KR0175734B1 - Average traffic throughput control method in atm network - Google Patents

Abstract

According to the present invention, the average transmission rate of the user parameter control (UPC) method, which is one of the traffic control technologies, is controlled. A method of controlling the traffic rate, wherein the storage capacity is increased by adding the storage capacity remaining when fewer than average cells are passed in this window to the first storage location at the next window execution, thereby increasing the storage capacity by that amount. Even if a cell is input, it is possible to store all the cells, thereby reducing the number of discarded cells through flexible handling of respective services having various data rates.

Description

Average Traffic Rate Control Method in Asynchronous Transfer Mode (ATM) Network

The present invention relates to a method for controlling an average traffic rate in an asynchronous transmission mode (hereinafter referred to as ATM) network, and in particular, to control an average rate of a user parameter control (UPC) method, which is one of traffic control technologies. In addition, the present invention relates to an average traffic rate control method in an asynchronous transmission mode network in which a part of the storage capacity can be changed to obtain the maximum storage effect with the same total storage capacity.

In general, the ATM network transmits data in 53-byte cells according to user's transmission request, which can flexibly accommodate various transmission rates and various services that vary in time through statistical multiplexing. It is widely recognized as having advantages.

However, since it is difficult to accurately predict the change in the amount of transmission from these services when supporting a variable transmission rate, excessive traffic delays and cell loss occur when the traffic volume is congested from all services at one instant.

For example, services such as voice and high resolution video require low cell loss probability and short transmission delay. Thus, such a phenomenon is a decisive factor for degrading service quality.

Therefore, in order to guarantee the quality of service for each of the various services, an effective traffic control technique is required to prevent this phenomenon. Such traffic control techniques include call admission control (Connection Admission) related to the acceptance of a call establishment request. Control: CAC) and user parameter control that monitors and handles traffic passing through established connection are typical.

Many kinds of user parameter control methods have been proposed so far, and most of them are based on the 'LB (Leaky Bucket)' and 'JW (Jumping Window)' methods. Each of the above methods has their own advantages and disadvantages, but in general, the 'LB method' has been known to be the most effective method.

However, since the 'LB method' does not allow statistical multiplexing, there is a problem that efficiency is inferior. In order to overcome this problem, some problems have been solved by placing a buffer in the input part, but this is not satisfactory.

In conclusion, the 'LB' technique has some effects on the control of the maximum transmission rate of traffic, but it is not very effective on the average transmission rate.

Accordingly, several methods have been proposed in order to effectively control the average data rate. The L, M, and T methods and the PJW (Pseudo JW) methods are representative examples.

The 'L, M, and T' method is a modified form of the 'LB' and compares the actual mean rate in recent k bursts with the negotiated mean rate agreed upon in call setup. The average transmission rate is controlled by determining the interval with the next burst.

The 'PJW method' is a method based on the 'JW method', which allows a long-term fluctuation to some extent using a pseudo queue, but not much performance improvement in all of the above methods.

On the other hand, the nature of the traffic is expressed through a traffic descriptor (traffic descriptor), which includes the maximum transmission rate, the average transmission rate, the burst (burstiness) of the traffic. However, since it is not easy to define and handle the above items, only the maximum transmission rate is currently addressed by the International Telecommunication Union (ITU). However, the average transmission rate and the degree of burst must also be dealt with in the inspection technique. If the average transmission rate is not properly inspected, the following problems may occur.

First, there is a problem with fairness.

That is, from the perspective of the subscriber using the ATM network, the subscriber who transmits a lot of traffic has to pay a lot of fees. If the average transmission rate is not properly inspected, the subscriber can pay a lot of fees while transmitting a lot of traffic.

Second, there is a high possibility of causing excessive concentration.

Although it does not directly cause excessive condensation as in the case of violating the maximum data rate, there is a high possibility of collision with other cells since there are many cells within a certain interval. In other words, the possibility of buffer area overflow at the nodes in the network increases. And this has a problem in that the maximum rate of its own is increased by the jitter experienced in the nodes, that is, the possibility of narrowing the interval between cells increases.

In order to solve the conventional problems as described above, in the present invention, after setting the upper limit and the lower limit in the total storage place of the sum of the first storage place and pseudo Q, the cell input for each window is larger than the set average value. By variably adjusting the upper limit value of the first storage location in a window executed in the next step according to a large or small input state, it is possible to flexibly change the existing total cell storage capacity according to the situation and make the best use of it. The purpose is to.

