CONTROL DEVICE, CONTROL METHOD, CONTROL PROGRAM, AND SIGNAL TRANSFER CONTROL SYSTEM

Abstract

In the present invention, a signal transfer device receives a periodic signal that is transmitted periodically, and transfers the periodic signal in a reserved window. A control device controlling the signal transfer device is provided with a storage device for storing reference information indicating the transmission quantity and transmission period of the periodic signal, of each of a plurality of flows, received by the signal transfer device. The control device is further provided with a processor for executing window setting processing on the basis of the reference information. In the window setting processing, the control device sets, on the basis of the reference information, a schedule for a plurality of windows corresponding respectively to the plurality of flows in the signal transfer device, and instructs the signal transfer device to reserve the plurality of windows in accordance with the schedule.

Description

[Technical field]

[0001] The present disclosure relates to a technique for controlling a signal forwarding device that forwards a periodic signal in a reserved window. [Background technology]

[0002] Non-Patent Documents 1 and 2 disclose TSN (Time-Sensitive Networking) that ensures real-time performance.

[0003] TAS (Time Aware Shaper) is one technology for realizing a low-latency network. TAS achieves low latency, particularly for priority signals that are periodically transmitted from a transmitting device. Specifically, in a signal forwarding device such as a switch in a network, a window (forwarding period, time slot) for forwarding a priority signal is reserved (secured) in advance. In the reserved window, the gate of the queue for the priority signal opens and the priority signal is forwarded, while the gate of the queue for other signals is closed and the other signals are made to wait without being forwarded. As a result, the queuing delay of the priority signal is suppressed. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "IEEE Standard for Local and metropolitan area networks- Time-Sensitive Networking for Fronthaul," IEEE Std 802.1CM, May 7, 2018 [Non-Patent Document 2] J. Farkas, "Introduction to IEEE802.1 Focus on the Time-Sensitive Networking Task Group," May15, 2017 (https: / / www.ieee802.org / 1 / files / public / docs2017 / tsn-farkas-intro-0517-v01.pdf) Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, TAS handles signals that are transmitted periodically (hereinafter referred to as "periodic signals"). Here, consider the case where a signal forwarding device receives periodic signals of multiple flows. In the signal forwarding device, multiple windows for each of the multiple flows are reserved in advance. In this case, a technology that can flexibly reserve (set) multiple windows for each of the multiple flows is desired.

[0006] For example, if the transmission periods of periodic signals are different among multiple flows, multiple windows for the multiple flows may overlap at the same time. If window overlap occurs, only the periodic signal of one flow is transferred during the overlapping period, and the periodic signals of the other flows are not transferred. As a result, at least a part of the periodic signal remains queued until the next window. Therefore, jitter equivalent to the window period occurs.

[0007] One object of the present disclosure is to provide a technology for controlling a signal forwarding device that forwards a periodic signal in a reserved window, the technology being capable of flexibly reserving multiple windows for each of multiple flows. [Means for solving the problem]

[0008] A first aspect relates to a control device for controlling a signal forwarding device. The signal forwarding device receives a periodic signal that is periodically transmitted, and forwards the periodic signal in a reserved window. The control device includes: A storage device that stores reference information indicating a transmission amount and a transmission period of each of a plurality of flows received by the signal forwarding device; a processor that executes a window setting process to set a schedule of a plurality of windows for each of a plurality of flows in the signal forwarding device based on the reference information and instruct the signal forwarding device to reserve the plurality of windows according to the schedule; Equipped with.

[0009] A second aspect relates to a method for controlling a signal forwarding device, the signal forwarding device receiving a periodically transmitted periodic signal and forwarding the periodic signal in a reserved window. The control method is A process of acquiring reference information indicating a transmission amount and a transmission period of each of a plurality of flows received by a signal forwarding device; a window setting process for setting a schedule of a plurality of windows for each of a plurality of flows in the signal forwarding device based on the reference information and instructing the signal forwarding device to reserve the plurality of windows according to the schedule; Includes.

