ANALYSIS OF CONGESTION IN SMALL P. A. B. X. 's.

The methods commonly used to dimension various traffic carrying circuit groups in small automatic switching systems, such as P. A. B. X. 's, are based on very simplified traffic distribution models, which neglect the correlation of traffics in local, incoming and outgoing circuit groups due to the limited common pool of traffic sources that these circuits serve. In this paper a more realistic mathematical model is postulated for such systems, embracing all traffic components and considering their interaction. To derive the necessary congestion probabilities a shortcut analytical technique is employed, which gives surprisingly accurate results in practical cases.