The buffer size assignment of AFDX based on network calculus

AFDX (Avionics Full Duplex Switched Ethernet) developed for the Airbus A380 represents a major upgrade in both bandwidth and capability, but guaranteed kinds of service presents challenges to system designers. Scheduling new classes of traffics with different priorities on the same AFDX network is urgently to resolve. However, there´s no consideration of how buffer size influence the traffic performance with different priorities, since inappropriate buffer capacity will lead to frame missing or cannot satisfy requirement of real-time. Using network calculus, this paper provides an algorithm to determine the out-port optimal buffer size of End System (ES) with a static Priority Queuing (SPQ) on AFDX. Based on the results of this analysis, an example of ES shows that the algorithm is effective and practical. With this study, we provide a new method to configure buffer size and improve the physical configuration in the development stage.