holds the allocated frames, and when the number of held frames reaches N, it outputs the N frames together. A distribution unit that distributes frames based on the first protocol to the first buffer and the second buffer based on the correspondence between the first and second destinations of the frames based on the first protocol and the first buffer and the second buffer, A conversion unit that adds a header based on the second protocol and containing a destination corresponding to the first buffer in the correspondence relationship to the entire M frames output from the first buffer, thereby forming a frame based on the second protocol, and outputs the frame based on the second protocol to the second network; and adds a header based on the second protocol and containing a destination corresponding to the second buffer in the correspondence relationship to the entire N frames output from the second buffer, thereby forming a frame based on the second protocol, and outputs the frame based on the second protocol to the second network; It is equipped with, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The frame conversion device is, An adjustment unit that adjusts the value of M based on the priority of the first destination and adjusts the value of N based on the priority of the second destination, A measuring unit that measures a first transmission amount for a frame to the first destination based on the second protocol in the second network, and a second transmission amount for a frame to the second destination based on the second protocol in the second network, Furthermore, it is equipped with, The adjustment unit is, The value of M is adjusted by adjusting the priority of the first destination based on the first transmission amount. The value of N is adjusted by adjusting the priority of the second destination based on the second transmission amount. Frame conversion device.

9. A frame conversion device disposed between a first network based on a first protocol and a second network based on a second protocol, A first buffer holds the allocated frames, and when the number of held frames reaches M, it outputs the M frames together. A second buffer holds the allocated frames, and when the number of held frames reaches N, it outputs the N frames together. A distribution unit that distributes frames based on the first protocol to the first buffer and the second buffer based on the correspondence between the first and second destinations of the frames based on the first protocol and the first buffer and the second buffer, A conversion unit that adds a header based on the second protocol and containing a destination corresponding to the first buffer in the correspondence relationship to the entire M frames output from the first buffer, thereby forming a frame based on the second protocol, and outputs the frame based on the second protocol to the second network; and adds a header based on the second protocol and containing a destination corresponding to the second buffer in the correspondence relationship to the entire N frames output from the second buffer, thereby forming a frame based on the second protocol, and outputs the frame based on the second protocol to the second network; It is equipped with, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The frame conversion device is, An adjustment unit that adjusts the value of M and the value of N based on the priority of the first destination and the priority of the second destination, A measuring unit that measures a first transmission amount for a frame to the first destination based on the second protocol in the second network, and a second transmission amount for a frame to the second destination based on the second protocol in the second network, Furthermore, it is equipped with, The adjustment unit adjusts the value of M and the value of N by adjusting the priority of the first destination and the priority of the second destination based on the first transmission amount and the second transmission amount. Frame conversion device.

10. A method comprising a frame conversion device disposed between a first network based on a first protocol and a second network based on a second protocol, Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, The first buffer holds the allocated frames, and when the number of held frames reaches M, it outputs the M frames together. The second buffer holds the allocated frames, and when the number of held frames reaches N, it outputs the N frames together. A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The method involves adjusting the value of M based on the priority of the first destination, Based on the priority of the second destination, adjust the value of N, To measure the first transmission amount for the frame to the first destination based on the second protocol in the second network, and the second transmission amount for the frame to the second destination based on the second protocol in the second network, It further includes, Adjusting the value of M includes adjusting the priority of the first destination based on the first transmission amount. Adjusting the value of N includes adjusting the priority of the second destination based on the second transmission amount. method.

11. A method comprising a frame conversion device disposed between a first network based on a first protocol and a second network based on a second protocol, Based on the correspondence between the first and second destinations of the frame based on the first protocol and the first and second buffers, the frame based on the first protocol is distributed to the first and second buffers, The first buffer holds the allocated frames, and when the number of held frames reaches M, it outputs the M frames together. The second buffer holds the allocated frames, and when the number of held frames reaches N, it outputs the N frames together. A frame based on the second protocol is formed by adding a header, which is a header based on the second protocol and includes a destination corresponding to the first buffer in the correspondence relationship, to the entirety of the M frames output from the first buffer, and the frame based on the second protocol is output to the second network. A frame based on the second protocol is formed by adding a single header, which is a header based on the second protocol and includes a destination associated with the second buffer in the correspondence relationship, to the entirety of the N frames output from the second buffer, and the frame based on the second protocol is output to the second network. Includes, The values ​​of M and N are each integers of 1 or more. At least one of the values ​​of M and N is an integer of 2 or more. In the aforementioned correspondence, the first destination is associated with the first buffer, and the second destination is associated with the second buffer. The method involves adjusting the value of M and the value of N based on the priority of the first destination and the priority of the second destination. To measure the first transmission amount for the frame to the first destination based on the second protocol in the second network, and the second transmission amount for the frame to the second destination based on the second protocol in the second network, It further includes, Adjusting the value of M and the value of N includes adjusting the priority of the first destination and the priority of the second destination based on the first transmission amount and the second transmission amount. method.

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