WO2024166398A1

WO2024166398A1 - Control device, control method, and control program

Info

Publication number: WO2024166398A1
Application number: PCT/JP2023/004661
Authority: WO
Inventors: 佳紀青木; 貴允鳴海; 孝幸中村
Original assignee: 日本電信電話株式会社
Priority date: 2023-02-10
Filing date: 2023-02-10
Publication date: 2024-08-15

Abstract

A controller (200) includes a determination unit (222) and a setting unit (223). The determination unit (222) determines, on the basis of acquired information, in a case in which a new priority flow is to be added, at least one of a route for the new priority flow and a transmission timing and a route for a non-priority flow and determines, in a case in which a flow for a new non-priority packet is to be added, a route for the new non-priority flow and the route for the non-priority flow. Moreover, the setting unit (223) sets the route for the flow determined by the determination unit (222) and the like to a transmission terminal or a transfer device.

Description

Control device, control method, and control program

The present invention relates to a control device, a control method, and a control program.

In a 5G environment, there are cases where packets with various QoS (Quality of Service) requirements are transferred within a single network slice. Priority packets that require real-time performance, such as for controlling a robot in a remote location, are transferred with priority over other non-priority packets that do not require real-time performance in order to guarantee communication delays and delay fluctuations (jitter).

In order to guarantee the delay fluctuation value of the flow of priority packets (priority flow), there is a function called TAS (Time Aware Shaper) defined in IEEE 802.1Qbv. TAS proposes a method to reduce the queuing delay of priority packets by blocking the gate for non-priority packets in advance in the time slot in which the periodically transmitted priority packets arrive at the forwarding device (see, for example, Patent Document 1).

JP 2018-129661 A

However, conventional technology may not be able to increase the number of flows that can be accommodated in a network, including flows of non-priority packets (non-priority flows). For example, when using TAS, the timing at which each transfer device blocks a non-priority gate can be synchronized, but no control is implemented over the communication path or transmission timing of the priority traffic that flows. Therefore, there is a possibility that a concentration of priority packets will arrive at a specific time, causing the priority packet queue to overflow, or that priority packets will arrive at various times, causing non-priority gates to continue to be blocked, significantly impacting the non-priority packets.

　Network slice users can reduce slice usage fees by minimizing the network resources they use, but they will need control to ensure that fewer resources can accommodate the number of priority flows.

Furthermore, in conventional technology, there were cases where only the number of priority flows that could be accommodated in the network increased, and the number of non-priority flows that could be accommodated in the network did not increase. For example, in conventional technology, when priority flows were accommodated in a TAS network, the priority flows were optimized, but for non-priority flows, the gate opening time was only guaranteed, and the total number of flows that could be accommodated was not maximized.

Here, while the route of a non-priority flow can be changed by rearrangement, a priority flow, although it is best effort, needs to occupy resources to secure bandwidth to meet strict delay fluctuation requirements, and it may not be possible to change the route. For this reason, for example, it may be possible to increase the amount of resources available to a non-priority flow by reducing the resources occupied by the priority flow, but with conventional technology, it was sometimes impossible to increase the amount of resources available to a non-priority flow unless the resources occupied by the priority flow could be reduced.

In particular, when there are existing non-priority flows that have already been accommodated or when accommodating new non-priority flows, it is necessary to consider optimizing the accommodation of all flows while taking into account improvements to the accommodation efficiency of non-priority flows; however, conventional technology did not take into account the optimization of the accommodation of non-priority flows. As a result, conventional technology sometimes did not maximize the number of flows that can be accommodated in a network, including non-priority flows. Also, when a flow is discontinued or deleted, the number of flows that can be accommodated in a network, including non-priority flows, is not optimized, which could result in the use of unnecessary resources.

The present invention was made in consideration of the above-mentioned problems, and aims to increase the number of flows, including non-priority flows, that can be accommodated in a network.

In order to solve the above problems and achieve the object, the control device is characterized by having an acquisition unit that acquires topology information indicating the connection form of the network and information on the forwarding delay of each forwarding device that forwards priority packets and non-priority packets, a determination unit that, when a new priority packet flow is added, determines at least one of the path and transmission timing of the new priority packet flow and the path of the non-priority packet flow based on the topology information and the forwarding delay information of each forwarding device acquired by the acquisition unit, and, when a new non-priority packet flow is added, determines the path of the new non-priority packet flow and the path of the non-priority packet flow based on the topology information and the forwarding delay information of each forwarding device acquired by the acquisition unit, and a setting unit that sets the path and transmission timing of the new priority packet flow and the path of the non-priority packet flow determined by the determination unit, or the path of the new non-priority packet flow and the path of the non-priority packet flow, to the forwarding device or the transmitting terminal.

The present invention makes it possible to increase the number of flows that can be accommodated in a network, including non-priority flows.

FIG. 1 is a diagram illustrating an example of the configuration of a control system according to the first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the control device according to the first embodiment. FIG. 3 illustrates an example of a flow addition procedure according to the first embodiment. FIG. 4 illustrates an example of a flow addition procedure according to the first embodiment. FIG. 5 is a diagram illustrating an example of adding a flow according to the first embodiment. FIG. 6 is a diagram illustrating an example of adding a flow according to the first embodiment. FIG. 7 is a flowchart illustrating an example of a flow addition according to the first embodiment. FIG. 8 is a flowchart illustrating an example of a flow addition according to the first embodiment. FIG. 9 is a diagram illustrating an example of the configuration of a control system according to the second embodiment. FIG. 10 is a diagram illustrating an example of the configuration of the control device according to the second embodiment. FIG. 11 illustrates an example of a flow deletion procedure according to the second embodiment. FIG. 12 illustrates an example of a flow deletion procedure according to the second embodiment. FIG. 13 is a diagram illustrating an example of flow deletion according to the second embodiment. FIG. 14 is a diagram illustrating an example of flow deletion according to the second embodiment. FIG. 15 is a flowchart illustrating an example of flow deletion according to the second embodiment. FIG. 16 is a flowchart illustrating an example of flow deletion according to the second embodiment. FIG. 17 is a diagram illustrating a computer that executes a control program according to the embodiment.

Below, one embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, in the description of the drawings, the same parts are indicated by the same reference numerals, and duplicate explanations will be omitted.

First Embodiment
A first embodiment will be described below. In the first embodiment, a case will be described in which, when a new priority flow is added, a new priority flow and a non-priority flow are optimized, and, when a new non-priority flow is added, all non-priority flows are optimized.

