Frame transfer device, control method, and control program

Description

Technical Field

[0001] The present disclosure relates to power saving of a frame transfer device.

Background Art

[0002] In the field of communication devices, the communication speed and transfer speed have been improving year by year, and the power consumption has been increasing. On the other hand, power saving is being achieved by device process miniaturization or device power control. Power saving aiming at achieving carbon neutrality with zero greenhouse gas emissions by 2050 is required in each field.

[0003] Patent Document 1 describes that a plurality of packet processing circuits with different processing performances are implemented inside a communication device, and an optimal processing circuit is selected and used for the amount of data input within a certain time. The plurality of packet processing circuits with different processing performances are, for example, a high-speed circuit, a medium-speed circuit, and a low-speed circuit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Normally, a processing circuit implemented in a device consumes a certain amount of power or more even when it does not process data. Therefore, as described in Patent Document 1, simply selecting and using an optimal processing circuit for the amount of data is not sufficient to reduce the power consumption. An object of the present disclosure is to enable power saving of a frame transfer device.

Means for Solving the Problems

[0006] The frame transfer device according to the present disclosure is A power-saving switch, a switch between the power-saving switch and a high-performance switch with higher power consumption and higher performance than the power-saving switch, A control unit that activates one of the power-saving switch and the high-performance switch and deactivates the other according to the network load, A distribution unit that distributes frames received for the switch activated by the control unit and is provided with.

Effect of the Invention

[0007] In the present disclosure, one switch is activated and the other switch is deactivated according to the network load. By deactivating the other switch, power saving of the entire frame transfer device can be realized.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Embodiment 1. ***Description of Configuration*** With reference to FIG. 1, the configuration of frame transfer device 10 according to Embodiment 1 will be described. Frame transfer device 10 is a computer including interface unit 11, distribution unit 12, multiplexing unit 13, control unit 14, and switch 20 including power-saving switch 21 and high-performance switch 22. Interface unit 11, distribution unit 12, multiplexing unit 13, and control unit 14 are realized by an electronic circuit such as an LSI. LSI is an abbreviation for Large-Scale Integration. At least a part of interface unit 11, distribution unit 12, multiplexing unit 13, and control unit 14 may be realized by software. Power-saving switch 21 and high-performance switch 22 are each realized by an electronic circuit such as an LSI. Alternatively, power-saving switch 21 and high-performance switch 22 may each be a device operable alone.

[0010] Switch 20 has a function of transferring communication frames in accordance with predetermined rules or priorities in order. When performing order control, switch 20 requires a frame buffer. If the capacity of the frame buffer is large, it can withstand the processing of receiving many communication frames for a long time. That is, if the capacity of the frame buffer is large, it is of high performance. On the other hand, if the capacity of the frame buffer is large, the power consumption by the frame buffer increases, and the power consumption for controlling the frame buffer also increases. That is, if the capacity of the frame buffer is large, the power consumption also increases. Here, the high-performance switch 22 is a switch 20 that is more power-consuming and higher-performance than the power-saving switch 21.

[0011] The interface unit 11 is a network interface between the frame transfer device 10 and an external network 90. That is, the frame transfer device 10 is connected to the external network 90 by the interface unit 11. There are various standards and communication media for network interfaces, but the type is not limited here.

[0012] Referring to FIG. 2, the configuration of the interface unit 11, the distribution unit 12, and the multiplexing unit 13 according to Embodiment 1 will be described. The interface unit 11, the distribution unit 12, and the multiplexing unit 13 are provided corresponding to each of the plurality of networks 90. In FIG. 2, it is assumed that there are n networks 90 from network 90-1 to network 90n. The interface unit 11, the distribution unit 12, and the multiplexing unit 13 are respectively provided corresponding to the network 90. The frame received from the network 90 is processed by the corresponding interface unit 11, distribution unit 12, and multiplexing unit 13. For example, the frame received from network 90-1 is processed by interface unit 11-1, distribution unit 12-1, and multiplexing unit 13-1.

[0013] ***Description of the operation*** Referring to FIGS. 3 to 9, the operation of the frame transfer device 10 according to Embodiment 1 will be described. The operation procedure of the frame transfer device 10 according to Embodiment 1 corresponds to the control method of the frame transfer device 10 according to Embodiment 1. Further, the program for realizing the operation of the frame transfer device 10 according to Embodiment 1 corresponds to the control program of the frame transfer device 10 according to Embodiment 1.

