運用Robust Optimization設計擁有頻寬保證的OpenFlow虛擬網路

Design of Bandwidth Guaranteed OpenFlow Virtual Networks Using Robust Optimization

鍾燿全(Yao-Chuan Chung)

指導教授 ： 李詩偉

國立中正大學/工學院/通訊工程學系/碩士(2014年)

摘要

在本論文中，我們討論了如何設計和實現運用OpenFlow來配置虛擬網路(Virtual Network)的問題。跟大多數現有直接在實體網路對頻寬進行分割的方法不同的地方是，我們將流量的不確定性和統計多工(Statistical Multiplexing)一起加入考慮。在我們的系統中，使用者可以指定自己所需的虛擬網路拓撲結構(Topology)和各個不同大小流量的虛擬鏈結(Virtual Link) 。其中每個virtual link都有包含相對的頻寬，分別為保證頻寬(Guaranteed Bandwidth)和上限頻寬(Upper Limit Bandwidth)。每個使用者會被保證任何時候只要在自己的guaranteed bandwidth下就不會被其它使用者的頻寬使用率所干擾。此外，使用者可以在一段短時間內將使用頻寬達至其上限頻寬，而且封包遺失率(Packet Loss Probability)不會超過一個預定的值。此功能使OpenFlow網路在一段時間內用戶的傳輸速度有大幅變動的時候還能為用戶的網路提供QoS(Quality of service)保證。
我們運用Robust Optimization來為這個問題建模，用來連帶的確定允入控制和virtual link的路由(Routing)。我們進一步提出一個使用市售OpenFlow的交換機(Switch)來實踐我們的設計，透過模擬和實驗來證明和表現我們的方法。而實驗的結果表明，我們這個設計能成功容忍OpenFlow網路流量下的不確定性。由於提出的方法可以高效率的使用頻寬，它比不考慮statistical multiplexing的方法下，可以容納更多的virtual network。

關鍵字

Robust Optimization ； 虛擬化網路設計 ； OpenFlow網路虛擬化 ； Qos的管理

並列摘要

In this paper, we address the OpenFlow virtual network (VN) design problem. Unlike most of the existing approaches that directly performing bandwidth slicing on the physical networks, we take traffic uncertainty and statistical multiplexing into consideration. In our system, a user can specify the desired VN topology and the capacity for each virtual link (VL). The bandwidth descriptor for a VL consists of a pair of values for guaranteed bandwidth and upper limit bandwidth. Each user is guaranteed to own the guaranteed bandwidth at any moment without interferences from the bandwidth usages of the other users. Moreover, a user can successfully uses bandwidth up to its upper limit in short time with packet loss probability no more than a pre-defined value. This feature enables OpenFlow networks to provide QoS for network services with bursty traffic.

We model this problem as a robust optimization program to jointly determine admission control and VL routing. We further present an approach for implementing the proposed design using commercial available OpenFlow switches. The performance of the proposed approach is evaluated through simulations and experiments. The results indicate that the proposed design can successfully tolerate traffic uncertainty in OpenFlow networks. Since the proposed approach can use bandwidth with high efficiency, it can admit more VNs than the one without taking statistical multiplexing into consideration.

並列關鍵字

Robust Optimization ； Virtual Network Design ； OpenFlow Network Virtualization ； QoS Management

參考文獻

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