Scheduling Design and Analysis for End-to-End Heterogeneous Flows in an Avionics Network

Avionics Full DupleX (AFDX) Switched Ethernet technology provides a deterministic network with guaranteed service to support real-time data transmission in real-world avionics applications. The determinism provides a worst-case upper bound of end-to-end transmission delays of virtual links (VLs) that are often assumed to be homogeneous and have similar transmission requirements. However, performing the analysis of end-to-end delays of heterogeneous flows remains an open problem. This paper derives end-to-end delay bounds of transmitting heterogeneous flows, including avionics, multimedia (video & audio) and best-effort data flows, in an AFDX network that uses Deficit Round Robin (DRR) scheduling policy on switch output ports. To this end, we transform scaled multitype flows to a single representation of utilization, i.e., DRR quanta, to efficiently handle heterogeneous flows in a unified way and comprehensively study their end-to-end delays. We further compare the DRR-based scheduling policy with current avionics standards, i.e., FIFO and a static priority policy, in terms of transmission delays and fairness. Extensive experiments based on periodical and sporadic flows in an AFDX prototype show the efficacy and efficiency of our proposed schemes. To the best of our knowledge, this is the first work that analyzes end-to-end delays based on the DRR policy for heterogeneous flows in an AFDX network