[0014] The operation of the frame transfer device 10 according to Embodiment 1 includes a transfer process and a switch control process. The transfer process and the switch control process are executed in parallel.

[0015] Referring to FIG. 3, the transfer process of the frame transfer device 10 according to Embodiment 1 will be described. (Step S11: Reception process) The interface unit 11 receives a communication signal 31 such as an electrical signal or an optical signal for communication from the network 90. The interface unit 11 regenerates a communication frame 32 from the communication signal 31 and inputs the communication frame 32 to the distribution unit 12. The interface unit 11 has a function of regenerating the communication frame 32 from the communication signal 31 for each network 90.

[0016] (Step S12: Distribution process) The distribution unit 12 distributes and inputs the communication frame 32 to the power saving switch 21 or the high performance switch 22 according to the distribution instruction information 34 transmitted from the control unit 14 in the switch control process.

[0017] (Step S13: Switch process) The power saving switch 21 or the high performance switch 22 inputs the input communication frame 32 to the multiplexing unit 13 in the order according to a predetermined rule or priority. As a result, the communication frame 32 will be transferred in the order according to a predetermined rule or priority.

[0018] (Step S14: Multiplexing process) The multiplexing unit 13 performs multiplexing to avoid collisions of the communication frames 32 output to the interface unit 11 corresponding to the same network 90 by the power-saving switch 21 or the high-performance switch 22. Thereby, the multiplexing unit 13 combines the communication frames 32 into one in the order of input and then inputs them to the interface unit 11.

[0019] (Step S15: Transfer process) The interface unit 11 converts the communication frame 32 input by the multiplexing unit 13 into a communication signal 31 and then outputs it to the network 90.

[0020] Referring to FIG. 4, the switch control process according to Embodiment 1 will be described. (Step S21: Information transmission process) The distribution unit 12 periodically identifies the traffic volume per unit time of the communication frames 32 input from the interface unit 11. Then, the distribution unit 12 transmits traffic status information 33 indicating the identified traffic volume to the control unit 14. The power-saving switch 21 and the high-performance switch 22 each transmit internal traffic counter information, transfer count, discard count, and other statistical information, frame buffer usage status, MAC learning result information, etc. to the control unit 14 as switch internal information 35. MAC is the abbreviation of Media Access Control address. Note that the control unit 14 may acquire the switch internal information 35. As a method for transmitting the switch internal information 35, a method according to the function of the switch 20 is used. For example, as a method for transmitting the switch internal information 35, there are an interrupt process from the switch 20 and a polling process by the control unit 14.

[0021] (Step S22: Control process) The control unit 14 activates one of the switches 20, i.e., the power-saving switch 21 or the high-performance switch 22, and deactivates the other switch 20 according to the network load. At this time, the control unit 14 uses the traffic status information 33 and the switch internal information 35 to determine which of the power-saving switch 21 and the high-performance switch 22 to activate. Then, the control unit 14 activates one of the switches 20 and deactivates the other switch 20 by transmitting a control signal 36 to the power-saving switch 21 and the high-performance switch 22. In addition, the control unit 14 transmits the distribution instruction information 34 indicating the activated switch 20 as the input destination to the distribution unit 12. Note that, in order to maximize the power-saving effect, when the frame transfer device 10 is started up, the control unit 14 activates the power-saving switch 21 and deactivates the high-performance switch 22 as the initial state.

[0022] Here, the power-saving switch 21 and the high-performance switch 22 each transition between the activated state and the deactivated state under the control from the control unit 14. The communication frame 32 from the distribution unit 12 is input to the activated switch 20, and the control is such that the communication frame 32 is not input to the deactivated switch 20.

[0023] With reference to FIGS. 5 to 8, the control process (step S22 in FIG. 4) according to the first embodiment will be described. With reference to FIGS. 5 and 6, the process of switching the activated switch 20 from the power-saving switch 21 to the high-performance switch 22 will be described.

