JP2008005096A - Apparatus, method and program for traffic control using token bucket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for traffic control which controls a token rate, according to the state of a network. <P>SOLUTION: The apparatus for traffic control comprises a token buffer monitoring means of monitoring tokens held in a token buffer, a speed information acquiring means of acquiring link speed information regarding communication speed which can be set for a link used for connection with the network, a connection link congestion information acquiring means of acquiring connection link congestion information that shows how the link connected to the network is congested, and a rate determining means of determining the value of the token rate after updating, on the basis of the link speed information and connection link congestion information, in a state of the tokens being held in the token buffer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a traffic control technique using a token bucket.

  As one of traffic control systems in communication apparatuses, a system called a token bucket has been proposed and used (for example, see Non-Patent Document 1). FIG. 4 is a block diagram of traffic control using a token bucket, which is provided on the transmission side and / or reception side of the communication apparatus.

  Here, the application of the communication device to the transmission side is aimed at direct control of traffic transmitted from the communication device to the network, and the application to the reception side is indirect traffic transmitted from the opposite communication device to the network. For control purposes. In other words, it is intended to restrict the data to be taken into the communication device on the receiving side, so that the flow control in the upper layer works, and thus the traffic transmitted from the opposite communication device to the network is restricted.

  According to FIG. 4, the traffic control by the token bucket includes a token generation unit 11, a token buffer 12, a reading unit 13, and a data buffer 14.

  The token generation unit 11 generates a predetermined number of tokens 10 (hereinafter referred to as a token output number) in a certain cycle (hereinafter referred to as a token output cycle) and outputs the token buffer 12 to the token buffer 12. 11 holds the token 10 generated. On the other hand, the data buffer 14 is a buffer that holds the data 20. In the case of traffic control on the transmission side of the communication apparatus, the data 20 is data or a packet transmitted to the network. In the case of traffic control on the reception side of the communication apparatus, the data 20 is data or a packet received from the network. It is output to other functional blocks in the device, a common bus, or the like.

  The token 10 is a right to read, and each time the reading unit 13 consumes one token 10 held in the token buffer 12, a predetermined amount of data 20 such as 1 bit or 1 byte is read from the data buffer 14. Read and output. Here, the amount of data (bits / piece) that can be read from the data buffer 14 each time one token 10 is consumed, the token output period (times / second) by the token generator 11, and the number of token outputs (pieces / piece). The product of times) is hereinafter referred to as a token rate. That is, the token rate is a value equal to the average value of the reading speed of the data 20 by the reading unit 13 when the amount of the data 20 is sufficient.

  In the traffic control using the token bucket, when the data 20 to be output is small, the unused token 10 is stored in the token buffer 12, so the reading unit 13 temporarily reads the data 20 at a speed exceeding the token rate. There is a feature that is possible.

A. Parekh, R.A. Gallerger, “A generalized processor sharing approach to flow control in integrated services network: the single node ensemble et. 1, no. 3. January 1993

  In the traffic control using the token bucket, determination of the set value of the token rate becomes a problem. In other words, if the token rate is too high, it is equivalent to not performing any traffic control, and if the token rate is too low, only a small amount of data can be transmitted / received even though there is a surplus bandwidth. End up.

  Therefore, an object of the present invention is to provide a traffic control device, method, and program for controlling the token rate according to the state of the network.

According to the traffic control device of the present invention,
A data buffer for holding data; a rate determining means for determining a token rate and updating the token output period and / or the number of token outputs based on the determined token rate; and for the number of token outputs for each token output period A token generator that outputs an equal number of tokens, a token buffer that holds the token output by the token generator, and reads out a predetermined amount of data from the data buffer each time the token held in the token buffer is consumed Means, a token buffer monitoring means for monitoring a token held in the token buffer, a speed information obtaining means for obtaining link speed information that is a communication speed applicable to a connection link with the network, and a connection link with the network Connection link congestion information indicating the congestion level of A connection link congestion information acquisition means for determining a value after updating the token rate based on the link speed information and the connection link congestion information in a state where the token is held in the token buffer. Features.

