Research And Application Of SDN

Along with the development of cloud computing, the virtualization applications on theserver show explosive growth. By the traditional way, in order to make the network properlyperform, there are lots of unrelated network protocols on different network levels. Thetraditional network model tends to be static and can not adapt to the pressures and challengesbrought by the rapid migrations of virtual machines on the server.The hierarchical mechanismof the traditional network requests each layer of the network to consider the problems, such asthe loopback link, the convergence of the network, the consistency of the view in differentnetwork devices. The learning of network information occurs on each network device. Whenthere is a device unable to learn network information due to the wrong configuration or someother reasons, it will have an impact on the entire network.Software-Defined-Networking separates the forwarding layer and the control layer of thenetwork. Openflow, a protocol defined by Open Network Foundation, provides thecommunication mechanism between the network Controller and the forwarding device. Thenetwork Controller sends flow tables to forwarding devices. The forwarding devices receivemessages and forward messages according to current flow tables. The flow table contains thecontrol information covering2to4layers of ISO network model. Using the Openflowmessages, the network Controller could generate a view of the entire network, and thus makethe network under a centralized control.The paper according Openflow agreement made SDN network controller TinyController,TinyController via flow meter control Openflow switches, make the Openflow switch has theshape of the layer two switch. By constructing LLDP packets that can be had from theresearch TinyController topology detection. The network topology is stored in a directedgraph in the TinyController, using the greedy algorithm to obtain the optimal path of networktopology. According TinyController topology detection features, if the cost of every link equal,improved greedy algorithm reduces the time complexity of the algorithm.Finally, experimental platform for TinyController test measures the communicationTinyController switches on Openflow delay generated. Analysis of the flow meterTinyController generated. TinyController generates the experimental network topology andultimately generate the optimal path.