Worst frame backlog estimation in an avionics full-duplex switched ethernet end-system

Abstract

With the increase of needs in capability, bandwidth and reliability of modern aeronautical equipment, Avionics Full-Duplex Switched Ethernet (AFDX) network has gained in popularity since its successful implementation in the Airbus A380. As AFDX networkis a deterministic network, frames have to reach the reception End-System (ES) within a limited amount of time: the upper bound of the end-to-end delay. Similarly, a frame arriving at the reception ES has to be processed within a deterministic amount of time to be available to host applications. The duration of frame storage in the ES reception buffer represents a significant part of delays. Optimizing the size of the ES reception buffer is then a critical issue, which requires a precise analysis of the Worst Frame Backlog (WFB). This is the issue that we address in this paper. We propose in particular a method to construct the longest sequence of back-to-back frames from a regular reception flow and a simulation tool to estimate the WFB that helps to determine the size of the ES reception buffer for any configuration.