Exhaustive limited service round robin matching algorithm for buffered crossbar switches

In this paper a high performance and simple scheduling algorithm for combined input-crosspoint crossbar switches, called exhaustive round-robin with limited service (ELRR) is presented and analyzed. We propose using of this scheduling system for arbitration at inputs and crosspoints. If the virtual output queue (crosspoint buffer) becomes empty, the input (crosspoint) arbiter updates its pointer to the next location in a fixed order. Otherwise, the pointer remains at the current virtual output queue (crosspoint buffer). To avoid unfairness under some extremely unbalanced traffic pattern limited service matching is presented. It is shown that this new solution offers high performance for several admissible traffic patterns using only one-cell crosspoint buffers.