Communication system, control device, and program

Abstract

A communication system (100) according to the present disclosure comprises a control device (5), the control device (5) including: a period determination unit (504) that determines whether a given period is a divisor of the least common multiple (h_prd) of a frame transmission period in each of a plurality of flows; and a GCL calculation unit (505) that sets a time slot to a GCL in a first period (prd1) if it is determined that the first period (prd1) is a divisor of the least common multiple, and sets a time slot for allowing communication devices (3k) different from a final communication device to respectively transmit additional frames to the GCL in a second period (prd2), which is a divisor of the least common multiple (h_prd), if it is determined that the first period (prd1) is not a divisor of the least common multiple (h_prd).

Description

[Technical Field]

[0001] The present disclosure relates to a communication system, a control device, and a program. [Background technology]

[0002] BACKGROUND ART In a communication system that uses a TAS (Time Aware Shaper) technique for communication, a technique is known that guarantees delays using a gate control list (GCL) that indicates the schedule of a communication device (see, for example, Non-Patent Document 1).

[0003] Generally, the GCL has a length that is the least common multiple of the periods in which frames of multiple flows are transmitted. Since a communication device repeats frame transmission according to the GCL, it can transmit frames of multiple flows using deterministic periodic communication. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Yuhei Kawakami, 5 others, "Applying Time-aware Shaper Considering User Identifier to Service Provider Network", IEEE 19th Annual Consumer Communications & Networking Conference, 2022 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when adding a time slot for transmitting an additional frame of an additional flow to a GCL designed as described above, it may not be possible to represent the repetition of the transmission of the additional frame while maintaining the length of the existing GCL. Specifically, if the period for transmitting the additional frame is not a divisor of the least common multiple of the periods for transmitting frames in the multiple flows indicated in the existing GCL, it may not be possible to represent the repetition of the transmission of the additional frame while maintaining the length of the existing GCL. In such a case, it is necessary to design a GCL whose length is the least common multiple of the periods for transmitting frames in the multiple flows indicated in the existing GCL and the periods for transmitting the additional frame.

[0006] The GCL designed in this way is longer than the existing GCL, which increases the complexity of communication control, including scheduling. Furthermore, changing the length of the GCL requires stopping the communication system in operation, which in turn requires interrupting the services provided by the communication system.

[0007] In view of the above circumstances, the purpose of the present disclosure is to provide a communication system, a control device, and a program that can prevent the complexity of communication control from increasing when a new flow is added, and can avoid service interruptions. [Means for solving the problem]

[0008] In order to solve the above problem, a communication system according to the present disclosure is a communication system including: a transmitting terminal that transmits delay-guaranteed frames; a plurality of communication devices that sequentially forward the frames; a receiving terminal that receives the frames forwarded by the plurality of communication devices; and a control device that controls the plurality of communication devices, wherein the control device includes a gate control list storage unit that stores a gate control list indicating a schedule for each of the communication devices to transmit frames in a plurality of flows; a user setting receiving unit that receives an additional schedule for the transmitting terminal to transmit additional frames in an additional flow different from the plurality of flows; and a first period that is a transmission period for the additional frames indicated in the additional schedule, the first period being a transmission period for the frames in each of the plurality of flows. a gate control list calculation unit that, if it is determined that the first period is a divisor of the least common multiple, sets the time slots for the plurality of communication devices to transmit the additional frames at the first period in the gate control list of each of the plurality of communication devices; and, if it is determined that the first period is not a divisor of the least common multiple, sets the time slots for each of the plurality of communication devices, other than the last communication device that transmits the additional frames directly to the receiving terminal, at a second period that is shorter than the first period and is a divisor of the least common multiple; and a communication device transmission unit that transmits the gate control list in which the time slots are set to the communication device.

[0009] In order to solve the above problem, a control device according to the present disclosure is a control device that controls a plurality of communication devices that transfer frames from a transmitting terminal to a receiving terminal, and includes a gate control list storage unit that stores a gate control list indicating a schedule for each of the communication devices to transmit frames in a plurality of flows, a user setting receiving unit that receives an additional schedule for the transmitting terminal to transmit additional frames in an additional flow that is different from the plurality of flows, a period determination unit that determines whether a first period that is a transmission period of the additional frames indicated in the additional schedule is a divisor of the least common multiple of the transmission periods of frames in the plurality of flows, and a period determination unit that determines whether the first period is a divisor of the least common multiple of the transmission periods of frames in the plurality of flows. a gate control list calculation unit that, if it is determined that the first period is a divisor of the least common multiple, sets the time slots for the multiple communication devices to transmit the additional frames at the first period in the respective gate control lists; and, if it is determined that the first period is not a divisor of the least common multiple, sets the time slots for each of the multiple communication devices, other than the last communication device that transmits the additional frames directly to the receiving terminal, at a second period that is shorter than the first period and is a divisor of the least common multiple, in the gate control list; and a communication device transmission unit that transmits the gate control list in which the time slots are set to the communication devices.

