Communication device

Abstract

A communication device (1) comprises communication interface units (11, 12), a plurality of switch function units (151, 152), and a traffic assessment unit (14). The communication interface units (11, 12) transmit and receive frames to and from external devices. Each of the plurality of switch function units (151, 152) has a function for distributing the frames on the basis of the destination addresses of the received frames. Each of the plurality of switch function units (151, 152) is configured to be capable of individually turning on or off a power supply. The traffic assessment unit (14): ascertains a traffic amount for each user on the basis of user identification information held by the frames; determines whether to turn on the power supply of a powered-off switch function unit, among the plurality of switch function units, on the basis of the traffic amount for each user when the total traffic amount of the received frames exceeds a prescribed total traffic amount threshold value; and performs control to turn on the power supply of the switch function unit for which it is determined that the power supply is to be turned on, and turn off the power supply of the switch function unit for which it is determined that the power supply is not to be turned on. The traffic assessment unit (14) makes an assessment based on a criterion for assessing whether the traffic of only a specific small number of users has increased when the overall traffic volume exceeds the total traffic volume threshold value, determines that the power supply of the powered-off switch function unit is not to be turned on in cases where the traffic of only a specific small number of users has increased, and determines that the power supply of the powered-off switch function unit is to be turned on in other cases.

Description

communication equipment

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

[0002] It is desirable to be able to reduce power consumption based on appropriate conditions when operating a communication device. One method for reducing power consumption in a communication device is to turn on / off the power of some of the device's functions depending on the amount of traffic.

[0003] Patent Literature 1 (PTL 1) describes a technology for reducing power consumption of a communication device equipped with multiple switch function units (SWs) for allocating traffic. Specifically, the technology described in Patent Literature 1 is configured to reduce power consumption by suspending the function of the second switch function unit and suspending power supply to the second switch function unit when the traffic flowing from the opposing communication device is less than the processing performance of the first switch function unit. To achieve this reduction in power consumption, information on the volume of incoming traffic can be used as a condition for suspending the function of the second switch function unit. In other words, the communication device and the opposing communication device cooperate to control the device.

[0004] JP 2011-146874 A

[0005] However, the conventional technology has a problem: in order to achieve power saving in a communication device, a function for exchanging traffic control information between the communication device and an opposing communication device is required.

[0006] Furthermore, in the conventional technology, the on / off of the second switch function unit was determined based solely on the amount of incoming traffic. Therefore, in the conventional technology, when the amount of incoming traffic exceeds the processing capacity of the first switch function unit, it was impossible to determine whether the situation was caused by a single user using a large amount of traffic or by an increase in the total amount of traffic from multiple users. Therefore, in the conventional technology, even when the processing capacity of the first switch function unit is exhausted due to a single user using a large amount of traffic, the second switch function unit is controlled to be turned on. This is undesirable from the perspective of fairness in best-effort services and power saving in communication devices.

[0007] When a communication device is operated on the premise of best-effort service, it is desirable to have a situation in which many users can use the service fairly.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a communication device that can achieve power saving without exchanging information about traffic volume with an opposing communication device, and that can provide services fairly to many users.

[0009] [1] In order to solve the above problem, a communication device according to one aspect of the present invention comprises a communication interface unit that transmits and receives frames to and from an external device; a plurality of switch function units that have the function of distributing the frames based on the destination address of the received frames; and a traffic determination unit that grasps the traffic volume for each user based on user identification information in the frames, and when the total traffic volume of the received frames exceeds a predetermined total traffic volume threshold, determines whether to turn on the power of one of the plurality of switch function units that is powered off based on the traffic volume for each user, and controls the power on of the switch function unit that it has decided to power on and the power off of the switch function unit that it has decided not to power on, wherein each of the plurality of switch function units is configured to be able to be powered on or off individually, and when the total traffic volume exceeds the total traffic volume threshold, the traffic determination unit makes a determination based on a criterion for determining whether traffic from only a specific few users has increased, and if traffic from only a specific few users has increased, decides not to power on the switch function unit that is powered off, and otherwise decides to power on the switch function unit that is powered off.

[0010] [2] Furthermore, one aspect of the present invention is that in the communication device of [1] above, the frames have information indicating whether they are priority frames or best-effort frames, and when the total traffic volume exceeds the overall processing capacity of the switch function units that are currently powered on, the traffic determination unit discards at least some of the best-effort frames among the frames without passing them on to the switch function units that are currently powered on.

[0011] [3] Furthermore, one aspect of the present invention is a communication device according to [2] above, further comprising a marking unit that classifies the received best effort frames for each user into N classes, from class 1 to class N, in order of decreasing traffic volume for each user, based on (N-1) different distinction thresholds (where N is an integer of 2 or greater) related to traffic volume for each user, for distinguishing the best effort frames, and causes the best effort frames to have information representing each class.

[0012] [4] Furthermore, one aspect of the present invention is that in the communication device of [3] above, when discarding at least a portion of the best effort frames, the traffic determination unit gives priority to discarding the best effort frames of a class with a higher traffic volume per user.

[0013] According to the present invention, a communication device controls so that only necessary switch function units are powered on according to the total traffic volume, and even if the total traffic volume exceeds a predetermined total traffic volume threshold, switch function units that are powered off remain powered off if the increase in traffic from only a small number of specific users is the cause. In other words, if the increase in traffic from only a small number of specific users is the cause, more power than necessary is not consumed. This makes it possible to achieve both power saving and service fairness.

