JP5458957B2 - Communication apparatus, traffic amount control method, and program - Google Patents

Description

  Embodiments discussed herein relate to a traffic volume control technique in data communication performed by exchanging communication packets.

  In a relay device that relays data communication between communication networks, a token bucket method is known as one of techniques for controlling the traffic volume when transmitting received communication traffic. The principle of this token bucket method will be described with reference to FIG.

  In FIG. 18, the bucket 100 is replenished with tokens 101 at regular time intervals. In this bucket 100, the maximum storage amount (maximum amount that can store the token 101) is predetermined, and the token 101 exceeding the maximum storage amount is discarded.

  The token 101 has a predetermined data transmission amount. When the relay device transmits a communication data packet (hereinafter simply referred to as “packet 111”) received from the upstream device to the downstream device, the packet control point 110 uses the token 101 stored in the bucket 100 as a packet. A number n corresponding to the size of 111 is consumed. However, when the number of tokens 101 corresponding to the size of the packet 111 to be transmitted is insufficient in the bucket 100, the packet 111 is discarded without being targeted for transmission (policing).

  As described above, in this token bucket method, the packet 111 to be transmitted that has passed without being discarded at the packet control point 110 because the necessary number of tokens 101 are stored is in a transmission waiting state. For this reason, if transmission of the transmission target packet 111 is delayed due to other factors such as an increase in traffic, the transmission target packet 111 stays in a large amount in the relay apparatus. Further, when the traffic situation is recovered thereafter, a large amount of packets 111 are transmitted in order to discharge the staying transmission target packets 111 at once. Then, in the downstream communication network, the packet 111 transmitted in large quantities may cause congestion for a while.

  Several techniques are known regarding techniques for suppressing downstream congestion when this token bucket method is employed. The first of these is the updated value of the token output frequency to the token buffer based on the communication data throughput in the token buffer where tokens are held (decreasing state). It is to decide. In this technique, the token output frequency to the token buffer when the token in the token buffer continues to decrease and eventually becomes empty (depleted state) is set to the determined value. Furthermore, in this technique, when this depletion state continues for a predetermined time, a predetermined amount of tokens are added to the token buffer at a stretch, and the token buffer is shifted to a decrease state.

  In addition, the second of these technologies uses a communication speed that can be set for a link used for connection to a network, and link congestion information that indicates a degree of congestion of the link connected to the network, to the token buffer. The token output frequency is updated.

JP 2007-221529 A JP 2008-5096 A

  In the first technique described above, when the communication data throughput decreases due to factors such as an increase in other traffic, it is necessary to reduce the frequency of token output to the token buffer in order to avoid excessive retention of communication data. There seems to be. As a result, the token buffer is reduced and further transitions to a depleted state. After that, a predetermined amount of tokens are added to the token buffer after a predetermined time after the token buffer transitions to a depletion state, and an operation of transitioning to a decrease state is performed. However, if tokens are added to the token buffer in this way, eventually, congestion will occur for a while in the downstream communication network. Here, if the amount of tokens added to the token buffer is set to zero, the token buffer will not be able to escape from the depleted state even if the above-mentioned factors are eliminated, so the communication data throughput will be restored to the original state. It is thought that will be impossible.

  The present invention has been made in view of the above-described problems, and the problem to be solved is to reduce congestion of communication packets and reduce congestion in a downstream communication network due to elimination of retention of communication data packets. It is to reduce.

One of the communication devices described later in this specification includes a token amount management table, a reception unit, a token amount decrease unit, a transmission unit, a token amount increase unit, and a token amount update unit. . Among these, the token amount management table is a table that manages the number of tokens held in each of the first bucket and the second bucket that hold the tokens for which the total number is predetermined. The receiving means is for receiving a communication data packet. The token amount reducing means decreases the number of tokens held in the first bucket in the token quantity management table by the number corresponding to the size of the communication data packet received by the receiving means. The transmitting means transmits the communication data packet received by the receiving means. The token amount increasing means increases the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmitting means. The token amount update means updates the token amount management table. This update decreases the number of tokens held in the second bucket in the token amount management table by a predetermined number at a predetermined frequency and reduces the number of tokens held in the first bucket in the token amount management table. The amount is increased by the decrease. However, there are cases where the number of tokens held in the first bucket in the token amount management table is less than the number corresponding to the size of the communication data packet received by the receiving means. In this case, the amount of token reducing means is configured to maintain the retention number of tokens in said first bucket in the token management table, the communication data packet to discard without transmitting to said transmission means To do.

  In addition, as one of the traffic volume control methods described later in this specification, there is a method of performing using a communication apparatus having a reception unit that receives a communication data packet and a transmission unit that transmits the communication data packet. This control method includes a token amount decrease step, a token amount increase step, and a token amount update step. Among these, the token amount reduction step is to reduce the number of tokens held in the first bucket in the token amount management table to be managed by the number corresponding to the size of the communication data packet received by the receiving means. . The token amount management table is a table that manages the number of tokens held in each of the first bucket and the second bucket that hold the tokens for tokens whose total number is predetermined. In the token amount increasing step, the number of tokens held in the second bucket in the token amount management table is increased by the number corresponding to the size of the communication data packet transmitted by the transmitting unit. In the token amount update step, the token amount management table is updated. This update decreases the number of tokens held in the second bucket in the token amount management table by a predetermined number at a predetermined frequency and sets the number of tokens held in the first bucket in the token amount management table to It is to increase by the decrease. However, there are cases where the number of tokens held in the first bucket in the token amount management table is less than the number corresponding to the size of the communication data packet received by the receiving means. In this case, in the token amount reduction step, the number of tokens held in the first bucket in the token amount management table is maintained, and the communication data packet is discarded without being transmitted to the transmission means. To do.

In addition, one of the programs described later in this specification includes an arithmetic processing unit that controls the amount of traffic performed using a communication apparatus having a reception unit that receives a communication data packet and a transmission unit that transmits the communication data packet. There is something to do. This program causes the arithmetic processing unit to perform token amount decrease processing, token amount increase processing, and token amount update processing. Among these, the token amount reduction process is to reduce the number of tokens held in the first bucket in the token amount management table by the number corresponding to the size of the communication data packet received by the receiving means. The token amount management table is a table that manages the number of tokens held in each of the first bucket and the second bucket that hold the tokens for tokens whose total number is predetermined. The token amount increasing process is to increase the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmitting unit. Then, the token amount update process updates the token amount management table. This update decreases the number of tokens held in the second bucket in the token amount management table by a predetermined number at a predetermined frequency and sets the number of tokens held in the first bucket in the token amount management table to It is to increase by the decrease. However, there are cases where the number of tokens held in the first bucket in the token amount management table is less than the number corresponding to the size of the communication data packet received by the receiving means. In this case, in the amount of token down increase process, while maintaining the holding number of tokens in said first bucket in the token management table, so that the communication data packet discards without sent to the transmission means To.