[0010] In order to solve the above problem, a program according to the present disclosure causes a computer to operate as the above-described control device. [Effects of the Invention]

[0011] According to the communication system, control device, and program disclosed herein, it is possible to suppress an increase in the complexity of communication control and avoid interruptions in service. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a communication system according to a first embodiment. [Figure 2]FIG. 2 is a diagram illustrating an example of a control device illustrated in FIG. [Figure 3] FIG. 1 is a schematic diagram illustrating a queue and a gate. [Figure 4] FIG. 1 is a schematic diagram illustrating an example of a GCL. [Figure 5] 4 is a diagram illustrating an example of timing at which frames are transmitted according to a GCL in which time slots are set by a control device according to the first embodiment. FIG. [Figure 6] 5 is a flowchart showing an example of the operation of the control device according to the first embodiment. [Figure 7] 10 is a diagram illustrating an example of timing at which frames are transmitted according to a GCL in which time slots are set by a control device according to a second embodiment. FIG. [Figure 8] 10 is a flowchart showing an example of the operation of the control device according to the second embodiment. [Figure 9] FIG. 2 is a hardware block diagram of a control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] <<First embodiment>> The overall configuration of the first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of a communication system 100 according to the first embodiment.

[0014] The communication system 100 comprises a transmitting terminal (Talker) 1, a receiving terminal (Listener) 2, a plurality of communication devices 3k (k=an integer from 1 to n, n is an integer equal to or greater than 2 (in the example of FIG. 1, n=3)), a user management device 4, and a control device 5. In the communication system 100, delay guaranteed communication (ST (Scheduled Traffic) communication) is performed in which the frame transmission timing and transmission interval are controlled. In ST communication, the communication device 3k controls transfer in a time-division manner using TAS, thereby controlling delay and jitter.

[0015] Talker 1 transmits frames with guaranteed delay. Specifically, Talker 1 transmits frames to Listener 2 via multiple communication devices 3k. Furthermore, when an additional schedule for transmitting frames (additional frames) by a new flow (additional flow) is added, Talker 1 transmits the additional schedule to the user management device 4.

[0016] Listener 2 receives frames forwarded by multiple communication devices 3k. Specifically, Listener 2 receives frames sent by Talker 1 and forwarded by communication device 3k.

[0017] The communication device 3k sequentially forwards frames transmitted from Talker1 to Listener2. Specifically, the communication device 3k receives frames from other devices and transmits frames to other devices. The communication device 3k is a communication network device, and may be, for example, a switch. In ST communication, the communication device 3k performs time-division transfer control using TAS.

[0018] In the following explanation, communication device 3k forwards data in ascending order of k. That is, a frame transmitted from Talker1 is first received by communication device 31, and then forwarded to communication devices 31, 32, ..., 3(n-1), and 3n in that order. Communication device 3n also transmits frames directly to Listener2. In the example shown in FIG. 1, communication device 31 receives a frame from Talker1 and transmits the frame to communication device 32. Communication device 32 also receives a frame from communication device 31 and transmits the frame to communication device 33. Communication device 33 also receives a frame from communication device 32 and transmits the frame to Listener2.

[0019] The user management device 4 manages the settings of Talker 1 and Listener 2. Specifically, the user management device 4 manages the schedule by which Talker 1 transmits frames via each of multiple flows. Furthermore, when an additional schedule is added for Talker 1 to transmit an additional frame via an additional flow, the user management device 4 receives the additional schedule. The user management device 4 is, for example, a Centralized User Configuration (CUC). Note that the communication system 100 does not necessarily have to include the user management device 4. In such a configuration, the control device 5 included in the communication system 100 can send and receive various information to and from devices having functions equivalent to those of the user management device 4.

[0020] <Control device configuration> The control device 5 controls a plurality of communication devices 3k. As shown in Fig. 2, the control device 5 includes a CUC receiving port (user-configured receiving port) 501, a CUC port receiving unit (user-configured receiving unit) 502, a GCL storage unit (gate control list storage unit) 503, a periodicity determining unit 504, a GCL calculation unit (gate control list calculation unit) 505, a CUC transmitting communication port (user-configured transmitting port) 506, a CUC port transmitting unit (user-configured transmitting unit) 507, a TSN-SW transmitting port (communication device transmitting port) 508, and a TSN-SW port transmitting unit (communication device transmitting unit) 509. The control device 5 is, for example, a Central Network Controller (CUC).

[0021] The CUC receiving port 501, the CUC transmitting port 506, and the TSN-SW transmitting port 508 are configured by communication interfaces. The CUC port receiving unit 502, the periodicity determining unit 504, the GCL calculating unit 505, the CUC port transmitting unit 507, and the TSN-SW port transmitting unit 509 are configured by a controller. The controller may be configured by dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), or may be configured by a processor, or may include both. The GCL storage unit 503 is configured by memory. The memory may be an HDD (Hard Disk Drive), an SSD (Solid State Drive), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a ROM (Read Only Memory), a RAM (Random Access Memory), or the like.

[0022] The CUC receiving port 501 is a communication port through which the CUC port receiving unit 502 receives various information from the user management device 4 .

