A priority forwarding scheme for real-time multistage interconnection networks

The authors propose a priority control scheme for packet switching multistage networks, called priority forwarding, which prevents priority inversion, a situation in which higher priority packets are blocked by lower priority packets. In an N*N omega network, the worst case delay of the priority forwarding scheme on the highest priority packet is O(log/sup 2/ N), while that for round-robin arbitration is O(N). Simulation results show that the priority forwarding scheme offers shorter delays for higher priority packets without throughput degradation and fits least-laxity-first control. The hardware implementation cost of this scheme is relatively small and requires no extra signal lines between routers. Consequently, this scheme offered predictability, scalability, and implementation eligibility.<
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