FPCF Input-Queued Packet Switch for Variable-Size Packets

The existing forward planning conflict-free (FPCF) packet switches are designed for fixed-size packets and synchronous operation mode. In this paper an asynchronous FPCF packet switch for variable-size packets is proposed. The key problem of efficient packet insertion procedure was solved by introduction of a so-called quasi-synchronous record array arrangement. A performance evaluation based on simulations is provided in terms of throughput, delay and loss probability. The limited maximum switch throughput is a deficiency of the presented asynchronous FPCF packet switch. In most cases, utilization of over 90% can be achieved by using multiple traffic flows, while preserving proper packet order. Maximum packet delays are comparable to those produced by output-queued packet switches. By comparing FPCF and virtual-output-queued packet switches a conclusion is drawn that FPCF switch produces both, lower maximum packet delays and lower packet delay variations.