Transfer device, transfer method, and transfer program

Abstract

A transfer device (10) transfers a reception frame. A frame identification unit (121) assigns a corresponding identifier to the reception frame on the basis of the content in the reception frame. An allocation unit (122) stores the reception frame in a reception queue (123) corresponding to the identifier assigned to the reception frame. A reception gate control unit (124) executes a reception gate control process to read the reception frame from the reception queue (123) on the basis of a gate control setting that is set by a setting unit (104), the gate control setting being adapted for causing the reception queue to wait for a reception frame that has caused a cycle violation of a communication cycle.

Description

Technical Field

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

Background Art

[0002] In IEEE802.1Q-2018, TAS is defined. TAS is an abbreviation for Time-Aware Shaper. TAS is a specification of a transfer device for ensuring the transmission quality of each communication stream in a network where communication streams with different required quality levels coexist. In TAS, schedule transfer based on synchronized time within the network is performed. However, when a communication stream that violates the communication cycle defined in the network design stage occurs, the schedule transfer by TAS fails. To solve this problem, also in IEEE802.1Q-2018, PSFP is defined as a specification for discarding a communication stream with a cycle violation at the receiving time by the transfer device. PSFP is an abbreviation for Per-Stream Filtering and Policing.

[0003] Also, in IEEE802.1Q-2018, FP is defined as a specification of a transfer device for guaranteeing the delay of a high-priority communication stream. FP is an abbreviation for Frame Preemption. In FP, when a transfer request for a high-priority frame that requires low-latency transfer occurs during the transfer of a low-priority frame that does not require low-latency transfer, the transfer of the low-priority frame is interrupted and split, and the high-priority frame is transferred by interrupt transfer, thereby reducing the transfer delay of the high-priority frame. The low-priority frame split by the interrupt transfer is transferred after the transfer of the high-priority frame is completed and is combined at the receiving transfer device to be restored to the frame before splitting.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the transfer device supporting PSFP, the transmission quality of communication streams that do not violate the period is ensured. However, communication streams that violate the period are only discarded, and the transmission quality is not ensured. In order for terminals not to cause period violations in communication streams, it is necessary to synchronize time with high precision between terminals and perform advanced transmission timing control using the synchronized time. However, advanced transmission timing control using synchronized time generally increases the terminal cost. When terminals that can control transmission timing with high precision cannot be used, in the transfer control by PSFP, the problem is that the transmission quality of communication streams with large transmission timing errors cannot be ensured.

[0006] The present disclosure aims to relax the required accuracy of transmission timing synchronization of terminals and reduce the terminal cost.

Means for Solving the Problems

[0007] The transfer device according to the present disclosure includes a frame identifier unit that assigns a corresponding identifier to a received frame based on the content of the received frame; a distribution unit that stores the received frame in a reception queue corresponding to the identifier assigned to the received frame; a gate control setting unit that sets open / close information of the reception queue, and sets a gate control setting for waiting a received frame that violates the communication period in the reception queue; a reception gate control unit that executes a reception gate control process for reading a received frame from the reception queue based on the gate control setting and is provided with.

Effects of the Invention

[0008] In the transfer device according to the present disclosure, the received frame is read from the receive queue based on the gate control setting that causes the received frame with a cycle violation in the communication cycle to wait in the receive queue. Therefore, according to the transfer device according to the present disclosure, by absorbing the transmission timing error of the terminal in the transfer device, the required accuracy of the transmission timing synchronization of the terminal can be relaxed, and it is possible to contribute to the reduction of the terminal cost.

Brief Description of the Drawings

[0009]

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Modes for Carrying Out the Invention

[0010] Hereinafter, this embodiment will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. In the description of the embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate. The arrows in the figures mainly indicate the flow of data or the flow of processing. Also, in the following figures, the relationship of the sizes of the respective components may be different from the actual ones. Further, in the description of the embodiment, directions or positions such as up, down, left, right, front, back, front side, and back side may be shown. These notations are for convenience of explanation and do not limit the arrangement, direction, and orientation of the device, instrument, or parts, etc.

[0011] Embodiment 1. FIG. 1 is a diagram showing the failure of schedule transfer by TAS. FIG. 2 is a diagram showing an overview of the operation of a transfer device that supports PSFP. FIGS. 1 and 2 show examples of transfer devices that are the premise of this embodiment.

