Two Real-Time Flow Controls in Wormhole Networks

Abstract

In this paper, we study wormhole routed networks and envision their suitability for real-time traffic in a priority-driven paradigm. A traditional blocking flow control in wormhole routing may lead to a priority inversion in the sense that high priority packets are blocked by low priority packets for unlimited time. The priority inversion causes the frequent deadline missing even at a low network load. This paper therefore proposes two preemptive flow control policies where high priority packets can preempt network resources held by low priority packets. As a result, the proposed flow controls can resolve the priority inversion. Our simulations show that preemptive flow controls significantly reduce deadline miss ratios for various real-time traffic configurations.