Research Of Protection And Restoration Scheme In The Elastic Optical Network

Along with the massive emergence of demands to access to the Internet anywhere at any time, endless data traffic is sucking the limited optical fiber bandwidth. The rude spectrum allocation based on the wavelength has encountered the bottleneck of networks capacity and utilization rate of resources. Future optical networks require a more sophisticated and more flexible way to use and allocate the spectrum resource. The spectrum-sliced elastic optical networks (SLICE) are such kind of networks that match the development direction of the future. The characteristics of SLICE include efficient accommodation of multiple data rate, elastic variation of spectrum resource allocation and so on. By taking advantage of adaptability in SLICE, services based on bandwidth squeezed can be provided. These new features also put forward new requirements for the networks survivability. The research about elastic optical networks survivability is of great importance. By applying OpenFlow protocol, the control and data planes are decoupled, networks intelligence and state are logically centralized, and the underlying networks infrastructure is abstracted from the applications. OpenFlow protocol provides a good platform for the networks and application innovation, including the optical network. In this paper, we used OpenFlow protocol implements a simple centralized control plane elastic optical network, which make the networks management much easier. We research the protection and restoration mechanisms in SLICE that applying to the centralized control plane. We also propose a novel mechanism of networks survivability suitable for elastic optical network, and implemented simulation. At the same time, we propose a parallel traffic migration algorithm in recovery process in elastic optical networks of low resource redundancy.The main contribution including innovative research, design and development work is listed as follows.(1) Related background and development of elastic optical networks have been summarized. Properties and advantages of SLICE are introduced. The research meaning of recovery mechanism in SLICE has also been explained.(2) The basic framework of elastic optical network has been introduced. Based on the traditional network survivability mechanism, recovery mechanisms applied to SLICE have been studied by making full use of various advantages of SLICE.(3) The development and advantages of OpenFlow protocol has been briefly introduced. To support the signaling procedure and reliability of elastic optical networks, the extended OpenFlow protocol has been studied and proposed. The framework of OpenFlow-based centralized control plane of elastic optical networks has been illustrated in detail. The procedures and important data structures of extended OpenFlow protocol are also been described.(4) The establishment of centralized control plane of elastic optical networks. The structure of switch and the controller in simulation platform have been illustrated. The realization of link failure recovery mechanisms under the condition of centralized control plane has been studied. The recovery strategies proposed in this paper also have been tested and verified on our testbed.(5) As the last segment of failure restoration, traffic migration has been defined and introduced. And the usage scenario and the necessity of research of traffic migration are also presented. A mathematical model has been established. A heuristic algorithm about parallel traffic migration has been proposed. The algorithm performance is proved through the simulations.