FlowToss: Fast Wait-Free Scheduling of Deterministic Flows in Time Synchronized Networks

Randeep Bhatia, T. V. Lakshman, Mustafa F. Özkoç, Shivendra S. Panwar

Abstract: Motivated by important industrial automation use cases, such as closed loop motion control and autonomous mobile robots, we study wait-free scheduling of periodic flows with stringent delay and jitter requirements in time sensitive networks. The goal is to assign initial transmission time-slots to periodic flows so that network queuing delays are eliminated or are very small. We make use of Bézour's Identity to develop simple and fast scheduling algorithms for this NP-hard problem. Operating in an online mode, our algorithms can quickly allocate contention free start time-slots to new flows, without changing allocations of already scheduled flows. Our main results are greedy and random scheduling algorithms that can trade speed for solution quality. Our simulations on different network topologies show that these algorithms are computationally efficient and can easily schedule a large number of flows, thus meeting the requirements of many industrial automation use cases.