[0014] FIG. 1 is a block diagram showing a schematic functional configuration of a system including a communication device according to an embodiment of the present invention. FIG. 2 is a flowchart showing a processing procedure when a communication device according to an embodiment of the present invention operates. FIG. 3 is a schematic diagram showing a plurality of example patterns of traffic volume distribution by frame type in an embodiment of the present invention. FIG. 4 is a schematic diagram showing an example of management of traffic volume for each user by a communication device according to an embodiment of the present invention. FIG. 5 is a schematic diagram showing an example of traffic volume management according to prior art. FIG. 6 is a schematic diagram showing a first traffic pattern that is targeted when a traffic determination unit determines whether to power on an additional switch function unit in an embodiment of the present invention. FIG. 7 is a schematic diagram showing a second traffic pattern that is targeted when a traffic determination unit determines whether to power on an additional switch function unit in an embodiment of the present invention. FIG. 8 is a schematic diagram showing a third traffic pattern that is targeted when a traffic determination unit determines whether to power on an additional switch function unit in an embodiment of the present invention. FIG. 9 is a schematic diagram showing an example of a pattern of change in traffic volume in a first operation example of a communication device according to an embodiment of the present invention. FIG. 10 is a schematic diagram showing an example of a pattern of change in traffic volume in a second operation example of a communication device according to an embodiment of the present invention.

[0015] An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a communication device handles traffic including both priority frames and best-effort frames. That is, a communication device receives priority frames from an opposing communication device, assigns destinations to the priority frames, and transmits the priority frames to another opposing communication device. Also, a communication device receives best-effort frames from an opposing communication device, assigns destinations to the best-effort frames, and transmits the best-effort frames to another opposing communication device.

[0016] Here, a priority frame is a frame that should be transmitted with priority over a best-effort frame. Delivery of a priority frame may be guaranteed. A best-effort frame is a frame with a lower transmission priority than a priority frame, and depending on traffic conditions, it may be discarded en route before reaching its destination. Each frame has information in its header or elsewhere that indicates whether it is a priority frame or a best-effort frame. Traffic volume is managed by further distinguishing between multiple classes within best-effort frames. The multiple classes include, for example, green frames, yellow frames, and red frames.

[0017] The features of this embodiment are as follows. The communication device of this embodiment includes multiple switch function units. These multiple switch function units have the function of allocating traffic between the communication devices and are capable of individually controlling power on / off (controlling the operation / non-operation of each switch function unit). Furthermore, the marking unit performs marking on best-effort traffic among traffic input to the communication device based on whether the traffic volume exceeds a predetermined threshold. There may be multiple thresholds related to traffic volume. The traffic determination unit determines the marking of frames. Furthermore, the traffic determination unit performs determination on frames with a predetermined marking if the traffic volume exceeds the amount of traffic that can be processed by a switch function unit that is currently powered on (a switch function unit that is operating). If the number of users of frames with a predetermined marking is equal to or greater than a predetermined number and there is a powered-off switch function unit (a switch function unit that is not yet operating), the traffic determination unit powers on that switch function unit (activates that switch function unit). If the number of users of a frame bearing the specified marking is less than a specified number, or if there are no powered-off switch function units (switch function units that are not yet operating), the traffic determination unit discards the frame.

[0018] The communication device of this embodiment having the above features can improve the effect of power saving while maintaining the quality of best-effort traffic as a best-effort service.

[0019] 1 is a block diagram showing a schematic functional configuration of a system according to this embodiment. As shown in the figure, a system 300 includes a communication device 1, a communication device 201, and a communication device 202.

[0020] The communication device 1 communicates with external devices. That is, the communication device 1 transmits and receives frames including data to be transmitted and header information to and from the external devices. In the configuration shown in Fig. 1, the communication device 1 transmits and receives frames to and from the communication device 201 and the communication device 202.

[0021] Each of communication device 201 and communication device 202 is a communication device opposite communication device 1. Communication device 201 and communication device 202 may be of the same type as communication device 1, or may be of a different type. In the following description, communication device 1 receives frames from communication device 201. Communication device 1 sorts the received frames by destination and then transmits them toward communication device 202.

[0022] The internal configuration of the communication device 1 is as follows. That is, as shown in FIG. 1 , the communication device 1 includes a communication interface unit 11, a communication interface unit 12, a marking unit 13, a traffic determination unit 14, a switch function unit 151, and a switch function unit 152. Each of the functions of the communication device 1 can be realized using an electric circuit, an electronic circuit, or the like. Each of the functions of the communication device 1 may be provided with a means for at least temporarily storing data (such as a magnetic hard disk drive or semiconductor memory). Furthermore, as will be described later, at least some of the functions of the communication device 1 may be realized by a computer and a program.

[0023] The communication interface units 11 and 12 each function as an interface for communicating with a corresponding communication device. Specifically, the communication interface unit 11 has an interface function for communicating with the corresponding communication device 201. The communication interface unit 12 has an interface function for communicating with the corresponding communication device 202. In other words, the communication interface units 11 and 12 send and receive frames to and from external devices.

[0024] The communication interface unit 11 receives a frame from an external device (for example, the communication device 201 ) and passes the received frame to the marking unit 13 .

