Research On Four-layer Multigranularity Optical Cross-connect Network System Based On T-SDN

The three-layer Multi-Granularity Optical Cross-Connect(MG-OXC)structure based on optical fiber,wavelength band,and wavelength has been widely used in network construction,but the wavelength utilization rate is low,the waveband is limited by wavelength continuity.And a three-layer structure based on Optical Code Division Multiplex(OCDM)could improve wavelength utilization,but the number of ports used has increased significantly.In response to the above problems,this article adopts a four-layer MG-OXC structure with fiber,wavelength band,wavelength and optical code,and research on three aspects of hardware structure,control level and resource allocation.First,in terms of hardware,the specific structure of the four-layer MG-OXC is introduced.On the one hand,optical code granularity is applied to improve wavelength utilization,on the other hand,the Code Group Routing Entity(CGRE)structure is used to reduce the port usage during service transmission.Secondly,at the control plane,this article focuses on the structure and communication process of Hierarchical Path Computation Element(H-PCE),and proposes a two-way backup PCE structure based on TransportSoftware Defined Networking(T-SDN)and used for H-PCE,to reduce network complexity and the risk of paralysis.Then,the multi-granularity resource allocation process under the four-layer MG-OXC structure is studied,including wavelength allocation,wavelength bundling,and optical code resource allocation.This paper proposes a maximum common path bundling algorithm based on Waveband Switching(WBS),and on the basis of CGRE optical code bundling,a wavelength selection strategy for Code Group(CG)services is proposed,to reduce the number of unbinding and binding times and the number of ports in service transmission,and improve business transmission efficiency.After that,summarize the resource allocation process of the four-layer MG-OXC structure.Finally,the port numbers of the four-layer MG-OXC structure and the two types of three-layer structure are compared,analyze the positive effect of WBS module in reducing port usage in the four-layer structure.Then,comparing the number of ports in the two fourlayer structures that using Optical Code Division Multiplex(OCDM)and CGRE,found that the optical code bundling of CGRE can effectively reduce the number of ports.Analyze the CGRE packet loss rate and find that the reasonable bundling of optical codes can reduce the packet loss rate.At the end of the article,it is verified that the increase of the optical code granularity can improve the wavelength utilization.