一种基于Viterbi算法的虚拟网络功能自适应部署方法

为了应对移动数据流量的爆炸性增长,5G移动通信网将引入新型的架构设计。软件定义网络和网络功能虚拟化是网络转型的关键技术,将驱动移动通信网络架构的创新,服务链虚拟网络功能的部署是网络虚拟化研究中亟待解决的问题。该文针对已有部署方法未考虑服务链中虚拟网络功能间顺序约束和移动业务特点的问题,提出一种基于Viterbi算法的虚拟网络功能自适应部署方法。该方法实时感知底层节点的资源变化并动态调整拓扑结构,采用隐马尔科夫模型描述满足资源约束的可用的底层网络节点拓扑信息,基于Viterbi算法在候选节点中选择时延最短的服务路径。实验表明,与其它的虚拟网络功能部署方法相比,该方法降低了服务链的服务处理时间,并提高了服务链的请求接受率和底层资源的成本效率。     

一种基于主-备份节点同步映射的VNF热备份机制

网络功能虚拟化实现了网络功能与专属硬件平台的分离,虚拟网络功能（Virtual Network Function,VNF）通过动态组合形成服务功能链,实现同一硬件平台部署不同的功能服务。针对软件定义网络功能服务可靠性和物理网络资源效率问题,提出了一种基于主备份节点同步映射的VNF节点热备份机制。首先,选择满足节点资源约束的物理节点为主备份节点候选映射对;然后,选择满足带宽约束的最短物理链路为服务路径,实现节点与链路资源总开销的优化。实验结果表明,与传统的备份机制相比,该方法能够满足电信级高可靠性的服务需求,降低了VNF节点备份资源总开销,提高了服务请求的接受率和底层物理网络资源的利用率。     

一种采用NFV架构的服务功能链动态编排与部署

随着虚拟化技术的出现,网络功能虚拟化(Network Function Virtualization,NFV) 和软件定义网络(Software Defined Networking,SDN) 技术使网络功能从硬件中抽象出来并可运行在虚拟机上,将虚拟网络功能映射部署到物理网络上,为用户提供定制化服务。服务功能链(Service Function Chaining,SFC) 由一组虚拟网络功能组成,目前其部署的一个关键问题是如何在保证为用户提供相应服务的同时降低网络资源消耗和负载压力。为此,首先介绍了一种可用于服务功能链编排的NFV 架构,并对基于SRv6 技术的SFC 编排过程进行说明;然后提出了一种有效的SFC动态编排算法——第一步使用广度优先搜索遍历网络并找到部署服务链的最短物理路径,第二步使用蚁群优化算法生成最优部署方案。仿真结果表明,该方案能够有效减轻网络负载,同时平均降低端到端延迟22%,减少带宽资源消耗18%,优化部署成功率23%。     

网络虚拟化中动态资源分配算法研究

针对网络虚拟化中资源分配问题,提出一种动态的资源分配算法。算法根据物理节点平均负载差异度,结合当前物理网络容忍的节点负载差异动态地进行虚拟节点迁移,并通过综合影响因子为虚拟节点选择合适的目标宿主,减少虚拟节点迁移对物理链路带宽和虚拟链路时延的影响。仿真实验表明,该算法能使物理节点上的负载分布均衡,同时对时延和带宽的影响较小。     

面向多节点故障的生存性虚拟网络映射方法

针对网络虚拟化环境中虚拟网络的生存性问题,提出一种面向多节点故障的生存性虚拟网络映射方法。该方法预先在物理网络中按比例留出备份资源并根据拓扑属性构造节点的候选集合,在发生节点故障后从故障节点的候选集合中选取重映射目标并动态分配预留的备用资源来恢复受到影响的虚拟网络,提高长期运营利润。仿真实验在多节点故障模型下从适用性、稳定性及性能方面验证了该方法的有效性。     

一种基于匹配博弈的服务链协同映射方法

针对软件定义网络(SDN)/网络功能虚拟化(NFV)环境下服务链映射难以兼顾效率与物理资源利用率的问题,该文提出一种基于匹配博弈的服务链协同映射方法。首先,以最大化网络资源效用为目标,建立服务链映射模型MUSCM;然后,分虚拟网络功能(VNF)部署和组链两个部分解决服务链映射问题,VNF部署部分,设计基于多对一匹配博弈理论的算法协同服务链和服务节点双方互相进行选择,有效提升了服务链的映射效率和物理资源的利用率,在此基础上,设计基于分段路由策略的算法实现各VNF实例间的流量牵引以完成VNF组链,有效降低了链路传输时延。实验结果表明,与经典算法相比,该算法在保证映射请求接受率的同时,有效降低了服务链的平均传输延时,提升了系统的物理资源利用率。     

