Controller Loose Management And Virtual Network Mapping In Software Defined Networking

Software defined network (SDN), a new network architecture, realizes the centralized, dynamic, and programmable control of the entire network by the virtualization and the separation of application layer, control layer and data layer. It makes management, design, and use of the whole network resource become more flexible. It also is conducive for the innovation and development of network technology.SDN centralized network control platform brings about numerous advantages such as programmability, high flexibility, programmability, and provider independent. However, the centralized control platform brings up issues of scalability and reliability. Hence distributed control plane is built. This thesis presents the controller loose management idea of a network device controlled by multiple controllers. When the number of virtual networks (VNs) deployed by network device reaches a threshold, the controller will stop the communication with the network device. After a period of time, the communication between the controller and the network device is built again. It improves the communication efficiency between the controller and the network device and the controller management efficiency. Based on the above ideas, firstly, this thesis designed the scheme and algorithm of controller loose management, secondly, this thesis quantificationally analyzed the advantages of controller loose management algorithm by building mathematical models of the network device join ratio, the virtual network deployment success ratio, and the communication revenue between the controller and the network device.What the virtual network mapping (VNM) problem involved is how to make the limited substrate network resources support the virtual networks as many as possible. This thesis studied two aspects of VNM research. With the research experience LFB proposed by IETF (Internet Engineering Task Force) ForCES (Forwarding and Control Element Separation), this thesis adds LFB (Logical Function Block) into the previous VNM model. Then the scheme of function block resources sharing and the algorithm of virtual network mapping based on function block resources sharing are proposed. The simulation results show the function block rental cost can be significantly reduced in the function block resources sharing algorithm. This is the first aspect of VNM research in this thesis. The second one is about the node mapping. Firstly, this thesis identified two node mapping ways. They are the substrate node with more remaining resources can be preferentially chose as a substrate mapping node and the substrate node with less remaining resources will be preferentially chose as a substrate mapping node respectively. Then the mathematical models of the two ways are proposed. The experiment results show the first way of node mapping can obtain better performance. Secondly, based on the loss system theory in queuing theory, this thesis builds the performance model. The experiment results show the performance model can well predict the virtual network mapping performance.