共查询到19条相似文献,搜索用时 171 毫秒
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基于DPI技术的校园网络带宽管理 总被引:5,自引:0,他引:5
面对校园网用户和业务流量的不断增长,对网络带宽资源需求也越来越大,但是各种网络应用无序地抢占有限的带宽,必然导致网络运行效率的降低.文中为了提高网络运行效率,比较三种主流带宽管理技术,结合学校实际,在校园网出口部署带宽管理设备,通过分析校园网络出口流量,对出口网络流量带宽进行有效的管理,实施网络带宽管理策略,保证关键的科研教学网络需求,控制非关键应用对带宽的耗费,节约出口带宽资源,提高网络使用性能,保障了网络安全运行. 相似文献
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传统的数据中心网络难以为指定业务的网络带宽需求提供保障.基于SDN(Software Defined Network)的网络带宽保障系统通过在Floodlight控制器中开发网络带宽保障服务,并采用MVC(Model View Controller)模式设计出一个客户端软件,能够实现用户对网络状态的实时监控和对带宽保障策略的灵活调度.在Mininet搭建的虚拟网络环境中进行测试的结果显示,该系统能够实时监控网络状态、灵活调度带宽保障策略,进而准确有效地保障网络中指定业务的带宽需求. 相似文献
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随着数据中心网络规模的迅速增长,网络带宽利用率低下导致的网络拥塞问题日益突出,通过负载均衡提高数据中心网络链路带宽利用率和吞吐量成为了研究热点.如何结合流量特征、链路状态和应用需求进行流量的合理调度,是实现网络链路负载均衡的关键.针对数据中心突发性强、带宽占用率高的大象流调度问题,提出一种面向SDN数据中心网络最大概率路径流量调度算法,算法首先计算出满足待调度流带宽需求所有路径,然后计算流带宽与路径最小链路带宽之间的带宽比,结合所有路径的带宽比为每一条路径计算路径概率,最后利用概率机制选择路径.算法不仅考虑了流带宽需求和链路带宽使用情况,而且全局地考虑了流调度和链路带宽碎片问题.实验结果表明,最大概率路径调度算法能够有效地缓解网络拥塞,提高带宽利用率和吞吐量,减少网络延迟,从而提高数据中心的整体网络性能和服务质量. 相似文献
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在高带宽时延乘积网络中,现有TCP协议由于其使用的拥塞控制机制使得数据流长时间以低速率发送数据,不能有效利用网络带宽,造成带宽利用率随着带宽的增大而下降。对高带宽时延乘积网络中TCP的性能进行仿真,结果表明在该网络环境中使用TCP传输数据不能有效利用网络带宽。最后详细分析拥塞控制机制造成TCP使用带宽利用率低的原因。 相似文献
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提出一种新型基于通信数据分组到达时间的拥塞避免算法,以数据分组的到达时间差异来判断网络带宽的拥塞情况,为发送端速率控制提供拥塞控制的依据.在模型控制中建立VTP虚拟传输协议,实现拥塞避免和实时传输协议之间解耦合.该算法通过对拥塞控制建模和优化,较好地解决了针对ad hoc网络的实时流媒体传输的带宽适应性难题. 相似文献
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一种自适应的视频流化前向纠错算法 总被引:13,自引:0,他引:13
网络视频应用经常会受到数据包丢失或错误以及网络带宽资源不足的干扰.相关研究表明:在多数情况下,动态变化的网络带宽和丢包率是影响视频流化质量的关键因素.因此,为了保证视频质量,可以采用前向纠错(forward error correction,简称FEC)编码来提高视频数据传输的可靠性;同时,为了适应网络状态的变化,发送端可以调节视频数据的发送速率,并在视频源数据与FEC数据之间合理分配网络传输带宽.首先通过对视频流结构的分析,在充分考虑帧之间的依赖关系和帧类型的基础上提出了一种帧的解码模型.在此基础上,建立了用于在视频源数据和FEC数据之间分配网络带宽资源的优化算法.实验表明,该模型可以有效地适应网络状态的变化,并通过优化分配网络带宽资源来使接收端获得最大的可播放帧率. 相似文献
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Zuxin Li Wanliang Wang Yunliang Jiang 《International Journal of Control, Automation and Systems》2009,7(2):289-296
There is an unavoidable tradeoff between the control performance and the quality of service in networked control systems with
resource constraints. To address the impact of network resources availability on requirement of bandwidth (RoB) and quality
of control (QoC), an intelligent control approach to dynamic bandwidth management, namely fuzzy bandwidth management, is proposed
based on fuzzy logic control technique. In order to guarantee the system’s stability, the lower and upper bound of the assignable
bandwidth are evaluated in terms of linear matrix inequalities and the resource constraints, respectively. In addition, the
normalizable criterions of QoC and RoB are also defined, which can estimate the performance of the whole networked control
systems. Preliminary simulations are carried out to highlight the merits of the proposed approach. It is argued that the proposed
approach can save significant bandwidth and simultaneously improve overall control performance in comparison with the fixed
bandwidth allocation and optimal bandwidth allocation.
Recommended by Editorial Board member Young Il Lee under the direction of Editor Young-Hoon Joo. This work was supported by
the National Natural Science Foundation of China under Grants 60573123, 60872057, and by the Zhejiang Provincial Natural Science
Foundation of China under grant Y107293.
Zuxin Li received the B.Eng. degree from Zhejiang University of Technology, China, in 1995, the M.Sc. (Eng.) degree from Yunnan Univer-sity,
China, in 2002, and the Ph.D. degree from Zhejiang University of Technology, China, in 2008. He is currently an Associate
Professor in the School of Information Engineering, Huzhou Teachers College, China. His research interests include networked
control systems and intelligent control.
