Research On Service Model And Algorithms Of Resource Allocation In Flexi-Grid Optical Networks

The booming development of internet, especially mobile internet in recent years, has brought in explosive data traffic, larger user scale and more diversified service, which result in a severe problem for current optical network. Fortunately, the occurrence of flexi-grid optical network makes up the inefficiency in spectrum utilization and bandwidth flexibility for traditional WDM optical network, offering another possibility for network improvement. However, the current flexi-grid optical network adopts the same instant processing for all services without considering their detailed requirements like service timeliness. And the development of SDN (Software Defined Network) has also led to a more diversified service features in network. Therefore, how to make the most of service features to allocate spectrum resource more effectively has become a key problem in flexi-grid optical network. In this paper, we will focus on service features in flexi-grid optical network and mainly study the problem of service-based resource allocation. In detail, a service model used to optimize the resource allocation in flexi-grid optical network is proposed and some simulation is conducted for verification. The main work includes but not limited to:Firstly, this paper studies the key features of network service and introduces some attribute-based spectrum allocation algorithms. Based on the attribute-classified service model, we design a novel service model in flexi-grid optical network with the introduction of service queue and scheduler. The model study mainly includes service classification, service buffering/scheduling and priority adjustment. Simulation results indicate that, this new service-based model allows considerations of both practical requirements of service and instantaneous status of network, therefore providing an adaptive adjustment for service strategy. It offers buffering, retry and scheduling for service processing, which lowers the blocking rate and improves the network performance effectively.Secondly, the resource allocation in traditional WSON (Wavelength Switched Optical Network) and flexi-grid optical network is analyzed in this paper. Then we propose a flexible spectrum allocation algorithm based on dynamic expansion of spectrum segment and finish corresponding simulations. Simulation indicates that, this allocation algorithm enables a flexible adjustment and control for the cutpoints between spectrum segments, therefore allowing an adaptive bandwidth allocation for the network based on the service bandwidth variation. This algorithm decreases the existence of spectrum defragmentation in the network and also improves the network performance.Thirdly, based on the current platform, this paper extends and reconstructs the original architecture, establishing a new SDN-based platform for flexi-grid optical network. The service model is implemented in this new platform, and the simulations of service model and allocation algorithms are conducted on it. The new platform reduces the coupling between output simulation results and input service features, verifying the positive influence of service model for performance improvement.