Using camp-on to improve the performance of a Fibre Channel switch

A method is presented to improve the performance of the High-Performance Switching System (HPSS), a distributed switching system being designed for use in the campus-wide high-speed network prototype at the Lawrence Livermore National Laboratory. The HPSS uses protocols of the proposed ANSI Fibre Channel Standard (FCS). The system is based on a folded version of the Clos three-stage network, and its largest configuration has 4096 ports, each operating at 1.0625 Gb/s. The authors' approach improves the connection-setup time in the HPSS by queuing connection requests at destination ports, thus reducing the overhead associated with retries due to port-busy conditions. Results from a detailed simulation of the HPSS are presented to show the performance improvement for different traffic distributions and operating parameters.