1 is a schematic illustration of an average traffic rate control method according to the present invention.

2 is a flow chart showing the flow of the average traffic rate control method according to the present invention.

* Explanation of symbols for main parts of the drawings

10: cell 20: total storage

21: First Repository 22: Doctor's Queue

23, 24, 25, 26: window a: upper limit

b: lower limit

In order to achieve the above object, in the asynchronous transmission mode (ATM) network proposed in the present invention, the average traffic control method includes determining whether a currently running service is the end of a window. Calculating an upper limit value, increasing a service time when the window is not at the end of the window, and initializing a check flag of whether a cell is stored in the pseudo queue; Then determining whether the cell is stored in the pseudo queue and processing the cell stored in the pseudo queue according to the cell transmission order; And if the cell is not stored in the pseudo queue, processing a cell currently stored in the temporary buffer according to a check flag status of a cell in the pseudo queue, and a part of the total storage capacity for storing the cell. It is characterized by using a storage capacity (first storage place) variably.

The above objects, features, and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically illustrating a state in which the total storage capacity 20 is flexibly used in the average traffic rate control method to be implemented in the present invention. 21 and the state stored in the pseudo queue 22 according to the situation are shown.

At this time, the '↓' mark in the drawing indicates the number of cells 10 inputted during one service time, and the portions indicated by dots at the top and bottom of each storage location have a variable upper limit (a) and a fixed one line ( b), in the present invention, for the sake of simplicity, the storage capacity that can be stored in each of the storage places 21 and 22 will be 5 when the number of cells 10 is indicated. The portion 10 represented by the hatch (///) inside thereof represents a state in which the cells 10 are stacked in the first storage 21 according to the number of the input cells 10, and the reverse hatch is shown. (I) shows the state in which the input cells 10 are stacked in the pseudo queue 22.

As shown in the figure, there are three cells 10 input when the first window 23 is executed, and these cells 10 have a capacity that can be sufficiently accumulated in the first storage 21, and thus the first storage. Stored in place 21.

When the second window 24 is executed after the execution of the first window 23 is completed, the first storage 21 is completely emptied and starts to store the cells 10 input when the second window 24 is executed. do.

In this case, as shown in the drawing, the storage capacity of the first storage place 21 is increased than that of the first storage place 21 when the first window 23 is executed. When the input cells 10 are stored, it can be seen that an extra capacity remains after the storage. The remaining capacity is added to the first storage 21 when the second window 24 is executed. To make it variable.

Accordingly, when the second window 24 is executed, all the cells 10 inputted are seven, but since the storage capacity of the first storage 21 has already increased, all the cells are stored in the first storage 21 without any difficulty. Save it.

Then, when the third window 25 is executed, at this time, since the storage capacity increased during the execution of the second window 24 is used up, the corresponding first storage place 21 when the third window 25 is executed. ) Again has a default storage capacity, and can not store the cell 10 except the basic capacity.

Therefore, since the input cells 10 are currently nine, these cells 10 are not accumulated in the first storage 21, and only five of them are stored. The remaining four are stored in the pseudo queue 22.

In this state, when the execution of the third window 25 is completed and the storage capacity of the first storage place 21 when the fourth window 26 is executed, the pseudo queue 25 is executed in the execution of the third window 25. Since the storage capacity equal to the used capacity decreases, the storage capacity of the first storage location 21 at the time of executing the fourth window 26 is reduced.

Accordingly, the storage capacity of the first storage location 21 when the fourth window 26 is executed becomes a capacity that only one cell 10 can be stored. At this time, since the input cell 10 is also one, one is stored. do.

Summarizing the above-described bar once again, it can be seen that the upper limit of the first storage place 21 is variably increased / decreased depending on the state in which the storage capacity is used at the service time of the front end thereof. Since all the spare capacity that has not been used in the storage 21 is used, the average traffic transmission rate can be more efficiently controlled.

In addition, the storage means used to control the average traffic transmission is used a separate temporary buffer in addition to the entire storage location, which is used to store all the cells first input.

The detailed algorithm of the present invention for enabling the above-described operation will be described in detail with reference to the flowchart of FIG. 2.

