02-4 2.4 Network Architecture.pptx

第1页：2.4 生词表

第2页：2.4 生词表（续）

第3页：2.4 常用短语

第4页：网络体系结构描述计算机网络

Network architecture describes how computer network is arranged and how computer resources are shared. There area number of specialized terms that describe computer network. Some terms often used with networks are:node,client,server,network operating system,distributed processing and host computer.网络体系结构描述计算机网络是如何连接以及计算机资源是如何共享的。有一些用来描述计算机网络的专业术语。经常用于网络的术语有：节点、客户机、服务器、网络操作系统、分布处理及主计算机。

第5页：节点是连接到网络的任一设备

节点是连接到网络的任一设备，它可以是计算机、打印机、通信或数据存储设备。客户机是请求和使用其他节点资源的节点。通常情况下，客户机就是用户的微机。Anodeisany device that is connected to a network. Itcouldbea computer,printer,or communication or data storage device Aclientisano de that requests and uses resources available from other nodes. Typically,a client is a user's microcomputer.

第6页：服务器

服务器是和其他节点共享资源的节点。根据所共享的资源，服务器可以被称为文件服务器、打印机服务器、通信服务器或数据库服务器。Network operating system likes Windows,it controls and coordinates the activities between computers on a network. These activities include electronic communication,information,and resource sharing.网络操作系统像Windows，它控制和协调网络中计算机间的活动。这些活动包括电子通信、信息以及资源共享。Aserverisano de that shares resources with other nodes. Depending on the resources shared,it maybe called a fileserver,printerserver,communication server,or database server.

第7页：2.4 网络体系结构 课文要点

语言点分析：句中where引导的是定语从句，用来修饰organizations。在分布式处理系统中，计算能力被分布在不同的地方共享。这类系统在分散型机构中是很常见的，其分开的办公室具有他们自己的计算机系统。这些分开的办公室的计算机系统联网到该机构的主计算机或中央计算机。In a distributed processing system,computing power is located and shared at different locations.[1]Thistypeof system is common in decentralized organizations where divisional offices have their own computer systems. The computer systems in the divisional offices are networked to the organization's main or centralized computer.

第8页：2.4 网络体系结构 课文要点

语言点分析：分词短语working together equally作定语修饰allnodes，分词短语coordinating and supplying all resources作定语修饰specializednodes。Hostcomputer is a large centralized computer,usually a minicomputer or a mainframe.主计算机是大的中央计算机，通常是小型机或大型机。Anetworkmay consist only of microcomputers,or it may integrate microcomputers or other devices with large computers.[2]Networks can be controlled by all nodes working together equally or by specialized nodes coordinating and supplying all resources. Networks maybe simple or complex,self-contained or dispersed over a large geographical area.网络可以是仅仅由微机组成的，或者是微机或其他设备与较大计算机结合起来的。网络可以由一起平等工作的所有节点来控制，或者是由协调和提供所有资源的专用节点控制。网络可以是简单的或复杂的，独立的或分散在大的地理区域内的。

第9页：结构网络可以用几种不同的方式排列或连接

Configuration Anetworkcan be arranged or configured in several different ways. The four principal configurations are star,bus,ring,andhierarchical.结构网络可以用几种不同的方式排列或连接。四种主要的结构是星型、总线型、环型和层次型。Inastarnetwork,a number of small computers or peripheral devices are linked to a central unit. This central unit maybe a host computer or a fileserver. All communications passthrough this central unit. Control is maintained by polling. Thatis,each connecting device is asked whether it has a message to send. Eachdeviceis then in turn allowed to send its message.在星型网络中，一些小的计算机或外部设备被连接到一个中心设备。这个中心设备可以是主计算机或文件服务器，所有的通信都通过这个中心设备。控制是由轮询实现的。也就是说，每一个连接的设备都被询问是否有信息发送，然后每个设备被轮流允许发送其信息。

第10页：星型网络最特殊的优点

One particular advantage of the star form of network is that it can be used to provide a time-sharing system. Thatis,several users can share resources("time")on a central computer. Thestarisa common arrangement for linking several microcomputers to a mainframe that allows access to an organization’sdatabase.星型网络最特殊的优点是它能用于提供分时系统，即几个用户可以在一个中心计算机上共享资源（“时间”）。为了将几个微机连接到大型机上以访问一个机构的数据库，星型结构是常见的排列。

