Performance analysis of ATM switches using priority schemes

B-ISDN is expected to support diverse applications ranging from low bit rate communications between terminals and host computers to the broadcasting high resolution TV signals. One of the most promising approaches for the B-ISDN is the asynchronous transfer mode (ATM) where all information (such as voice, data, image and video) is divided into fixed length data format, called cells, and these cells are asynchronously transmitted through the network. ATM networks must provide multimedia services with diversified traffic flow characteristics and quality requirements, thus priorities are given to different classes of services. To achieve the requirement of each class, a suitable priority management scheme is needed. The authors propose a priority management scheme to achieve the delay requirement and the packet loss rate requirement of each class. The analytical process uses a Markov chain to analyse the average delay time and the packet loss rate of each class. A computing algorithm is proposed to generate the states of the Markov chain and the corresponding transition probability matrix automatically. The results indicate that the proposed priority management scheme provides a real-time service for the time constrained class, and the required buffer size in the switches can be greatly reduced when the control parameter is appropriately chosen