Wanliang Wang received the Ph.D. degree from Tongji University, China, in 2001. He is currently a Professor in Zhejiang University of Technology,
China. His research interests include computer control, computer net, CMIS, and production scheduling.
Yunliang Jiang received the B.S. degree in Mathematics from Zhejiang Normal University in 1989, and the M.E. and Ph.D. degrees in Computer
Science and Technology from Zhejiang University, Hangzhou, China. He is currently a Professor in the School of Information
Engineering, Huzhou Teachers College, China. His research interests include information fusion, artificial intelligence, and
geographic information system. 相似文献
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本文针对双通道约束下的线性时不变网络控制系统的随机信号跟踪性能极限问题进行了研究.网络通信包含通信噪声和通信带宽两种信道因素.被控系统考虑是非最小相位和不稳定系统,并且系统包含多个不同的非最小相位零点和多个不同的不稳定极点.对上行通道和下行通道都存在通信带宽约束及高斯白噪声影响的情形,从频域角度,通过采用双自由度控制器和尤拉参数化方法,获得了此类网络控制系统的最优可达的跟踪性能.研究结果表明网络控制系统的跟踪性能极限完全由被控对象的结构特征(非最小相位零点、不稳定极点以及被控对象的系统增益),参考输入信号和网络特性(高斯白噪声的统计特征、通信信道带宽)所决定.最后,仿真结果检证了所得结果的正确性. 相似文献
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多回路网络化控制系统级联反馈调度 总被引:1,自引:0,他引:1
针对动态环境下的多回路网络化控制系统,本文基于反馈控制与网络调度协同设计的思想,提出一种级联反馈调度策略.以优化系统整体控制性能为目标,根据可用带宽资源的动态变化,对控制回路采样周期进行在线调节,将截止期错过率控制在期望的较低水平,并对可用带宽进行优化分配.仿真实验结果表明,相对于传统设计方法,该方法能够明显改善整体控制性能. 相似文献
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Xi‐Sheng Zhan Zhi‐Hong Guan Xian‐He Zhang Fu‐Shun Yuan 《Asian journal of control》2014,16(4):1155-1163
The best tracking problem for a single‐input‐single‐output (SISO) networked control system with communication constraints is studied in this paper. The tracking performance is measured by the energy of the error signal between the output of the plant and the reference signal. The communication constraints under consideration are finite bandwidth and networked induced‐delay. Explicit expressions of the minimal tracking error have been obtained for networked control systems with or without communication constraints. It is shown that the best tracking performance dependents on the nonminimum phase zeros, and unstable poles of the given plant, as well as the bandwidth and networked induced‐delay. It is also shown that, if the constraints of the communication channel do not exist, the best tracking performance reduces to the existing tracking performance of the control system without communication constraints. The result shows how the bandwidth and networked induced‐delay of a communication channel may fundamentally constrain a control system's tracking capability. Some typical examples are given to illustrate the theoretical results. 相似文献
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针对无线传感器网络(WSNs)中目标跟踪性能与传感器能量消耗难以平衡问题,提出一种信念重用的WSNs能量高效跟踪算法。使用部分可观察马尔可夫决策过程(POMDPs)对动态不确定环境下的WSNs进行建模,将跟踪性能与能量消耗平衡优化问题转化为POMDPs最优值函数求解过程;采用最大报酬值启发式查找方法获得跟踪性能的逼近最优值;采用信念重用方法避免重复获取信念,有效降低传感器通信带来的能量消耗。实验结果表明:信念重用算法能够有效优化跟踪性能与能量消耗之间的平衡,达到以较低的能量消耗获得较高跟踪性能的目的。 相似文献
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This paper presents an optimal tracking performance of multiple‐input multiple‐output (MIMO) networked control systems (NCSs) with quantization and bandwidth constraints. In this study, we simultaneously consider the encoding‐decoding, quantization and bandwidth of communication channel. The optimal tracking performance of NCSs is obtained by spectral factorization technique and partial fraction. The obtained results demonstrate that the optimal tracking performance is influenced by the nonminimum phase zeros and unstable poles as well as their directions for a given plant. In addition, it is shown that characteristics of reference signal, encoding‐decoding, quantization, and bandwidth of communication channel are also closely related to tracking performance. Finally, the efficiency of proposed tracking performance is verified by typical examples. 相似文献
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随着云计算需求与服务器数量的不断增长,数据中心网络(data center network,DCN)面临可扩展性、低成本、低能耗、高带宽等一系列挑战。提出了一种基于阵列波导光栅路由器(arrayed waveguide grating router,AWGR)的光电混合数据中心网络架构。该混合架构由AWGR提供大容量光波长路由,由电分组交换机提供突发分组交换,同时满足大象流量和老鼠流量的需求。AWGR是无源光器件,将有效降低网络能耗,提高网络可靠性,与光电路交换机相比,可降低配置时间延迟。分析了在架顶交换机上分别采用全固定波长激光器(方案1)、混合固定波长激光器和波长可调谐激光器(方案2)、全波长可调谐激光器作为光源(方案3)的3种架构方案。对3种架构方案的成本和能耗进行了数值分析和计算,同时对网络性能进行了理论分析与仿真。成本和能耗数值分析结果显示:3种架构方案的成本与能耗随着服务器数量的增加不断增长,方案3增长的速度最快,方案1增长的速度最慢,方案2介于两者之间。网络性能仿真结果显示:在不同网络负载情况下,方案2架构的网络吞吐量和波长请求阻塞率与方案3接近,远高于方案1,因此混合固定波长激光器与波长可调谐激光器的方案2具备较好的性价比。 相似文献