基于信任评估的虚拟网故障诊断算法

网络虚拟化环境的新特点(网络拓扑动态变化、动态症状和故障关系、管理域独立和信息不准确性)对故障诊断提出了新的要求,提出一种改进的针对网络虚拟化环境下虚拟网和底层网故障诊断模型和诊断算法,通过虚拟网信任评估算法来提高故障诊断的准确率、降低误报率.仿真研究结果表明,在大规模和噪声大的虚拟网络环境中,提出的故障诊断算法取得了较好的诊断效果.     

基于改进灰狼优化算法的服务功能链映射算法

随着工业互联网、车联网、元宇宙等新型互联网应用的兴起，网络的低时延、可靠性、安全性、确定性等方面的需求正面临严峻挑战。采用网络功能虚拟化技术在虚拟网络部署过程中，存在服务功能链映射效率低与部署资源开销大等问题，联合考虑节点激活成本、实例化开销，以最小化平均部署网络成本为优化目标建立了整数线性规划模型，提出基于改进灰狼优化算法的服务功能链映射（improved grey wolf optimization based service function chain mapping，IMGWO-SFCM）算法。该算法在标准灰狼优化算法基础上添加了基于无环K最短路径（K shortest path，KSP）问题算法的映射方案搜索、映射方案编码以及基于反向学习与非线性收敛改进三大策略，较好地平衡了其全局搜索及局部搜索能力，实现服务功能链映射方案的快速确定。仿真结果显示，该算法在保证更高的服务功能链请求接受率下，相较于对比算法降低了11.86%的平均部署网络成本。     

面向差异化业务请求的虚拟网络映射算法

网络虚拟化是克服当前网络僵化的重要方法,而资源分配是网络虚拟化实现的核心.为了解决业务差异性需求导致的物理网络资源分布不均,造成虚拟网络接受率下降的问题,提出面向差异化业务请求的虚拟网络映射算法.该算法首先定义反应节点和所连接链路资源比的节点饱和度,依此将虚拟节点映射在节点饱和度最接近虚拟网络请求的物理节点上,最后基于所映射的物理节点和节点饱和度约束,将虚拟链路映射在由物理链路组成的路径上.仿真结果表明该算法能够满足不同业务的差异化请求,具有较高的资源利用率和虚拟网络接受率.     

信任感知的安全虚拟网络映射算法

针对网络虚拟化技术带来的新的安全威胁,将信任关系和信任度引入到虚拟网络资源分配中,量化分析了网络虚拟化环境中的安全问题,构建了安全虚拟网络映射的数学模型,并在映射过程中考虑节点的局部和全局重要性,采用逼近理想排序法方法对节点进行多属性重要度排序,提出了一种信任感知的安全虚拟网络映射算法。仿真结果表明,该算法在满足虚拟网络请求可信需求的条件下,获得了较好的映射成功率、映射收益和资源利用率。     

Dynamic recovery for survivable virtual network embedding

Network virtualization is a promising way to overcome the current ossification of the Intemet. It is essential challenge to find effective, efficient and robust embedding algorithms for recovering virtual network. The virtual network mapping algorithm based on integer programming which was proposed months ago. But it did consider the faults of physical network resources, which is so called survivable virtual network embedding （VNE） problem. Previous strategies for enabling survivability in network virtualization focused on providing protection for the physical network or enhancing the virtual networks by providing backup physical resources in advance, and treated all the physical failures as link failures. In the article, a dynamic recovery method is proposed to solve the survivable virtual network embedding problem based on the integer programming VNE algorithm. The dynamic recovery method doesn＇t need to backup physical resources and it makes more substrate resources which can be used in the embedding. The dynamic recovery process will be activated only when physical failures occur. Different algorithms are used to recovery node and link failures. Simulations show that the method helps to recover almost all of physical failures by finding the substitute nodes and paths, and its performance is very close to that of pure VNE method without considering physical failures.     

Optimal mapping of virtual networks with hidden hops

Network virtualization has emerged as a solution for the Internet inability to address the required challenges caused by the lack of coordination among Internet service providers for the deployment of new services. The allocation of resources is one of the main problems in network virtualization, mainly in the mapping of virtual nodes and links to specific substrate nodes and paths, also known as the virtual network embedding problem. This paper proposes an algorithm based on optimization theory, to map the virtual links and nodes requiring a specific demand, looking for the maximization of the spare bandwidth and spare CPU in the substrate network, taking into account the CPU demanded by the hidden hops when a virtual link is mapped. The components of the virtual networks (nodes and links) that do not ask for an specific demand are then allocated following a fairness criteria.     

