Communication device and communication method

Abstract

A communication device connected to a higher-level device and a plurality of lower-level devices, said communication device comprising: a plurality of higher-level packages that communicate with the higher-level device; a plurality of lower-level packages that communicate with the lower-level devices; and a control unit that, on the basis of a downlink communication situation received by each of the higher-level packages from the higher-level device and a downlink communication situation received by each of the lower-level packages, determines whether each of the higher-level packages is brought into an operating state or a dormant state, and performs control.

Description

Communication device and communication method

[0001] The present invention relates to a communication device and a communication method.

[0002] A communication device has been proposed that achieves power saving by dynamically changing the number of startup packages according to the usage status of user communication (increase or decrease in traffic) (see, for example, Patent Document 1 and Patent Document 2). Such a communication device periodically acquires the amount of traffic flowing into the device itself (communication device) from a higher-level device and the frame discard rate for each user. When the acquired value exceeds a threshold value (when it enters an excess state), it activates packages in a stopped state. By activating the packages, the processing ability for communication is improved, enabling it to handle an increase in the amount of traffic, and an improvement in the frame discard rate is realized. Then, when it no longer enters an excess state (when it returns to a normal state), the communication device stops some of the startup packages.

[0003] In such a communication device, quality control called QoS may be performed. In a communication device that executes this quality control, in a state where a temporary increase in traffic occurs for some specific users (so-called heavy users) (hereinafter referred to as "specific abnormal state"), from the perspective of fairness among users, there is little need to rescue by activating packages. Therefore, even if an excess state occurs under such a specific abnormal state, power consumption can be reduced by suppressing the activation of packages.

[0004] Japanese Patent Application Laid-Open No. 2017-208757, Japanese Patent Application Laid-Open No. 2018-133680

[0005] However, it was difficult to suppress the activation of unnecessary packages for downlink frames. This is because the data is shaped to fit the line bandwidth on the upstream device before being forwarded. In other words, even if the communication device monitors only the inflow traffic to packages destined for upstream devices, it is not possible to accurately determine whether the problem is caused by a few specific users dominating the line (i.e., whether a specific abnormal condition is the cause). While obtaining frame counters for all users might allow for more accurate determination, this method would increase the processing load and negate the power saving benefits. Therefore, it is necessary to determine whether a specific abnormal condition is occurring with higher accuracy while keeping the processing load down.

[0006] This invention has been made in view of the circumstances described above, and provides a technology that enables more accurate determination of whether or not a communication overload condition is caused by increased communication from a specific group of users.

[0007] One aspect of the present invention is a communication device connected to a higher-level device and a plurality of lower-level devices, comprising: a plurality of higher-level packages that communicate with the higher-level device; a plurality of lower-level packages that communicate with the lower-level devices; and a control unit that determines and controls whether to put each higher-level package into an operational state or a dormant state based on the downstream communication status received by the higher-level packages from the higher-level device and the downstream communication status received by each lower-level package.

[0008] One aspect of the present invention is a communication method performed by a communication device that is connected to a higher-level device and a plurality of lower-level devices, comprising a plurality of higher-level packages that communicate with the higher-level device and a plurality of lower-level packages that communicate with the lower-level devices, the communication method comprising a control step of determining and controlling whether to put each higher-level package into an operational state or a dormant state based on the downstream communication status received by the higher-level package from the higher-level device and the downstream communication status received by each lower-level package.

[0009] This invention makes it possible to determine with greater accuracy whether a communication overload is caused by increased communication from a specific group of users.

[0010] This is a schematic block diagram showing the system configuration of the communication system 100 of the present invention. This is a diagram showing the details of the control unit 24. This is a flowchart showing a first operation example of the communication device 20. This is a flowchart showing a first operation example of the communication device 20. This is a flowchart showing a second operation example of the communication device 20. This is a flowchart showing a third operation example of the communication device 20. This is a schematic diagram showing an example of the hardware configuration of the information processing device 90 applied to this embodiment.

