1、Lesson 16Networking Hardware教学课件教学课件 Networking hardware includes all computers，peripherals，interface cards and other equipments needed to perform dataprocessing and communications within the network.File Server A file server stands at the heart of most networks.It is a very fast computer with a lar
2、ge amount of RAM and storage space，along with a fast network interface card.The network operating system software resides on this computer，along with software applications and data files that need to be shared.1 Workstation All user computers connected to a network are called workstations.A typical
3、workstation is a computer that is configured with a network interface card，networking software，and the appropriate cables.2 Workstations do not necessarily need floppy disk drives because files can be saved on the file server.Almost any computer can serve as a network workstation.backback教学课件教学课件 Ne
4、twork Interface Card The network interface card（NIC），also called network adapter，provides the physical connection between the network and the computer workstation.Most of them are internal，with the card fitting into an expansion slot inside the computer.3 Some computers，such as Mac Classics，use exte
5、rnal boxes which are attached to a serial port or a SCSI port.Laptop computers can now be purchased with a network interface card built-in.The network interface card is a major factor in determining the speed and performance of a network.It is a good idea to use the fastest network card available fo
6、r the type of workstation you are using.They are usually purchased separately from a computer，although many computers（such as the Macintosh）now include an option for a pre-installed network interface card.backback教学课件教学课件 Switch Switch，also called hub，is a device that provides a central connection p
7、oint for cables from workstations，servers，and peripherals.In a star topology，twistedpair wire is run from each workstation to a central switch/hub.Most switches are active，that is they electrically amplify the signal as it moves from one device to another.4 Switches no longer broadcast network packe
8、ts as hubs did in the past，they memorize addressing of computers and send the information to the correct location directly.Switches are sold with specialized software for port management.backback教学课件教学课件 Repeater Since a signal loses strength as it passes along a cable，it is often necessary to boost
9、 the signal with a device called a repeater.5 The repeater electrically amplifies the signal it receives and rebroadcasts it.Repeaters can be separate devices or incorporated into a concentrator.They are used when the total length of your network cable exceeds the standards set for the type of cable
10、 being used.6 A good example of the use of repeaters would be in a local area network using a star topology with unshielded twisted-pair cabling.The length limit for unshielded twistedpair cable is 100 meters.The most common configuration is for each workstation to be connected by twisted-pair cable
11、 to a multi-port active concentrator.The concentrator amplifies all the signals that pass through it allowing for the total length of cable on the network to exceed the 100 meter limit.7backback教学课件教学课件 Bridge A bridge is a device that allows you to segment a large network into two smaller，more effi
12、cient networks.If you are adding to an older wiring scheme and want the new network to be up-to-date，a bridge can connect the two.A bridge monitors the information traffic on both sides of the network so that it can pass packets of information to the correct location.Most bridges can“listen”to the n
13、etwork and automatically figure out the address of each computer on both sides of the bridge.The bridge can inspect each message and，if necessary，broadcast it on the other side of the network.The bridge manages the traffic to maintain optimum performance on both sides of the network.You might say th
14、at the bridge is like a traffic cop at a busy intersection during rush hour.It keeps information flowing on both sides of the network，but it does not allow unnecessary traffic through.8 Bridges can be used to connect different types of cabling，or physical topologies.They must，however，be used between
15、 networks with the same protocol.backback教学课件教学课件 Router Router，also called gateway in earlier days，translates information from one network to another；it is similar to a super intelligent bridge.Routers select the best path to route a message，based on the destination address and origin.The router ca