[0012] In the TAS shown in FIG. 1, schedule transfer is performed based on the time synchronized within the network. However, as shown in FIG. 1, when a communication stream that violates the communication cycle defined at the network design stage occurs, the schedule transfer by TAS fails.

[0013] As shown in FIG. 2, by the transfer device supporting PSFP, the transmission quality of communication stream #1 that does not violate the cycle is ensured. However, communication stream #2 that violates the cycle is only discarded and the transmission quality is not ensured.

[0014] ***Description of the configuration*** FIG. 3 is a diagram showing a functional configuration example of the transfer device 10 according to this embodiment.

[0015] As shown in FIG. 3, the transfer device 10 includes a port 101, a reception unit 102, a transmission unit 103, and a setting unit 104. The receiving unit 102 includes a frame identification unit 121, a demultiplexing unit 122, a reception queue 123, a reception gate control unit 124, and a multiplexing unit 125. The transmitting unit 103 includes a separation unit 131, a transmission queue 132, and a transmission gate control unit 133. Note that the number of these functional blocks does not need to be limited to the number shown in FIG. 3, and each number may be more or less than the number in FIG. 3.

[0016] ***Explanation of Operations*** Next, the operation of the transfer device 10 according to the present embodiment will be described. The operation procedure of the transfer device 10 corresponds to the transfer method. Also, the program for realizing the operation of the transfer device 10 corresponds to the transfer program.

[0017] FIG. 4 is a diagram showing an overall configuration example of the transfer system 500 according to the present embodiment and an overview of the operation of the transfer device 10. As shown in FIG. 4, in the transfer system 500, the transfer device transfers communication streams transmitted and received between terminals. In the transfer system of FIG. 2, the communication stream #2 that violated the period was discarded, and the transmission quality was not ensured. On the other hand, in the transfer system 500 according to the present embodiment, the transfer device 10 can transfer the communication stream #1 and the communication stream #2 as scheduled by queuing and waiting for the frames that violate the period.

[0018] The port 101 transfers the received frame received from the external device to the frame identification unit 121.

[0019] Based on the content of the received frame received from the port 101, the frame identification unit 121 assigns a corresponding identifier to the received frame. The identifier determines a unique identifier by pattern matching between the attributes of the received frame and the settings acquired from the setting unit 104. The attributes of the received frame are attributes such as the reception port number, header information, payload information, and error information of the received frame.

[0020] The setting unit 104 sets setting information for determining an identifier. Also, the setting unit 104 sets gate control settings. Also, the setting unit 104 enables setting either the branch port type or the trunk port type for each port that receives a received frame.

[0021] The setting information is, for example, a setting such that when the destination MAC address of a received frame received at port number 1 is "12-34-56-AB-CD-EF" and the EtherType is "0x0800" (IP communication), ID=1 is assigned. Note that MAC is an abbreviation for Media Access Control. IP is an abbreviation for Internet Protocol. ID is an abbreviation for Identifier. At this time, the frame identification unit 121 determines whether the received frame matches the above settings, and if it matches, assigns ID=1 to the received frame. The assignment of the identifier to the received frame may be performed by temporarily replacing a part of the frame content within the transfer device. Or, a signal indicating the identifier may be transmitted in parallel with the received frame separately from the received frame and transferred to the subsequent functional block. Also, the identification condition may be set by the user in the setting unit 104 as described above, or the identification condition may be statically recorded in the frame identification unit 121. The gate setting control and the port type setting will be described later.

[0022] The distribution unit 122 receives the received frame from the frame identification unit 121. The distribution unit 122 transfers the received frame to the receive queue 123 corresponding to the identifier based on the identifier assigned to the received frame by the frame identification unit 121. Specifically, when the transfer device 10 has a reception queue corresponding to the identifier attached to the received frame, the distribution unit 122 stores the received frame in the corresponding reception queue. On the other hand, when the transfer device 10 does not have the corresponding reception queue, the received frame is transmitted to the reception gate control unit 124. That is, when the transfer device 10 does not have the corresponding reception queue, general PSFP processing is performed.