[0011] [Principle] First, the principle of the present invention will be explained. Generally, communication between a communication device and a home device is achieved by performing predetermined processing on frames transferred from a higher-level device. Specific examples of predetermined processing include assigning a home device identifier, encrypting for security, and error correction. Due to the overhead incurred in performing such predetermined processing, the transfer speed decreases slightly when transferring frames from the communication device to the home device. In the following explanation, this slight decrease in transfer speed will be referred to as "specific speed reduction."

[0012] In a typical network configuration, traffic averaged across users is distributed and forwarded across multiple packages. Therefore, frame drops due to differences in transfer speed caused by specific speed reductions are rare. On the other hand, in situations where a certain group of users (hereinafter referred to as "heavy users") dominate the network (specific abnormal condition), traffic concentrates on the package containing the heavy users' in-home equipment. Therefore, frame drops may occur due to differences in transfer speed caused by specific speed reductions. Thus, by monitoring the traffic volume and frame drops for each user-containing package at the point where the specific speed reduction occurs, it is possible to determine with high accuracy whether or not a specific abnormal condition is occurring.

[0013] For example, if the transfer speed of a frame that has reached the upstream device is A, and A exceeds the line bandwidth between the upstream device and the communication device, the upstream device will shape the frame to fit the line bandwidth. If the transfer speed after this shaping is B, then A > B holds true. Furthermore, overhead is incurred due to the execution of predetermined processing by the communication device for frame transfer. With the occurrence of overhead, a specific speed reduction occurs in the transfer speed. As a result, the transfer speed B becomes even slower, resulting in a transfer speed C. That is, the relationship B > C holds true. In a specific abnormal state, at the point where such a specific speed reduction occurs (the communication package where the specific speed reduction occurred), events such as the traffic volume exceeding a threshold or frame dropping occur.

[0014] Therefore, in this invention, the amount of traffic and whether or not a package has been discarded for each user-acquired package is monitored to determine whether or not a specific abnormal state exists. Furthermore, by using package startup control based on monitoring the amount of traffic flowing from the higher-level device to the communication device (the amount of downlink frame traffic), the processing load required for the determination process is reduced, while determining whether or not a specific abnormal state exists, and if such a situation exists, a decision is made not to start the package (suppression of unnecessary package startup).

[0015] [System Configuration] Figure 1 is a schematic block diagram showing the system configuration of the communication system 100 of the present invention. The communication system 100 may be configured using a network such as a PON (Passive Optical Network). The communication system 100 comprises a higher-level device 10, a communication device 20, and a plurality of lower-level devices 30. The higher-level device 10 is a device located on the upper side of the network (for example, the core network side). The higher-level device 10 may be a relay device that relays communications, for example. The communication device 20 relays communications between the plurality of lower-level devices 30 and the higher-level device 10. The lower-level devices 30 are devices located on the lower side of the network relative to the communication device 20. The lower-level devices 30 are, for example, in-home devices. For example, the lower-level devices 30 are network termination devices and may be configured using an ONU (Optical Network Unit).

[0016] The communication device 20 comprises a plurality of upper-level packages 21, a plurality of lower-level packages, a storage unit 23, and a control unit 24. The upper-level packages 21 communicate between the communication device 20 on which they are installed and the upper-level device 10. Each upper-level package 21 transitions between an operational state and a dormant state according to the control unit 24. The operational state is a state in which normal operation (e.g., communication with the upper-level device 10) is performed, and the dormant state is a state in which some or all of the normal operation is not performed. The dormant state may be, for example, a power-off state. The power consumption per unit time when an upper-level package 21 is in the dormant state is lower than the power consumption per unit time when an upper-level package 21 is in the operational state. Therefore, in the communication device 20, only the upper-level packages 21 that need to be operated according to the communication status are in the operational state, and the remaining upper-level packages 21 are controlled to be in the dormant state. As a result, it is possible to reduce the power consumption in the communication device 20 without excessively reducing the efficiency of communication between the upper-level device 10 and the lower-level device 30.

[0017] The lower-level package 22 communicates between the communication device 20 on which it is installed and the lower-level device 30.

