自相似业务合成流的建模及排队性能分析

近期起初网络流量分析表明很多信息源会产生在多时间尺度下具有自相似特性的信息流,据此人们采用模拟及分析的方法对此种业务流对ＡＴＭ交换机／复用器性能的进行了研究,发现了与传统短打关模型完全不同的排除生但是到２为止对于自相关信息流的复用问题尚未发现有要进行研究。而这个问题的解决对自相似业务流条件下的ＡＴＭ交换机／复用器性能分析,接入控制（ＣＡＣ）等都具有很重要的意义。本文基于临界时间尺度的概念对这个问题     

周期性业务流通过ATM复用器的时延抖动分析

ＡＴＭ通信网中需要传送多种业务，其中有一类是具有连续比特流的业务，这种业务的发送信元到达时间是周期性的，本文分析了一种周期性信元流通过ＡＴＭ复用器的排队模型，得出信元流排队时延的概率分布，时延抖动的自相关函数的功率谱。     

北电业务接入复用器（NSAM）

ＮＳＡＭ既有ＡＴＭ的灵活性，又有ＳＯＮＥＴ传输的可靠性。作为一种经济实用的复用器，ＮＳＡＭ可应用于ＡＴＭ技术，并将双向视频、音频、电话和数据业务融为一体。拥有了它，用户和业务供应商便可享受新型的高级应用，并使其网络面对任何挑战都立于不败之地。     

走近用户的ATM网

目前用户接入网广泛采用混合光纤／同轴网（ＨＦＣ）和非对称数字用户线（ＡＤＳＬ）技术,在此基础上建立ＡＴＭ网实现ＡＴＭ到家以适应未来宽带网的发展需要。基于ＨＦＣ网的ＡＴＭ网以ＡＴＭ节点交换、用户终端单元和头端单元设备来作支持。而在ＡＤＳＬ上完成ＡＴＭ交换业务时,则有两种方案可选：（１）通过在ＡＴＭ交换机与ＡＤＳＬ调制解调器之间加数字用户线接入复用器实现;（２）将离散多音频（ＤＭＴ）与ＡＴＭ相结合。     

输入为多媒体信源的ATM业务流警管方案

文章提出了一种输入为多媒体信源的利用模糊控制技术的ＡＴＭ网络业务流警管方案。文章以ＡＴＭ复用器为例，用ＭＭＢＰ模型讨论了了该方案的可能性，给出了模糊控制规则及其调整过程与实现步骤。仿真表明，该方案能满足多个不同语语音，图像，数据信源的分别或同时接入，其信元时延，丢失，抖动等服务质量 优于常规漏桶算法。     

具有质量控制功能的ATM交换节点的性能分析

本文提出一种用于ＡＴＭ网的质量控制方法－动态到达控制（ＤＡＣ），分析了采用ＤＡＣ的ＡＴＭ交换节点中，各类业务信元的丢失概率和平均时延，分析结果表明，ＤＡＣ是一种有效的质量控制方式，它能够提供多种服务等级以满足不同的需要，减小所有信元的平均时延，提高系统的有效吞吐量。     

ATM网络流量控制的研究

ＡＴＭ网络的流量控制是ＡＴＭ网络成功的关键。本文介绍了当今ＡＴＭ网络流量控制研究中比较流行的几种方法。     

一种信道复用器的设计与实现

介绍了一种MPEG2传送层复用器的软硬件结构,并对软件中一些重要功能模块进行了较详细描述。该复用器主要用于高清晰度电视信道技术的研制和节目传送流的复制。最后给出了实验结果。     

基于TMN的ATM网络管理

ＡＴＭ已从一种标准和原型变成了下一代的变换技术，随着大量的ＡＴＭ交换机进入网络，迫切需要与之相应的ＡＴＭ网络管理技术。本文重点讨论了如何将计算机和电信方法综合用于ＡＴＭ网络管理，特别是ＳＮＭＰ和ＣＭＩＰ协议在ＡＴＭ网络中的应用。另外，本文也讨论了ＴＭＮ接口及其与ＡＴＭ的网络元素ＮＥ的通信方式。     

ATM网络中ABR业务的监控方案

基于离散事件动态系统理论,提出了一种崭新的用于控制ＡＴＭ网络中ＡＢＲ业务流量的监控方案,这种方案具有简单易于实现的特点,仿真结果与理论预测值的一致证明了该方案的正确性。     

Wireless ATM: Performance Evaluation of a DSA++ MAC Protocol with Fast Collision Resolution by a Probing Algorithm

In general, the users of wireless ATM terminalsrequest the same functionality and quality of service asusers of wired terminals. These user requirements can betransformed into the demand for building an ATM multiplexer around the air interfacewhich is characterized by a radio channel inside. Themain difference between this virtual ATM multiplexeraround the air interface and a fixed ATM multiplexer is the distribution of the multiplexingfunction between wireless terminals and the basestation. For the uplink this requires a frequentnotification of the ATM cell scheduler in the basestation about the status of the incoming buffers inside thewireless terminals. This paper focuses on differentmethods for transmitting capacity request messages (alsodesignated as reservation request) over theuplink.     