[0023] The reception queue 123 temporarily stores the received frames received from the distribution unit 122. The reception queue 123 transmits information on whether there is frame accumulation and the frame length of the head frame of the queue to the reception gate control unit 124. It is not necessary to provide one reception queue for each identifier. For example, by associating a plurality of identifiers with one reception queue, it is also possible to provide fewer reception queues than the number of identifiers that can be set in the transfer device 10. Also, a transfer device equipped with an FP function usually has a reception queue for combining the divided frames, but the reception queue 123 may also divert the reception queue used for this FP function.

[0024] The reception gate control unit 124 executes reception gate control processing for reading the received frame from the reception queue 123 based on the gate control setting set in the setting unit 104. In the reception gate control unit 124, when a frame is accumulated in the reception queue 123 based on the gate control setting, the frame is read from the reception queue 123. Specifically, as reception gate control processing, the reception gate control unit 124 selects either an operation of queuing or discarding based on the difference between the gate control setting and the arrival timing of the received frame. That is, transfer or discard is selected according to the degree of cycle violation.

[0025] The gate control setting sets the open / close information of the reception queue. The gate control setting is information for waiting for the received frame that causes a cycle violation in the communication cycle in the reception queue. FIG. 5 is a diagram showing a structural example of the gate control setting according to the present embodiment. FIG. 6 is a diagram showing an example of a gate opening / closing operation based on the gate control setting according to the present embodiment. The gate control setting has a list structure and is composed of a list index, opening / closing information of the reception queue, and time. The opening / closing information of the reception queue is the opening / closing information for each reception queue and has a value of 0 or 1. 0 indicates a state in which reading from the reception queue is prohibited. Also, 1 indicates a state in which reading from the reception queue is permitted. The set value of time is the time when reading is permitted. The set value of time is set as, for example, an integer value in nanoseconds. The gate control setting with index = 1 in FIG. 5 indicates that reading from reception queue 1 is permitted for 512 nanoseconds.

[0026] The reception gate control unit 124 sequentially refers to the gate control settings in ascending order of the index, reads frames only from the reception queues for which reading is permitted at the current time, and transfers them to the multiplexing unit 125. When there are a plurality of reception queues for which reading is permitted, the reception queue to be read is determined according to a specific rule. Specifically, the reception-side gate control unit 1024 reads reception frames from reception queue 1 for 512 ns with index = 1, and then reads reception frames from reception queues 1 and 2 for 256 ns with index = 2, and repeats the process. Examples of the specific rule include, for example, the strict priority rule or the round-robin rule. The strict priority rule is a rule for preferentially reading frames in ascending order of the reception queue number. The round-robin rule is a rule for switching the reception queue to be read at regular intervals. When the gate control setting to be referred to by the reception gate control unit 124 reaches the end of the list, it refers to the beginning of the list again in order.

[0027] When the transfer device 10 does not have a reception queue corresponding to the identifier, the distribution unit 122 does not store the reception frame in the reception queue 123 but transfers it to the reception gate control unit 124. The reception gate control unit 124 receives from the setting unit 104 the gate control settings for each identifier of the received frame, similar to the gate control settings for each reception queue as shown in FIG. 5. Then, the reception gate control unit 124 discards at the reception gate control unit 124 the frames whose reading is prohibited at the current time. The gate control settings for each identifier of the frame, which are similar to the gate control settings for each reception queue, are specifically settings such as for how many seconds the frame with ID = 1, for how many seconds the frame with ID = 2, and so on. Note that the reference of the gate control settings for each reception queue and the reference of the gate control settings for each frame identifier are executed in parallel.

[0028] Note that the reception gate control unit 124 does not necessarily have to strictly follow the time information of the gate control settings. The setting unit 104 separately sets time information indicating an allowable error, and if the time within the range where reading is permitted and the current time are within the range of the allowable error, the frame may be transferred without being discarded. Also, even if the time when reading is permitted and the current time are outside the range of the allowable error, if frames are accumulated in the reception queue, these accumulated frames may not be transferred to the multiplexing unit 125 and may be discarded. By considering such an allowable error, clearly periodic violation frames can be discarded, and the effect of reducing the usage bandwidth of the network can be obtained. As described above, the reception gate control unit 124 causes the frames for which the transmission timing of the terminal is not as scheduled, that is, not as per the gate control settings, to wait in the reception queue until the time when transfer is permitted by the gate control settings. Thereby, the transfer device can absorb the transmission timing error of the terminal and relax the required accuracy of the transmission timing synchronization of the terminal.

