Heuristic list scheduler for time triggered traffic in time sensitive networks

Abstract

Time Sensitive Networks (TSN) are a novel technology that combines the larger bandwidth capabilities of Ethernet with determinism and fault tolerance for safety relevant real time systems. TSN offers bounded latency for the time triggered (TT) communication by transmitting messages according to a global schedule. Most of the scheduling algorithms in this context provide the solution only from the perspective of scheduling constraints and do not consider the impacts of routing on the scheduling problem. Therefore, these algorithms are not capable to provide effective results in the domain of many real time systems. To address interdependence of routing and scheduling constraints, we introduce a heuristic list scheduler (HLS). Our approach generates valid schedules using joint routing and scheduling constraints in one step. Due to this approach, ability to find feasible schedules is dramatically increased in comparison to the schedulers with fixed routing. In addition, HLS supports multi-cast communication, distributed real time applications and inter-flow dependencies. Experimental results shows the significant increase in the schedulability because of the task and message scheduling combined with routing.

Communication Scheduling for Control Performance in TSN-Based Fog Computing Platforms

“…Arestova et al in [53] propose a hybrid genetic algorithm for the communication scheduling and network routing to find a near-optimal solution in a reasonable time, and also optimizing the bandwidth to let more less-critical traffic transmitted. A heuristic list scheduler for joint communication scheduling and network routing is proposed in [54], where multi-cast traffic and application distribution are allowed, and bandwidth is optimized. The same problem is addressed in [55] where a genetic algorithm is employed and in [23], where multiple traffic types are considered.…”

How to Optimize Joint Routing and Scheduling Models for TSN Using Integer Linear Programming

“…Therefore, several heuristics for speeding up schedule calculation have been proposed. For instance, Dürr et al proposed a heuristic based on tabu-search to reduce the runtime of the optimal TSN scheduling problem already mentioned above [4], Pop et al [16] propose a list scheduling-based heuristic for TSN scheduling in a Fog computing environment, and Pahlevan et al propose another list scheduling approach [13]. Furthermore, Pozo et al [17] combine incremental scheduling and decomposition to reduce the number of frames which need to be considered in a logical context at the same time by the SMT solver.…”

Research on routing and scheduling algorithms for the simultaneous transmission of diverse data streaming services on the industrial internet

“…The TT traffic transmitted in the link contains at least one TSN frame, and represents the transmission period of TT traffic; represents the load size of each TSN frame multiplied by the number of TSN frames in a transmission period; represents the maximum allowable end-to-end delay. According to the assumption of 31 , 32 , TT traffic is only kept in TSN within the processing time of the switch.…”

“…In the TSN switch port, we set up a queue for TT traffic scheduling. To ensure the determinism of scheduling, we set a guard band for TT traffic 31 , 32 . During and , the link is exclusive.…”

“…Condition 3 The TSN switch should not buffer TT traffic but only store and forward TT traffic 31 , 32 . The sending time of TT traffic to the next-hop node should be greater than or equal to the corresponding receiving time.…”