Research Of Virtualization Of Multi-Dimensions Optical Network Based On Software Defined Networking

The capacity requirements of optical transport networks are dramatically increasing due to the rapidly growing of bandwidth-hungry applications,like cloud computing,ultra-high definition video(UHDV),etc.The wavelength division multiplexing(WDM)technology based on traditional single mode fiber(SMF)can not meet the future demand of optical network transmission.The elastic optical network(EON)based on optical orthogonal frequency division multiplexing(O-OFDM)improves the spectrum efficiency of the optical network.And space division multiplexing(SDM)using multi-core fiber(MCF)or few mode fiber(FMF)is used to increase the transmission capacity,thus forming a multi-dimensional optical network(MDON).Moreover,with the increasing of data centers(DCs),the application of MDON to realize interconnection of DCs becomes the development trend of optical networks among DCs.Compared with the traditional WDM optical network,the MDON has more complex resource hierarchy and more difficult control.The traditional distributed control mechanism cannot realize the control of MDON.Software defined networking(SDN)can improve the scalability of network through the separation of control plane and data plane,and centralized control can improve network control efficiency.In this paper,the application of SDN concept in MDON is designed to realize the control architecture of SD-MDON.On this basis,virtual resources are formed through the abstraction of the underlying physical resources of the MDON,and these virtual resources are allocated to the virtual networks(VNs)to realize the virtualization of MDONs.In this paper,a virtual optical network(VON)mapping mechanism considering the mode-dependent loss(MDL)is studied.At the same time,in the scenario where the MDON is applied to the interconnection between DCs,the collaborative virtualization mechanism of the IT resources of DCs and transmission resources of the inter-DC MDON is considered.Based on this,the topology-aware virtual network mapping mechanism and the crosstalk-aware virtual network mapping mechanism and other related technologies are studied for the problem of virtual network embedding(VNE)in inter-DC MDONs.This paper mainly includes the following:(1)MDON has greatly improved the network transmission capacity and the virtualization of MDON is also one of the effective means to achieve efficient use of optical network resources.However,the MDON has a complex resource hierarchy and is more difficult to control.How to achieve efficient control and virtualization of MDONs is a prominent problem.This paper studies the MDON control architecture based on SDN and proposes a resource abstraction and virtualization mechanism in a SD-MDON.Based on this,a VON service mechanism is introduced,and reasonably distribute optical switching and optical transmission resources according to the requirements of different VON users.Thus different VONs share physical layer resources of optical network.The VON service mechanism based on the SD-MDON simplifies network management and control,provides on-demand VON services for users,and improves the efficiency of network resource utilization.(2)In a MDON using strongly-coupled FMFs,MDL and other physical layer impairments(PLIs)have a great influence on the end-to-end transmission quality of the optical channel.Aiming at the impact of physical damage on network transmission quality,this paper proposes a PLI-aware VON mapping method.Based on the study of the MDL evaluation model for the strongly-coupled FMFs,an end-to-end transmission quality assessment method for MDON based on FMFs is established.Based on this,a PLI-aware VON mapping algorithm is proposed.In the VON mapping process,especially the virtual link mapping process,the impact of MDL on the virtual link transmission quality is considered,and the mapping policy is dynamically adjusted to allocate suitable resources for the VONs.The mapping algorithm can reduce the blocking probability of the network under the premise of guaranteeing the transmission quality of the VONs.(3)In an inter-DC MDON,it is necessary to allocate suitable calculate storage resources of DCs for a virtual DC(VDC)and provide appropriate bandwidth of optical network for data transmission between nodes of the VDC.This is an important research content of inter-DC MDON virtualization.This paper proposes a topology-aware VN service mechanism.The DCs and MDON are virtualized based on software-defined platform.Based on this,the topology-aware VNE mechanism is introduced.At the same time,node and link cooperative mapping mechanism is introduced to implement efficient VNE in the inter-DC MDON.Through the cooperation of DC resources and optical network transmission resources,the utilization efficiency of network resources is improved and the blocking probability of the network is reduced.(4)Weakly-coupled FMFs are used for the interconnection of distributed DCs in metropolitan areas,which increases the transmission capacity of inter-DC optical network.However,the crosstalk(XT)between the mode groups(MGs)in the weakly-coupled FMF will affect the transmission quality of the optical channel.This paper proposes a XT-aware VNE mechanism for VN service quality assurance requirements.Based on the inter-mode XT evaluation model,a method for evaluating the transmission quality of MDON using FMFs is proposed.Based on this,a XT-aware virtual node mapping mechanism and a XT-aware virtual link mapping mechanism are proposed.The organic combination of the two mapping mechanisms can alleviate network resource conflicts.Through the pre-sequencing of nodes and links and the pre-checking and feedback mechanism of transmission quality in the mapping process,XT-aware coordination of IT resources in DCs and optical network transmission resources is achieved.The proposed XT-aware VNE can improve the blocking probability performance and resource utilization.