Abstract: Data cells arriving in a switching unit are routed to virtual output queues. Load balancing method selects switching elements based on a dynamic utilization tracked by request virtual output queues that store switching requests from the virtual output queues.

Abstract: Method and apparatus for receiving bus signals from a first computer module, converting those bus signals into a first point-to-point link and directing the first point-to-point link to a bus emulator. The bus emulator propagates data transfer cycles arriving by the first point-to-point link to a second point-to-point link. The second point-to-point link carries data transfer cycles to a second computer module. The second point-to-point link is converted back into bus signals that interface with the second computer module.

Abstract: A preferred embodiment of a symmetric multiprocessor system includes a switched fabric (switch matrix) for data transfers that provides multiple concurrent buses that enable greatly increased bandwidth between processors and shared memory. A high-speed point-to-point Channel couples command initiators and memory with the switch matrix and with I/O subsystems. Each end of a channel is connected to a Channel Interface Block (CIB). The CIB presents a logical interface to the Channel, providing a communication path to and from a CIB in another IC. CIB logic presents a similar interface between the CIB and the core-logic and between the CIB and the Channel transceivers. A channel transport protocol is is implemented in the CIB to reliably transfer data from one chip to another in the face of errors and limited buffering.

Abstract: A preferred embodiment of a symmetric multiprocessor system includes a switched fabric (switch matrix) for data transfers that provides multiple concurrent buses that enable greatly increased bandwidth between processors and shared memory. A Transaction Controller, Transaction Bus, and Transaction Status Bus are used for serialization, centralized cache control, and highly pipelined address transfers. The shared Transaction Controller serializes transaction requests from Initiator devices that can include CPU/Cache modules and Peripheral Bus modules. The Transaction Bus of an illustrative embodiment is implemented using segmented buses, distributed muxes, point-to-point wiring, and supports transaction processing at a rate of one transaction per clock cycle.

Abstract: Communication circuitry is comprised of processing circuitry, parallel channels, and crossbar integrated circuits. The processing circuitry exchanges the communications between communication links and the parallel channels. The parallel channels transfer the communications in parallel with a clock signal. The crossbar integrated circuits receive the communications and the clock signal over the parallel channels, switch the communications based on the clock signal, and transfer the switched communications to the parallel channels.

Abstract: A preferred embodiment of a symmetric multiprocessor system includes a switched fabric (switch matrix) for data transfers that provides multiple concurrent buses that enable greatly increased bandwidth between processors and shared memory. A Transaction Controller, Transaction Bus, and Transaction Status Bus are used for serialization, centralized cache control, and highly pipelined address transfers. The shared Transaction Controller serializes transaction requests from Initiator devices that can include CPU/Cache modules and Peripheral Bus modules. The Transaction Bus of an illustrative embodiment is implemented using segmented buses, distributed muxes, point-to-point wiring, and supports transaction processing at a rate of one transaction per clock cycle.