ADA: Asynchronous Deterministic Access for Time-Sensitive Networking

Time-Sensitive Networking (TSN) enables deterministic transmission by requiring end systems to support 802.1Qbv and 802.1AS standards, which makes practical deployment challenging, especially for asynchronous end systems (AES) such as various legacy devices already deployed in industry. We present a novel deterministic transmission scheme for asynchronous time-triggered flows from AES. First, we design an Asynchronous Deterministic Access (ADA) mechanism with two components: "Async to Sync" and "Latency Adaptation." These components allow an AES flow to wait for its scheduled period, ensuring a theoretical end-to-end (E2E) deterministic delay. Second, we propose an ADA scheduling model to optimize the scheduling periods for AES flows. However, latency adaptation may cause AES flows to conflict with other flows at the final hop switch. To address this problem, we propose a conflict resolution mechanism that determines safety distances between flows to reduce delay jitter. Finally, we implement ADA in our switches and evaluate its performance in terms of E2E delay and jitter. ADA is shown to achieve E2E delay and jitter reductions of 57.1-83.5% and 60.7-85.4%, respectively, over SOTA methods.