WO2024127519A1 - Communication system, control device, and program - Google Patents

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

COMMUNICATION SYSTEM, CONTROL DEVICE, AND PROGRAM

This disclosure relates to a communication system, a control device, and a program.

In communication systems that use TAS (Time Aware Shaper) technology, a technology is known that guarantees delays using a Gate Control List (GCL) that indicates the schedule of communication devices (see, for example, non-patent document 1).

Generally, the GCL has a length that is the least common multiple of the periods in which frames of multiple flows are transmitted. Since the communication device repeats frame transmission according to the GCL, frames in multiple flows can be transmitted using deterministic periodic communication.

Yuhei Kawakami and 5 others, "Applying Time-aware Shaper Considering User Identifier to Service Provider Network," IEEE 19th Annual Consumer Communications & Networking Conference, 2022.

However, when adding a time slot for transmitting an additional frame by an additional flow to a GCL designed as described above, it may not be possible to represent the repetition of 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 multiple flows shown in the existing GCL, it is not possible to represent the repetition of 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 multiple flows and the periods for transmitting additional frames shown in the existing GCL.

The GCL designed in this way is longer than existing GCLs, which increases the complexity of communication control, including scheduling. In addition, to change the length of the GCL, the communication system in operation must be stopped, which means that the services provided by the communication system must be interrupted.

The purpose of this disclosure, made in consideration of these circumstances, is to provide a communications system, control device, and program that can prevent the complexity of communications control from increasing when new flows are added, and can avoid interruptions to services.

In order to solve the above problem, the communication system according to the present disclosure is a communication system including a transmitting terminal that transmits a delay-guaranteed frame, a plurality of communication devices that transfer the frame in sequence, a receiving terminal that receives the frame transferred by the plurality of communication devices, and a control device that controls the plurality of communication devices, the control device including 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-set 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 of the additional frames indicated in the additional schedule, the first period being a transmission period of the frames in each of the plurality of flows. a period determination unit that determines whether the first period is a divisor of the least common multiple of the communication periods; a gate control list calculation unit that sets the time slots for the multiple communication devices to transmit the additional frames in the first period in the gate control list of each of the multiple communication devices when it is determined that the first period is a divisor of the least common multiple, and when 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, in the gate control list in 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 devices.

In order to solve the above problem, the 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 each of a plurality of flows, a user-set 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, which 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 the frames in each of 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 the frames in each of the plurality of flows. The system includes a gate control list calculation unit that sets the time slots for the multiple communication devices to transmit the additional frames in the first period in the respective gate control lists when it is determined that the first period is a divisor of the least common multiple, and when 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 directly transmits the additional frame to the receiving terminal, in the gate control list in a second period that is shorter than the first period and is a divisor of the least common multiple, among the multiple communication devices, and a communication device transmission unit that transmits the gate control list in which the time slots are set to the communication devices.

To solve the above problem, the program disclosed herein causes a computer to operate as the control device described above.

The communication system, control device, and program disclosed herein can prevent communication control from becoming too complicated and avoid service interruptions.

1 is a schematic diagram of a communication system according to a first embodiment. FIG. 2 is a diagram illustrating an example of a control device illustrated in FIG. 1 . FIG. 2 is a schematic diagram for explaining queues and gates. FIG. 2 is a schematic diagram showing an example of a GCL. 11 is a diagram showing an example of timing at which a frame is transmitted according to a GCL in which a time slot is set by a control device according to the first embodiment; FIG. 5 is a flowchart showing an example of an operation of the control device according to the first embodiment. 13 is a diagram showing an example of timing at which a frame is transmitted according to a GCL in which a time slot is set by a control device according to a second embodiment; FIG. 10 is a flowchart showing an example of an operation of the control device according to the second embodiment. FIG. 2 is a hardware block diagram of a control device.

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.

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 being 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 the transfer in a time-division manner using TAS, so delay and jitter are controlled.

Talker 1 transmits frames that are guaranteed to have a delay. Specifically, Talker 1 transmits frames to Listener 2 via multiple communication devices 3k. In addition, 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.

　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.