[0024] (Step S101: Load monitoring process) The control unit 14 monitors the network load. Here, the control unit 14 calculates the predicted load, which is the network load after the reference time, and compares the predicted load with the first threshold value. Specifically, the control unit 14 calculates the predicted usage rate of the frame buffer of the power-saving switch 21 as the predicted load. The control unit 14 calculates the increase and decrease curve of the usage rate of the frame buffer by using the traffic situation information 33 and the switch internal information 35 transmitted from the power-saving switch 21. The control unit 14 specifies the predicted usage rate after the reference time from the increase and decrease curve. Then, the control unit 14 compares the predicted usage rate with the first threshold value. For example, the control unit 14 predicts the usage rate of the frame buffer at each time point from the most recent frame buffer usage status indicated by the switch internal information 35 and the traffic volume expected to be input at each future time point. Thereby, the increase and decrease curve of the usage rate of the frame buffer is specified. Regarding the traffic volume expected to be input at each time point, the control unit 14 predicts from the past traffic situation information 33. The control unit 14 predicts the traffic volume expected to be input at each time point by learning the change in the traffic flow indicated by the past traffic situation information 33. As a result, as the operation period becomes longer and learning progresses, the prediction accuracy of the traffic volume becomes higher. As a result, the increase and decrease curve of the usage rate of the frame buffer is also accurately predicted.

[0025] (Step S102: First determination process) The control unit 14 determines whether the predicted usage rate is higher than the first threshold value. If the predicted usage rate is higher than the first threshold value, the control unit 14 advances the process to step S103. On the other hand, if the predicted usage rate is not higher than the first threshold value, the control unit 14 returns the process to step S101.

[0026] (Step S103: Standby process) The control unit 14 waits until the switching judgment period elapses from the first confirmation time when the determination in step S102 is made. The switching judgment period is set in advance.

[0027] (Step S104: Second determination process) The control unit 14 determines whether the predicted usage rate is higher than the first threshold value. When the predicted usage rate is higher than the first threshold, the control unit 14 proceeds with the process to step S105. On the other hand, when the predicted usage rate is not higher than the first threshold, the control unit 14 returns the process to step S101.

[0028] (Step S105: Activation process) The control unit 14 transmits a control signal 36 to activate the high-performance switch 22. There are cold boot and warm boot for activation. Cold boot is to start after supplying power to the high-performance switch 22. Warm boot is to release the stopped state of the high-performance switch 22. The stopped state is either the sleep state or the suspend state. The control unit 14 sets information necessary for the transfer of the communication frame 32 such as the MAC learning result updated by the power-saving switch 21 during the inactive state of the high-performance switch 22, to the high-performance switch 22. The MAC learning result is information included in the switch internal information 35. Thereby, the state of the high-performance switch 22 is synchronized with the state of the power-saving switch 21.

[0029] (Step S106: State monitoring process) The control unit 14 monitors the state of the high-performance switch 22. For example, information regarding the state of the high-performance switch 22 is acquired by an interrupt process from the high-performance switch 22 or a polling process by the control unit 14.

[0030] (Step S107: State determination process) The control unit 14 determines whether or not the transition of the high-performance switch 22 from the inactive state to the active state has been completed. When the transition is completed and the stable operation has been entered, the control unit 14 proceeds with the process to step S108. On the other hand, when the transition has not been completed and the stable operation has not been entered, the control unit 14 returns the process to step S106.

[0031] (Step S108: Allocation instruction process) The control unit 14 transmits the distribution instruction information 34 indicating the high-performance switch 22 as the destination to the distribution unit 12. That is, when the transition of the high-performance switch 22 to the active state is completed and it enters the stable operation, the control unit 14 instructs the distribution unit 12 to use the high-performance switch 22 as the destination. That is, the control unit 14 maintains the state with the power-saving switch 21 as the destination until the transition of the high-performance switch 22 to the active state is completed and it enters the stable operation.

[0032] (Step S109: Usage monitoring process) The control unit 14 monitors the frame buffer usage status included in the switch internal information 35 transmitted from the power-saving switch 21.

[0033] (Step S110: Usage determination process) The control unit 14 determines whether or not the frame buffer usage rate of the power-saving switch 21 has become zero. The fact that the frame buffer usage rate has become zero means that there is no output frame from the power-saving switch 21. When the frame buffer usage rate becomes zero, the control unit 14 advances the process to step S111. On the other hand, when the frame buffer usage rate has not become zero, the control unit 14 returns the process to step S109.

[0034] (Step S111: Deactivation process) The control unit 14 transmits the control signal 36 to deactivate the power-saving switch 21. When the activation is a cold boot in step S205 described later, the deactivation is to shut down the power-saving switch 21 and then cut off the power supply. When the activation is a warm boot in step S205 described later, the deactivation is to put the power-saving switch 21 in the stopped state.

