基于离散事件方法的AFDX建模与仿真

AFDX modeling and simulation based on discrete event method

采用了建模仿真的方法来分析航空电子全双工交换式以太网(AFDX,Avi-onics Full Duplex switched ethernet)协议.通过对AFDX协议的抽象,基于离散事件的建模方法,以基本的网络元素来抽象化网络中的端系统、交换机等设备,以离散事件来描述网络设备的行为,以此构建了AFDX网络模型,并依据模型实现了仿真.网络演算是一种理论计算AFDX最坏延迟界限的方法,将典型场景下仿真得到的结果与理论计算的结果进行比较,验证了模型.通过不同流量方案下仿真结果的对比,对AFDX进行了传输特性的分析.

For dimensioning avionics full duplex switched ethernet （AFDX） network, discrete event method was used. Devices in the network, such as end-system and switch, were modeled by the basic network elements. The communication behavior including VL control, message framing and switch forwarding etc. was described as discrete event. Different network elements were integrated by these events, and a model of the network was composed . Based on AFDX modeling, the simulation tool was developed with C ＋ ＋. Typical AFDX network topology was used to verify the model. The simulation was verified by comparison with the theo- ry calculus which is called network calculus. The result indicated that the modeling and simulation were reliable. Two simulation scenes with different network flow were used to analyzing the performance of AFDX. According to the simulation analysis, irregular flow generated by either end-system or switches was isolated by VL, so that it cannot take effect on the regular flow. The reliability of AFDX was verified.