  Also, one of the communication devices described later in this specification includes a predetermined number of tokens, a first bucket and a second bucket, a receiving unit, a token granting unit, a transmitting unit, and a first token storage. And a second token storage means. Among these, the first bucket and the second bucket hold the token. The receiving means receives a communication data packet. The token giving means takes out a number of tokens corresponding to the size of the communication data packet received by the receiving means from the first bucket and gives the token to the communication data packet. The transmission means transmits the communication data packet to which the token is given by the token grant means. The first token storage means stores and holds the token attached to the communication data packet transmitted by the transmission means in the second bucket. The second token storage means takes out the token held in the second bucket at a predetermined frequency, stores it in the first bucket, and holds it. However, the number of tokens held in the first bucket may not be enough according to the size of the communication data packet received by the receiving means. In this case, the token granting unit discards the communication data packet.

  The communication device described later in this specification reduces the congestion of communication packets in the downstream communication network due to the reduction of communication packet retention and the elimination of communication data packet retention.

It is an example of a structure of a packet communication network. It is a functional block diagram illustrating the function which a host system has. It is a functional block diagram illustrating the function which a router has. It is an example of a standard hardware configuration of a computer. It is a figure explaining control of the traffic amount performed by a router. It is an example of a data structure of a token amount management table. It is an example of the data structure of the packet to which the token is given. It is an example of a data structure of a token grant management table. It is the flowchart which illustrated the processing content of the 1st example of a token provision process. It is the flowchart which illustrated the processing content of the 1st example of a token release process. It is an example of the time change of the packet reception amount and the packet transmittable amount. This is a state (Part 1) of packet retention and transmission when the traffic volume is controlled using the conventional technology. This is a state (part 2) of packet retention and transmission when the traffic volume is controlled using the conventional technology. This is a state (part 3) of packet retention and transmission when the traffic volume is controlled using the conventional technology. FIG. 4 shows packet retention and transmission when the traffic volume is controlled by the router having the configuration of FIG. It is the flowchart which illustrated the processing content of the 2nd example of a token release process. It is the flowchart which illustrated the processing content of the 2nd example of a token provision process. It is the flowchart which illustrated the processing content of the 3rd example of a token provision process. It is the flowchart which illustrated the processing content of the token pumping-up process. It is a figure explaining the principle of a token bucket system.

  First, FIG. 1 will be described. FIG. 1 illustrates an example of the configuration of a packet data communication network. This communication network includes four host systems 1, 2, 3, and 4 that are communication terminals, and two routers (relay devices) 5 and 6 that are communication devices. Here, the host system 1 (Host # A) and the host system 2 (Host # B) are directly connected to the router 5 (#A), and the host system 3 (Host # B) and the host system 4 (Host # D) is directly connected to the router 6 (#B). Further, the router 5 and the router 6 are connected. Therefore, when the host system 1 or 2 communicates with the host system 3 or 4, it is necessary to go through both the routers 5 and 6.

  In the following description, in the communication network of FIG. 1, the flow rate (traffic amount) of communication data packets (hereinafter simply referred to as “packets”) transmitted from the host system 1 and received by the host system 3 Suppose that is controlled.

  Next, FIG. 2 will be described. FIG. 2 is a functional block diagram illustrating the functions of the host system 1 of FIG. Each of the other host systems 2, 3 and 4 in FIG. 1 may have the same function as the host system 1.

As can be seen from FIG. 2, the host system 1 includes a control unit 11, a storage unit 12, an input / output control unit 13, and a communication control unit 14 as functional blocks.
The control unit 11 has a function of controlling the operation of the entire host system 1.

The storage unit 12 has a function of storing and holding various data under management by the control unit 11.
The input / output control unit 13 has a function of controlling the operation of an input device such as a keyboard device or mouse device and an output device such as a display device under management by the control unit 11. When an operation on the input device by a user or the like of the host system 1 is detected, the input / output control unit 13 acquires input of various information associated with the operation content, and the acquired input information is transmitted to the control unit. 11 to send. When the input / output control unit 13 receives the output data from the control unit 11, the input / output control unit 13 controls the output device and outputs various texts and images expressed by the output data.

  The communication control unit 14 controls a communication device that transmits and receives packets under the management of the control unit 11, and exchanges packets with the router 5 that is physically connected to the host system 1. It has a function.

  Next, FIG. 3 will be described. FIG. 3 is a functional block diagram illustrating the functions of the router 5 of FIG. Note that the router 6 in FIG. 1 may have the same function as the router 5.

As can be seen from FIG. 3, the router 5 includes a control unit 21, a storage unit 22, an input / output control unit 23, a communication control unit 24, and a clock control unit 25 as functional blocks.
The control unit 21 has a function of controlling the operation of the entire router 5.

  The storage unit 22 has a function of storing and holding various data under management by the control unit 21. FIG. 3 illustrates that the storage unit 22 particularly includes a storage area for storing the token amount management table 22-1, the token granting table 22-2, and the packet buffer 22-3. However, these details will be described later.

  The input / output control unit 23 has a function of controlling the operation of an input device such as a keyboard device or a mouse device and an output device such as a display device under management by the control unit 21. When an operation on the input device by the administrator of the communication network in FIG. 1 is detected, the input / output control unit 23 acquires input of various information associated with the operation content, and the acquired input information is displayed. It is sent to the control unit 21. When the input / output control unit 23 receives the output data from the control unit 21, the input / output control unit 23 controls the output device to output various texts and images expressed by the output data.

  The communication control unit 24 controls an interface device that transmits and receives packets under the management of the control unit 21, and communicates with the host system 1 or 2 or the router 6 that is physically connected to the host system 1. It has a function to exchange packets between them.

The clock control unit 25 has a clock function for measuring the current date and time.
Note that a computer having a standard hardware configuration as illustrated in FIG. 4 can also function as the router 5 or 6. Next, FIG. 4 will be described.

