Calculation device

Abstract

Provided is a calculation device that calculates a buffer amount for each queue in a communication device that performs priority control using a plurality of queues, the calculation device comprising: a first buffer calculation unit that calculates a buffer amount for each queue using a first buffer calculation method on the basis of the number of users who use a service and usage information of the service used by the users; a second buffer calculation unit that calculates a buffer amount for each queue using a second buffer calculation method, which is a calculation method different from the first buffer calculation method, on the basis of the number of users who use the service and the usage information of the service used by the users; and a buffer amount determination unit that determines a buffer amount to be set for a buffer of each queue of the communication device on the basis of the buffer amount for each queue calculated by the first buffer calculation unit and the buffer amount for each queue calculated by the second buffer calculation unit.

Description

Calculation device

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

[0002] Conventionally, communication devices perform priority control using a buffer equipped with multiple queues. FIG. 6 is a diagram showing the flow of priority control in a communication device. As shown in FIG. 6, the buffer of the communication device will be described as having four queues. When multiple types of traffic F1 to F4 are input to the communication device, a classification unit 1 provided inside the communication device sorts the input traffic into queues corresponding to each priority class. FIG. 6 shows four multiple queues: EF (Expedited Forwarding) class, AF (Assured Forwarding) 4 class, AF1 class, and BE (Best Effort) class. The EF class has the highest priority, and the BE class has the lowest priority.

[0003] When a communication device performs priority control using the SPQ (Strict Priority Queuing) method, the output unit 2 provided inside the communication device outputs traffic to a transmission queue in order from the queue with the highest priority. Therefore, the output unit 2 outputs traffic from the BE class queue to the transmission queue after the traffic from the EF class, AF4 class, and AF1 class with the highest priority has been output. Traffic becomes burst traffic due to aggregation, delay, fluctuation, etc. Burst traffic refers to a group of frames generated by delay, fluctuation, etc. When multiple burst traffic streams overlap, the input rate becomes higher than the output rate, and the burst traffic is buffered.

[0004] As a result, frames that cannot be stored in the buffer (buffer overflow) are discarded, resulting in frame loss. For priority class traffic (especially traffic that does not require retransmission, such as UDP (User Datagram Protocol)), frame loss affects service quality. For this reason, it is important to design priority class buffers based on the expected traffic volume and burst volume to prevent frame loss.

[0005] Figure 7 shows the relationship between burstiness and frame discard. The upper diagram in Figure 7 shows traffic with low burstiness, while the lower diagram in Figure 7 shows traffic with high burstiness. Traffic with low burstiness is buffered and immediately retrieved as shown in Figure 7, so no frame discard occurs. On the other hand, traffic with high burstiness will partially discard frames when it exceeds the buffer capacity, as shown in Figure 7.

[0006] Conventionally, methods for calculating buffer capacity have been proposed, including a method using a statistical method and a method using an accumulation method. The method for calculating buffer capacity using a statistical method uses the M / D / 1 queuing model. In the M / D / 1 model, "M" represents the arrival interval, "D" represents the processing time, and "1" represents the number of queues. Figure 8 shows the relationship between the ratio of input traffic to output link speed (utilization rate) and the number of burst traffics requiring buffering in the M / D / 1 model.

[0007] FIG. 8A is a diagram showing the relationship between the ratio (utilization rate) of input traffic to the output link speed in the M / D / 1 model and the number of burst traffics that require a buffer, and FIG. 8B is an enlarged view of a portion of FIG. 8A. The number of burst traffics that require a buffer varies depending on the discard rate. The smaller the discard rate, the less frame loss there is, and therefore the larger the required buffer. For example, if the input traffic is 2 Gbps and the output link speed is 10 Gbps, the utilization rate is 0.2 (= 2 Gbps / 10 Gbps). Therefore, if the discard rate calculated from the M / D / 1 model is 10 －５ The number of bursts that require buffering below is 5. If the burst size of the input traffic is 10 KB, then the required buffer capacity is 50 KB (10 KB x 5).