[0035] In steps S101 to S104, the control unit 14 determines whether the predicted load is higher than the first threshold at the first confirmation time point and whether the predicted load is higher than the first threshold at the second confirmation time point after the switching judgment period at the first confirmation time point. At time T11 in FIG. 6, the predicted load is higher than the first threshold. However, at time T12, which is only after the switching determination period at time T11, the predicted load is lower than the first threshold. Therefore, in this case, the control unit 14 does not determine to activate the high-performance switch 22, and maintains the power-saving switch 21 in the activated state. At time T13 in FIG. 6, the predicted load is higher than the first threshold. Also, at time T14, which is only after the switching determination period at time T13, the predicted load is higher than the first threshold. Therefore, in this case, at time T14, the control unit 14 determines to activate the high-performance switch 22.

[0036] The first threshold is determined based on the configuration of the network to be applied, generally expected traffic fluctuation information such as congestion time bands, and statistical information on traffic fluctuations learned by the frame transfer device 10. The first threshold is set in advance or the optimal value is automatically reflected according to the learning result. The first threshold is set to a value based on the fact that the power-saving switch 21 is selected until the time when the activation process of the high-performance switch 22 transitions to stable operation.

[0037] With reference to FIGS. 7 and 8, the process of switching the switch 20 in the activated state from the high-performance switch 22 to the power-saving switch 21 will be described.

[0038] (Step S201: Load monitoring process) The control unit 14 monitors the network load. Here, the control unit 14 calculates the predicted load, which is the network load after the reference time, and compares the predicted load with the second threshold. Specifically, the control unit 14 calculates the predicted usage rate of the frame buffer of the high-performance switch 22 as the predicted load. The control unit 14 calculates the increase and decrease curve of the usage rate of the frame buffer using the traffic situation information 33 and the switch internal information 35 transmitted from the high-performance switch 22. The control unit 14 specifies the predicted usage rate after the reference time from the increase and decrease curve. Then, the control unit 14 compares the predicted usage rate with the second threshold.

[0039] (Step S202: First determination process) The control unit 14 determines whether the predicted usage rate is lower than the second threshold value. If the predicted usage rate is lower than the second threshold value, the control unit 14 advances the process to step S203. On the other hand, if the predicted usage rate is not lower than the second threshold value, the control unit 14 returns the process to step S201.

[0040] (Step S203: Standby process) The control unit 14 waits until the switching determination period elapses from the first confirmation time when the determination in step S202 is made.

[0041] (Step S204: Second determination process) The control unit 14 determines whether the predicted usage rate is lower than the second threshold value. If the predicted usage rate is lower than the second threshold value, the control unit 14 advances the process to step S205. On the other hand, if the predicted usage rate is not lower than the second threshold value, the control unit 14 returns the process to step S201.

[0042] (Step S205: Activation process) The control unit 14 transmits a control signal 36 to activate the power-saving switch 21. There are cold boot and warm boot for activation. Cold boot is to start after supplying power to the power-saving switch 21. Warm boot is to release the stopped state of the power-saving switch 21. The control unit 14 sets information necessary for transferring communication frames 32 such as MAC learning results updated by the high-performance switch 22 while the power-saving switch 21 is in an inactive state, to the high-performance switch 22. Thereby, the state of the power-saving switch 21 is synchronized with the state of the high-performance switch 22.

[0043] (Step S206: State monitoring process) The control unit 14 monitors the state of the power-saving switch 21. For example, information regarding the state of the power-saving switch 21 is acquired by an interrupt process from the power-saving switch 21 or a polling process by the control unit 14.

[0044] (Step S207: State Determination Process) The control unit 14 determines whether the transition of the power saving switch 21 from the inactive state to the active state has been completed. When the transition is completed and the stable operation has started, the control unit 14 proceeds with the process to step S208. On the other hand, when the transition has not been completed and the stable operation has not started, the control unit 14 returns the process to step S206.

[0045] (Step S208: Assignment Instruction Process) The control unit 14 transmits the assignment instruction information 34 indicating the power saving switch 21 as the input destination to the assignment unit 12. That is, when the transition of the power saving switch 21 to the active state is completed and the stable operation starts, the control unit 14 instructs the assignment unit 12 to use the power saving switch 21 as the input destination. That is, the control unit 14 maintains the state with the high-performance switch 22 as the input destination until the transition of the power saving switch 21 to the active state is completed and the stable operation starts.

[0046] (Step S209: Usage Monitoring Process) The control unit 14 monitors the frame buffer usage status included in the switch internal information 35 transmitted from the high-performance switch 22.

[0047] (Step S210: Usage Determination Process) The control unit 14 determines whether the frame buffer usage rate of the high-performance switch 22 has become zero. The fact that the frame buffer usage rate has become zero means that there is no output frame from the high-performance switch 22. When the frame buffer usage rate has become zero, the control unit 14 proceeds with the process to step S211. On the other hand, when the frame buffer usage rate has not become zero, the control unit 14 returns the process to step S209.