  The computer 30 includes an MPU 31, ROM 32, RAM 33, hard disk device 34, input device 35, display device 36, interface device 37, and recording medium drive device 38. These components are connected via a bus 39, and various data can be exchanged under the management of the MPU 31.

An MPU (Micro Processing Unit) 31 is an arithmetic processing unit that controls the operation of the entire computer 30.
A ROM (Read Only Memory) 32 is a read-only semiconductor memory in which a predetermined basic control program is recorded in advance. The MPU 31 reads out and executes this basic control program when the computer 30 is activated, thereby enabling operation control of each component of the computer 30.

  A RAM (Random Access Memory) 33 is a semiconductor memory that can be written and read at any time and used as a working storage area as necessary when the MPU 31 executes various control programs.

  The hard disk device 34 is a storage device that stores various control programs executed by the MPU 31 and various data. The MPU 31 can perform various control processes described later by reading and executing a predetermined control program stored in the hard disk device 34.

  The input device 35 is, for example, a keyboard device or a mouse device. When operated by a user of the computer 30, the input device 35 acquires input of various information from the user associated with the operation content, and acquires the acquired input information. Is sent to the MPU 31.

The display device 36 is a liquid crystal display, for example, and displays various texts and images according to display data sent from the MPU 31.
The interface device 37 exchanges various data with various devices connected to the computer 30. Accordingly, the interface device 37 functions as a receiving device that receives a packet sent from the host system 1 and transmits the packet to the host system 3 that is the destination of the packet after a predetermined process. It also functions as a device.

  The recording medium driving device 38 is a device that reads various control programs and data recorded on the portable recording medium 40. The MPU 31 can read out and execute a predetermined control program recorded in the portable recording medium 40 via the recording medium driving device 38 to perform various control processes described later. Examples of the portable recording medium 40 include a CD-ROM (Compact Disc Read Only Memory) and a DVD-ROM (Digital Versatile Disc Read Only Memory).

  In order to operate such a computer 30 as the router 5 or 6, first, a control program for causing the MPU 31 to perform the processing contents of the control processing described later is created. The created control program is stored in advance in the hard disk device 34 or the portable recording medium 40. Then, a predetermined instruction is given to the MPU 31 to read and execute the control program. In this way, the MPU 31 can function as the control unit 21, the input / output control unit 23, the communication control unit 24, and the clock control unit 25, and the hard disk device 34 can function as the storage unit 22. Operates as the router 5 or 6.

Next, the traffic volume control performed by the router 5 will be described with reference to FIG.
The router 5 that controls the traffic volume includes a token 50, a bucket 51, a release token bucket 52, a reception unit 53, a token granting unit 54, a transmission unit 55, a release token storage unit 56, and a token replenishment. Unit 57 and a transmission waiting buffer 58.

  The entity of the token 50 is, for example, predetermined specific data. As described above, the token 50 is associated with a predetermined data transmission amount. In the present embodiment, the total number of tokens 50 in the router 5 is determined in advance.

  The bucket 51 (first bucket) and the release token bucket 52 (second bucket) both hold the token 50, and are data buffers that store data that is the token 50, for example. In FIG. 3, the bucket 51 and the release token bucket 52 are configured as predetermined storage areas of the storage unit 22.

  Here, the receiving unit 53 receives a packet transmitted from the host system 1. The receiving unit 53 is an interface device controlled by the communication control unit 24 in FIG.

  The token granting unit 54 takes out the number of tokens 50 corresponding to the size of the packet received by the receiving unit 53 from the bucket 51 and gives it to the packet. However, when the number of tokens 50 held in the bucket 51 is not enough according to the size of the packet received by the receiving unit 53, the token granting unit 54 discards the packet. The function as the token granting unit 54 is provided by the control unit 21 in FIG.

  The transmission unit 55 transmits the packet provided with the token 50 by the token granting unit 54 to the host system 3 that is the destination of the packet. However, the transmission rate of the packet by the transmission unit 55 is a data communication rate allowed at the time of transmission in the communication between the host system 1 and the host system 3. Note that the transmission unit 55 does not transmit the token 50 attached to the packet. The transmission unit 55 is an interface device controlled by the communication control unit 24 in FIG.

  The release token storage unit 56 (first token storage unit) releases the token 50 attached to the packet transmitted by the transmission unit 55 from the packet, stores it in the release token bucket 52, and holds it. The function as the release token storage unit 56 is provided by the control unit 21 in FIG.

The token replenishment unit 57 (second token storage unit) takes out a predetermined number of tokens 50 held in the release token bucket 52 at a predetermined frequency, stores them in the bucket 51, and holds them. However, if the release token storage unit 56 cannot store the token 50 in the release token bucket 52 in time, the release token bucket 52 becomes empty (the token 50 is not held), and the token replenishment unit 57 extracts the token 50. Can not be. In this case, the token replenishment unit 57 suspends the retrieval of the token 50 from the release token bucket 52 and the storage in the bucket 51 until the release token storage unit 56 newly stores the token 50 in the release token bucket 52. .
The function as the token replenishing unit 57 is also provided by the control unit 21 in FIG.

  The transmission waiting buffer 58 is a buffer memory for temporarily storing a packet to which the token 50 is given by the token granting unit 54 when the transmission unit 55 cannot transmit the packet. The transmission waiting buffer 58 corresponds to the packet buffer 22-3 of the storage unit 22 in FIG.

The router 5 is configured as described above, and controls the flow rate of packets by this configuration. In this configuration, since the total number of tokens 50 in the router 5 is determined in advance, packets exceeding the data transmission amount corresponding to the total number of tokens 50 do not stay in the router 5. Accordingly, when the restriction on the transmission rate of packets allowed by the transmission unit 55 is relaxed, the packets staying in the router 5 are quickly resolved.
The traffic amount can be controlled by the router 6 instead of the router 5.

  By the way, the traffic amount control by the router 5 described with reference to FIG. 5 is performed using the token 50 that is actually present in the router 5 as data. Instead, by managing the packets to which tokens are given and managing the token amounts in the bucket 51 and the release token bucket 52, the traffic amount can be controlled without causing the token 50 to actually exist in the router 5. It is also possible to perform. Next, details of the traffic amount control performed in this way will be described.