[0008] Next, a method for calculating the buffer capacity using the accumulation method will be described. In the method for calculating the buffer capacity using the accumulation method, the expected burst traffic size (burst size) is calculated based on the required bandwidth of stream j (j is an integer equal to or greater than 1) of service i. ｉ,ｊAssuming the worst case scenario, the buffer size is calculated based on the following formula (1) so that no frame loss occurs even when all services i and all streams j arrive at the frame buffer at the same time.

[0009] ΣB ｉ,ｊ [byte] (i=1,2,...,n,j=1,2,...,m)...Formula (1)

[0010] For example, if the expected traffic of a communication device is streams 1 to 3 as shown in FIG. 9, and the expected burst sizes of streams 1 to 3 are 10 KB, 20 KB, and 30 KB, respectively, then the required buffer size will be a total of 60 KB.

[0011] JP 2012-049746 A JP 2012-105086 A

[0012] The buffer capacity of a communication device is limited, and the smaller the buffer capacity, the less power the communication device consumes. However, in the past, the buffer capacity was calculated using a predetermined calculation method regardless of the traffic type, resulting in a buffer capacity that was greater than necessary. As such, there is room for improvement in reducing the power consumption of communication devices.

[0013] In view of the above circumstances, an object of the present invention is to provide a technique that can reduce the power consumption of a communication device.

[0014] One aspect of the present invention is a calculation device that calculates a buffer amount for each queue in a communication device that performs priority control using multiple queues, the calculation device comprising: a first buffer calculation unit that calculates the buffer amount for each queue using a first buffer calculation method based on the number of users using a service and service usage information of the users; a second buffer calculation unit that calculates the buffer amount for each queue using a second buffer calculation method that is a calculation method different from the first buffer calculation method based on the number of users using the service and the service usage information of the users; and a buffer amount determination unit that determines the buffer amount to be set in the buffer of each queue included in the communication device based on the buffer amount for each queue calculated by the first buffer calculation unit and the buffer amount for each queue calculated by the second buffer calculation unit.

[0015] According to the present invention, it is possible to reduce the power consumption of a communication device.

[0016] FIG. 1 is a diagram illustrating an example of the configuration of a communication system in a first embodiment. FIG. 2 is a diagram illustrating an example of a user registration DB, a service type information table, and a service information table stored in a storage unit in the first embodiment. FIG. 3 is a flowchart illustrating the flow of a buffer amount calculation process performed by an access device in the first embodiment. FIG. 4 is a diagram illustrating an example of the configuration of a communication system in a second embodiment. FIG. 5 is a diagram illustrating an example of the configuration of a communication system in a third embodiment. FIG. 6 is a diagram illustrating the flow of priority control in a communication device. FIG. 7 is a diagram illustrating the relationship between burstiness and frame discarding. FIG. 8 is an explanatory diagram of an M / D / 1 model. FIG. 9 is an explanatory diagram of a stacking method.

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] (Summary) Before describing the specific contents of the present invention, an overview of the present invention will be first described. A communication device according to the present invention performs priority control using a buffer having multiple queues, as in the past. What makes the present invention different from the past is that it selectively uses a buffer amount calculated using a buffer amount calculation method that uses a statistical method and a buffer amount calculated using a buffer amount calculation method that uses an accumulation method depending on the traffic type. This makes it possible to set a buffer amount calculated using an appropriate calculation method depending on the traffic type. As a result, it becomes possible to design a buffer with the minimum necessary buffer amount set, thereby reducing the power consumption of the communication device. Below, a specific configuration for realizing the above processing will be described.

[0019] 1 is a diagram showing an example of the configuration of a communication system 100 according to a first embodiment. The communication system 100 includes a lower device 10, an access device 20, and a higher device 30. The lower device 10 and the higher device 30 are connected via the access device 20.

[0020] The lower device 10 communicates with the upper device 30. For example, the lower device 10 transmits an upstream signal addressed to the upper device 30 having a different priority.