Traffic profiles in ATM networks

A lot of studies have been made to characterize and model sources of ATM traffic (voice, data, video) and to evaluate the performance of a multiplexer whose input is a superposition of these sources, using different methods and techniques (fluid flow, matrix-analytic, etc.). However, in order to better understand the end-to-end performance of ATM connections, characterizations and models of ATM traffic inside the network (i.e. after passage through one or more network elements) are needed. In this paper we intend to study the following problems: (i) Traffic profile of an ATM connection after being policed, in particular worst case traffic, and evaluation of the performance of the related statistical multiplexer. (ii) Traffic profile of the output of a multiplexer (characterized by means of the interdeparture time distribution and the index of dispersion for counts and the index of dispersion for interarrival times). (iii) Traffic profile of a single connection after passing a multiplexer. The aim is to obtain useful characterizations and models of ATM traffic in order to evaluate the performance and the efficiency of ATM network elements and of traffic control functions.This work was supported in part by the Commission of the European Communities, under project RACE R2024 (Research and Development on Advanced Communications in Europe) on Broadband Access Facilities.     

Simulation study on ATM multiplexing of MPEG video sources

In this paper we study the performance of ATM multiplexing of homogeneous MPEG video sources. A source scheduling method is developed to improve the performance of ATM multiplexer for MPEG video sources. Simulation results show that the level of burstiness for the aggregated MPEG traffic is reduced and the network performance is enhanced. Based on the rationale of the source scheduling method, a simple but efficient bandwidth allocation algorithm is also derived for connection admission of MPEG video in an ATM multiplexer. Copyright © 2001 John Wiley & Sons, Ltd.     

AAL2分组话音复接器的研究与实现

该文研究在ATM虚通路带宽利用率一定的条件下,AAL2分组话音复接器性能随ATM虚通路输出速率的增加而变化的情况。得出结论:当ATM虚通路带宽利用率一定时,ATM虚通路输出速率越高,AAL2分组话音复接器的分组丢弃概率和平均分组排队时延越小。并提出了一种AAL2分组话音复接器的实现方案。该方案可以随着ATM虚通路输出速率的增加,方便地复接多个E1话音电路上的话音数据。     

多信源ATM分组语音图像流的分析

分析了ATM复用器中的分组语音图像流.为研究多信源、大流量条件下的流量特性,我们将语音源近似为马尔柯夫泊松过程MMPP(2).2个泊松过程的平均到达率由生灭链得出,转移率则通过极限定理,由高斯过程的矩匹配MMPP(2)相应参数而获得.同时,我们运用流体流法来解决复用缓冲性能.同样的方法适用于图像源及语音图像合成源的情况.     

Performance Analysis of an ATM Multiplexer with Multiple QoS VBR Traffic

In this paper, we propose a new queuing model, MMDP/MMDP/1/K, for an asynchronous transfer mode (ATM) multiplexer with multiple quality of service (QoS) variable bit rate (VBR) traffic in broad band-integrated services digital network (B-ISDN). We use the Markov Modulated Deterministic Process (MMDP) to approximate the actual arrival process and another MMDP for service process. Using queuing analysis, we derive a formula for the cell loss probability of the ATM multiplexer in terms of the limiting probabilities of a Markov chain. The cell loss probability can be used for connection admission control in ATM multiplexer and the calculation of equivalent bandwidth for arrival traffic. The major advantages of this approach are simplicity in analysis, accuracy of analysis by comparison of simulation, and numerical stability.     

突发性业务环境下周期性信元流通过ATM复接器的时延抖动

在输入ATM网络的业务源中,周期性信元流是很重要的一种.本文精确地分析了一个有限缓存的ATM复接器,其输入业务源由一路周期性信元流、多路随机性贝努利(Bernoulli)信元流和突发性两状态马尔科夫调制贝努利(MMBP)信元流构成.得出了该路周期性信元流的排队时延分布、时延抖动的自相关函数和功率谱.揭示了突发性业务环境下周期性信元流通过ATM复接器的时延抖动行为.计算机模拟验证了分析结果的正确性.     

Voice over ATM using AAL2 and bit dropping: performance and calladmission control

Asynchronous transfer mode (ATM) adaptation layer 2 (AAL2) has been designed for efficient transport of voice, fax, and voiceband data (VBD) traffic over an ATM virtual circuit. The protocol helps achieve low latency and high bandwidth efficiency while applying suitable compression methods on voice/VBD/fax calls and silence elimination on voice calls. We analyze the performance and capacity of an ATM multiplexer based on AAL2 adaptation. We assume that embedded adaptive differential pulse code modulation (ADPCM) is used to compress voice, and silence elimination is used to achieve statistical multiplexing gain. The embedded ADPCM coding scheme allows selective dropping of less significant bits of voice during congestion in the ATM/AAL2 multiplexer. We compare the call capacities of voice multiplexers with and without bit dropping (BD). The performance models and results presented are based on fairly general assumptions and can be used for traffic engineering and call admission control in land-line or wireless ATM systems for a variety of voice/voiceband compression algorithms. A generalized algorithm for call admission control is also described     

DELAY JITTER OF A PERIODIC CELL STREAM THROUGH AN ATM MULTIPLEXER IN A BURSTY TRAFFIC ENVIRONMENT

The periodic cell stream is a very important member among the input traffic sources in ATM networks. In this paper, a finite-buffered ATM multiplexer with traffic sources composed of a periodic cell stream, multiple i.i.d Bernoulli cell streams and bursty two-state Markov Modulated Bernoulli Process (MMBP) cell streams is exactly analyzed. The probability mass function of queuing delay, the autocorrelation and power spectrum of delay jitter for this periodic cell stream are derived. The analysis is used to expose the behavior of delay jitter for a periodic cell stream through an ATM multiplexer in a bursty traffic environment. The simulation results indicate that the analytical results are accurate.