Research On Multi-fault Survival Virtual Network Embedding In Elastic Optical Networks

In recent years,with the rapid development of cloud computing,video on demand,high-definition television and the Internet of everything,the transmission capability of the existing communication backbone network has been greatly challenged.At the right time,optical networks,especially elastic optical networks based on orthogonal frequency division multiplexing can greatly improve the utilization of resources in the network with their fine-grained bandwidth allocation and flexible selection of bandwidth modulation levels.At the same time,in order to solve the problem of network rigidity,network virtualization is proposed as the key technology.It virtualizes the underlying network resources into virtual resource pools through network virtualization technology,which can support multiple heterogeneous networks to share infrastructure resources and greatly improve the utilization of resources.Among them,the most critical issue of virtual network technology is virtual network mapping.In addition,the optical fiber links in the network will cause certain probability of failure due to human damage,natural disasters or link aging and other factors,so that the virtual network service being transmitted in the network will fail,resulting in huge economic losses.Therefore,how to ensure the survival of virtual network and reasonable allocation of resources has a very important research significance.This paper studies survivable virtual network mapping and resource allocation strategy.The specific content of the thesis and innovative work are mainly the following aspects:First of all,in order to solve the problem of huge bandwidth capacity loss caused by multi-region disasters,we propose a virtual optical network mapping algorithm,called disaster fault model based on ant colony optimization of virtual network mapping algorithm.Based on the resource characteristics of the node and the global potential failure probability of its adjacent link,the proposed algorithm designed a node sort formula during the process of node mapping.In order to avoid the problem that the virtual link mapping path is too long due to the mapping of adjacent virtual nodes,a virtual node-link cooperative mapping is adopted.At the link mapping phase,considering the possible loss of bandwidth capacity caused by the mapping of newvirtual links to physical paths,a heuristic information is designed to ensure that the bandwidth loss of this physical link is minimal even if a failure occurs.The simulation results show that the proposed algorithm can achieve the lowest bandwidth capacity loss,and the bandwidth blocking rate is reduced and the spectrum utilization is improved.Secondly,aiming at the virtual network mapping problem under multi-link failure of the substrate elastic optical network,a reliability-based service-differentiated virtual optical network collaborative mapping strategy is proposed,and a virtual optical network service reliability evaluation theory model is established to evaluate Based on the reliability of the service and the actual reliability of the network,the reliability-aware service differentiation protection method is designed to ensure the reliable transmission of the virtual optical network service.And through the way of virtual node and link the collaborative mapping to map the virtual link in the most effective use of idle spectrum block on the physical path of shorten the virtual link mapping physical path length,at the same time,the separation of the work-protection first end last joint spectrum allocation method,reduces the fragments of the frequency spectrum after mapping to a physical path.Simulation results show that the proposed algorithm can improve the acceptance rate and spectrum resource utilization rate of the virtual optical network in multi-link fault environment,and well reduce the bandwidth blocking rate.