隨著工業的發展，物聯網裝置有了新的定義，稱作工業物聯網，其主
要是針對工廠環境中有著低延遲、高吞吐量需求的裝置，因此有人提出透過 5G 毫米波來滿足這些裝置。然而毫米波最致命的缺點在於容易受到環境干擾，使得鏈路從原先視距 (Line of Sight, LoS) 的狀態轉變為非視距 ( Non-Line of Sight, NLoS)，雖然透過調整調製編碼方案 (Modulation and Coding Schemes, MCS) 可以盡可能的維持鏈路的可用性，但工廠內有著大量金屬材質的障礙物，導致會有經過 MCS 調整後依舊無法傳輸的NLoS 情況。我們假定鏈路在 LoS 時有最大頻寬，並將 NLoS 狀態細分成兩種，若頻寬小於最大頻寬且不為零則稱為部分遮擋 (partial blockage,pb)，若頻寬為零則稱為完全遮擋 (full blockage, fb)。我們基於軟體定義網路 (Software-Defined Networking, SDN) 的架構提出可靠性與公平性的多路徑路由 (Reliable and Fairness Aware Multi-path Routing, RFAMR)的路由策略預防性的保護該段鏈路，當發生 pb 時我們提前對於該段鏈路上的流量進行分流保護，藉此減少當該段鏈路轉為 fb 時，等待路由路徑更新時的掉封包比率。此外我們透過預先處理多條備用路徑的方式，降低鏈路變化時的處理時間，用此確保受影響鏈接的可靠性和其餘鏈接的公平性。根據評估結果證明了，RFAMR 在處理類似場景與問題時，有著更短的處理時間，以及轉移鏈路後有著較好的負載分佈，如此一來就可以避免壅塞問題。

As industries have developed, the concept of Internet of Things (IoT) has expanded to Industrial Internet of Things (IIoT), focusing on factory devices that demand low latency, high throughput, and strong reliability. Some propose using Fifth Generation (5G) millimeter-Wave (mmWave) technology to cater to these devices. However, the major limitation of mmWave technology is its sensitivity to environmental interference, often causing a shift from Line of Sight (LoS) to Non-Line of Sight (NLoS) conditions.
While adjusting the Modulation and Coding Scheme (MCS) can help maintain link availability, the presence of many metallic obstacles in factories can still lead to unsuccessful NLoS transmissions. In our study, we assume that the link achieves its maximum bandwidth under LoS conditions. We further subdivide the NLoS state into two categories: partial blockage (pb), where the bandwidth is less than the maximum but not zero, and full blockage (fb), where the bandwidth drops to zero. We propose Reliable and Fairness Aware Multi-path Routing (RFAMR), a proactive strategy based on Software-Defined Networking (SDN), to tackle these challenges. RFAMR proactively safeguards links during pb by rerouting traffic and minimizing packet loss, especially when transitioning to fb. We streamline RFAMR by pre-processing backup paths, reducing time during link changes and ensuring both reliability and fairness across links. Our simulation results confirm that RFAMR speeds up processing and balances load more effectively after switching links, thus preventing congestion in comparable scenarios.

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