Packet scheduling for AFDX switch under hard time constraints

AFDX (avionics full duplex switched Ethernet) is a switched interconnection designed to meet requirements related to the ever increasing demand for civil aircraft such as A380. A packet scheduling scheme on hard real-time performance in AFDX switch was studied. Based on the dual-priority-message scheduling principle of AFDX protocol, an analytical expression of its key parameter was derived, and a new packet scheduling scheme (DP-LM, dual priority-load match) under hard real time constraints was proposed. The different factors such as scheduling progress, key parameter and load-match method between dual-priority-message scheduling and single-priority-message one were deeply compared, and example resultants indicate that low priority message can impact on real time transmission for high priority one.