[0010] A third aspect relates to a control program executed by a processor for controlling a signal forwarding device, the signal forwarding device receiving a periodic signal that is periodically transmitted, and forwarding the periodic signal in a reserved window. The control program is A process of acquiring reference information indicating a transmission amount and a transmission period of each of a plurality of periodic signals of a plurality of flows received by a signal forwarding device; a window setting process for setting a schedule of a plurality of windows for each of a plurality of flows in the signal forwarding device based on the reference information and instructing the signal forwarding device to reserve the plurality of windows according to the schedule; The processor executes the following.

[0011] The fourth aspect relates to a signal transfer control system. The signal transfer control system is a signal forwarding device for receiving a periodically transmitted periodic signal and forwarding the periodic signal in a reserved window; A control device for controlling a signal transfer device It is equipped with. The control device includes: A storage device that stores reference information indicating a transmission amount and a transmission period of each of a plurality of flows received by the signal forwarding device; a processor that executes a window setting process to set a schedule of a plurality of windows for each of a plurality of flows in the signal forwarding device based on the reference information and instruct the signal forwarding device to reserve the plurality of windows according to the schedule; Equipped with. Effect of the Invention

[0012] According to the present disclosure, a window setting process is performed based on reference information regarding a periodic signal of each flow received by a signal forwarding device. More specifically, a schedule of multiple windows for each of multiple flows in the signal forwarding device is set based on the reference information. The signal forwarding device is instructed to reserve multiple windows according to the set schedule. This makes it possible to flexibly reserve (set) multiple windows for each of multiple flows in the signal forwarding device. [Brief description of the drawings]

[0013] [Figure 1] 1 is a block diagram illustrating a schematic configuration of a signal transfer control system according to an embodiment of the present disclosure. [Diagram 2] 1 is a block diagram showing a configuration example of a signal transfer device according to an embodiment of the present disclosure. [Diagram 3] 1 is a block diagram showing a configuration example of a control device according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a conceptual diagram for explaining one problem. [Diagram 5] 11A and 11B are conceptual diagrams for explaining an example of a window adjustment process according to an embodiment of the present disclosure. [Figure 6] 11A and 11B are conceptual diagrams for explaining another example of the window adjustment process according to the embodiment of the present disclosure. [Figure 7] 10 is a flowchart illustrating an example of a window setting process according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0015] 1. Signal transfer control system 1-1. Overview 1 is a block diagram showing a schematic configuration of a signal transfer control system 1 according to the present embodiment. The signal transfer control system 1 includes a transmitting device 10, a signal transfer device 20, and a receiving device 30. The transmitting device 10 and the receiving device 30 are connected via at least one signal transfer device 20, thereby forming a communication network. A plurality of signal transfer devices 20 may be interposed between the transmitting device 10 and the receiving device 30.

[0016] The transmitting device 10 transmits a signal to the receiving device 30, generating traffic (flow). The transmitting device 10 is, for example, a user terminal. The signal forwarding device 20 receives the signal transmitted from the transmitting device 10 and forwards the received signal to a device at the next stage. The signal forwarding device 20 is, for example, a switch. The receiving device 30 receives the signal transmitted from the transmitting device 10 and forwarded by the signal forwarding device 20.

[0017] The signals transmitted from the transmitting device 10 include "periodic signals" that are transmitted periodically. The signal forwarding device 20 supports TAS (Time Aware Shaper) that realizes low delay of the periodic signals. Specifically, in the signal forwarding device 20, a window (transfer period, time slot) for forwarding the periodic signal is reserved (secured) in advance. In the reserved window, the gate of the queue for the periodic signal is opened and the periodic signal is forwarded, while the gate of the queue for other signals is closed and the other signals are made to wait without being forwarded. As a result, the queuing delay of the periodic signal is suppressed.

[0018] The signal transfer control system 1 according to the present embodiment further includes a control device 100. The control device 100 is communicably connected to each signal transfer device 20 and configured to be able to control each signal transfer device 20. In particular, the control device 100 is configured to be able to flexibly reserve a window in each signal transfer device 20. In other words, the control device 100 is configured to be able to variably set a window in each signal transfer device 20.

