| Nowadays, with the rapid development of Internet, various applications and services emerge in endlessly which makes network traffic grow fast. However, the issue of limited network resource has always been a bottleneck to the development of network. Thus, resource management is of paramount importance. In spite of the fact that technology and innovation continue to evolve, our network infrastructure system(e.g., all kinds of switches and routers) has been maintained almost in the same shape for decades. Neither the hardware or software of old network infrastructure cannot satisfy the requirements of the explosive information. It is imperative to upgrade or even reform the current network system.The explosive growth of real time applications requires stringent Quality of Service(QoS) like latency and bandwidth. Traffic engineering is getting more attention from network carriers and researchers as an important way to improve the performance of network. Nevertheless, the classical IP network cannot provide a high QoS guarantee for real time applications because of the shortcomings in its routing and forwarding mechanisms. This has become a bottleneck of the research of IP-based traffic engineering.Software-defined Networking(SDN) came into being in this situation. It is a creative architecture in computer networking where the control plane of network is decoupled from the data plane. So it is possible to control the network in a centralized way. Also, it simplifies network management, facilitates study and research and accelerates innovation of networking. One mechanism that allows the control plane to communicate with the data plane is Open Flow. Thanks to the openness and programmability of SDN, the network operators could write high-level control program that defines the behavior of an entire network.This thesis exploits the use of SDN in conjunction with OpenFlow to manage different network services with a high QoS. In particular, we consider a Video Streaming service and a Data Transfer service. Firstly, we propose a QoS management architecture which allows us manage the network in modular way. The core idea of the architecture is to assign a flow to an optimal path to avoid congestion and enhance QoS taking into account both the link parameters(e.g., packet loss, latency, and available bandwidth) involved in the path and the flow requirements. Specifically, based on the Multi-Commodity Problem and the Constrained Shortest Path problem, the optimization problem is formulated as a Multi-Criteria approach. Moreover, because of the introduction of two adjustable scale factors which can be used to set the weights of packet loss and delay, it is possible to provide flexible QoS operation according to different requirements of various scenarios.Then, we integrate our architecture into a Mininet-based SDN simulating environment and test our architecture in different scenarios. The results show that, compared to the traditional solution given by the emulator, the performance of our architecture is improved in aspect of enhancing QoS. Then, changing the network conditions, it is possible to find and deploy the new optimal path for a specific flow to guarantee its QoS. |