[0018] Each upper-level package 21 and each lower-level package 22 are in a state where they can communicate. The lower-level package 22 forwards the signal received from the lower-level device 30 to the upper-level package 21 that is in operation. In Figure 1, there is one upper-level device 10, but if the communication device 20 is connected to multiple upper-level devices 10, the lower-level package 22 forwards the signal received from the lower-level device 30 to the upper-level package 21 connected to the upper-level device 10 that is in operation. The upper-level package 21 that is in operation forwards the signal received from the upper-level device 10 to the lower-level package 22 connected to the lower-level device 30 that is the destination of that signal. If multiple upper-level packages 21 are in operation, the decision of which upper-level package 21 to which the signal is forwarded may be made according to rules maintained by the upper-level device 10. How the signal is forwarded from the upper-level device 10 to multiple upper-level packages 21 may be appropriately determined according to the specifications of the upper-level device 10, etc.

[0019] The storage unit 23 is configured using a storage device such as a magnetic hard disk drive or a semiconductor storage device. The storage unit 23 stores data used by the control unit 24.

[0020] Figure 2 shows the details of the control unit 24. The control unit 24 is composed of a processor such as a CPU (Central Processing Unit) and memory (main memory). The control unit 24 functions as a first traffic monitoring unit 241, a second traffic monitoring unit 242, a determination unit 243, and a package control unit 244 when the processor executes a program. Note that all or part of each function of the control unit 24 may be implemented using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The above program may be recorded on a computer-readable recording medium. Computer-readable recording media include, for example, portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, semiconductor memory devices (e.g., SSDs: Solid State Drives), and storage devices such as hard disks and semiconductor memory devices built into computer systems. The above program may be transmitted via a telecommunications line.

[0021] The control unit 24 may, for example, execute an application installed on its own device (communication device 20). The control unit 24 operates according to the program of the application being executed.

[0022] The first traffic monitoring unit 241 acquires the amount of traffic (hereinafter referred to as "upper-level traffic") received by the upper-level package 21 from the upper-level device 10. A predetermined threshold is set for the upper-level traffic. The threshold may vary depending on the applicable service level. The service level may be set collectively for all lower-level devices 30 housed in the communication device 20, for example. The threshold for the upper-level traffic may be set according to the service level for the type of data included in the traffic (e.g., text, still images, audio, video, etc.). The first traffic monitoring unit 241 monitors whether the upper-level traffic exceeds the threshold. The first traffic monitoring unit 241 records the monitoring results in the storage unit 23.

[0023] The second traffic monitoring unit 242 monitors traffic for each lower package 22. The second traffic monitoring unit 242 may, for example, acquire the amount of traffic received from the upper package 21 for each lower package 22 (hereinafter referred to as "lower traffic amount") and monitor whether it exceeds a predetermined threshold set in advance. Such a threshold may vary, for example, depending on the applicable service level. The second traffic monitoring unit 242 may, for example, monitor whether there are any dropped frames for each frame received from the upper package 21 for each lower package 22. The second traffic monitoring unit 242 may, for example, monitor whether there are any interrupted transmission frames to the upper package 21 for each lower package 22. The second traffic monitoring unit 242 records the monitoring results in the storage unit 23.

[0024] The determination unit 243 determines the state transition of the upper-level package 21 based on the monitoring results of the first traffic monitoring unit 241 and the monitoring results of the second traffic monitoring unit 242. For example, if the monitoring results of the first traffic monitoring unit 241 show that the amount of upper-level traffic exceeds a threshold, and the monitoring results of the second traffic monitoring unit 242 show that the behavior of lower-level traffic indicates the occurrence of a specific abnormal state, the determination unit 243 determines that it will operate with fewer upper-level packages 21 than the number of upper-level packages 21. In other words, if a specific abnormal state is present, the determination unit 243 determines that it will operate with fewer upper-level packages 21 than the number of upper-level packages 21. Specific examples of conditions indicating the occurrence of a specific abnormal state include the amount of lower-level traffic in a specific lower-level package 22 exceeding a threshold, frame discarding occurring in a specific lower-level package 22, or transmission interruption frames occurring in a specific lower-level package 22.

[0025] In this embodiment, the communication device 20 has two higher-level packages 21, but when a specific abnormal condition occurs, the number of higher-level packages 21 to be operated is "1". However, if the communication device 20 has three higher-level packages 21, the number of higher-level packages 21 to be operated when a specific abnormal condition occurs may be set to "1" or "2".