[0019] More specifically, the control device 100 sets a schedule for a window in the signal transfer device 20, and transmits "schedule setting information SKD" to the signal transfer device 20. The schedule setting information SKD indicates a schedule for the set window, and is information that instructs the signal transfer device 20 to reserve (set) the window according to the schedule. The signal transfer device 20 receives the schedule setting information SKD transmitted from the control device 100, and reserves (sets) the window according to the schedule specified by the schedule setting information SKD. That is, the control device 100 flexibly controls the window setting in the signal transfer device 20 by transmitting the schedule setting information SKD to the signal transfer device 20.

[0020] It is also possible that the signal transfer device 20 receives periodic signals for each of a plurality of flows (traffic). In this case, the control device 100 sets a schedule for a plurality of windows for each of a plurality of flows in the signal transfer device 20. Then, the control device 100 transmits schedule setting information SKD indicating the schedule for the plurality of windows that has been set to the signal transfer device 20. The signal transfer device 20 receives the schedule setting information SKD transmitted from the control device 100, and reserves (sets) a plurality of windows for each of a plurality of flows according to the schedule specified by the schedule setting information SKD. In this way, it becomes possible to flexibly reserve (set) a plurality of windows for each of a plurality of flows in the signal transfer device 20.

[0021] 1-2. Example of signal transmission device configuration 2 is a block diagram showing an example of the configuration of a signal transfer device 20 according to this embodiment. The signal transfer device 20 includes a signal distribution unit 21, a buffer unit 22, a time gate unit 23, a signal transfer unit 24, a scheduler unit 25, and an interface unit 26.

[0022] The signal distribution unit 21 receives an input signal input to the signal transfer device 20. The signal distribution unit 21 distributes the input signal for each flow priority and outputs the input signal for each priority to the buffer unit 22. The priority of a flow is defined, for example, by a CoS (Class Of Service) value in the header. The input signal also includes a periodic signal that is periodically transmitted from the transmission device 10. Typically, the periodic signal is a priority signal with a high priority.

[0023] The buffer unit 22 has a different buffer (queue) for each priority of a flow. That is, the buffer unit 22 has a plurality of buffers 22-1 to 22-n provided for each of a plurality of priorities, where n is an integer equal to or greater than 2. An input signal for each flow is stored in a buffer associated with the priority of the flow.

[0024] The time gate unit 23 is provided to control signal transmission for each buffer (priority). More specifically, the time gate unit 23 has a plurality of gates 23-1 to 23-n provided for each of a plurality of priorities. The plurality of gates 23-1 to 23-n are connected to the plurality of buffers 22-1 to 22-n, respectively. When the gate 23-i (i=1 to n) is closed, no signal is output from the buffer 22-i. When the gate 23-i is opened, the signal stored in the buffer 22-i is transmitted to the signal transfer unit 24.

[0025] The signal transfer unit 24 receives a signal from the buffer unit 22 via the time gate unit 23. The signal transfer unit 24 outputs the received signal to the next stage device.

[0026] The scheduler unit 25 controls the signal transfer by the signal transfer device 20 by controlling the opening and closing of each of the gates 23-1 to 23-n of the time gate unit 23. The scheduler unit 25 also supports TAS and reserves windows (transfer periods, time slots) for transferring periodic signals. In the reserved window, the scheduler unit 25 opens only the gate 23-p corresponding to the buffer 22-p in which the periodic signal is stored, and closes the other gates.

[0027] According to this embodiment, the control device 100 may determine a schedule of a window for transferring a periodic signal. In this case, the control device 100 transmits schedule setting information SKD to the signal transfer device 20. The interface unit 26 of the signal transfer device 20 communicates with the control device 100 and receives the schedule setting information SKD from the control device 100. The interface unit 26 transfers the received schedule setting information SKD to the scheduler unit 25. The scheduler unit 25 reserves (sets) a window according to the schedule specified by the schedule setting information SKD.

[0028] 1-3.Example of control device configuration 3 is a block diagram showing a configuration example of the control device 100 according to the present embodiment. The control device 100 includes one or more processors 110 (hereinafter simply referred to as "processors 110"), one or more storage devices 120 (hereinafter simply referred to as "storage devices 120"), and a communication interface 130.