Communication device 3k sequentially forwards frames sent from Talker 1 to Listener 2. Specifically, communication device 3k receives frames from other devices and transmits frames to other devices. Communication device 3k is a communication network device, and can be, for example, a switch. In ST communication, communication device 3k performs time-division forwarding control using TAS.

In the following explanation, communication device 3k transfers data in ascending order of k. That is, a frame transmitted from Talker 1 is first received by communication device 31, and is then transferred in the order of communication devices 31, 32, ... 3(n-1), 3n. Communication device 3n also transmits frames directly to Listener 2. In the example shown in FIG. 1, communication device 31 receives a frame from Talker 1 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 Listener 2.

The user management device 4 manages the settings of Talker 1 and Listener 2. Specifically, the user management device 4 manages the schedule in which Talker 1 transmits frames through each of multiple flows. Furthermore, when an additional schedule is added for Talker 1 to transmit an additional frame through 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 need to include a user management device 4, and in such a configuration, the control device 5 included in the communication system 100 can send and receive various information with a device having functions equivalent to those of the user management device 4.

<Configuration of the control device>
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-defined receiving port) 501, a CUC port receiving unit (user-defined receiving unit) 502, a GCL storage unit (gate control list storage unit) 503, a periodicity determination unit 504, a GCL calculation unit (gate control list calculation unit) 505, a CUC transmission communication port (user-defined transmission port) 506, a CUC port transmitting unit (user-defined transmitting unit) 507, a TSN-SW transmission port (transmission port for communication device) 508, and a TSN-SW port transmitting unit (transmission unit for communication device) 509. The control device 5 is, for example, a Central Network Controller (CUC).

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

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.

The CUC port receiver 502 receives settings for Talker 1 and Listener 2 from the user management device 4. Specifically, the CUC port receiver 502 receives an additional schedule for Talker 1 to transmit additional frames in an additional flow that is different from the multiple flows in the existing GCL. The existing GCL is a GCL that is already stored in the GCL storage unit 503. The additional schedule also indicates the period for transmitting additional frames.

The GCL storage unit 503 stores the GCL. The GCL is information indicating a schedule for each of the communication devices 3k to transmit frames in each of the multiple flows. Specifically, the GCL is information indicating a schedule (see FIG. 4) for opening and closing each of the multiple 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 the queue QE associated with the opened gate GT.

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

In the example shown in FIG. 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 queue QE with priority C7 is opened (indicated as "o" in FIG. 4), and the gate GT corresponding to queue QE with priorities C0 to C6 is closed (indicated as "c" in FIG. 4). Note that "the time corresponds to a time slot" means that the time refers to the time period in which the time slots are set.

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 queue QE with priority C5 is opened, and the gates GT corresponding to queue QE with priorities C0 to C4, C6, and C7 are closed. In this way, when the time has passed the time corresponding to time slots TS1 to TS5, it again becomes time slot TS1 corresponding to the time, and this is repeated.

For this reason, when communication device 3k transmits frames according to the GCL, the gate GT corresponding to the queue QE of each priority is opened periodically, 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 with a first period prd1 in the GCL of Talker 1. 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 with a second period prd2 in the GCL of communication device 3k. Also, although not shown in FIG. 5, time slots for transmitting frames of each priority from C0 to C6 are set periodically in the same manner.

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

The period determination unit 504 determines whether the first period prd1, which is the transmission period of the additional frames shown 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 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. The period determination unit 504 may also obtain the length of the GCL as the least common multiple h_prd. A period having a length of the least common multiple h_prd is called a hyper period.

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 an additional frame in the first period prd1 in each GCL.

Further, when the GCL calculation unit 505 determines that the first period prd1 is not a divisor of the least common multiple h_prd, it 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.Further, when the GCL calculation unit 505 determines that the first period prd1 is not a divisor of the least common multiple h_prd, it sets the time slots for the last communication device to transmit additional frames to the GCL at the second period prd2.In other words, 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.

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

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 queuing-free E2E (End to End) delay is shorter than the specified required delay. The queuing-free E2E delay is a delay that occurs when an additional frame is transmitted from Talker 1 to Listener 2 without a queuing delay. The queuing-free E2E delay includes at least the sum of the propagation delay. For example, when the communication system 100 transfers frames using a cut-through method, the queuing-free E2E delay includes the propagation delay and the processing delay required for transmission control. For example, when the communication system 100 transfers frames using a store-and-forward method, the queuing-free E2E delay includes the sum of the propagation delay, the processing delay, and the store delay required to store the frames. The specified required delay is a delay that is requested when a frame is transmitted from Talker 1 to Listener 2, and is determined by a contract with the user.