[0021] The access device 20 is a communication device that uses multiple queues to perform priority control between the lower device 10 and the upper device 30. The access device 20 has a function of calculating a buffer amount for each queue. The access device 20 is one aspect of a calculation device.

[0022] The upper device 30 communicates with the lower device 10. For example, the upper device 30 receives an uplink signal transferred from the access device 20.

[0023] (Device Configuration) Next, a description will be given of the configuration of the access device 20. The access device 20 includes a storage unit 21, a buffer capacity determination unit 22, a first buffer calculation unit 23, a second buffer calculation unit 24, a buffer setting unit 25, and a transfer processing unit 26.

[0024] The storage unit 21 stores various types of information. Specifically, the storage unit 21 stores a user registration DB, a service type information table, and a service information table. The user registration DB is a database in which information about users who use services is registered. The service type information table is a table in which information about service types is registered. The service information table is a table in which information about services is registered. Details of the information stored in the storage unit 21 will be described later.

[0025] The first buffer calculation unit 23 calculates the buffer amount for each queue using a first buffer calculation method based on various information stored in the storage unit 21. Specifically, the first buffer calculation unit 23 calculates the buffer amount for each queue using an existing statistical method. The buffer amount for each queue calculated by the first buffer calculation unit 23 is the buffer amount for each queue that is estimated to be required depending on the current traffic situation.

[0026] The second buffer calculation unit 24 calculates the buffer amount using a second buffer calculation method based on various information stored in the storage unit 21. Specifically, the second buffer calculation unit 24 calculates the buffer amount for each queue using an existing accumulation method. The buffer amount for each queue calculated by the second buffer calculation unit 24 is the buffer amount for each queue that is estimated to be required depending on the current traffic situation.

[0027] The buffer amount determination unit 22 determines the buffer amount to be set in the queue corresponding to each class included in the forwarding processing unit 26 based on the buffer amount for each queue calculated by the first buffer calculation unit 23 (hereinafter referred to as the "first buffer amount") and the buffer amount for each queue calculated by the second buffer calculation unit 24 (hereinafter referred to as the "second buffer amount"). Specifically, the buffer amount determination unit 22 compares the first buffer amount with the second buffer amount and determines the smaller buffer amount for each queue (each class) as the buffer amount for each queue. In this way, the buffer amount determination unit 22 determines the optimal buffer amount (the minimum necessary buffer amount) for each queue.

[0028] The buffer setting unit 25 sets the buffer capacity for each queue determined by the buffer capacity determining unit 22 in the buffer of each queue provided in the transfer processing unit 26 .

[0029] The transfer processing unit 26 transfers signals between the lower-level device 10 and the upper-level device 30. The transfer processing unit 26 has a plurality of queues for buffering traffic with different priorities. The transfer processing unit 26 performs transfer processing based on the buffer amount set for each queue by the buffer setting unit 25.

[0030] (Database) Fig. 2 is a diagram showing an example of a user registration DB, a service type information table, and a service information table stored in the storage unit 21 in the first embodiment. Fig. 2(A) shows an example of the user registration DB, Fig. 2(B) shows an example of the service type information table, and Fig. 2(C) shows the service information table.

[0031] The user registration DB has multiple records that represent information about users who use a service. Each record has values ​​for a user ID, a VLAN, and a service type. The user ID represents identification information for identifying a user who uses a service. The VLAN represents identification information (VLAN ID) for a VLAN (Virtual Local Area Network) that is set for traffic sent by a user who uses a service. The service type represents the type of service being used by a user who uses a service.

[0032] The service type information table has multiple records that represent information about service types. Each record has values ​​for service type, service A, service B, and service C. The service type represents the type of service. Service A, service B, and service C represent details of the service. As shown in FIG. 2, available services are shown for each service type. For example, "Available" in FIG. 2B indicates that the service is available, and "Not Available" in FIG. 2B indicates that the service is not available. Therefore, service type "1" indicates that service A is available, and services B and C are not available.

[0033] The service information table has multiple records that represent information about services. Each record has values ​​for service, bandwidth, number of streams, and expected burst size. The service represents details of the service. The bandwidth represents the bandwidth available for the service. The number of streams represents the number of streams available for the service. The expected burst size represents the size of burst traffic.