First, FIG. 6 will be described. FIG. 6 illustrates a data structure example of the token amount management table 22-1 held in the storage unit 22 of FIG.
The token amount management table 22-1 is a table for managing the number of tokens held in the bucket 51 and the release token bucket 52 for the tokens 50 whose total number is predetermined.

  The token amount management table 22-1 includes items of “final calculation date and time”, “token amount in bucket at final calculation”, “waiting token amount at final calculation”, and “token generation rate”.

The “last calculated date” stores the latest date and time when each item of the token amount management table 22-1 is updated.
In the “final calculation token amount in bucket”, the calculation result of the token amount in the bucket 51 at “final calculation date” is stored.

In the “final calculation standby token amount”, the calculation result of the token amount of the release token bucket 52 at the “final calculation date and time” is stored.
The “token generation rate” stores the transfer speed of the token 50 from the release token bucket 52 to the bucket 51 when the token 50 is transferred from the release token bucket 52 to the bucket 51. The value of the transfer speed is set in advance by the administrator of the communication network in FIG.

  Next, FIG. 7 will be described. FIG. 7 illustrates an example of the data structure of a packet to which a token 50 is attached. In the packet buffer 22-3 prepared in the storage unit 22 of FIG. 3, each packet is stored in a state having the data structure of FIG.

  The entity of the packet to which the token 50 is assigned is stored in the “packet content” storage area in FIG. The data size of the “packet contents” is stored in the “packet size” storage area. Further, a packet ID which is identification information for individually identifying each packet is stored in the storage area of “packet ID”. The “packet size” and “packet ID” are information attached to the packet when the token granting unit 54 grants the token 50 to the packet.

Next, FIG. 8 will be described. FIG. 8 illustrates a data structure example of the token grant management table 22-2 held in the storage unit 22 of FIG.
A “packet ID” is stored in the token grant management table 22-2. When the token granting unit 54 grants a token 50 to a packet, the token granting unit 54 stores the packet ID given to the packet in the token granting management table 22-2.

Next, a control process performed by the control unit 21 when the traffic amount is controlled without causing the token 50 to actually exist in the router 5 will be described.
The control unit 21 corresponds to what is provided by each of the token granting unit 54, the released token storage unit 56, and the token supplementing unit 57 in FIG. 5 by performing the token granting process and the token releasing process described below. Provide functionality. In the case where the computer 30 whose configuration is illustrated in FIG. 4 is to function as the router 5, the control process described below is performed by the MPU 31 as described above.

  First, FIG. 9 will be described. FIG. 9 is a flowchart illustrating the processing contents of the first example of the token grant processing. This process is started each time the control unit 21 detects the reception of a new packet sent from the host system 1 via the communication control unit 24.

  In FIG. 9, first, in S101, the size of the received packet is obtained, and based on the obtained size, the number of tokens 50 (required token amount) corresponding to the data transmission amount when transmitting this received packet is calculated. Processing is performed.

Next, in S102, a process for calculating the token amount in the bucket 51 at this time is performed.
In this process, first, the clocking result of the date and time at this time is acquired from the clock control unit 25. Next, referring to the data content of the token amount management table 22-1 at this time, first, the elapsed time from the “last calculated date” in the table to the date acquired from the clock control unit 25 is calculated. Then, the transfer amount of the token 50 from the release token bucket 52 to the bucket 51 is calculated by multiplying the “token generation rate” in the table by this elapsed time. However, when the “waiting token amount at the time of final calculation” in the table is insufficient with respect to the calculation result, this “waiting token amount at the time of final calculation” is used as the token 50 from the release token bucket 52 to the bucket 51. The amount of transfer. By determining the transfer amount in this way, control is performed to interrupt the removal of the token 50 from the release token bucket 52 and the storage in the bucket 51 until the token 50 is newly stored in the release token bucket 52. .

  The smaller value of the multiplication result of the “token generation rate” and the elapsed time and the “waiting token amount at the time of final calculation” obtained as described above is used as the amount of tokens pumped from the release token bucket 52. It shall be called.

  Thereafter, the token amount in the bucket 51 at this time is calculated by adding the pumped token amount and the “final token amount in bucket at the time of final calculation” in the table.

  Next, in S103, processing for determining whether or not the number of tokens 50 to be given to the received packet is sufficient is performed. That is, it is determined whether or not the required token amount calculated in the process of S101 is equal to or less than the token amount in the bucket 51 calculated in the process of S102. Here, when it is determined that the required token amount is equal to or less than the token amount in the bucket 51 (when the determination result is “Yes”), the process proceeds to S104. On the other hand, when it is determined that the required token amount exceeds the token amount in the bucket 51 (when the determination result is “No”), the process proceeds to S108.

  Next, in S104, the process of adding the above-described “packet ID” and “packet size” (that is, the received packet obtained in the process of S101) to the received packet to obtain the data structure illustrated in FIG. Done. Then, in the subsequent S105, a process of storing the packet after the process of S104 in the packet buffer 22-3 prepared in the storage unit 22 is performed.

  Next, in S106, a process of adding the “packet ID” for the packet stored in the packet buffer 22-3 in the process of S105 to the token granting management table 22-2 prepared in the storage unit 22 and storing it. Done.

  Next, in S107, the token amount management table 22-1 is updated. In the process of S107, first, the data of “final calculation date” in the table is updated to the time measurement result of the date acquired from the clock control unit 25 in the process of S102. Next, the necessary token amount calculated in the processing of S101 is subtracted from the token amount in the bucket 51 calculated in the processing of S102, and the value of the subtraction result is “the token amount in the bucket at the time of final calculation” in the table. The data after the update. Then, the above-mentioned pumping token amount is subtracted from the “final calculation standby token amount” data in the table, and the value of the subtraction result is set to the updated value of the “final calculation standby token amount”. To do. Therefore, in the processing of S102 described above, when the pumped token amount is the “waiting token amount at the time of final calculation”, the updated value of the “waiting token amount at the time of final calculation” is zero.

By the processing in S107, control is performed to reduce the number of tokens 50 held in the bucket 51 in the token amount management table 22-1 by the number corresponding to the size of the received packet. Further, by the processing of S107, control is performed to decrease the number of tokens 50 held in the release token bucket 52 in the token amount management table 22-1 by a predetermined number at a predetermined frequency. Further, by the process of S107 taking into account the process of S102 described above, the control for increasing the number of tokens held in the bucket 51 in the token amount management table 22-1 by the decrease of the token 50 in the release token bucket 52 is performed. Done.
After the process of S107 is completed, the process of FIG. 9 ends.

