有鑒於近年來網路以及電腦硬體的快速發展，人們對於網路功能的需求也是日益 增加，在軟體定義網路中使用網路功能虛擬化來將各種原先需要硬體配合的網路 功能加以虛擬化並整合一連串的服務成服務功能鏈已經非常常見。但在網路功能 虛擬化當中，每一個虛擬網路功能都將面臨效能的問題，例如像是在網路功能 虛擬化當中，I/O效能將會是很大的瓶頸，因為大量的I/O將會同時產生大量的系 統中斷。儘管目前已經有一些方法像是使用具備SR-I/OV的網路卡來盡可能解決 這一問題，但因為對於現有架構如軟體定義網路契合度不高而不實際。舉個例 子，通常在網路功能虛擬化當中我們常將OpenvSwitch這一軟體定義網路元件運行 在通用伺服器的主作業系統中來管理經過許多虛擬網路功能的網路封包，但是 在SR-I/OV網路卡架構下，網路封包又必須跳過主作業系統到客作業系統，兩者從 而產生了矛盾。因此我們在這用更宏觀的角度提出了一個新的系統架構，藉由修 改適當的OpenvSwitch以及SR-I/OV網路卡驅動程式元件，使服務功能鏈可以盡可 能的克服其缺陷又可以契合現有像是軟體定義網路的架構。

Due to swift Internet technology and computer hardware development in recent years, the demands of network functions are rising. Compared to hardware-based network services, it is faster and more flexible to virtualize the network services and a flows may be processed by multiple network services as a Service Function Chain (SFC). Using Software Defined Network (SDN) is highly popular in the world because it can reduce deployment cost and time. However, the performance of Network Function Virtualiza- tion will be troubled by some congenital drawbacks. For instance, Network Function Virtualization usually suffers from I/O latency because it causes lots of interrupts that decreases CPU utilization. Although this can be solved somehow such as using SR-I/OV network card to reduce the system interrupts, the methods are still not perfect because it is not compatible with existing Software Defined Network system. For example, we often runs OpenvSwitch, an OpenFlow virtual switch supporting Software Defined Network, in general purpose server’s host OS to manage all the network packets forwarded to Virtualized Network Functions (VNFs). However, with OpenvSwitch, network packets must bypass host OS to guest OS when we use SR-I/OV network card. We will lose the benefit of SR-I/OV to enable SDN by using OpenvSwitch. Therefore, we propose an integrated architecture from a wider perspective in system design to overcome main defects described above. We modify appropriate components in SR-I/OV driver and OpenvSwitch to make Service Function Chain constructed by Virtualized Network Functions perform better and compatible with Software Defined Network environment.

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