[0025] The marking unit 13 performs marking to determine the traffic status based on multiple preset thresholds. The thresholds are values ​​related to the traffic volume per user, and are (N-1) in number, such as a first threshold, a second threshold, ..., and an (N-1)th threshold. These thresholds are sometimes referred to as "distinguishing thresholds." Note that the first threshold < the second threshold < ... < the (N-1)th threshold. In this case, the marking unit 13 distinguishes and marks each of a user's frames based on the user's traffic volume. That is, the marking unit 13 distinguishes between frames whose traffic volume falls within a range equal to or less than the first threshold, frames whose traffic volume falls within a range exceeding the first threshold and equal to or less than the second threshold, frames whose traffic volume falls within a range exceeding the second threshold and equal to or less than the third threshold, ..., and frames whose traffic volume falls within a range exceeding the (N-1)th threshold. Note that the marking unit 13 performs traffic volume determination and marking individually for each user. That is, at a certain point in time, there may be a situation where the traffic volume of user 1 exceeds the first threshold and the traffic volume of user 2 is equal to or less than the first threshold.

[0026] The user is identified by a user ID (user identification information). The header of the frame that the marking unit 13 receives from the communication interface unit 11 includes information about the user ID.

[0027] For example, in the case where there are two thresholds, the marking unit 13 may mark frames as follows: That is, for a certain user, the marking unit 13 may mark frames that belong to an area where the traffic volume is equal to or less than a first threshold as green frames, frames that belong to an area where the traffic volume exceeds the first threshold and is equal to or less than a second threshold as yellow frames, and frames that belong to an area where the traffic volume exceeds the second threshold as red frames.

[0028] That is, the marking unit 13 classifies the received best effort frames for each user into N classes, from class 1 to class N, in order from the user with the least amount of traffic, based on (N-1) different classification thresholds (where N is an integer of 2 or greater) related to the traffic volume for each user for classifying best effort frames. The marking unit 13 adds information representing each class to the best effort frame. That is, the marking unit 13 either leaves the information representing the class as is with the original default value, or rewrites it to represent an appropriate class.

[0029] In this embodiment, an example will be described in which best-effort frames are classified into three classes: green frames, yellow frames, and red frames. In this case, N=3, and frames are classified and marked using two (N-1) "classification thresholds," a first threshold and a second threshold.

[0030] The traffic determination unit 14 determines the marking status for each user based on the marking performed by the marking unit 13. Furthermore, the traffic determination unit 14 controls whether to operate each of the multiple switch function units (151 and 152) (whether to power on or off) based on the marking status for each user. Furthermore, the traffic determination unit 14 may discard traffic that should be discarded. For example, the traffic determination unit 14 may discard some of the best-effort frames when the processing capacity of a switch function unit that is powered on and in operation is exceeded.

[0031] Specifically, the traffic determination unit 14 grasps the traffic volume for each user based on the user ID (user identification information) included in the received frame. Furthermore, when the total traffic volume of the received frames exceeds a predetermined total traffic volume threshold, the traffic determination unit 14 determines whether to power on a switch function unit among the multiple switch function units (switch function units 151 and 152) that is currently powered off, based on the traffic volume for each user. The traffic determination unit 14 controls the power on of the switch function unit that it has determined to power on. Furthermore, the traffic determination unit 14 controls the power off of the switch function unit that it has determined not to power on.

[0032] When the total traffic volume flowing into the communication device 1 exceeds the total traffic volume threshold, the traffic determination unit 14 makes a determination based on a criterion for determining whether the increase in traffic from only a specific small number of users is due to the increase in traffic. If the increase in traffic from only a specific small number of users is due to the increase in traffic, the traffic determination unit 14 decides not to turn on the power of the switch function unit that is currently powered off. In other cases, the traffic determination unit 14 decides to turn on the power of the switch function unit that is currently powered off.

[0033] When the total traffic volume exceeds the total processing capacity of the switch function units that are currently (at that time) powered on, the traffic determination unit 14 may discard at least a portion of the best effort frames among the frames it receives without passing them on to the switch function units that are powered on.

[0034] When discarding at least a portion of best-effort frames, the traffic determination unit 14 may discard best-effort frames from the class with the highest traffic volume for each user. In other words, if three classes are used: green frames (lowest traffic volume), yellow frames (medium traffic volume), and red frames (highest traffic volume), the traffic determination unit 14 first discards red frames, then yellow frames, and finally green frames, so that the traffic volume fits within the processing capacity of the switch function unit. This maintains fairness among users. In other words, for example, in a situation where there are users who use red frames and users who do not use red frames, the red frames of the former users are discarded first.

[0035] Each of the switch function units 151 and 152 has the function of directing traffic received from the communication device 201 to the corresponding communication destination of the communication device 202. The header of each frame contains information on the source address and destination address. The switch function units 151 and 152 refer to this address information to distribute frames. Each of the switch function units 151 and 152 sends the distributed frames to an external device by passing them to the communication interface unit 12. In other words, the switch function units 151 and 152 are multiple switch function units that have the function of distributing frames received by the communication interface unit 11 based on the destination address of the frames.

[0036] The switch function units 151 and 152 are configured to be able to be individually powered on (operating) or powered off (not operating). That is, the traffic determination unit 14 can control the power on or power off state of the switch function units 151 and 152.

[0037] The communication interface unit 12 transmits the frames passed from the switch function unit 151 and the switch function unit 152 to the devices (for example, the communication device 202) at the respective destination addresses.

[0038] 2 is a flowchart showing the processing procedure when the communication device 1 operates. The following description will be given with reference to this flowchart.

[0039] The default state when the communication device 1 starts operation is a state in which the switch function unit 151 is operating (i.e., power is on) and the switch function unit 152 is not operating (i.e., power is off).

