关于局域网英文文章的翻译 急求各位帮忙!Characteristics of LANsThe main Characteristics of a LAN include its throughput,delays,wiring type and distances,security,and reliability.We discuss these characteristics below.We then compare t

关于局域网英文文章的翻译 急求各位帮忙!Characteristics of LANsThe main Characteristics of a LAN include its throughput,delays,wiring type and distances,security,and reliability.We discuss these characteristics below.We then compare t
关于局域网英文文章的翻译 急求各位帮忙!
Characteristics of LANs
The main Characteristics of a LAN include its throughput,delays,wiring type and distances,security,and reliability.We discuss these characteristics below.We then compare the characteristics of major LANs.
Throughput
The throughput is the average total transmission rate when the LAN is heavily loaded by many nodes.
In a shared LAN,the throughput is a fraction of the rate of the transmitters.This fraction is called the efficiency of the MAC protocl.For insyance,a network that uses a MAC protocol with an efficiency oh 65 percent and 10-Mbps transmitters has a throughput of 6.5 Mbps.These values are typical for a shared 10-Mbps Ethernet.The throughput of a token ring network and that of FDDI are close to their thransmission rate.
Latency
The latency is the time a packet takes froms its arrival at anetwork interface until it reaches the destination node.We explain in Section 4.8that this latency is almost aiways less than a fraction of a second and is often much smaller.
Wiring Type and Distance
Some LANs use twisted wire pairs,others use optical fibers,Older LANs and installations in special environments use coaxial cables.The maximum length of the connections depends on the LAN and on the techanology.Typical values are 100 m for twisted pairs and a few kilometers for multimode fibers.
Security
Anoptical fiber is more difficult to tap into than a twisted pair,which improves the “physical”security.However,eavesdroppers rarely need to tap directly into a link to gain access to information.A more common attack is to use one of the computers attached on the LAN and configure it to read all the packets that travel on the network(this is called snooping).If sensitive pieces of information such as user passwords are transmitted in the clear(nonencrypted),then the eavesdropper obtains entry points into computers.As a rule,a switched LAN is more secure than a shared LAN because a computer on such a network sees only the packets intended for it.
Reliability
We depend increasingly on networks.Accordingly,reliability becomes more essential.As we mentioned in the opening remarks of this chapter,FDDA is designed to survive a link or node failure.An Ethernet keeps on working when some of its nodes or links fail.Atoken ring network can be wired with bypass electronics to have a similar reliability.


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希望帮忙的朋友不光是用GOOGLE翻译来的
因为那样带很多错误 起码修改掉啊 谢谢大家!

关于局域网英文文章的翻译 急求各位帮忙!Characteristics of LANsThe main Characteristics of a LAN include its throughput,delays,wiring type and distances,security,and reliability.We discuss these characteristics below.We then compare t
局域网的特点
局域网的主要特点包括它的吞吐量,延迟,线路类型和距离,安全和可靠性.
下面我们就讨论一下这些特点.然后,我们把一些主要局域网的特点作个比较.
吞吐量
吞吐量是指当局域网由于大量的节点而负载沉重时,它的平均总传输速率.
在一个共享网络中,吞吐量是指发射机的速率的几分之一.这个几分之一的速率就是所谓MAC协议的效率.例如,一个网络使用的是效率为65 ％、发射机速率为10 - Mbps的MAC协议,那么这个网络的吞吐量就是6.5 mbps.这些观念是吞吐量为10 – Mbps的共享以太网的典型特征.令牌网和FDDI的速率和以太网的传输率接近.
潜伏期
潜伏期是数据包从抵达一个网络接口,到抵达目的地节点,所需要的时间.我们在4.8节做了解释,这个潜伏期几乎总是不到几分之一秒,并且常常要小得多.
布线类型和距离
一些局域网使用双绞线,一些使用光学纤维,老局域网和特殊环境中的装置使用同轴电缆.连线的最大长度取决于该局域网和技术.一般意义上,双绞线是一百米,多模光纤是几千米.
安全
anoptical纤维比双绞线难连接,这提高了“物理”安全.但是 ,窃听者几乎不需要直接连到某一链接就能获得信息路径.一个更为常见的攻击是利用连在局域网上的某一台计算机,对它进行配置,然后读取所有的在该网络上传输的数据包（这就是所谓的窥探） .如果明确地传送了敏感信息（非加密）,比如用户密码,那么窃听者就取得了侵入电脑的进入点.一般说来,交换局域网比一个共享网络更安全,因为连这种网络上的计算机只能收到它所需要的数据包.
可靠性
我们越来越依赖网络.相应地 ,可靠性也变得更加重要.正如我们在这一章的开场白中提到的,FDDA是为了让网络在某一链接或节点出了问题时仍能运行而设计的.当以太网的某些节点或链接出问题时,它仍然可以继续正常运行.令牌环网可通过与绕道电子环绕达到类似的可靠性.