  On the other hand, in S108 in FIG. 9, a process of discarding the received packet that is the start of the token granting process is performed. Therefore, when the number of tokens 50 held in the bucket 51 is less than the number corresponding to the size of the received packet by the processing in S103 and the processing in S108, the received packet is controlled to be discarded. Done.

Next, in S109, the token amount management table 22-1 is updated. In the process of S109, first, the data of “last calculated date” in the table is updated to the time measurement result of the date acquired from the clock control unit 25 in the process of S102. Next, here, the token amount in the bucket 51 calculated in the processing of S102 is used as data after updating the “token amount in bucket at the time of final calculation” in the table (without subtracting the required token amount). . Then, the above-mentioned pumping token amount is subtracted from the “final calculation standby token amount” data in the table, and the value of the subtraction result is set to the updated value of the “final calculation standby token amount”. To do.
After the process of S107 is completed, the process of FIG. 9 ends.

  Next, FIG. 10 will be described. FIG. 10 is a flowchart illustrating the processing contents of the first example of the token release processing. This process is started each time the communication control unit 24 controls the interface device to read and transmit the packet stored in the packet buffer 22-3 by the token grant process described above.

  In FIG. 10, first, in S201, the packet buffer 22-3 determines whether or not the “packet ID” assigned to the transmitted packet is stored in the token grant management table 22-2. Done. If it is determined that the “packet ID” is stored in the token granting management table 22-2 (when the determination result is “Yes”), the process proceeds to S202. On the other hand, when it is determined that the “packet ID” is not stored in the token grant management table 22-2 (when the determination result is “No”), the token release processing is terminated as it is.

  Next, in S202, the packet buffer 22-3 acquires "packet size" data attached to the transmitted packet, and calculates the number of tokens 50 corresponding to the value indicated by this data. Processing is performed. The number calculated by this processing will be referred to as the release token amount.

  Next, in S203, a process of deleting the “packet ID” discovered from the token grant management table 22-2 by the process of S201 from the token grant management table 22-2 is performed.

Next, in S204, a process for calculating the token amount in the bucket 51 at this time is performed.
The processing in S204 has the same processing contents as the processing in S102 of FIG. That is, first, the time measurement result of the date and time at this time is acquired from the clock control unit 25. Next, referring to the data content of the token amount management table 22-1 at this time, first, the elapsed time from the “last calculated date” in the table to the date acquired from the clock control unit 25 is calculated. Then, the transfer amount of the token 50 from the release token bucket 52 to the bucket 51 is calculated by multiplying the “token generation rate” in the table by this elapsed time. However, when the “waiting token amount at the time of final calculation” in the table is insufficient with respect to the calculation result, this “waiting token amount at the time of final calculation” is used as the token 50 from the release token bucket 52 to the bucket 51. The amount of transfer. In this way, the amount of tokens pumped from the release token bucket 52 is obtained. Then, the token amount in the bucket 51 at this time is calculated by adding the pumped token amount and the “final token amount in bucket at the time of final calculation” in the table.

Next, in S205, the token amount management table 22-1 is updated. In the process of S205, first, the data of “final calculation date” in the table is updated to the time measurement result of the date acquired from the clock control unit 25 in the process of S204. Next, the token amount in the bucket 51 calculated in the process of S204 is used as the data after updating the “token amount in bucket at the time of final calculation” in the table. Then, the above-mentioned pumped-up token amount is subtracted from the “waiting token amount at the time of final calculation” data in the table, and the above-mentioned released token amount is further added to the subtraction result. Then, the value calculated in this way is set as the updated value of the “final token amount at the time of final calculation”. By the processing of S205, control is performed to increase the number of tokens 50 held in the release token bucket 52 in the token amount management table 22-1 by the number of tokens 50 according to the size of the transmission packet.
After finishing the process of S205, the process of FIG.

  By performing the token granting process and the token releasing process, the control unit 21 controls the traffic amount similar to that described with reference to FIG. 5 without causing the token 50 to actually exist in the router 5. Can do.

The effect of performing the above traffic amount control will be described.
First, FIG. 11 will be described. FIG. 11 illustrates an example of a temporal change in the amount of packets received from the host system 1 and the amount of packets that can be transmitted to the host system 3 by the router 5.

  In this example, the amount of received packets is constant at a quantity rate x [/ second], whereas the amount of packet transmission is z [/ seconds] until time T # 0, then 0 until time T # 1, Thereafter, it is assumed that the time fluctuates with y [/ second] until time T # 2, and recovers to z [/ second] at T # 2. Note that z> x> y> 0.

In FIG. 12A, FIG. 12B, FIG. 12C, and FIG. 13 to be described below, it is assumed that the packet reception amount and the packet transmittable amount change with time as illustrated in FIG.
First, FIG. 12A will be described. FIG. 12A illustrates the state of packet retention and transmission in the router 5 when the router 5 controls the traffic volume according to the principle of the token bucket scheme illustrated in FIG.

  In this case, since the replenishment of the token 101 to the bucket 100 is continued even when the packet transmittable amount becomes zero at T # 0, the packet 111 is not discarded. For this reason, the staying amount of the packet 111 in the router 5 increases as time passes. After that, even if the packet transmittable amount recovers to y at T # 1, the recovery is less than the packet reception amount x, and the retention of the packet 111 in the router 5 further increases. Therefore, when the packet transmittable amount recovers to the original z at the subsequent time T # 2, the packet 111 that has stayed so far is discharged at a stretch, and a large amount of packets 111 are transmitted (a large amount of transmission exceeding the packet reception amount x). ) Will continue for a long time. At this time, the router 6 may be congested by a large number of packets 111.

  Next, FIGS. 12B and 12C will be described. FIG. 12B and FIG. 12C both illustrate packet retention and transmission when the traffic volume is controlled using the first technique described above.

  Attention is first directed to FIG. 12B. In the first technique described above, when the communication data throughput decreases at T # 1, in order to avoid excessive retention of communication data, the frequency of token output to the token buffer is decreased. Therefore, the stay of the packet 111 in the router 5 is temporarily suppressed. However, in the first technique described above, a predetermined amount of tokens are added to the token buffer and reduced after a predetermined time after the token buffer transitions to a depleted state, even if the communication data throughput does not recover. An operation for transitioning to a state is performed. For this reason, the retention amount of the packet 111 in the router 5 eventually increases with time. Therefore, if the packet transmittable amount recovers to the initial z at time T # 2, the packet 111 that has stayed until then is discharged at a stretch, as in the case of FIG. Large-volume transmission) will continue for a long time. At this time, the router 6 may be congested by a large number of packets 111.

