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输入排队Crossbar交换是高性能交换设备最为常用而关键的技术之一.本文建立了IQ-Crossbar架构下的矩阵模型,给出了IQ-Crossbar的状态矩阵、队长矩阵、到达矩阵和匹配矩阵的数学定义,并通过分析IQ-Crossbar的信元排队机理,提出和证明了队长矩阵迭代定理和状态矩阵迭代定理.该矩阵模型为分析IQ-Crossbar架构下的调度算法提供了理论依据.基于所建立的矩阵模型,在分析现有LQF调度算法优缺点的基础上,本文提出了一种新的调度策略MM-LQF,该策略的运算效率是LQF的3.72倍,支持的端口门限速率是LQF的2.35倍,在贝努利均匀流量重载条件下平均时延是LQF的1/2;在贝努利Diagonal流量条件下吞吐率为100%. 相似文献
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针对LTE网络测试仪的测试需求,本文对IP流量生成技术进行了研究,提出了一种双模式IP流量发生器的设计方案,介绍了总体平台的设计架构及其工作原理,性能模式下流量控制的算法,仿真模式下利用读写索引进行数据边发送、边更新的软件控制方法。测试应用表明,该IP流量发生器能定量、定速发送指定IP数据分组,且能模拟高速网络流量,具有良好的性能,能较好地满足IP数据采集与仿真测试的需求。 相似文献
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IP路由表查找是实现高性能路由器的主要瓶颈。根据IP业务流量分布特性,在现有的路由表查找技术的基础上,提出了基于流量分布的高速路由表查找算法。 相似文献
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带VOQ的输入队列交换网络中的分组调度算法研究 总被引:1,自引:0,他引:1
交换技术已经成为高速路由器的核心技术。本文基于目前高速交换技术所采用的主要体系结构,带有虚拟输出缓冲队列(VOQ)的输入队列交换结构,分析已经存在的各种调度算法的性能,并设计基于遗传算法的调度策略,提供IP数据网络的QoS对吞吐量和抖动的保障。 相似文献
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网络流量预测在网络拥塞控制及资源分配中起着至关重要的作用。对于具有自相似性的网络业务流量,由于其存在较强突发,传统预测方法的预测精度普遍较低。本文针对存在高突发的网络流量数据,提出了一种基于数据分离的流量预测方法。在预测步骤前,本方法首先通过控制图将网络流量中难以预测的突发流量进行有效的分离,从而得到突发流量和非突发流量两部分数据。之后分别采用人工神经网络和自适应模板匹配方法实现对非突发流量和突发流量的预测。最后通过对两部分预测结果的合并得到最终的预测结果。基于实际流量数据的实验结果表明:相较于传统流量预测方法,本文所提出的方法具有更高的流量预测精度。 相似文献
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自相似网络通信量模型研究综述 总被引:7,自引:0,他引:7
越来越多的研究表明网络通信量不是Markov过程,而是在任意时间尺度上都具有突发特性,即自相似特性。描述网络通信量的数学模型主要有自相似和长相关结构。网络的某些参数服从重尾分布,从而导致网络通信量时间尺度上的突发特性。该文分析了传统网络通信量模型和性能分析的弊端,描述了新型网络通信量模型应该具有的基本特征。本文重点研究了网络自相似通信量相关的ON/OFF模型、用户访问概率模型和网络流量闭环模型,讨论了相关的研究方向,并总结了在研究网络通信量模型的过程中应该注意的原则和问题。 相似文献
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Lu Guanghong 《电子科学学刊(英文版)》1998,15(4):339-346
This paper introduces two source models: MAP(Markovian arrival process) model for the traffic with correlation and burst, e.g., voice, video, etc. and PAP(Poisson arrival process) model for the traffic with non-correlation, such as data, etc. Then a movable boundary bandwidth access policy is chosen.Basing on above model, the performance measures, e.g., mean waiting time and loss probability,especially the queue length time distribution are obtained. Finally, a number of numerical results are provided and shown through simulation. 相似文献
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Reinaldo Vallejos Alejandra Zapata Marco Aravena 《Photonic Network Communications》2007,13(2):217-226
A novel, accurate, numerically stable and fast mathematical method for network-wide blocking probability evaluation of end-to-end
optical burst switching (OBS) networks with heterogeneous link capacity under non-uniform traffic is proposed. Unlike most
of previous works, which have used the Poisson model for the burst traffic, this paper considers a non-uniform ON–OFF model
being a more realistic choice for OBS networks. Compared with simulation, the method was proved to be very accurate and much
faster (up to four orders of magnitude faster than simulation in the studied cases). These features make the proposed method
very useful for network analysis, especially for large size networks where simulation time can be prohibitively high. 相似文献
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使用泊松业务流模型对光突发交换网络进行性能分析不能准确地反映网络状态。该文从理论上对突发包长度进行了推导,对基于时间门限汇聚机制下突发包数据流自相似程度进行了计算机仿真测量,并利用自相似业务流模型对光突发交换网络中比较常用的LAUC和LAUC-VF调度算法进行了性能仿真。仿真结果表明:基于时间门限的汇聚机制能够有效地降低数据流自相似程度,数据流的自相似特性对LAUC算法的影响并不非常明显,但对LAUC-VF算法的性能则产生了比较严重的影响,其突发包丢失率较泊松流平均增加了近3个百分点。 相似文献
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How to reconstruct end-to-end traffic based on time-frequency analysis and artificial neural network
Dingde Jiang Zuyao Zhao Zhengzheng Xu Chunping Yao Hongwei Xu 《AEUE-International Journal of Electronics and Communications》2014,68(10):915-925
