Data communication in ATM networks

An increasing number of customers require LAN access with high bandwidth and low delay over long distances. To satisfy these needs, several high-speed network techniques have been developed. Asynchronous transfer mode (ATM) is superior compared to other networking technologies, as it offers high bandwidth and is scalable in the sense that the bandwidth capacity of an ATM system is not fundamentally limited to the technology itself. Initial ATM installations will operate as subnetworks of existing networks and MAC layer protocols. One of the main challenges in ATM is the transparent support of existing connectionless LAN services. Several activities have been launched within international standard bodies and forums to specify ways of providing data communication services over ATM. Most notable examples are Switched Multimegabit Data Service (SMDS) and the similar Connectionless Broadband Data Service (CBDS) supported mostly by public network service providers. But also other approaches such as IP over ATM, and LAN emulation that show more adherence to the existing local and campus area networking paradigms. The article presents the requirements and architecture of the LAN emulation service. It describes the alternative methods for carrying IP packets over ATM, a public broadband service architecture and CBDS. The traffic management aspects of the data communication services are also discussed     

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     

ATM技术在校园网中的实时性应用

讨论了ＡＴＭ论坛关于局域网仿真技术的基本思想及其协议体系的工作过程，并介绍了利用局域网仿真技术在校园网中应用ＡＴＭ技术实现视频传输的方法。     

ATM网络上的LAN仿真技术

本文比较ＡＴＭ网络和ＬＡＮ的区别。对ＡＴＭ局域网技术作了论述，内容包括ＡＴＭＬＡＮ仿真的组成、工作原理及其特点。     

Wireless ATM network architectures

Emulated LAN technology supports mobile hosts in wireless ATM networks. This paper introduces virtual LAN (VLAN) services using ATM LAN emulation technology which operates on a client/server model. One of the attractive features of the VLAN is the capability to group users into a broadcast domain. The focus of this paper is the issue of supporting quality of service to mobiles in a wireless ATM network. Copyright © 2001 John Wiley & Sons, Ltd.     

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     

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     

Overview of implementing ATM based enterprise local area networkfor desktop multimedia computing

The authors discuss important implementation issues in an ATM-based enterprise network, and propose possible migration strategies for the smooth introduction of ATM into the desktop computing environment. They present the ATM traffic service classes and the associated traffic management functions. The authors cover the latest ATM forum standardization efforts on traffic management functions and LAN emulation. Finally, they discuss how to seamlessly support the existing transport control protocol (TCP)/Internet protocol (IP) in an ATM environment     

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。     

ATM LAN emulation

Many of the most common protocols at layers two (media access), three (network), and above expect to operate over broadcast media such as IEEE 802.3/Ethernet or IEEE 802.5/token ring. LAN emulation provides a widely applicable means for transitioning these protocols to the connection-oriented ATM environment. A combination of centralized and distributed intelligence allows a star-plus-mesh topology of ATM virtual circuits to emulate broadcast media, while providing most of the advantages of connection-oriented media     

用卫星ATM技术互连LAN/MAN

介绍了一般的卫星ATM网络互连单元,重点讨论了互连LAN／MAN的ASIU的结构,并指出了设计LAN／MAN互连技术应该考虑的基本问题,最后指出用卫星ATM实现LAN／MAN互连所面临的挑战。     

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     

Reconfigurable ATM switch fabrics using traffic history

An ATM switch fabric which is capable of being reconfigured based on the statistics of a previous time period, is introduced. Taking under consideration the strong correlation between ports in a campus or LAN ATM switch, the proposed architecture exhibits improved performance. We prove the performance improvement, by applying data collected from a campus production ATM switch onto our proposed architecture     

Traffic management for ATM local area networks

Asynchronous transfer mode (ATM) is the first switching technology to be capable of supporting circuit switching and packet switching within a single integrated switching mechanism. This was one of the research goals that led to the development of ATM. Considerable progress has already been made in implementing constant bit-rate services, similar to conventional circuit switching, over ATM. The authors briefly consider how to support LAN emulation over an ATM network and then explore how to offer the dynamic bandwidth sharing in the local area. Considerable progress has already been made in implementing constant bit-rate services, similar to conventional circuit switching, over ATM. However, the bursty nature of data traffic requires dynamic bandwidth sharing similar to packet switching, and this is still under investigation     

