Study On The Key Problems Of Optical Network Controller Based On NOX

With the rapid development of optical network technology, optical network technology has evolved from Synchronous Digital Hierarchy(SDH) to Wavelength Division Multiplexing(WDM) network and Optical Transport Networks(OTN). Although the capacity of the traditional optical networks has greatly increased with the rapid development, the shortcomings of traditional optical networks have been unfolded gradually. The traditional optical networks adopt distributed and closed-form control plane, which does not provide standardized control interface. Thus, it is hard to customize management strategies for optical networks, and the logical topologies provided by the optical netwroks aslo can not configured dynamically according to the changing traffic demands. Recently, the SDN technology is considered as a promising solution to addressing management isssues of the traditional optical networks. SDN technique separates control planes from the network equipments, and the separated control plane runs on a logically centralized controller. SDN provides a standardized north interface for applications and used standarlized control protocol to control the network devices. As a result, SDN makes the control of optical networks more flexible.In SDN capable optical networks, the controller is the brain, which controls and manages the whole network. So, this thesis mainly studies the key technologies of the optical network controller based on NOX platform.Firstly, the second chapter of this thesis first gives a detailed framework of optical network controller based on NOX platform and OpenFlow control protocol, and then designs and implements the interface protocols between the network controller and applications, including user applications and network applications, the interface protocols between the network controller and network devices.The third chapter of this thesis realizes the design of optical network virtualization based on FlowVisor, which divides each port of optical network equipment into multiple virtual ports, with each virtual port occupying a certain amount of wavelength resources. As a result, the division of the virtual optical networks is accurate to each wavelength of each port.Secondly, the fourth chapter of this thesis studies the static virtual optical network design problem. Differing from the traditional optical network design problem, the static virtual optical network design problem needs to minimize the amount of virtual nodes in order to reducing the complexity of the management of each virtual network. This chapter first formulates the static virtual optical network design problem as a Mixed-Integer Linear Programming problem, and then proposes an efficient heuristic algorithm to solving it in large-scale networks. At the end of this chapter, the effectiveness of the algorithm is verified by simulation.Finally, the fifth chapter of this thesis studies the dynamic virtual optical network design problem. In dynamic scenario, the traffic demand is no longer a fixed traffic matrix, but a set of traffic matrices corresponding to several time periods. The goal of the dynamic virtual optical network design problem is designing a unified mapping scheme of virtual networks for the set of traffic matrices. In order to solving this problem, three heuristic algorithms with different performances and complexities are proposed, and a comparison of performances is made for the three algorithms.