Research On SDN-Based Virtual Network Mapping Algorithm

Network virtualization builds multiple virtual networks on physical network and provides them to multiple tenants.The centralized control idea of software-defined network provides a simpler and more flexible approach to implement network virtualization.One of the key problems facing network virtualization in traditional network or SDN is virtual network mapping problem or virtual network embedding problem.Many researches on virtual network mapping problem ignore the virtual network topology and the remaining resources of the physical nodes.In addition,there are few researches focus on survivable virtual network mapping problem and most researches ignore the importance of backup resources sharing,therefore we propose a virtual network mapping algorithm under SDN and a survivable virtual network mapping algorithm to survive a single substrate link failure to solve the problems above.The main contents of this paper are as follows:(1)We create models for the underlying physical network and virtual network requests,analyze the resource relationship in the mapping process and the resource requirements of virtual nodes and links,and propose the evaluation standard of virtual network mapping.(2)This paper proposes a virtual network mapping algorithm based on node resources level.We establish the mapping module for the virtual nodes by the resources requirements of them and construct the mapping module tree according to the virtual network topology to keep the topology properties of the virtual nodes.In addition,the node resources level model is proposed to solve the problem of node resources consumption differences and improve the ability of substrate nodes to accept subsequent virtual nodes.We propose VNE-NRL based on the above strategies at last.Simulation results show that VNE-NRL can effectively improve the revenue cost ratio and acceptance ratio.(3)We propose a survivable virtual network embedding algorithm based on backup resources sharing driven.This algorithm constructs and simplifies the backup topology of the virtual network and applies the backup resources sharing mechanism when mapping backup links.In addition,to increase the amount of shared resourcesand reduce the cost of backup topology,this algorithm uses ant colony algorithm and combines backup resources sharing driven and puts forward the adaptive pheromone impact factor to solve the limitations of fixed weight.Besides,we propose a survivable virtual network mapping algorithm SVNE-NRL based on VNE-NRL to increase the usability of it.Simulation results show that SVNE-NRL has higher revenue cost ratio while SVNE-BRSD has better overall performance.