[0048] (Step S211: Deactivation Process) The control unit 14 transmits a control signal 36 to deactivate the high-performance switch 22. When activation is a cold boot in step S105 described above, deactivation is to cut off the power supply after shutting down the high-performance switch 22. When activation is a warm boot in step S105 described above, deactivation is to set the high-performance switch 22 to a stopped state.

[0049] From step S201 to step S204, the control unit 14 determines whether the predicted load is lower than the second threshold at the first confirmation time point and whether the predicted load is lower than the second threshold at the second confirmation time point, which is after the switching determination period of the first confirmation time point. At time T21 in FIG. 8, the predicted load is lower than the second threshold. However, at time T22, which is after the switching determination period of time T21, the predicted load is higher than the second threshold. Therefore, in this case, the control unit 14 does not determine to activate the power-saving switch 21 and maintains the high-performance switch 22 in an activated state. At time T23 in FIG. 8, the predicted load is lower than the second threshold. Also, at time T24, which is after the switching determination period of time T23, the predicted load is lower than the second threshold. Therefore, in this case, at time T24, the control unit 14 determines to activate the power-saving switch 21.

[0050] The second threshold is determined based on the configuration of the network to be applied, generally expected traffic fluctuation information such as congestion time zones, and statistical information on traffic fluctuations learned by the frame transfer device 10. The second threshold is set in advance or the optimal value is automatically reflected according to the learning result. The second threshold is set with a margin so that the switch 20 to be activated does not repeatedly switch at short intervals considering the frame buffer size of the power-saving switch 21.

[0051] Referring to FIG. 9, the state transition of the switch 20 according to Embodiment 1 will be described. The frame transfer device 10 is activated. Then, the power-saving switch 21 maintains its activated state (S301), and when it is determined that the performance of the power-saving switch 21 cannot handle the processing due to an increase in the communication load, the high-performance switch 22 is activated (S302). After waiting for the stable operation of the high-performance switch 22, the power-saving switch 21 is deactivated, and only the high-performance switch 22 remains in the activated state (S303). When the communication load decreases and it is determined that the processing can be performed with the performance of the power-saving switch 21, the power-saving switch 21 is activated (S304). After waiting for the stable operation of the power-saving switch 21, the high-performance switch 22 is deactivated, and only the power-saving switch 21 remains in the activated state (S301).

[0052] When multiplexing frames, transiently or constantly, the input amount on the input side, which is the frame multiplexing target, may exceed the output amount on the output side, which is the frame multiplexing result. In Embodiment 1, in the transient state where the switch 20 in the switch control process is switched, frame inputs are generated for the multiplexing unit 13 from both the high-performance switch 22 and the power-saving switch 20. During the period when the transient state continues, in the multiplexing unit 13, the input amount may exceed the output amount. Specifically, the transient state occurs during the following periods (1) and (2). The period of (1) is from when the high-performance switch 22 is selected as the input destination in step S108 of FIG. 5 until the frame buffer utilization rate of the power-saving switch 21 becomes zero in step S110. The period of (2) is from when the power-saving switch 21 is selected as the input destination in step S208 of FIG. 7 until the frame buffer utilization rate of the high-performance switch 22 becomes zero in step S210. In Embodiment 1, the multiplexing unit 13 has a frame buffer. And the multiplexing unit 13 temporarily stores the communication frames 32 output from the power-saving switch 21 and the high-performance switch 22 in the frame buffer, multiplexes them in order, and inputs them to the interface unit 11. Thereby, even when the input amount exceeds the output amount, it is possible to multiplex without missing the communication frames 32.

[0053] ***Effects of Embodiment 1*** As described above, the frame transfer device 10 according to Embodiment 1 activates one switch 20 and deactivates the other switch 20 according to the network load. Thereby, power saving of the entire frame transfer device 10 can be realized.

[0054] The frame transfer device 10 according to Embodiment 1 compares with the threshold value not only at the first confirmation time but also at the second confirmation time which is only after the switching determination period of the first confirmation time, and determines whether to switch the switch 20 to be in the activated state. Thereby, it is possible to prevent the switch 20 that is repeatedly activated in a short period from being switched. As a result, power consumption associated with the switching can be suppressed.

[0055] Embodiment 2. Embodiment 2 is different from Embodiment 1 in that there are three or more types of switches 20. In Embodiment 2, this difference will be described, and the description of the same points will be omitted.

