A Practical Matching of Output Queueing with a 3D-VOQ Switch

D.-J. Tsaur, C.-H. Yu, H.-K. Cheng, C.-C. Wu, and W. Lin (Taiwan)


Communication system, packet switching, QoS guarantees, speedup, Combine input output queueing.


In this paper, we show that the three-dimension virtual output queue (3D-VOQ) can emulate an output-queued switch only operating at the line speed. This 3D-VOQ switch, which provides an exact emulation of an output queued switch with a broad class of service scheduling algorithms, requires no speedup regardless of its incoming traffic pattern and switch size. First, an N×N 3D-VOQ switch was proposed. In this contention-free architecture, the head-of-line problems are eliminated with a few virtual output queues (VOQ) from input sides and output sides were arranged using sufficient separate queues. Next, we propose a Small Time-to-leave Cell First (STCF) algorithm to produce a stable many-to-many assignment. It is also demonstrated and illustrated that the proposed 3D-VOQ switch is capable of being used to mimic an exact OQ switch. Finally, analysis and simulation are employed to verify the performance of 3D VOQ and to meet high/low QoS requirements.

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