Research On Embedding Algorithm Based On Cluster In Elastic Optical Network

With the rapid development of network technology and the explosive growth of Internet services,the impact of the Internet’s rigidity problem has become more and more serious.To solve this problem,the Network Virtualization,which allows multiple independent virtual networks to be deployed simultaneously on a physical network,has become the focus of attention.This thesis has designed an efficient new virtual optical network embedding algorithm which aims to improve the utilization efficiency of the physical network resources.First of all,this thesis proposes a virtual optical network embedding algorithm based on fuzzy clustering(FC-VNE).To make sure that the fuzzy clustering algorithm can be applied to the virtual optical network embedding algorithm,the fuzzy clustering algorithm has been appropriately modified.According to the algorithm,in the initial stage of embedding,the physical network will be divided into several clusters,and the physical nodes are close together in each cluster.Then,the virtual network will be mapped into a single cluster,to ensure that the virtual nodes are densely distributed in the physical network.In more specific,the algorithm adopts the node and link cooperative embedding mechanism.In the node resource calculation formula,the capacity of the node and the bandwidth availability of the surrounding links are comprehensively considered,which can help to sort nodes reasonably and develop better resource allocation strategies.In the link embedding stage,the KSP algorithm is used for routing path selection.Finally,to better guide the final spectrum allocated,the FC-VNE algorithm compares the changes of spectrum resources on the link path before and after the allocation of spectrum allocation,which can help to reduce the generation of spectrum fragments and increase the probability of fragment reuse.All the mechanism that the algorithm adopts can improve the carrying capacity of the physical network and the resource utilization,reduce the blocking rate.Secondly,in order to solve the problem that the proposed algorithm does not consider the sensitive factors of fuzzy clustering algorithm and the usage of the underlying physical network resources,this thesis propose three improved algorithms for different problems.The first improved algorithm is the Fuzzy Clustering Virtual Optical Network Embedding algorithm based on Adaptive initial Core Distance(ACDFC-VNE).It’s known that the fuzzy clustering algorithm is sensitive to the selection of initial clustering cores.Then the ACDFC-VNE algorithm limits the minimum distance between all initial cores when selecting,so as to avoid the problem that the algorithm tends to converge to local extremes during the division process,and improve the diversity of clustering schemes to ensure load balance on the physical network.The second improved algorithm is the Fuzzy Clustering Virtual Optical Network Embedding algorithm based on Path Spectrum Resource Perception(PSRPFC-VNE)This algorithm takes into account the use of resources in the network during the process of clustering.It fully considers the spectrum usage of the path between nodes when calculating the node membership,so that the resources between the nodes in the divided cluster are relatively abundant,which can reduce the congestion of network requests due to resource shortages.The third improved algorithm is the Fuzzy Clustering Virtual Optical Network Embedding algorithm based on Clustering Fitness(CFFC-VNE).The previous algorithms didn’t consider the suitability of the topology within the cluster and the virtual optical network request.Then the CFFC-VNE proposed the concept and calculation formula of clustering suitability,and adopt the posteriori determination method to analyze the suitability of multiple different clusters and virtual optical networks,so as to determine the final selection of clusters for mapping.The improvement of the CFFC-VNE can further reduce network fragmentation and balance the goal of using limited resources in the underlying network.The fourth improved algorithm is the Fuzzy Clustering Virtual Optical Network Embedding algorithm based on Adaptive Clustering Scale(ACSFC-VNE).The main goal of this algorithm is to adaptively adjust the number of member nodes in the cluster according to proportion of nodes with high resource occupancy in the cluster,thereby reducing the mapping failure and the increase in blocking rate due to insufficient resources in the cluster.At the same time,the compactness of the distribution of cluster member nodes is ensures as much as possible when resources are abundant.Finally,through simulation,the performance advantages of all the new algorithms in network blocking rate and link utilization are verified.