ATM局域网仿真技术与路由器的使用

ＡＴＭ局域网仿真技术使得传统的以太网与令牌环网不须修改任何软硬件就可与ＡＴＭ网络互连，极大地保护了用户的已有投资。本文介绍了ＡＴＭ局域网仿真的主要部件与功能，ＡＴＭ局域网的仿真机制与过程，并对路由器在ＡＴＭ仿真网络中的应用作了说明     

ATM战术网研究与发展

下一代的战术网（Ｔａｃｔｉｃａｌ Ｎｅｔｗｏｒｋｓ）是基于ＡＴＭ技术的。本文指出了把ＡＴＭ技术应用到战术环境中面临的主要问题;介绍了ＡＴＭ战术网及其典型范例ＰＯＳＴ－２０００;分析了无线ＡＴＭ协议体系,把ＡＴＭ战术网与无线ＡＴＭ进行比较;通过ＡＴＮＥＴ工程分析了未解决的问题和研究方向;展望了ＡＴＭ战术网的发展。     

无线ATM会胎死腹中吗?

ＷＡＴＭ（无线ＡＴＭ）涉及到９０年代两个热点问题的结合，即ＡＴＭ技术和移动通信技术的结合。一些工业观察家认为ＷＡＴＭ必须解决三个问题。首先面临的问题是ＡＴＭ协议中的特性与无线信道特性不一致的问题。ＡＴＭ要求传输的比特错误率非常低（大约为１０－１０），...     

ATM热方兴未艾

本文介绍了ＡＴＭ（不传输模式）的当前发展势态，描述了ＡＴＭ新一代网络技术的优点及特性，以及ＡＴＭ的标准制订、推广应用情况，并论述了ＡＴＭ近几年内仍将与传统型网络技术综合存在的态势；ＡＴＭ网络技术乃是当今的主流发展方向。     

ATM网络基本原理

本讲座详细介绍了ＡＴＭ网络的基本原理，包括：ＡＴＭ网络的协议结构，连接与信令，拥挤与流控以及ＡＴＭ交换机的组成。     

ATM—LAN的仿真技术

ＡＴＭ－ＫＬＡＮ仿真技术实现了传统ＬＡＮ与ＡＴＭ－ＬＡＮ的集成和互操作在ＡＴＭ网络发展的初期具有十分重要的意义。本文详细介绍了ＡＴＭ论坛定义的ＬＮＡ的仿真体系结构并讨论了ＡＴＭ－ＬＡＮ仿真技术的有关问题。     

基于ATM的IP组播

介绍了ＩＰ组播和ＡＴＭ组播及当前在ＡＴＭ网络中实现ＩＰ组播的方法。讨论了ＩＥＴＦＲ基于ＡＴＭ的ＩＰ组播的优点与不足,描述了一个用ＡＴＭ网络传输多路ＭＰＥＧ－Ｉ视频信号的应用。     

ClassicalIP OverATM规范（下）

ＡＴＭ技术是目前最受人目的高速网络技术之一，而如何使ＡＴＭ网络与现有的国议相结合是ＡＴＭ技术发展的关键性问题。     

Internet综合业务模型在IP—ATM互联网络的服务照射

在ＩＰ－ＡＴＭ互联网络环境,ＡＴＭ子网在ＩＰ主机通信通过的路径上,ＡＴＭ网络边缘（入口和出口）设备将ＩＰ与ＡＴＭ网络物理上互联起来。在这种互联网络环境支持ＩＩＳ服务的时间,资源预约机制在ＩＰ网络实现资源预约,在ＡＴＭ子网,由边缘设备执行ＩＷＦ（ｉｎｔｅｒ ｗｏｒｋｉｎｇ ｆｕｎｃｔｉｏｎ）功能,为ＡＴＭ子网进行资源预约代理。边缘设备执行的ＩＷＦ功能中,一项重要的工作是进行ＩＰ ＩＩＳ服务模型到ＡＴ     

ATM局域网与局域网互联技术

由于日益增长多媒体技术的应用和对一般数据的高速传输业务的需求，ＡＴＭ技术应运而生。将ＡＴＭ引入局域网成败关键在于它是否能提供与现行协议和应用程序兼容的类似的局域网业务。为此，本文主要讨论ＡＴＭ引入局域网时，实现局网无连接服务，协议适配以及与ＡＴＭ广域网互联过程。     

支持综合业务的Internet-ATM网络及互联

文中阐述了Ｉｎｔｅｒｎｅｔ上综合业务的模式,介绍了资源预订协议ＲＳＶＰ、Ｉｎｔｅｒｎｅｔ流协议ＳＴ－ＩＩ、资源预先预订协议ＲｅＲＡ和几种主要的Ｉｎｔｅｒｎｅｔ与ＡＴＭ主干网络的互联协议以及传统的ＴＣＰ／ＩＰ协议族的报文在ＡＴＭ网络中传送的协议ＩＰ ｏｖｅｒＡＴＭ;阐述了局域网模拟ＬＡＮＥ的体系结构及其实现的一个实例和ＡＴＭ上支持多种网络层议（如ＩＰ,ＩＰＸ／ＳＰＸ,ＡｐｐｌｅＴａｌｋ等）的规范ＭＰ     

ATM上的IP交换技术

本文介绍了异步传输模式（ＡＴＭ）网络体系结构，重点叙述了其上的交换技术，并指出，ＡＴＭ中的ＩＰ交换技术将快速ＡＴＭ硬件直接与ＩＰ集成在一起，提高了信息的交换速度。这种解决方法综合了ＩＰ的简单性、伸缩性和健壮性，以及ＡＴＭ的速度快、容量高及多服务的通讯能力。     

