An Analytical Method for the Analysis and Design of AFDX Networks

Date

2023-6

Author

Ayhan, Zeynep

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The development of AFDX (Avionics Full-Duplex Switched Ethernet) arose from the inability of traditional solutions to meet the modern real-time communication requirements of avionics. AFDX is a standardized solution for multiplexing large amounts of flows in the form of virtual links (VLs) over a full duplex, switched Ethernet network. AFDX resolves the nondeterminism problem of vintage Ethernet by flow-based traffic shaping and buffer management at the end systems and switches. Nevertheless, timing analysis is required to guarantee deterministic end-to-end latencies of critical data transmission for the reliability of an AFDX network. This study develops a novel method for the computation of tight upper bounds for the worst-case end-to-end delays for frames of each VL on AFDX networks by determining the highly variable queuing delays associated with each output port along the flow’s path. The worst-case queuing delay at switches is computed based on a careful analysis of the longest transmission intervals from incoming links contributing to the longest uninterrupted transmission on the outgoing link. In addition, the latest start of the transmission on the outgoing link is determined to minimize the transmission duration before the arrival of the frame of interest. After determining the maximum queuing delays on each port, the overall worst-case end-to-end latency per VL is obtained through the addition of related delay components. Moreover, the proposed method is validated through specifically designed experiments on a simple example network and on a realistic network. The method’s applicability extends beyond AFDX and can be employed in any switched Ethernet network with non-preemptive and rate-constrained traffic, as demonstrated and verified in this study.

Subject Keywords

AFDX, Avionics, Ethernet, Real-Time Network, Worst-Case Delay

URI

https://hdl.handle.net/11511/104510

Collections

Graduate School of Natural and Applied Sciences, Thesis