[0029] The setting unit 104 enables the setting of the types of "branch port" and "trunk port" for each port of the transfer device 10. The set value of this port type is transmitted to the reception unit 102. The "branch port" is, for example, a port connected to a terminal. The "trunk port" is, for example, a port connected to another transfer device 10. The ports set as branch ports execute the above-described reception gate control process, and the ports set as trunk ports do not execute the reception gate control process but execute normal transfer control.

[0030] In the ports set as trunk ports, the process of the frame discrimination unit 121 assigning the identifier referred to by the distribution unit 122 is omitted. Then, the distribution unit 122 does not store the frame in the reception queue 123 and transfers it to the reception gate control unit 124. And the gate control process in the reception gate control unit 124 can also be omitted. The reason is as follows. When reception gate control processing is performed at the branch port to absorb the transmission timing error of the terminal, the normality of the transfer schedule of each communication stream is guaranteed at the trunk port. For this reason, the process for absorbing the transmission timing error is not required at the trunk port. By omitting the reception gate control process at the trunk port, the effect of reducing the calculation cost and the effect of reducing the transfer delay of the communication stream at the trunk can be obtained.

[0031] In the multiplexing unit 125, a plurality of frames received from the reception gate control units of each port are multiplexed. In the separation unit 131, they are stored in the transmission queue 132 of the port corresponding to the destination of the received frame. The transmission queue 132 and the transmission gate control unit perform scheduling transfer control according to the TAS defined in IEEE802.1Q-2018.

[0032] ***Description of Hardware Configuration Example*** The transfer device 10 is a computer. In the transfer device 10, the functions of the reception unit 102, the transmission unit 103, and the setting unit 104 are realized by hardware, software, firmware, or a combination thereof.

[0033] <Realized by software> FIG. 7 is a diagram showing a hardware configuration example of the transfer device 10 according to the present embodiment. The transfer device 10 is a computer. The transfer device 10 includes a processor 910 and other hardware such as a memory 921, an auxiliary storage device 922, an input / output interface 930, and a communication interface 950. The processor 910 is connected to the other hardware via a signal line 80 and controls these other hardware components.

[0034] As described above, the transfer device 10 includes, as functional elements, a port 101, a receiving unit 102, a transmitting unit 103, and a setting unit 104. The functions of the receiving unit 102, the transmitting unit 103, and the setting unit 104 are realized by software. The functions of the receiving unit 102, the transmitting unit 103, and the setting unit 104 may also be referred to as the functions of the transfer device 10. Also, the receiving unit 102, the transmitting unit 103, and the setting unit 104 may be referred to as the respective parts of the transfer device 10.

[0035] The processor 910 is a device that executes a transfer program. The transfer program is a program that realizes the functions of the transfer device 10. The processor 910 is an IC that performs arithmetic processing. Specific examples of the processor 910 are a CPU, a DSP, and a GPU. IC is an abbreviation for Integrated Circuit. CPU is an abbreviation for Central Processing Unit. DSP is an abbreviation for Digital Signal Processor. GPU is an abbreviation for Graphics Processing Unit.

[0036] The memory 921 is a storage device that temporarily stores data. Specific examples of the memory 921 are SRAM or DRAM. SRAM is an abbreviation for Static Random Access Memory. DRAM is an abbreviation for Dynamic Random Access Memory. The auxiliary storage device 922 is a storage device for storing data. A specific example of the auxiliary storage device 922 is an HDD. Also, the auxiliary storage device 922 may be a portable storage medium such as an SD (registered trademark) memory card, a CF, a NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, or a DVD. Note that HDD is an abbreviation for Hard Disk Drive. SD (registered trademark) is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash (registered trademark). DVD is an abbreviation for Digital Versatile Disk.

[0037] The input / output interface 930 is an interface for connecting an input / output device. As a specific example, the input / output interface 930 is a port for USB or HDMI (registered trademark). USB is an abbreviation for Universal Serial Bus. HDMI (registered trademark) is an abbreviation for High-Definition Multimedia Interface.

[0038] The communication interface 950 is an interface for communicating with an external device. As a specific example, the communication interface 950 is a port for Ethernet (registered trademark) or a device for performing wireless communication. The communication interface 950 is also referred to as data communication hardware. The port 101 is realized by the communication interface 950.