IP multicast routing through ATM networks

The purpose of this paper is to have a closer look at the ‘core’ technology providing interworking between connectionless TCP/IP internetworks and switched ATM networks. The scope of the paper is IP multicast, while the main focus is on the network side of multicast, more precisely, on layers three and two of Internet architecture dealing with IP multicast routing. The paper analyses both practically available solutions and those being currently under discussion in IETF as Internet drafts. As a background of this comparison, the possible convergence of IP and ATM multicast service models is discussed. Major conclusions, based on simulation studies and scalability analysis are: (i) the high mapping overhead requires a separate address resolution service for unicast and multicast addresses; and (ii) efficient convergence has to make obsolete classical IP over ATM (M. Laubach, Classical IP and ARP over ATM, Network Working Group, Request for Comments: 1577, Category: Standards Track, January, 1994 [1]) in order to permit ‘cut-through’ within the ATM domain.     

An Interactive Telelecture System with Hybrid ATM/IP Networking

Currently, there is much debate whether ATM (Asynchronous Transfer Mode) or IP (Internet Protocol) is the better internetworking technology for multiparty multimedia applications. Proponents of ATM argue that only a connection-oriented network can satisfy the stringent timeliness requirements of high-quality audio and video data. Proponents of the Internet emphasize the scalability and flexibility of connectionless networking. In this paper a multiparty multimedia telelecture system, called Distance Learning Controller (DLC), is presented that uses both ATM and IP, thus, attempting to exploit the advantages of both technologies, without suffering the drawbacks of either technology. The DLC system uses ATM for transmission of broadcast-quality video and CD-quality audio, and IP-over-ATM for low-bandwidth applications and conference control functions. This paper describes the hardware and software components of the DLC system.     

基于NS2的校园网服务质量控制模型设计及实现

ATM(AsynchronousTransferMode)在多媒体应用中的服务质量QOS(QualityofService)的优势使其成为综合业务模型中的一种新的技术。文章首先介绍了QOS定义和VINT项目(VirtualInter-NetworkTestbed)及其网络模拟环境NS2(NetworkSimulation2),重点阐述了基于NS2的CIPOA(ClassicalIPoverATM)的具体模型的实现,并在此基础上实现了校园网络的一种用户优先级的QOS策略,通过控制ATM交换虚通道(SVCs)获得更好的服务质量。     

基于Ns的自适应IP流分类器的研究

基于IP的Internet取得了巨大的成功,也面临着新的挑战。IP和ATM结合技术是解决Internet存在问题的方法之一,文中讨论了三种IP技术的特点,分析了实现IP交换的几项关键技术,并给出了解决方案。在此基础上,构造了一个用来分析IP交换性能的IP交换流分类器的系统模型,最后介绍了开放式、事件驱动的网络仿真平台NS(NetworkSimulator),并利用NS来实现文中提出的自适应流分类器AFC的结构。     

QoS support for per-flow services: POS vs. IP-over-ATM

Packet-over-Sonet and IP-over-ATM are two ways to build high-speed Internet backbones. The work presented maps the parameters for Internet-standard integrated services onto ATM technical parameters and quantifies the performance of each architecture in terms of admissible connections carrying multimedia traffic. Results suggest that ATM networks will not be competitive with pure IP infrastructures over the long term     

ATM上实现IP技术的探讨与应用

文章对ATM与IP的几种结合技术作了详细的论述和比较，并结合我国实际情况，提出了利用ATM网建立INTERNET骨干网的基本模型     

Improved WWW multimedia transmission performance in HTTP/TCP overATM networks

Transmission control protocol/Internet protocol (TCP/IP) is the de facto standard of the networking world. It dynamically adjusts routing of packets to accommodate failures in channels and allows construction of very large networks with little central management. But IP packets are based on the datagram model and are not really suited to real-time traffic. In order to overcome the drawbacks, a new network technology, ATM, is proposed. ATM provides quality of service (QOS) guarantees for various classes of applications and in-order delivery of packets via connection oriented virtual circuits. Unfortunately, when ATM is to be internetworked with the existing network infrastructure, some special signaling, addressing and routing protocols are needed. IP over ATM is one of the methods proposed by IETF. It allows existing TCP/IP applications to run on ATM end-stations and ATM networks to interconnect with legacy LAN/WAN technologies. But the performance of TCP/IP over ATM leaves something to be desired. Partial packet discard (PPD) and early packet discard (EPD) are two schemes to improve its performance. This paper proposes a “selective packet retransmission” scheme for improving HTTP/TCP performance when transmitting through ATM networks. In selective packet retransmission, we take advantage of the property of humans' perception tolerance for errors to determine whether to retransmit a corrupted TCP segment or not. For lossable data, such as images, when an error occurs because of cell losses, it will not be retransmitted. The simulations show that, for the same buffer size and traffic load, selective packet retransmission performs better than PPD, EPD, and plain TCP over ATM     

未来宽带IP骨干网方案评述

随着Internet的发展,传统IP网已经不能满足用户对网络服务质量和综合多业务网的要求,从而提出发展宽带IP网的要求。主要介绍宽带IP骨干网的3种可行方案：IPoverATM、IPoverSDH/SONET及IPoverWDM的工作原理及其优缺点比较。