Analysis of QoS techniques in OpenFlow networks

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Dr. Gulyás András
Department of Telecommunications and Media Informatics

Today’s networks carry the most diverse variety of traffic. It seems natural that we can browse web pages, while keeping in touch with our friends and relatives or even watch videos at the same time. When computer networks were first created, their constructors couldn’t foresee this kind of variety, and it was inevitable to post-deploy some methods in order to fulfill modern demands.

Although technology has evolved a lot since then, even service providers with the fastest connections have difficulties fulfilling the varying user demands, e.g. when they would like to provide real time services, such as VoIP videoconference besides the aforementioned user requirements. These are the use-cases for which QoS, Quality of Service methods were developed for, which enable us to guarantee bandwidth or latency for a given service over the network even when considerable background traffic is present.

The purpose of my thesis is to examine the possibilities of QoS methods in OpenFlow networks. OpenFlow is an open standard that enables us to change even the most basic packet forwarding mechanisms of a switch without the need from the vendor to expose the device’s inner structure. The standard is being continuously enriched with new capabilities that can be both obligatory and optional services as well. Thus, an OpenFlow capable device can have several approaches to provide QoS, which I cover in my thesis.

For the appropriate analysis I have created a smaller OpenFlow network as a testbed. I implemented QoS packet forwarding using a modified OpenFlow controller and a switch, and I could analyse the results in the testbed. Finally, I have created a user-friendly interface with which users can manipulate the devices’ settings.


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