[0023] The CUC port receiver 502 receives settings for Talker1 and Listener2 from the user management device 4. Specifically, the CUC port receiver 502 receives an addition schedule for Talker1 to transmit an additional frame in an additional flow that is different from the multiple flows in the existing GCL. The existing GCL is a GCL that has already been stored in the GCL storage unit 503. The addition schedule also indicates the period for transmitting the additional frames.

[0024] The GCL storage unit 503 stores a GCL. The GCL is information indicating a schedule for each of the communication devices 3k to transmit frames in each of a plurality of flows. Specifically, the GCL is information indicating a schedule (see FIG. 4) for opening and closing each of a plurality of gates GT (see FIG. 3) provided in the communication device 3k. As shown in FIG. 3, when a gate GT is opened, the transmission port of the communication device 3k transmits frames held in a queue QE associated with the opened gate GT.

[0025] Specifically, as shown in FIG. 3, frames received by the receiving port of the communication device 3k (shown as circles in FIG. 3) are held in queues QE for each priority. The priority may be Class of Service (CoS) in an Ethernet frame. The transmitting port of the communication device 3k then transmits frames held in queues QE corresponding to open gates GE. In this example, the gate 304 corresponding to the queue QE with priority C7 is open, which causes frames held in the queue QE with priority C7 to be transmitted by the transmitting port of the communication device 3k. In the example shown in FIG. 3, the gates GT corresponding to the queues QE with priorities C0 to C6 are closed (the queues QW with priorities C1 to C5 are omitted in FIG. 3), which causes frames held in the queues QE with priorities C0 to C6 not to be transmitted.

[0026] In the example shown in Figure 4, five time slots, from time slot TS1 to time slot TS5, are set in the GCL. The GCL indicates, for example, that the time for which time slot TS1 is set is 15 μs. The GCL also indicates that when the time indicated by the time information corresponds to time slot TS1, the gate GT corresponding to the queue QE with priority C7 is opened ("o" in Figure 4), and the gates GT corresponding to the queue QE with priorities C0 to C6 are closed ("c" in Figure 4). Note that "the time corresponds to a time slot" means that the time refers to the time period in which the time slot is set.

[0027] When 15 μs has passed since the time corresponding to time slot TS1, the time corresponds to the next time slot TS2, and in time slot TS2, the gate GT corresponding to the queue QE with priority C5 is opened, and the gates GT corresponding to the queue QE with priorities C0 to C4, C6, and C7 are closed. In this way, when the time corresponding to each of time slots TS1 to TS5 has passed, the time again becomes time slot TS1 corresponding to the time, and this process is repeated.

[0028] For this reason, when the communication device 3k transmits frames according to the GCL, the gate GT corresponding to the queue QE of each priority is periodically opened, as shown in Fig. 5. In Fig. 5, the timing at which the gate GT is opened is indicated by a rectangle. In the example shown in Fig. 5, a time slot in which the gate GT corresponding to the queue QE of priority C7 is opened is set in the GCL of Talker1 with a first period prd1. Also, in the example shown in Fig. 5, a time slot in which the gate GT corresponding to the queue QE of priority C7 is opened is set in the GCL of the communication device 3k with a second period prd2. Also, although not shown in Fig. 5, time slots for transmitting frames of each of priorities C0 to C6 are set in a similarly periodic manner.

[0029] Furthermore, FIG. 5 shows that additional frames f1 to f4 are transmitted in the time slots set in the GCL.

[0030] The period determination unit 504 determines whether the first period prd1, which is the transmission period of the added frames indicated in the added schedule, is a divisor of the least common multiple h_prd of the frame transmission periods of each of the multiple flows in the existing GCL. At this time, the period determination unit 504 may calculate the least common multiple h_prd of the frame transmission periods of each flow. Alternatively, the period determination unit 504 may obtain the length of the GCL as the least common multiple h_prd. A period having the length of the least common multiple h_prd is called a hyper period.

[0031] If the period determination unit 504 determines that the first period prd1 is a divisor of the least common multiple h_prd, the GCL calculation unit 505 sets a time slot for each of the multiple communication devices 3k to transmit additional frames in the GCL of each of the multiple communication devices 3k at the first period prd1.

[0032] Furthermore, when it is determined that the first period prd1 is not a divisor of the least common multiple h_prd, the GCL calculation unit 505 sets the time slots for each of the communication devices 3k (k=1 to n-1) other than the last communication device (communication device 3n) among the multiple communication devices 3k to transmit additional frames to the GCL at the second period prd2. Furthermore, when it is determined that the first period prd1 is not a divisor of the least common multiple h_prd, the GCL calculation unit 505 sets the time slots for the last communication device to transmit additional frames to the GCL at the second period prd2. That is, the GCL calculation unit 505 sets the time slots for each of the communication devices 3k (k=1 to n) to transmit additional frames to the GCL at the second period prd2.

[0033] The final communication device is the communication device 3k that transmits a frame directly to Listener 2, that is, the communication device 3n that transmits a frame last.

