Performance enhancement of extended AFDX via bandwidth reservation for TSN/BLS shapers

Abstract

To support mixed-criticality applications, the AFDX may integrate multiple traffic classes: Safety-Critical Traffic (SCT) with hard realtime constraints, Rate-Constrained (RC) traffic requiring bounded latencies and Best Effort (BE) traffic with no delivery constraints. These traffic classes are managed based on a Non-Preemptive Strict Priority (NP-SP) Scheduler, where the highest priority traffic (SCT) is shaped with a Burst Limiting Shaper (BLS). The latter has been defined by the Time Sensitive Networking (TSN) task group to limit the impact of high priority flows on lower priority ones. This paper proposes two bandwidth reservation methods for BLS shapers in AFDX networks. The proposed methods are evaluated on a realistic AFDX configuration. Results show their efficiency to noticeably enhance the RC delay bounds and the SCT schedulability, in comparison to an intuitive method.