[0039] The transfer program is executed in the transfer device 10. The transfer program is loaded into the processor 910 and executed by the processor 910. In the memory 921, not only the transfer program but also the OS is stored. The OS is an abbreviation for Operating System. The processor 910 executes the transfer program while executing the OS. The transfer program and the OS may be stored in the auxiliary storage device 922. The transfer program and the OS stored in the auxiliary storage device 922 are loaded into the memory 921 and executed by the processor 910. Note that part or all of the transfer program may be incorporated into the OS.

[0040] The transfer device 10 may include a plurality of processors that replace the processor 910. These plurality of processors share the execution of the transfer program. Each processor is a device that executes the transfer program in the same manner as the processor 910.

[0041] The data, information, signal values, and variable values used, processed, or output by the transfer program are stored in the memory 921, the auxiliary storage device 922, or the registers or cache memory within the processor 910.

[0042] The "part" of each part of the transfer device 10 may be read as "circuit", "step", "procedure", "process", or "circuitry". The transfer program causes the computer to execute each process obtained by reading the "part" of each part of the transfer device 10 as "process". The "process" of each process of the transfer device 10 may be read as "program", "program product", "computer-readable storage medium storing a program", or "computer-readable recording medium recording a program". Also, the transfer method is a method performed by the transfer device 10 executing the transfer program. The transfer program may be provided stored in a computer-readable recording medium. Also, the transfer program may be provided as a program product.

[0043] <Realized by Hardware> FIG. 8 is a diagram showing another example of the hardware configuration of the transfer device 10 according to the present embodiment. In the present embodiment, the functions of each part of the transfer device 10 are realized by software. As a modification, the functions of each part of the transfer device 10 may be realized by hardware. Specifically, the transfer device 10 includes an electronic circuit 909 instead of the processor 910.

[0044] The electronic circuit 909 is a dedicated electronic circuit that realizes the functions of each part of the transfer device 10. Specifically, the electronic circuit 909 is a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, a logic IC, a GA, an ASIC, or an FPGA. GA is an abbreviation for Gate Array. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array.

[0045] The functions of each part of the transfer device 10 may be realized by one electronic circuit or may be distributed and realized by a plurality of electronic circuits.

[0046] As another modification, some of the functions of each part of the transfer device 10 may be realized by an electronic circuit, and the remaining functions may be realized by software. Also, some or all of the functions of each part of the transfer device 10 may be realized by firmware.

[0047] Each of the processor and the electronic circuit is also called a processing circuit. That is, the functions of each part of the transfer device 10 are realized by the processing circuit.

[0048] ***Explanation of the Effects of the Present Embodiment*** In the transfer device according to this embodiment, each frame is distributed to the corresponding reception queue before multiplexing the received frames in the transfer device. Then, by making the received frames wait in the queue according to the gate control setting which is the schedule transfer setting, it is possible to absorb the transmission timing error of devices such as terminals and avoid the failure of the schedule transfer after multiplexing.

[0049] Therefore, according to the transfer device according to this embodiment, by absorbing the transmission timing error of devices such as terminals, the required accuracy of the transmission timing synchronization of the devices can be relaxed, contributing to the reduction of device costs.

[0050] Embodiment 2. In this embodiment, mainly, the points different from Embodiment 1 and the points added to Embodiment 1 will be described. In this embodiment, the components having the same functions as those in Embodiment 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0051] ***Description of Configuration*** FIG. 9 is a diagram showing a functional configuration example of the transfer device 10 according to this embodiment. In this embodiment, a configuration in which a terminal is connected to a specific port of the transfer device 10 will be described. For example, a configuration in which a terminal is connected to the electrical port of the transfer device 10 and another transfer device 10 is connected to the optical port of the transfer device 10.

[0052] Thus, when the port to which the terminal is connected is limited, as described in Embodiment 1, the reception gate control process may be performed only at the branch port to which the terminal is connected. As shown in FIG. 9, it is sufficient to have a distribution unit 122, a reception queue 123, and a reception gate control unit 124 only at a specific port. In the case of FIG. 9, port 101 corresponds to the branch port and port 105 corresponds to the trunk port. The operations of each part of the transfer device 10 are the same as those in Embodiment 1.

[0053] ***Description of the Effects of this Embodiment*** In the transfer device according to this embodiment, in addition to the effects of Embodiment 1, the equipment cost of the transfer device can be further reduced.

