A Lightweight Asynchronous Scheduling Solution for Large-scale Deterministic Networks

Deterministic scheduling is critical for real-time industrial applications requiring predictable, low-latency communication. Existing mechanisms, primarily designed for time-triggered and periodic traffic, struggle to manage bursty traffic effectively and violate latency bounds for low-priority classes within periodic traffic. This paper identifies a latency violation issue in Multiple Cyclic Queuing and Forwarding (Multi-CQF) and Paternoster caused by misaligned cycles across traffic classes. To address this, we propose two solutions: Hybrid Scheduling with Strict Priority and Packet Urgentness (HSSU) and Latency- and Jitter-Bounded Deficit Round Robin (LJB-DRR). HSSU enhances Multi-CQF and Paternoster by introducing class urgentness on top of Strict Priority (SP), resolving latency violations and enabling flexible cycle time configurations. LJB-DRR achieves equivalent latency bounds with a simplified queuing structure. It ensures bounded latency for periodic and bursty traffic through a two-dimensional scheduling mechanism. Evaluation shows that LJB-DRR reduces bursty traffic end-to-end latency by at least 65.82% and significantly lowers packet loss.