在ATM网上实现局域网功能的困难及对策

ＡＴＭ网络作为下一代网络，终装成为网络的主流。但量ＡＴＭ网要在目前传统局域网点主导地位的环境下成为今后的主流和发展的方向，就必须解决二个问题；首先必须使已有的众多的网络应用软件能在ＡＴＭ工作站上使用；第二，ＡＴＭ网应能很容易和传统的局域网连在一起的工作站一起动作。     

宽带IP网技术进展

宽带ＩＰ网技术近一年来发展迅速，由于它具有效率高，性能好，设备省，成本低，协议单一的优点，特别适合于我国的网络建设。运行统一的ＩＰ协议的以太网取代Ｂ－ＩＳＤＮ及ＡＴＭ成为局域网，企业网及城域网的主流。线速路由交换机和密集波分复用技术的成熟和走向商品化，结合产生了ＩＰ优化光学网络，由于省去了ＳＤＨ和ＡＴＭ设备，它将是宽ＩＰ网的最优方案，宽带ＩＰ网将可以满足分类服务（ＣＯＳ）和质量保证（ＱＯＳ）服务，     

局域网接入ATM网技术（二）

局域网接入ＡＴＭ网是信界最热门的技术之一。如何既享受ＡＴＭ的高带宽，又保留局域网现有的协议层次，从而保护用户投资，是一个很吸引人的技术问题ＩＰ Ｏｖｅｒ ＡＴＭ（ＩＰＯＡ），局域网仿真（ＬＡＮ Ｅｍｕｌａｔｉｏｎ）以及Ｍｕｌｔｉ－Ｐｒｏｔｏｃｏｌ Ｏｖｅｒ ＡＴＭ（ＭＰＯＡ）是局域网接入ＡＴＭ的三种最流行的技术规范。其中，局域网仿真和ＭＰＯＡ适用范围广，可以接入各种网络层协议。这里对局域网仿真和Ｍ     

局域网接入ATM网技术（三）

局域网接入ＡＴＭ网是通信界最热门的技术之一。如何既享受ＡＴＭ的高带宽，又保留局域网现有的协议层次，从而保护用户投资，是一个很吸引人的技术问题，ＩＰＯＶｅｒＡＴＭ（ＩＰＯＡ）、局域网仿真以及Ｍｏｕｌｔｉ－ＰｒｏｔｏｃｌｏＯｖｅｒＡＴＭ（ＭＰＯＡ）是局域网接入ＡＴＭ的三种最流行的技术规范。其中，局域网仿真和ＭＰＯＡ适用范围广，可以接入各种网络层协议。这里对局域网仿真和ＭＰＯＡ这两种技术的原理、通信规程     

城域以太网技术应用与实施

以太网技术起源于30年前局域网组网协议和技术，发展到今天，97％以上的终端用户通过以太网接口进实现各种形式的联网。由于以太网技术配置简单，组网灵活，价格低廉，而且技术本身已经被大多数人所熟悉和接受，因此以太网组网技术发展迅速。各种迹象表明，以太网在局域网中表现出的种种优势，正在逐渐使其成为城域网甚至广域网中的承载网络，虽谈不上是对传统承载网络和专线业务的替代，至少也将成为主流传送网技术之一。为了实现与传统电信级传送网(如SDH)和承载网(如ATM／FRPVC)相同的可靠性，     

Classical IP Over ATM规范(下)

ＡＴＭ（异步传输模式）技术是目前最受人瞩目的高速网络技术之一，而如何使ＡＴＭ网络与现有的网络协议（如ＴＣＰ／ＩＰ）相结合是ＡＴＭ技术发展的关键性问题。本文通过对比分析了在ＡＴＭ局域网与传统局域网上ＩＰ协议实现的异同，并较为深入地介绍了在ＡＴＭ上运行ＴＣＰ／ＩＰ协议的技术方案。     

Classical IP Over ATM规范(上)