[0054] In the above Embodiments 1 and 2, each part of the transfer device has been described as an independent functional block. However, the configuration of the transfer device does not have to be the same as that in the above-described embodiments. As long as the functional blocks of the transfer device can realize the functions described in the above-described embodiments, any configuration may be used. Further, the transfer device may be not a single device but a system composed of a plurality of devices. Also, in Embodiments 1 and 2, a plurality of parts may be combined and implemented. Alternatively, one part among these embodiments may be implemented. In addition, these embodiments may be combined and implemented in any manner, either as a whole or partially. That is, in Embodiments 1 and 2, free combinations of the respective embodiments, or modifications of any constituent elements of the respective embodiments, or omissions of any constituent elements in the respective embodiments are possible.

[0055] Note that the above-described embodiments are essentially preferred examples and are not intended to limit the scope of the present disclosure, the scope of the applications of the present disclosure, and the scope of the uses of the present disclosure. The above-described embodiments can be variously modified as necessary. For example, the procedures described using a flowchart or a sequence diagram may be appropriately changed.

Description of Reference Numerals

[0056] 10 Transfer device, 101 Port, 102 Receiver, 103 Transmitter, 104 Setting unit, 121 Frame identification unit, 122 Demultiplexing unit, 123 Receive queue, 124 Receive gate control unit, 125 Multiplexing unit, 103 Transmitter, 131 Separation unit, 132 Transmit queue, 133 Transmit gate control unit, 500 Transfer system, 909 Electronic circuit, 910 Processor, 921 Memory, 922 Auxiliary storage device, 930 Input / output interface, 950 Communication interface.

Claims

1. A frame identifier unit that assigns a corresponding identifier to a received frame based on the content of the received frame; A distribution unit that stores the received frame in a reception queue corresponding to the identifier assigned to the received frame; A gate control setting unit that sets the open / close information of the reception queue, and sets a gate control setting for waiting for a received frame that causes a cycle violation in the communication cycle in the reception queue; A reception gate control unit that executes a reception gate control process for reading a received frame from the reception queue based on the gate control setting; comprising The distribution unit When the transfer device has a reception queue corresponding to the identifier assigned to the received frame, stores the received frame in the corresponding reception queue, and when the transfer device does not have the corresponding queue, transmits the received frame to the reception gate control unit.

2. The setting unit sets setting information for determining an identifier, The frame identifier unit assigns a corresponding identifier by pattern matching between an attribute including a reception port number, header information, payload information, and error information of the received frame and the setting information. The transfer device according to claim 1.

3. The reception gate control unit As the reception gate control process, selects either an operation of queuing or discarding based on the difference between the gate control setting and the arrival timing of the received frame. The transfer device according to claim 1 or claim 2.

4. The setting unit For each port that receives a received frame, it is possible to set either a branch port or a trunk port type. The port set as the branch port executes the reception gate control process, and the port set as the trunk port does not execute the reception gate control process but executes normal transfer control. The transfer device according to claim 1 or claim 2.

5. A computer assigns a corresponding identifier to a received frame based on the content of the received frame, A computer performs a distribution step of storing the received frame in a reception queue corresponding to the identifier assigned to the received frame, A computer sets gate control settings for setting the open / close information of the reception queue, and sets gate control settings for waiting for a received frame that causes a cycle violation in the communication cycle in the reception queue, A computer executes a reception gate control process of reading a received frame from the reception queue based on the gate control settings, In the distribution step, when the transfer device has a reception queue corresponding to the identifier assigned to the received frame, the computer stores the received frame in the corresponding reception queue, and when the transfer device does not have the corresponding queue, the computer transmits the received frame to the reception gate control process. Transfer method.

6. A frame identification process of assigning a corresponding identifier to a received frame based on the content of the received frame, A distribution process of storing the received frame in a reception queue corresponding to the identifier assigned to the received frame, A setting process for setting gate control settings for setting the open / close information of the reception queue, and setting gate control settings for waiting for a received frame that causes a cycle violation in the communication cycle in the reception queue, A reception gate control process of reading a received frame from the reception queue based on the gate control settings is executed by a computer, The distribution process is A transfer program that stores a received frame in a corresponding receive queue if the transfer device has a receive queue corresponding to the identifier assigned to the received frame, and transmits the received frame to the receive gate control process if the transfer device does not have the corresponding queue.

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