[1. Example of control system configuration]
First, the configuration of the control system 1 will be described with reference to Fig. 1. Fig. 1 is a diagram illustrating an example of the configuration of the control system 1 according to the first embodiment. The system illustrated in Fig. 1 includes a transmitting terminal 10, a controller (control device) 200, an orchestrator 30, and a transfer device 40. The control system 1 may be realized by a plurality of devices. In addition, when the control system 1 is realized by a plurality of devices, each component of the control system 1 may be allocated to the plurality of devices in any manner.

First, the transmitting terminal 10 makes a request to the controller 200 to add a new flow of priority packets (new priority flow) or a new flow of non-priority packets (new non-priority flow). The transmitting terminal 10 also transmits a request to add a new flow in accordance with the transmission timing setting received from the controller 200. Next, the controller 200 performs calculations in response to the request to add a new flow from the transmitting terminal 10. If the result of the calculation shows that there are insufficient network resources (resources), the controller 200 requests the orchestrator 30 to add resources. The controller 200 also sets flow control for the transmitting terminal 10 or the transfer device 40. Details of the controller 200 will be described later.

The orchestrator 30 is an external device that manages slices. In addition, the orchestrator 30 adds resources in response to a resource addition request from the controller 200. In addition, there are multiple transfer devices 40 on the network, and in response to a flow transmitted from the transmitting terminal 10, the transfer device 40 transfers the flow.

[2. Controller configuration example]
Next, the configuration of the controller 200 will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the configuration of the controller 200 according to the first embodiment. As shown in Fig. 2, the controller 200 includes a communication unit 210, a control unit 220, and a storage unit 230. Each of these units may be held in a distributed manner in a plurality of devices. The processing of each of these units will be described below.

The communication unit 210 is realized by a NIC (Network Interface Card) or the like, and enables communication between the control unit 220 and external devices via telecommunication lines such as a LAN (Local Area Network) or the Internet. For example, the communication unit 210 enables communication between the control unit 220 and the transfer device 40 or external devices.

The storage unit 230 is realized by a semiconductor memory element such as a random access memory (RAM) or a flash memory, or a storage device such as a hard disk or an optical disk. Here, the storage unit 230 has a network topology storage unit 231 and an accommodation flow storage unit 232.

The NW topology storage unit 231 stores topology information, which is configuration information of the network, as well as information on the delay time, maximum flow rate, and minimum open time of non-priority gates of each transfer device 40. The accommodated flow storage unit 232 stores information on the target delay time, source node, and destination node of flows that have already been accommodated. Note that the above content is an example, and the items stored in the NW topology storage unit 231 and the accommodated flow storage unit 232 are not limited to those listed here.

The control unit 220 is realized using a CPU (Central Processing Unit), NP (Network Processor), FPGA (Field Programmable Gate Array), etc., and executes processing programs stored in memory. As a result, the control unit 220 functions as an acquisition unit 221, a determination unit 222, a setting unit 223, a resource request unit 224, and a topology update reception unit 225. Note that each of these functional units may be implemented in different hardware. The control unit 220 may also include other functional units.

The acquisition unit 221 acquires topology information indicating the connection form of the network and information on the forwarding delay of each forwarding device that forwards priority packets and non-priority packets. The acquisition unit 221 may further acquire information on the minimum opening time of the non-priority gate in each forwarding device. For example, the acquisition unit 221 acquires topology information indicating the connection form of the network, the forwarding delay of the forwarding device 40, the maximum flow rate, and the minimum opening time of the non-priority gate from the NW topology storage unit 231. The acquisition unit 221 also acquires the target delay time of the accommodated flow and information on the source node and destination node from the accommodated flow storage unit 232. When a request to add a new flow is made from the transmitting terminal 10, the acquisition unit 221 acquires information on the source node, destination node, and target delay time of the new flow from the transmitting terminal 10. The acquisition unit 221 may also acquire information on the bandwidth of each link between each forwarding device 40.

The determination unit 222 determines the path and transmission timing of the flow based on the topology information acquired by the acquisition unit 221 and the information on the forwarding delay of each transfer device 40. Specifically, when a new priority flow is added, the determination unit 222 determines at least one of the path and transmission timing of the new priority flow and the path of the non-priority flow based on the topology information acquired by the acquisition unit 221 and the information on the forwarding delay of each transfer device 40. In addition, when a new non-priority flow is added, the determination unit 222 determines the path of the new non-priority flow and the path of the non-priority flow based on the topology information acquired by the acquisition unit 221 and the information on the forwarding delay of each transfer device 40.

The following describes in detail the configuration in which the determination unit 222 determines the path and transmission timing of a new priority flow when a new priority flow is added. In this case, based on the topology information acquired by the acquisition unit 221 and information on the transfer delay of each transfer device 40 and the minimum opening time of a non-priority gate, the determination unit 222 may determine the path and transmission timing of a new priority flow such that the delay time until the new priority flow is transmitted from the source node to the destination node is within a target delay time preset for each new priority flow and the time that the non-priority gate is open is equal to or longer than the minimum opening time set for the non-priority gate.

For example, the determination unit 222 determines at least one of the path and transmission timing of the new priority flow based on the information stored in the storage unit 230 and the information notified from the transmitting terminal 10. Here, the transmission timing refers to the timing at which the transfer device 40 transfers the new priority flow. In addition, the transmission timing is not limited to the above example, and may be the timing at which the transmitting terminal 10 transmits the new priority flow.

The following describes the specific process of determining the route and transmission timing of the new priority flow by the determination unit 222 when a new priority flow is added. For example, the determination unit 222 determines the route and transmission timing of the new priority flow based on topology information indicating the network connection form held by the NW topology storage unit 231, information on the transfer delay of the transfer device 40 and the minimum opening time of the non-priority gate, and information on the source node, destination node, and target delay time of the new priority flow notified from the transmitting terminal 10, so that the delay time until the new priority flow is transferred from the source node to the destination node is within the target time of the new priority flow and the same transfer device 40 is not transferred more than its capacity in the same period.

In this case, the decision unit 222 may use the optimal solution that is the result of the calculation by the linear programming problem solver to calculate the route and transmission timing of the new priority flow. For example, the decision unit 222 formulates a linear programming problem using the following objective function (i) or the like based on topology information, information on the transfer delay of the transfer device 40 and the minimum opening time of the non-priority gate, and information on the source node, destination node, and target delay time of the new priority flow notified from the transmitting terminal 10, and passes it to the linear programming problem solver and accepts the return of the variable results.

The objective function (i) of the linear programming problem is set to, for example, minimize the blocking time of non-priority gates at the node, minimize priority packets that do not satisfy QoS, and minimize the blocking time of non-priority gates at the node in all time slots, as shown in the following formula (1).