[0034] The second period prd2 is a period that is shorter than the first period prd1 and is a divisor of the least common multiple h_prd. The sum of the second period prd2 and the non-queuing E2E (End to End) delay is shorter than the predetermined required delay. The non-queuing E2E delay is the delay that occurs when additional frames are transmitted from Talker 1 to Listener 2 without any queuing delay. The non-queuing E2E delay includes at least the sum of propagation delays. For example, when the communication system 100 forwards frames using a cut-through method, the non-queuing E2E delay includes the propagation delay and the processing delay required for transmission control. For example, when the communication system 100 forwards frames using a store-and-forward method, the non-queuing E2E delay includes the sum of the propagation delay, the processing delay, and the store delay required to store the frames. The predetermined required delay is the delay required when frames are transmitted from Talker 1 to Listener 2, and is determined by a contract with the user.

[0035] Therefore, the GCL calculation unit 505 determines the second period prd2 so that the sum of the second period prd2 and the E2E delay without queuing is shorter than a predetermined required delay.

[0036] In addition, when each communication device 3k, where k=2 to n, receives an additional frame from communication device 3(k-1), the GCL calculation unit 505 sets a time slot in the GCL so that the additional frame can be transmitted at the second period prd2 without queuing delay.

[0037] By the GCL calculation unit 505 setting the time slots in the GCL as described above, the communication device 3k transmits the additional frame in the time slot set in the second cycle prd2. At this time, the communication device 31 of the communication devices 3k may start transmitting the additional frame when a queuing delay Dq has elapsed since receiving the additional frame from Talker 1. Furthermore, when the communication device 3k, where k=2 to n, receives the additional frame from the communication device 3(k-1), it transmits the additional frame without a queuing delay.

[0038] Explaining this in more detail with reference to the example shown in Fig. 5, the communication device 31 receives the additional frame f1 when a propagation delay Dp has elapsed since Talker 1 started transmitting the additional frame f1, and transmits the additional frame f1 to the communication device 32. Furthermore, the communication device 31 receives the additional frame f2 when a propagation delay Dp has elapsed since Talker 1 started transmitting the additional frame f2, and transmits the additional frame f2 to the communication device 32 in the time slot set after the reception. Therefore, the communication device 31 transmits the additional frame f2 when a queuing delay Dq has elapsed since the reception of the additional frame f2.

[0039] Furthermore, the communication device 32 receives the additional frame fj (j is an integer between 1 and m (m=4 in this example)) when a propagation delay Dp has elapsed since the communication device 31 started transmitting the additional frame fj, and transmits it to the communication device 33 without any queuing delay. The communication device 33 receives the additional frame fj when a propagation delay Dp has elapsed since the communication device 32 started transmitting the additional frame fj, and transmits it to Listener2 without any queuing delay. Accordingly, Listener2 receives the additional frames at the second cycle prd2. Note that in the example shown in FIG. 5, the additional frames f1 to f4 for Talker1 and the communication devices 31 to 33 are shown at the timings at which they are transmitted, and the additional frames f1 to f4 for Listener2 are shown at the timings at which they are received.

[0040] Thus, in the first embodiment, Listener2 receives additional frames transmitted from Talker1 at the first cycle prd1 at the second cycle prd2. As a result, jitter of a maximum length equal to ROUNDUP(prd1 / prd2)×prd2=a×prd2 occurs. ROUNDUP(prd1 / prd2) is the value obtained by dividing the first cycle prd1 by the second cycle prd2 and rounding up to the nearest integer. Furthermore, a is a positive integer. Therefore, Listener2 may perform any processing to absorb jitter using application software, etc.

[0041] The CUC transmission port 506 is a communication port for the CUC port transmission unit 507 to transmit various information to the user management device 4 .

[0042] The CUC port transmitter 507 transmits various information to the user management device 4 via the CUC transmission port 506. The CUC port transmitter 507 may transmit to the user management device 4 information indicating that the last communication device transmits frames to Listener2 at the second cycle prd2.

[0043] The TSN-SW transmission port 508 is a communication port through which the TSN-SW port transmission unit 509 transmits various information to the communication device 3k.

[0044] The TSN-SW port transmitting unit 509 transmits various information to the communication device 3k via the TSN-SW transmitting port 508. For example, the TSN-SW port transmitting unit 509 transmits the GCL in which the time slot is set by the GCL calculating unit 505 as described above to the communication device 3k.

[0045] <Control device operation> Here, the operation of the control device 5 according to the first embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the operation of the control device 5 according to the first embodiment. The operation of the control device 5 described with reference to Fig. 6 corresponds to an example of a control method of the control device 5 according to the first embodiment. As described above, the control device 5 includes a GCL storage unit 503 that stores a GCL indicating a schedule for each of the communication devices 3k to transmit frames in each of a plurality of flows.

[0046] In step S11, the CUC port receiving unit 502 receives an additional schedule for Talker1 to transmit an additional frame in an additional flow that is different from the multiple flows of the existing GCL.

[0047] In step S12, the period determination unit 504 determines whether the first period prd1, which is the transmission period of the additional frame indicated in the additional schedule, is a divisor of the least common multiple h_prd of the frame transmission periods of each of the multiple flows of the existing GCL.

[0048] If it is determined in step S12 that the first period prd1 is a divisor of the least common multiple h_prd, then in step S13, the GCL calculation unit 505 sets the time slots for each of the multiple communication devices 3k to transmit additional frames to their respective GCLs at the first period prd1.

