The asynchronous transfer mode (ATM) provides efficient switching capability for various kinds of communication services. To guarantee the minimum quality of services in the ATM networks, the bandwidth allocation setup procedure between the network nodes and users is very important. However, most of call admission control (CAC) methods which have been proposed so far are not fully appropriate to apply to real environments in terms of the complexity of the hardware implementation or the accuracy of assumptions about the cell-arrival processes. In addition, the success of broad bandwidth applications in the future multimedia environments will largely depend on the degree to which the efficiency in communication systems can be achieved, so that establishing high-speed CAC schemes in the ATM networks is an indispensable subject. This paper proposes a new cell-loss rate estimation method for the real time CAC in ATM networks. A neural network model using the Kalman filter algorithm was employed to improve the error minimizing process for the cell-loss estimation problem. In the process of optimizing the three-layer perceptron, the average, the variance, and the 3rd central moment of the number of cell arrivals were calculated, and cell-loss rate date based on the non-parametric method were adopted for outputs of the neural network. Evaluation results concerned with the convergence using the sum of square errors of outputs were also discussed in this paper. Using this algorithm, ATM cell-loss rates can be easily derived from the average and peak of cells rates coming from users. Results for the cell-loss estimation process suggest that the proposed method will be useful for high-speed ATM CAC in multimedia traffic environments.

The connection admission control is one of preventive traffic control in ATM networks. The one objective of connection admission control is to keep the network load moderate so as to achieve a performance objective associated with quality of services (QOS). Because the cell loss rate is more sensitive to offered load than the average queuing delay in ATM networks, QOS requirement associated with cell loss rate is considered. The connection admission control acts as one of the major roles in traffic control. The job of connection admission control is to make an acceptance decision for connection set-up request to control the network load. This paper proposed and evaluated a connection admission control method. The proposed method is suitable for real time operation even in large diversity of connection types, because the amount of calculation for connection admission control is reduced remarkably compared to conventional algorithms. Moreover, the amount of calculation for the algorithm does not increase even when the number of connection types increases. The proposed method uses probability function for the number of cells transferred from multiplexed connections and uses recursive equations in estimating cell loss rate.