In the above formula (1), K represents the set of all priority packets. T represents the set of all time slots. V represents the set of all network nodes. close _v represents a binary variable to which 1 is assigned if the non-priority gate of node v is closed in time slot t. δ represents a sufficiently small value for the first term. pBlock _k represents a binary variable to which 1 is assigned if priority flow k does not satisfy QoS (Quality of Service). ε represents a sufficiently small value for the second term. close _v,t represents a binary variable to which 1 is assigned if the non-priority gate of node v is closed in time slot t.

The pre-held parameters are the topology, the forwarding delay of each forwarding device 40, the maximum flow rate of each link between each forwarding device 40, and the minimum opening time of the non-priority gate at each node. The determination unit 222 determines the route and transmission timing of the new priority flow by obtaining a real solution using the target delay time information, which is a parameter of the existing priority flow that has already been accommodated, the departure node and arrival node as constants, and the route and transmission timing of the additional priority flow as variables.

Next, a specific process for determining the route of a non-priority flow by the determination unit 222 when a new priority flow is added will be described. For example, if the acquisition unit 221 has acquired bandwidth information of each link between each transfer device 40, the determination unit 222 may determine the route of the non-priority flow based on the bandwidth information acquired by the acquisition unit 221.

In this case, the decision unit 222 may use the optimal solution that is the result of the calculation by the linear programming problem solver to calculate the route of the non-priority flow. For example, the decision unit 222 formulates a linear programming problem using the following objective function (ii) or the like based on topology information, information on the forwarding delay of the forwarding device 40, information on the source node, destination node, and target delay time of the new priority flow notified from the transmitting terminal 10, and information on the bandwidth of each link between each forwarding device 40, passes the problem to the linear programming problem solver, and accepts the return of the variable results.

The objective function (ii) of the linear programming problem is set to, for example, minimize non-priority packets that do not satisfy the QoS and minimize the maximum bandwidth of each link between each transfer device 40, as shown in the following formula (2).

In the above formula (2), K represents the set of all priority packets. E represents the set of all links. bBlock _k represents a binary variable that is set to 1 if non-priority flow K does not satisfy the QoS. δ represents a sufficiently small value for the first term. _{Bandwidth i,j} represents the bandwidth used on the link from node i to node j.

The pre-held parameters are the topology, the forwarding delay of each forwarding device 40, the maximum flow rate of each link between each forwarding device 40, and the accommodation status of each priority flow. The determination unit 222 determines the route of the non-priority flow by obtaining a real solution using the target delay time information, which is the parameter of all non-priority flows, and the departure node and arrival node as variables.

The above example describes the specific process of determining the routes of non-priority flows by the determination unit 222 when a new priority flow is added, and therefore the non-priority flow does not include the new non-priority flow. In contrast, when a new non-priority flow is added, the determination unit 222 determines the routes of all non-priority flows in the same manner as when a new priority flow is added, except that the determination unit 222 determines the routes of all non-priority flows including the new non-priority flow in addition to the existing non-priority flows that have already been accommodated. In other words, when a new non-priority flow is added, the determination unit 222 determines the routes of the non-priority flows in the same manner as the above example, except that the determination unit 222 determines the routes of all non-priority flows including the new non-priority flow in addition to the routes of the existing non-priority flows.

The setting unit 223 sets the path and transmission timing of the flow determined by the determination unit 222 to the transfer device 40 or the transmitting terminal 10. Specifically, the setting unit 223 sets at least one of the path and transmission timing of the new priority flow determined by the determination unit 222 and the path of the non-priority flow, or the path of the new non-priority flow and the path of the non-priority flow to the transfer device 40 or the transmitting terminal 10. Furthermore, when the transmission timing of the new priority flow is determined by the determination unit 222, the setting unit 223 sets the timing of transferring the flow of the transfer device 40 as the transmission timing determined by the determination unit 222. Furthermore, the setting unit 223 sets the timing of transmitting the flow of the transmitting terminal 10 as the transmission timing determined by the determination unit 222.

When the flow route of the non-priority packets is determined by the determination unit 222, if the non-priority packets do not satisfy the QoS, the resource request unit 224 requests an increase in the bandwidth of the link between each transfer device 40 whose flow rate exceeds the maximum flow rate of each transfer device 40.

If the resource request unit 224 is unable to determine a flow path or transmission timing that satisfies the calculation results of the determination unit 222, such that the delay time until the flow is transmitted from the source node to the destination node is within the target delay time preset for each flow and the time that the non-priority gate is open is equal to or longer than the minimum open time set for the non-priority gate, the resource request unit 224 may request additional resources from an external device. Here, an example of an external device to which the resource request unit 224 requests additional resources is the orchestrator 30.

Also, for example, the resource request unit 224 requests an external device to add resources necessary to determine the flow path and transmission timing such that the delay time until the flow is transmitted from the source node to the destination node is within a target delay time preset for each flow, and the time that a non-priority gate is open is equal to or longer than the minimum open time set for the non-priority gate.

The topology update reception unit 225 receives updates to topology information indicating the connection form of the network and stores it in the NW topology storage unit 231. For example, when a new priority flow or a new non-priority flow is added and the connection form of the network is changed, the topology update reception unit 225 receives notification of the topology update and stores the new topology information by storing it in the NW topology storage unit 231.

[3. Flow Addition Procedure]
Next, a procedure (flow addition procedure) up to transfer of a flow when a new flow is added by the control system 1 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 and Fig. 4 are diagrams showing an example of a flow addition procedure by the control system 1 according to the first embodiment.

First, the flow addition procedure when a new priority flow is added will be described with reference to FIG. 3. As shown in FIG. 3, the control system 1 of this embodiment includes a transmitting terminal 10, a controller 200, an orchestrator 30, and a forwarding device 40.

First, the transmitting terminal 10 requests the controller 200 to add a new priority flow (1). In this case, the transmitting terminal 10 notifies the controller 200 of information on the source node, destination node, and target delay of the new priority flow to be added. Next, the controller 200 determines the route and transmission timing of the new priority flow and the route of the non-priority flow based on the source node, destination node, target delay information, topology information, and forwarding delay information of the forwarding device 40 of the new priority flow notified by the transmitting terminal 10 (2). If the controller 200 cannot determine the route and transmission timing of the new priority flow or the route of the non-priority flow, it determines that there are insufficient resources and requests the orchestrator 30 to add a minimum number of resources, such as pre-specified links (3).

Next, the orchestrator 30, which has received a request from the controller 200 to add the minimum number of resources, performs the resource addition process (4). After that, the orchestrator 30 notifies the controller 200 that the resource addition process has been successfully performed (5).