For this reason, 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 the specified required delay.

In addition, when 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 is transmitted at the second period prd2 without queuing delay.

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

To explain in more detail with reference to the example shown in FIG. 5, communication device 31 receives additional frame f1 when propagation delay Dp has elapsed since Talker 1 started transmitting additional frame f1, and transmits the additional frame f1 to communication device 32. Furthermore, communication device 31 receives additional frame f2 when propagation delay Dp has elapsed since Talker 1 started transmitting additional frame f2, and transmits additional frame f2 to communication device 32 in the time slot set after the reception. Therefore, communication device 31 transmits additional frame f2 when queuing delay Dq has elapsed since receiving additional frame f2.

Furthermore, when the propagation delay Dp has elapsed since the communication device 31 started transmitting the additional frame fj, the communication device 32 receives the additional frame fj (j is an integer from 1 to m (m=4 in this example)) and transmits it to the communication device 33 without a queuing delay. Further, the communication device 33 receives the additional frame fj when the propagation delay Dp has elapsed since the communication device 32 started transmitting the additional frame fj and transmits it to the Listener 2 without a queuing delay. Accordingly, the Listener 2 receives the additional frames at the second period prd2. Note that in the example shown in FIG. 5, the additional frames f1 to f4 for Talker 1 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 Listener 2 are shown at the timings at which they are received.

In this way, in the first embodiment, Listener 2 receives additional frames transmitted from Talker 1 with the first period prd1 with the second period prd2. As a result, jitter with a length of up to ROUNDUP(prd1/prd2) x prd2 = a x prd2 occurs. ROUNDUP(prd1/prd2) is the value obtained by dividing the first period prd1 by the second period prd2 and rounding up to an integer. In addition, a is a positive integer. Therefore, Listener 2 may execute any process to absorb jitter using application software, etc.

The CUC transmission port 506 is a communication port through which the CUC port transmission unit 507 transmits various information to the user management device 4.

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

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.

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

<Operation of the control device>
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.

In step S11, the CUC port receiver 502 receives an additional schedule for Talker 1 to transmit an additional frame in an additional flow that is different from the multiple flows of the existing GCL.

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 in each of the multiple flows of the existing GCL.

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

If it is determined in step S12 that the first period 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 second period prd2 to the GCL. 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 a frame directly to Listener2 to transmit additional frames in the GCL in the second period 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 in the second period prd2.

In step S15, the TSN-SW port transmission unit 509 transmits the GCL for which the time slot was set in step S13 or step S14 to the communication device 3k.

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 the plurality of flows. The control device 5 also includes a CUC port receiving unit 502 that receives an additional schedule for Talker 1 to transmit additional frames in an additional flow different from the plurality of flows, and a period determination unit 504 that determines whether a first period prd1, which is the transmission period of the additional frames indicated in the additional schedule, is a divisor of the least common multiple h_prd of the transmission periods of the frames in each of the plurality of flows. The control device 5 also includes a GCL calculation unit 505 that, when 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 in the first cycle prd1 in the GCL, and when it is determined that the first cycle prd1 is not a divisor of the least common multiple h_prd, sets the time slots for the communication device 3k (k=1 to n-1) other than the last communication device that transmits a frame directly to the Listener 2 among the multiple communication devices 3k to transmit additional frames in the GCL in a second cycle prd2 that is a divisor of the least common multiple h_prd and is shorter than the first cycle prd1. 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.

As a result, when an additional flow is added, the communication system 100 can set a time slot for transmitting additional frames in that flow without changing the length of the GCL. This makes it possible to prevent the complexity of communication control from increasing and to avoid interruptions to services.

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 E2E delay without queuing 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 the user, etc., and without changing the length of the GCL. Therefore, it is possible to prevent the complexity of communication control from increasing while maintaining communication quality, and to avoid interruptions to services.

<<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.

Similar to the communication system 100 shown in FIG. 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. 1.