  Here, the case where the addition of the token to the token buffer for transitioning the token buffer from the depleted state to the decreasing state is stopped is the case of FIG. 12C. In this way, the staying amount of the packet 111 in the router 5 is limited to a predetermined amount. However, after that, transmission of the packet 111 staying in the router 5 with the throughput y may be completed after time T # 1. In this case, the communication data throughput does not recover up to x, which is the same as the received packet amount, even if other factors such as increase in traffic are eliminated and the packet transmittable amount recovers to z. turn into.

  On the other hand, FIG. 13 illustrates the state of packet retention and transmission when the traffic amount is controlled by the router 5 having the configuration of FIG. In this case, the total amount of packets staying in the router 5 does not exceed the amount determined by the total number of tokens 50 set in advance. Accordingly, the mass transmission of the packets stored in the packet buffer 22-3, which is retained in the router 5, is completed in a short time. Further, if other factors such as an increase in traffic are solved thereafter and the packet transmittable amount is restored to the original z, the communication data throughput is also promptly restored to x which is the packet reception amount.

Next, some modified examples of the token grant process of FIG. 9 and the token release process of FIG. 10 described above will be described.
First, FIG. 14 will be described. FIG. 14 is a flowchart illustrating the processing contents of the second example of the token release processing.

  Even if the control unit 21 performs the token release process of FIG. 14 together with the token grant process of FIG. 9 instead of the token release process of FIG. 10, the same traffic as described with reference to FIG. The amount can be controlled.

  The process of FIG. 14 is started each time the communication control unit 24 controls the interface device to read and transmit the packet stored in the packet buffer 22-3 by the token grant process described above.

  The flowchart of FIG. 14 is obtained by replacing the processing of S204 and S205 in the flowchart of FIG. 10 with the processing of S211. Therefore, only the processing of S211 will be described here.

  In S211 following S203, a process is performed in which the released token quantity calculated in the process of S202 is added to the value of “waiting token quantity at the time of final calculation” in the token quantity management table 22-1, and the value is updated. The process of FIG. 14 ends.

  As described above, in the process of S211 described above, only the process of increasing the number of tokens 50 held in the release token bucket 52 in the token amount management table 22-1 by the number of tokens 50 according to the size of the transmitted packet. Is done. In other words, the token amount management table 22-1 corresponding to the pumping of the token 50 from the release token bucket 52 and the transfer to the bucket 51 is performed by the token granting process when the packet is received. Do not do it. By doing so, the processing amount for updating the token amount management table 22-1 is reduced, so that the processing load on the control unit 21 is reduced.

Next, FIG. 15 will be described. FIG. 15 is a flowchart illustrating the processing contents of the second example of the token grant processing.
Even if the control unit 21 performs the token grant process of FIG. 15 together with the token release process of FIG. 14 instead of the token grant process of FIG. 9, the same traffic as described with reference to FIG. The amount can be controlled.

The process of FIG. 15 is started each time the control unit 21 detects the reception of a new packet sent from the host system 1 via the communication control unit 24.
In the flowchart of FIG. 15, the process of S109 in the flowchart of FIG. 9 is deleted, and the token granting process is terminated after the process of S108. That is, the token amount management table 22-1 corresponding to the pumping of the token 50 from the release token bucket 52 and the transfer to the bucket 51 is performed by a token grant process when a packet is received. However, this update process is performed in S107 only when the determination result in S103 is Yes, and is not performed when the determination result in S103 is No. In other words, the token amount management table 22-1 is updated only when the number of tokens 50 held in the bucket 51 in the token amount management table 22-1 is equal to or greater than the number according to the size of the received packet. Is what you want to do. In this way, the processing amount for updating the token amount management table 22-1 is further reduced, so that the processing load on the control unit 21 is further reduced.

  Note that the token amount management table 22-1 described above may be updated at a predetermined cycle regardless of the packet transmission / reception timing instead of being performed at the time of packet reception or packet transmission. In order to do this, the control unit 21 performs a third example of the token granting process of FIG. 16 to be described below together with the token release process of FIG. 14, and in parallel with this, FIG. The control unit 21 may perform the token pumping process.

FIG. 16 will be described. FIG. 16 is a flowchart illustrating the processing contents of the third example of the token grant processing.
The process of FIG. 16 is started each time the control unit 21 detects the reception of a new packet sent from the host system 1 via the communication control unit 24.

  The flowchart of FIG. 16 is obtained by replacing the processes of S102 and S107 in the flowchart of FIG. 15 with processes of S111 and S112, respectively. Therefore, only the processes of S111 and S112 will be described here.

  In S111 following S101, processing for obtaining the value of “the token amount in the bucket at the time of final calculation” is performed with reference to the data content of the token amount management table 22-1 at this time. In the determination process of S103 following this process, the value acquired in this process is used as the token amount in the bucket 51.

  On the other hand, in S112 following S106, a process of updating only the data of “the token amount in the bucket at the time of final calculation” in the token amount management table 22-1 is performed. That is, the required token amount acquired in the processing of S101 is subtracted from the token amount in the bucket 51 acquired in the above-described processing of S111, and the value of this subtraction result is “at the time of final calculation” in the token amount management table 22-1. The processing of “the amount of tokens in the bucket” is performed. And after finishing this process, the process of this FIG. 16 is complete | finished.

  Accordingly, in the process of S112, only the process of reducing the number of tokens 50 held in the bucket 51 in the token amount management table 22-1 by the number corresponding to the size of the received packet is performed. That is, the token amount management table 22-1 corresponding to the pumping of the token 50 from the release token bucket 52 and the transfer to the bucket 51 is not performed in this token granting process, and also in the token releasing process of FIG. Not done.

Next, FIG. 17 will be described. FIG. 17 is a flowchart illustrating the processing contents of the token pumping processing.
The process of FIG. 17 is started when the control unit 21 receives the time measurement result every time the clock control unit 25 measures the elapse of the predetermined time, more specifically, the predetermined time.

