CCNA 2 Chapter 2 V4.0 Answers

1. Which statements correctly identify the role of intermediary devices in the network? (Choose three.)determine pathways for data 确定数据通路initiate data communicationsretime and retransmit data signals 重分发originate the flow of datamanage data flows 管理数据final termination point for data flow2. Select the statements that are correct concerning network protocols. (Choose three.)define the structure of layer specific PDU'sdictate how to accomplish layer functionsoutline the functions necessary for communications between layers limit the need for hardware compatibilityrequire layer dependent encapsulationseliminate standardization among vendors3. What are two functions of encapsulation? (Choose two.)tracks delay between end devicesenables consistent network paths for communicationallows modification of the original data before transmissionidentifies pieces of data as part of the same communicationensures that data pieces can be directed to the correct receiving end device4. What is a primary function of the trailer information added by the data link layer encapsulation?supports error detection 支持错误检测‘ensures ordered arrival of dataprovides delivery to correct destinationidentifies the devices on the local networkassists intermediary devices with processing and path selection5. Which statements correctly identify the role of intermediary devices in the network? (Choose three.)determine pathways for datainitiate data communicationsretime and retransmit data signalsoriginate the flow of datamanage data flowsfinal termination point for data flow6. What is a PDU?corruption of a frame during transmissiondata reassembled at the destinationretransmitted packets due to lost communicationa layer specific encapsulation 一个具体的封装层7. Which characteristic correctly refers to end devices in a network?manage data flowsoriginate data flow 原数据流retime and retransmit data signalsdetermine pathways for data8.Refer to the exhibit. "Cell A" at IP address 10.0.0.34 has established an IP session with "IP Phone 1" at IP address 172.16.1.103. Based upon the graphic, which device type best describes the function of wireless device "Cell A?"the destination devicean end devicean intermediate devicea media device9.Refer to the exhibit. Which three labels correctly identify the network types for the network segments that are shown?(Choose three.)Network A -- WANNetwork B -- WANNetwork C -- LANNetwork B -- MANNetwork C -- WANNetwork A -- LAN10. Which three statements best describe a Local Area Network (LAN)? (Choose three.)A LAN is usually in a single geographical area.The network is administered by a single organization.The connection between segments in the LAN is usually through a leased connection.The security and access control of the network are controlled by a service