Network partition method of distributed IMA and its real-time performance evaluation

The concept of network partition is proposed for the architecture of distributed integrated modular avionics(IMA) which is based on temporal partition, spatial partition and bandwidth partition. Meanwhile, corresponding models are built including a network model, a message model, a traffic model and a scheduling model. The formulas for end-to-end (ETE) delays of mixed avionic message sets are derived with the help of network calculus theory. A typical network is then built, and theoretical computations are performed in order to compare the real-time performance of network partition with that of bandwidth partition. The computational results show that ETE delays of two hard real-time flows using network partition are reduced by 33.5% and 74.2% respectively as compared with that using bandwidth partition. On the other hand, delays of weakly hard real-time and weak real-time flows increase by about 30%. Finally, simulation using OPNET is done to verify the computational results. It demonstrates that the network partition method satisfies the requirements of distributed architecture of distributed IMA, and the demands of system mixed-criticality.