The design of a fuzzy logic controller of an ATM switch and its simulation

Available Bit Rate (ABR) streams are carried whenever bandwidth is available to do so. When transporting MPEG streams over ATM networks, the link utilization cannot be brought close to 100% no matter how efficient the connection control admission scheme is, but can be improved by ABR traffic. Due to the unpredictable fluctuations and burstiness of the MPEG streams, it is difficult to accurately control the ABR flow rate. A traffic control mechanism based on fuzzy logic is therefore required to effectively transport ABR traffic so that network operators can use most of the unused bandwidth. In this paper, we present the design of an optimized Fuzzy Logic Controller (FLC) of an ATM switch for the rate control of an ABR stream. Unlike the previous work where synthetic data and trial and error were used for tuning an FLC, the merits of our method are that we used simulations and real MPEG data to generate the input-output data for the optimal design of the FLC, and that our technique enables the output of the FLC to be symmetrical.