Improving the Worst-Case Delay Analysis of an AFDX Network Using an Optimized Trajectory Approach

Abstract

Avionics Full Duplex Switched Ethernet (AFDX) standardized as ARINC 664 is a major upgrade for avionics systems. The mandatory certification implies a worst-case delay analysis of all the flows transmitted on the AFDX network. Up to now, this analysis is done thanks to a tool based on a Network Calculus approach. The more recent Trajectory approach has been proposed for the computation of worst-case response time in distributed systems. This paper shows how the worst-case delay analysis of the AFDX can be improved using an optimized Trajectory approach. The Network Calculus and the Trajectory approaches are compared on a real avionics AFDX configuration. Moreover, an evaluation of an upper bound of the pessimism of each approach is proposed.

Formal timing analysis of CAN-to-Ethernet gateway strategies in automotive networks

“…Formal timing analysis using CPA for strict-priority Ethernet was presented in Rox and Ernst (2010). In Bauer et al (2010) the trajectory approach was applied to analyze Avionics Full Duplex Switched Ethernet (AFDX).…”

The Trajectory approach for AFDX FIFO networks revisited and corrected

“…However, for frames transmitted from the same input link, their transmissions are necessarily serialized (physical constraint) and they cannot arrive at the output port at the same time. In the following paragraphs, the serialization effect and its solution to the Trajectory approach proposed in [8] are briefly recalled.…”

“…Flows crossing an output port h are transmitted In [8], an optimization on the Trajectory approach has been proposed by taking into account the serialization effect. An illustration of the optimization is shown in Figure 6.…”

“…Then the delay of f i is maximized by postponing the last frame arrival of each frame sequence from each input link IP h k (k ∈ {1, ..., k h }) till the time θ. It has been illustrated in [8] that at the output port OP h , there can be frames transmitted before the first frame arrival from IP h 0 . These frame transmissions do not delay frame f i and should be taken into account in the delay computation.…”

“…In [13], [8], the Trajectory approach has been improved by taking into account the serialization of frames sent on the same nodes (called serialization effect in the following). Bauer&al.…”