Research On Key Technologies Of Network Function Virtualization For Telecom Operators

In recent years,the network service demand in telecommunication network has become more and more sophisticated and diversified,and the rise and application of the technology of Network Function Virtualization(NFV)is becoming the bright light to lead operators out of this dilemma.NFV is a new concept promoted by the European Telecommunications Standards Institute(ETSI)to simplify the deployment and management of network services using virtualization and cloud technologies.NFV technology replaces proprietary hardware with software middleware,which enables network functions such as firewalls,load balancers,and intrusion detection systems to deploy on commodity servers flexibly.However,while this technology brings flexibility and scalability,it also leads to an increase in the overall energy consumption of the network and a decline in the service reliability.Therefore,this thesis has conducted in-depth research on two key technologies:energy saving and service reliability guarantee in telecommunication networks.First,Chapter 3 studies the combination optimization of Virtual Network Function(VNF)deployment and Service Function Chain(SFC)mapping in the telecommunication network with energy saving as the goal.This chapter formulates the problem as an integer linear programming model and proposes energy consumption model for the two major sources of energy consumption in the network: physical link for transimittion traffic and server for hosting VNFs.Finally,based on the Markov approximation technology,we design an approximation algorithm to complete the VNF deployment and traffic routing decisions in polynomial time and optimize the network energy consumption.The simulation results show that,compared with greedy algorithm and multi-stage deployment algorithm,the proposed algorithm generates less energy consumption in polynomial time.Then,Chapter 4 takes into account the factors of energy efficiency and service reliability in the telecommunications network.This chapter presents a novel NFV architecture with green(energy saving)orchestration capabilities.This architecture relies on two major functional modules: energy-efficient resource allocation and service reliability assurance.This study improves service reliability by adding one or serveral protection paths to the SFC to meet the 99.999% reliability requirements of the telecommunications network.However,adding protection paths requires more network equipment resources to support,ultimately resulting in increased energy consumption.In order to optimize energy consumption in this case,we design a Lagrangian relaxation technique based heuristic SFC mapping algorithm.The algorithm leverages the Lagrangian relaxation technique to calculate available protection path repeatedly until the overall reliability of the SFC finally meets the requirement.The algorithm proves that in the simulation results,it will generate less energy consumption while meeting the end-to-end service reliability requirement.