Design And Implementation Of Business-related Routing Management Scheme In OpenFlow Network

With the rapid growth of network services, network traffic is growing rapidly. The network management is facing many challenges, such as traffic engineering, path optimization, quality of service and so on. How to effectively solve the routing optimization problem so as to ensure a certain quality of service has become a research focus in the industry. But traditional routing management schemes have many drawbacks, in which the rate is not high. The fundamental reason is that the traditional TCP/IP architecture is closed and cured. Distributed switching equipment cannot use standard protocols to understand the overall picture and dynamically access to the network resource usage and link state.Software Defined Network achieved a new network architecture, in which forwarding plane and control plane are separated. With the advantage of centralized control of the central controller, it is able to handle complex traffic models. It is flexible, programmable and can be deployed quickly.According to the traffic distribution and link state, it can dynamically adjust link load. In sum, it makes up for the defects of traditional routing management schemes and has a unique advantage in routing management.In this thesis, the proposed routing management scheme includes two parts, which are the initial route selection and the rerouting selection. The scheme use SDN controller to collect the resource usage, compute network topology and monitor network status. Before the flow transmits, the controller selects the appropriate proportion of each measure for the flow based on the business attributes, then calculates the overall measure of each link and plug them into the improved Dijkstra algorithm to calculate the optimal initial route. In the process of the flow transmission, the SDN controller constantly monitors link state. Once the load balancing parameter exceeds a set threshold,it indicates that the link is congested and the rerouting strategy will be scheduled immediately. The controller selects the appropriate flow to transfer based on the business attributes and calculates the candidate paths as well as their transfer overheads so as to select the rerouting path. Experiments show that compared to the initial routing strategy and the widely used ECMP, the initial routing strategy has better performance in terms of bandwidth utilization and transmission delay. At the same time, the rerouting strategy is also effective. It can detect congestion and transfers the flow in time that the packet loss rate reduces significantly and the the link utilization increases.