According to another embodiment of the traffic control device of the present invention,
The connection link congestion information is also preferably the number of reserved channels, which is the number of communication devices sharing the connection link with the network.

According to another embodiment of the traffic control device of the present invention,
The connection link congestion information is also preferably a ratio between the assignable radio resource amount and the assigned radio resource amount.

Furthermore, according to another embodiment of the traffic control device of the present invention,
The connection link congestion information is also preferably a radio resource usage amount of a communication apparatus sharing a radio link, which is notified from a base station which is a radio link setting destination.

Furthermore, according to another embodiment of the traffic control device of the present invention,
It is also preferable that a radio link based on a code division multiple access method is used for connection to the network, and the radio resource usage amount is noise power due to an interference signal from a communication device sharing the radio link.

Furthermore, according to another embodiment of the traffic control device of the present invention,
It is also preferable that the rate determining unit decreases the determined token rate as the degree of congestion increases.

Furthermore, according to another embodiment of the traffic control device of the present invention,
The reading unit preferably stops reading data from the data buffer when the degree of congestion is equal to or greater than a predetermined value.

According to the traffic control method of the present invention,
A traffic control method using a token bucket in a communication device, the step of acquiring link speed information that is a communication speed applicable to a connection link with a network, and connection link congestion information indicating a degree of congestion of the connection link with the network And a token rate is determined based on link speed information and connection link congestion information in a state where the token is held in the token buffer.

  According to the program of the present invention, a computer is caused to function as the traffic control device.

  Traffic control considering the number of communication devices sharing communication resources is possible by determining the token rate based on link speed information and connection link congestion information when traffic control by token bucket is not performed. .

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. FIG. 2 shows a communication system composed of a plurality of mobile devices connected to the base station by radio links, and the traffic control device according to the present invention is applied to the mobile device of FIG.

  FIG. 1 is a block diagram of a traffic control device according to the present invention, showing a configuration when applied to a receiving side. According to FIG. 1, the traffic control device includes a token generation unit 1, a token buffer 2, a reading unit 3, a data buffer 4, a speed information acquisition unit 5, a connection link congestion information acquisition unit 6, and a token buffer monitor. Unit 7 and rate determining unit 8.

  The token generation unit 1 generates a number of tokens 10 equal to the number of token outputs for each token output period and outputs the tokens 10 to the token buffer 2. The rate determination unit 8 determines the token output period and / or the number of token outputs as described later. The token buffer 2 is a buffer that holds the token 10 generated by the token generation unit 1, and the data buffer 4 is a buffer that holds data 20 received from the network.

  The reading unit 3 reads a predetermined amount of data 20 from the data buffer 4 and outputs it every time one token 10 held in the token buffer 2 is consumed.

  The speed information acquisition unit 5 acquires link speed information that is a speed applicable to a connection link with the network. The link speed information can be obtained either by using the link speed connected to the network as it is or by directly receiving a link speed value that can be set from the network. A method using values may be used. In this embodiment, the link is obtained by multiplying the number of slots allocated by the base station per unit time by the reception bit rate that can be realized in one slot, which is calculated by observing the pilot signal transmitted by the base station. Get speed information. Note that the number of slots allocated per unit time is normally determined by the base station of the mobile communication network based on the data transfer request amount for a plurality of mobile devices connected to the base station, and is notified to each mobile device. The speed information acquisition unit 5 notifies the rate determination unit 8 of the acquired link speed information.

