SDN軟體定義網路，是一種新的以軟體為基礎的網路架構及技術。最大的特點為將傳統二、三層網路設備的控制功能與設備本身數據轉發功能進行分離。由於分離後的控制功能集中統一管理，且其具有軟體設計的靈活性，因此，網路管理人員對底層設備的資源控制變得更加容易，進而大大提升網路自動化管理能力，並有效解決目前網路系統所面臨的如網路拓樸的靈活性差，規模擴充受限等問題。
近年來隨著寬頻上網，物聯網，雲端計算，移動裝置等新技術及新業務的快速發展，在愈來愈多各種型態連網裝置快速增加的情況下，同時也使人們對IP位址的需求日增。然而目前IPv4卻無法針對此需求，提供一個相對大量的位址，也因此對於IPv4到IPv6網路的升級有其迫切性與必要性。IPv4過渡到IPv6網路目前提出的方法有三種：Dual Stack、Tunneling以及Translation。Tunneling及Translation皆有其效能上的瓶頸，為過渡期間的應用技術。目前主要推動的技術為Dual Stack，在Dual Stack模式下，可以由IPv4網路逐步演進成IPv4與IPv6共存互通，最後再形成以IPv6為主的網路。現階段愈來愈多的IPv6設備與節點，為順利的連接舊的IPv4與新的IPv6網路，藉由具有Dual Stack能力的SDN交換機網路設備，將是個有效的解決方案，也將使得IPv6網路的管理及升級更具有彈性。SDN、IPv6為現今幾個熱門的研究議題，看似不同領域的電腦相關技術，然而若使上述幾種技術相互連結使用，將使得未來之網路環境更具備可擴充性、可管理性、靈活性與敏捷性。
為了解SDN交換機上的效能，本論文提出一個測試平台架構。利用Linux系統做為待測網路設備，並在待測網路設備上模擬Bridge、Router、Open vSwitch SDN交換機等不同環境。測試端為Linux系統，並使用Iperf測試軟體，透過對待測網路設備不同模擬環境下發送不同大小的封包做效能測試。實驗中同時也量測IPv4網路協定，以作為和傳統網路效能的比較。另外，也量測了SDN交換機同時在IPv4及IPv6雙協定的負載下，和單獨的IPv4協定或IPv6協定做效能上的差異比較。最後，也模擬同時在多主機下對待測網路設備進行封包的發送與接收，以測試SDN交換機在多主機下的負載狀況。
經由測量的數據分析，IPv6在Open vSwitch SDN交換機上運行效能幾乎等同於傳統的IPv4，也驗證IPv6在交換機上的可行性。此外，當SDN交換機同時運行在IPv4和IPv6雙協定環境下，在整體效能的表現上和單獨運行單協定相比幾近相同，也證明SDN交換機同時運行在雙協定下的可行性。由多主機負載的實驗數據分析，在以UDP協定做資料傳送時，愈多的主機因為資源的競爭問題愈大外，間接也會造成愈多packet loss。並且對較大的封包，packet loss的問題也愈嚴重，但相對來看，在以TCP協定做資料傳送時，total throughput的瓶頸則決定於網路卡的效能，即效能愈好的網路卡，愈能提升多主機環境下的total throughput。 / Software Defined Network (SDN) is a new software-based network architecture and technique. The main characteristic is to separate the control functions and the data forwarding functions of the traditional layer 2 or layer 3 network devices. Since the separated control functions can be centralized management with software design flexibility, thus network managers can control the underlying resource device easier, which greatly enhances the ability to automate network management as well as effectively resolves the problems confronted by conventional network system, such as lack of network topology flexibility, limited network scalability.
In recent decades, along with broadband Internet access, Internet of Things, cloud computing, the rapid development of new technologies and the rapid increase of network devices, it has increased the demand for IP address to a great extent. While IPv4 can not meet the current demand to offer a relatively large number of addresses and thus it is urgent and essential to upgrade IPv4 to IPv6 network. Transition from IPv4 to IPv6 network currently is proposed in these three ways which respectively named Dual Stack, Tunneling, and Translation. Tunneling and Translation have their performance bottlenecks and only Dual Stack mode can be gradually evolved from IPv4 to IPv4 and IPv6 coexistence network, eventually toward the IPv6-based network. There are increasing numbers of IPv6 devices and nodes with the aim to connect IPv4 network to IPv6 network, through SDN switch with Dual Stack network which would be an effective solution. It makes the IPv6 network management and maintenance more flexible. IPv6 and SDN are two hot researching issues currently. If they can be linked with each other, it will be more scalable and flexible for the network environment in the future.
In order to understand the effectiveness of the SDN switch, this paper presents a test platform architecture. Using Linux systems as a Device under Testing, we simulate Bridge, Router, Open vSwitch SDN switch network equipment on it. Test end is Linux system, and Iperf serves as a test software. Through simulation of the Device under Testing in different scenarios, we have performed many tests on different sizes of packets. The experiment also measures IPv4 network protocol and compares with traditional network. In order to compare with the performance of separate IPv4 or IPv6 protocol, the loading of SDN switch running both of IPv4 and IPv6 dual protocol is measured. Finally, simulation on multi-host is tested under Device under Testing in sending and receiving packet which is to test SDN switch under a multi-host loading conditions.
Through the analysis of the measured data, the performance of IPv6 running on the Open Switch SDN switch is equivalent to that of the traditional IPv4. It also proves the feasibility and efficiency of IPv6 on the switch. In addition, when SDN switch running in IPv4 and IPv6 Dual Stack mode simultaneously, the overall performance is almost exactly the same as single IPv4 or IPv6 protocol, which proves the feasibility of SDN switch in Dual Stack mode. Based on the analysis of multiple-host loading, UDP protocols were used during data transfer. Apart from multi-hosts with more competition for resourcing issue, a packet loss will be aroused indirectly. We observed that larger packets can cause more packet loss. However, with TCP protocols during data transfer, total throughput bottleneck is determined by the effectiveness of the network card. Therefore, the better the effectiveness of the network card is, the higher total throughput can be provided in multi-host environment.
| Identifer | oai:union.ndltd.org:CHENGCHI/G0101971021 |
| Creators | 蔡明志, Tsai, Ming Chih |
| Publisher | 國立政治大學 |
| Source Sets | National Chengchi University Libraries |
| Language | 中文 |
| Detected Language | English |
| Type | text |
| Rights | Copyright © nccu library on behalf of the copyright holders |
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