<Configuration of the control device>
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 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, similar to the control device 5 shown in Fig. 2. The control device 5-1 also includes a GCL calculation unit 505-1 instead of the GCL calculation unit 505 shown in Fig. 2. The control device 5-1 is, for example, a CUC, similar to the control device 5.

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

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 first period prd1 in each GCL.

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 transmitting additional frames by each of the communication devices 3k (k = 1 to n-1) other than the last communication device among the multiple communication devices 3k to the GCL with the second period prd2.

Similar to the first embodiment, the second period prd2 is a divisor of the least common multiple h_prd and is a value shorter than the first period prd1. Also, in the second embodiment, the sum of the second period prd2, the non-queuing E2E delay, and the granted delay d_add, which will be described in detail later, is shorter than a 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 granted delay d_add is shorter than the predetermined required delay.

In addition, if the GCL calculation unit 505-1 determines that the first period prd1 is not a divisor of the least common multiple h_prd, it sets the 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 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 addition flow.

The added delay d_add is the delay added so that Listener2 receives additional frames in the first period prd1. Therefore, the added delay d_add is, at most, ROUNDUP(prd1/prd2) x prd2 = a x prd2.

As a result, communication device 3k where k = 1 to n-1 transmits additional frames received from Talker 1 in the time slot set with the second cycle prd2. Furthermore, 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). Furthermore, communication device 3k where k = n (i.e., the last communication device) transmits additional frames received from communication device 3(n-1) for the second time onwards in the first cycle prd1.

To explain this in more detail with reference to the example shown in FIG. 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.

The communication device 32 also 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.

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

<Operation of the control device>
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.

The operations from step S21 to step S23 are similar to the operations from step S11 to step S13 in the first embodiment, respectively.

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

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

The operation of step S26 is similar to the operation of step S15 in the first embodiment.

As described above, according to the second embodiment, in the communication system 100-1, if the GCL calculation unit 505-1 determines that the first cycle prd1 is not a divisor of the least common multiple h_prd, it sets the time slot for the last communication device to transmit additional frames to the GCL with the first cycle prd1. This allows the communication system 100-1 to continue to realize definite cycle communication in which the Listener 2 receives additional frames with the same cycle as the Talker 1 transmits additional frames.

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 predetermined required delay determined by a contract with the user, etc., and without changing the length of the GCL. Therefore, it is possible to prevent the complexity of communication control from increasing while maintaining communication quality, and to avoid interruptions to services.

<Program>
Each of the above-mentioned control devices 5 and 5-1 can be realized by a computer 601. Also, a program for causing each of the control devices 5 and 5-1 to function may be provided. Also, the program may be stored in a storage medium or provided through a network. FIG. 9 is a block diagram showing a schematic configuration of a computer 601 functioning as each of the control devices 5. The same is true for a computer functioning 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 performing necessary tasks.

As shown in FIG. 9, computer 601 includes a processor 610, a ROM (Read Only Memory) 620, a RAM (Random Access Memory) 630, storage 640, an input section 650, an output section 660, and a communication interface (I/F) 670. Each component is connected to each other via a bus 680 so that they can communicate with each other. Specifically, processor 610 is a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), etc., and may be composed of multiple processors of the same or different types.

Processor 610 controls each component and executes various types of arithmetic processing. That is, processor 610 reads a program from ROM 620 or storage 640, and executes the program using RAM 630 as a working area. Processor 610 controls each of the components and executes various types of arithmetic processing according to the program stored in ROM 620 or storage 640. In the above-described embodiment, the program related to the present disclosure is stored in ROM 620 or storage 640.

The program may be stored in a storage medium that is readable by computer 601. Using such a storage medium, the program can be installed in computer 601. Here, the storage medium in 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. In addition, the program may be in a form in which it is downloaded from an external device via a network.

ROM 620 stores various programs and frames. RAM 630 temporarily stores programs or frames as a working area. Storage 640 is composed of a HDD (Hard Disk Drive) or SSD (Solid State Drive), and stores various programs and frames including the operating system.

The input unit 650 includes one or more input interfaces that accept input operations from a user and acquire information based on the user's operations. For example, the input unit 650 is a pointing device, a keyboard, a mouse, etc., but is not limited to these.