[0049] If it is determined in step S12 that the first cycle prd1 is not a divisor of the least common multiple h_prd, in step S14 the GCL calculation unit 505 sets the time slots for each of the multiple communication devices 3k to transmit additional frames in the GCL using the second cycle prd2. Specifically, the GCL calculation unit 505 sets the time slots for each of the multiple communication devices 3k (k=1 to n-1) that are different from the last communication device that transmits frames directly to Listener 2 to transmit additional frames in the GCL using the second cycle prd2. The GCL calculation unit 505 also sets the time slots for the last communication device (communication device 3n) to transmit additional frames in the GCL using the second cycle prd2.

[0050] In step S15, the TSN-SW port transmitting unit 509 transmits the GCL in which the time slot is set in step S13 or step S14 to the communication device 3k.

[0051] As described above, according to the first embodiment, the communication system 100 includes a Talker 1 that transmits delay-guaranteed frames, a plurality of communication devices 3k that sequentially forward the frames, a Listener 2 that receives the frames forwarded by the plurality of communication devices 3k, and a control device 5 that controls the plurality of communication devices 3k. The control device 5 also includes a GCL storage unit 503 that stores a GCL indicating a schedule for each of the communication devices 3k to transmit frames in each of a plurality of flows. The control device 5 also includes a CUC port receiving unit 502 that receives an addition schedule for Talker 1 to transmit additional frames in an additional flow that is different from the plurality of flows, and a period determination unit 504 that determines whether a first period prd1, which is a transmission period of the additional frames indicated in the addition schedule, is a divisor of the least common multiple h_prd of the frame transmission periods of each of the plurality of flows. The control device 5 also includes a GCL calculation unit 505 that, if it is determined that the first cycle prd1 is a divisor of the least common multiple h_prd, sets the time slots for each of the multiple communication devices 3k to transmit additional frames to the GCL at the first cycle prd1, and, if it is determined that the first cycle prd1 is not a divisor of the least common multiple h_prd, sets the time slots for each of the multiple communication devices 3k (k=1 to n-1) that is different from the last communication device that transmits frames directly to the Listener 2 to the GCL at a second cycle prd2 that is shorter than the first cycle prd1 and is a divisor of the least common multiple h_prd. The control device 5 also includes a TSN-SW port transmission unit 509 that transmits the GCL in which the time slots are set to the communication device 3k.

[0052] This allows the communication system 100 to set a time slot for transmitting additional frames in an additional flow without changing the length of the GCL when the additional flow is added, thereby preventing the complexity of communication control from increasing and service interruptions from occurring.

[0053] Furthermore, according to the first embodiment, the GCL calculation unit 505 determines the second period prd2 so that the sum of the second period prd2 and the non-queuing E2E delay is shorter than a predetermined required delay. This allows the communication system 100 to set a time slot for transmitting additional frames in the flow without changing the predetermined required delay determined by a contract with a user or the like and without changing the length of the GCL. Therefore, it is possible to prevent an increase in the complexity of communication control and avoid service interruptions while maintaining communication quality.

[0054] <<Second embodiment>> The overall configuration of the second embodiment will be described below. In the second embodiment, the same functional units as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0055] 1, the communication system 100-1 includes a Talker 1, a Listener 2, a plurality of communication devices 3k, and a user management device 4. The communication system 100-1 also includes a control device 5-1 instead of the control device 5 shown in FIG.

[0056] <Control device configuration> The control device 5-1 controls a plurality of communication devices 3k that transfer frames from Talker 1 to Listener 2. The control device 5-1, like the control device 5 shown in Fig. 2, includes a CUC receiving port 501, a CUC port receiving unit 502, a GCL storage unit 503, a periodicity determining unit 504, a CUC transmitting port 506, a CUC port transmitting unit 507, a TSN-SW transmitting port 508, and a TSN-SW port transmitting unit 509. The control device 5-1 also includes a GCL calculation unit 505-1 instead of the GCL calculation unit 505 shown in Fig. 2. Like the control device 5, the control device 5-1 is, for example, a CUC.

[0057] The GCL calculation unit 505-1 is configured by a controller.

[0058] Similar to the GCL calculation unit 505 of the first embodiment, when the period determination unit 504 determines that the first period prd1 is a divisor of the least common multiple h_prd, the GCL calculation unit 505-1 sets the time slots for each of the multiple communication devices 3k to transmit additional frames in the GCL at the first period prd1.

[0059] Similar to the GCL calculation unit 505 of the first embodiment, when it is determined that the first period prd1 is not a divisor of the least common multiple h_prd, the GCL calculation unit 505-1 sets the time slots for each of the communication devices 3k (k=1 to n-1) other than the last communication device among the multiple communication devices 3k to transmit additional frames in the GCL with the second period prd2.

[0060] As in the first embodiment, the second period prd2 is a divisor of the least common multiple h_prd and is shorter than the first period prd1. In the second embodiment, the sum of the second period prd2, the non-queuing E2E delay, and the added delay d_add (described in detail later) is shorter than the predetermined required delay. Therefore, the GCL calculation unit 505-1 determines the second period prd2 so that the sum of the second period prd2, the non-queuing E2E delay, and the added delay d_add is shorter than the predetermined required delay.