[0056] In Embodiment 1, the frame transfer device 10 includes the switch 20 having two types of performances, i.e., the power-saving switch 21 and the high-performance switch 22. However, the frame transfer device 10 may include the switch 20 having three or more types of performances. For example, as shown in FIG. 10, the frame transfer device 10 may include, as the switch 20, a medium-performance switch 23 in addition to the power-saving switch 21 and the high-performance switch 22. The medium-performance switch 23 is a switch 20 that has a higher power consumption and higher performance than the power-saving switch 21 and lower power consumption and lower performance than the high-performance switch 22.

[0057] Referring to FIG. 11, the state transition of the switch 20 according to Embodiment 2 will be described. The frame transfer device 10 is activated. Then, the power-saving switch 21 maintains the activated state (S401). When it is determined that the processing cannot be performed with the performance of the power-saving switch 21 due to an increase in the communication load, first, the medium-performance switch 23 is activated (S402). After waiting for the stable operation of the medium-performance switch 23, the power-saving switch 21 is deactivated, and only the medium-performance switch 23 maintains the activated state (S403). When it is determined that the communication load further increases and the processing cannot be performed with the performance of the medium-performance switch 23, the high-performance switch 22 is activated (S404). After waiting for the stable operation of the high-performance switch 22, the medium-performance switch 23 is deactivated, and only the high-performance switch 22 maintains the activated state (S405). When the communication load decreases from the state of S403 and it is determined that the processing is possible with the performance of the power-saving switch 21, the power-saving switch 21 is activated (S408). After waiting for the stable operation of the power-saving switch 21, the medium-performance switch 23 is deactivated, and only the power-saving switch 21 maintains the activated state (S401) When the communication load decreases from the state of S405 and it is determined that the processing is possible with the performance of the medium-performance switch 23, the medium-performance switch 23 is activated (S406). After waiting for the stable operation of the medium-performance switch 23, the high-performance switch 22 is deactivated, and only the medium-performance switch 23 maintains the activated state (S407). Similar to the state of S403, when the communication load increases in the state of S407, the process transitions to S404, and when the communication load decreases, the process transitions to S401.

[0058] ***Effects of Embodiment 2*** As described above, the frame transfer device 10 according to Embodiment 2 includes three or more switches 2 0. Even in this case, while one switch 20 is activated according to the network load, the other switches 20 are deactivated. Thereby, power saving of the entire frame transfer device 10 can be realized.

[0059] Embodiment 3. Embodiment 3 differs from Embodiments 1 and 2 in that the multiplexing unit 13 does not have a frame buffer for frame multiplexing. In Embodiment 3, this difference will be described, and the description of the same points will be omitted. In Embodiment 3, the case of making a change to Embodiment 1 will be described. However, it is also possible to make a change to Embodiment 2.

[0060] In Embodiment 3, while omitting the frame buffer of the multiplexing unit 13, the switch 20 is switched in a procedure for preventing frame loss during frame multiplexing in the switch control process.

[0061] With reference to FIG. 12, the process of switching the switch 20 in the active state to the high-performance switch 22 from the power-saving switch 21 according to Embodiment 3 will be described. The processes from step S501 to S507 are the same as the processes from step S101 to S107 in FIG. 5.

[0062] (Step S508: Output prohibition setting process) After the high-performance switch 22 becomes stable, that is, after startup is completed and it is in a state of accepting various settings, the control unit 14 performs an operation to temporarily stop the output function of the high-performance switch 22. Here, the control unit 14 closes the output port of the high-performance switch 22. As a result, when the high-performance switch 22 receives the communication frame 32 from the distribution unit 12, it accumulates in the frame buffer of the high-performance switch 22 without transmitting it to the multiplexing unit 13.

[0063] The processes from step S509 to step S511 are the same as the processes from step S108 to S110 in FIG. 5.

[0064] (Step S512: Output permission setting process) After the buffer utilization rate of the power-saving switch 21 becomes zero, that is, after the state transitions to a state where there is no output frame from the power-saving switch 21, the control unit 14 releases the output prohibition setting that was temporarily set for the high-performance switch 22. Here, the control unit 14 releases the output port of the high-performance switch 22. As a result, the high-performance switch 22 starts to output the frames accumulated in the frame buffer to the multiplexing unit 13.

[0065] The process of step S513 is the same as the process of step S111 in FIG. 5.

