KR100374351B1 - Dynamic call accepting control method in atm network on basis of real time traffic measurement - Google Patents

Abstract

PURPOSE: A dynamic call accepting control method in an ATM(Asynchronous Transfer Mode) network on the basis of real time traffic measurement is provided to effectively use resources of an ATM network and control congestion. CONSTITUTION: When a user requests a call connection of a maximum transfer rate 'A'(100), it is checked whether a maximum cell loss rate is greater than a pre-set limit value(102). If the maximum cell loss rate is greater, it is checked whether a band as much as 'A' can be allocated from a class(104). If the band can be allocated, band between classes is re-allocated(106) and a call is accepted(108). If the band as much as 'A' does not remain in the class, it is checked whether the insufficient band can be allocated from a different class(116). If the insufficient band can be allocated from a different class, the band between classes is re-allocated(106) and a call is accepted. If the insufficient band can not be allocated from the different class, a call is rejected(118).

Description

Dynamic Lock Control in Asynchronous Transmission Mode Networks Based on Real-Time Traffic Measurements

The present invention relates to a data communication system, and more particularly, to a method for controlling call admission that is used for efficient network resource management on B-ISDN and for coordinating intra-network traffic.

Due to the characteristics of the network itself, high speed data transmission, error recovery caused by retransmission causes enormous loss in network operation efficiency, and the occurrence of error is fatal when considering multimedia services provided in the network. Therefore, call access control has emerged as a preventative traffic method.

Conventional rockock control includes arithmetic method using equivalent bandwidth, mathematical model of output queue, and probabilistic calculation method based on traffic measurement. However, they do not provide QOS (Quality Of Service) method. In terms of efficient use, its performance is poor.

First, a method using an equivalent band is a method of calculating a bandwidth required by calls connected to an existing network and a call requesting connection and determining whether the call is connected using the same. However, the method of obtaining the equivalent band by the mathematical model has a limitation in maintaining the QOS of each call continuously. In addition, calculating the equivalent band generally requires a large amount of calculation, which is difficult to process in real time.

Next, the method of modeling the output queue is a method of determining whether to accept a call by predicting and expressing the nature of the traffic and then predicting the cell loss rate in the output queue based on this. However, the method of predicting cell loss using a mathematical model of the output buffer is difficult to determine whether to accept a call connection in real time and because it uses a probabilistic model for each traffic source, it does not provide various QOS. In addition, since the traffic parameters presented by the users, which are highly dependent on this method, have a considerable error in describing the actual traffic, the prediction of cell loss is largely used in terms of QOS guarantee for loss. Can't.

After all, the problem with the existing technology is due to the fact that it is impossible to accurately predict the traffic in the network.

Accordingly, an object of the present invention is to provide a dynamic rock lock control method that balances two functions of maintaining cell loss and efficient use of network resources according to the QOS of a service required by a user.

In accordance with the above object, the present invention, by directly measuring the traffic in the network to obtain the traffic amount and cell loss, and then used for the control of the lake rock using the excellent performance in terms of efficient use of network resources and QOS guarantee according to the type of service Headed to have.

1 is a view showing a structure for measuring real-time traffic in accordance with the present invention,

2 shows the shape of an output queue in accordance with the present invention;

3 is a diagram illustrating an algorithm for controlling call admission using a maximum transmission rate suggested by a user and a maximum equivalent cell loss rate obtained from a traffic measurement.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same elements in the figures are represented by the same numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

Operation lock control method based on the real-time traffic measurement according to the present invention is as follows. Such a method of controlling the operation lock is schematically illustrated in FIG. First, when a call connection request is received from a user, the rockacy control algorithm according to the present invention uses the maximum transmission rate presented by the user, the maximum traffic amount (ie, the maximum equivalent bandwidth), and the maximum cell loss. Determine. Traffic volume (bandwidth) and cell loss rate are measured over N time intervals, and the value shifts and continues to update. The size W of each time interval is set smaller than the minimum burst interval processed in the class among the traffic flowing into the network to prevent the loss of QOS due to the averaging effect.