[0040] In step S1, the communication device 1 determines whether or not to continue operation of the device. For example, if a command to shut down the communication device 1 is input from outside, the communication device 1 will not continue operation. If it is determined that operation of the device will continue (step S1: YES), the process proceeds to the next step S2. If it is determined that operation of the device will not continue (step S1: NO), the entire process of this flowchart ends.

[0041] In step S2, the communication device 1 measures the traffic received from the opposing communication device (communication device 201 in FIG. 1). In this step, the communication device 1 measures the total amount of traffic received by the communication device 1.

[0042] Next, in step S3, the traffic determination unit 14 determines whether the traffic measured in step S3 is equal to or greater than a predetermined threshold. The threshold here is a reference value for determining whether to power on the switch function unit 152 (second switch function unit). In other words, this threshold is a reference value for determining the upper limit of processing by the switch function unit 151 (first switch function unit) alone. Alternatively, this threshold may be a reference for determining whether the upper limit of processing by the switch function unit 151 (first switch function unit) alone is approaching. If the measured traffic is equal to or greater than the threshold (step S3: YES), the process proceeds to step S4. If the measured traffic is less than the threshold (step S3: NO), the process proceeds to step S6.

[0043] If the process proceeds to step S4, in this step, the traffic determination unit 14 determines whether the traffic increase at that time is due to only a specific user. In other words, it determines whether the traffic exceeding the threshold determined in step S3 is due solely to traffic from a specific user. Note that when making this determination, the traffic determination unit 14 refers to the user ID in the received frame. If the traffic increase is due solely to a specific user (step S4: YES), the process proceeds to step S6. If the traffic increase is not due solely to a specific user (step S4: NO), the process proceeds to step S5.

[0044] When the process proceeds to step S5, in this step, the traffic determination unit 14 controls to turn on the power of the switch function unit 152 (second switch function unit). This control causes the switch function unit 152 (second switch function unit) to start operating. In other words, both the switch function unit 151 (first switch function unit) and the switch function unit 152 (second switch function unit) are operating in the communication device 1, and the communication device 1's ability to handle traffic is improved. In other words, the communication device 1 is able to process a larger amount of traffic. After the process of step S5 is completed, the process returns to step S1.

[0045] When the process proceeds to step S6, the traffic determination unit 14 controls the switch function unit 152 (second switch function unit) to remain powered off. This control keeps the switch function unit 152 (second switch function unit) inactive. In other words, in the communication device 1, only the switch function unit 151 (first switch function unit) continues to perform the process of distributing frames according to their destinations. After the process of step S6 is completed, the process returns to step S1.

[0046] Figure 3 is a schematic diagram showing examples of several patterns of traffic volume distribution by frame type. In this figure, the vertical axis corresponds to traffic volume. Patterns A, B, and C shown in this figure are examples of traffic volumes that include both priority frames and best-effort frames. Note that best-effort frames are either green frames, yellow frames, or red frames.

[0047] Pattern A is a traffic pattern that includes only priority frames and green frames. Pattern B is a traffic pattern that includes only priority frames, green frames, and yellow frames. Pattern C is a traffic pattern that includes priority frames, green frames, yellow frames, and red frames. Note that the green frames in each pattern shown in Figure 3 include green frames used by multiple users. Also, the yellow frames in Figure 3 include yellow frames used by multiple users. Also, the red frames in Figure 3 include red frames used by multiple users.

[0048] 3, when the total traffic volume approaches the upper traffic volume limit or the traffic volume threshold for determination, the traffic determination unit 14 determines whether to activate a switch function unit that has not been operating (a switch function unit that has been powered off). Unless only a specific small number of users (for example, one user) are pushing up the total traffic volume, the traffic determination unit 14 performs control to activate a switch function unit that has not been operating (a switch function unit that has been powered off).

[0049] 4 is a schematic diagram showing an example of management of the traffic volume for each user by the communication device 1. In the figure, the vertical axis corresponds to the traffic volume.

[0050] As mentioned above, traffic transmitted and received between communication device 1 and communication devices 201 and 202 may include both priority frames and best-effort frames.

[0051] To achieve best-effort service, the communication device 1 operates according to the following mechanism. That is, the frame header is designed to have information for distinguishing whether the frame is a green frame, a yellow frame, or a red frame. Here, the default is a green frame. Note that a number of predetermined bits at fixed positions within the frame, for example, are the information for distinguishing these frames.

[0052] The marking unit 13 stores in advance a first threshold and a second threshold for traffic usage. These first and second thresholds are thresholds related to the traffic volume for each user and can be set. Note that the second threshold is assumed to be larger than the first threshold.

[0053] If the traffic volume per user (volume of transmitted data per unit time) does not exceed the first threshold, the marking unit 13 marks the frame received by the communication interface unit 11 as a green frame (default setting). If the traffic volume per user exceeds the first threshold but does not reach the second threshold, the marking unit 13 rewrites the header of the frame received by the communication interface unit 11 to mark it as a yellow frame. Furthermore, if the traffic volume per user exceeds the second threshold, the marking unit 13 rewrites the header of the frame to mark it as a red frame.

[0054] By distinguishing between green frames, yellow frames, and red frames in this way, the communication device 1 can discard some frames when the total traffic exceeds the upper limit of the communication interface. Specifically, when the total traffic exceeds the upper limit, the red frames are discarded first, and then the yellow frames, thereby realizing a best-effort service.

