Research On Flexible Networking And Resource Optimization Technologies In Software Defined Optical Networks

The emergence of new technologies such as cloud computing,Internet of Things,artificial intelligence and 5G brings new opportunities and challenges to the development of optical networks.With the centralized control architecture,the technology of software defined optical networks(SDONs)realizes the open network functions and efficient management.However,due to the diversity of application scenarios and the differences of user requirements,SDONs are facing new problems and challenges,which can be summarized as two aspects.The first is to design a flexible networking scheme to meet the high-performance requirements of radio networks.The second is to study the algorithms of resource optimization to realize the high-efficiency utilization and flexible provisioning of spectrum resources.For the above two problems in SDONs,with the support of the National 863 Program,this paper focuses on two application scenarios,i.e.5G optical access and multi-domain networking.At the data layer,this paper designs a flexible networking architecture for 5G optical access.At the control layer,this paper proposes a spectrum defragmentation algorithm for multi-domain optical networks.At the application layer,this paper realizes the flexible provisioning of bandwidth and virtual optical networks.This paper has completed the following four innovative work.Firstly,for the flexible networking problem of optical transport in 5G,this paper proposes the concept of Flexible RAN(F-RAN),which supports flexible split of radio functions and configurable optical transport.SDN architecture is adopted to realize the orchestration of radio networks and optical transport networks.Based on different distributions of baseband functions,F-RAN has two variants,i.e.,partially centralized F-RAN and fully distributed F-RAN.The F-RAN concept has been applied to a use case where radio coordination is used to manage radio interference.We assume an optical transport network with both ring and star topology.In terms of wavelength and transponder usage,the performance of F-RAN is evaluated in different interference levels.Simulation results show that compared with C-RAN,F-RAN can reduce the usage of fiber resources in the same interference level.Secondly,to reduce the spectrum fragmentation in multi-domain optical networks,this paper proposes a Multi-Domain Defragmentation(MD-DF)scheme with minimum Controller Participation Degree(CPD),which is based on hierarchical control architecture.The concept of CPD is introduced to quantize the times domain controllers are involved in multi-domain defragmentation.Based on whether the potential blocked lightpath goes through inter-domain links,the MD-DF scheme includes two scenarios,intra-domain DF and inter-domain DF.The proposed scheme is implemented in SDN control plane and experimental results validate its overall feasibility.Meanwhile,the performance of the proposed scheme is evaluated in simulation.Simulation results indicate that the MD-DF scheme can optimize the utilization of spectrum resource and achieve a better blocking probability.Thirdly,to realize dynamic bandwidth provisioning for private line service,this paper proposes a novel Data Analysis-based Autonomic Bandwidth Adjustment(DA-ABA)scheme.The trend of traffic variation for the next period is predicted by analyzing the traffic monitoring data of current period.Based on the predicted traffic load,the DA-ABA scheme adjusts the bandwidth for the next period.The scheme is demonstrated in the field trial of multi-vendor optical transport networks.In addition,simulation experiments are carried out to evaluate the performance of the proposed scheme.Simulation results show that the scheme can dynamically adjust the bandwidth based on traffic variation.Meanwhile,more bandwidth savings and lower packet loss rate can be achieved with a smaller value of step size and adjustment period.Lastly,for the network leasing demand of Virtual Network Operators(VNOs),this paper proposes a Network on Demand(NoD)solution for VNOs by means of software-defined hierarchical control architecture.This scheme consists of two parts:node mapping and link mapping.Network operators can complete all the procedures through visual interface,which greatly simplifies the procedure of network provisioning.Based on hierarchical control architecture,the solution is first verified in field trial networks with commercial OTN equipment from three vendors.Field trial results show that with the proposed solution,NoD service can be deployed via online web portals,which significantly improves the response to customer needs.