ＡＴＭ（异步传输模式）技术是目前最受人瞩目的高速网络技术之一，如何使ＡＴＭ网络与现有的网络协议（如ＴＣＰ／ＩＰ）相结合是ＡＴＭ技术发展的关键性问题。本文通过对比分析了在ＡＴＭ局域网与传统局域网上ＩＰ协议实现的异同，并较为深入地介绍了在ＡＴＭ上运行ＴＣＰ／ＩＰ协议的技术方案。     

ATM局域网硬件系统

ＡＴＭ局域网硬件系统●杨卫平在ＡＴＭ局域网（ＬＡＮ）中，交换机和主机间的每一物理连接或主机间的物理连接都是点对点的，因而组建一个ＡＴＭ局域网需要两类硬件：一类是ＡＴＭ主机接口卡，它使得主机能够连到ＡＴＭ网络上；另一类为ＡＴＭ交换机，它作为网络结点出现...     

北京ATM试验网概况

简介了ＡＴＭ的特点、优点和三层网结构概念以及广州、上海和北京的ＡＴＭ网开发情况。介绍了北京ＡＴＭ试验网的网络构成、设备配置和分阶段试验的内容；提出北京试验网从试验到应用的近期规划和达到的目标，以及在规划设计中应注意的问题。     

宽带网业务发展前景

９０年代初,ＡＴＭ网络在国外开始出现。近几年来,国内也相继建成了ＡＴＭ网络,或以ＡＴＭ为核心的帧中继网。１９９５年上海建立了宽带试验网,主要进行影视点播、会议电视、校园网互连、ＡＤＳＬ的高速数据接入、远程教学、远程医疗等试验。１９９８年上海市邮电管理局又建成了上海帧中继网（又称上海宽带网）,该网以ＡＴＭ交换机为核心节点,边缘节点可提供各种业务的接入。另外,江苏省。山东省、浙江省、福建省、北京、广州等地也先后建成了宽带网。一、宽带ＡＴＭ网业务现有ＡＴＭ网上的应用主要为传统业务（ＡＴＭ／ＦＲ的ＰＶＣ…     

Cells-In-Frames: a system overview

Cells-In-Frames provides an efficient mechanism for integrating both voice and data traffic on an existing campus network that is currently supporting legacy LAN workstations. The solution suggested by this article is to export ATM services within standard LAN frames. Each frame will carry the traffic from one or more ATM cells, but any given LAN frame is associated with only one ATM virtual circuit. The widely different qualities of service required for voice and data traffic is achieved rough the use of AAL1 and AAL5 services. The AAL functions are split appropriately between the workstation and the LAN switch that interfaces to an ATM backbone network. With the use of the Q.2931 signalling protocols defined for ATM, Cells-in-Frames achieves a long-sought-after goal of providing switched networking services to LAN-attached workstations     

Flight of the FALCON [ATM]

The fabric-based ATM oriented local connectivity (FALCON), an ATM-based customer premises network (CPN), is described. FALCON supports access using traditional local area networks (LANs) such as Ethernet and token rings and supports a LAN emulation mode for its native ATM interface. This service allows a set of terminals, workstations, and servers to connect to the switch-based network and to interact as if they were attached to a traditional LAN. FALCON's backbone structure is based exclusively on ATM technology, all following CCITT or industry standards wherever they apply. The FALCON control structure is outlined     

Experience with PACS in an ATM/Ethernet switched networkenvironment

Legacy local area network (LAN) technologies based on shared media concepts are not adequate for the growth of a large-scale picture archiving and communication system (PACS) in a client-server architecture. First, an asymmetric network load, due to the requests of a large number of PACS clients for only a few main servers, should be compensated by communication links to the servers with a higher bandwidth compared to the clients. Secondly, as the number of PACS nodes increases, the network throughput should not measurably cut production. These requirements can easily be fulfilled using switching technologies. Here asynchronous transfer mode (ATM) is clearly one of the hottest topics in networking because the ATM architecture provides integrated support for a variety of communication services, and it supports virtual networking. On the other hand, most of the imaging modalities are not yet ready for integration into a native ATM network. For a lot of nodes already joining an Ethernet, a cost-effective and pragmatic way to benefit from the switching concept would be a combined ATM/Ethernet switching environment. This incorporates an incremental migration strategy with the immediate benefits of high-speed, high-capacity ATM (for servers and high-sophisticated display workstations), while preserving elements of the existing network technologies. In addition, Ethernet switching instead of shared media Ethernet improves the performance considerably. The LAN emulation (LANE) specification by the ATM forum defines mechanisms that allow ATM networks to coexist with legacy systems using any data networking protocol. This paper points out the suitability of this network architecture in accordance with an appropriate system design     

