Exact fluid-flow analysis of single on/off source feeding an ATMbuffer

A formula is developed to calculate the cell loss probability for an ATM buffer fed by a single ON/OFF source. This fluid-flow method uses balance equations to give a geometric progression for the state probabilities. Results show better accuracy than fluid-flow analysis based on differential equations. This cell loss formula can be applied as a more accurate component in connection admission control and bandwidth management algorithms for ATM networks     

N*DPT/D/1排队系统分析

多路离散周期串到达、单个服务台定长服务排队系统,是在研究CBR业务下ATM网络中间节点性能时所遇到的一种排队模型。在有线ATM网的CBR业务接进无线ATM网时也会遇到这种排队模型。本文分析了这一排队系统,得到了其队长剩余分布的计算公式。     

在ATM网络中采用业务流自适应分布优化控制的拥塞概率分析

本文提出了一种降低ＡＴＭ网络拥塞率的业务流量分布自适应优化控制方法,建立了一种碰撞函数型的新的距离测度,并建立了多种业务环境下拥塞概率的分析模型,得出了多端口拥塞的计算公式,研究结果表明,业务流量分布的自适应优化控制技术能很好的改善ＡＴＭ网络内的业务流量分布,大大降低了信道拥塞率。     

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.     

A novel approach to estimating the cell loss probability in an ATMmultiplexer loaded with homogeneous on-off sources

Estimating the cell loss probability in an ATM multiplexer is one of the most important problems concerning congestion control and bandwidth management in an ATM-based BISDN. We propose a new approach to estimating the cell loss probability in an ATM multiplexer. We use the Markov modulated deterministic process (MMDP) to approximate the actual arrival process and then model the ATM multiplexer as an MMDP/D/1/K queueing system. Using queueing analysis, we derive a formula for the cell loss probability expressed in terms of the limiting probabilities of a Markov chain. We propose two approximation methods based on the results of the analysis. The actual arrival process is approximated by an (M+1)-state MMDP in the first method and by a two-state MMDP in the second. The major advantages of both methods are simplicity, computational efficiency, and numerical stability. The most attractive feature of the second method is that the cell loss probability can be expressed in closed form. Numerical and simulation results show that the first method is sufficiently accurate for all cases in which burst-level congestion is the main contributing factor to cell loss, while the closed-form formula is sufficiently accurate for applications where the average burst length is large (such as large file transfers, image retrievals, etc.)     

Decay rate (ER) modelling of G/D/1 queue, and results for ATMtelecommunications

The authors present a new formula for calculating the decay rate in the queueing system G/D/1. This queueing model has potential for application in cell-based telecommunication systems, such as ATM, since it allows generally distributed inter-cell arrival times, while keeping the cell transmission time constant. The results presented here show that considerable improvements in accuracy are now available     

基于GMM与EM算法的呼叫接入控制

【摘要】研究了ATM通信网络基于高斯混合模型的呼叫接入控制问题。提出了使用高斯混合模型来近似聚合通信流带宽分布的概率密度函数,通过EM算法来估计混合模型的参数并导出了基于高斯混合模型的允许接入控制公式。     

ATM SAR处理器发送数据业务的信元调度算法

叙述了ＡＴＭ ＳＡＲ（Ｓｅｇｍｅｎｔａｔｉｏｎ Ａｎｄ Ｒｅａｓｓｅｍｂｌｙ）处理器发送信元的机理,讨论了基于发送调度表的业务成形方式产生的信元时延抖动（Ｃｅｌｌ Ｄｅｌａｙ Ｖａｒｉａｔｉｏｎ,ＣＤＶ）以及信元时延抖动容限（Ｃｅｌｌ Ｄｅｌａｙ Ｖａｒｉａｔｉｏｎ Ｔｏｌｅｒａｎｃｅ,ＣＤＶＴ）,推导了ＣＤＶＴ的计算公式,设计了使最小的信元调度算法ＮＶＳＴ（Ｎｅａｒ Ｖｉｒｔｕａｌ Ｓｄｅｎ Ｔ     

环境气压对衍/折光学系统消二级光谱设计的影响

研究了环境气压对宽光谱、长焦距衍／折混合光学系统消二级光谱设计的影响。推导了环境压力变化时阿贝数变化对像面移动的影响。采用离焦法对系统进行校正,当环境气压变化小于0．5Pa时,系统的像面移动不超过O．8mm,研究了本系统使用的玻璃和衍射元件的综合气压特性,对解决其他光学系统气压的影响有一定的指导意义。     

TCP在无线ATM环境下的性能分析

本文对无线ATM网络环境下的TCP性能进行了分析.首先,对TCP的吞吐量效率进行了理论分析,并根据广域网流量分布的特点,选取几个典型的TCP报文段长,得到了TCP吞吐量效率与误信元率的关系.然后,通过在OPNET平台上进行仿真,证明了理论分析的合理性,并得出了结论.进一步地,对TCP最佳报文段长与误信元率的关系进行了分析,提出应根据误信元率情况调整传输控制协议报文段长,从而获得最大的吞吐量效率.     

ATM everywhere?