  In FIG. 17, first, in S301, the above-described pumping token amount calculation process is performed. That is, first, the time measurement result of the date and time at this time is acquired from the clock control unit 25. Next, referring to the data content of the token amount management table 22-1 at this time, first, the elapsed time from the “last calculated date” in the table to the date acquired from the clock control unit 25 is calculated. Then, the transfer amount of the token 50 from the release token bucket 52 to the bucket 51 is calculated by multiplying the “token generation rate” in the table by this elapsed time. However, when the “waiting token amount at the time of final calculation” in the table is insufficient with respect to the calculation result, this “waiting token amount at the time of final calculation” is used as the token 50 from the release token bucket 52 to the bucket 51. The amount of transfer. The transfer amount of the token 50 from the release token bucket 52 to the bucket 51 obtained as described above is set as a pumping token amount from the release token bucket 52.

Next, in S302, the token amount management table 22-1 is updated. In the process of S302, first, the data of “last calculated date” in the table is updated to the time measurement result of the date acquired from the clock control unit 25 in the process of S301. Next, the above-mentioned pumping token amount is added to the data of “the token amount in the bucket at the time of final calculation” in the table, and the value of the addition result is the updated value of the “amount of token in the bucket at the time of final calculation”. And Then, the above-mentioned pumping token amount is subtracted from the “final calculation standby token amount” data in the table, and the value of the subtraction result is set to the updated value of the “final calculation standby token amount”. To do.
After finishing the process of S302, the process of FIG.

  Even if the control unit 21 performs the token granting process of FIG. 16, the token releasing process of FIG. 14, and the token pumping process of FIG. 17 in parallel, the same as described with reference to FIG. 5. The amount of traffic can be controlled.

In addition, the following additional remarks are disclosed regarding the embodiment described above.
(Appendix 1)
A token amount management table that manages the number of tokens held in each of the first bucket and the second bucket that hold the tokens with a predetermined total number;
Receiving means for receiving communication data packets;
Token amount reducing means for reducing the number of tokens held in the first bucket in the token quantity management table by the number corresponding to the size of the communication data packet received by the receiving means;
Transmitting means for transmitting the communication data packet received by the receiving means;
Token amount increasing means for increasing the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmitting means;
The token amount management table is updated to reduce the number of tokens held in the second bucket in the token amount management table by a predetermined number at a predetermined frequency, and the tokens in the first bucket in the token amount management table A token amount updating means for increasing the number of stored tokens by the decrease,
Have
When the number of tokens held in the first bucket in the token amount management table is less than the number according to the size of the communication data packet received by the receiving unit, the token amount subtracting unit Maintaining the number of tokens held in the first bucket in the table, and discarding the communication data packet without causing the transmission means to transmit.
A communication device.
(Appendix 2)
When the number of tokens held in the second bucket in the token amount management table is insufficient with respect to the predetermined number, the token amount update unit is equal to the number of tokens held in the second bucket, The number of tokens held in the first bucket in the token amount management table is increased, and the number of tokens held in the second bucket in the token amount management table is set to zero. Thereafter, the token amount increasing means The communication apparatus according to appendix 1, wherein updating of the number of tokens held in the second bucket and the first bucket in the token amount management table is interrupted until the number of held tokens is increased.
(Appendix 3)
The communication apparatus according to appendix 1 or 2, wherein the token amount changing unit updates the token amount management table when the receiving unit receives a communication data packet.
(Appendix 4)
The token amount changing means, when the number of tokens held in the first bucket in the token amount management table is not more than the number according to the size of the communication data packet received by the receiving means, The communication apparatus according to appendix 3, wherein the management table is updated.
(Appendix 5)
The communication apparatus according to appendix 1 or 2, wherein the token amount changing unit updates the token amount management table at a predetermined cycle.
(Appendix 6)
A traffic amount control method performed using a communication device having a receiving means for receiving a communication data packet and a transmitting means for transmitting the communication data packet,
The number of tokens held in the first bucket in the token amount management table for managing the number held in each of the first bucket and the second bucket for the tokens whose total number is predetermined, A token amount reduction step for reducing the number of communication data packets received by the receiving means by the number of the communication data packets;
A token amount increasing step for increasing the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmitting unit;
The token amount management table is updated, and the number of tokens held in the second bucket in the token amount management table is decreased by a predetermined number at a predetermined frequency, and the number of tokens in the first bucket in the token amount management table is decreased. A token amount update step for increasing the number of held items by the decrease, and
Have
If the number of tokens held in the first bucket in the token amount management table is less than the number according to the size of the communication data packet received by the receiving means, the token amount reducing step Maintaining the number of tokens held in the first bucket in the management table and discarding the communication data packet without causing the transmission means to transmit
A traffic amount control method characterized by the above.
(Appendix 7)
In the token quantity update step, when the number of tokens held in the second bucket in the token quantity management table is zero, the token quantity management table until the number of held tokens is increased by the token quantity increase step. The traffic amount control method according to appendix 6, wherein updating of the second bucket and the number of tokens held in the first bucket is interrupted.
(Appendix 8)
A program for causing an arithmetic processing unit to control the amount of traffic performed using a communication apparatus having a receiving means for receiving a communication data packet and a transmitting means for transmitting the communication data packet,
The number of tokens held in the first bucket in the token amount management table for managing the number held in each of the first bucket and the second bucket for the tokens whose total number is predetermined, Token amount reduction processing for reducing the number according to the number of communication data packets received by the receiving means;
Token amount increase processing for increasing the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmission means;
The token amount management table is updated, and the number of tokens held in the second bucket in the token amount management table is decreased by a predetermined number at a predetermined frequency, and the number of tokens in the first bucket in the token amount management table is decreased. Token amount update processing to increase the number of holdings by the decrease,
To the arithmetic processing unit,
When the number of tokens held in the first bucket in the token amount management table is less than the number according to the size of the communication data packet received by the receiving unit, Maintaining the number of tokens held in the first bucket in the management table and discarding the communication data packet without causing the transmission means to transmit
A program characterized by that.
(Appendix 9)
In the token amount update processing, when the number of tokens held in the second bucket in the token amount management table is zero, the token amount management table until the number of held tokens is increased by the token amount increase processing. 9. The program according to appendix 8, wherein the updating of the second bucket and the number of tokens held in the first bucket is interrupted.
(Appendix 10)
A predetermined number of tokens;
A first bucket and a second bucket holding the token;
Receiving means for receiving communication data packets;
Token giving means for taking out the number of tokens corresponding to the size of the communication data packet received by the receiving means from the first bucket and giving the token to the communication data packet;
Transmitting means for transmitting the communication data packet to which the token is attached by the token attaching means;
First token storage means for storing and holding the token attached to the communication data packet transmitted by the transmission means in the second bucket;
Second token storage means for taking out the token held in the second bucket at a predetermined frequency, storing it in the first bucket, and holding it;
Have
The token granting unit discards the communication data packet when the number of tokens held in the first bucket is less than the number corresponding to the size of the communication data packet received by the receiving unit.
A communication device.
(Appendix 11)
If the second token storage means does not hold a token in the second bucket, the second token storage means stores the token from the second bucket until the first token storage means newly stores a token in the second bucket. The communication device according to appendix 10, wherein the take-out and storage in the first bucket are interrupted.

