JP7795140B2 - Communication system, control device, and program - Google Patents

Description

The present 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 the communication device (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 are transmitted for each of the multiple flows. The communication device repeats frame transmission according to the GCL, allowing frames from multiple flows to 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 time slots for transmitting additional frames from additional flows to a GCL designed as described above, it may not be possible to represent the repetition of the transmission of the additional frames while maintaining the length of the existing GCL. Specifically, if the period for transmitting the additional frames is not a divisor of the least common multiple of the periods for transmitting frames in multiple flows shown in the existing GCL, it may not be possible to represent the repetition of the transmission of the additional frames while maintaining the length of the existing GCL. In such cases, it is necessary to design a GCL whose length is the least common multiple of the periods for transmitting frames in multiple flows shown in the existing GCL and the periods for transmitting the additional frames.

The GCL designed in this way is longer than existing GCLs, which increases the complexity of communication control, including scheduling. Furthermore, changing the length of the GCL requires shutting down the operating communication system, which in turn requires interrupting the services provided by the communication system.

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

In order to solve the above problem, the communication system according to the present disclosure is a communication system comprising: 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. 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 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.

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 forward 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 the 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 each of the plurality of flows; and 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 in 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, 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.

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

The communication system, control device, and program disclosed herein can prevent the complexity of communication control from increasing 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. 1 is a schematic diagram illustrating a queue and a gate. FIG. 1 is a schematic diagram showing an example of a GCL. 10A and 10B are diagrams illustrating an example of timing at which frames are transmitted in accordance with a GCL in which time slots are set by a control device according to the first embodiment. 4 is a flowchart illustrating an example of an operation of the control device according to the first embodiment. 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. 10 is a flowchart illustrating an example of an operation of a control device according to a 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, multiple communication devices 3k (k = an integer from 1 to n, n = an integer greater than or equal to 2 (in the example of Figure 1, n = 3)), a user management device 4, and a control device 5. The communication system 100 performs delay-guaranteed communication (ST (Scheduled Traffic) communication) 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.

Talker 1 transmits frames with a guaranteed delay. Specifically, Talker 1 transmits frames to Listener 2 via multiple communication devices 3k. In addition, when an additional schedule is added for transmitting frames (additional frames) through a new flow (additional flow), 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 then 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 transfer control using TAS.

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

The CUC receiving port 501, CUC transmitting port 506, and TSN-SW transmitting port 508 are configured by communication interfaces. The CUC port receiving unit 502, periodicity determining unit 504, GCL calculation unit 505, CUC port transmitting unit 507, and 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 FPGA (Field-Programmable Gate Array), a processor, or may include both. The GCL storage unit 503 is configured by memory. The memory may be an 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 memory unit 503 stores the GCL. The GCL is information indicating a schedule for each communication device 3k to transmit frames in each of multiple flows. Specifically, the GCL is information indicating a schedule (see Figure 4) for opening and closing each of multiple gates GT (see Figure 3) provided in the communication device 3k. As shown in Figure 3, when a gate GT is opened, the transmitting 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 by priority. Priority may be Class of Service (CoS) in Ethernet frames. The transmitting port of communication device 3k then 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, allowing frames held in queue QE with priority C7 to be 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), preventing frames held in queues QE with priorities C0 to C6 from being transmitted.

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" shown in Figure 4), and the gates GT corresponding to the queue QE with priorities C0 to C6 are closed ("c" shown 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.

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. Thus, when the time corresponding to time slots TS1 to TS5 has passed, the time again becomes time slot TS1 corresponding to the time, and this process 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 Figure 5. In Figure 5, the timing at which the gate GT is opened is indicated by a rectangle. In the example shown in Figure 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 Figure 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 communication device 3k with a second period prd2. Also, although not shown in Figure 5, time slots for transmitting frames for each of priorities C0 to C6 are set periodically in the same manner.

Furthermore, Figure 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 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 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.

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 sets the time slots for each of the multiple communication devices 3k to transmit additional frames in their respective GCLs at the first period prd1.

Furthermore, 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 respective GCLs at the second period prd2.Furthermore, 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 respective GCLs at the second period prd2.

The final communication device is communication device 3k that transmits a frame directly to Listener 2, i.e., 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 non-queuing E2E (End to End) delay is shorter than the specified required delay. The non-queuing E2E delay is the delay that occurs when additional frames are sent from Talker 1 to Listener 2 without any queuing delay. The non-queuing E2E delay includes at least the sum of the propagation delay. For example, when communication system 100 forwards frames using the cut-through method, the non-queuing E2E delay includes the propagation delay and the processing delay required for transmission control. For example, when communication system 100 forwards frames using the 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 specified required delay is the delay required when frames are sent from Talker 1 to Listener 2 and is determined by the contract with the user.

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 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 with the second period prd2. At this time, communication device 31 of communication device 3k may start transmitting the additional frame when queuing delay Dq has elapsed since receiving the additional frame from Talker 1. Furthermore, when communication device 3k, where k = 2 to n, receives an additional frame from communication device 3(k-1), it will transmit the additional frame without queuing delay.

Explaining in more detail with reference to the example shown in Figure 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 the reception of additional frame f2.

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

In this way, in the first embodiment, Listener 2 receives additional frames transmitted from Talker 1 at the first period prd1 at the second period prd2. As a result, jitter of a maximum length of 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 the nearest integer. Furthermore, a is a positive integer. Therefore, Listener 2 may perform any processing 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 also transmit information to the user management device 4 indicating that the last communication device will transmit frames to Listener 2 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 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 to the communication device 3k a GCL for which a time slot has been set by the GCL calculation unit 505 as described above.

<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 receiving unit 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 to their respective GCLs at the first period prd1.

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 to the respective GCLs at the second period 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 to the GCL at 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 to the GCL at the second period prd2.