基于多商品流模型的虚拟链路映射

网络虚拟化是解决网络僵化问题和更好地共享底层网络资源的一种有效途径,虚拟网络映射是实施网络虚拟化的关键问题之～。虚拟网络映射包括节点映射和链路映射两个方面,其目标是为虚拟网络请求分配合适的底层网络节点和链路资源。阐述了底层网络支持路径分割时,如何基于多商品流模型实现VN链路映射。     

虚拟网络映射高效节能运输模型及算法

网络虚拟化使得智能能量感知网络部署成为可能,已有研究忽略了节点映射能耗最优化。本文把节点映射能耗优化问题转化为生产地与销售地之间物资运输代价最优化问题,建立高效节能节点映射运输模型。根据最大元素法,提出了混合一阶段与两阶段映射算法,在链路映射的约束下找到节点分配最小能耗代价最优解;利用主动休眠策略,提出了基于运输模型的主动休眠虚拟网络映射节能算法;利用节点可重复映射技术,提出了基于运输模型的节点可重复映射算法,进一步提高了底层网络资源休眠数量。仿真结果验证了本文所提算法能够显著降低系统能耗,适合大规模高效节能虚拟网络映射。     

Adaptive scheme based on status feedback for virtual network mapping

Network virtualization is considered as a powerful way to deploy different network architectures and protocols over a shared physical infrastructure.Virtual network(VN)embedding plays an important role in the network virtualization environment.Virtual network embedding is mainly about mapping virtual nodes and virtual links onto the physical network resources efficiently.However,load balancing of substrate network has not received much consideration.This paper proposes an adaptive virtual network mapping algorithm based on status feedback.The main contribution is to embed the virtual network requests according to the current load distribution of substrate network.This adaptive algorithm differentiates the residual bandwidth of substrate links and takes full advantage of the multi-path to improve the load balancing of the substrate network.Simulation experiments show that the proposed algorithm improves the load distribution of substrate network distinctly while reducing the average substrate link stress significantly.     

Quality of Service Modelling of Virtualized Wireless Networks: A Network Calculus Approach

Wireless network virtualization is an emerging technology that logically divides a wireless network element, such as a base station (BS), into multiple slices with each slice serving as a standalone virtual BS. In such a way, one physical mobile wireless network can be partitioned into multiple virtual networks each operating as an independent wireless network. Wireless virtual networks, as composed of these virtual BSs, need to provide quality of service (QoS) to mobile end user services. Key QoS parameters include buffer queue length, network delay and effective bandwidth, in particular their upper bound forms. This paper presents a QoS model for such a wireless virtual network addressing these parameters. This QoS model considers resources of both physical nodes and virtual nodes and provides a realistic modelling of the delay and bandwidth behaviours of wireless virtual networks. Network calculus (NC), which usually provides finer insight into a system, is utilized to fulfil the modelling task. The numerical results have shown the effectiveness of the proposed model. The model is useful for both off-line network planning and online network admission control.     

基于灾难预测多区域故障的虚拟光网络生存性映射

生存性虚拟光网络映射是提高光网络应对灾难故障的重要技术保障措施。为解决灾难性多区域故障导致弹性光网络的带宽容量损失问题,该文提出基于灾难预测故障模型的蚁群优化虚拟光网络映射 (DFM-ACO-VNM)算法。在该算法中,设计基于光节点资源和相邻链路的全局潜在故障概率的光节点排序映射准则,并设计启发式信息公式实现多区域故障下最小带宽容量损失的虚拟节点和虚拟链路协同映射。仿真结果表明,该文所提算法在多区域故障时能降低带宽容量损失,减少带宽阻塞率和提高频谱利用率。     

Embedding and reconfiguration algorithms for service aggregation in network virtualization

Network virtualization and transmission quality optimization are promising techniques for future Internet. Previous researches on virtual network embedding focused on efficient utilization of network resources. In this paper, we present a virtual network embedding scheme that aims at improving the effect of transmission quality optimization. In order to enable more service benefit from optimization, the embedding algorithm presented in this paper follows the service aggregation embedding principle. We also develop a reconfiguration algorithm based on service aggregation and load balance. Simulation experiments demonstrate that the proposed algorithms can achieve good performance on service aggregation as well as efficient resource utilization. Copyright © 2014 John Wiley & Sons, Ltd.