The controller 200 then sets the determined path and transmission timing of the new priority flow and the path of the non-priority flow in the transfer device 40 (6). As a result, the path and transmission timing of the new priority flow and the path of the non-priority flow are set in the transfer device 40 (7). Next, the transfer device 40 notifies the controller 200 that the path and transmission timing of the new priority flow and the path of the non-priority flow have been set successfully (8). Next, the controller 200 sets the transmission timing of the new priority flow in the transmitting terminal 10 and permits it to start transmitting (9). Then, the transmitting terminal 10 starts transmitting the new priority flow (10).

In the above example, the controller 200 determines both the path and the transmission timing of the new priority flow, but it is sufficient to determine at least one of the path and the transmission timing of the new priority flow. For example, the controller 200 may determine only one of the path and the transmission timing of the new priority flow, i.e., the path or the transmission timing of the new priority flow. In either case, it is possible to increase the number of flows that can be accommodated in the network.

Next, the flow addition procedure when a new non-priority flow is added will be described with reference to FIG. 4. As in FIG. 3, the control system 1 of this embodiment includes a transmitting terminal 10, a controller 200, an orchestrator 30, and a forwarding device 40.

First, the transmitting terminal 10 requests the controller 200 to add a new non-priority flow (11). In this case, the transmitting terminal 10 notifies the controller 200 of information on the source node, destination node, and target delay of the new non-priority flow that is requested to be added. Next, the controller 200 determines the route of the new non-priority flow and the route of the non-priority flow (routes of all non-priority flows) based on the source node, destination node, and target delay information of the new non-priority flow notified by the transmitting terminal 10, topology information, and forwarding delay information of the forwarding device 40 (12). If the controller 200 cannot determine the route of the new non-priority flow and the route of the non-priority flow, it determines that there is a resource shortage, and requests the orchestrator 30 to add a minimum amount of resources, such as pre-specified links (13).

Next, the orchestrator 30, which has received a request from the controller 200 to add the minimum number of resources, performs the resource addition process (14). After that, the orchestrator 30 notifies the controller 200 that the resource addition process has been successfully performed (15).

The controller 200 then sets the determined new non-priority flow path and non-priority flow path in the transfer device 40 (16). As a result, the new non-priority flow path and non-priority flow path are set in the transfer device 40 (17). Next, the transfer device 40 notifies the controller 200 that the new non-priority flow path and non-priority flow path have been set successfully (18). Next, the controller 200 permits the transmitting terminal 10 to start transmission (19). Then, the transmitting terminal 10 starts transmitting the new non-priority flow (20).

[4. Add flow]
Next, an example of flow control (flow addition) by path setting when a new flow is added will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are diagrams showing an example of flow addition by the control system 1 according to the first embodiment.

First, an example of flow addition when a new priority flow is added will be described using FIG. 5. FIG. 5 (1) shows a flow for which no route is set, and FIG. 5 (1) shows non-priority flows (i) and (ii), a priority flow, a new priority flow, and the delay time for each link between each transfer device 40.

In Figure 5 (1), at the location marked with an x, the path of the non-priority flow (ii), the path of the priority flow, and the path of the non-priority flow overlap, which may cause traffic collisions. In this case, if the total amount of colliding traffic exceeds the maximum flow rate of the forwarding device 40, congestion will occur, and at the above-mentioned location, there may be no available time slots for priority packets of a new priority flow to arrive at the forwarding device 40.

On the other hand, FIG. 5 (2) shows a flow controlled by route setting. Here, the controller 200 performs flow control, sets routes for the new priority flow and non-priority flows (i) and (ii), and modifies the routes of the non-priority flows (i) and (ii) by rearranging them. In this way, the controller 200 eliminates overlap between the route for the non-priority flow (ii), the route for the priority flow, and the route for the new priority flow.

Specifically, first, the controller 200 performs optimization calculation (i) to calculate the route and transmission timing of a new priority flow that ensures the minimum opening time of each non-priority gate and minimizes the blocking time of the non-priority gate while avoiding congestion. Next, the controller 200 performs optimization calculation (ii) to calculate the route of the non-priority flow that minimizes the number of non-priority packets that do not satisfy the QoS and minimizes the maximum bandwidth of each link between each transfer device 40.

Then, the controller 200 sets the route of the new priority flow obtained by the optimization calculation (i) for the forwarding device 40, thereby forwarding the new priority flow from the source node to the destination node within the target delay time. In this way, the controller 200 ensures the minimum opening time of the non-priority gates by reducing the load on the forwarding device 40, and maximizes the flow forwarding efficiency. By setting the route of the non-priority flow obtained by the optimization calculation (ii) for the forwarding device 40 in addition to the route of the new priority flow, the controller 200 avoids congestion that occurs when the total amount of colliding traffic exceeds the maximum flow rate of the forwarding device 40. In addition, this causes the controller 200 to increase the number of flows, including non-priority flows, that can be accommodated in the network.

Next, an example of flow addition when a new non-priority flow is added will be described with reference to FIG. 6. FIG. 6 (1) shows a flow for which no route is set, and FIG. 6 (1) shows a non-priority flow, a new non-priority flow, priority flows (i) and (ii), and the delay time for each link between each transfer device 40.

In Figure 6 (1), at the locations marked with an x, the route of the new non-priority flow, the route of the priority flow (i), and the route of the priority flow (ii) overlap, which can cause traffic collisions, congestion, and a lack of time slots.

On the other hand, FIG. 6 (2) shows a flow controlled by route setting. Here, the controller 200 performs flow control, sets routes for the non-priority flow and the new non-priority flow, and modifies the routes of the non-priority flows (i) and (ii) by rearranging them. In this way, the controller 200 eliminates overlap between the route of the new non-priority flow, the route of the priority flow (i), and the route of the priority flow (ii).

Specifically, the controller 200 performs an optimization calculation (ii) to calculate a route for a non-priority flow that minimizes non-priority packets that do not satisfy the QoS and minimizes the maximum bandwidth of each link between each transfer device 40. The controller 200 then sets the route for the non-priority flow obtained by the optimization calculation (ii) for the transfer device 40, thereby avoiding congestion that occurs when the total amount of colliding traffic exceeds the maximum flow rate of the transfer device 40. This also causes the controller 200 to increase the number of flows, including non-priority flows, that can be accommodated in the network.

5. Flowchart
A flow of flow control (flow addition) by path setting of the controller 200 according to the first embodiment when a new flow is added will be described with reference to Fig. 7 and Fig. 8. Fig. 7 and Fig. 8 are flowcharts showing an example of the flow of flow addition according to the first embodiment.

