下世代光數據中心網路之關鍵核心技術-子計畫四：下世代光數據中心網路之光互連技術

Abstract

數據中心網路(DCN)被視為支援未來雲端運算及興起中之分散式計算的最重要技術之一。下世代 數據中心網路最根本的挑戰是如何將指數成長的巨量(如：數十萬部)伺服器以有效率且低成本的方式 連接在一起，同時滿足數項重要的條件：高可擴展性、高吞吐量、高容錯力、低延遲、無封包遺失及 低功率消耗。由於有限的吞吐量及高功率消耗，目前使用電訊號的數據中心網路已經成為數據中心其 持續成長的服務能力之主要技術瓶頸。同時，過去二十年來光網路技術在長途、都會及區域(存取)網 路領域中已成為連結通訊節點的最卓越技術。眾多研究人員投注大量心力於研究如何使用光通訊及光 交換機技術實現數據中心網路，也就是所謂的光數據中心網路。 在這個整合計畫中，我們將透過四個子計畫之間的合作，投入研究開發下世代光數據中心網路的 關鍵核心技術。子計畫一(主持人：楊啟瑞教授)負責數據中心網路架構整體的設計與模型化，以及用 於其中的分波長多工光封包交換機系統之設計、分析、與原型製作，目標是達到前述之數據中心網路 的需求。子計畫二(主持人：田伯隆教授)負責最佳化邏輯數據中心拓墣與路由路徑在流量負載情況變 動下之動態運算，目標是達成最大吞吐量與最小之功率消耗。而該子計畫在分波長多工光交換機系統 上，則負責設計能達到QoS 保證之類神經網路平行化封包交換排程。子計畫三(主持人：馮開明教授) 負責設計與開發高效節能且各種調變格式皆適用之波長轉換技術，其用於數據中心網路中之分波長多 工光交換機系統。子計畫四(主持人：陳智弘教授)負責高頻寬使用率與高階調變格式之平行化光連結 技術，目標是滿足交換器或數據中心之間，不斷增加之高密度、長距離、價格低廉的光連結需求。

Data center networking (DCN) has been envisioned as one of the most prominent technologies for supporting future cloud computing and ever-increasing distributed computing applications. A fundamental challenge in next-generation DCN is how to efficiently and cost-effectively interconnect an exponentially increasing number (e.g., hundreds of thousands) of servers while simultaneously meeting a multitude of requirements. The crucial requirements include high scalability, throughput, fault tolerance, low latency, no loss, and low power consumption. Due to limited throughput and large power consumption, electrical-based data center networking has become a technological bottleneck and a dominant factor limiting the continued scaling of processor performance. Meanwhile, optical networking has been a preeminent technology for connecting telecommunicating nodes in the long haul, metro, and local/access geographic areas over two decades. Together, researchers have recently drawn tremendous attention and interests to the realization of DCN by means of optical transmission and switching technologies, referred to as optical-based DCN. In this integrated project, we devote to discovering and developing the key enabling technologies for next-generation optical-based DCN through research collaboration among four subprojects. Sub-project 1 (PI: Prof. Maria C. Yuang) focuses on the design and modeling of the overall DCN architectures; and the design, analysis, and prototyping of a WDM optical switching system inside the DCN, targeting at achieving the aforementioned DCN requirements. Sub-project 2 (PI: Prof. Po-Lung Tien) focuses on the dynamic computation of an optimized logical DCN topology and routing paths under changing traffic loads and patterns, subject to achieving maximum throughput and minimum power consumption. For the WDM optical switching system, the subproject undertakes the design of neural-network-based parallel packet scheduling with QoS guarantee. Sub-project 3 (PI: Prof. Kai-Ming Feng) aims at the design and development of the modulation-transparent and energy-efficient wavelength conversion techniques for the WDM optical switch system inside the DCN. Sub-project 4 (PI: Prof. Jyehong Chen) undertakes parallel optical interconnect techniques that are of high bandwidth-efficient and high-order modulation format, in order to meet the demands for the growing needed dense, distant, and cost-efficient optical interconnects between switches or data centers.