Performance analysis of a robust scheduling algorithm for scalable input-queued switches

In this paper a high-performance, robust and scalable scheduling algorithm for input-queued switches, called distributed sequential allocation (DISA), is presented and analyzed. Contrary to pointer-based arbitration schemes, the algorithm proposed is based on a synchronized channel reservation cycle whereby each input selects a designated output, considering both its local requests as well as global channel availability information. The distinctiveness of the algorithm is in its ability to offer high-performance when multiple cells are transmitted within each switching intervals. The subsequent relaxed switching-time requirement allows for the utilization of commercially available crosspoint switches, yielding a pragmatic and scalable solution for high port-density switching platforms. The efficiency of the algorithms and its robustness is established through analysis and computer simulations addressing diverse traffic scenarios.