When a window is started and the storage operation of cells input during the service time serviced in this window is determined, it is determined whether the currently running service is the end of the window. A first step (S1) of calculating a value and initializing a check flag for storing a cell in a pseudo queue while increasing a service time if the window is not at the end of the window; A second step S2 of determining whether or not a cell is stored in the pseudo-queue and processing the cell starting from the cell stored in the pseudo-queue according to the cell transfer order; If a cell is not stored in the pseudo queue, a third step (S3) of processing a cell currently stored in the temporary buffer according to a state of whether or not a cell is stored in the pseudo queue is checked.

The calculating of the upper limit value of the first storage location in the first step (S1) is an operation for varying the storage capacity of the first storage location of the total storage space in the next service, the first storage at the average number of allowable cells Subtract the counter value counting the number of cells stored in the location and store it in a variable called Margin (Margin = average number of cells allowed-counter value), then add the result of the operation to the limit of the allowable cell, and then Replace with limit of allowable cell again (limit of allowable cell = limit of allowable cell + margin). After the counter value is initialized to 0, the following steps of the present invention are sequentially performed.

In addition, the reason for initializing (off) the cell storage presence / absence check flag in the pseudo queue in the first step S1 is to prevent two or more cells from passing during a service time. If it indicates that it is serving the currently input cell, it prevents other cells from passing through.

The second step (S2) of processing a cell according to whether a cell is stored in the pseudo queue determines whether a cell stored in the pseudo queue exists, and if the cell does not exist, processing the cell stored in a temporary buffer. Performing a third step S3 (S2-1); If the cell is stored in the pseudo queue as a result of the determination in step S2-1, whether the value of the counter that counts the number of cells input to the second storage location is smaller than the limit value of the allowable cell (counter value allowable cell). (S2-2) determining the threshold value of the threshold value and performing the third step (S3) of processing the cell stored in the temporary buffer if it is larger than the threshold value of the allowed cell; And in step S2-2, if the value is smaller than the limit value of the allowable cell, the counter is increased by one, and the check flag on / off of cell storage in the pseudo queue is turned on (S2-3).

At this time, in order to increase the counter value by 1 in step S2-3, in order to output the cells stored in the pseudo queue to the outside, the cells are output from the pseudo queue and stored in the first storage location, and then the first storage is performed. This is because the output is through the place.

In other words, a pseudo queue cannot directly output a cell to the outside.

The flag is turned on to indicate that a cell is currently stored in the pseudo queue, and to prevent processing of a cell input into a temporary buffer without first processing a cell stored in the pseudo queue.

Lastly, the third step (S3) of processing a cell currently stored in the temporary buffer according to the state of whether or not a cell is stored in the pseudo queue is determined by first determining whether the cell currently stored in the temporary buffer exists. Otherwise, jumping to the first step S1 to perform a next service to determine whether the window is the last step (S3-1); If there is a cell stored as a result of the determination in step S3-1, determining whether a check flag state of whether a cell is stored in a pseudo queue is present or not (S3-2); In the step S3-2, if the flag is turned on, it is determined whether or not the storage capacity remains in the pseudo queue. If the storage capacity remains, the cells stored in the temporary buffer are re-stored in the pseudo queue. Jumping to the first step S1, if no storage capacity remains, discarding the cell and then jumping to the first step S1 (S3-3); If the determination result flag in the step (S3-2) is off, it is determined whether the value of the counter counting the number of times the cell has been input to the first storage location is smaller than the limit value of the allowable cell (the limit value of the counter value allowable cell). When the value of the counter is smaller than the limit value of the allowable cell, the counter is incremented by one, and then repeating the first step S1 (S3-4); And if the value of the counter is greater than the limit value of the allowable cell, it is determined whether there is an extra storage space for storing the cell in the pseudo-queue. And storing the cell in the pseudo-queue and jumping to the first step S1, and if the storage space does not remain, discarding the cell and jumping to the first step S1 (S3-5).

Summarizing the above process, the upper limit value of the first storage location is variably adjusted according to the number of allowable cells in the previous step. When more cells than the average are passed in the window of the previous step, the margin is calculated as a negative value. Therefore, the number of allowable cells in this window is smaller than the number of allowable cells in the previous window. On the contrary, when fewer cells are passed than the average in the previous window, the margin is calculated as a positive value. Is larger than the number of allowable cells in the previous window.

Therefore, in conclusion, it is appropriate to cope with each service having various data rates.