The use and deployment of asynchronous transfer mode (ATM) in a target of operating environments and administrative domains are discussed. The operating environments include wide area ATM, regional area ATM, local area ATM, desk area ATM, and local wireless ATM. The challenges of interdomain ATM are reviewed     

混合的ATM技术

ＡＴＭ协议体系结构分为物理层，ＡＴＭ层，ＡＬＬ层和高层，如果在终端用户处完全实现这些功能，不仅造价大，还要放弃用户在网卡，网络软件上的投资。而在终端用户的协议栈中采用混全的方案，则能保留现有网络技术的一些协议层次，又加入ＡＴＭ的协议层次，可以在将用户接入ＡＴＭ网的同时，保护用户已有的网络投资。     

基于标值更新通信量模型的ATM缓冲区信元丢失率分析方法

提出了一种不同于传统分析方法（如ＭＭＰＰ／Ｄ／１）的直接基于输入通信量带宽分布和自相关特性的信元丢失率分析方法,应用标值更新模型近似实际输入通信量的低阶统计特性,给出了一个基于马尔柯夫链极限概率的信元丢失率估计公式。该方法可以估计突发级的信元丢失率,而且具有算法简单,计算量小,数值稳定性好等特点。     

Analysing the interdeparture process in an ATM multiplexer

This paper studies the interdeparture process in a mathematical model of an ATM multiplexer. The technique is based on a discrete-time queueing model of k input queues feeding one output queue, a situation commonly arising in ATM switches. The process between input queues and output queue is analysed in detail. For a service rate of one cell per time slot (s = 1) the exact solution of the interdeparture process is given based on the binomial distribution. For a service rate greater than one cell per time slot (s > 1) a solution is derived using the state probabilities of the input queues. The probability density function of the interdeparture process is then obtained by summing a combination of the multinomial joint distribution function of s random variables. If the state probabilities are referred to as the distribution of buffer contents after arrival, the formula returns exact results. © 1998 John Wiley & Sons, Ltd.     

ATM基本技术及其在公用网应用的主要难点

ＡＴＭ技术已被公认为实现宽带综合业务数字网（Ｂ－ＩＳＤＮ）的关键技术。本文将介绍ＡＴＭ技术的基本原理－ＡＴＭ概念，ＡＴＭ协议的分层结构，ＡＴＭ网络和接口，ＡＴＭ传输与复用技术，ＡＴＭ的交换技术，ＡＴＭ的信令方式，ＡＴＭ网络管理和管制以及ＡＴＭ技术在公用网应用中的主要难点。     

Wireless ATM LAN with and without infrastructure

We consider wireless ATM concepts for small LANs, especially for SOHO and future consumer applications. We describe a wireless ATM LAN framework architecture that supports wireless ATM communications in environments with and without fixed ATM infrastructure. For the configuration with an ATM infrastructure, a distributed ATM switched backbone is proposed, which enables a smart ATM switching element to be embedded in every wireless and fixed access point. For bandwidth efficiency and ease of operation (place-and-play), we also propose an ad hoc wireless ATM LAN concept based on the same 5 GHz wireless ATM air interface as is currently under standardization in the ETSI/BRAN and ATM Forum. Unlike CSMA-based ad hoc systems such as HIPERLAN and IEEE802.11, our ad hoc wireless ATM system makes QoS management feasible in an infrastructureless environment by using resource reservation and scheduled medium access protocol. Since cost scalability is essential throughout our system design, we consider forwarding between ad hoc subnets and interworking with the fixed network as important but optional features     

ATM traffic management and congestion control using fuzzy logic

The paper focuses on the use of fuzzy logic in network management, ATM congestion control, and ATM switching. The ATM network management ensures traffic agreement at the source level in order to prevent congestion situations from occurring. The paper reviews work in the area of traffic policing and introduces a scheme for improving the performance of a fuzzy policer. The ATM fuzzy switch introduced, enhances the capabilities of the ATM switch, one of the most critical elements in the ATM network     

雷达组网通信中的ATM交换机

介绍了ＡＴＭ交换技术在雷达组网通信中的应用。通过对基于中央处理站的雷达组网通信技术需求的分析，提出了一种类似于用户—服务器模式的ＡＴＭ交换结构。ＡＴＭ技术是Ｂ—ＩＳＤＮ的基础，ＡＴＭ交换技术是ＡＴＭ技术的核心，它不仅可用于民用通信业务，而且对于电子干扰环境下雷达网对密集多目标跟踪时所涉及的通信业务也很有效。文章对ＡＴＭ交换机在雷达网中的数据交换作了分析，并以计算机仿真手段评估了三种特定通信环境下输出缓冲型ＡＴＭ交换机的利用率和输出队列概率分布情况。     

Wireless ATM—an overview

This paper sketches the requirements and possibilities of wireless ATM in local area networks. Because of the wide range of services supported by ATM networks, ATM technology is expected to become the dominant networking technology in the medium term for both public infrastructure networks and for local area networks. ATM infrastructure can support all types of services, from time-sensitive voice communications and desk-top multi-media conferencing, to bursty transaction processing and LAN traffic. Extending the ATM infrastructure with a wireless access mechanism meets the needs of those users and customers that want a unified, end-to-end networking infrastructure with high-performance, consistent service characteristics. The paper introduces ATM concepts, discusses the requirements for wireless ATM, in particular for data link control and radio functions. It closes with some notes on development of wireless ATM research systems standardization and spectrum allocations.     

ATM local area networks: a survey of requirements, architectures,and standards

There is increasing interest in deploying ATM technology in local or campus networks. ATM is an ideal technology to overcome many of the limitations of today's LAN technologies. This article focuses on the application of ATM in the LAN environment to interconnect high-end host computers, and on the interworking of ATM-based LANs with legacy LANs. The authors introduce ATM LAN requirements, followed by a discussion of possible ATM LAN architectures to support these requirements. The article then covers current standards and their relation to the possible architectures, and concludes with a discussion of current ATM LAN issues and directions