在現今網路通訊技術的蓬勃發展之下，網路服務型已隨之改變，現今資料儲存、運算與服務方式紛紛走向虛擬化與雲端化，過去傳統網路架構與服務方式逐漸不符合需求。軟體定義網路提供一個可程式化、更靈活且更方便網路管理與設置的環境，而網路功能虛擬化將多種類型的網路服務虛擬化，降低網路建置之複雜度，亦解決原先網路功能專屬設備間相容性的問題，提升網路配置的效率，藉由上述兩種技術相互配合，提高網路環境建置效率與降低網路維護的難度。
本研究致力於高效能與高可靠度之網路功能虛擬化系統設計，網路功能虛擬化中介系統依據使用者的需求進行網路功能的配置，針對環境中已啟動之網路功能服務進行效能分析，選擇適當之網路功能進行配置工作，規劃出合適之網路功能服務鏈給予使用者使用，並於負載變化時視情形調整負載量，確保使用者能有較良好的服務品質，亦為使用者規劃不同等級的權利，解決因規劃不完善所造成的缺失，確保擁有較高優先權利使用者能有較高之服務品質保證。為了將中介系統的決策應用於整體網路之中，SDN控制器運用南向接口與網路功能虛擬化中介系統進行通訊，控制器接收網路功能虛擬化基礎架構的資訊以及中介系統的決策事項，規劃整體網路環境，實現軟體定義網路與網路功能虛擬化之結合作業，提升整體網路的運作效率。
本研究提出網路功能服務鏈配置機制與網路功能資源調整機制，藉此提升網路功能運作效率。中介系統分析虛擬網路功能的使用情形，挑選最為適當的網路功能並加入於服務鏈中，擬定出符合使用者需求之服務鏈。中介系統亦隨時監視虛擬網路功能的使用情形，依據情況調整負載分配，解決網路功能使用效率不彰的問題。本研究提出之網路功能虛擬化系統設計，能夠有效提升約30%的網路使用效率，並降低封包遺失率以提升網路服務可靠度約1.5%。

With the rapid development of network communication technology today, the type of network services has been changed. Data storage, computing, and the type of network services have become virtualization and the cloud. Network architecture and the type of network services in the past do not meet the needs gradually. Software-defined networking provides a programmable, flexible, and easily management and setting for network environment. Network function virtualization is able to virtualize the variable types of network function, reduce the complexity to setup the network environment, and solve the compatibility issues of network function devices, to improve the efficiency to build the network. With the complement between above technologies, the efficiency of setting the network environment has been improved and the difficulty of maintaining the environment has been decreased.
This work proposes network function virtualization middleware to improve the efficiency and reliability of the network environment. Middleware analyzes the utilization of virtualized network function to make decisions of how to build the service chain. In addition, Middleware will monitors the NFV environment periodically to make sure that all virtualized network functions can work efficiently. If there are any virtualized network function in heavy-load or light-load state, the resource manager in middleware will adjust the load in the virtualized network function to distribute the load in the virtualized network function. SDN controller receives the decision and the information of network function virtualization infrastructure by southbound interface to setup the overall network environment.
This work proposes the service chaining mechanism and resource allocation mechanism in network function virtualization middleware. Middleware will analyzes the virtualized network function in the environment to schedule the suitable service chain for user. In addition, middleware also monitors the resource utilization about the virtualized network function and adjust the load of virtualized network function depend on the situation to decrease the problem of ineffective usage of the network function. Based on the proposed network function virtualization system, the network efficiency has improved about 30% and the reliability has improved about 1.5% by reduce packet loss rate of the network.

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