共查询到20条相似文献,搜索用时 171 毫秒
1.
2.
近年来,大量研究表明,网络业务流量呈现长相关、自相似的特性,采用ON/OFF源模型生成自相似流能够比较真实地反映现实网络中的业务流量。光突发包的汇聚算法是光突发交换的关键技术之一,利用ON/OFF模型生成的自相似流对几种典型的OBS汇聚算法进行研究。仿真表明,不同算法对自相似的影响不同。 相似文献
3.
自相似业务模型—通信网络突发业务建模的新方法 总被引:26,自引:3,他引:23
在研究通信网络的流量控制及网络性能时,业务源模型是一个十分重要的组成部分。传统的业务模型大多基于Poisson模型或其改进形式,假定业务突发长度呈负指数分布。近年来对大量的WAN、LAN、及VBR业务、ISDN中传输的业务等多种业务的测量表明:在这些业务中普遍存在着自相似性(或称为长相关性)。该性质显著影响宽带网的流量控制及排队分析,因而已经受到越来越多的关注。本文综述了近几年在自相似业务模型研究方面所取得的主要成果,包括自相似业务的数学描述、建模方法、排队分析等。 相似文献
4.
自相似网络业务流量的研究与实现 总被引:7,自引:0,他引:7
为了准确测试和评估网络交换设备及其调度算法的性能,一个能够真实反映实际网络业务流量特点的业务流量产生系统是十分必要的。近年来通过对大量网络业务流量的测量和分析,人们认识到网络业务流量呈现为长相关、自相似的特性,而非泊松过程。将这一特性和现有的业务流量描述模型相结合,利用具有重尾特性的概率分布函数:Pareto分布和截尾重尾分布,构造了在宏观上表现为自相似特性的业务流量模型。针对路由交换机构调度算法的性能测试的实际需要,建立了一个可用于软件测试的网络业务流量产生系统。 相似文献
5.
提出了一种适应于自相似业务环境的网络流量采集算法,该算法在多级过滤的基础上引入概率接纳机制。理论分析表明,该算法保留了多级过滤使用内存小的优点,同时又能反映自相似业务环境下业务流在多时间尺度上的突发性,提高了流量采集的准确性。 相似文献
6.
现代实际网络业务相比传统业务更为复杂,在各个时间尺度下表现出自相似的突发特性(相关函数上表现为长相关特性)。我们可以在线测量网络中的高速业务流,再根据实测时间序列数据,用RMD方法建立并分析高速业务流的自相似模型。RMD算法速度快,同时能很好的匹配业务流的自相似特性。 相似文献
7.
对广域网流量特性的深刻理解是研究和开发下一代网络体系结构的必要基础。文章采用小波技术对Internet流量的自相似和多重分形特性进行研究.同时通过对具有代表性的真实的广域网流量的小波系数、尺度系数、局部尺度指数以及多重分形能谱的分析来进一步细致刻画广域网流量的双重特征。 相似文献
8.
9.
本文首先介绍了自相似业务模型的特点并给出了它的数学定义,并在此基础上推导了突发业务在网络中的QoS指标中的信元丢失率与相关参娄的关系,说明采用自相似业务模型不但真实地反映了突发业务特性,而且用该模型也能正确地反映QoS指标。 相似文献
10.
11.
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
12.
《Networking, IEEE/ACM Transactions on》2009,17(1):120-129
13.
Admission control in asynchronous transfer mode (ATM) networks is considered. An ATM switch is modeled as a discrete-time single-server queue at which the following three different kinds of arrival processes are allowed to join together: arrivals of cells with a general interarrival time distribution; Bernoulli arrivals of cells in batches; and interrupted Poisson processes. An exact analysis is given to derive the waiting-time distributions and interdeparture-time distributions for arriving cells subject to admission control in ATM networks. The model is extended to approximately obtain the end-to-end delay distributions for the designated traffic stream. Such an analysis is important for voice or coded video because they require a playout mechanism at the destination. Since the analysis is approximate, the simulation results needed to assess its accuracy are provided. Numerical examples show how the traffic characteristics of the designated traffic stream are affected by the total traffic load at the switching node, the number of other bursty traffic sources, and the degree of burstiness of the traffic source itself 相似文献
14.