[0026] The package control unit 244 controls the state of the higher-level packages 21 according to the determination result of the determination unit 243. For example, if the number of higher-level packages 21 currently in operation is less than the number of higher-level packages that should be in operation as indicated by the determination result of the determination unit 243, the package control unit 244 transitions the dormant higher-level packages 21 to the operation state so that the numbers become equal. For example, if the number of higher-level packages 21 currently in operation is greater than the number of higher-level packages that should be in operation as indicated by the determination result of the determination unit 243, the package control unit 244 transitions the operation-state higher-level packages 21 to the dormant state so that the numbers become equal. The transition from operation to dormant state may be performed, for example, by powering off. The transition from dormant state to operation may be performed, for example, by powering on.

[0027] The first traffic monitoring unit 241 operates at predetermined intervals and may notify the second traffic monitoring unit 242 that processing is complete when recording is complete. The second traffic monitoring unit 242 operates in response to the notification from the first traffic monitoring unit 241 and may notify the determination unit 243 that processing is complete when recording is complete. The determination unit 243 operates in response to the notification from the second traffic monitoring unit 242 and may notify the package control unit 244 of the determination result when the determination process is complete. The package control unit 244 operates in response to the determination result from the determination unit 243 and may send an instruction to start or power off the target higher-level package 21.

[0028] Figures 3 and 4 are flowcharts showing a first example of operation of the communication device 20. First, the processing flow shown in Figure 3 will be explained. In Figure 3, it is assumed that processing starts from a state where one upper-level package 21 is operational and the other upper-level package 21 is in a dormant state. The first traffic monitoring unit 241 monitors the amount of traffic flowing from the upper-level device 10 to the communication device 20 (step S101). If the amount of traffic exceeds a preset threshold "L1", "Y1" is recorded in the first activation column of the storage unit 23. If the amount of traffic does not exceed the preset threshold "L1", "N1" is recorded in the first activation column of the storage unit 23. If the amount of traffic does not exceed the threshold "L1" (step S102-NO), the second traffic monitoring unit 242 does not need to operate.

[0029] At a minimum, if the traffic volume exceeds a preset threshold "L1" (step S102-YES), the second traffic monitoring unit 242 monitors the traffic for each lower package 22 (step S103). If the traffic volume exceeds a preset threshold "L2", "Y2" is recorded in the second activation column of the storage unit 23. In this case, the second activation column may be defined for each lower package 22. The second traffic monitoring unit 242 records a value in the second activation column corresponding to the lower package 22 being monitored. If the traffic volume does not exceed the preset threshold "L2", "N2" is recorded in the second activation column of the storage unit 23.

[0030] The determination unit 243 performs a determination process by referring to the values ​​recorded in the first activation column and the second activation column. If the value of the first activation column is "Y1" and the value of the second activation column of all lower packages 22 is "N2" (step S104-NO), the determination unit 243 outputs an activation instruction to the package control unit 244 for the dormant upper package 21 (step S105). The package control unit 244 transitions the dormant upper package 21 to an operational state in response to the activation instruction (step S106).

[0031] If the value of the first activation column is "N1" (step S102-NO), or if the value of the second activation column of at least one lower package 22 is "Y2" even if the value of the first activation column is "Y1" (step S104-YES), the determination unit 243 does not output an activation command, and instead, at the next timing (for example, after a certain period of time has elapsed), it refers to each value again and performs the determination process.

[0032] Next, the processing flow shown in Figure 4 will be explained. In Figure 4, it is assumed that processing starts from a state where the two higher-level packages 21 are operational. The starting state in Figure 4 is, for example, the state after the higher-level packages 21 have been started in Figure 3 (after step S106). The first traffic monitoring unit 241 monitors the amount of traffic flowing from the higher-level device 10 to the communication device 20 (step S107). If the amount of traffic exceeds the preset threshold "L1", "Y1" is recorded in the first stop column of the storage unit 23. If the amount of traffic does not exceed the preset threshold "L1", "N1" is recorded in the first stop column of the storage unit 23. If the amount of traffic does not exceed the threshold "L1" (step S108-NO), the second traffic monitoring unit 242 may proceed to the processing of step S111 of the determination unit 243 without operating, or the processing of step S109 may be executed.

