Research Of Three-Dimensional Protection Technologies For Optical Networks

Optical networks are faced with the challenge of ultra-large-scale and ultra-high-speed development.Ultra-large-scale is reflected in tens of thousands of nodes to achieve intelligent networking,and ultra-high-speed transmission of wavelength channels in optical fibers up to Tbit/s.At the same time,along with the large-scale increase of optical network capacity and the node throughput capacity of Pbit/s,these factors make the failure of optical fiber links cause a large number of service interruptions,and their survivability issues become increasingly complex.With the expansion of the optical network scale and the increasing complexity of the network topology,the possibility of random concurrent multiple link failures in the optical network is greatly increased,and the survivability technology of optical fiber link failures in optical networks is mainly focused on single link failures.Although existing survivability technologies have been studied for the recovery of multiple fault protections,they cannot effectively solve the problem of random concurrent multiple link failures in optical networks.In order to solve the above problems and satisfy the survivability requirements of optical networks under multiple faults,this paper mainly focuses on the research of protection technologies for random concurrent multiple link failures,and carries out theoretical derivation,construction of mathematical models,and verification of simulation experiments.The main innovative results we obtained are presented in this paper and three aspects are included:Firstly,a theoretical analysis model of the logical redundancy and spectral capacity efficiency of the Flexible Bandwidth Optical Networks is established.In the case of a single link failure and multiple link failures,the lower bound and the minimum value on logical redundancy of the Flexible Bandwidth Optical Networks,the upper bound and the maximum value on spectral capacity efficiency of the Flexible Bandwidth Optical Networks is deduced respectively,and under the condition that the network protection resources are sufficient(100%against link failures),proves that the lower bound of the logical redundancy of the network and its minimum value are only determined by the number of random concurrent link failures and the average node degree of the network.The upper bound of the spectrum capacity efficiency of the network and its maximum value are only determined by the number of nodes in the fully connected graph of the network and the number of random concurrent link failures.Secondly,aiming at the characteristics of high topology connectivity and relatively limited spectrum resources in optical networks,we propose a construction algorithm APSC for the design of three-dimensional protection structures based on preconfigured k-edge-connected structures(p-kecs)and resource allocation strategy are proposed.We also analyze the logical redundancy and the spectrum capacity efficiency of the three-dimensional protection structures based on p-kecs under multiple-link failures.Theoretical results show that the three-dimensional protection structures based on p-kecs is the optimal protection structure in flexible bandwidth optical networks under multiple link failures.The greater the number of concurrent faulty links based on the k-edge connectivity three-dimensional protection structure protection,the greater the logical redundancy,and it needs more protection spectrum resources to protect the faulty services.The larger the average node degree based on the k-edge connectivity three-dimensional protection structure is,the smaller its logical redundancy is,and more work services in the network can share its protection spectrum resources.The simulation results show that the three-dimensional protection structures based on p-kecs can effectively reduce the network logical redundancy and improve the network spectrum capacity efficiency.Thirdly,we propose a construction algorithm NEMK for the design of three-dimensional protection structures based on p-kecs,the integer linear programming(ILP)model,the topological score,the a priori efficiency,and the efficiency ratio of the three-dimensional protection structures based on p-kecs under multiple-link failures in Wavelength Division Multiplexing(WDM)networks.At the same time,the concept of three-dimensional,regularization,and extensibility is applied to fault tolerance and protection of large-capacity optical networks.A polyhedron-based three-dimensional protection structure construction method,resource allocation and multiple fault protection methods are proposed.The topological score and the a priori efficiency of the three-dimensional protection structures are decided by the topology only and are the preselection metrics of the three-dimensional protection structures.The higher value of topological score and a priori efficiency of the three-dimensional protection structures means the more straddling links of the protection structures.The efficiency ratio of the three-dimensional protection structures is determined by both the topology and the working capacity that are actually protected by the three-dimensional protection structures.The higher efficiency ratio of the three-dimensional protection structures means the higher utilization ratio of the protection resource of the protection structures.Hence it represents the posteriori efficiency of the three-dimensional protection structures.