  The connection link congestion information acquisition unit 6 acquires connection link congestion information indicating the degree of congestion of the connection link with the network from the network, and notifies the rate determination unit 8 of the acquired connection link congestion information. An example of connection link congestion information is the number of reserved channels, which is the number of communication devices sharing a radio link, and this information is normally transmitted from a base station in a mobile communication network to a mobile device. Further, the ratio of the total amount of radio resources that can be allocated to the mobile device, such as time slots and frequency bands, and the amount of radio resources actually allocated to the own device can be used.

  Furthermore, as the connection link congestion information, the radio resource usage of the communication device sharing the radio link, which is notified from the base station that is the radio link setting destination, particularly when the code division multiple access method is used as the radio link Can also be noise power due to interference signals from mobile devices sharing radio resources. In this case, the base station notifies the mobile device of a value obtained by quantizing the sum of power amounts of signals from other mobile devices that are interference signals to a certain mobile device with a plurality of bits.

  The token buffer monitoring unit 7 monitors whether the token 10 is held in the token buffer 2 and outputs it to the rate determining unit 8. Note that the token 10 being held in the token buffer 2 is a state in which traffic restriction by the token bucket is not performed, and thereafter, the token 10 is held in the token buffer 2, contrary to the non-restricted state. The absence is a state in which traffic restriction is performed by the token bucket, and is hereinafter referred to as a restriction state. FIG. 3 is a diagram illustrating the relationship between the amount of tokens held in the token buffer 2 and each state.

  The rate determination unit 8 determines the token rate based on the link speed information from the speed information acquisition unit 5 in the unrestricted state and the connection link congestion information from the connection link congestion information acquisition unit 6, and updates the determined token rate The subsequent token output period and / or the number of token outputs are calculated and notified to the token generator 1. Here, the product (number / second) of the token output cycle (times / second) and the number of token outputs (number / time) uses the determined token rate (bit / second), and the reading unit 3 consumes one token 10. It is obtained by dividing by the amount of data (bits / piece) read from the data buffer 4 each time. The rate determination unit 8 determines the updated token output cycle and the number of token outputs from the product of the token output cycle and the number of token outputs. However, the token output number can be changed by changing only the token output number with the token output cycle fixed. The method may be a method of changing only the token output period while fixing the token output period, or a method of changing both the token output period and the number of token outputs. When the token output cycle or the number of token outputs is fixed, only one variable value is notified to the token generation unit 1. Note that, for example, when using throughput or the like for link speed information, only the value in the unrestricted state is tokenized in order to avoid using the throughput limited by the token bucket to determine a new token rate value. Used to determine the rate. The token rate is updated when the non-restricted state is changed to the restricted state. However, when the non-restricted state continues for a predetermined time or more, the token rate may be updated every predetermined time.

Here, the updated token rate determined by the rate determining unit 8 is B, where the average value of the link speed information in the unrestricted state is B.
Updated token rate = B x Y
Ask for. Here, Y is a parameter corresponding to the average value of the congestion level indicated by the connection link congestion information in the unrestricted state. The following is a numerical example when the number of reserved channels is used as connection link congestion information.

更新後のトークンレートは、非制限状態におけるリンク速度情報の平均値を、保留チャネル数に応じた１以下のパラメータにより減少させたものである。表１に示す様に、保留チャネル数が多いほど、つまり、同一基地局と通信している移動機数が多いほど、Ｙの値を小さくしてトークンレートを制限するため、同一基地局と通信している移動機数を考慮したトラヒック制御を行うことができる。

The updated token rate is obtained by reducing the average value of the link speed information in the unrestricted state by a parameter of 1 or less corresponding to the number of reserved channels. As shown in Table 1, as the number of reserved channels increases, that is, as the number of mobile devices communicating with the same base station increases, the value of Y is reduced to limit the token rate. Traffic control can be performed in consideration of the number of mobile devices in operation.

  Also, when the number of reserved channels exceeds a certain threshold, 45 in Table 1, the reading control from the data buffer 4 by the reading unit 3 is forcibly stopped, and the opposite communication is performed by the flow control in the upper layer. Stop sending data to the network by the device. As a result, when a large number of mobile devices are communicating with the same base station, the load on the network can be reduced.