自相似业务下资源分配研究 总被引:2,自引:1,他引:1
重点研究了排队系统中自相似业务带宽分配和接纳控制.根据分形布朗运动包络过程推导出了有效带宽的计算公式,并且推导出了考虑信源内增益和信源间增益的接纳控制算法.通过仿真研究了有效带宽随缓存区、Hurst系数的变化关系,接纳域随缓存区、Hurst系数的变化关系.证明了基于FBM下的资源分配比传统的模型更有效. 相似文献
15.
The scheduling scheme in packet switching networks is one of the most critical features that can affect the performance of the network. Hence, many scheduling algorithms have been suggested and some indices, such as fairness and latency, have been proposed for the comparison of their performances. While the nature of Internet traffic is bursty, traditional scheduling algorithms try to smooth the traffic and serve the users based on this smoothed traffic. As a result, the fairness index mainly considers this smoothed traffic and the service rate as the main parameter to differentiate among different sessions or flows. This work uses burstiness as a differentiating factor to evaluate scheduling algorithms proposed in the literature. To achieve this goal, a new index that evaluates the performance of a scheduler with bursty traffic is introduced. Additionally, this paper introduces a new scheduler that not only uses arrival rates but also considers burstiness parameters in its scheduling algorithms. 相似文献
16.
Multiple-access interference processes are self-similar in multimedia CDMA cellular networks 总被引:1,自引:0,他引:1
Zhang J. Konstantopoulos T. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(3):1024-1038
We consider bursty data communications in code-division multiple-access (CDMA) cellular networks. The significant fluctuation of the cochannel multiple-access interference (MAI) in such systems makes it very challenging to carry out radio resource management. A main goal of this paper is to obtain a fundamental understanding of the temporal correlation structure of the MAI, which plays a crucial role in effective resource allocation. To this end, we take a cross-layer design approach, and characterize the stochastic MAI process while taking into account both the burstiness of data traffic and time-varying channel conditions. Our main results reveal that under standard assumptions on ON/OFF traffic flows and fading channels, the MAI process exhibits scale-invariant burstiness and is "self-similar" (with Hurst parameter 1/2相似文献
17.
18.
Recently, self-similar (or fractal) stochastic processes have been regarded as more accurate models of certain categories of traffic (e.g. LAN traffic) which will be transported in ATM networks. The authors propose a method for estimating the cell loss probability in an ATM multiplexer fed by a self-similar arrival process. The packet arrivals are generated by a fractional Brownian motion process and the service process is deterministic. The approach is based on theory for large deviations, and simulation tests show that it is more accurate than the existing approximation result 相似文献
19.
This paper quantitatively analyzes the queueing delay of the constant-bit-rate (CBR) traffic in a multiplexer, where the CBR traffic is mixed with the traffic of another session (interfering traffic) that has throughput and burstiness constraints. This paper focuses as a quality-of-service (QoS) measure on the fraction of the CBR traffic that fails to meet a certain delay requirement. Results include the worst-case QoS of CBR traffic as a function of the throughput and burstiness parameters imposed on the interfering traffic. Results of this paper can be applied to traffic management and call processing of asynchronous transfer mode (ATM) networks 相似文献
20.
Floyd提出的随机早丢弃(RED,random carly detection)是基于传统的泊松(Possion)模型,不适应网络流量普遍呈现自相似性的特点。基于此目的,提出了一种新的RED算法——Hurst加权随机早检测算法(HWRED,Hurst weighted random early detection)。新算法能够根据输入流量的自相似系数Hurst,调整RED算法参数。仿真结果表明,新算法提高了队列长度的稳定性,减少了丢包率、排队时延和排队抖动,提高了网络的链路利用率。 相似文献