軟體定義網路 (SDN) 是一個新興的網路架構,它開啟了網路可程 式化的可能性。 對於正在發展中的許多軟體定義網路研究計劃而言, 開發一個可以高度準確地模擬使用 OpenFlow 的軟體定義網路的模擬 器是必須的,如此以來才能更正確的驗證並評估嶄新的研究想法及方 向。 但是,目前的模擬器大多是只專注在數據平面的效能 (data plane performances) 或是只專注於以軟體實作 OpenFlow 交換機 (software-implemented switches)。 這使得我們想要去開發一個 OpenFlow 網路模 擬器,可以兼具控制平面 (control plane) 以及數據平面 (data plane) 效 能的正確性模擬,並且可以模擬現在市場上不同廠牌的 OpenFlow 交 換機。 在這篇論文裡,我們在不同的交換機上測量了控制平面及數 據平面的效能 (control plane and data plane performances) 並提出了提高 模擬正確性的效能模型 (performance models)。我們也提出了自動化地 量測交換機效能的方法。 在我們提出的模型中,有一些可以調整的 參數,調整這些參數是為了讓模型可以模擬來自不同廠商,不同實作 的交換機。 這些參數會從我們提出的自動化效能量測實驗的結果所 獲得。 我們執行了實驗去驗證效能模型的正確性,且錯誤率大部分 在30%以下。 再者,我們也將效能模型整合到現有的開源軟體計劃中 的 OpenFlow 模擬器,Mininet/Open vSwitch (OvS),並且進行實驗驗證 效能的正確性。我們將實驗結果與尚未修改的 Mininet/OvS 和欲模擬 的交換機的結果一起做比較,整合效能模型的結果比起 Mininet/OvS 更正確地模擬了交換機的效能。

Software-Defined Networking (SDN) is an emerging network architecture that enables network programmability and efficient network management. Recent research activities on SDN make it important to develop an emulator that accurately emulates OpenFlow-enabled SDN networks in order to verify and evaluate the innovative research ideas. However, existing emulators and simulators focus on either data plane performance or software- implemented switches. This motivates us to develop an OpenFlow emulator that provides accurate emulation on both control plane and data plane performances of an OpenFlow network and supports diverse OpenFlow switch implementations. In this thesis, we conduct extensive measurement studies on control plane and data plane performances on several switches and propose performance models for accurate emulation. Automatic switch performance measurements are also derived. In our proposed models, we have configurable switch-dependent parameters that characterize different switch implementations. Those parameters are generated from our automatic switch performance measurements. We conduct experiments to validate our performance models, and the error rates are mostly under 30%. Moreover, we integrate our performance models with a popular open source OpenFlow emulator, Mininet/Open vSwitch (OvS) and evaluate the performance accuracy by comparing to the results of original Mininet/OvS and the emulated switch. Our results are far more close to the emulated switch than the original Mininet/OvS.

1 Introduction 1
1.1 ContributionsandOrganizations ...................... 3
2 Related Work 4
2.1 OpenFlowEmulators/Simulators...................... 4
2.2 Techniques to Improve Simulation/Emulation Fidelity . . . . . . . . . . . 5
2.3 Performance Measurements and Modeling of SDN Switches . . . . . . . 6
3 Measurement Methodology 7
3.1 ControlPlanePerformanceMeasurement ................. 8
3.2 DataPlanePerformanceMeasurement................... 11
4 Control Plane Performance Modeling 12
4.1 TestScenarios................................ 12
4.1.1 FactorConsiderations ....................... 12
4.1.2 Scenarios.............................. 14
4.2 AdditionalMeasurements.......................... 15
4.2.1 MultipleFlowTables........................ 15
4.2.2 BatchCommands.......................... 18
4.3 MeasurementResults............................ 19
4.3.1 ResultsofSampleSwitch,Pica8P-3297. . . . . . . . . . . . . . 19
4.3.2 ResultsofSampleSwitch,OpenvSwitch . . . . . . . . . . . . . 23
4.4 PerformanceModels ............................ 23
4.5 ModelValidation .............................. 28
5 Data Plane Performance Modeling 35
5.1 TestScenarios................................ 35
5.2 MeasurementResults............................ 37
5.3 PerformanceModels ............................ 37
5.4 ModelValidation .............................. 41
6 Emulator Implementations and Evaluations 48
6.1 Design.................................... 48
6.2 Implementation ............................... 49
6.3 Evaluations ................................. 51
7 Conclusion 53
7.1 FutureDirections .............................. 53
Bibliography .............................. 56

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