In step S15, the TSN-SW port transmitting 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, multiple communication devices 3k that sequentially forward the frames, a Listener 2 that receives the frames forwarded by the multiple communication devices 3k, and a control device 5 that controls the multiple 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 multiple flows. The control device 5 also includes a CUC port receiver 502 that receives an additional schedule for Talker 1 to transmit additional frames in an additional flow that is different from the multiple 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 frame transmission periods of each of the multiple flows. The control device 5 also includes a GCL calculation unit 505 that, if it is determined that the first period prd1 is a divisor of the least common multiple h_prd, sets a time slot for each of the multiple communication devices 3k to transmit an additional frame at the first period prd1 in the GCL, and, if it is determined that the first period prd1 is not a divisor of the least common multiple h_prd, sets a time slot for each of the multiple communication devices 3k (k = 1 to n-1) that is different from the last communication device that transmits a frame directly to the Listener 2 to transmit an additional frame at a second period prd2 that is shorter than the first period 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 slot is set to the communication device 3k.

As a result, when an additional flow is added, communication system 100 can set a time slot for transmitting additional frames in that flow without changing the length of the GCL. This prevents the complexity of communication control from increasing and avoids service interruptions.

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 the 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 and avoid service interruptions while maintaining communication quality.

<<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 Figure 1, the communication system 100-1 includes a Talker 1, a Listener 2, multiple communication devices 3k, and a user management device 4. In addition, the communication system 100-1 includes a control device 5-1 instead of the control device 5 shown in Figure 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. Similar to the control device 5 shown in Fig. 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. The control device 5-1 also includes a GCL calculation unit 505-1 instead of the GCL calculation unit 505 shown in Fig. 2. Similar to the control device 5, the control device 5-1 is, for example, a CUC.

The GCL calculation unit 505-1 is composed of 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 their respective GCLs at the first period prd1.

Similar to the GCL calculation unit 505 of the first embodiment, when 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 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.

As in 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 the specified 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 specified required delay.

Furthermore, 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 additional 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 in the additional flow when the added delay d_add has elapsed since receiving the first additional frame 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.

Explaining in more detail with reference to the example shown in Figure 7, 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. Also, 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 in the subsequent time slot.

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

Furthermore, communication device 33 receives additional frame f1 when propagation delay Dp has elapsed since communication device 32 started transmitting additional frame f1, and transmits additional frame f1 when added delay d_add has elapsed since receiving additional frame f1.Furthermore, communication device 33 receives additional frames f2 to f4 when propagation delay Dp has elapsed since communication device 32 started transmitting additional frames f2 to f4, respectively, and transmits additional frames f2 to f4 at the first period 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 communication device 3k to transmit frames in each of a plurality of flows.

The operations of steps S21 to S23 are the same as the operations of steps S11 to 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 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 at 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 a time slot for the final communication device (communication device 3n) to transmit an additional frame in the GCL at the first period prd1. At this time, the GCL calculation unit 505-1 sets a 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 additional 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 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 additional frames to the GCL at the first period prd1. This allows the communication system 100-1 to continue to realize deterministic periodic communication in which Listener 2 receives additional frames at the same period as 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 the specified required delay. This allows the communication system 100-1 to set a time slot for transmitting additional frames in the flow without changing the specified 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 and avoid service interruptions while maintaining communication quality.

<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.

As shown in FIG. 9, computer 601 includes processor 610, ROM (Read Only Memory) 620, RAM (Random Access Memory) 630, storage 640, input unit 650, output unit 660, and communication interface (I/F) 670. Each component is communicatively connected to one another via bus 680. Processor 610 is specifically 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 performs various arithmetic operations. That is, processor 610 reads a program from ROM 620 or storage 640 and executes the program using RAM 630 as a work area. Processor 610 controls each component and performs various arithmetic operations in accordance with 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 on a storage medium readable by computer 601. Using such a storage medium, the program can be installed on computer 601. Here, the storage medium on which the program is stored may be a non-transitory storage medium. Non-transitory storage media are not particularly limited, but may be, for example, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory. The program may also be 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 an 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 user input operations 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.

The output unit 660 includes one or more output interfaces that output information. For example, the output unit 660 may be, but is not limited to, a display that outputs information visually or a speaker that outputs information audibly. Note that if the output unit 660 is a touch panel 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 disclosed regarding the above embodiments.

[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 frame 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 multiple communication devices set the time slots for transmitting the additional frames 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 multiple communication devices, other than the last communication device that directly transmits the additional frames to the receiving terminal, set the time slots for transmitting the additional frames to the gate control lists to 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 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 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 predetermined 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 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 frame 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 multiple communication devices set the time slots for transmitting the additional frames 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 multiple communication devices, other than the last communication device that directly transmits the additional frames to the receiving terminal, set the time slots for transmitting the additional frames to the gate control lists to 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 mentioned in this specification are incorporated by reference herein 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-described embodiments have been described as representative examples, but it will be apparent to those skilled in the art that numerous modifications and substitutions are possible within the spirit and scope of the present disclosure. Therefore, the present invention should not be construed as being limited to the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the claims. For example, it is possible to combine multiple building blocks shown in the configuration diagrams of the embodiments into one, or to divide one building 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 setting receiving port)
502 CUC port receiver (user-defined receiver)
503 GCL storage unit 504 Periodicity determination 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 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. The communication system described in claim 1, wherein the gate control list calculation unit, when it determines 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 at the second period. The communication system described in claim 1, wherein the gate control list calculation unit, when it determines that the first period is not a divisor of the least common multiple, sets a time slot for the last communication device to transmit the additional frame in the gate control list at 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 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. The communication system described in 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 described in 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 specified 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 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: A program for causing a computer to function as the control device according to claim 7.