Scheduling Mixed Unicast and Multicast Traffic with Variable-Size Packets in Input-Queued Switches

摘要

We consider scheduling mixed unicast and multicast traffic with variable-size packets in an input-queued switch. When variable-size packets arrive at a switch input port, they will be segmented into cells (fixed-size packets), sent across the switch fabric, and reassembled at outputs. A scheduling algorithm should focus on optimizing packet performance rather than cell performance. In this paper, packet-mode scheduling is adopted such that cells of the same packet are sent back-to-back in consecutive slots. For efficiency, an iterative scheduling algorithm called three-bit single-iteration (3BSI) is proposed to concurrently schedule both unicast and multicast traffic. To the best of our knowledge, 3BSI is the first packet-mode scheduling algorithm for handling mixed traffic with variable-size packets. Despite its simplicity, extensive simulation shows that 3BSI provides excellent delay-throughput performance.