Performance evaluation of a parallel-poll virtual output queued switch with two priority levels

Development of high performance switches is of paramount importance in high bandwidth connection networks. Input buffered switches with virtual output queues (VOQ) are most impressive because the access rate of crossbar and buffer memory is not higher than the line rate of the connected link. To support various types of traffic with different quality of service (QoS), the packet scheduling algorithms, which solve the contentions in the transfer of data units from an input link to the appropriate output link, must provide different guarantee for different types of traffic. In this paper, based on the parallel-poll VOQ (PP-VOQ) architecture, we propose a simple novel cell scheduling algorithm with two priority levels. We show by simulation that, in the case of cell-based switches, this priority mechanism provide performance advantages over prioritized iSLIP and such an input-queued architecture can provide guaranteed rate, bounded delay, and jitter-restriction for both two priority levels of traffic.