Tighter buffer dimensioning in AFDX networks

Abstract

The AFDX (Avionics Full DupleX Switched Ethernet) is the backbone network of most recent avionic communication systems. These systems require deterministic buffer dimensioning for certification reasons. As in such systems, static design is often preferred over dynamic allocation, a dimensioning in terms of frames rather than in terms of bits can be required. A common approach consists in deriving the worst-case buffer size in terms of frames from the worst-case in bits. However, we show that this can lead to an overestimation of the buffer size. Thus, we propose a dedicated approach for a tighter dimensioning. Eventually, the two approaches are compared on a sample AFDX configuration.