[0029] The processor 110 performs various information processing. For example, the processor 110 includes a CPU (Central Processing Unit). The storage device 120 stores various information required for processing by the processor 110. Examples of the storage device 120 include a volatile memory, a non-volatile memory, a HDD (Hard Disk Drive), and an SSD (Solid State Drive). The communication interface 130 communicates with each signal transfer device 20.

[0030] The control program PROG is a computer program executed by the processor 110. The processor 110 executes the control program PROG to realize the functions of the processor 110 (control device 100). The control program PROG is stored in the storage device 120. The control program PROG may be recorded in a computer-readable recording medium. The control program PROG may be provided to the control device 100 via a network.

[0031] The processor 110 may be implemented using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA).

[0032] The reference information REF indicates the transmission amount, transmission period, transmission phase, initial transmission time, etc. of the periodic signal of each flow received by the signal forwarding device 20. For example, the reference information REF is collected from the transmitting device 10 or the signal forwarding device 20 that handles the periodic signal of each flow. As another example, the reference information REF may be provided in advance to the control device 100 by a network administrator. The processor 110 acquires the reference information REF. The acquired reference information REF is stored in the storage device 120.

[0033] The processor 110 executes a "window setting process" based on the reference information REF. More specifically, the processor 110 sets a schedule of a window for each flow in the signal forwarding device 20 based on the transmission amount, transmission period, etc. of the periodic signal of each flow indicated by the reference information REF. When the signal forwarding device 20 receives periodic signals of multiple flows, the processor 110 sets a schedule of multiple windows for each of the multiple flows. The priorities of the multiple flows may be different. Then, the processor 110 generates schedule setting information SKD that reflects the schedule setting result. More specifically, the schedule setting information SKD indicates the schedule of the set window, and is information that instructs the signal forwarding device 20 to reserve (set) the window according to the schedule. The schedule setting information SKD is stored in the storage device 120. The processor 110 transmits the generated schedule setting information SKD to the signal forwarding device 20 via the communication interface 130.

[0034] 1-4.Effects As described above, according to this embodiment, the control device 100 executes a window setting process based on reference information REF regarding the periodic signal of each flow received by the signal transfer device 20. More specifically, the control device 100 sets a schedule of multiple windows for each of the multiple flows in the signal transfer device 20 based on the reference information REF. Then, the control device 100 instructs the signal transfer device 20 to reserve multiple windows according to the set schedule. This makes it possible to flexibly reserve (set) multiple windows for each of the multiple flows in the signal transfer device 20.

[0035] 2. Window setting processing example 2-1. Overview As an example, consider below a case where the transmission period of a periodic signal differs among a plurality of flows.

[0036] When the transmission periods of the periodic signals are different among the multiple flows, there is a possibility that the multiple windows for the multiple flows may overlap at the same time. When the windows overlap, only the periodic signal of one flow is transferred during the overlapping period, and the periodic signals of the other flows are not transferred. As a result, at least a part of the periodic signal remains queued until the next window. Therefore, jitter of the window period occurs.

[0037] Fig. 4 is a conceptual diagram for explaining the above problem. Here, two types of flows are considered: a first flow A and a second flow B. The priority of the first flow A is assumed to be higher than the priority of the second flow B. The periodic signals of the first flow A and the second flow B are transferred in the order of signal transfer devices 20-1, 20-2, and 20-3.

[0038] Consider the signal forwarding device 20-1 as an example. The first window WA is a window set for forwarding a periodic signal of the first flow A. The first transmission period F A is the transmission period of the periodic signal of the first flow A. The first transmission time LA is the time required to transmit the amount of the periodic signal of the first flow A per transmission. A is the initial transmission time of the periodic signal of the first flow A in the signal transfer device 20-1. The default setting of the first window WA in the signal transfer device 20-1 is as follows. The numbers in parentheses indicate the identification numbers of the cycles.

[0039] <Default settings for the first window WA> WA(0)=t0 A ~t0 A +L A WA(1)=t0 A +F A ~t0 A +F A +L A WA(2)=t0 A +2×F A ~t0 A +2×F A +L A ...

