Fixed-length switching vs. variable-length switching in input-queued IP switches

Chengchen Hu, Xuefei Chen, Wenjie Li, Bin Liu
2004 IEEE International Workshop on IP Operations and Management  
Many large-scale, high speed routers adopt inputqueued switches with virtual output queuing (VOQ) for preventing head of line (HOL) blocking. Switching based on cellby-cell scheduling algorithms (fixed-length switching) have been widely studied for years, while a new idea of transferring IP packet based on a packet-by-packet scheduling algorithm (variable-length switching) has been proposed recently. These two switching modes differ largely in performance and implementation complexity. This
more » ... r establishes experiments at the aim of evaluating one design issue: whether it should be fixed-length switching or variable-length switching. We investigate various performance measures of interest: bandwidth utilization, packet loss, segmentation and reassembling overhead, as well as average packet latency. The focus of the paper is on identifying key parameters that influence the outcome of this comparison, and on quantifying the potential benefits of each switching mode. Keywords-input queued switch, fixed-length switching, variable-length switching I.
doi:10.1109/ipom.2004.1547602 fatcat:7bqk3yhr2zhwdeid3k4vxkde5a