ATM交换技术

交换技术可以分为4种基本技术：电路交换、分组交换、侦交换和信元交换。电路交换来用时分复用方式，其优点是时延小，而缺点是速度低。分组交换来用存储转发，其优点是速度高，带宽可调整，而其缺点是时延很大。帧交换采用读取发送方式，其优点是速度高，成本任．校点是无闻述情息，广播式传任，定位于LAN。信元交权采用ATM，其优点是对延小，速度高，带宽可调节，其缺点是部分信无重传．一、ATM发展的必要性1．从电话网上署一方面，目前电话网的传输干线和大城市的市话中继线大都已采用光如，传输速率从34kbit八到2．SGbit八，而程控…     

基于逆向传输机制的反馈型两级交换结构

为解决FTSA-2-SS结构中的信元冲突、信元失序以及交换流程复杂化等问题,该文提出一种基于逆向传输机制的反馈型两级交换结构(FRTM-TSA)。该结构通过crossbar逆向传输机制使得任意输入端口均可获得其相邻端口的调度结果并以此对目标端口所反馈的缓存信息进行修正,基于修正后的信息进行算法调度使得FRTM-TSA能够避免信元冲突和信元失序,也无需在输出端口设置重排序缓存。理论分析和仿真结果均表明FRTM-TSA能够以相对简洁的交换结构和交换流程获得更优的时延性能。     

一种基于Credit的变长分组并行交换网络调度算法

该文提出了一种新的并行分组交换(PPS)网络调度算法。该算法通过在解复用器处采用以变长分组为业务分配单元的方式消除了信元的乱序问题;通过采用Credit机制进行业务分配,实现了业务到各个交换平面完全公平的分配;各个并行交换单元采用组合输入输出排队,降低了对缓存和交换平面的加速要求,同时可以充分利用现有单Crossbar网络调度算法的研究成果。文中证明了该算法对业务分配的公平性,对高速缓存的需求量以及整个网络的稳定性,仿真进一步证明了该算法具有良好性能。     

现代电信交换技术（9）

5.4 ATM交换系统 ATM信元中承载的是宽带综合业务,因此信元交换应该是功能丰富、概念全新的一种交换技术。它应该像电路交换方式一样适用于电话业务,也应像分组交换方式一样适用于数据业务及其它业务。我们从改进分组交换、使其能满足实时性业务;或从改进电路交换、使其能满足灵活适配不同速率业务的两个不同角度出发,最终都发展到ATM交换。所以,ATM交换是电路交换与分组交换相结合的     

现代电信交换技术（6）

5 ATM交换技术5.1 ATM的基本概念5.1.1 ATM与电路转送、分组转送的关系 ATM是异步转送方式的简称。转送是指电信网中传输、复接和交换方式的整体。ATM是各种转送方式中的一种。ITU—T定义ATM为:“以信元为信息传输、复接和交换的基本单位的转送方式”。在电信网上已经广泛使用的有电路转送方式和分组转送方式。     

ATM信元总线交换技术及其应用的研究

文章分析了信元总线型ＡＴＭ交换技术的特点与应用范围，研究了这一交换方式的工作机制以及总线争用仲裁、总线寻址、交换路由控制等关键技术等问题。最后给出了一种信元总线交换的典型应用。     

互联网络中的数据通信交换技术研究

交换是指按照某种方式对传输线路的资源进行分配,交换技术主要包含了报文的交换、分组的交换、线路的交换等几个方面。目前的宽带数据通信网出现了两种不同的技术,即IP与ATM,IP的网络核心节点为太位路电器;ATM的网络核心节点为ATM交换机,其目的为了实现信元的高速交换。     

光ATM交换技术异军突起

光ＡＴＭ交换是光交换网络和ＡＴＭ交换结构相结合而形成的一种颇具潜力的交换技术。本文分析了光ＡＴＭ技术产生的背景，描述基于使用超短光脉冲的广播－和－选择星形网络以及基于使用光矩阵交换的超正方体网络这两类信元交换结构，介绍了实现光ＡＴＭ交换的几项关键技术：超速信元产生、全光地址匹配和全光同步，探讨光交换技术未来的发展趋势和前景。     

基于TCP交换的电路交换与分组交换融合方法

宽带实时网络业务的发展使得分组交换逐渐不能满足提供高服务质量(QoS)保证的要求，融合电路交换与分组交换以形成优势互补已成为网络技术发展的迫切需求。基于该需求，提出了融合电路交换与分组交换的基于TCP交换的新方法。以网络核心使用电路交换，提高核心带宽利用率；在网络边缘采用分组交换的技术，发挥其方便灵活组网模式。文章分析了TEP交换需要解决的主要问题，在此基础上较详细的讨论了，TCP交换中由IP路由协议创建与撤销电路链路的过程；分析了边界路由器与核心路由交换机所需完成的主要功能与任务；实现TCP交换所必须研究的关键技术。     