[0040] Similarly, the second window WB is a window set for transmitting a periodic signal of the second flow B. The second transmission period F B is the transmission period of the periodic signal of the second flow B. The second transmission time L B is the time required to transmit the amount of the periodic signal of the second flow B per transmission. B is the initial transmission time of the periodic signal of the second flow B in the signal forwarding device 20-1. The default setting of the second window WB in the signal forwarding device 20-1 is as follows.

[0041] <Second window WB default settings> WB(0)=t0 B ~t0 B +L B WB(1)=t0 B +F B ~t0 B +FB +L B WB(2)=t0 B +2×F B ~t0 B +2×F B +L B ...

[0042] The default setting of the first window WA in the signal transfer devices 20-2 and 20-3 is shifted by the transmission delay from the default setting of the first window WA in the signal transfer device 20-1. Similarly, the default setting of the second window WB in the signal transfer devices 20-2 and 20-3 is shifted by the transmission delay from the default setting of the second window WB in the signal transfer device 20-1.

[0043] 1st transmission cycle F A and the second transmission period F B are different from each other. Therefore, there is a possibility that the first window WA(j) in a certain cycle j and the second window WB(k) in a certain cycle k may overlap. In the example shown in FIG. 4, the latter half of the first window WA(j) in a certain cycle j overlaps with the first half of the second window WB(k) in a certain cycle k. During the overlapping period, only the periodic signal of the first flow A is transferred, and the periodic signal of the second flow B is not transferred. As a result, a part of the periodic signal of the second flow B in the cycle k remains queued until the next second window WB(k+1). As a result, the second transmission cycle F for the periodic signal of the second flow B is delayed. B This results in minute jitter.

[0044] In order to suppress the occurrence of such jitter, the control device 100 (processor 110) according to this embodiment executes a "window adjustment process" as appropriate.

[0045] FIG. 5 is a conceptual diagram for explaining the window adjustment process in the situation shown in FIG. 4. The processor 110 moves (shifts) at least one of the first window WA(j) and the second window WB(k) so that the first window WA(j) and the second window WB(k) do not overlap. In the example shown in FIG. 5, the processor 110 moves the second window WB(k) for the second flow B, which has a relatively low priority, to the rear of the first window WA(j). For example, if the default overlap time of the first window WA(j) and the second window WB(k) is Δt, the processor 110 moves (shifts) the second window WB(k) backward by the overlap time Δt from the default setting. This eliminates the overlap between the first window WA(j) and the second window WB(k). As a result, jitter related to the transfer of the periodic signal of the second flow B is suppressed.

[0046] 6 is a conceptual diagram for explaining another example of the window adjustment process. In the default setting, the latter half of the second window WB(k) in a certain cycle k overlaps with the first half of the first window WA(j) in a certain cycle j. In this case as well, the processor 110 moves the second window WB(k) for the second flow B, which has a relatively low priority, to the rear of the first window WA(j). This eliminates the overlap between the first window WA(j) and the second window WB(k), and suppresses jitter.

[0047] In general, the process is as follows. In the window setting process, the processor 110 obtains default settings of multiple windows for each of the multiple flows based on the reference information REF. If the default settings of the multiple windows overlap, the processor 110 executes a window adjustment process to adjust at least a part of the multiple windows so as to eliminate the overlap. Then, the processor 110 transmits schedule setting information SKD reflecting the adjusted window settings to each signal transfer device 20. That is, the processor 110 sets multiple windows for each of the multiple flows so as not to overlap with each other by appropriately executing the window adjustment process during the window setting process. This suppresses jitter related to the transfer of periodic signals.

[0048] 2-2. Processing flow example FIG. 7 is a flowchart showing an example of a window setting process according to the present embodiment.

[0049] In step S100, the processor 110 obtains the "window setting priority" of the multiple flows. The window setting priority is a priority for reserving a window. Typically, the priority of each of the multiple flows is used as it is as the window setting priority. For example, in the example shown in Figs. 4 to 6 above, the window setting priority of the first flow A is higher than the window setting priority of the second flow B. In other words, the window setting priority of the second flow B is lower than the window setting priority of the first flow A.