[0061] Furthermore, if it is determined that the first period prd1 is not a divisor of the least common multiple h_prd, the GCL calculation unit 505-1 sets a time slot for the last communication device to transmit an additional frame to the GCL at the first period prd1. At this time, the GCL calculation unit 505-1 sets the time slot to the GCL so that the last communication device will transmit the first additional frame when the added delay d_add has elapsed since the last communication device received the first additional frame in the additional flow.

[0062] The added delay d_add is a delay added so that Listener2 receives an additional frame in the first period prd1. Therefore, the added delay d_add is, at most, ROUNDUP(prd1 / prd2)×prd2=a×prd2.

[0063] As a result, communication device 3k where k=1 to n-1 transmits the additional frame received from Talker1 in the time slot set with the second cycle prd2. Also, communication device 3k where k=n (i.e., the last communication device) transmits the first additional frame when the added delay d_add has elapsed since receiving the first additional frame in the additional flow from communication device 3(n-1). Also, communication device 3k where k=n (i.e., the last communication device) transmits the second or subsequent additional frames received from communication device 3(n-1) in the first cycle prd1.

[0064] 7, the communication device 31 receives additional frame f1 when a propagation delay Dp has elapsed since Talker 1 started transmitting additional frame f1, and transmits the additional frame f1. The communication device 31 also receives additional frame f2 when a propagation delay Dp has elapsed since Talker 1 started transmitting additional frame f2, and transmits additional frame f2 in the following time slot.

[0065] Furthermore, the communication device 32 receives the additional frame fj transmitted from the communication device 31 when a propagation delay Dp has elapsed since the communication device 31 started transmitting the additional frame fj, and transmits the additional frame fj without a queuing delay.

[0066] The communication device 33 receives the additional frame f1 when a propagation delay Dp has elapsed since the communication device 32 started transmitting the additional frame f1, and transmits the additional frame f1 when an added delay d_add has elapsed since the reception of the additional frame f1. The communication device 33 also receives the additional frames f2 to f4 when a propagation delay Dp has elapsed since the communication device 32 started transmitting each of the additional frames f2 to f4, and transmits the additional frames f2 to f4 at a first cycle prd1.

[0067] <Control device operation> Here, the operation of the control device 5-1 according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart showing an example of the operation of the control device 5-1 according to the second embodiment. The operation of the control device 5-1 described with reference to Fig. 8 corresponds to an example of a control method of the control device 5-1 according to the second embodiment. As described above, the control device 5-1 includes a GCL storage unit 503 that stores a GCL indicating a schedule for each of the communication devices 3k to transmit frames in each of a plurality of flows.

[0068] The operations from step S21 to step S23 are the same as the operations from step S11 to step S13 in the first embodiment, respectively.

[0069] If it is determined in step S22 that the first period prd1 is not a divisor of the least common multiple h_prd, then in step S24, the GCL calculation unit 505-1 sets the time slots for each of the communication devices 3k (k=1 to n-1) other than the last communication device among the multiple communication devices 3k to transmit additional frames to the GCL using a second period prd2 that is shorter than the first period prd1 and is a divisor of the least common multiple h_prd.

[0070] In step 25, the GCL calculation unit 505-1 sets a time slot for the last communication device (communication device 3n) to transmit an additional frame in the GCL at a first period prd1. At this time, the GCL calculation unit 505-1 sets the time slot in the GCL so that the last communication device transmits the first additional frame when the added delay d_add has elapsed since the last communication device received the first additional frame in the additional flow.

[0071] The operation in step S26 is similar to the operation in step S15 in the first embodiment.

[0072] As described above, according to the second embodiment, in the communication system 100-1, if it is determined that the first cycle prd1 is not a divisor of the least common multiple h_prd, the GCL calculation unit 505-1 sets the time slots for the last communication device to transmit additional frames in the GCL at the first cycle prd1. This allows the communication system 100-1 to continue realizing deterministic cycle communication in which Listener2 receives additional frames at the same cycle as Talker1 transmits additional frames.

[0073] Furthermore, according to the second embodiment, in the communication system 100-1, the GCL calculation unit 505-1 determines the second period prd2 so that the sum of the second period prd2, the non-queuing E2E delay, and the added delay d_add is shorter than a predetermined required delay. This allows the communication system 100-1 to set a time slot for transmitting additional frames in the flow without changing the required delay determined by a contract with the user or the like, and without changing the length of the GCL. Therefore, it is possible to prevent the complexity of communication control from increasing and avoid service interruptions while maintaining communication quality.

[0074] <Program> The above-described control device 5 and control device 5-1 can each be realized by a computer 601. Furthermore, a program for causing each of the control devices 5 and 5-1 to function may be provided. Furthermore, the program may be stored on a storage medium or provided via a network. FIG. 9 is a block diagram showing a schematic configuration of a computer 601 that functions as each of the control devices 5. The same applies to a computer that functions as each of the control devices 5-1. Here, the computer 601 may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notepad, or the like. The program instructions may be program code, code segments, or the like for executing necessary tasks.