[0055] A feature of this embodiment is that it distinguishes the type of frame for each individual user. In other words, the traffic determination unit 14 has the function of managing a combination of user ID information in the frame header and information indicating the frame type (green, yellow, red). In other words, the traffic determination unit 14 manages the frame communication speed while monitoring the traffic volume for each user.

[0056] The example shown in FIG. 4 illustrates how frames are distinguished when user 1 and user 2 communicate at 4 Gbps (gigabits per second). In this example, the first threshold is 2 Gbps and the second threshold is 3 Gbps. For user 1, frames that do not reach the first threshold of 2 Gbps are treated as green frames. Frames that exceed the first threshold of 2 Gbps but do not reach the second threshold of 3 Gbps are treated as yellow frames. Frames that exceed the second threshold of 3 Gbps are treated as red frames. For user 2, as with user 1, frames that do not reach the first threshold are treated as green frames. Frames that exceed the first threshold but do not reach the second threshold are treated as yellow frames. Frames that exceed the second threshold are treated as red frames.

[0057] By managing user IDs and frame types in combination, the traffic determination unit 14 first fairly discards the red frames of user 1 and the red frames of user 2 when the total traffic volume exceeds the upper limit. If the total traffic volume still exceeds the upper limit even after discarding all red frames of both users, the traffic determination unit 14 then fairly discards the yellow frames of user 1 and the yellow frames of user 2.

[0058] In other words, the marking unit 13 classifies the received best-effort frames for each user into N classes, from Class 1 to Class N, in order of decreasing traffic volume for each user, based on (N-1) different distinction thresholds (where N is an integer greater than or equal to 2) related to the traffic volume for each user, and assigns information representing each class to the best-effort frames. For example, N may be 3, but N may also be any positive integer. When discarding at least some of the best-effort frames, the traffic determination unit 14 prioritizes discarding best-effort frames from classes with higher traffic volumes for each user. In other words, in the above example, red frames are discarded first, and if the traffic volume is still too high, yellow frames are discarded next. If the traffic volume is still too high, green frames may be discarded next. In this way, this embodiment enables power saving while maintaining fairness among users, thereby realizing best-effort services.

[0059] FIG. 5 is a schematic diagram illustrating an example of traffic volume management according to conventional technology, for comparison with this embodiment. In the diagram, the vertical axis corresponds to traffic volume. In the example of FIG. 5, it is assumed that user 1 and user 2 each attempt to communicate at 4 Gbps. Note that, with respect to the traffic volume for each user, the first threshold is 2 Gbps and the second threshold is 3 Gbps. Note that, in this example, the traffic of priority frames is 3 Gbps. The upper limit of the communication interface unit is 10 Gbps.

[0060] In the case of Figure 5, of the 4 Gbps traffic transmitted by user 1, the portion that does not reach the first threshold is a green frame. The portion that exceeds the first threshold but does not reach the second threshold is a yellow frame. The portion that exceeds the second threshold is a red frame. The same is true for the 4 Gbps traffic transmitted by user 2, where the portion that does not reach the first threshold is a green frame. The portion that exceeds the first threshold but does not reach the second threshold is a yellow frame. The portion that exceeds the second threshold is a red frame. Priority frames are transmitted with priority over green, yellow, and red frames.

[0061] In this case, the 3 Gbps priority frames, 4 Gbps user 1 frames, and 4 Gbps user 2 frames add up to a total of 11 Gbps. In other words, traffic exceeds the upper limit of the communication interface. In such a case, even with conventional technology, frames are discarded based on frame type. That is, the 3 Gbps priority frames, the total of 4 Gbps green frames, and the 2 Gbps yellow frames add up to 9 Gbps, and these frames are not discarded. Then, by discarding 1 Gbps of the 2 Gbps red frames, control is achieved to prevent the upper limit of the communication interface from being exceeded. However, in conventional technology, management is performed based on frame type (priority frames, green frames, yellow frames, red frames), but the user is not taken into consideration. In other words, which 1 Gbps red frames are discarded out of the total 2 Gbps red frames is randomly determined. In other words, frame discarding is not performed with user ID in mind. Therefore, unfairness may occur among users.

[0062] 6, 7, and 8 are schematic diagrams showing multiple traffic patterns that the traffic determination unit 14 considers when determining whether to activate the switch function unit 152 (second switch function unit). In each of FIGS. 6, 7, and 8, the vertical axis corresponds to traffic volume. The traffic determination unit 14 uses a condition based on the volume of red frames, yellow frames, and green frames for each user ID as a condition for determining whether to activate the switch function unit 152 (second switch function unit). This allows the communication device 1 to achieve both service fairness and power saving.

[0063] 6 shows a first traffic pattern. In the situation shown in the figure, the overall amount of communication traffic has reached (or is approaching) the upper limit of communication capacity. In this first pattern, in addition to priority traffic, green frames from users 1 to 5 account for the traffic almost equally. In this case, the traffic determination unit 14 controls the operation of the switch function unit 152 (second switch function unit) to increase the processing capacity of the switch function of the communication device 1 in this situation. Specifically, for example, the traffic determination unit 14 turns on the power of the switch function unit 152 (second switch function unit).

[0064] FIG. 7 illustrates a second traffic pattern. In the illustrated situation, the overall communication traffic volume has reached (or is approaching) the upper limit of communication capacity. In this second pattern, in addition to priority traffic, green frames, yellow frames, and red frames for users 1 through 3 account for the overall traffic. In other words, red traffic (traffic exceeding the second threshold) is flowing in from users 1 through 3. In this case, a specific user (e.g., one user) is not using a large amount of traffic, and the traffic per user is roughly equal. Therefore, to increase the processing capacity of the switch function of the communication device 1, control is performed to activate the switch function unit 152 (second switch function unit). Specifically, for example, the traffic determination unit 14 turns on the power of the switch function unit 152 (second switch function unit).