[0034] (Operation) FIG. 3 is a flowchart showing the flow of the buffer capacity calculation process performed by the access device 20 in the first embodiment. The first buffer calculation unit 23 calculates the buffer capacity for each queue using a statistical method based on information stored in the storage unit 21 (step S101). For example, the first buffer calculation unit 23 classifies each user based on their VLAN ID, based on the user registration DB 27 stored in the storage unit 21. Next, the first buffer calculation unit 23 refers to the service type information table to identify the service type for each class. Then, the first buffer calculation unit 23 refers to the service information table to acquire information on each service included in the identified service type for each class (bandwidth, number of streams, expected burst size). The first buffer calculation unit 23 calculates the buffer capacity for each queue using a statistical method based on the acquired information on each service included in the service type for each class and the number of users for each class. The first buffer calculation unit 23 outputs the calculation result to the buffer capacity determination unit 22.

[0035] The second buffer calculation unit 24 calculates the buffer capacity for each queue using an accumulation method based on the information stored in the storage unit 21 (step S102). For example, the second buffer calculation unit 24 classifies each user based on their VLAN ID, based on the user registration DB 27 stored in the storage unit 21. Next, the second buffer calculation unit 24 refers to the service type information table to identify the service type for each class. Then, the second buffer calculation unit 24 refers to the service information table to acquire information (bandwidth, number of streams, expected burst size) of each service included in the identified service type for each class. The second buffer calculation unit 24 may calculate the buffer capacity for each queue using an accumulation method based on the acquired information of each service included in the service type for each class and the number of users for each class. The second buffer calculation unit 24 outputs the calculation result to the buffer capacity determination unit 22.

[0036] The buffer amount determination unit 22 determines the buffer amount to be set for each queue corresponding to each class included in the transfer processing unit 26 based on the first buffer amount for each queue output from the first buffer calculation unit 23 and the second buffer amount for each queue output from the second buffer calculation unit 24 (step S103). At this time, the buffer amount determination unit 22 selects the smaller buffer amount for each queue. Therefore, either the first buffer amount or the second buffer amount is selected for each queue. Note that when the buffer amounts are the same, the buffer amount calculated by either method may be used. The buffer amount determination unit 22 outputs information indicating the determined buffer amount for each queue to the buffer setting unit 25. The buffer setting unit 25 sets the buffer amount for each queue to the transfer processing unit 26 based on the information indicating the buffer amount for each queue output from the buffer amount determination unit 22 (step S104).

[0037] According to the communication system 100 configured as described above, the access device 20 includes a first buffer calculation unit 23 that calculates the buffer amount for each queue using a first buffer calculation method based on the number of users using the service and the users' service usage information; a second buffer calculation unit 24 that calculates the buffer amount for each queue using a second buffer calculation method, which is a calculation method different from the first buffer calculation method, based on the number of users using the service and the users' service usage information; and a buffer amount determination unit 22 that determines the buffer amount to be set in the buffer of each queue included in the access device 20 based on the buffer amount for each queue calculated by the first buffer calculation unit 23 and the buffer amount for each queue calculated by the second buffer calculation unit 24.

[0038] In this way, the access device 20 calculates the buffer amount for each queue using different methods and determines the buffer amount to be set in the buffer for each queue (queue corresponding to each class), so it is possible to set a more appropriate buffer amount for each queue. This makes it possible to design a buffer with the minimum necessary buffer amount set. As a result, it is possible to reduce the power consumption of the access device 20.

