Abstract: A computer-system bus switch architecture is presented that has high throughput and low latency. The architecture provides a multi-port PCI bus switch that includes a primary port controller, a crossbar switch, and a plurality of secondary port controllers. The primary port controller couples to a main system bus to which, for example, a system controller is coupled, and the secondary port controllers are each coupled to a local bus to which a plurality of peripheral devices are coupled. The crossbar switch selectively routes traffic from any port controller to any other port controller.