[0075] 9, a computer 601 includes a processor 610, a read-only memory (ROM) 620, a random access memory (RAM) 630, a storage 640, an input unit 650, an output unit 660, and a communication interface (I / F) 670. Each component is communicably connected to one another via a bus 680. The processor 610 is specifically a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), a digital signal processor (DSP), a system on a chip (SoC), or the like, and may be configured by a plurality of processors of the same type or different types.

[0076] The processor 610 controls each component and performs various arithmetic processing. That is, the processor 610 reads a program from the ROM 620 or the storage 640 and executes the program using the RAM 630 as a work area. The processor 610 controls each component and performs various arithmetic processing in accordance with the program stored in the ROM 620 or the storage 640. In the above-described embodiment, the program according to the present disclosure is stored in the ROM 620 or the storage 640.

[0077] The program may be stored in a storage medium readable by the computer 601. Using such a storage medium, the program can be installed in the computer 601. Here, the storage medium on which the program is stored may be a non-transitory storage medium. The non-transitory storage medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory. Furthermore, the program may be downloaded from an external device via a network.

[0078] The ROM 620 stores various programs and frames. The RAM 630 serves as a working area for temporarily storing programs or frames. The storage 640 is configured with an HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs and frames, including the operating system.

[0079] The input unit 650 includes one or more input interfaces that receive input operations from a user and acquire information based on the user operations. For example, the input unit 650 may be, but is not limited to, a pointing device, a keyboard, a mouse, etc.

[0080] The output unit 660 includes one or more output interfaces that output information. For example, the output unit 660 is, but is not limited to, a display that outputs information as a video or a speaker that outputs information as an audio. If the output unit 660 is a touch panel display, it also functions as the input unit 650.

[0081] The communication interface 670 is an interface for communicating with external devices.

[0082] The following additional notes are provided regarding the above-described embodiments.

[0083] [Additional note 1] A communication system comprising: a transmitting terminal that transmits delay-guaranteed frames; a plurality of communication devices that sequentially transfer the frames; a receiving terminal that receives the frames transferred by the plurality of communication devices; and a control device that controls the plurality of communication devices, the control device includes a memory that stores a gate control list indicating a schedule for each of the communication devices to transmit frames in each of a plurality of flows, and a controller; The controller the transmitting terminal receiving an additional schedule for transmitting additional frames in an additional flow different from the plurality of flows, the transmitting terminal receiving an additional schedule for transmitting additional frames in an additional flow different from the plurality of flows, determining whether a first period, which is a transmission period of the additional frames indicated in the additional schedule, is a divisor of the least common multiple of the frame transmission periods of the plurality of flows; If it is determined that the first period is a divisor of the least common multiple, the time slots for the plurality of communication devices to transmit the additional frames are set to the first period in the respective gate control lists; if it is determined that the first period is not a divisor of the least common multiple, the time slots for the plurality of communication devices to transmit the additional frames are set to the gate control lists of the respective communication devices other than the last communication device that directly transmits the additional frames to the receiving terminal, with a second period that is shorter than the first period and is a divisor of the least common multiple; A communication system that transmits a gate control list in which the time slots are set to the communication device. [Additional note 2] The communication system described in Appendix 1, wherein if the controller determines that the first period is not a divisor of the least common multiple, the controller sets the time slot in which the last communication device transmits the additional frame in the gate control list at the second period. [Additional note 3] The communication system described in Appendix 1, wherein, if it is determined that the first period is not a divisor of the least common multiple, the controller sets a time slot for the last communication device to transmit the additional frame in the gate control list at the first period. [Additional note 4] the controller sets the time slot in the gate control list so that the last communication device transmits the first additional frame when a given delay has elapsed since the last communication device received the first additional frame in the additional flow; 4. The communication system described in claim 3, wherein the given delay is a delay given to the receiving terminal so that the additional frame is received in the first period. [Additional note 5] The communication system described in Supplementary Claim 2, wherein the controller determines the second period so that the sum of the second period and the delay that occurs when the additional frame is transmitted from the transmitting terminal to the receiving terminal without queuing delay is shorter than a predetermined required delay. [Additional note 6] The communication system described in Supplementary Claim 4, wherein the controller determines the second period so that the sum of the second period, the delay that occurs when the additional frame is transmitted from the transmitting terminal to the receiving terminal without queuing delay, and the given delay is shorter than a predetermined required delay. [Additional note 7] A control device that controls a plurality of communication devices that transfer frames from a transmitting terminal to a receiving terminal, The method includes: a memory storing a gate control list indicating a schedule for each of the communication devices to transmit frames in each of a plurality of flows; and a controller, the controller including: the transmitting terminal receiving an additional schedule for transmitting additional frames in an additional flow different from the plurality of flows, the transmitting terminal receiving an additional schedule for transmitting additional frames in an additional flow different from the plurality of flows, determining whether a first period, which is a transmission period of the additional frames indicated in the additional schedule, is a divisor of the least common multiple of the frame transmission periods of the plurality of flows; If it is determined that the first period is a divisor of the least common multiple, the time slots for the plurality of communication devices to transmit the additional frames are set to the first period in the respective gate control lists; if it is determined that the first period is not a divisor of the least common multiple, the time slots for the plurality of communication devices to transmit the additional frames are set to the gate control lists of the respective communication devices other than the last communication device that directly transmits the additional frames to the receiving terminal, with a second period that is shorter than the first period and is a divisor of the least common multiple; A control device transmits a gate control list in which the time slots are set to the communication device. [Additional note 8] A non-transitory storage medium storing a program executable by a computer, the non-transitory storage medium storing the program causing the computer to operate as the control device described in appended claim 7.