First, the flow of flow addition when a new priority flow is added will be described with reference to FIG. 7. First, the decision unit 222 of the controller 200 performs optimization calculation (i) with the existing flow as a constant and the added priority flow as a variable (step S101). Specifically, the decision unit 222 performs optimization calculation (i) with the path and transmission timing of the existing flow as constants and the path and transmission timing of the added priority flow as variables, to minimize the blocking time of non-priority gates while ensuring the minimum opening time of each non-priority gate and avoiding congestion.

Next, the resource request unit 224 of the controller 200 determines whether the optimal variable satisfies the following formula (3) based on the result of the calculation by the decision unit 222 (step S102). Here, if the optimal variable does not satisfy the following formula (3) (step S102 "No"), it means that there is a resource shortage. On the other hand, if the optimal variable satisfies the following formula (3) (step S102 "Yes"), it means that there is no resource shortage.

Here, if the resource request unit 224 determines that the optimal variables do not satisfy the following formula (3) (step S102 "No"), it requests the addition of bandwidth to the transfer device 40 whose flow rate exceeds the maximum flow rate with the optimal variables (step S103). In other words, when the route for a new priority flow is determined by the determination unit 222, if the new priority packet does not satisfy the QoS, the resource request unit 224 requests an increase in the bandwidth of the link between each transfer device 40 whose flow rate exceeds the maximum flow rate of each transfer device 40.

If the optimization variables satisfy the above formula (3) (step S102 "Yes"), or after completing the processing of step S103, the decision unit 222 performs optimization calculation (ii) for the non-priority flows with objective function (ii) using all non-priority flows as variables (step S104). Specifically, the decision unit 222 performs optimization calculation (ii) for calculating the route of the non-priority flows that minimizes non-priority packets that do not satisfy QoS and minimizes the maximum bandwidth of each link between each transfer device 40 using all non-priority flows as variables.

The resource request unit 224 determines whether the optimal variables satisfy the following formula (4) based on the calculation results by the determination unit 222 (step S105). Here, if the optimal variables do not satisfy the following formula (4) (step S105 "No"), this means that there is a resource shortage. On the other hand, if the optimal variables satisfy the following formula (4) (step S105 "Yes"), this means that there is no resource shortage.

Here, if the resource request unit 224 determines that the optimal variables do not satisfy the following formula (4) (step S105 "No"), it requests the addition of bandwidth to the transfer device 40 whose flow rate exceeds the maximum flow rate with the optimal variables (step S106). In other words, when the route for a non-priority flow is determined by the determination unit 222, if the non-priority packets do not satisfy the QoS, the resource request unit 224 requests an increase in the bandwidth of the link between each transfer device 40 whose flow rate exceeds the maximum flow rate of each transfer device 40.

If the optimal variables satisfy the above formula (4) (step S105 "Yes"), or if the processing of step S106 is completed, the setting unit 223 sets the route and transmission timing of the new priority flow and the route of the non-priority flow determined by the decision unit 222. Specifically, the setting unit 223 sets the route and transmission timing of the new priority flow with the optimal variables of the optimization calculation (i) and the route of the non-priority flow with the optimal variables of the optimization calculation (ii) for the transfer device 40 or the sending terminal 10, and transfers the flow (step S107).

Next, the flow of flow addition when a new non-priority flow is added will be described with reference to FIG. 8. First, the decision unit 222 performs an optimization calculation (ii) of the non-priority flow with the objective function (ii) using the new non-priority flow and existing non-priority flows (all non-priority flows) as variables (step S111). Specifically, the decision unit 222 performs an optimization calculation (ii) that uses all non-priority flows as variables to minimize non-priority packets that do not satisfy the QoS and calculates a route for the non-priority flow that minimizes the maximum bandwidth of each link between each transfer device 40.

The resource request unit 224 determines whether the optimal variables satisfy the above formula (4) as a result of the calculation by the determination unit 222 (step S112). If the resource request unit 224 determines that the optimal variables do not satisfy the following formula (4) (step S112 "No"), the resource request unit 224 requests the addition of bandwidth to the transfer device 40 whose optimal variables exceed the maximum flow rate (step S113). In other words, when the route of a non-priority flow is determined by the determination unit 222, if the non-priority packets do not satisfy the QoS, the resource request unit 224 requests an increase in the bandwidth of the link between each transfer device 40 whose flow rate exceeds the maximum flow rate of each transfer device 40.

If the optimal variables satisfy the above formula (4) (step S112 "Yes"), or if the processing of step S112 is completed, the setting unit 223 sets the route of the new non-priority flow and the route of the non-priority flow determined by the determination unit 222. Specifically, the setting unit 223 sets routes for all non-priority flows for the optimal variables of the optimization calculation (ii) for the transfer device 40 or the sending terminal 10, and transfers the flows (step S114).

6. Effects of the First Embodiment
As described above, the controller 200 according to the first embodiment includes an acquisition unit 221, a determination unit 222, and a setting unit 223. The acquisition unit 221 acquires topology information indicating the connection form of the network and information on the transfer delay of each transfer device 40 that transfers the priority packet and the non-priority packet. When a new priority packet flow is added, the determination unit 222 determines at least one of the path and transmission timing of the new priority packet flow and the path of the non-priority packet flow based on the topology information acquired by the acquisition unit 221 and the information on the transfer delay of each transfer device 40. When a new non-priority packet flow is added, the determination unit 222 determines the path of the new non-priority packet flow and the path of the non-priority packet flow based on the topology information acquired by the acquisition unit 221 and the information on the transfer delay of each transfer device 40. The setting unit 223 sets at least one of the flow path and transmission timing of new priority packets and the flow path of non-priority packets, or the flow path of new non-priority packets and the flow path of non-priority packets, determined by the determination unit 222, to the transfer device 40 or the transmitting terminal 10.

As a result, the controller 200 according to the first embodiment can increase the number of flows, including non-priority flows, that can be accommodated in the network based on the acquired information. Specifically, when a new priority flow is added, the controller 200 uses the collected information to set at least one of the route and transmission timing of the new priority flow, and the route of the non-priority flow, for the transmitting terminal 10 or the transfer device 40. Also, when a new non-priority flow is added, the controller 200 uses the collected information to set routes for all non-priority flows for the transmitting terminal 10 or the transfer device 40. In this way, when a new priority flow or a new non-priority flow is added, the controller 200 optimizes not only the new priority flow but also the non-priority flows, thereby increasing the number of flows, including non-priority flows, that can be accommodated in the network.

