Research On Survivability Based Routing And Spectrum Assignment Scheme In Space-Division Multiplexing Elastic Optical Networks

Elastic optical networks(EON)have a fine granularity of spectrum resource allocation,effectively overcoming the problems of inflexible service bearing and low spectrum resource utilisation in traditional WDM networks.Multi-core fiber(MCF)based Space-Division Multiplexing Elastic Optical Network(SDM-EON)expands the spatial dimension on the basis of elastic optical network and significantly increases the transmission capacity of optical network while introducing inter-core crosstalk.However,while SDM-EON increases the transmission capacity,if the underlying bearer optical network is interrupted due to various disasters,there will be even greater losses and incalculable consequences.Therefore,there is an urgent need to design an efficient resource allocation strategy with guaranteed survivability in space division multiplexing elastic optical networks.The theoretical analysis and numerical simulations are used to study the resource allocation problem in the space division multiplexing elastic optical network considering the survivability mechanism.The paper firstly analyses the basic principles,basic architecture and key technologies of elastic optical networks,introduces the RSA problem in elastic optical networks,and focuses on the survivability technology in elastic optical networks as well as the inter-core crosstalk problem and RCSA problem in space-division multiplexing elastic optical networks.To address the resource allocation problem related to survivability in space-division multiplexing elastic optical networks,the paper measures the utilisation rate of protection resources in the network through spare capacity redundancy and proposes a survivability RCSA algorithm based on a protection resource saving strategy on this basis.To address the problem that different services have different survivability requirements,three protection strategies,namely no protection,shared backup path protection and dedicated protection,are used to provide protection for services and meet the survivability requirements of network services.The algorithm is designed with link weight values for spare capacity redundancy reduction,which is used to dynamically update the spare capacity redundancy in the network and to downgrade the protection policy according to the average link weight value in the protection path when allocating protection frequency slot resources for the services.The simulation results show that the improved algorithm can effectively reduce the spare capacity redundancy and network blocking probability compared with the traditional DPP+FF algorithm and HP-RCSA algorithm under different topology environments.For the structural characteristics of multi-core fibers and inter-core crosstalk problems,the thesis research proposes a survivability RCSA algorithm based on shared risk groups in multi-core fibers.The concept of shared risk core group is proposed for the failure characteristics of multi-core fibers,which can effectively reduce the use of protection frequency slot resources by allocating the working and protection frequency slots of the services in different shared risk core groups in the same path.The service allocation priority is also proposed,and the allocation scheme that triggers the least crosstalk between cores is selected for resource allocation when allocating working and protection slot resources.Simulation results show that the improved algorithm can effectively reduce the bandwidth blocking probability and inter-core crosstalk compared with the traditional DPP+FF algorithm and SRCGR algorithm under different topology environments.