[0039] The above-mentioned effects will be explained in more detail. In a buffer size calculation method using a statistical method, the size of a single burst of input traffic is considered under the worst-case scenario. Therefore, for example, if the size of a single burst is defined as 100 KB, even if the number of accommodated users is small and the input traffic is low, the number of bursts required for the buffer will be one based on the M / D / 1 model, and a buffer size of 100 KB will be required. On the other hand, in a buffer size calculation method using an accumulation method, when the number of accommodated users is small and the input traffic is low, the buffer size may be smaller than that obtained by a buffer size calculation method using a statistical method when the sum of the burst sizes of each stream is calculated. For example, if the traffic consists of streams 1 to 3 and the expected burst sizes of each stream are 10 KB, 20 KB, and 30 KB, respectively, the sum of 60 KB will be the buffer size. In this way, the buffer size may be smaller than that obtained by a buffer size calculation method using a statistical method. Note that, when the number of users is large, the buffer size may be larger in a buffer size calculation method using an accumulation method than in a buffer size calculation method using a statistical method. In this way, the appropriate buffer amount varies depending on the number of users, between the method of calculating the buffer amount using the accumulation method and the method of calculating the buffer amount using the statistical method. Therefore, when the number of accommodated users is less than a threshold, the access device 20 calculates the buffer amount for each queue using the accumulation method, and when the number of accommodated users is equal to or greater than the threshold, it calculates the buffer amount for each queue using the statistical method. This makes it possible to avoid calculating an unnecessarily large buffer amount, as described above. This makes it possible to design a buffer that sets the minimum necessary buffer amount. As a result, it becomes possible to reduce the power consumption of the access device 20.

[0040] When the number of users accommodated is small (when the number of accommodated users is less than a threshold), the total buffer capacity of the priority class can be small even if the buffer capacity is calculated using the accumulation method. In the case of multiple class queues, priority is given to the traffic quality of the priority class, so after the buffer for the priority class queue is designed, the remaining finite buffer is allocated to the best-effort queue. Setting a smaller buffer using the buffer calculation method for each priority class queue allows more queues corresponding to best-effort traffic to be secured. In this way, buffers for best-effort traffic can be allocated, and frame loss during congestion of best-effort traffic can be reduced. This allows for improved throughput (improved service quality).

[0041] Second Embodiment In the first embodiment, a configuration was shown in which a function for determining a buffer size to be set, a function for calculating the buffer size, and a function for performing transfer were integrated into one device. In the second embodiment, a configuration will be described in which a function for determining a buffer size to be set and a function for calculating the buffer size are provided in an EMS (Element Management System) that manages the system, and a function for performing transfer is provided in an access device.

[0042] 4 is a diagram showing an example of the configuration of a communication system 100a in the second embodiment. The communication system 100a includes a lower-level device 10, an access device 20a, a higher-level device 30, and an EMS 40a. The lower-level device 10 and the higher-level device 30 are connected via the access device 20a. The configuration of the communication system 100a differs from that of the communication system 100 in that the communication system 100a includes the access device 20a instead of the access device 20 and that the communication system 100a newly includes an EMS 40a. The following description will focus on the differences from the communication system 100.

[0043] The EMS 40a is a device that manages the entire communication system 100a. For example, the EMS 40a configures (including changing) and monitors the access device 20a. An operator of the access device 20a intuitively configures and monitors the status of the access device 20a using the GUI (Graphical User Interface) of the EMS 40a, rather than directly configuring and monitoring the status of the access device 20a using a CLI (Command Line Interface). The EMS 40a has a function of calculating the buffer amount for each queue in the buffer provided in the access device 20a. The EMS 40a is one aspect of a calculation device.

[0044] The access device 20a uses a plurality of queues to perform priority control between the lower device 10 and the upper device 30. In the access device 20a, the buffer amount for each queue is set by the EMS 40a.

[0045] (Device Configuration) Next, the configurations of the access device 20a and the EMS 40a will be described. The EMS 40a includes a storage unit 21, a buffer capacity determination unit 22, a first buffer calculation unit 23, a second buffer calculation unit 24, and a buffer setting unit 25. Each functional unit included in the EMS 40a performs the same processing as the functional unit with the same name described in the first embodiment.

[0046] The access device 20 includes a transfer processing unit 26 and a user registration DB 27. The transfer processing unit 26 transfers signals between the lower device 10 and the upper device 30. The transfer processing unit 26 performs transfer processing based on the buffer amount set for each queue by the EMS 40a.