In addition, when a new priority flow or a new non-priority flow is added, the controller 200 according to the first embodiment can suppress the addition of resources by optimizing and accommodating not only the new priority flow but also the non-priority flow.

In the controller 200 according to the first embodiment, when the flow path of the non-priority packets is determined by the determination unit 222, if the non-priority packets do not satisfy the QoS, the resource request unit 224 requests an increase in the bandwidth of the link between the transfer devices 40, the link having a flow rate that exceeds the maximum flow rate of each transfer device 40. This allows the controller 200 according to the first embodiment to avoid congestion caused by a lack of resources.

In the controller 200 according to the first embodiment, the acquisition unit 221 further acquires bandwidth information of each link between each transfer device 40, and the determination unit 222 determines the path of the flow of non-priority packets based further on the bandwidth information acquired by the acquisition unit 221. This allows the controller 200 according to the first embodiment to determine a path of the non-priority flow that reduces the bandwidth of each link between each transfer device 40.

Second Embodiment
A second embodiment will be described below, in which a non-priority flow is optimized when a priority flow or a non-priority flow is deleted.

[1. Example of control system configuration]
First, the configuration of a control system 1X according to the second embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram showing an example of the configuration of a control system 1X according to the second embodiment. As shown in Fig. 9, the control system 1X according to the second embodiment has a controller 200X instead of the controller 200 in the control system 1 according to the first embodiment of Fig. 1.

[2. Controller configuration example]
Next, the configuration of the controller 200X will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of the configuration of the controller 200X according to the second embodiment. As shown in Fig. 10, the controller 200 has a control unit 220X instead of the control unit 220 compared to the controller 200 in Fig. 2. The control unit 220X has a determination unit 222X and a setting unit 223X instead of the determination unit 222 and the setting unit 223 compared to the control unit 220 in Fig. 2.

When a priority flow is deleted, the determination unit 222X further determines a route for a non-priority flow based on the topology information acquired by the acquisition unit 221 and the information on the forwarding delay of each transfer device 40. Similarly, when a non-priority flow is deleted, the determination unit 222X further determines a route for a non-priority flow based on the topology information acquired by the acquisition unit 221 and the information on the forwarding delay of each transfer device 40.

The following describes in detail the configuration in which the determination unit 222X determines the path of the non-priority flow when a priority flow or non-priority flow is deleted. For example, when the acquisition unit 221 has acquired bandwidth information of each link between each transfer device 40, the determination unit 222X may determine the path of the non-priority flow based on the bandwidth information acquired by the acquisition unit 221.

The determination unit 222X may use the objective function (ii) expressed by the above formula (2) to calculate the path of the non-priority flow by utilizing the optimal solution that is the result of the calculation by the linear programming problem solver, as in the first embodiment. In this case, the determination unit 222X determines the path of the non-priority flow by obtaining a real solution using the same pre-held parameters and variables as in the first embodiment.

Here, when a priority flow or a non-priority flow is deleted, the number of links used by these flows is reduced, and unlike when these flows are added, the link bandwidth usually does not exceed the maximum flow rate of each transfer device 40. Therefore, when a priority flow or a non-priority flow is deleted, unlike when these flows are added, there is no need to request the resource request unit 224 to add bandwidth to a link with a flow rate that exceeds the maximum flow rate of each transfer device 40 in the optimization variables. Instead, the determination unit 222X may determine the route for the flow of non-priority packets only when at least one of the bandwidths of each link indicated by the bandwidth information acquired by the acquisition unit 221 is reduced.

The setting unit 223X sets the path of the flow of non-priority packets determined by the determination unit 222X to the transfer device 40 or the transmitting terminal 10.

3. Flow deletion procedure
Next, a procedure for transferring a deleted flow by the control system 1X according to the second embodiment (a flow deletion procedure) will be described with reference to Figures 11 and 12. Figures 11 and 12 are diagrams showing an example of a flow deletion procedure according to the second embodiment.

First, the flow deletion procedure when a priority flow is deleted will be described with reference to FIG. 11. As shown in FIG. 11, the control system 1X of this embodiment includes a controller 200X instead of the controller 200, as compared to the control system 1 of FIG. 3 and FIG. 4.

First, the transmitting terminal 10 requests the controller 200X to delete the accommodated priority flow (21). In this case, the transmitting terminal 10 notifies the controller 200X of the source node and destination node of the deletion priority flow that is requested to be deleted. Next, the controller 200X determines the route of the non-priority flow based on the source node and destination node of the deletion priority flow notified by the transmitting terminal 10, topology information, and information on the forwarding delay of the forwarding device 40 (22). Here, if the bandwidth of at least one of the links is reduced, or if a resource that is being used is released, the controller 200X requests the orchestrator 30 to delete the released resource (23).

Next, the orchestrator 30, which has received the resource deletion request from the controller 200X, executes the resource deletion process (24). After that, the orchestrator 30 notifies the controller 200X that the resource deletion process has been successfully executed (25).

The controller 200X then sets the determined non-priority flow path for the transfer device 40, and cancels the setting of the deletion priority flow path (26). As a result, the non-priority flow path is set in the transfer device 40, and the deletion priority flow path setting is cancelled (27). Next, the transfer device 40 notifies the controller 200X that the non-priority flow path has been set successfully, and the deletion priority flow path setting has been cancelled (28). Next, the controller 200X notifies the sending terminal 10 that the non-priority flow path has been set successfully, and the deletion priority flow path setting has been cancelled (29).

Next, the flow deletion procedure when a non-priority flow is deleted will be described with reference to FIG. 12. As shown in FIG. 12, the control system 1X of this embodiment includes a controller 200X instead of the controller 200 in the control system 1 of FIG. 3 and FIG. 4.

First, the transmitting terminal 10 requests the controller 200X to delete the non-priority flow that is already accommodated (31). In this case, the transmitting terminal 10 notifies the controller 200X of the source node and destination node of the non-priority flow to be deleted. Next, the controller 200X determines the route of the non-priority flow based on the source node and destination node of the non-priority flow to be deleted notified by the transmitting terminal 10, topology information, and information on the forwarding delay of the forwarding device 40 (32). Here, if the bandwidth of at least one of the links is reduced, or if a resource that is being used is released, the controller 200X requests the orchestrator 30 to delete the released resource (33).

Next, the orchestrator 30, which has received the resource deletion request from the controller 200X, performs the resource deletion process (34). After that, the orchestrator 30 notifies the controller 200X that the resource deletion process has been successfully performed (35).

