关于数据中心间弹性光网络中虚拟网络功能配置的问题建模及优化算法

Modeling and Optimization Algorithm for Virtual Network Function Deployment in Inter-Datacenter Elastic Optical Networks

网络功能虚拟化技术能有效地降低网络投资成本,且能够提高网络服务的灵活性。而虚拟网络功能配置是网络功能虚拟化中需要解决的一个关键问题。为解决弹性光网络中虚拟网络功能服务链的选路和虚拟网络功能配置问题,建立了一个以网络中最大占用频隙号、网络中占用频隙数,以及配置的虚拟网络功能数目最小化为目标的全局约束优化模型。将虚拟网络功能划分为具有依赖关系的虚拟网络功能和不相互依赖的虚拟网络功能两种类型。为高效地求解所建立的模型,设计了具有高效编码方法、交叉算子,以及变异算子的遗传算法。在不同的网络拓扑和参数下进行了仿真实验,实验结果表明所设计的算法能够得到比对比算法更优的虚拟网络功能服务链的选路方案和虚拟网络功能配置方案。

The network function virtualization(NFV)technology can significantly reduce the capital expenditure and improve the flexibility of network serves.The virtual network function(VNF)deployment problem is one of the key problems that should be addressed in NFV.A global constrained optimization model is established to minimize the maximum index of the used frequency slots,the number of used frequency slots,and the number of initialized VNFs,thereby solving the issues of routing and VNF deployment for service chains in inter-datacenter elastic optical networks.VNFs are divided into VNFs with and without dependency,respectively.To ensure the effectiveness of the proposed model,an efficient genetic algorithm based on highly efficient encoding,crossover operators,and mutation operators is designed.Several simulation experiments are conducted using different network topographies with different parameters.The experimental results denote that the proposed algorithm can obtain improved routing and deployment schemes for service chains in the VNF when compared with other algorithms.