[0047] The user registration DB 27 is a database similar to the database shown in FIG.

[0048] (Operation) Next, the operation of the communication system 100a in the first embodiment will be described. The first buffer calculation unit 23 included in the EMS 40a calculates the buffer amount for each queue using a statistical method based on the information stored in the storage unit 21. The first buffer calculation unit 23 outputs the calculation result to the buffer amount determination unit 22. The second buffer calculation unit 24 included in the EMS 40a calculates the buffer amount for each queue using an accumulation method based on the information stored in the storage unit 21. The second buffer calculation unit 24 outputs the calculation result to the buffer amount determination unit 22.

[0049] The buffer amount determination unit 22 determines the buffer amount to be set in the queue corresponding to each class included in the forwarding processing unit 26 of the access device 20a, based on the first buffer amount for each queue output from the first buffer calculation unit 23 and the second buffer amount for each queue output from the second buffer calculation unit 24. At this time, the buffer amount determination unit 22 selects the smaller buffer amount for each queue. Therefore, either the first buffer amount or the second buffer amount is selected for each queue. Note that when the buffer amounts are the same, the buffer amount calculated by either method may be used. The buffer amount determination unit 22 outputs information indicating the determined buffer amount for each queue to the buffer setting unit 25. The buffer setting unit 25 sets the buffer amount for each queue for the forwarding processing unit 26 of the access device 20a, based on the information indicating the buffer amount for each queue output from the buffer amount determination unit 22.

[0050] According to the communication system 100a configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0051] Furthermore, in the communication system 100a, the access device 20a does not need a buffer calculation function. Therefore, a low-cost central processing unit (CPU) with a slow processing speed can be selected for the access device 20a, and the memory (ROM: Read Only Memory) for recording the expected burst size for each user can be made smaller. This allows the cost of the access device 20a to be reduced.

[0052] Third Embodiment In the third embodiment, a configuration will be described in which a device different from those in the first and second embodiments determines the buffer amount to be set. Specifically, in the third embodiment, a configuration will be described in which a buffer calculation device that determines the buffer amount to be set is further provided in an EMS (Element Management System) that manages the system, and a function for performing transfer is provided in an access device.

[0053] In the third embodiment, the ultimate demand of the access device (the number of users to be accommodated at the end) is determined, and the buffer amount calculated in advance using a statistical method based on the expected final number of users and service information is compared with the buffer amount calculated using an accumulation method, and a smaller buffer amount is set for each priority class.

[0054] For example, when a communications building with access equipment installed provides access services to a new station or a new area, the number of households in that area and the capacity of access equipment for the ultimate demand in similar areas are used to predict the number of households multiplied by the capacity. Service information is also predicted by grasping the service subscription rate in similar areas.

[0055] 5 is a diagram showing an example of the configuration of a communication system 100b according to the third embodiment. The communication system 100b includes a lower-level device 10, an access device 20a, a higher-level device 30, an EMS 40b, and a buffer calculation device 50b. The lower-level device 10 and the higher-level device 30 are connected via the access device 20a. The configuration of the communication system 100b differs from that of the communication system 100a in that the communication system 100b includes an EMS 40b instead of the EMS 40a and that the communication system 100b newly includes a buffer calculation device 50b. The following description will focus on the differences from the communication system 100a.

[0056] The buffer calculation device 50b has a function of calculating the buffer amount for each queue in the buffer provided in the access device 20a. The buffer calculation device 50b is one aspect of a calculation device.

[0057] The EMS 40b is a device that manages the entire communication system 100b, and has a function of setting the buffer amount for each queue calculated by the buffer calculation device 50b in the access device 20a.

[0058] (Device Configuration) Next, the configurations of the EMS 40b and the buffer calculation device 50b will be described. The EMS 40b includes a buffer setting unit 25. The buffer setting unit 25 included in the EMS 40b performs the same processing as the functional unit of the same name described in the second embodiment.