[0065] FIG. 8 illustrates a third traffic pattern. In the illustrated situation, the overall communication traffic volume has reached (or is approaching) the upper limit of communication capacity. In this third pattern, in addition to the priority traffic, the overall traffic is dominated by green, yellow, and red frames from user 1 alone. In other words, unlike the cases of FIGS. 6 and 7, the example of FIG. 8 shows that only one user is using a large amount of traffic. In this case, the communication device 1 does not increase the processing capacity of the switch function. In other words, the traffic determination unit 14 controls the switch function unit 152 (second switch function unit) to remain inactive. Specifically, for example, the traffic determination unit 14 keeps the power of the switch function unit 152 (second switch function unit) off.

[0066] As described in the above example, when determining whether to power on or off the switch function unit 152 (second switch function unit), the communication device 1 determines whether the traffic volume of only a specific few users is large, in addition to whether the overall traffic volume is equal to or greater than a threshold. By setting such criteria, if only a few users are transmitting a large amount of traffic, the traffic determination unit 14 leaves the power of the switch function unit 152 (second switch function unit) off. In other words, the traffic determination unit 14 does not increase the number of operating switch functions of the communication device 1. On the other hand, if the overall traffic volume is equal to or greater than the threshold and many users are transmitting traffic at the same level, the traffic determination unit 14 turns on the power of the switch function unit 152 (second switch function unit). In other words, the traffic determination unit 14 increases the number of operating switch functions of the communication device 1. This prevents a deterioration in service quality.

[0067] As described above, the communication device 1 has the function of distinguishing between red frames, yellow frames, and green frames for each user in order to determine whether to activate more switch functions. This allows the communication device 1 to maintain a power-saving operating state without degrading the overall quality of best-effort service.

[0068] On the other hand, while prior art technologies were configured to control the power on / off of some switch functions based on the overall traffic volume, they did not control the power on / off based on the traffic volume of each user. Therefore, prior art communication devices could not distinguish whether an increase in overall traffic volume was due to a small number of specific users (e.g., one user) or an overall increase in traffic from many users. In other words, prior art technologies could not distinguish between the situations shown in Figures 6 and 7 and the situation shown in Figure 8. In other words, prior art technologies required power to keep many switch functions running even when a large amount of traffic continued from a single user, which was undesirable in terms of balancing power saving and service quality.

[0069] As described above, when the total traffic volume flowing into the communication device 1 exceeds the total traffic volume threshold, the traffic determination unit 14 determines, based on a predetermined criterion, whether the increase in traffic is due to only a small number of specific users. Examples of the determination criterion are described below.

[0070] Criterion Example 1: When the number of users generating traffic is N or less, the traffic determination unit 14 determines that the traffic increase is due to only a small number of specific users. In other cases, the traffic determination unit 14 determines that the increase is not due to an increase in traffic due to only a small number of specific users, but is due to traffic from a large number of users. N is a positive integer and may be a configurable value.

[0071] Criterion Example 2: The traffic determination unit 14 determines that the traffic of only a small number of specific users has increased if the total traffic of the top N users in terms of traffic volume accounts for S% or more of the total traffic. In other cases, the traffic determination unit 14 determines that the increase in traffic is not due to an increase in traffic of only a small number of specific users, but is due to traffic from a large number of users. Here, N is a positive integer. Also, S is a real number greater than or equal to 0 and less than or equal to 100. Note that N and S may be settable values.

[0072] Criterion Example 3: The traffic determination unit 14 determines that the traffic of only a specific few users has increased if the total traffic of the red frames of the top N users in terms of traffic volume accounts for S% or more of the total traffic. In other cases, the traffic determination unit 14 determines that the increase in traffic is not due to an increase in traffic of only a specific few users, but is due to traffic from a large number of users. Here, N is a positive integer. Also, S is a real number greater than or equal to 0 and less than or equal to 100. Note that N and S may be settable values.

[0073] Criterion Example 4: The traffic determination unit 14 determines that the traffic of only a small number of specific users has increased if the total traffic of the red frames and yellow frames of the top N users in terms of traffic volume accounts for S% or more of the total traffic. In other cases, the traffic determination unit 14 determines that the increase in traffic is not due to the increase in traffic of only a small number of specific users, but is due to traffic from a large number of users. Here, N is a positive integer. Also, S is a real number greater than or equal to 0 and less than or equal to 100. Note that N and S may be configurable values.

[0074] Criterion Example 5: The traffic determination unit 14 calculates the variance of the traffic volume for each user, and determines that the traffic of only a specific few users has increased if there are N or more users whose traffic volume is above average and whose variance is D or greater. In other cases, the traffic determination unit 14 determines that the increase in traffic is not due to the increase in traffic of only a specific few users, but is due to the traffic of a large number of users. Here, N is a positive integer. Also, D is a positive real number. Note that N and D may be settable values.

[0075] Criterion Example 6: The traffic determination unit 14 calculates the variance value of the traffic volume of red frames for each user, and determines that the traffic of only a specific few users has increased if there are N or more users whose traffic volume is above average and whose variance value is D or greater. In other cases, the traffic determination unit 14 determines that the increase in traffic is not due to an increase in traffic of only a specific few users, but is due to traffic from a large number of users. Here, N is a positive integer. Also, D is a positive real number. Note that N and D may be settable values.