[0084] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0085] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be interpreted as being limited by the above-described embodiments, and various modifications or alterations are possible without departing from the scope of the claims. For example, multiple building blocks shown in the block diagrams of the embodiments can be combined into one, or one building block can be divided. [Explanation of symbols]

[0086] 1. Transmitting terminal (Talker) 2. Listener 3k communication equipment 4. User management device 5, 5-1 Control device 100, 100-1 Communication Systems 501 CUC receiving port (user-configured receiving port) 502 CUC port receiver (user-defined receiver) 503 GCL storage section 504 Period determination section 505, 505-1 GCL calculation section 506 CUC outgoing communication port (user-configured outgoing port) 507 CUC Transmitter (User-defined Transmitter) 508 TSN-SW transmission port (communication port for communication device) 509 TSN-SW port transmitter (transmitter for communication device) 601 Computer 610 processor 620 ROM 630 RAM 640 Storage 650 Input section 660 Output Section 670 Communication Interface 680 Bus

Claims

1. A communication system comprising: a transmitting terminal that transmits delay-guaranteed frames; a plurality of communication devices that sequentially transfer the frames; a receiving terminal that receives the frames transferred by the plurality of communication devices; and a control device that controls the plurality of communication devices, The control device a gate control list storage unit that stores a gate control list indicating a schedule for each of the communication devices to transmit frames in each of a plurality of flows; a user setting receiving unit that receives an additional schedule for the transmitting terminal to transmit additional frames in an additional flow different from the plurality of flows; a period determination unit that determines whether a first period, which is a transmission period of the additional frame indicated in the additional schedule, is a divisor of the least common multiple of the frame transmission periods of the plurality of flows; a gate control list calculation unit that, when it is determined that the first period is a divisor of the least common multiple, sets the time slots for the plurality of communication devices to transmit the additional frames at the first period in the gate control list of each of the plurality of communication devices, and, when it is determined that the first period is not a divisor of the least common multiple, sets the time slots for the plurality of communication devices, other than a last communication device that directly transmits the additional frames to the receiving terminal, at a second period that is shorter than the first period and is a divisor of the least common multiple in the gate control list; a communication device transmitter that transmits to the communication device a gate control list in which the time slots are set.

2. 2. The communication system according to claim 1, wherein when it is determined that the first period is not a divisor of the least common multiple, the gate control list calculation unit sets the time slot in which the last communication device transmits the additional frame in the gate control list with the second period.

3. 2. The communication system according to claim 1, wherein when it is determined that the first period is not a divisor of the least common multiple, the gate control list calculation unit sets a time slot for the last communication device to transmit the additional frame in the gate control list at the first period.

4. the gate control list calculation unit sets the time slot in the gate control list so that the last communication device transmits the first additional frame when an added delay has elapsed since the last communication device received the first additional frame in the added flow; The communication system according to claim 3 , wherein the given delay is a delay given to the receiving terminal so that the receiving terminal receives the additional frame in the first period.

5. 3. The communication system according to claim 2, wherein the gate control list calculation unit determines the second period so that the sum of the second period and a delay that occurs when the additional frame is transmitted from the transmitting terminal to the receiving terminal without a queuing delay is shorter than a predetermined required delay.

6. 5. The communication system according to claim 4, wherein the gate control list calculation unit determines the second period so that the sum of the second period, the delay that occurs when the additional frame is transmitted from the transmitting terminal to the receiving terminal without queuing delay, and the given delay is shorter than a predetermined required delay.

7. A control device that controls a plurality of communication devices that transfer frames from a transmitting terminal to a receiving terminal, a gate control list storage unit that stores a gate control list indicating a schedule for each of the communication devices to transmit frames in each of a plurality of flows; a user setting receiving unit that receives an additional schedule for the transmitting terminal to transmit additional frames in an additional flow different from the plurality of flows; a period determination unit that determines whether a first period, which is a transmission period of the additional frame indicated in the additional schedule, is a divisor of the least common multiple of the frame transmission periods of the plurality of flows; a gate control list calculation unit that, when it is determined that the first period is a divisor of the least common multiple, sets the time slots for the plurality of communication devices to transmit the additional frames at the first period in the gate control list of each of the plurality of communication devices, and, when it is determined that the first period is not a divisor of the least common multiple, sets the time slots for the plurality of communication devices, other than a last communication device that directly transmits the additional frames to the receiving terminal, at a second period that is shorter than the first period and is a divisor of the least common multiple in the gate control list; a communication device transmitter that transmits a gate control list in which the time slots are set to the communication device; A control device comprising:

8. A program for causing a computer to function as the control device according to claim 7.

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