Priority re-assignment for improving schedulability and mixed-criticality of ARINC 664

Abstract

ARINC 664, which is a heavily used protocol for modern avionics networks, is preferred due to its simplicity although its mixed-criticality support is limited. Time Triggered Ethernet (TTEthernet), and IEEE Time Sensitive Networking (TSN), which utilize time synchronized schedule, are more suitable for supporting mixed-criticality applications; however, both require a fault tolerant time synchronization that makes the certification process more challenging. In this paper, we propose a novel dynamic priority assignment (DPA) concept together with the burst limiting shaper (BLS) from the IEEE TSN standard to enhance the schedulability and the mixed-criticality support of ARINC 664. The decision of flow re-assignment to a new priority class is done by calculating the high priority (HP) and low priority (LP) class worst-case delays using the network calculus framework. The numerical results show that the class utilization rates can be significantly increased by using the DPA concept with and without the BLS while the deadline constraints for all classes are satisfied. Thus, the DPA can improve the schedulability and mixed-criticality of ARINC 664 without using any time synchronization mechanism.