基于流量演化感知的服务功能链在线弹性编排策略

随着网络功能虚拟化（NFV）的引入，运营商能够提供更为灵活的网络服务.然而现有服务功能链（SFC）编排局限于静态反应式策略，业务流量发生变化时网络资源供应量难以匹配负载需求，虚拟网络功能（VNF）频繁部署与迁移，运营开销增大.针对上述问题，该文提出一种基于流量演化感知的服务功能链在线弹性编排策略（OEOP），该策略将在线学习引入到SFC流量演化感知的过程，预先确定细粒度的VNF弹性需求.此外，以实时更新的SFC路径与节点负载两因子为导向，完成新增VNF的在线弹性部署，代替VNF迁移应对系统负载变化.仿真表明，该策略明显增强了虚拟资源供应量与负载需求的匹配特性，VNF吞吐量利用率提高10.2%~24.8%，运营开销平均降低26.7%.

Online Elastic Orchestration Policy of Service Function Chain Based on Flow Evolution Perception

With the introduction of network function virtualization (NFV),operators can provide more flexible network service.However,most existing orchestration schemes of service function chain (SFC) are limited to the static or reactive policy where the virtual network functions (VNFs) need to be deployed or migrated frequently,and will easily lead to the mismatch of service supplement and high operational expenditure under time-varying workload.This paper proposes an online elastic orchestration policy (OEOP) based on the evolution perception of flow rate to solve the above mentioned problem.OEOP introduces online learning into the evolution perception of flow rate,which helps to predetermine the fine-grained VNF scaling demands.In addition,the online elastic deployment is achieved according to the real-time update information of SFC paths and the load of nodes.The newly deployed VNF instances can respond to the time-varying workload by taking place of the mission of VNF migration.The simulation results demonstrate that OEOP can significantly enhance the matching between virtual resource supply and workload demand.The throughput of VNF is improved by 10.2%~24.8%,and the operational expenditure can be reduced by 26.7% on average compared with other solutions.