[0059] The buffer calculation device 50b includes a storage unit 21, a buffer amount determination unit 22, a first buffer calculation unit 23, and a second buffer calculation unit 24. The buffer amount determination unit 22, the first buffer calculation unit 23, and the second buffer calculation unit 24 included in the buffer calculation device 50b perform the same processing as the functional units with the same names described in the second embodiment.

[0060] (Operation) Next, the operation of the communication system 100b in the third embodiment will be described. The first buffer calculation unit 23 included in the buffer calculation device 50b refers to the information stored in the storage unit 21 and calculates the buffer amount for each queue (each class) using a statistical method. The first buffer calculation unit 23 outputs the calculation result to the buffer amount determination unit 22. The second buffer calculation unit 24 included in the buffer calculation device 50b refers to the information stored in the storage unit 21 and calculates the buffer amount for each queue using an accumulation method. The second buffer calculation unit 24 outputs the calculation result to the buffer amount determination unit 22.

[0061] The buffer amount determination unit 22 determines a buffer amount to be set in a queue corresponding to each class provided in the transfer processing unit 26 of the access device 20 a, based on the first buffer amount for each queue output from the first buffer calculation unit 23 and the second buffer amount for each queue output from the second buffer calculation unit 24. The buffer amount determination unit 22 outputs information indicating the determined buffer amount for each queue to the buffer setting unit 25 provided in the EMS 40 b. The buffer setting unit 25 provided in the EMS 40 b sets the buffer amount for each queue for the transfer processing unit 26 of the access device 20 a, based on the information indicating the buffer amount for each queue output from the buffer amount determination unit 22.

[0062] The communication system 100b configured as described above can achieve the following effects. In the first and second embodiments, in which buffers are changed as needed, the priority class buffer is increased each time the number of users increases, so there is no impact on priority class services. However, because buffers are finite, if the best effort buffer is reduced by the amount of the priority class buffer increased, best effort frame loss may occur, which may impact best effort services. In contrast, the communication system 100b sets buffers in advance based on ultimate demand, so the above problem can be avoided.

[0063] Some or all of the functional units of the access devices 20, 20a, EMSs 40a, 40b, and buffer calculation device 50b are realized as software by a processor such as a CPU executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and a storage unit. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs (Compact Disc Read Only Memory), and storage devices such as hard disks built into a computer system.

[0064] Some or all of the functional units of the access devices 20, 20a, EMSs 40a, 40b, and buffer calculation device 50b may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0065] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0066] The present invention can be applied to a technique for performing priority control using multiple queues.

[0067] REFERENCE SIGNS LIST 10... lower-level device, 20, 20a... access device, 30... upper-level device, 40a, 40b... EMS, 50b... buffer calculation device, 21... storage unit, 22... buffer capacity determination unit, 23... first buffer calculation unit, 24... second buffer calculation unit, 25... buffer setting unit, 26... transfer processing unit, 27... user registration DB, 100, 100a, 100b... communication system

Claims

1. A calculation device that calculates a buffer amount for each queue in a communication device that performs priority control using multiple queues, comprising: a first buffer calculation unit that calculates a buffer amount for each queue using a first buffer calculation method based on the number of users using a service and service usage information of the users; a second buffer calculation unit that calculates a buffer amount for each queue using a second buffer calculation method that is a calculation method different from the first buffer calculation method based on the number of users using the service and service usage information of the users; and a buffer amount determination unit that determines a buffer amount to set in the buffer of each queue provided in the communication device based on the buffer amount for each queue calculated by the first buffer calculation unit and the buffer amount for each queue calculated by the second buffer calculation unit.

2. The calculation device according to claim 1, wherein the buffer amount determination unit compares the buffer amounts for each queue calculated by the first buffer calculation unit and the second buffer calculation unit, and selects the lower buffer amount for each queue.

3. The calculation device according to claim 1 or 2, wherein the first buffer calculation unit calculates the buffer amount for each queue using a buffer amount calculation method that uses a statistical method as the first buffer calculation method, and the second buffer calculation unit calculates the buffer amount for each queue using a buffer amount calculation method that uses an accumulation method as the second buffer calculation method.

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