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

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

The following notes are further provided with respect to the above embodiment.

[Additional Note 1]
A communication system comprising: a transmitting terminal that transmits a delay-guaranteed frame; a plurality of communication devices that sequentially transfer the frame; a receiving terminal that receives the frame 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 receives an add schedule for transmitting an add frame in an add flow different from the plurality of flows, the transmitting terminal receives an add schedule for transmitting an add frame in an add flow different from the plurality of flows,
determining 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 transmission periods of frames in each of the plurality of flows;
if it is determined that the first period is a divisor of the least common multiple, set the time slots for the plurality of communication devices to transmit the additional frames in the first period in the gate control list of each of them, and if it is determined that the first period is not a divisor of the least common multiple, set the time slots for the transmission of the additional frames in the gate control list of each of the plurality of communication devices, which is different from a last communication device that transmits the additional frame directly to the receiving terminal, in 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 when 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 when 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 Item 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 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.
[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 specified required delay.
[Additional Note 6]
The communication system described in Appendix 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 specified 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: 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 comprising:
The transmitting terminal receives an add schedule for transmitting an add frame in an add flow different from the plurality of flows, the transmitting terminal receives an add schedule for transmitting an add frame in an add flow different from the plurality of flows,
determining 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 transmission periods of frames in each of the plurality of flows;
if it is determined that the first period is a divisor of the least common multiple, set the time slots for the plurality of communication devices to transmit the additional frames in the first period in the gate control list of each of them, and if it is determined that the first period is not a divisor of the least common multiple, set the time slots for the transmission of the additional frames in the gate control list of each of the plurality of communication devices, which is different from a last communication device that transmits the additional frame directly to the receiving terminal, in 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.

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

The above-mentioned embodiments have been described as representative examples, but 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-mentioned embodiments, and various modifications or changes are possible without departing from the scope of the claims. For example, it is possible to combine multiple configuration blocks shown in the configuration diagram of the embodiment into one, or to divide one configuration block.

1. Transmitting terminal (Talker)
2. Receiving terminal (Listener)
3k Communication device 4 User management device 5, 5-1 Control device 100, 100-1 Communication system 501 CUC receiving port (user-set receiving port)
502 CUC port receiver (user-defined receiver)
503 GCL storage unit 504 Periodicity judgment unit 505, 505-1 GCL calculation unit 506 CUC transmission communication port (user-set transmission port)
507 CUC transmission unit (user setting transmission unit)
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 (8)

A communication system comprising: a transmitting terminal that transmits a delay-guaranteed frame; a plurality of communication devices that sequentially transfer the frame; a receiving terminal that receives the frame transferred by the plurality of communication devices; and a control device that controls the plurality of communication devices,
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 each of a plurality of flows;
a user setting receiving unit that receives an additional schedule for the transmitting terminal to transmit an additional frame 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 a least common multiple of the transmission periods of frames in each of the plurality of flows;
a gate control list calculation unit which, 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 in 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 each of the communication devices, which is different from a last communication device that directly transmits the additional frame to the receiving terminal, in the gate control list in a second period that is shorter than the first period and is a divisor of the least common multiple;
a communication device transmitter that transmits to the communication device a gate control list in which the time slots are set. The communication system according to claim 1, wherein the gate control list calculation unit, when it is determined that the first period is not a divisor of the least common multiple, sets the time slot in which the last communication device transmits the additional frame in the gate control list with the second period. The communication system of claim 1, wherein the gate control list calculation unit, when it is determined that the first period is not a divisor of the least common multiple, sets a time slot for the final communication device to transmit the additional frame in the gate control list with the first period. 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 additional 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. 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 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. 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 a queuing delay, and the given delay is shorter than a predetermined required delay. 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 an additional frame 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 transmission periods of frames in each of the plurality of flows;
a gate control list calculation unit which, 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 in 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 each of the communication devices, which is different from a last communication device that directly transmits the additional frame to the receiving terminal, in the gate control list in a second period that is shorter than the first period and is a divisor of the least common multiple;
a communication device transmitter that transmits to the communication device a gate control list in which the time slots are set;
A control device comprising: A program for causing a computer to function as the control device according to claim 7.

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