provider.A LAN provides network services and access to applications for users within a common organization.Each end of the network is generally connected to a Telecommunication Service Provider (TSP).11.Refer to the exhibit. Which networking term describes the data interleaving process represented in the graphic?pipingPDUstreamingmultiplexingencapsulation12. What is the primary purpose of Layer 4 port assignment?to identify devices on the local mediato identify the hops between source and destinationto identify to the intermediary devices the best path through the network to identify the source and destination end devices that are communicating to identify the processes or services that are communicating within the end devices13. What device is considered an intermediary device?1．file serve2.IP phone ptop 4.printer 5.switch14.Refer to the exhibit. Which term correctly identifies the device type that is included in the area B? sourceendtransferintermediary 中间设备15.Refer to the exhibit. What type of network is shown?WANMANLANWLAN16. Which layer encapsulates the segment into packets?physicaldata linknetwork 网络层封装的是数据包transport17. What can be identified by examining the network layer header?the destination device on the local mediathe destination host address 网络层头部封装目的主机的地址the bits that will be transferred over the mediathe source application or process creating the data18. What is the purpose of the TCP/IP Network Access layer?path determination and packet switchingdata presentationreliability, flow control, and error detectionnetwork media control 接入层控制网络媒体the division of segments into packets19. During the encapsulation process, what occurs at the data link layer? No address is added.The logical address is added.The physical address is added. 数据链路层添加一个物理地址The process port number is added.20.Refer to the exhibit. Which set of devices contains only end devices? A, C, DB, E, G, HC, D, G, H, I, JD, E, F, H, I, JE, F, H, I, J21. What is the proper order of the layers of the OSI model from the highest layer to the lowest layer?4physical, network, application, data link, presentation, session, transportapplication, physical, session, transport, network, data link, presentationapplication, presentation, physical, session, data link, transport, networkapplication, presentation, session, transport, network, data link, physicalpresentation, data link, session, transport, network, physical, application22. Which two layers of the OSI model have the same functions as the TCP/IP model Network Access Layer? (Choose two.)34NetworkTransportPhysicalData Link TCP/IP 工作在第一层和第二层Session。