The controller 200X then sets the determined non-priority flow path for the transfer device 40 and cancels the path setting for the deleted non-priority flow (36). As a result, the non-priority flow path is set in the transfer device 40 and the path setting for the deleted non-priority flow is cancelled (37). Next, the transfer device 40 notifies the controller 200X that the non-priority flow path has been set successfully and the path setting for the deleted non-priority flow has been cancelled (38). Next, the controller 200X notifies the transmitting terminal 10 that the non-priority flow path has been set successfully and the path setting for the deleted non-priority flow has been cancelled (39).

[4. Delete flow]
An example of flow control (flow deletion) by route setting in the control system 1X according to the second embodiment when a flow is deleted will be described with reference to Figures 13 and 14. Figures 13 and 14 are diagrams showing an example of flow deletion according to the second embodiment.

First, an example of flow deletion when a priority flow is deleted will be described with reference to FIG. 13. FIG. 13(1) shows a flow for which no route is set, and shows non-priority flows (i) and (ii), a priority flow to be deleted for which deletion has been requested, and the delay time for each link between each transfer device 40. In FIG. 13(1), the route for non-priority flow (i) and the route for non-priority flow (ii) are not the same, and some of the routes do not overlap. Therefore, in some of these routes, there are resources that are used by non-priority flow (i) and non-priority flow (ii).

On the other hand, FIG. 13(2) shows a flow controlled by path setting. Here, the controller 200X performs flow control, sets paths for the non-priority flows (i) and (ii), and modifies them by rearranging the paths for the non-priority flows (i) and (ii) so as to maximize resources. Specifically, the controller 200X releases from use the link that is one of the resources in the arrow portion of FIG. 13(2) among the links included in the path of the non-priority flow (ii), while avoiding congestion between the path of the non-priority flow (i) and the path of the non-priority flow (ii). In this way, the controller 200X minimizes the amount of resources being used.

In this case, as in the first embodiment, the controller 200X performs optimization calculation (ii) to calculate a route for a non-priority flow that minimizes non-priority packets that do not satisfy the QoS and minimizes the maximum bandwidth of each link between each transfer device 40. The controller 200X then sets the route for the non-priority flow obtained by optimization calculation (ii) to the transfer device 40, thereby minimizing the amount of resources being used while avoiding congestion.

Next, an example of flow deletion when a non-priority flow is deleted will be described with reference to FIG. 14. FIG. 14 (1) shows a flow for which no route is set, and FIG. 14 (1) shows the non-priority flow, the deleted non-priority flow that is requesting deletion, and the delay time for each link between each transfer device 40. In FIG. 14 (1), the route of the non-priority flow and the route of the deleted non-priority flow are not the same, and some routes do not overlap. Therefore, in some of these routes, there are resources that are used by the non-priority flow and the deleted non-priority flow, respectively.

On the other hand, FIG. 14 (2) shows a flow controlled by route setting. Here, the controller 200X implements flow control, sets routes for non-priority flows, and modifies them by rearranging the routes for non-priority flows so as to maximize resources. Specifically, the controller 200X avoids congestion between the routes for non-priority flows and the routes for priority flows, and releases from use the links included in the routes for non-priority flows, which are one of the resources in the arrowed portion of FIG. 14 (2). In this way, the controller 200X minimizes the amount of resources being used.

5. Flowchart
A flow of flow control (flow deletion) by path setting of the controller 200X according to the second embodiment in the case where a flow is deleted will be described with reference to Figures 15 and 16. Figures 15 and 16 are flowcharts showing an example of the flow of flow deletion according to the second embodiment.

First, the flow of flow deletion when a priority flow is deleted will be described using FIG. 15. First, the decision unit 222X performs an optimization calculation (ii) of the non-priority flow with objective function (ii) using the priority flow to be deleted and existing non-priority flows (all non-priority flows) as variables (step S201). Specifically, the decision unit 222X performs an optimization calculation (ii) of the non-priority flow with variables of all non-priority flows to minimize non-priority packets that do not satisfy QoS and to calculate a route for the non-priority flow that minimizes the maximum bandwidth of each link between each transfer device 40.

The determination unit 222X determines whether or not there is a link whose bandwidth usage has decreased as a result of the calculation (step S202). When the determination unit 222X determines that there is a link whose bandwidth usage has decreased (step S202 "Yes"), it determines a route for the non-priority flow with the optimal variables of the optimization calculation (ii). In addition, the setting unit 223X sets the route for the non-priority flow with the optimal variables of the optimization calculation (ii) determined by the determination unit 222X to the transfer device 40 or the transmitting terminal 10 and transfers the flow (step S203). When the determination unit 222X determines that there is no link whose bandwidth usage has decreased (step S202 "No"), it ends the process without determining the route for the non-priority flow with the optimal variables of the optimization calculation (ii) and rearranging it. In this way, the determination unit 222X may determine the route for the flow of non-priority packets only when at least one of the bandwidths of each link indicated by the bandwidth information acquired by the acquisition unit 221 is reduced.

6. Effects of the Second Embodiment
As described above, in the controller 200X according to the second embodiment, when a flow of priority packets is deleted, the determination unit 222X determines a route for the flow of non-priority packets based on the topology information acquired by the acquisition unit 221 and information on the forwarding delay of each forwarding device 40. In addition, the setting unit 223X sets the route for the flow of non-priority packets determined by the determination unit 222X to the forwarding device 40 or the transmitting terminal 10.

As a result, the controller 200X according to the second embodiment can determine a route for non-priority flows that require large resources, and relocate the non-priority flows to that route, thereby reducing the amount of resources being used and freeing up those resources. In addition, since users of a TSN (Time-Sensitive Networking) network rent a network dedicated to the user from the network operator, they can reduce operating costs by reducing the amount of resources being used.

In addition, in the controller 200X according to the second embodiment, when a flow of non-priority packets is deleted, the determination unit 222X determines a path for the flow of non-priority packets based on the topology information acquired by the acquisition unit 221 and information on the forwarding delay of each forwarding device 40. In addition, the setting unit 223X sets the path for the flow of non-priority packets determined by the determination unit 222X to the forwarding device 40 or the transmitting terminal 10.

As a result, the controller 200X according to the second embodiment can determine a route for a non-priority flow that requires large resources, and relocate the non-priority flow to that route, thereby reducing the amount of resources being used and freeing up those resources. In addition, since users of a TSN network rent a network dedicated to them from a network operator, they can reduce operating costs by reducing the amount of resources being used.

Furthermore, in the controller 200X according to the second embodiment, the determination unit 222X determines the path for the flow of non-priority packets only when at least one of the bandwidths of the links indicated by the bandwidth information acquired by the acquisition unit 221 is reduced. As a result, the controller 200X determines the path for the flow of non-priority packets when the bandwidth of a link, which is one of the resources, is reduced, and therefore it is possible to reliably reduce the amount of resources being used.

