Forward end-to-end delay analysis extension for FP/FIFO policy in AFDX networks

Abstract

Avionics Full DupleX Switched Ethernet (AFDX) switches, used in major civilian aircraft, have flow differentiation capability via multiple levels of Fixed Priority (FP) traffic classes. Inside a class, frames are handled in a First In First Out (FIFO) manner. End-to-end (ETE) delays, in such a network, have to be determined and an upper-bound is mandatory for certification purpose. Several methods, such as Network Calculus (NC) and Trajectory Approach (TA), can compute worst-case ETE delays in both FIFO and FP/FIFO contexts. The Forward end-to-end delay Analysis (FA) has been formerly developed for FIFO scheduling, and in this paper, we extend it to cover also FP/FIFO. We apply to the approach an optimization related to flow serialization, which has already proven to be effective for other methods and other servicing strategies. Finally, we apply FA on a sample configuration and compare the results to the two aforementioned approaches (TA and NC).