As described in detail above, the present invention allows the upper limit value of the first storage location to be changed according to the cell storage capacity of the previous stage in the entire storage capacity having the same capacity as before, and thus, each service having various data rates. By flexibly dealing with these, there is an effect of reducing the discarded cells.

In addition, a preferred embodiment of the present invention is disclosed for the purpose of illustration, those skilled in the art will be able to make various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications and modifications belong to the following claims You will have to look.

Claims (6)

In the asynchronous transmission mode (ATM) network, the average traffic control method, determining whether the current running service is the end of the window, calculates the upper limit value of the first storage location if the end of the window, and if not the end of the window Increasing time and initializing a cell storage presence / absence check flag in the pseudo queue; Then determining whether the cell is stored in the pseudo queue and processing the cell stored in the pseudo queue in order of cell transfer; And if the cell is not stored in the pseudo queue, processing a cell currently stored in the temporary buffer according to a check flag status of a cell in the pseudo queue, and a part of the total storage capacity for storing the cell. An average traffic rate control method in an asynchronous transmission mode (ATM) network, characterized in that the storage capacity (first storage location) is used variably. The method of claim 1, wherein the calculating of the upper limit value of the first storage location comprises: storing the first storage location in the first storage location in order to vary the storage capacity of the first storage location among the total storage spaces in the next service. An asynchronous method characterized by subtracting a counter value counting the number of cells, adding the result value of the operation to the limit value of the allowable cell, replacing the result value with the limit value of the allowable cell, and then initializing the counter value to 0. A method for controlling average traffic rate in a transmission mode (ATM) network. The method of claim 1, wherein the initialization of a cell storage presence / absence check flag in the pseudo-queue indicates that the other cell is being serviced by turning off the flag to prevent the passage of two or more cells during one service time. A method for controlling the average traffic rate in an asynchronous transmission mode (ATM) network, characterized in that it does not pass. The method of claim 1, wherein the processing of the cell according to whether or not the cell is stored in the pseudo-queue includes determining whether a cell stored in the pseudo-que exists, and processing the cell stored in the temporary buffer if the cell does not exist. Performing the process; If the cell is stored in the pseudo queue as a result of the determination in step S2-1, it is determined whether or not the value of the counter that counts the number of cells input to the first storage location is smaller than the limit value of the allowable cell. Performing the process of processing a cell stored in a temporary buffer if it is greater than a cell limit; And if the value is less than the limit value of the allowable cell, operating the counter and increasing the value by 1, and changing the state of whether or not the cell is stored in the pseudo queue is changed in the asynchronous transmission mode (ATM) network. Average traffic rate control method. The method according to claim 4, wherein the whether or not the cell storage check flag in the pseudo-queue is turned on the current pseudo to turn on the flag in order to prevent the first processing of the cell input to the temporary buffer without processing the cells stored in the pseudo-queue A method for controlling average traffic rate in an asynchronous transmission mode (ATM) network, characterized in that to indicate that the cell is stored in the queue. The method of claim 1, wherein the processing of the cell stored in the temporary buffer according to the state of whether the cell is stored or not in the pseudo queue is determined by determining whether or not the cell currently stored in the temporary buffer exists. Repeating the process of determining whether the window is the last to perform a service; If there is a cell stored as a result of the determination in the above step, determining whether or not a check flag state of a cell stored in a current pseudo queue is on; In the above step, if the flag is turned on, it is determined whether or not storage capacity remains in the pseudo-queue. If the storage capacity remains, the cell stored in the temporary buffer is re-stored in the pseudo-queue and then the end of the window is determined. Repeating the judging process, and if the storage capacity does not remain, discarding the cell and then judging whether it is the end of the window; In the above step, if the flag is off, it is determined whether the value of the counter counting the number of times the cell is input to the first storage location is smaller than the limit value of the allowable cell. Incrementing the counter by one and then repeating the process of determining whether the window is the last; And if the value of the counter is greater than the limit value of the allowable cell, it is determined whether there is an extra storage space for storing the cell in the pseudo queue, and if there is storage space, the cell existing in the temporary buffer is stored in the pseudo queue. And repeating the process of determining whether the end of the window is repeated after storing the data, and if the storage space does not remain, discarding the cell and repeating the process of determining the end of the window. Average traffic rate control method in an asynchronous transmission mode (ATM) network.