[0033] At a minimum, if the traffic volume exceeds a preset threshold "L1" (step S108-YES), the second traffic monitoring unit 242 monitors the traffic for each lower package 22 (step S109). If the traffic volume exceeds a preset threshold "L2", "Y2" is recorded in the second stop column of the storage unit 23. In this case, the second stop column may be defined for each lower package 22. The second traffic monitoring unit 242 records a value in the second stop column corresponding to the lower package 22 being monitored. If the traffic volume does not exceed the preset threshold "L2", "N2" is recorded in the second stop column of the storage unit 23.

[0034] The determination unit 243 performs a determination process by referring to the values ​​recorded in the first stop column and the second stop column. If the value in the first stop column is "Y1" and the value in the second stop column of all lower packages 22 is "N2" (step S110-NO), the determination unit 243 does not output a pause instruction, and performs the determination process after referring to each value again at the next timing (for example, after a certain period of time has elapsed).

[0035] If the value of the first stop column is "N1" (step S108-NO), or if the value of the second stop column of at least one lower package 22 is "Y2" even if the value of the first stop column is "Y1" (step S110-YES), the determination unit 243 outputs a stop instruction to the package control unit 244 for the operating upper package 21 (step S111). The package control unit 244 transitions the operating upper package 21 to a paused state in response to the stop instruction (step S112). After that, the process returns to the start of the process shown in Figure 3 (step S113).

[0036] Figures 5 and 6 are flowcharts showing a second example of operation of the communication device 20. First, the processing flow shown in Figure 5 will be explained. The processing shown in Figure 5 is almost the same as the processing shown in Figure 3, but in Figure 5, the determination in step S204 is made based on whether or not frame discarding occurs in the second traffic, rather than whether or not the second traffic amount exceeds a threshold. Below, for the sake of clarity, the entire processing shown in Figure 5 will be explained. In Figure 5, it is assumed that processing starts from a state where one upper-level package 21 is in an operational state and the remaining upper-level package 21 is in a dormant state. The first traffic monitoring unit 241 monitors the amount of traffic flowing from the upper-level device 10 to the communication device 20 (step S201). If the traffic amount exceeds the preset threshold "L1", "Y1" is recorded in the first activation column of the storage unit 23. If the traffic amount does not exceed the preset threshold "L1", "N1" is recorded in the first activation column of the storage unit 23. If the traffic amount does not exceed the threshold "L1" (step S202-NO), the second traffic monitoring unit 242 does not need to operate.

[0037] At a minimum, if the traffic volume exceeds a preset threshold "L1" (step S202-YES), the second traffic monitoring unit 242 monitors the traffic for each lower package 22 (step S203). If frame discards occur in the second traffic, "Y2" is recorded in the second activation column of the storage unit 23. At this time, the second activation column may be defined for each lower package 22. The second traffic monitoring unit 242 records a value in the second activation column corresponding to the lower package 22 being monitored. If the traffic volume does not exceed a preset threshold "L2", "N2" is recorded in the second activation column of the storage unit 23.

[0038] The determination unit 243 performs a determination process by referring to the values ​​recorded in the first activation column and the second activation column. If the value of the first activation column is "Y1" and the value of the second activation column of all lower packages 22 is "N2" (step S204-NO), the determination unit 243 outputs an activation instruction to the package control unit 244 for the dormant upper package 21 (step S205). The package control unit 244 transitions the dormant upper package 21 to an operational state in response to the activation instruction (step S206).

[0039] If the value of the first activation column is "N1" (step S202-NO), or if the value of the first activation column is "Y1" but the value of the second activation column of at least one lower package 22 is "Y2" (step S204-YES), the determination unit 243 does not output an activation instruction, and instead, at the next timing (for example, after a certain period of time has elapsed), it refers to each value again and performs the determination process.

