Design alternatives for wireless local area networks

In this paper an overview of the wireless local area network (LAN) area is provided. The two types of wireless LAN topologies used today, infrastructure and ad hoc, are presented. The requirements that a wireless LAN is expected to meet are discussed. These requirements impact on the implementation of both the Physical and MAC layer of a wireless LAN. The unique characteristics of wireless physical layers are discussed and the five technology alternatives used today are presented. MAC layer issues are discussed and the two existing standards, IEEE 802.11 and HIPERLAN 1, are examined. Polling‐based MAC protocols (RAP, GRAP) are also reviewed. Finally, an introduction is made to wireless technologies that interact with WLANs, such as personal area networking (PAN) and wireless ATM and an overview of HIPERLAN 2, a WLAN using ATM technology, is provided. Copyright © 2001 John Wiley & Sons, Ltd.     

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.     

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。     

一种校园范围无线移动交互网的结构

本文提出了一种支持大型大学校园中移动通信的网络结构，设计允许每个移动宿主机在校园中自由漫游时保持传输连接性。设计结合了无线局域网和高速异步转移模式交换技术，提供了一个有处理大量移动宿主同时运动的有充足集合带宽的无线通信系统。     

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     

无线宽带通信系统

本文重点介绍无线宽带通信系统的宽带接入技术如无线LAN、无线 ATM、LMDS 和MMDS。另外-还介绍了以 TD-MA 和 CDMA 为基础的多媒体无线通信中的新技术,如自适应调制、OFDM/SS 等。     

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.     

无线宽带通信系统及应用

无线通信正处于从窄带传输向宽带传输过渡的发展时期。苯文简单介绍无线局域网、宽带综合数字网、第三代移动通信系统和无线ATM网络几种无线宽带通信系统及其应用。     

试论计算机网络技术在电子信息工程中的应用探究

为促进电子信息工程更好地发展,文章对计算机网络技术在电子信息工程中的应用进行研究。首先,阐述了计算机网络技术和电子信息工程相关概述,然后介绍了计算机网络技术在电子信息工程中的应用主要途径,最后提出了L AN网络、ATM网络、无线网络这几个具体应用实例,希望能够提供给相关人员一些参考。     

局域网接入ATM网的一种方案及其实现

将传统的局域网接入ＡＴＭ网,利用ＡＴＭ网进行互通,不仅可以提高局域网互通遥性能,而且对于保护用户已有的诉发展和也非常有利。本文提出了将局域网接入ＡＴＭ网,利用ＡＴ 进行互通的一种方案,地方案的具体实施进行了研究。     

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     

浅谈虚拟局域网技术

详细介绍了计算机局域网冲突域和广播域的基本知识，可以使用虚拟局域网技术来隔离广播域。并又介绍了VLAN干线(Trunk)的基本知识以及几种常用的VLAN Trunk协议，简单分析了VLAN交换机对VLAN信号数据的处理过程。     

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。     

VLAN的核心技术──VTP

文章在简单介绍ＶＬＡＮ概念和优势的基础上,进一步介绍ＶＬＡＮ中应用最广泛的虚网络隧道协议（ＶＴＰ）技术,并着重详细介绍Ｃｉｓｃｏ公司的ＶＴＰ。     

ATM网络技术在局域网中的应用

ＡＴＭ网络技术是宽带综合业务数字网络（Ｂ－ＩＳＤＮ）的关键技术，随着多媒体技术与多功能个人计算机技术的高速发展，促进了这一技术在计算机局域网络中的广泛应用，本文就ＡＴＭ网络技术在局域网中的应用进行详细综述。     

Modelling ARQ for a High-Speed ATM-Based Wireless LAN

An Automatic Repeat Request (ARQ) scheme is proposed for a wireless ATM LAN based on the MEDIAN concept. Simulations have been performed to demonstrate the consequences of ARQ inclusion in terms of required buffer capacity and resulting cell end-to-end delay. In particular, the behaviour of the ARQ-enhanced system for real-time traffic under non error-free conditions has been examined. The main result of the simulations is that, due to specific properties of the MEDIAN wireless ATM LAN, the proposed ARQ scheme is suitable for real-time ATM services, while yielding virtually error-free links. Next to low cell delay, it features low overhead and low processing complexity whereas it can be readily combined with a simple and efficient MAC scheme.     

基于ATM虚拟局域网的网络拓扑搜索

动态显示网络系统的拓扑图是网络管理系统的基本功能,目前常见的拓扑搜索算法大部分都是基于网络层的,不能对链路层的动态网络拓扑进行搜索且不能发现和管理虚拟网。提出一种利用SNMP协议、ICMP 协议和ARP协议三种协议相结合的网络拓扑搜索算法,发现ATM网络的链路层网络拓扑和提取ATM虚拟网的配置信息。最后,以哈工大通信所的某一子网（ATM虚拟局域网）为例,对此算法进行了验证。     

无线局域网通信安全问题探讨

随着通信技术的发展和进步,无线局域网技术也有了突飞猛进的提升。无线局域网以其具备灵活性、移动性、易扩展性等特点而受到了越来越多用户的青睐。随之而来的无线局域网通信安全问题也越来越多,也越来越受到用户的关注。围绕无线局域网的安全问题,对无线局域网的安全技术、常见安全威胁因素进行细致透彻的分析。同时,还给出无线局域网安全的一些对策性措施,以确保无线局域网的安全、正常运行。     

Wireless ATM networks: technology status and future directions

The concept of “wireless ATM” (WATM), first proposed in 1992, is now being actively considered as a potential framework for new-generation wireless communication networks capable of supporting integrated, quality-of service (QoS) based multimedia services. In this review paper, we outline the technological rationale for wireless ATM, present a system-level architecture, and discuss key design issues for both mobile ATM switching infrastructure and radio access subsystems. The WATM radio access layer issues covered in this paper include: spectrum allocation; spectrum etiquette; modem technology; and medium access/data link control (MAC/DLC) protocols. Mobile ATM aspects such as ATM signaling extensions for handoff control, location management, and mobile QoS control are discussed. A summary of current wireless/mobile ATM technology development and standardization status is given, including an outline of our WATMnet prototype. The paper concludes with a discussion of future directions for wireless ATM technology such as Internet protocol (IP) integration and mobile multimedia terminals/applications