运营商网络中面向时延优化的服务功能链迁移重配置策略

在引入网络功能虚拟化（NFV）后，运营商能基于通用的计算和网络平台提供更具弹性的服务.本文研究基于NFV的运营商网络中的服务功能链（SFC）的迁移重配置问题.首先分析了业务流的动态性导致的运营商网络中资源利用率下降和负载不均的问题，然后在将计算资源、网络资源和业务流端到端限制等条件纳入考虑的基础上，建立了面向业务流服务时延优化的数学模型，并证明了SFC迁移重配置问题的NP性.进一步基于遗传算法提出了一种易于部署的启发式SFC迁移重配置策略.通过详细的对比实验表明算法在端到端时延、链路带宽资源占用率和通用服务器资源占用率等关键指标上优于其它方案12.3%、10.9%和15.8%以上.这进一步说明所提出方案通过对运营商网络资源的合理调配，在保证业务流服务质量的同时有效改善了资源利用效率.

Delay Optimization Oriented Service Function Chain Migration and Re-deployment in Operator Network

With the introduction of network functional virtualization (NFV),operators can provide more flexible services based on general computing and network platforms.This paper investigates the problem of migration and re-deployment of service function chain (SFC) in NFV based operator network.Firstly,this paper analyzes the problem of resource under-utilization and load unbalance in the operator network caused by the dynamic of the flow.Then,based on the consideration of the conditions such as computing resources,network resources and end-to-end restrictions,the mathematical model towards the service delay optimization is formulated,and the NP property of SFC migration and re-deployment problem is proved.Furthermore,a heuristic SFC migration and re-deployment policy is proposed based on genetic algorithm.In-depth experimental result demonstrates that the proposed solution is superior to other solutions in terms of end-to-end delay,the utilization ratio of link bandwidth resource and the utilization ratio of general server by 12.3%,10.9%,and 15.8%.The results further shows that the resource utilization is effectively improved in the case of guaranteeing the quality of service for flow,through the reasonable deployment of operator network resources.