Study Of Dynamic Virtual Network Mapping Algorithm In Elastic Optical Networks

With the incessant expansion of the Internet scale,the problem of network architecture ossification becomes more and more serious which hinders the further development of the Internet.Network virtualization is recognized as the effective technology to overcome the ossification problem on current networks.In addition,network traffic presents explosive growth which drives the increase of the demand for network bandwidths.Due to the fixed channel intervals,traditional wavelength division multiplexing optical network results in the waste of bandwidth resources and lacks flexibility in resource allocations.The emergence of elastic optical network makes up for the shortage of the WDM optical network.It allocates spectrum resources dynamically according to requirements of users and actual traffics.So,elastic optical networks can effectively support the development of the optical networks virtualization.The virtual network mapping is one of the key problems of the network virtualization.The physical resources can be shared by multiple users according the virtual network mapping.In addition,the resource requirements of existing applications are more dynamic than before,they need real-time resource allocations.The static virtual network mapping method has been difficult to meet its requirements.In order to improve the utilization of the physical resources and reduce mapping consumptions of virtual networks,this paper studied the dynamic virtual network mapping problem in elastic optical networks.The main contents are as follows:(1)This paper focuses on the dynamic virtual network mapping problem in elastic optical networks.Firstly,this paper analyzes physical networks,virtual networks and virtual network mapping constraints.Based on these,this paper constructs a mathematical model for the dynamic virtual network mapping.The model is the theoretical base for following researches.(2)Taking into account the mapping constraints of elastic optical networks,and aiming at reducing the mapping consumption of virtual networks,this paper proposes an algorithm called node first virtual networks mapping algorithm.This algorithm is based on virtual nodes and links coordinated mapping.The proposed algorithm can improve the acceptance ratio and reduce consumption of virtual network requests at the same time.(3)Considering the dynamic resource requirement of virtual network requests in the period of service and the influence of modulation formats on virtual links mapping,this paper proposes a cost effective virtual network mapping algorithm with dynamic resources reconfigurations.In order to providing enough physical resources,the proposed algorithm reconfigures allocated physical resources and migrates virtual nodes while resource requirements of virtual network requests increase.