第11页：在总线型网络中

Inabusnetwork,each device in the network handles its own communications control. Thereisno host computer. All communications travel along a common connecting cable called a bus. As the information passes along the bus,it's examined by each device to see if the information is intended for it.在总线型网络中，网络中的每一个设备处理自己的通信控制，该网络中没有主计算机。所有通信沿着被称为总线的公共连接电缆传输。信息通过总线时，被每一个设备检验以判定该信息是否是给自己的。

第12页：当只有几个微机需要连接在一起时

The bus network is typically used when only a few microcomputers are to be linked together. This arrangement is common in systems for electronic mail or for sharing data stored on different microcomputers. The bus network is not as efficient as the star network for sharing common resources.(This is because the bus network is not a direct link to the resource.)However,a bus network is less expensive and is in very common use.当只有几个微机需要连接在一起时，一般使用总线型网络。这种结构常见于发送电子邮件或共享存储在不同微机上的数据的系统。对于共享资源，总线型网络没有星型网络的效率高（这是因为总线型网络不是直接连接到资源上的）。然而，总线型网络不贵而且很常用。

第13页：在环形网络中

Inaringnetwork,each device is connected to two other devices,forming a ring. Thereisno central fileserver or computer. Messages are passed around the ring until they reach the correct destination. With microcomputers,the ring arrangement is the least frequently used of the four networks. However,it is often used to link mainframes,especially over wide geographical areas.在环形网络中，每一个设备被连接到其他两个设备形成环路。环形网络中没有中央文件服务器或中央计算机，信息通过环路直至到达正确的目的地。对于微型机来讲，环形结构是这四种网络当中使用最少的。然而环形网经常被用于连接大型机，尤其在跨度很大的地理区域。

第14页：这些大型机趋向于非常自主的运作

These mainframes tend to operate fairly autonomously. They perform most or all of their own processing and only occasionally share data and programs with other mainframes. Aringnetwork is useful in a decentralized organization because it makes possible a distributed data processing system. Thatis,computers can perform processing tasks at their own dispersed locations. However,they can also share programs,data and other resources with eachother.这些大型机趋向于非常自主的运作，它们完成自己绝大多数或全部的处理任务，偶尔与其他大型机共享数据和程序。环型网络在分散型机构中是很有用的，因为这使得分布式数据处理系统成为可能，即计算机在它们自己分散的位置就可以完成处理任务。然而，它们也可以相互共享程序、数据以及其他的资源。

第15页：层次网络

The hierarchical network consists of several computers linked to a central host computer,just like a star network. However,these other computers are also hosts to other,smaller computers or to peripheral devices. Thus,the host at the top of the hierarchy could be a mainframe. The computers below the mainframe could be minicomputers,andthosebelow,microcomputers.层次网络是由几个连接到中心计算机的计算机构成的，就像星型网络。然而，这些计算机又可以作为其他更小的计算机或外部设备的主机。这样，在层次顶部的主计算机就可能是大型机，在大型机下层的可能是小型机，小型机下层是微机。

第16页：也被称为混合网络——允许各种计算机共享数

The hierarchical network—also called a hybrid network—allows various computers to share databases,processingpower,and different output devices. A hierarchical network is useful in centralized organizations. Forexample,different departments within an organization may have individual microcomputers connected to departmental minicomputers. The minicomputers in turn maybe connected to the corporation’smainframe,which contains data and programs accessible to all.层次网络——也被称为混合网络——允许各种计算机共享数据库、处理能力及不同的输出设备。层次网络适合于集中的机构。例如，一个机构内部的不同部门可以有连接到部门小型机上的单个微机，这个小型机依次可以连接到公司的大型机，公司大型机包含所有机器可以访问的程序和数据。

第17页：策略每一个网络都有协调信息和资源的策略或

策略每一个网络都有协调信息和资源的策略或方法，最常用的网络策略是对等和客户/服务器系统。Strategies Every network has a strategy or way of coordinating the sharing of information and resources. The most common network strategies are peer-to-peer and client/serversystems.

