Bandwidth assignment control in ATM system

ATM (asynchronous transfer mode) system transfers and switches the information from various media such as voice, data, and video in a unified way. Since media with severe requirements for high-speed transfer or real-time processing must be handled, there is no flow control function during communication. As a result, a certain bandwidth must be assigned to each call to ensure service quality. This paper considers first the case where the same bandwidth is shared by several classes with different service requirements. The “flexible processing” system is proposed as a priority processing method where the qualities of other classes are not deteriorated even if there arises an unexpected traffic flow of a particular class. For bandwidth assignment to each call in the same class, the “volume declaration” method is proposed, wherein the user declares the maximum information content (= volume) that can be transferred in the specified time, in addition to the maximum information transfer rate. It is shown that the service quality of the call can be insured by this method. Then we examine the case in which physically distributed bandwidths are utilized by more than one service quality class, and it is shown that the results of past studies on the multirate circuit switching can be applied, by assuming the forementioned volume declaration method.