Research And Design On Incremental Deployment Of Software- Defined Networks

Software Defined Network (SDN) is viewed as the best solution for flexible and efficient management of the network, by which we can properly engineer the traffic according to the state of the global network. However, due to the high cost, imperfect network services, incompatible protocols of SDN networks, it's difficult for all the legacy switches to be replaced by SDN equipment in a short term. Thus, in the early stages of SDN network deployment, it's imperative to replace some legacy switches with SDN equipment in traditional networks. This deployment strategy will not only enhance the flexibility of the network control and gain other advantages of SDN, but also benefit from the high stability, scalability and technology maturity of the traditional networks.In such a hybrid SDN network, a customized server is needed for most of the current solutions, which is used to obtain the hybrid network load for SDN controllers. Known all the link load, the SDN controller can drive traffic to the paths with lower load to balance the network load. While these hybrid network solutions can achieve their goals, there are some problems of these solutions. Firstly, the customized server is not necessary. And after adding this customized server, the architecture of this hybrid SDN network becomes complicated, and it needs higher budget for operators to deploy and maintain the network. In addition, the ability to engineer the traffic of current hybrid SDN solutions is not satisfactory. Some randomly choose the places of SDN switches, some can only have a better performance when the network load is predictable, and some always have a relatively weak ability to engineer the traffic. So how to maximize the ability of engineering the traffic is still a problem to be solved.Due to the problems above, we propose a new SDN network deployment solution. In this solution, we removed the customized server. Our goal is to obtain all the link load by deploying less SDN switches. Meanwhile, by properly selecting the places of SDN switches, we improve the ability of engineering the traffic although the network load may unpredictable. Thus, this solution can not only reduce the cost of deploying hybrid SDN networks as well as the communication in networks, but also improve the ability to engineer the traffic.The second goal of this paper is improving the ability of engineering the traffic although the network load may unpredictable by properly replacing given amount of traditional routers to SDN switches. In this way, enterprises can deploy the amount of SDN switches according to their budget.Finally, we set up a physical environment by Floodlight Controller and Pica8 switch, and by comparing with other solutions, we verify the correctness and validity of our proposals.