[0050] In step S110, the processor 110 sets the flow with the highest window setting priority (e.g., the first flow A) as the target flow. Then, the processor 110 sets (reserves) a window for the target flow based on the reference information REF. The window here is a default window.

[0051] In step S120, processor 110 determines whether or not there is a flow with a lower window setting priority. If there is no flow with a lower window setting priority (step S120; No), the processing in the current cycle ends. On the other hand, if there is a flow with a lower window setting priority (step S120; Yes), processor 110 sets the flow as a target flow. Then, the processing proceeds to step S130.

[0052] In step S130, the processor 110 provisionally sets a window for the target flow (for example, the second flow B) based on the reference information REF. The window here is a default window.

[0053] In the following step S140, processor 110 determines whether or not the window tentatively set in step S130 overlaps with a window of a higher priority that has already been set. If the tentatively set window overlaps with a window of a higher priority that has already been set (step S140; Yes), the process proceeds to step S150. Otherwise (step S140; No), the process returns to step S120.

[0054] In step S150, processor 110 executes the window adjustment process described above (see Figs. 5 and 6). That is, processor 110 moves the provisionally set window behind the window with the higher priority so as to eliminate the overlap. Then, the process returns to step S120.

[0055] 7, processor 110 allocates windows for flows with higher window setting priority with higher priority. If overlapping of windows occurs, processor 110 performs window adjustment processing to eliminate the overlap. This makes it possible to set multiple windows for multiple flows so that they do not overlap with each other, thereby suppressing jitter.

[0056] 2-3.Modifications The processor 110 may repeatedly execute the window setting process. For example, the processor 110 may execute the window setting process periodically.

[0057] The processor 110 may change the settings of the window setting priority for multiple flows every time the window setting process is performed. For example, in one window setting process, the processor 110 sets the window setting priority of the first flow A higher than the window setting priority of the second flow B. Then, in the next window setting process, the processor 110 sets the window setting priority of the second flow B higher than the window setting priority of the first flow A.

[0058] The processor 110 may execute the window setting process based on a preset allowable jitter. For example, when an allowable jitter is set for each of a plurality of flows, the processor 110 sets a higher window setting priority for a flow with a smaller (stricter) allowable jitter. For example, when the allowable jitter for the first flow A is 100 μs and the allowable jitter for the second flow B is 200 μs, the window setting priority for the first flow A is set higher than the window setting priority for the second flow B. [Explanation of symbols]

[0059] 1...signal transfer control system, 10...transmitting device, 20...signal transfer device, 21...signal distribution section, 22...buffer section, 22-1 to 22-n...buffers, 23...time gate section, 23-1 to 23-n...gates, 24...signal transfer section, 25...scheduler section, 26...interface section, 30...receiving device, 100...control device, 110...processor, 120...storage device, 130...communication interface, PROG...control program, REF...reference information, SKD...schedule setting information

Claims

1. A control device for controlling a signal forwarding device that receives a periodically transmitted periodic signal and forwards the periodic signal in a reserved window, a storage device that stores reference information indicating a transmission amount and a transmission period of the periodic signal for each of a plurality of flows received by the signal forwarding device; a processor that executes a window setting process to set a schedule of a plurality of windows for each of the plurality of flows in the signal forwarding device based on the reference information and to instruct the signal forwarding device to reserve the plurality of windows according to the schedule; Equipped with the transmission period of the periodic signal differs among the plurality of flows; In the window setting process, the processor obtains window setting priorities of the plurality of flows, and reserves the window for a flow having a higher window setting priority with higher priority; the plurality of flows includes a first flow and a second flow having a window setting priority lower than that of the first flow; a first window is the window for forwarding the periodic signal of the first flow; a second window is the window for forwarding the periodic signal of the second flow; In the window setting process, the processor obtaining default settings for the plurality of windows for each of the plurality of flows based on the reference information; reserving the default setting as a window for a flow among the plurality of flows that has the highest window setting priority; After reserving the first window, temporarily setting the second window to the default settings; If the provisionally set second window overlaps with the first window, the second window is moved behind the first window so that the overlap is eliminated. Control device.

