Analysis and Optimization of a Banyan Based ATM Switch by Simulations

Asynchronous Transfer Mode (ATM) is proposed technology to create a broadband (high speed) packet switching network capable of transporting wide variety of services including voice, video and data in an integrated manner. The main concern in designing the switching fabrics used in this technology are speed, throughput, delay and variance of delay. We analyze the performance by simulations of ATM switch based on Banyan network in the uniform traffic condition. We compare the analytical results obtained from three-state model Yan and Jenq to the simulation results. Based on observation of simulation results, we propose non-blocking first stage (NBFS) to increase the throughput. In NBFS scheme, internal blocking in the switching element (SE) of the first stage is avoided. We extend the priority scheme proposed by Yan and Jenq by proposing enhanced priority {EP) scheme. In EP scheme, we give priority to the packet blocked greater number of times. The simulation results of the switch with combined NBFS and EP scheme, shows that the throughput increases, and the variance of delay decreases significantly. We simulated the single buffer Banyan network with mixed voice and data traffic. We propose double buffer switching element to increase the throughput, and decrease delay and variance of delay, of delay sensitive voice packet in mixed traffic condition. The simulation results of fully loaded 6-stage double buffer switching network, with 30% voice traffic, shows that the throughput increases by 23.7%, and delay and variance of delay of voice packets decrease by 12%.