从电路交换到ATM交换——交换技术发展100年纵览

交换技术有电路交换和分组交换这两种不同的方式,文章简要回顾了交换技术的发展,并着重介绍了两者的结合——ATM交换技术。     

Uniform switching system by families of switching sets

A new mathematical method in coding theory that is applicable to various practical problems in communication systems is introduced. The uniform switching system based on k-sets is defined, and its cardinalities, an index system, and error correctabilities are studied. The cardinalities of a uniform switching system based on general families of switching sets are discussed. The asymptotic cardinality is obtained for the Reed-Muller codes of general order     

Laser-controlled switching

A new type of laser switching is discussed. The laser produces volume ionization in the path of a propagating streamer, increasing its velocity. Subnanosecond jitter is thereby obtained with pressurized gas switches.     

Techniques for optical packet switching and optical burst switching

Wavelength-division multiplexing appears to be the solution of choice for providing a faster networking infrastructure that can meet the explosive growth of the Internet. Several different technologies have been developed so far for the transfer of data over WDM. We survey two new technologies which are still in the experimental stage-optical packet switching and optical burst switching-and comment on their suitability for transporting IP traffic     

Hybrid switching and p-routing for optical burst switching networks

One promising switching technology for wavelength-division multiplexing optical networks is optical burst switching (OBS). However, there are major deficiencies of OBS. (1) The delay offset between a control message and its corresponding data burst is based on the diameter of a network. This affects network efficiency, quality-of-service, and network scalability.( 2) OBS adopts one-way resource reservation scheme, which causes frequent burst collision and, thus, burst loss. We address the above two important issues in OBS. In particular, we study how to improve the performance of delay and loss in OBS. To reduce the end-to-end delay, we propose a hybrid switching scheme. The hybrid switching is a combination of lightpath switching and OBS switching. A virtual topology design algorithm based on simulated annealing to minimize the longest shortest path through the virtual topology is presented. To minimize burst collision and loss, we propose a new routing algorithm, namely, p-routing, for OBS network. The p-routing is based on the wavelength available probability. A path that has higher available probability is less likely to drop bursts due to collision. The probability-based p-routing can reduce the volatility, randomness, and uncertainty of one-way resource reservation. Our studies show that hybrid switching and p-routing are complementary and both can dramatically improve the performance of OBS networks.     

A pseudo-CCM/DCM SIMO switching converter with freewheel switching

This paper presents a single-inductor multiple-output (SIMO) converter operating in pseudo-continuous conduction mode (PCCM) and/or discontinuous conduction mode (DCM). With the proposed freewheel switching control, this converter can handle large load currents with a much smaller current ripple, while retaining low cross regulation. It can also work in DCM for high efficiency at light loads. A prototype of a single-inductor dual-output (SIDO) boost converter was fabricated with a standard 0.5-/spl mu/m CMOS n-well process. The two outputs are regulated at 2.5 and 3.0 V, respectively. At an oscillator frequency of 1 MHz, the efficiency reaches 89.4% at a total output power of 320 mW. Compared with prior designs, both current and voltage ripples are reduced. This design can be extended to have multiple outputs and for different types of dc-dc conversions, or be applied to single-output converters for fast transient response.     

Performance comparison between fixed length switching and variable length switching

Fixed length switching (FLS) and variable length switching (VLS) are two main types of switching architecture in high‐speed input‐queued switches. FLS is based on a cell‐by‐cell scheduling algorithm, while VLS operates on the variable packet granularity. This paper aims to make a comprehensive comparison between these two switching modes to guide the industrial design and academic research. We use stochastic models, Petri net models, analysis and simulations to investigate various performance measures of interest. Average packet latency, bandwidth utilization, segmentation and reassembly overhead, as well as packet loss are the identified key parameters that influence the outcome of the comparison. The results achieved in this paper are twofold. On one hand, it is shown that FLS enables smaller packet loss and lower packet delay in case of a short packet. On the other hand, VLS favors better bandwidth utilization, reduced implementation complexity and lower average packet delay. We recommend VLS in the conclusion since its disadvantages can be compensated by some methods, while the problems in FLS are difficult to be solved. Copyright © 2007 John Wiley & Sons, Ltd.     

Novel type of switching network composed of digital switching matrices

A new type of one-stage switching network comprising digital switching matrices is proposed. In many cases such a network contains fewer matrices than currently known networks. The proposed one-stage networks can be used as submodules for cost-effective multistage networks.<>     

Broadband video switching

A broadband 64×16 space-switching approach and its applicability to large-scale broadband switching systems are described. The design uses a technique that prevents the parasitic capacitances from reducing the switching speed. The switching system was implemented in 3-μm CMOS VLSI and operated in excess of 150 Mb/s. Computer simulation indicates a 1-Gb/s potential with a 1-μm CMOS implementation