A High-Speed Scheduling Algorithm for Combined Input-Crosspoint-Queued (CICQ) Switches

With the development of ASIC technology, buffered crossbar is very popular for building switch architecture nowadays. This makes the combined input-crosspoint-queued (CICQ) switch a more attractive solution than the traditional input-queued (IQ) switch because of the simplicity of the CICQ switch scheduling. Recently, many distributed scheduling policies have been proposed based on this architecture. However, the existing schemes still require quite a bit of hardware or timing complexity to obtain good performance. In this paper, we propose an earliest state-reversed buffer first (ESRBF) scheme, and prove that it achieves 100% throughput for any admissible traffic that satisfies the strong law of large numbers (SLLN). The ESRBF algorithm is based only on the state information of the crosspoint buffer and has a time complexity of O(log N). The simulation results also verify a good performance of the ESRBF scheme