Meanwhile, in the present invention, the length of the output queue is limited according to the type of service (QOS class) in order to satisfy the delay condition during QOS. The length of the queue should be less than the maximum allowable delay period x output link capacity / cell size. Each traffic, such as delay sensitive and loss sensitive, uses output queues of different lengths, depending on its QOS.

The form of such an output queue is shown in FIG. Referring to FIG. 2, the class switch 20 sends traffic to the classes 22-1 and 22-N of the output queue assigned to the QOS according to the QOS class of the input traffic. The server 24 first transmits cells in each queue in proportion to the bandwidth allocated to each queue, and processes cells of different classes if there are no cells to process at that time.

Call admission control is performed by the algorithm of FIG. 3, which is presented below using the maximum transmission rate presented by the user, the maximum equivalent bandwidth obtained from the traffic measurement, and the maximum cell loss rate. The algorithm of FIG. 3 performs independently for each class.

Referring to FIG. 3, first, in step 100, when a user requests a call connection of the maximum transmission rate A, in step 102, it is determined whether the maximum cell loss rate is greater or less than a preset limit value. If the maximum cell loss rate is greater than the threshold, the process proceeds to step 104 and determines whether or not as many bands as A can be allocated from the class. If so, proceed to step 106 to reallocate the inter-class band, and accept the call in step 108. However, if the bandwidth of A can not be allocated from the class in step 104, the process proceeds to step 110 to reject the call.

On the other hand, in step 102, it is determined whether the maximum cell loss rate is less than the preset limit in step 112, and it is determined whether as many bands as A remain in the class. However, in step 112, if there are no bands remaining in the class, the process proceeds to step 116 to determine whether an insufficient band can be allocated from another class, and then the process proceeds to step 106 to reallocate the band between classes and the call in step 108. Control acceptance. However, if it is unable to allocate the insufficient band from another class in step 116, the process proceeds to step 118 to reject the call.

The algorithm shown in FIG. 3 performs independently for each class based on the proposed queue structure and service principle. Of course, it should be noted that the values of N and W used for traffic measurement in each class are different from class to class.

In the above description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

As described above, the present invention has the advantage of independently processing traffic requiring various QOS, guaranteeing the required QOS according to each class, and efficiently using network resources.

Claims (3)

In the rock lock control method in the asynchronous transmission mode network, The size W of N time intervals is set to be smaller than the minimum burst duration processed in the corresponding class among the traffic flowing into the network, and the maximum bandwidth of the current state is measured by measuring the traffic flowing into the network in real time over the N time intervals. Calculating a quantity and a maximum cell loss rate; A second process of allocating the length of the output queue to the class of the output queue so that the length of the output queue is smaller than the maximum allowable delay period x output link capacity / cell size according to the quality of service to satisfy the delay condition of the quality of service; A third step of comparing and determining the calculated maximum cell loss rate with a preset threshold value when a call connection request is connected from a user; A fourth step of determining whether a band for requesting a call connection can be allocated from a predetermined class when the maximum cell loss rate is greater than the threshold value; A fifth step of reallocating an inter-class band and accepting a call if the class can be allocated to the band for the call connection request; A sixth process of rejecting a call if the band for the call connection request cannot be allocated from the class; A seventh process of determining whether a band remaining at the call connection request remains in a predetermined class when the maximum cell loss rate is less than the threshold value; An eighth step of accepting a call if the band at the time of the call connection request remains in a predetermined class; A ninth step of judging whether an insufficient band can be allocated from another class if the band at the time of the call connection request does not remain in a predetermined class; A tenth step of reallocating an inter-class band and accepting a call if the insufficient band can be allocated in the ninth step; And the eleventh process of rejecting a call if the insufficient band cannot be allocated in the ninth process. The method of claim 1, wherein the class independently performs admission control of a call connection according to each quality of service. The method of claim 1, wherein, in the class, the size W and the number N of time periods used for traffic measurement are different for each corresponding class.