[0040] Next, the processing flow shown in Figure 6 will be explained. The processing shown in Figure 6 is almost the same as the processing shown in Figure 4, but in Figure 6, the determination in step S210 is based not on whether the amount of second traffic exceeds a threshold, but on whether frame discarding occurs in the second traffic. For the sake of clarity, the entire processing shown in Figure 6 will be explained below. In Figure 6, it is assumed that the processing starts from a state where the two higher-level packages 21 are operational. The starting state in Figure 6 is, for example, the state after the higher-level package 21 has been started in Figure 5 (after step S206). The first traffic monitoring unit 241 monitors the amount of traffic flowing from the higher-level device 10 to the communication device 20 (step S207). If the amount of traffic exceeds the preset threshold "L1", "Y1" is recorded in the first stop column of the storage unit 23. If the amount of traffic does not exceed the preset threshold "L1", "N1" is recorded in the first stop column of the storage unit 23. If the traffic volume exceeds the threshold "L1" (step S208-NO), the second traffic monitoring unit 242 may not operate and proceed to the processing of step S111 of the determination unit 243, or the processing of step S209 may be executed.

[0041] At a minimum, if the traffic volume exceeds a pre-set threshold "L1" (step S208-YES), the second traffic monitoring unit 242 monitors the traffic for each lower package 22 (step S209). If frame discards occur in the second traffic, "Y2" is recorded in the second stop column of the storage unit 23. At this time, the second stop column may be defined for each lower package 22. The second traffic monitoring unit 242 records a value in the second stop column corresponding to the lower package 22 being monitored. If no frame discards occur in the second traffic, "N2" is recorded in the second stop column of the storage unit 23.

[0042] The determination unit 243 performs determination processing by referring to the values recorded in the first stop column and the second stop column. When the value in the first stop column is "Y1" and the values in the second stop columns of all the lower-level packages 22 are "N2" (step S210 - NO), the determination unit 243 does not output a pause instruction, but refers to each value again at the next timing (for example, after a certain period of time) and then performs the determination processing.

[0043] When the value in the first stop column is "N1" (step S208 - NO), or even if the value in the first stop column is "Y1" and the value in the second stop column of at least one lower-level package 22 is "Y2" (step S210 - YES), the determination unit 243 outputs a stop instruction for the upper-level package 21 in the operating state to the package control unit 244 (step S211). The package control unit 244 transitions the upper-level package 21 in the operating state to the pause state according to the stop instruction (step S212). Then, the process returns to the start of the process shown in FIG. 5 (step S213).

[0044] FIGS. 7 and 8 are flowcharts showing a third operation example of the communication device 20. First, the process flow shown in FIG. 7 will be described. The process shown in FIG. 7 is substantially the same as the process shown in FIG. 3. In FIG. 7, a notification to the second traffic monitoring unit 242 is made as step S303. Also, in the process of step S305, the determination is made based on whether a transmission interruption frame for the upper-level package 21 is detected, rather than whether the second traffic volume exceeds the threshold value. Hereinafter, for the sake of completeness, the entire process shown in FIG. 7 will be described.

[0045] In Figure 7, it is assumed that processing begins with one upper-level package 21 in an operational state and the other upper-level package 21 in a dormant state. The first traffic monitoring unit 241 monitors the amount of traffic flowing from the upper-level device 10 to the communication device 20 (step S301). If the amount of traffic does not exceed the preset threshold "L1" (step S302-NO), the first traffic monitoring unit 241 executes step S301 at the next timing (for example, after a predetermined time has elapsed). On the other hand, if the amount of traffic exceeds the preset threshold "L1" (step S302-YES), the first traffic monitoring unit 241 notifies the second traffic monitoring unit 242 of a signal indicating "Y1" (step S303).

[0046] The second traffic monitoring unit 242 monitors the traffic for each lower package 22 (step S304). If a transmission interruption frame for the upper package 21 is detected within a predetermined time after the first traffic monitoring unit 241 notifies "Y1" (step S305-YES), the determination unit 243 and the package control unit 244 do not perform any special processing. A transmission interruption frame for the upper package 21 is a frame that indicates a request to the upper package 21 to interrupt the transmission of downlink frames. In this case, the first traffic monitoring unit 241 executes step S301 at the following timing.