[0076] Criterion Example 7: The traffic determination unit 14 calculates the variance value of the traffic volume combining the red frames and yellow frames for each user, and determines that the traffic of only a specific few users has increased if there are N or more users whose traffic volume is above average and whose variance value is D or greater. In other cases, the traffic determination unit 14 determines that the increase in traffic is not due to the increase in traffic of only a specific few users, but is due to the traffic of a large number of users. Here, N is a positive integer. Also, D is a positive real number. Note that N and D may be configurable values.

[0077] In each of the above criteria examples 2, 3, and 4, the traffic determination unit 14 may make a determination using a criterion of "the top R% of users (rounded to the nearest whole number) in terms of traffic volume" instead of "the top N users in terms of traffic volume." In this case, R is a real number greater than or equal to 0 and less than or equal to 100. R may be a configurable value.

[0078] Next, several examples of the operation of the communication device 1 will be described.

[0079] 9 is a schematic diagram showing an example of a pattern of change in traffic volume in the first operation example. In the figure, the vertical axis corresponds to the traffic volume. In this example, the traffic volume changes from a first state to a second state.

[0080] In the first state, only priority frames and user 1's green frames are present. In this first state, only the switch function unit 151 (first switch function unit) is operating. Furthermore, the total traffic volume, which is the combination of priority frames and user 1's green frames, is below the total traffic volume threshold indicated by the dashed line. Therefore, the traffic determination unit 14 keeps the power supply of the switch function unit 152 (second switch function unit) turned off, and controls the switch function unit 151 (first switch function unit) to process traffic only. This reduces the power consumption of the switch function unit 152 (second switch function unit).

[0081] In the second state, in addition to the traffic in the first state, users 2 through 5 each transmit a green frame. As a result, the total traffic volume, including the priority frames and the green frames from users 1 through 5, exceeds the total traffic volume threshold indicated by the dashed line. The traffic determination unit 14 also reads the user IDs written in each frame and performs a determination based on the traffic volume for each user ID. In the second state, five users are transmitting traffic at roughly equal rates. In other words, the traffic determination unit 14 determines that the increase in traffic volume is due to a large number of users, rather than a small number of specific users. Based on this determination result, the traffic determination unit 14 powers on the switch function unit 152 (second switch function unit) and increases the overall processing capacity of the switch function unit 151 (first switch function unit) and the switch function unit 152 (second switch function unit). This reduces the discarding of best-effort traffic and prevents a deterioration in service quality.

[0082] In other words, since the traffic determination unit 14 has the function of making a determination based on the traffic volume for each user, it is possible to improve the power saving effect while maintaining the quality of a best-effort service, unlike conventional technology.

[0083] 10 is a schematic diagram showing an example of a pattern of change in traffic volume in the second operation example. In the figure, the vertical axis corresponds to the traffic volume. In this example, the traffic volume changes from a first state to a second state.

[0084] In the first state, similar to the first state in FIG. 9 , only priority frames and user 1's green frames are present. In this first state, only the switch function unit 151 (first switch function unit) is operating. Furthermore, the total traffic volume, which is the sum of priority frames and user 1's green frames, is below the total traffic volume threshold indicated by the dashed line. Therefore, the traffic determination unit 14 keeps the power supply of the switch function unit 152 (second switch function unit) turned off, and controls the switch function unit 151 (first switch function unit) to process traffic only. This reduces the power consumption of the switch function unit 152 (second switch function unit).

[0085] In the second state, the traffic volume of user 1 has increased compared to the first state. In other words, due to the transmission of user 1's yellow and red frames, the overall traffic volume has increased and exceeded the overall traffic volume threshold indicated by the dashed line. Note that even in the second state, there is no traffic from users other than user 1. The traffic determination unit 14 reads the user IDs written in each frame and performs a determination based on the traffic volume for each user ID. The traffic determination unit 14 determines that the increase in traffic in the second state is due to a single user (user 1) sending a large amount of traffic. In other words, the traffic determination unit 14 determines that the increase in traffic in the second state is not due to use by many users. Based on this determination result, the traffic determination unit 14 keeps the power supply of the switch function unit 152 (second switch function unit) turned off. In other words, the switch function unit 152 (second switch function unit) remains inactive, and only the switch function unit 151 (first switch function unit) continues processing. In this situation, traffic exceeding the processing capacity of the switch function unit 151 (first switch function unit) is discarded. That is, part of the red frames of user 1 shown in FIG.

[0086] Since this is a best-effort service, discarding some of User 1's red frames does not affect the quality of service. The information contained in the discarded frames may be recovered by retransmission or other means in a higher layer communication protocol. For example, the user device may have the function of retransmitting discarded data as needed.

[0087] In other words, since the traffic determination unit 14 has the function of making a determination based on the traffic volume for each user, it is possible to improve the power saving effect while maintaining the quality of a best-effort service, unlike conventional technology.

[0088] The above describes the process in which the traffic determination unit 14 determines and controls whether to power on the switch function units that were powered off at the time when the total traffic volume flowing into the communication device 1 increases. Conversely, if the total traffic volume flowing into the communication device 1 decreases over time, the traffic determination unit 14 may determine and control to power off the switch function units that were powered on as appropriate, depending on the changed traffic volume. This allows power saving when the total traffic volume decreases. In other words, the communication device 1 can control to increase or decrease the number of switch function units that are powered on, depending on the increase or decrease in traffic volume.

