链路可靠性感知的差异保护虚拟光网络映射

针对弹性光网络的多链路故障影响虚拟光网络映射性能问题,提出一种链路可靠性感知的差异保护虚拟光网络映射（RA-DPVONE）方法.根据光节点的资源特性与相邻链路故障概率,该方法设计了光节点重要性评估准则和优先映射方法.根据候选光路上的可用频谱资源和链路故障概率,设计虚拟链路映射的工作光路和保护光路的链路代价更新公式,仅为不满足可靠性需求的虚拟链路映射资源共享保护光路.仿真结果表明,所提方法能降低网络的带宽阻塞率,提高虚拟网络请求接受率和弹性光网络的频谱资源利用率.     

核心链路感知的可生存虚拟网络链路保护方法

针对现有可生存虚拟网络链路保护方法无差别对待所有虚拟链路、备份资源消耗多且故障后网络恢复时延长的问题,该文提出一种核心链路感知的可生存虚拟网络链路保护(CLA-SVNLP)方法。首先,综合考虑虚拟链路动态和静态两方面因素构建虚拟链路核心度度量模型,依据虚拟网络生存性需求,对核心度较高的虚拟链路进行备份保护;其次,将p圈引入可生存虚拟网络链路保护,依据虚拟网络特点构建p圈,为核心虚拟链路提供1:N保护,即每条核心虚拟链路平均消耗1/N条的备份链路带宽资源以减少备份链路资源消耗,并将单物理链路保护问题转化为多个p圈内的单虚拟链路保护问题;最后网络编码技术与p圈结合,将备份链路对核心虚拟链路提供的1:N保护转化为1+N保护,避免了故障后定位、检测及数据重传。仿真结果表明,该方法提高了备份资源利用率且缩短了故障后的网络恢复时延。     

无线传感器网络可靠性建模方法

无线传感器网络部署设计的基础就是可靠性,因此,对无线传感器网络可靠性研究已经成为全世界在这个领域中研究的一个重点内容。无线传感器网络可靠性研究的一个有效方法就是建立数学模型。为了能够更好地进行无线传感器网络可靠性的建模,本文先介绍了无线传感器网络结构和节点模型,然后主要对无线传感器网络可靠性建模方法进行分析,提出了K-可靠性模型,并对无线传感器网络系统设计时参考依据进行简单说明。经过实践证明,无线传感器网络的可靠性完全能够通过K-可靠性模型进行测量。     

基于身份加密的无线传感器网络密钥分配方法

由于无线传感器网络在电源、计算能力和内存容量等方面的局限性,传统的网络密钥分配和管理方法已不适用.本文从基于身份密钥体系出发,提出了一种适用于无线传感器网络的密钥预分配方法.首先简要介绍了身份密钥体系,特别是Boneh-Franklin算法,然后基于身份密钥系统和Diffie-Hellman算法,给出我们的密钥分配方法,并从方法的复杂性、安全性、健壮性和内存需求等方面,与随机算法等进行了分析比较,结果表明我们的算法在这些方面有一定的优势.最后我们讨论了可进一步研究的内容.     

基于自适应网络编码的异构无线链路并发传输控制方法研究

随着高清视频直播、虚拟现实等高速率业务不断兴起,单一的网络很难满足用户的业务需求。利用多种异构链路实现并发传输,可以有效聚合带宽资源,提高服务质量。但是,在异构无线网络中,由于链路状况复杂多变,多条链路质量不一,现有的多路径并发传输算法并不能自适应地根据复杂的网络状况做出最优的决策。该文提出了一种自适应网络编码的多路径并发传输控制算法,引入Asynchronous Advantage Actor-Critic(A3C)强化学习,通过自适应的网络编码,根据当前网络状况智能地选择编码分组大小和冗余大小,从而解决数据包的乱序问题。仿真结果表明,该算法能够提高10%左右的传输速率,提升了用户体验。     

增强型的无线Mesh网络信道分配方法

为更可靠地实行无线mesh网络的资源分配,将干扰模型引入mesh网络的节点流量模型中,提出改进型的基于流量感知的固定C-HYA信道分配方法,采用一种更贪婪的算法规避波纹效应,降低网络干扰。之后对算法进行实现仿真,建立相应网络拓扑结构,对在mesh网络中采用传统算法及改进算法对抗波纹效应及信道干扰的情况进行了对比分析。     

基于链路优先的快速协同虚拟网络映射算法

在网络虚拟化环境中,为了减少链路映射成本和提高收益,提出了一种链路优先的协同映射算法。该算法交替映射链路和节点,并使用贪心思想优先将带宽资源需求较大的虚拟链路映射到跳数较少的物理路径上,最终达到降低虚拟网络平均消耗和提高虚拟网络接受率的目的。仿真结果表明,与已有算法相比,所提算法节约了链路映射的成本,提高了虚拟网络接受率和物理网络收益,算法运行时间也有效缩短。     

无线ATM网络的逻辑链路控制技术

无线ＡＴＭ网络中，在信元进入ＡＴＭ网络层前，须通过逻辑链路控制（ＬＬＣ）层来消除无线信道的影响。本文对使用不同数据包长度和不同ＡＲＱ技术的ＬＬＣ方案进行了比较，并折中考虑了实现的复杂程度与所获得的性能，得出在不同的条件下应使用的数据包长度。本文还仿真了在瑞利衰落环境采用传统ＡＲＱ和码组合ＡＲＱ技术时系统的性能，结果表明码组合ＡＲＱ为一种简单而有效的方法。     

无线网状网射频链路的信道分配算法

研究了无线网状网络节点的接口异构对网络容量的影响.提出了一种新颖的以射频链路为信道分配对象的接口和信道联合分配的分布式贪婪最大算法.该算法以队列长度为权的射频链路吞吐量之和最大为目标,寻找自适应于网络拓扑和流量变化的分布式接口与信道联合分配方案.算法分析指出本算法与非接口异构的Dist. Greedy算法的时间复杂度相当,NS2仿真结果表明网络容量有明显提升.     