[0066] Referring to FIG. 13, the process of switching the switch 20 in the activated state from the high-performance switch 22 to the power-saving switch 21 according to Embodiment 3 will be described. The processes from step S601 to S607 are the same as the processes from step S201 to S207 in FIG. 7.

[0067] (Step S608: Output Prohibition Setting Process) After the power-saving switch 21 becomes stable, that is, after startup is completed and it is in a state where it can accept various settings, the control unit 14 performs an operation to temporarily stop the output function of the power-saving switch 21. Here, the control unit 14 closes the output port of the power-saving switch 21. As a result, when the power-saving switch 21 receives the communication frame 32 from the distribution unit 12, it accumulates it in the frame buffer of the power-saving switch 21 without transmitting it to the multiplexing unit 13.

[0068] The processes from step S609 to step S611 are the same as the processes from step S208 to S210 in FIG. 7.

[0069] (Step S612: Output Permission Setting Process) After the buffer utilization rate of the high-performance switch 22 becomes zero, that is, after the state transitions to a state where there is no output frame from the high-performance switch 22, the control unit 14 releases the output prohibition setting that was temporarily set for the power-saving switch 21. Here, the control unit 14 releases the output port of the power-saving switch 21. As a result, the power-saving switch 21 starts to output the frames accumulated in the frame buffer to the multiplexing unit 13.

[0070] The process of step S613 is the same as the process of step S211 in FIG. 7.

[0071] ***Effects of Embodiment 3*** As described above, in the frame transfer device 10 according to Embodiment 3, communication frames 32 from the power-saving switch 21 and the high-performance switch 22 do not enter the multiplexing unit 13 at the same time. Therefore, the maximum input speed does not exceed the output speed, and a frame buffer for multiplexing the communication frames 32 becomes unnecessary. As a result, it is possible to realize a reduction in functions, miniaturization, and power saving of the multiplexing unit 13 and thus the frame transfer device 10.

[0072] Note that the "unit" in the above description may be read as "circuit", "step", "procedure", "process", or "processing circuit".

[0073] The embodiments and modification examples of the present disclosure have been described above. Some of these embodiments and modification examples may be implemented in combination. Also, any one or some of them may be partially implemented. Note that the present disclosure is not limited to the above embodiments and modification examples, and various changes can be made as necessary.

Description of Reference Numerals

[0074] 10 Frame transfer device, 11 Interface section, 12 Distribution section, 13 Multiplexing section, 14 Control section, 20 Switch, 21 Power-saving switch, 22 High-performance switch, 23 Medium-performance switch, 31 Communication signal, 32 Communication frame, 33 Traffic status information, 34 Distribution instruction information, 35 Internal switch information, 36 Control signal, 90 Network.

Claims

1. a power-saving switch; and a high-performance switch that consumes more power and has higher performance than the power-saving switch; a control unit that activates one of the power-saving switch and the high-performance switch and deactivates the other switch according to a network load; a distribution unit that distributes frames received to the switches activated by the control unit; Equipped with The control unit calculates a predicted load, which is the network load after a reference time, and determines whether to activate the power-saving switch or the high-performance switch by comparing the predicted load with a threshold value.When the power-saving switch is activated, if the predicted load becomes higher than a first threshold value, the control unit activates the high-performance switch and deactivates the power-saving switch.

2. a power-saving switch; and a high-performance switch that consumes more power and has higher performance than the power-saving switch; a control unit that activates one of the power-saving switch and the high-performance switch and deactivates the other switch according to a network load; a distribution unit that distributes frames received to the switches activated by the control unit; Equipped with The control unit calculates a predicted load, which is the network load after a reference time, and determines whether to activate the power-saving switch or the high-performance switch by comparing the predicted load with a threshold value.When the high-performance switch is activated, and the predicted load becomes lower than a second threshold value, the control unit activates the power-saving switch and deactivates the high-performance switch.

3. a power-saving switch; and a high-performance switch that consumes more power and has higher performance than the power-saving switch; a control unit that activates one of the power-saving switch and the high-performance switch and deactivates the other switch according to a network load; a distribution unit that distributes received frames to switches activated by the control unit; a multiplexing unit that multiplexes frames output from the switch; Equipped with A frame forwarding device in which the control unit activates one of the switches and then allows the output of frames from the one switch to the multiplexing unit only when there are no more frames to be output from the other switch to the multiplexing unit.

4. The control unit calculates a predicted load, which is a network load after a reference time, and compares the predicted load with a threshold value to determine whether to activate the power-saving switch or the high-performance switch.