16、n direct traffic to prevent head-on collisions，and is smart enough to know when to direct traffic along back roads and shortcuts.9 While bridges know the addresses of all computers on each side of the network，routers know the addresses of computers，bridges，and other routers on the network.Routers ca
17、n even“listen”to the entire network to determine which sections are busiestthey can then redirect data around those sections until they clear up.If you have a school LAN that you want to connect to the Internet，you will need to purchase a router.In this case，the router serves as the translator betwe
18、en the information on your LAN and the Internet.It also determines the best route to send the data over the Internet.Routers can direct signal traffic efficiently，route messages between any two protocols across fiber optic，coaxial，and twisted-pair cabling.backback教学课件教学课件Key Words&TermsAdapter 适配器Br
19、idge 网桥Concentrator 集中器Configuration 配置Interface 接口Intersection 交叉点laptop computer 笔记本电脑optimum performance 最佳性能Peripheral 外围设备Port 端口Repeater 中继器Router 路由器Server 服务器Switch 交换机Topology 拓扑Workstation 工作站backback教学课件教学课件AbbreviationsNIC（Network Interface Card）网络接口卡SCSI（Small Computer System Interface）
20、小型（计算）机系统接口UTP（Unshielded Twisted Pair）非屏蔽双绞线backback教学课件教学课件Notes 1 The network operating system software resides on this computer，along with software applications and data files that need to be shared.本句中的介词短语along with的意思是“连同一起”，在句中与the network operating system software作并列主语。译文：网络操作系统软件连同需要被共享的数据
21、文件和应用软件一起存在于这台计算机上。2 A typical workstation is a computer that is configured with a network interface card，networking software，and the appropriate cables.本句表语是由that引导的定语从句充当，从句中的be configured with的意思是“用配置”。译文：一个典型的工作站是一台配置了一块网卡、网络软件和合适电缆的计算机。3 Most of them are internal，with the card fitting into an e
22、xpansion slot inside the computer.句中with引导的短语作伴随状语。译文：大部分网卡是内置的，卡适合计算机内部的扩展槽。backback教学课件教学课件Notes 4 Most switches are active，that is they electrically amplify the signal as it moves from one device to another.本句是由as引导的伴随状语，句中one device和another是指一台交换机和另一台交换机。译文：大部分交换机处于激活状态，也就是说它们随着信号从一台设备移到另一台设备时将信
23、号放大。5 Since a signal loses strength as it passes along a cable，it is often necessary to boost the signal with a device called a repeater.本句是由since引导的原因状语从句，从句中又包含一个由as引导的伴随时间状语。译文：由于信号经过电缆时强度损失，所以用一个叫中继器的设备增强信号经常是很必要的。backback教学课件教学课件Notes 6 They are used when the total length of your network cable
24、exceeds the standards set for the type of cable being used.本句是由when引导的时间状语从句。译文：当网络线缆的总长度超过正被使用的线缆的标准设置时，中继器被使用。7 The concentrator amplifies all the signals that pass through it allowing for the total length of cable on the network to exceed the 100 meter limit.本句是现在分词allowing引导的结果状语从句。译文：集中器扩大通过它的所
25、有信号，这样就允许网络上线缆的长度超出100米的限制。backback教学课件教学课件Notes 8 It keeps information flowing on both sides of the network，but it does not allow unnecessary traffic through.本句中的keep doing的意思是“连续不断做某事”。译文：网桥使两边网络的信息保持流动，但是它不允许不需要的信息通过。9 The router can direct traffic to prevent head-on collisions，and is smart enoug
26、h to know when to direct traffic along back roads and shortcuts.本句中的head-on的意思是“正面的”；“beadjenoughto do”结构表示“足够怎么样，以至于”。译文：路由器能够疏导交通以防止正面冲突，并且智能到知道什么时候指导交通沿着后路走和抄近路走。backbackExercisesTranslate the following phrases into English.1网络硬件2文件服务器3网络接口卡4最佳性能5局域网6信号强度backbackExercisesTranslate the following s
27、entences into Chinese.1A bridge is a device that allows you to segment a large network into two smaller，more efficient networks.2The length limit for unshielded twisted-pair cable is 100 meters.3Switch provides a central connection point for cables from workstations，servers and peripherals.4A file s
28、erver stands at the heart of most networks.backbackExercisesIdentify the following to be true or false according to the text.1Repeaters are also called hub.2A bridge can be used between networks with different protocol.3Routers know how to direct data through selecting paths.4Both bridges and Router
29、s can be used to connect across different transmission media.Filling in each of the following blanks according to the text.1All user computers connected to a network are called .2 are a major factor in determining the speed and performance of a network.3Switches are sold with specialized software for_.4A bridge is a device that allows you to_a large network into two smaller，more efficient networks.backback