Design and applications of ATM LAN/WAN adapters

ATM networks are today operational, both as backbones for existing LAN technologies and as commercial wide-area multiservice networks. Still, in the early deployment of multi-site ATM networks, a number of difficulties have arisen out of the differences between the service definitions in local ATM networks and long-distance carrier networks. In particular, the adaptation of LAN emulation protocols relying on switched, best-effort connections to the first generation of ATM WAN services turned out to require the introduction of specific functions. In this paper, we study and discuss the nature of these adaptation functions which include peak rate shaping in order to comply with the traffic contract at the public UNI, efficient buffering and selective cell discarding to optimize the performance of end-to-end data protocols and fairness mechanisms to improve resource sharing. We describe a flexible hardware platform which enabled a quick prototyping of these functions. It provides on-board support for efficient cell processing and for associated functions (rate control, buffering, etc.). The use of a cell processor enables a software-only implementation of the ATM cell handling, yielding short development times and easy debugging while being compatible with an operation at line speeds up to 155 Mbit/s. We finally give examples and measurements of the use of the adapters in LAN/WAN interworking situations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Broadband Island interconnection via satellite—performance analysis for the race II—catalyst project

The use of communication satellites as a possible way of offering broadband island interconnectivity appears to be a very attractive option, as it will enable the provision of an all-digital, transparent service to a number of ATM islands spanning a wide area, accommodating efficiently a variety of traffic demands. The CATALYST Project (RACE II/R2074) is an attempt to demonstrate the applicability and compatibility of satellite technology with the terrestrial BISDN. In this paper we present an overview of the project and focus on an initial study of the expected user performance through the CATALYST network. Our analysis is based upon mathematical and simulation models and describes the end-system to end-system transfer delay for given message lengths. The protocol profiles assume a mix of Novell NetWare and Network File System client/server architectures, which are supported by either the IEEE 802.3/Ethernet or fibre distributed data interface LANs, which are themselves linked via LAN/ATM/satellite interface units. Areas of further investigation, and the implication of our analysis on the actual network architecture, are discussed.     

ATM局域网仿真技术

ＡＴＭ局域网仿真技术是由ＡＴＭ论坛提出的一种利用ＡＴＭ网络支持数据通信业务的方法。本文首先简介了引入此项技术的背景，继而分析了ＡＴＭ局域网仿真的基本思想以及仿真局域网的协议体系，网络配置，功能单元与连接种类等基本概念，并详细分析了ＡＴＭ局域网仿真中各项协议规程的工作机制。     

Experimental demonstration of an improved EPON architecture using OFDMA for bandwidth scalable LAN emulation

We propose and demonstrate an improved Ethernet passive optical network (EPON) architecture supporting bandwidth-scalable physical layer local area network (LAN) emulation. Due to the use of orthogonal frequency division multiple access (OFDMA) technology for the LAN traffic transmission, there is no need to change the existing EPON architecture. Only one receiver at each optical network unit (ONU) is required to detect both LAN traffic and EPON downstream traffic, which makes the proposed system simple and cost-effective. Moreover, flexible assignment of LAN traffic bandwidth is realized by allocating different number of subcarriers or using different modulation formats. The 250 Mb/s 4-quadrature amplitude modulation (4-QAM) and 500 Mb/s 16-QAM OFDM LAN traffic are successfully emulated with the EPON traffic in our experiment.     

A proposal of an ATM wireless access system for tetherless multimedia services

This paper proposes an ATM wireless access system for tetherless multimedia services. The proposed system is intended to provide ATM-based high-speed transmission capability for tetherless multimedia services by wireless media in private LAN/WAN environments as well as public environments. To enable high-speed transmission, this paper proposes the utilization of the SHF band taking advantage of its wide frequency spectrum availability. However, the propagation feature of the SHF band limits the wireless terminal mobility in the proposed system compared with current cellular phone systems. This paper discusses the concept and system architecture of the proposed ATM wireless access system, including its ATM transport based on ATM/TDMA conversion using a time stamp scheme.     

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