The Tera project: a hybrid queueing ATM switch architecture for LAN

The Tera ATM LAN project at Carnegie Mellon University addresses the interconnection of hundreds of workstations in the Electrical and Computer Engineering Department via an ATM-based network. The Tera network architecture consists of switched Ethernet clusters that are interconnected using an ATM network. This paper presents the Tera network architecture, including an Ethernet/ATM network interface, the Tera ATM switch, and its performance analysis. The Tera switch architecture for asynchronous transfer mode (ATM) local area networks (LAN's) incorporates a scalable nonblocking switching element with hybrid queueing discipline. The hybrid queueing strategy includes a global first-in first-out (FIFO) queue that is shared by all switch inputs and dedicated output queues with small speedup. Due to hybrid queueing, switch performance is comparable to output queueing switches. The shared input queue design is scalable since it is based on a Banyan network and N FIFO memories. The Tera switch incorporates an optimal throughput multicast stage that is also based on a Banyan network. Switch performance is evaluated using queueing analysis and simulation under various traffic patterns     

Designing a practical ATM LAN

The adaptor cards and driver software for workstations and local asynchronous transfer mode (ATM) switches and switch control software used in an ATM local area network (LAN) system are discussed. It is shown that the ATM hardware and software components together provide services that are essential for ATM to be considered a realistic alternative to current shared-media LANs. These services include: completely transparent support for the TCP/IP protocol suite, an application programming interface for full access to the underlying ATM capabilities, support for AAL5, AAL3/4, and the null AAL, both connection-oriented and connectionless service, dynamic connection establishment or switched virtual circuits, resource reservation of guaranteed bandwidth and quality of service, full-bandwidth multicast and broadcast, virtual path and channel routing among multiple switches, automatic configuration and failure recovery, dynamic address assignment and internetwork address resolution, and network management via the simple network management protocol (SNMP)     

虚拟局域网

虚拟局域网是网络用户独立于网络物理配置和位置的一个逻辑组合，综结合了网络交换和管理功能，使网络根据用户需要分割成多个逻辑网，管理员对分布于各个网段的用户视作在同一逻辑网中进行管理，在网络性能、保护用户投资及向ＡＴＭ过渡方面具有很好的性能。本文对虚拟局域网技术进行综述。     

ATM通信网基本原理概述

简要介绍了通信网的发展状况，通过对ATM通信网的分析与研究，详细描述了ATM通信网的基本概念及其基本原理，特别对虚通路和虚信道的概念、交换、应用做了详尽地阐述。     

一种MPOA边缘设备的研制

ＡＴＭ Ｆｏｒｕｍ提出的局域网仿真（ＬＡＮＥ）技术是一种将传统局域网接入到ＡＴＭ网络的重要方法,以ＬＡＮＥ为基础的ＭＰＯＡ将使ＡＴＭ真正进入企业网,本文提出一种ＭＰＯＡ边缘设备的方案,已经实现了局域网仿真网桥的功能,并且达到了很高的性能。     

ATM local area networks

LAN emulation offers a best-effort, connectionless, packet transfer service at the MAC sublayer, implemented on top of a connection-oriented ATM network LAN emulation using switched virtual connections requires address resolution to locate the destination end station followed by connection establishment to the resulting ATM address. Address resolution may be implemented by a broadcast technique or by an address server. The broadcast method is the simplest for small networks but a combination of both is probably better. The use of the MAC address to identify an end station, with dynamic binding to its current physical location in the ATM network, allows the ATM LAN segment to be viewed as a virtual LAN. The virtual LAN model permits end stations to move and change physical location while maintaining connection to the same ATM LAN segment. This greatly simplifies the management of large data networks