End-to-end traffic, which describes the inherent characteristics and end-to-end behaviors of communication networks, is the crucial input parameter of network management and network traffic engineering. This paper proposes a new reconstruction algorithm to develop the research on reconstruction of end-to-end traffic in large-scale communication networks. We firstly conduct the time-frequency analysis on end-to-end traffic, and then localize its features to gain its time-frequency properties before decomposing it into the low-frequency and high-frequency components. We find that if decomposing appropriately, the low-frequency component of end-to-end traffic can accurately reflect its change trend, while its high-frequency component can well show the burst and fluctuation nature. This motivates us to find a reasonable time-frequency decomposition strategy to extract the low-frequency and high-frequency components of end-to-end traffic. Moreover, this further inspires us to use the regressive model to model the low-frequency part, exploit artificial neural network to characterize the high-frequency component, and then combine these two parts according to the regressive model and artificial neural network to precisely reconstruct end-to-end traffic. Simulation results show that in contrast to previous methods our algorithm is much more effective and promising. 相似文献
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A crucial issue in optical burst switching (OBS) networks is burst loss caused by resource contention. As a result, many methods
are currently being proposed to reduce burst loss rate. These methods can be summed up into two categories: burst scheduling
algorithms and contention resolutions. Both categories of methods can reduce burst loss rate to a certain degree. However,
to make OBS to become a viable solution, the burst loss rate needs to be further reduced. Furthermore, almost all methods
ignore the fact that an unfortunately scheduled, locally generated single-hop burst could block a number of future incoming
transit bursts, though the burst just travels to its next downstream node. This phenomenon becomes more evident when links
are heavily loaded in mesh OBS networks. To eliminate contention caused by single-hop traffic completely, this paper proposes
a novel transfer mode called packet calking by differentiating between single-hop traffic from multihop traffic for OBS networks.
An analysis model is developed to evaluate the performance of packet calking. Theoretical results are validated through extensive
simulations in both ring and mesh networks. These results show that packet calking outperforms the transfer mode without packet
calking in terms of burst loss rate and link utilization. 相似文献
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本文针对英特网上的一个常用协议-远程登录(TELNET)协议分析了它的客户端数据包产生的时间间隔分布,发现泊松模型的指数分布不能很好地刻画它的特性。本文依据Tcplib提供的经验分布曲线,认为Pareto分布在很大时间范围内能较好地描述TELNET的客户端流量特性,并对其突发序列的特性进行了分析。本文最后指出在描述网络流量时自相似模型要比泊松模型有效和精确得多,并给出了Pareto分布在建立自相似 相似文献
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This paper considers the characteristics of Wireless Application Protocol (WAP) traffic. We start by constructing a WAP traffic model by analysing the behaviour of users accessing public WAP sites via a monitoring system. A wide range of different traffic scenarios were considered, but most of these scenarios resolve to one of two basic types. The paper then uses this traffic model to consider the effects of large quantities of WAP traffic on the core network. One traffic characteristic which is of particular interest in network dimensioning is the degree of self-similarity, so the paper looks at the characteristics of aggregated traffic with WAP, Web and packet speech components to estimate its self-similarity. The results indicate that, while WAP traffic alone does not exhibit a significant degree of self-similarity, a combined load from various traffic sources retains almost the same degree of self-similarity as the most self-similar individual source. 相似文献