Research On Bandwidth Resource Optimization Of Multi-dimensional Multi-Domain Optical Network Based On Software-defined Network

With the emergence of 5G,flow media,virtual reality,autonomous driving,and other new applications,end-users have put forward higher requirements on the bandwidth,latency,and signal flexibility of optical fiber networks.Optical network not only provides large bandwidth to guarantee information transmission but also needs to improve the bandwidth flexibility to increase the bandwidth efficiency.Now the optical network is categorized into the access network,Metropolitan Area Network(MAN),core network,and data center network.The access network technology has advanced to 50G/100G Passive Optical Network(PON).How to improve the flexibility of bandwidth allocation of PON to provide high-quality services has become the focus of current research.The data rate of MAN has reached to single-carrier 100 G at 100 kilometers.How to increase the flexibility of reconfiguration to complete the millisecond optical path reconstruction is still the focus and urgent issue of MAN.In the Data Center Network(DCN),facing the challenges brought by DCN's large scale,high energy consumption,and broad bandwidth,how to improve the DCN network flexible configuration and realize all-optical switching is one of the dominant topics in the future optical network.The emergence of the Software-Defined Network(SDN)has brought a new opportunity for the development of the optical network.The separation of control plane and data plane has dramatically improved the efficiency of network control.The concept of the Software-Defined Optical Network(SDON)is introduced into the optical network,and SDON has become a hot topic in the research of optical networks and has been widely concerned.However,there are still weaknesses in the development of SDN technology for the optical network.Based on the software-defined optical network,this thesis increases the flexibility of the optical network by SDN and then realizes the optimization of bandwidth resource management in various fields of the optical network.The Dynamic Wavelength-Bandwidth Allocation algorithm(DWBA)of the access network,Routing and Spectrum Allocation(RSA)algorithm,optical packet contention resolution scheme of optical switches,and load balancing algorithm of the DCN are studied in the thesis.The main works and innovation of the thesis are as follows:1.DWBA based on SDN in the access networkThis work studies the joint scheduling of wavelength and time slot in WDM/TDM-PON.A dynamic multi sub-PON architecture is designed to achieve wavelength scheduling,and a DWBA is proposed to allocate time slots and wavelengths efficiently.The proposed method allocates the timeslots and wavelengths in two-dimension bandwidth and supports the service classification to guarantee the QoS of high-level service.In this method,the timeslots can be allocated by Optical Line Terminal(OLT),whereas the wavelengths are allocated by the SDN controller to increase the flexibility of the bandwidth resource.The algorithm is studied by simulation and experiment.2.RSA algorithm based on ant colony optimization in the software-defined Elastic Optical Networks(EON)The thesis studies the RSA algorithm based on EON,proposes a multi-plane virtual topology model and proposes an RSA scheme based on spectrum consistency and ant colony optimization.Based on the multi-plane virtual topology model and statistical method of spectrum consistency,the proposed algorithm is compared with the existing algorithms in simulations.The simulation results show that the proposed algorithm can effectively reduce the blocking rate of the optical path requests by 5%,improve the link utilization rate,and reduce the generation of spectrum fragments.3.Packet contention resolution in DCN based on software-defined fast optical switchesIn this thesis,optical packet contention resolution and load balancing in DCN based on fast optical switching and flow control are studied.A hybrid polling contention resolution scheme based on SDN was proposed.The proposed algorithm is studied for OPSquare DCN by simulations and experiments.The results show that the proposed hybrid polling contention resolution scheme can effectively reduce packet loss rate,improve throughput,and reduce average latency.An SDN-enabled load-balancing algorithm is proposed in the thesis.The proposed algorithm is compared with the existing schemes.The results show that the proposed algorithm can improve throughput and reduce the packet loss rate.