Desighn And Implementation Of Topology Maintenance And Data Transfer In Publish/Subscribe System Based On SDN

Traditional Internet provides the best-effort service, allows each kind of data to get network resources through fair competition, but it brings limitations to reliable transfer of Publish/Subscribe system, which leads to the danger that important data might be discarded during preemption of network resources.SDN network architecture has a good centralized control feature to achieve the seperation of control layer and forwarding layer. The application can participate in the data forwarding plane according to the business needs. At the same time, the control layer in the architecture has the ability to perceive network topology changes and traffic changes,providing a new solution for topology management and improving data forwarding reliability.Based on current research progress of SDN network architecture-related technology, the existing system is further improved and optimized from two aspects in this thesis. On the one hand, the management system manages topology information and traffic information. The topology information mainly includes the information of network nodes such as clusters, switches and hosts in the network environment. The traffic information mainly includes the information of switch ports and queues. The OpenFlow protocol for the northbound interface provides rich REST-API, which facilitates access to information.On the other hand, setting different priority queues with different bandwidth on the switch port, and encoding the message priority into the matching field of the flow table. Once the data matches successfully, the corresponding enqueue operation will be performed, and then the bandwidth adjustment strategy based on time-dealy of queue will be implemented to increase the utilization of port bandwidth and ensure high-priority messages to arrive accurately.Compared with the original system, the improved Publish/Subscribe system adds the display function of network topology, switch and queue traffic information. The feedback mechanism of queue bandwidth is established to optimize the data forwarding process.Multi-cluster OpenFlow experimental network is constructed applying mature virtualization technology. Test results reveal the feasibility and good performance of the system.