針對時效性網路之零抖動可擴展線上排程

Abstract

時效性網路在工業物聯網應用中至關重要，這類應用需要確保通訊的確定性、低延遲以及零抖動，以支持即時控制與同步。然而，工業物聯網網路中大量設備的存在，導致了顯著的可擴展性挑戰。現有方法如時間感知整流器和循環佇列與轉發面臨明顯的限制：時間感知整流器計算複雜度高，限制了其在即時排程場景中的應用，而循環佇列與轉發無法保證零抖動，使其不適用於同步流的排程。此外，現有結合時間感知整流器與循環佇列與轉發的方法在處理同步流時效率不足，仍然難以應對可擴展性問題。為了解決這些挑戰，我們提出了零抖動循環佇列與轉發，這是一種整合排程架構，結合循環佇列與轉發進行初始傳輸，並在最後一跳利用時間感知整流器和重新排序機制來確保流的順序並實現零抖動傳輸。此方法提升了可擴展性並增強了可排程性，使其特別適用於工業物聯網應用。實驗結果顯示，零抖動循環佇列與轉發在多種網路拓撲中相較於現有方法，實現了更高的可排程性與更短的運行時間，有效驗證了其在時間關鍵型工業物聯網環境中的優勢。

Time-Sensitive Networking (TSN) is critical for Industrial Internet of Things (IIoT) applications, which require deterministic communication, low latency, and zero jitter to support real-time control and synchronization. However, the large number of devices in IIoT networks introduces significant scalability challenges. Existing approaches, such as the Time-Aware Shaper (TAS) and Cyclic Queuing and Forwarding (CQF), face notable limitations: TAS incurs high computational complexity, limiting its applicability in online scheduling scenarios, while CQF cannot ensure zero jitter, making it unsuitable for scheduling isochronous flows. Furthermore, existing methods that integrate TAS and CQF face scalability challenges due to the inefficient handling of isochronous flows. To address these challenges, we propose ZCQF (Zero-Jitter Cyclic Queuing and Forwarding), a novel scheduling architecture that integrates CQF for initial transmission and utilizes a reordering mechanism combined with TAS at the final hop to ensure flow order and achieve zero-jitter transmission. This approach improves scalability and enhances schedulability, making it well-suited for IIoT applications. Experimental results demonstrate that ZCQF outperforms existing methods across various network topologies by achieving higher schedulability and shorter runtime, validating its effectiveness for time-critical IIoT environments.