基于图论的无线传感器网络并行禁忌搜索信道分配方法

Wireless sensor networks are suffering from serious frequency interference. In this paper, we propose a channel assignment algorithm based on graph theory in wireless sensor networks. We first model the conflict infection graph for channel assignment with the goal of global optimization minimizing the total interferences in wireless sensor networks. The channel assignment problem is equivalent to the generalized graph coloring problem which is a NP complete problem. We further present a meta heuristic Wireless Sensor Network Parallel Tabu Search (WSN PTS) algorithm, which can optimize global networks with small numbers of iterations. The results from a simulation experiment reveal that the novel algorithm can effectively solve the channel assignment problem.     

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。     

应用粒子群优化的绿色虚拟网络映射算法

绿色网络是近年来网络技术研究的热点,以节能为优化目标的虚拟网络映射算法成为基于网络虚拟化技术中资源分配研究的重点.提出了应用粒子群优化的绿色虚拟网络映射算法,重定义粒子群优化算法中的参数和粒子进化行为,以关闭底层网络节点和链路数量最多为适应度函数,在较低的算法复杂度条件下,获得绿色虚拟网络映射的最优解.仿真结果表明,与对比算法相比,静态环境下所提算法的运行时间大幅度降低;动态环境下所提算法的节点关闭率、链路关闭率、虚拟网络请求接受率均有所提升,算法运行时间也大大缩短.     

虚拟网络映射问题研究综述

对虚拟网络映射问题的相关研究工作进行了充分调研,对现有的研究成果进行了深入分析,并且指出了已有研究工作中关键技术的优缺点。最后讨论了可以进一步研究的方向,为虚拟网络映射问题的研究提供参考。     

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.     

A unified enhanced particle swarm optimization‐based virtual network embedding algorithm

Virtual network (VN) embedding is a major challenge in network virtualization. In this paper, we aim to increase the acceptance ratio of VNs and the revenue of infrastructure providers by optimizing VN embedding costs. We first establish two models for VN embedding: an integer linear programming model for a substrate network that does not support path splitting and a mixed integer programming model when path splitting is supported. Then we propose a unified enhanced particle swarm optimization‐based VN embedding algorithm, called VNE‐UEPSO, to solve these two models irrespective of the support for path splitting. In VNE‐UEPSO, the parameters and operations of the particles are well redefined according to the VN embedding context. To reduce the time complexity of the link mapping stage, we use shortest path algorithm for link mapping when path splitting is unsupported and propose greedy k‐shortest paths algorithm for the other case. Furthermore, a large to large and small to small preferred node mapping strategy is proposed to achieve better convergence and load balance of the substrate network. The simulation results show that our algorithm significantly outperforms previous approaches in terms of the VN acceptance ratio and long‐term average revenue. Copyright © 2012 John Wiley & Sons, Ltd.     

VNE-AFS：基于人工鱼群的网络虚拟化映射算法

虚拟网络资源映射是云计算研究领域的一个难点问题。以降低底层网络映射开销为目标,提出一种基于人工鱼群的网络虚拟化映射算法VNE-AFS。根据虚拟网络请求对底层网络节点和链路的约束关系建立二进制组合优化模型,并利用人工鱼群算法实现虚拟网络资源向底层网络资源的近似最优映射。实验结果表明,与现有的虚拟网络映射算法相比,该算法有效地降低了底层网络的开销和求解时间,提高了虚拟网络映射的成功率、平均收益和资源利用率。     

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.     

Research of embedding algorithm for wireless network virtualization

Wireless network virtualization has become one of the promising techniques in fifth generation mobile networks (5G),and the virtual network embedding plays a very important role.A model was formulated to describe the problem and a wireless virtual network embedding algorithm based on joint bandwidth and power allocation (WVNEA-JBP) was put forward,which selected the suitable node and path to serve the data transmission from virtual networks.In order to minimize the overhead while satisfy the higher capacity request,this algorithm considered the impact of interference of wireless links and supports path splitting.A case study was introduced to show how WVNEA-JBP to work.Furthermore,simulation results show that WVNEA-JBP is able to accomplish the efficient utilization of network resources and improve the accept rate of virtual network requests.     

分布式环境中基于协商的虚拟网映射算法

网络虚拟化技术可以在共享的底层物理网络上为用户同时提供多种可定制的服务网络。目前的虚拟网映射算法比较依赖于集中式的管理节点,使其在可靠性和适用范围等方面存在诸多问题。为此,提出了一种分布式环境下的虚拟网映射算法,该算法通过多个节点之间的相互协商来完成虚拟网的映射,并且在降低通信开销和缩短虚拟链路的路径长度方面进行了相应改进。实验结果表明,该算法与同类型算法相比,在资源利用率和通信开销方面具有一定的优越性。