2. The control device according to claim 1 , The processor repeatedly executes the window setting process, and changes the window setting priority settings for the plurality of flows every time the window setting process is executed. Control device.

3. A method for controlling a signal forwarding device that receives a periodically transmitted periodic signal and forwards the periodic signal in a reserved window, comprising: A process of acquiring reference information indicating a transmission amount and a transmission period of the periodic signal for each of a plurality of flows received by the signal transfer device; a window setting process for setting a schedule of a plurality of windows for each of the plurality of flows in the signal transfer device based on the reference information, and instructing the signal transfer device to reserve the plurality of windows according to the schedule; Including, the transmission period of the periodic signal differs among the plurality of flows; the window setting process includes obtaining window setting priorities of the plurality of flows, and reserving the window for a flow having a higher window setting priority with higher priority; the plurality of flows includes a first flow and a second flow having a window setting priority lower than that of the first flow; a first window is the window for forwarding the periodic signal of the first flow; a second window is the window for forwarding the periodic signal of the second flow; The window setting process includes: obtaining default settings for the plurality of windows for each of the plurality of flows based on the reference information; reserving the default setting as a window for a flow among the plurality of flows that has the highest window setting priority; provisionally setting the second window to the default settings after reserving the first window; If the provisionally set second window overlaps with the first window, moving the second window to the rear of the first window so as to eliminate the overlap. Includes Control methods.

4. A control program executed by a processor to control a signal forwarding device that receives a periodically transmitted periodic signal and forwards the periodic signal in a reserved window, A process of acquiring reference information indicating a transmission amount and a transmission period of the periodic signal for each of a plurality of flows received by the signal transfer device; a window setting process for setting a schedule of a plurality of windows for each of the plurality of flows in the signal transfer device based on the reference information, and instructing the signal transfer device to reserve the plurality of windows according to the schedule; causing the processor to execute the transmission period of the periodic signal differs among the plurality of flows; the window setting process includes obtaining window setting priorities of the plurality of flows, and reserving the window for a flow having a higher window setting priority with higher priority; the plurality of flows includes a first flow and a second flow having a window setting priority lower than that of the first flow; a first window is the window for forwarding the periodic signal of the first flow; a second window is the window for forwarding the periodic signal of the second flow; The window setting process includes: obtaining default settings for the plurality of windows for each of the plurality of flows based on the reference information; reserving the default setting as a window for a flow among the plurality of flows that has the highest window setting priority; provisionally setting the second window to the default settings after reserving the first window; If the provisionally set second window overlaps with the first window, moving the second window to the rear of the first window so as to eliminate the overlap. Includes Control program.

5. a signal forwarding device for receiving a periodically transmitted periodic signal and forwarding the periodic signal in a reserved window; A control device for controlling the signal transfer device With The control device includes: a storage device that stores reference information indicating a transmission amount and a transmission period of the periodic signal for each of a plurality of flows received by the signal forwarding device; a processor that executes a window setting process to set a schedule of a plurality of windows for each of the plurality of flows in the signal forwarding device based on the reference information and to instruct the signal forwarding device to reserve the plurality of windows according to the schedule; Equipped with the transmission period of the periodic signal differs among the plurality of flows; In the window setting process, the processor obtains window setting priorities of the plurality of flows, and reserves the window for a flow having a higher window setting priority with higher priority; the plurality of flows includes a first flow and a second flow having a window setting priority lower than that of the first flow; a first window is the window for forwarding the periodic signal of the first flow; a second window is the window for forwarding the periodic signal of the second flow; In the window setting process, the processor obtaining default settings for the plurality of windows for each of the plurality of flows based on the reference information; reserving the default setting as a window for a flow among the plurality of flows that has the highest window setting priority; After reserving the first window, temporarily setting the second window to the default settings; If the provisionally set second window overlaps with the first window, the second window is moved behind the first window so that the overlap is eliminated. Signal transfer control system.

Images