Mode Change Performance Analysis In AFDX Network

The increasing complexity of avionic system has prompted the requirements of throughput for data exchange. For ARINC429, its transmission speed is 100Kbps, has more and more difficult to meet the requirements of modern avionic system. Robustness of traditional industrial Ethernet has been proved after a large number of test and applications, and then AFDX has advantages of low cost, high speed and good scalability. However, when the transmit data in AFDX network is changing with the shift of the upper applications, there will be two different types of data exist at the same time. At the same time, the network's data traffic will be more busy than before, and the network packet loss may happen because of overloading under certain circumstances. In avionic system the phenomenon is forbidden, so it's significant to research the data work mode change.In this paper, we research on the data overload in network during the avionic system mode change, which is how to avoid package loss during the mode change.The main work and research results are summarized as follows:(1) Research on AFDX network nodes, End System and Switch have been modeled and then the model is analyzed.(2) In single switch, the network utilization is reduced by introducing the offset. Then the schedulability is analyzed.(3) Considering the end-to-end mode change transition time, the paper has analyzed the mode change transition time on single-hop and then multi-hop. The switch's transition time is obtained by working out the virtual links'worst case response time. (4) Using simulation software Truetime, the small AFDX network is set up. Combine the simulation results and theory, we conclude that offset could avoid mode change package loss.