Research And Implementation Of Deterministic Assessment In AFDX Network Based On Network Calculus

AFDX network is important network architecture of modern avionics system and the accuracy of deterministic assessment in AFDX network is the key to guarantee the safety of avionics system. Developed countries which using AFDX models must be adopting mathematical method to prove that network deterministic performance requirement is satisfied. At present, the main deterministic performance analysis methods have trajectory, model checking and network calculus. Network calculus can provide proofs of the exact boundary using simple method compare with the former two methods, this is especially important for the airworthiness certification of aviation electronic system. Due to the flow characteristics of avionics network has many random factors, the upper bound of delay and jitter with network calculus existing are generally large which resulting in although avionics network deterministic demand is satisfied, the allocation and configuration of resources are unreasonable, large waste. In order to obtain more accurate boundary value, we need to improve the traditional algorithm of network calculus, so as to improve the rational allocation of resources and improve the overall performance of aircraft system.This article finished the following works:Firstly, we analyzed and studied AFDX protocol and designed the network delay model according to transmission process and characteristics in AFDX network.Secondly, according to the requirement of deterministic and real-time in avionics system, we design a new network calculus algorithm based on multi-link grouping technology which can get tighter upper bound. At the same time we can obtain different end to end delay distribution with different information flow which provides more accurate basis for improving the performance of AFDX network system.Finally, we design and implement deterministic analysis plug-in in avionics system network based on EMF, and integrated in the IMA resource configuration tool IMACT which makes IMACT have ability to analysis deterministic of AFDX network system.