4. The frame forwarding device according to claim 3.

5. The frame forwarding device described in claim 1, wherein the control unit activates the high-performance switch and deactivates the power-saving switch when the predicted load is higher than the first threshold at a first confirmation time point and when the predicted load is higher than the first threshold at a second confirmation time point a switching determination period after the first confirmation time point.

6. The control unit activates the power-saving switch and deactivates the high-performance switch when the predicted load at the first confirmation time is lower than the second threshold and when the predicted load at the second confirmation time, which is a switching determination period after the first confirmation time, is lower than the second threshold.

7. The control unit deactivates the other switch after activating the one switch.

4. The frame forwarding device according to claim 1.

8. Deactivating the switch means shutting down the switch and cutting off the power supply. Activating a switch means powering it on.

4. The frame forwarding device according to claim 1.

9. Deactivating the switch means putting the switch into a halt state, which is either a sleep state or a suspend state; Activating the switch means releasing the stopped state of the switch.

4. The frame forwarding device according to claim 1.

10. The frame forwarding device further a multiplexing unit for multiplexing frames output from the switch, the multiplexing unit having a frame buffer for temporarily storing the frames output from the switch; The frame forwarding device according to any one of claims 1 to 3, comprising:

11. A control method for a frame forwarding device including a power-saving switch and a high-performance switch that consumes more power and has higher performance than the power-saving switch, a computer activating one of the power-saving switch and the high-performance switch and deactivating the other switch according to a network load; The computer routes the received frames to the activated switches, A control method in which a computer calculates a predicted load, which is the network load after a reference time, and determines whether to activate the power-saving switch or the high-performance switch by comparing the predicted load with a threshold value, and when the power-saving switch is activated and the predicted load becomes higher than a first threshold value, activates the high-performance switch and deactivates the power-saving switch.

12. A control method for a frame forwarding device including a power-saving switch and a high-performance switch that consumes more power and has higher performance than the power-saving switch, a computer activating one of the power-saving switch and the high-performance switch and deactivating the other switch according to a network load; The computer routes the received frames to the activated switches, A control method in which a computer calculates a predicted load, which is the network load after a reference time, and determines whether to activate the power-saving switch or the high-performance switch by comparing the predicted load with a threshold value, and when the high-performance switch is activated, if the predicted load becomes lower than a second threshold value, the computer activates the power-saving switch and deactivates the high-performance switch.

13. A control method for a frame forwarding device including a power-saving switch and a high-performance switch that consumes more power and has higher performance than the power-saving switch, a computer activating one of the power-saving switch and the high-performance switch and deactivating the other switch according to a network load; The computer routes the received frames to the activated switches, a computer multiplexing the frames output from the switch; A control method in which a computer activates one of the switches, and then permits output of frames from the one of the switches when there are no more frames output from the other of the switches.

14. A control program for controlling a frame forwarding device including a power-saving switch and a high-performance switch that consumes more power and has higher performance than the power-saving switch, a control process for activating one of the power-saving switch and the high-performance switch and deactivating the other switch according to a network load; a distribution process for distributing received frames to the switches activated by the control process; on the computer, In the control process, a predicted load, which is the network load after a reference time, is calculated, and the predicted load is compared with a threshold value to determine whether to activate the power-saving switch or the high-performance switch.When the power-saving switch is activated and the predicted load becomes higher than a first threshold value, the control program activates the high-performance switch and deactivates the power-saving switch.

15. A control program for controlling a frame forwarding device including a power-saving switch and a high-performance switch that consumes more power and has higher performance than the power-saving switch, a control process for activating one of the power-saving switch and the high-performance switch and deactivating the other switch according to a network load; a distribution process for distributing received frames to the switches activated by the control process; on the computer, In the control process, a predicted load, which is the network load after a reference time, is calculated, and the predicted load is compared with a threshold value to determine whether to activate the power-saving switch or the high-performance switch.When the high-performance switch is activated, if the predicted load becomes lower than a second threshold value, the control program activates the power-saving switch and deactivates the high-performance switch.

16. A control program for controlling a frame forwarding device including a power-saving switch and a high-performance switch that consumes more power and has higher performance than the power-saving switch, a control process for activating one of the power-saving switch and the high-performance switch and deactivating the other switch according to a network load; a distribution process for distributing received frames to the switches activated by the control process; a multiplexing process for multiplexing frames output from the switch; on the computer, In the control process, after activating the one switch, the control program permits output of frames from the one switch only when there is no output frame from the other switch.

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