[0047] On the other hand, if no transmission interruption frame for the upper-level package 21 is detected within a predetermined time after the first traffic monitoring unit 241 notifies "Y1" (step S305-NO), the determination unit 243 outputs a start command for the dormant upper-level package 21 to the package control unit 244 (step S306). The package control unit 244 transitions the dormant upper-level package 21 to an operational state in response to the start command (step S307).

[0048] Next, the process flow shown in FIG. 8 will be described. Assume that the process starts from a state where two upper-level packages 21 are in an operating state in FIG. 8. The start state in FIG. 8 is, for example, the state after the upper-level package 21 is activated in FIG. 7 (after step S307). The first traffic monitoring unit 241 monitors the traffic volume flowing from the upper-level device 10 to the communication device 20 (step S308). If the traffic volume does not exceed the preset threshold "L1" (step S309 - NO), the determination unit 243 executes the process of step S313. In this case, the first traffic monitoring unit 241 may notify the monitoring result to the determination unit 243. If the traffic volume exceeds the preset threshold "L1" (step S309 - YES), the first traffic monitoring unit 241 notifies the second traffic monitoring unit 242 of a signal indicating "Y1" (step S310).

[0049] The second traffic monitoring unit 242 monitors the traffic for each lower-level package 22 (step S311). If a transmission interruption frame for the upper-level package 21 is not detected within a predetermined time after "Y1" is notified from the first traffic monitoring unit 241 (step S312 - NO), the determination unit 243 and the package control unit 244 do not perform any particular processing. In this case, the first traffic monitoring unit 241 executes step S308 at the next timing.

[0050] On the other hand, if a transmission interruption frame for the upper-level package 21 is detected within a predetermined time after "Y1" is notified from the first traffic monitoring unit 241 (step S312 - YES), the determination unit 243 outputs a stop instruction for the operating upper-level package 21 to the package control unit 244 (step S313). The package control unit 244 transitions the operating upper-level package 21 to a suspended state in response to the stop instruction (step S314). Then, the process returns to the start of the process shown in FIG. 7 (step S315).

[0051] Figure 9 is a schematic diagram of an example hardware configuration of an information processing device 90 applied to this embodiment. The information processing device 90 comprises a processor 91, main memory 92, communication interface 93, auxiliary storage device 94, input / output interface 95, and internal bus 96. The processor 91, main memory 92, communication interface 93, auxiliary storage device 94, and input / output interface 95 are connected to each other via the internal bus 96 so as to be able to communicate with each other. The information processing device 90 may be applied to, for example, a communication device 20. In this case, for example, the storage unit 23 may be configured using the auxiliary storage device 94. Also, the control unit 24 may be configured using the processor 91 and the main memory 92.

[0052] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0053] 100...Communication system, 10...Higher-level device, 20...Communication device, 30...Lower-level device

Claims

1. A communication device connected to a higher-level device and a plurality of lower-level devices, comprising: a plurality of higher-level packages that communicate with the higher-level device; a plurality of lower-level packages that communicate with the lower-level devices; and a control unit that determines and controls whether to put each higher-level package into an operational state or a dormant state based on the downstream communication status received by the higher-level packages from the higher-level device and the downstream communication status received by each lower-level package.

2. The communication device according to claim 1, wherein the control unit determines to activate the same number or fewer higher-level packages as before if a predetermined state indicating a specific abnormal state occurs in the downstream communication status received by the lower-level package, which is a state in which a temporary increase in traffic from some specific users occurs.

3. The communication device according to claim 1 or 2, wherein the control unit determines to activate a larger number of upper-level packages if a predetermined abnormal state indicating a specific abnormal state in which a temporary increase in traffic from some specific users occurs in the downstream communication status received by the lower-level package, and the amount of traffic in the downstream communication status received by the upper-level package from the upper-level device exceeds a predetermined threshold.

4. A communication method performed by a communication device that is connected to a higher-level device and a plurality of lower-level devices, comprising a plurality of higher-level packages that communicate with the higher-level device and a plurality of lower-level packages that communicate with the lower-level devices, the communication method comprising a control step of determining and controlling whether to put each higher-level package into an operational state or a dormant state based on the downstream communication status received by the higher-level package from the higher-level device and the downstream communication status received by each lower-level package.

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