Research On Route Selection Algorithms In Software Defined Networks

The proliferation of mobile demands and multifarious services pose great challenges to service supporting capability of the radio access networks(RANs) and the core network(CN). The software-defined network(SDN) technology which applies new architecture of network centralized control, separates the functions of data forwarding and logic control and achieves the decouple of data layer and control layer, thus is capable of effectively solving the problems of traditional networks such as rigid and closed architecture, highly restricted performance of data transmission and forward, and low resource utilization. Route selection technology is one of the important strategies to guarantee users quality of service(QoS) and realize the improvement of network performance, and has been widely studied by academia and industries. However, the integration of heterogeneous RANs, the complexion of forwarding devices, the complexity of user equipments and diversity of services requirements in SDN-based architecture pose great challenges to route selection. To stress the aforementioned problems, this thesis studies the route selection problems of SDN and aims to achieve the end-to-end QoS guarantee and the improvement of the integrated network performance.As both the characteristics of RANs and CN in SDN will affect the transmission performance of route selection, however, traditional algorithm fails to be considered jointly, and may cause low network resource utilization. To stress the problems, a heterogeneous SDN architecture is proposed in which both the RANs and the CN are virtualized to virtual access points(VAPs) and network slices respectively based on network virtualization(NV) technology. Furthermore, a joint utility optimization based VAP and network slice selection scheme is proposed. To characterize the complicated transmission performance of VAPs and network slices, the concepts of utility function and network calculus are introduced, and the joint utility function of VAPs and network slices is formulated based on which the optimal VAP and network slice combination corresponding to the maximal joint utility can be selected. The simulation results demonstrate the efficiency of the proposed scheme.The existing routing selection algorithms fail to jointly consider user requirements demands, the power consumption and transmission delay during data transmission and forwarding. To stress this problem, a joint power consumption and transmission delay based route selection is proposed in this thesis. To characterize the performance of transmission route, the power consumption and transmission delay of various types of network links are formulated, through which a minimum end-to-end joint cost optimization model is established and characterized as weighted direction graph, which can be solved based on Dijkstra algorithm. Compared with traditional algorithm, the proposed algorithm is capable of achieving the transmission performance enhancement of the users.