Speedup Requirements for Output Queuing Emulation with a Parallel Packet Switch

This work analyzes whether a parallel packet switch (PPS) can emulate an output-queued (OQ) packet switch. The class of PPS is characterized by the deployment of parallel low-speed switches. Each lower speed packet switch operates at only a fraction of the input line rate R. This study develops and investigates a PPS which distributes cells to low-speed switches and uses outputs with push-in arbitrary-out (PIAO) queues. We present a novel Markov chain model that successfully exhibits these performance characteristics. The simulation results demonstrate that the developed Markov chain model is accurate for practical network loads. The major findings, obtained using the proposed model, are that: (1) the throughput and cell drop rates of a PPS can theoretically emulate those of an OQ packet switch as indicated in Eq. (49); and (2) the cell delay of a PPS can theoretically emulate that of an OQ packet switch as given by Eq. (51).