第18页：在对等网络系统中

Ina Peer-to-Peernetwork system nodes can act as both servers and clients. Forexample,one microcomputer can obtain files located on another microcomputer and can also provide files to other microcomputers. Atypical configuration for apeer-to-peer system is the bus network. Commonly used net operating systems are Apple's Macintosh Peer-to-Peer LANs,Novell’sNetwareLite,and Microsoft's Windows for Work groups.在对等网络系统中，节点既可以是服务器也可以是客户机。例如，一个微机可以获得位于另一个微机上的文件，也可以给其他的微机提供文件。对等系统的典型结构是总线型网络。常用的网络操作系统有Apple公司的Macintosh Peer-to-peer LANS、Novell公司的NetwareLite和Microsoft公司的Windows for Work groups。

第19页：使用这类策略有几个优点

There are several advantages to using this type of strategy. The networks are inexpensive and easy to install,and they usually work well for smaller systems with less than ten nodes. As the number of nodes increases,however,the performance of the network declines. Another disadvantage is the lack of powerful management software to effectively monitor a large network's activities. For these reasons,peer-to-peer network are typically used by small networks.使用这类策略有几个优点。这种网络不贵且易于安装，通常较好地工作于节点数小于10个的小系统。然而，当节点的数目增加时，网络的性能就会下降。另一个缺点是缺乏强大的管理软件以有效地监控大的网络活动。由于这些原因，对等网络一般用于小型网络中。

第20页：服务器网络系统使用一个功能强大的计算机来

Client/server network systems use one powerful computer to coordinate and supply services to all other nodes on the network. This strategy is based on specialization. Servernodes coordinate and supply specialized services,and client nodes request the services. Commonly used net operating systems are Novell's Netware,Microsoft's LANand Windows NT.客户/服务器网络系统使用一个功能强大的计算机来协调网络上的其他节点，并提供服务。这一策略是基于专业化的，服务器节点协调和提供专门的服务，客户节点请求服务。常用的网络操作系统有：Novell公司的Netware、Microsoft公司的LAN和Windows NT。

第21页：服务器网络系统的一个优点

One advantage of client/server network systems is their ability to handle very large networks efficiently. Another advantage is the powerful network management software that monitors and controls the network's activities. The major disadvantages are the cost of installation and maintenance.客户/服务器网络系统的一个优点是能够有效地处理大的网络活动。另一个优点是它有强有力的网络管理软件监视和控制网络活动。其主要缺点是安装和维护的费用较高。

第22页：习题2.4 一 判断正误

习题2.4 一 判断正误：根据课文内容判断下列说法正误。

Put“true”or“false”in the brackets for the following statements according to the passage.

1. ()The network architecture describes how a computer network is arranged; the arrangement is called topology.
2. ()In a distributed processing system, computing power is located and shared at the same location.
3. ()Inastar network, each device can require to send message simultaneously.
4. ()Inabus network, as information passes through the bus, every node can receive it.
5. ()With microcomputers, the ring arrangement is the most frequently used of the four networks.
6. ()A hierarchical network is useful in distributed organizations.
7. ()Inapeer-to-peer network system nodes can act as both servers and clients, thatis, the nods can exchange their roles.
8. ()Inaclient/server system, all nodes on the network have equal responsibilities for coordinating the network’s activities.

第23页：习题2.4 二 练习

习题2.4 二 练习：根据课文内容完成下列练习。

Fillinthe blanks according to the passage.

1. Network architecture describes how computer network is__________and how computer resources are________.
2. A______is any device that is connected to a network..
3. Network operating system_________and___________electronic communication, information, and resource sharing.
4. Inastar network, control is maintained by__________.
5. Inaring network, each device is connected to two other devices, forming a_______.
6. Aringnetwork is useful in a______________organization because it makes possible a____________data processing system.
7. _______________network systems use one powerful computer to coordinate and supply services to all other nodes on the network.
8. The most common network strategies are______________and client/server systems.

第24页：习题2.4 三 翻译

习题2.4 三 翻译：将下列单词和短语译成中文。

Translate the following words and expressions into Chinese.

1. distributed processing system
2. network architecture
3. peer-to-peer system
4. strategy
5. hierarchical network
6. host computer
7. peripheral device
8. decentralized organization
9. self-contained
10. configuration