  As for the link speed information and connection link congestion information used for token rate update, only the values acquired during the fixed period from when the non-restricted state is entered, or the fixed period from when the non-restricted state enters the restricted state It is not necessary to use all the values notified from the speed information acquisition unit 5 and the connection link congestion information acquisition unit 6 in the non-restricted state as in the case of only the values acquired during May be limited to Furthermore, instead of the average value, the notified value itself may be used like the value notified at the end of the unrestricted state.

Next, application of the traffic control device according to the present invention to the transmission side will be described. Usually, since the base station does not notify the mobile device of information related to the reception state at the base station, the speed information acquisition unit 5 uses the average value S of its own throughput in an unrestricted state,
Updated token rate = S x Y
Determine as. Here, Y is a parameter corresponding to the connection link congestion information as shown in Table 1 as described in the application to the receiving side.

  As described above, the number of communication devices sharing communication resources is determined by determining the token rate based on link speed information and connection link congestion information in an unrestricted state, that is, in a state where traffic control by token bucket is not performed. Considerable traffic control is possible. Note that the present invention is applicable not only to a wireless system but also to a wired system as long as the number of communication devices sharing a communication resource can be acquired by the traffic control device.

It is a block diagram of the traffic control apparatus by this invention. It is a state transition diagram which a rate determination part manages. It is a figure which shows the relationship between each state, a token rate, and a throughput. It is a block diagram of traffic control by a token bucket.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Token 20 Data 1, 11 Token generation part 2, 12 Token buffer 3, 13 Reading part 4, 14 Data buffer 5 Speed information acquisition part 6 Connection link congestion information acquisition part 7 Token buffer monitoring part 8 Rate determination part

Claims (9)

A data buffer to hold the data,
Rate determining means for determining a token rate and updating the token output period and / or the number of token outputs based on the determined token rate;
Token generating means for outputting a number of tokens equal to the number of token outputs for each token output period;
A token buffer that holds the token output by the token generating means;
Reading means for reading a predetermined amount of data from the data buffer each time the token held in the token buffer is consumed;
Token buffer monitoring means for monitoring tokens held in the token buffer;
Speed information acquisition means for acquiring link speed information, which is a communication speed applicable to a connection link with a network;
Connection link congestion information acquisition means for acquiring connection link congestion information indicating the degree of congestion of the connection link with the network;
With
The rate determining means determines a value after updating the token rate based on link speed information and connection link congestion information in a state where the token is held in the token buffer.
A traffic control device characterized by the above. The connection link congestion information is the number of reserved channels, which is the number of communication devices sharing the connection link with the network.
The traffic control device according to claim 1. The connection link congestion information is the ratio of the assignable radio resource amount and the assigned radio resource amount,
The traffic control device according to claim 1. The connection link congestion information is a radio resource usage amount of a communication device sharing a radio link, which is notified from a base station that is a radio link setting destination,
The traffic control device according to claim 1. For connection to the network, a wireless link using the code division multiple access method is used,
Radio resource usage is noise power due to interference signals from communication devices sharing a radio link,
The traffic control device according to claim 4. The rate determination means reduces the token rate to be determined as the degree of congestion increases,
The traffic control device according to any one of claims 1 to 5, wherein: The reading means stops reading data from the data buffer when the degree of congestion is a predetermined value or more;
The traffic control device according to any one of claims 1 to 6, wherein A traffic control method using a token bucket in a communication device,
Obtaining link speed information, which is a communication speed applicable to a connection link with a network;
Obtaining connection link congestion information indicating the degree of congestion of the connection link with the network;
Have
Determining the token rate based on link speed information and connection link congestion information in a state where the token is held in the token buffer;
A traffic control method characterized by the above.   A program that causes a computer to function as the traffic control device according to any one of claims 1 to 7.

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