[0089] The communication device 1 of the present embodiment can be realized by a computer and a program. The program can be recorded on a recording medium or provided via a network. In other words, a program for causing a computer to function as the communication device 1 can be implemented.

[0090] FIG. 11 is a block diagram showing an example of the internal configuration of a computer when the communication device 1 of this embodiment is realized by a computer. As shown in the figure, the computer includes a central processing unit 901, a RAM 902, an input / output port 903, input / output devices 904 and 905, and a bus 906. The computer itself can be realized using existing technology. The central processing unit 901 executes instructions contained in a program read from the RAM 902 or the like. In accordance with each instruction, the central processing unit 901 writes data to the RAM 902, reads data from the RAM 902, and performs arithmetic and logical operations. The RAM 902 stores data and programs. Each element included in the RAM 902 has an address and can be accessed using the address. RAM stands for "random access memory." The input / output port 903 is a port through which the central processing unit 901 exchanges data with external input / output devices. The input / output devices 904 and 905 exchange data with the central processing unit 901 via the input / output port 903. The bus 906 is a common communication path used within the computer. For example, the central processing unit 901 reads and writes data from and to the RAM 902 via the bus 906. Also, for example, the central processing unit 901 accesses the input / output port 903 via the bus 906.

[0091] At least some of the functions of the communication device 1 can be implemented by a computer and a program. In this case, the program for implementing the functions may be recorded on a computer-readable recording medium and then loaded and executed by a computer system. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, CD-ROMs, DVD-ROMs, and USB memory, as well as storage devices such as hard disks built into computer systems. In other words, a "computer-readable recording medium" may be a non-transitory computer-readable recording medium. Furthermore, the term "computer-readable recording medium" may also include media that temporarily and dynamically store programs, such as communication lines used when transmitting programs over networks like the Internet or telephone lines, or media that store programs for a certain period of time, such as volatile memory within the computer systems that serve as the server or client in such cases. The program may be designed to implement some of the functions described above, or may be capable of implementing the functions described above in combination with a program already stored in the computer system.

[0092] As described above, the communication device 1 of this embodiment includes a traffic determination unit 14, which determines the usage status (traffic volume) of each user for traffic flowing from an opposing communication device, located before the switch function units (151, 152). This allows the traffic determination unit 14 to determine whether to activate an additional switch function unit based on the traffic volume for each user when the overall traffic volume increases. In other words, the traffic determination unit 14 determines whether the overall traffic volume across many users is increasing or whether the traffic volume for a specific few users (e.g., one user) is increasing. In other words, it can determine whether to power on the additional switch function unit based on the determination result of the traffic determination unit 14. This makes it possible to achieve both service fairness and power saving in best-effort services.

[0093] Although the embodiment has been described above, the present invention can also be carried out in the following modified examples.

[0094] [Modification] In the communication device 1 of the embodiment, the two switch function units (151, 152) are individually controlled to be powered on or off. As a modification, the number of switch function units that can be individually controlled to be powered on or off may be three or more. In such a case, when the processing capacity of an active switch function unit is about to be exceeded at a certain point in time (when the traffic volume exceeds a threshold for this determination), the traffic determination unit 14 makes a determination based on the traffic volume for each user, as in the present embodiment, and determines whether to power on an additional switch function unit.

[0095] The present invention can be used, for example, in devices for realizing communication services, but the scope of use of the present invention is not limited to the examples given here.

[0096] REFERENCE SIGNS LIST 1 Communication device 11 Communication interface unit 12 Communication interface unit 13 Marking unit 14 Traffic determination unit 151 Switch function unit (first switch function unit) 152 Switch function unit (second switch function unit) 201, 202 Communication device 300 System

Claims

1. A communications device comprising: a communications interface unit that transmits and receives frames to and from an external device; a plurality of switch function units that have the function of distributing the frames based on the destination address of the received frames; and a traffic determination unit that grasps the traffic volume for each user based on user identification information in the frames, and when the total traffic volume of received frames exceeds a predetermined total traffic volume threshold, decides whether to power on any of the plurality of switch function units that are powered off based on the traffic volume for each user, and controls the device to turn on the power of any switch function unit that it has decided to power on, and to keep off any switch function unit that it has decided not to power on; wherein each of the plurality of switch function units is configured to be able to turn on or off its power individually, and the traffic determination unit makes a determination based on criteria for determining whether or not the increase in traffic from only a specific small number of users is due to an increase in traffic when the total traffic volume exceeds the total traffic volume threshold, and decides not to power on any of the switch function units that are powered off if the increase in traffic from only a specific small number of users is due to an increase in traffic, and decides to power on any other switch function unit that it has decided not to power on.

2. The communication device according to claim 1, wherein the frames have information indicating whether they are priority frames or best-effort frames, and the traffic determination unit discards at least some of the best-effort frames among the frames without passing them on to the switch function units that are currently powered on if the total traffic volume exceeds the total processing capacity of the switch function units that are currently powered on.

3. The communication device according to claim 2, further comprising a marking unit that classifies the received best effort frames for each user into N classes, from class 1 to class N, in order of decreasing traffic volume for each user, based on (N-1) different distinction thresholds (where N is an integer greater than or equal to 2) related to traffic volume for each user, for distinguishing the best effort frames, and assigns information representing each class to the best effort frames.

4. The communication device according to claim 3, wherein when discarding at least some of the best-effort frames, the traffic determination unit gives priority to discarding the best-effort frames of a class with a larger traffic volume for each user.

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