1, 2, 3, 4 Host system 5, 6 Router 11, 21 Control unit 12, 22 Storage unit 13, 23 Input / output control unit 14, 24 Communication control unit 22-1 Token amount management table 22-2 Token grant table 22 -3 Packet buffer 25 Clock control unit 30 Computer 31 MPU
32 ROM
33 RAM
34 Hard Disk Device 35 Input Device 36 Display Device 37 Interface Device 38 Recording Medium Drive Device 39 Bus 40 Portable Recording Medium 50, 101 Token 51, 100 Bucket 52 Release Token Bucket 53 Receiving Unit 54 Token Granting Unit 55 Transmitting Unit 56 Free Token Storage Part 57 token replenishment part 58 transmission waiting buffer 110 packet control point 111 packet

Claims (8)

A token amount management table that manages the number of tokens held in each of the first bucket and the second bucket that hold the tokens with a predetermined total number;
Receiving means for receiving communication data packets;
Token amount reducing means for reducing the number of tokens held in the first bucket in the token quantity management table by the number corresponding to the size of the communication data packet received by the receiving means;
Transmitting means for transmitting the communication data packet received by the receiving means;
Token amount increasing means for increasing the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmitting means;
The token amount management table is updated to reduce the number of tokens held in the second bucket in the token amount management table by a predetermined number at a predetermined frequency, and the tokens in the first bucket in the token amount management table A token amount updating means for increasing the number of stored tokens by the decrease,
Have
Holding the number of tokens in said first bucket in the amount of token management table, if less than the number of said receiving means corresponding to the size of the communication data packet received, said token amount reducing means, said amount of token Maintaining the number of tokens held in the first bucket in the management table, and discarding the communication data packet without causing the transmission means to transmit.
A communication device.   When the number of tokens held in the second bucket in the token amount management table is insufficient with respect to the predetermined number, the token amount update unit is equal to the number of tokens held in the second bucket, The number of tokens held in the first bucket in the token amount management table is increased, and the number of tokens held in the second bucket in the token amount management table is set to zero. Thereafter, the token amount increasing means The communication apparatus according to claim 1, wherein updating of the number of tokens held in the second bucket and the first bucket in the token amount management table is interrupted until the number of held tokens is increased. 3. The communication apparatus according to claim 1, wherein the token amount updating unit updates the token amount management table when the receiving unit receives a communication data packet. The amount of token updating means, holding the number of tokens in said first bucket in the token management table is only the case of equal to or more than the number of said receiving means corresponding to the size of the communication data packet received, the token The communication apparatus according to claim 3, wherein the amount management table is updated. The communication apparatus according to claim 1, wherein the token amount update unit updates the token amount management table at a predetermined cycle. A traffic amount control method performed using a communication device having a receiving means for receiving a communication data packet and a transmitting means for transmitting the communication data packet,
The number of tokens held in the first bucket in the token amount management table for managing the number held in each of the first bucket and the second bucket for the tokens whose total number is predetermined, A token amount reduction step for reducing the number of communication data packets received by the receiving means by the number of the communication data packets;
A token amount increasing step for increasing the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmitting unit;
The token amount management table is updated, and the number of tokens held in the second bucket in the token amount management table is decreased by a predetermined number at a predetermined frequency, and the number of tokens in the first bucket in the token amount management table is decreased. A token amount update step for increasing the number of held items by the decrease, and
Have
If the number of tokens held in the first bucket in the token amount management table is less than the number according to the size of the communication data packet received by the receiving means, the token amount reducing step Maintaining the number of tokens held in the first bucket in the management table and discarding the communication data packet without causing the transmission means to transmit
A traffic amount control method characterized by the above. A program for causing an arithmetic processing unit to control the amount of traffic performed using a communication apparatus having a receiving means for receiving a communication data packet and a transmitting means for transmitting the communication data packet,
The number of tokens held in the first bucket in the token amount management table for managing the number held in each of the first bucket and the second bucket for the tokens whose total number is predetermined, Token amount reduction processing for reducing the number according to the number of communication data packets received by the receiving means;
Token amount increase processing for increasing the number of tokens held in the second bucket in the token amount management table by the number corresponding to the size of the communication data packet transmitted by the transmission means;
The token amount management table is updated, and the number of tokens held in the second bucket in the token amount management table is decreased by a predetermined number at a predetermined frequency, and the number of tokens in the first bucket in the token amount management table is decreased. Token amount update processing to increase the number of holdings by the decrease,
To the arithmetic processing unit,
Holding the number of tokens in said first bucket in the amount of token management table, if less than the number of said receiving means corresponding to the size of the communication data packet received is in the amount of token down increase process, the token Maintaining the number of tokens held in the first bucket in the amount management table and discarding the communication data packet without causing the transmission means to transmit
A program characterized by that. A predetermined number of tokens;
A first bucket and a second bucket holding the token;
Receiving means for receiving communication data packets;
Token giving means for taking out the number of tokens corresponding to the size of the communication data packet received by the receiving means from the first bucket and giving the token to the communication data packet;
Transmitting means for transmitting the communication data packet to which the token is attached by the token attaching means;
First token storage means for storing and holding the token attached to the communication data packet transmitted by the transmission means in the second bucket;
Second token storage means for taking out the token held in the second bucket at a predetermined frequency, storing it in the first bucket, and holding it;
Have
The token granting unit discards the communication data packet when the number of tokens held in the first bucket is less than the number corresponding to the size of the communication data packet received by the receiving unit.
A communication device.