〔program〕
It is also possible to create a program in which the processes executed by the controller 200 and the controller 200X described in the above embodiment are written in a language executable by a computer. In this case, the same effects as those of the above embodiment can be obtained by the computer executing the program. Furthermore, such a program may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read and executed by a computer to realize the same processes as those of the above embodiment.

FIG. 17 is a diagram showing an example of a computer that executes a program. As shown in FIG. 17, the computer 1000 has, for example, a memory 1010, a CPU 1020, a hard disk drive interface 1030, a disk drive interface 1040, a serial port interface 1050, a video adapter 1060, and a network interface 1070. Each of these components is connected by a bus 1080.

The memory 1010 includes a ROM (Read Only Memory) 1011 and a RAM 1012. The ROM 1011 stores a boot program such as a BIOS (Basic Input Output System). The hard disk drive interface 1030 is connected to a hard disk drive 1090. The disk drive interface 1040 is connected to a disk drive 1041. A removable storage medium such as a magnetic disk or optical disk is inserted into the disk drive 1041. The serial port interface 1050 is connected to, for example, a mouse 1110 and a keyboard 1120. The video adapter 1060 is connected to, for example, a display 1130.

As shown in FIG. 17, the hard disk drive 1090 stores, for example, an OS 1091, an application program 1092, a program module 1093, and program data 1094. Each table described in the above embodiment is stored, for example, in the hard disk drive 1090 or memory 1010.

The control program is stored in the hard disk drive 1090, for example, as a program module in which instructions to be executed by the computer 1000 are written. Specifically, a program module 1093 in which each process executed by the controller 2000 described in the above embodiment is written is stored in the hard disk drive 1090.

In addition, data used for information processing by the control program is stored as program data, for example, in the hard disk drive 1090. Then, the CPU 1020 reads the program module 1093 and program data 1094 stored in the hard disk drive 1090 into the RAM 1012 as necessary, and executes each of the above procedures.

The program module 1093 and program data 1094 related to the control program are not limited to being stored in the hard disk drive 1090, but may be stored in a removable storage medium, for example, and read by the CPU 1020 via the disk drive 1041 or the like. Alternatively, the program module 1093 and program data 1094 related to the control program may be stored in another computer connected via a network such as a LAN (Local Area Network) or a WAN (Wide Area Network), and read by the CPU 1020 via the network interface 1070.

1, 1X Control system 10

Transmission terminal

200, 200X Controller (control device)
210

Communication unit

220, 220X Control unit 221

Acquisition unit

222, 222X Determination unit 223, 223X Setting unit 224 Resource request unit 225 Topology update reception unit 230 Storage unit 231 NW topology storage unit 232 Accommodated flow storage unit 30 Orchestrator 40 Transfer device

Claims

an acquisition unit that acquires topology information indicating a connection form of a network and information on a transfer delay of each transfer device that transfers prioritized packets and non-priority packets;
a determination unit which, when a new flow of priority packets is added, determines at least one of a route and a transmission timing of the new flow of priority packets and a route of the flow of non-priority packets based on topology information and information on transfer delays of each transfer device acquired by the acquisition unit, and which, when a new flow of non-priority packets is added, determines a route of the new flow of non-priority packets and a route of the flow of non-priority packets based on the topology information and information on transfer delays of each transfer device acquired by the acquisition unit;
a setting unit that sets at least one of the flow path and transmission timing of the new priority packets and the flow path of the non-priority packets determined by the determination unit, or the flow path of the new non-priority packets and the flow path of the non-priority packets to the transfer device or a transmitting terminal.
when the flow of the priority packets is deleted, the determination unit determines a route for the flow of the non-priority packets based on the topology information acquired by the acquisition unit and information on a forwarding delay of each forwarding device;
2. The control device according to claim 1, wherein the setting unit sets the flow path of the non-priority packets determined by the determination unit to the transfer device or the transmitting terminal.
when the flow of the non-priority packets is deleted, the determination unit determines a route for the flow of the non-priority packets based on the topology information acquired by the acquisition unit and information on a forwarding delay of each forwarding device;
3. The control device according to claim 1, wherein the setting unit sets the flow path of the non-priority packets determined by the determination unit to the transfer device or the sending terminal.
The control device according to claim 1, further comprising a resource request unit that requests an increase in the bandwidth of a link between the transfer devices, the link having a flow rate that exceeds the maximum flow rate of the transfer device, if the non-priority packet does not satisfy QoS (Quality of Service) when the flow route of the non-priority packet is determined by the determination unit.
The acquisition unit further acquires information on a bandwidth of each link between each of the transfer devices,
2 . The control device according to claim 1 , wherein the determination unit determines a route for the flow of the non-priority packets further based on the bandwidth information acquired by the acquisition unit.
The control device according to claim 5, characterized in that the determination unit determines the path of the flow of the non-priority packets only when at least one of the bandwidths of the links indicated by the bandwidth information acquired by the acquisition unit decreases.
an acquisition step of acquiring topology information indicating a connection form of a network and information on a transfer delay of each transfer device that transfers prioritized packets and non-priority packets;
a determining step of, when a new flow of priority packets is added, determining at least one of a route and a transmission timing of the new flow of priority packets and a route of the flow of non-priority packets based on the topology information acquired in the acquiring step and information on the transfer delay of each transfer device, and, when a new flow of non-priority packets is added, determining a route of the new flow of non-priority packets and a route of the flow of non-priority packets based on the topology information acquired in the acquiring step and information on the transfer delay of each transfer device;
a setting step of setting at least one of the flow route and transmission timing of the new priority packets and the flow route of the non-priority packets, or the flow route of the new non-priority packets and the flow route of the non-priority packets, determined by the determination step, to the transfer device or a transmitting terminal.
an acquisition step of acquiring topology information indicating a connection form of a network and information on a transfer delay of each transfer device that transfers prioritized packets and non-priority packets;
a determining step of, when a new flow of priority packets is added, determining at least one of a route and a transmission timing of the new flow of priority packets and a route of the flow of non-priority packets based on the topology information acquired in the acquiring step and information on the transfer delay of each transfer device, and, when a new flow of non-priority packets is added, determining a route of the new flow of non-priority packets and a route of the flow of non-priority packets based on the topology information acquired in the acquiring step and information on the transfer delay of each transfer device;
and a setting step of setting at least one of the flow route and transmission timing of the new priority packets and the flow route of the non-priority packets determined by the determination step, or the flow route of the new non-priority packets and the flow route of the non-priority packets, in the transfer device or a transmitting terminal.