培训讲义1培训讲义2000@1632002 年5 月上海2目录前言 (5)第一章介绍 (8)1.1 什么是 (8)1.2 学习内容及目标 (8)1.3 学习基础 (9)1.4 考试申请 (9)第二章课程介绍 (11)2.1 课程特点 (11)2.2 课程目标 (11)2.3 预备知识 (12)2.4 课程安排 (12)2.5 推荐书目 (13)第三章 (15)3.1 提出背景 (15)3.2 模型的提出意义 (16)3.3 模型 (17)3.3.1 物理层 (18)3.3.2 数据链路层 (19)3.3.3 网络层 (20)3.3.4 传输层 (21)3.3.5 会话层 (23)3.3.7 应用层 (24)3.4 数据封装 (25)3.5 模型 (26)3.6 产品选择 (26)第四章a (27)4.1 路由器 (27)4.1.1 路由器硬件构成 (28)4.2 ( ) (29)4.2.1 界面 (30)4.2.2 常用命令 (30)4.2.3 外部配置方式 (32)4.2.4 常用快捷键 (32)4.2.5 (32)4.2.6 (33)4.2.7 口令恢复 (34)32 (36)第五章1900 (36)5.1 ()技术 (37)5.2 的三个功能 (38)5.3 () (40)5.3.1 的步骤 (41)5.3.2 (42)5.3.3 的转发模式 (43)5.4 的配置 (44)5.5 虚拟局域网 (44)5.5.1 什么是? (44)5.5.2 (帧封装技术) (46)5.5.3 () (47)5.5.4 (49)5.5.5 配置 (50)3— (52)第六章 (52)6.1 概述 (52)6.2 地址划分 (56)6.2.1 基本知识 (56)6.2.2 子网划分 (59)6.2.3 一些配置 (59)第七章 (61)7.2 路由分类 (63)7.3 路由协议分类 (65)7.3.1 (65)7.3.2 最佳路由选择 (66)7.3.3 维护路由表 (66)7.3.4 的形成与克服 (67)7.3.5 配置和 (68)第八章 (70)8.1 为什么要使用 (70)8.2 分类 (70)8.3 配置原则 (71)8.4 正确使用 (71)8.5 配置 (72)8.5.1 使用控制访问 (74)4第九章 (75)9.1 广域网 (75)9.1.1 几种常用术语 (76)9.2 几种典型第二层封装协议 (76)9.3 (79)9.3.1 和 (80)9.4 配置 (81)第十章 (82)10.2 三种协议 (84)10.3 的两种接入方法 (84)10.4 配置 (84)10.5 配置按需拔号路由 (85)10.5.1 配置的步骤 (85)第十一章 a (87)11.1 (87)11.2 术语 (88)11.3 常用查看命令 (94)第十二章实验部分 (95)5前言写一本适合喜欢网络新手的培训讲义一直是我的一个想法我接触网络有7 个年头了从最初的3.1下的网络建设开始直到今天的以设备为主的大型网络中间经历了与大多数人一样的学习过程95 年在大学上计算机网络专业的研究生时由于自己本科学的是卫星通信可以说当时对计算机网络一点感觉都没有当初计算机普及率跟现在是不能相提并论的更别说网络了那时能在导师手下独用一台486已经可以在同学中招摇过市了记得有一次在实验室导师让我将一个文件从另外一台机器拷到他的机器上我折腾了半天也不会用脑子里面的计算机网络知识除了其它一点都没有帮上忙当时我就觉得为什么在书本上学的那么多的理论知识可到实际生活中却一点都用不上也许这也正是许多网络新手最初对网络的感觉――神秘不可捉摸看到许多介绍网络知识的书本感到它们要么是面广泛泛而谈看完之后原来是自己都会的东西要么就是点深讲了一大通理论和复杂的算法后除了空白还是空白98 年参加单位超大型网络建设接触了大量网络设备6尤其是路由器喜欢没有别的原因就是因为简捷好用可靠而且它也是一个将理论转换为实际的理想平台对了我不是任何形式的代理我说的只是自己摸索设备的一些心得2001 年年初与一个朋友聊天得知他已是什么了又告诉我什么是以前也了解一些认证情况但从来没有一个实际的全面的认识于是下定决心去考触摸一下认证的感觉过了之后感觉到对自己的工作确实很有帮助提高和纠正了自己在工作中的经验好吧再去考也过了我从到全部是自己学习的只是从网上了许多学习资料而且也得到了许多人的帮助细化了将许多深奥的理论以浅显的方式表述出来理顺和加深了自己对一些网络概念的理解这里我觉得看英文版书要比看中文版书好当然是我的一个目标但是费用是我的一个最大问题我相信许多网络人的共同目标就是何时拿下与朋友们煮酒论英雄!这是一句美国西点军校的名言它告诉我们要勇敢地面对明天因为最困难的日子都过去了还有什么不能坚持下去希望就在前方我想这就是我们在寒冷的冬天的最好的慰籍在此献给所有同行们7我在一个网络培训中心做过讲师用的是教材是公司的幻灯片形式的讲义它没有展开网络知识只是归纳出重要概念和纲目来从严格意义上讲它不能算是一个好的教材所以我结合自己的实际情况和已有的一些资料写了这本讲义由于网络知识涉及面广内容新其中一定有不少不当之处和表达不清的地方希望大家给我批评指正就当是给一个朋友提个醒2002 年5 月25 日上海8第一章介绍1.1 什么是认证分为三个层次分别为认证网络工程师() 初级认证—认证资深网络工程师中级认证—认证互联网工程师() 高级认证1.2 学习内容及目标从学习内容上可分为四大部分主要内容包括网络协议理论基础协议广域网协议局域网广域网解决方案涉及到的内容均为目前中小型网络解决方案中所必需的知识通过认证的工程师将具备如下技能• 安装配置以及运行500 个网络节点规模的网络系统• 能够胜任的路由器管理能力9• 已获得全球500 大企业的认可和接受• 是各跨国公司和电子商务企业所急需的人才• 移民及出国留学可获得技术加分是升职加薪寻找丰厚工作待遇的有力凭证1.3 学习基础只要具有一定的英语基础和基本的计算机应用知识拥有高中以上的学历就可开始的学习课程的特点是入门的起点不高但随着课程的逐步深入您将学习到更高层次的知识与技能最后成为计算机网络应用的高级人才因此是否具有渴望掌握先进网络知识的愿望积极的学习态度以及希望从事计算机网络行业成为高级网络人才的理想是能否学会课程的前提条件当然如果具有良好的基础会达到事半功倍的效果1.4 考试申请至少提前一天个人到考试中心申请认证考试1.5 目标人群10对产品或网络不太熟悉的客户渠道经销商对产品和服务不太了解的网络技术人员中小型企业网的网络管理员在中大型企业中执行桌面支持工作的网络技术支持人员为小型企业环境提供网络设备安装和第一线支持的网络技术人员希望获取授证的人员希望获取授证的人员11第二章课程介绍2.1 课程特点介绍在多协议互连网络中配置交换机和路由器所需的概念命令和相关实验通过讲解讨论演示练习(和实验设计)能够为中小型企业确定和推荐最佳解决方案该课程提供技术支持人员所需的关于产品安装配置以及故障排除方面的知识2.2 课程目标• 确定集线器以太网交换机或路由器的最佳使用环境• 确定多种互连的设备的网络中的地址协议以及链路连接状态• 根据给定的网络设计指标互连交换器和路由器• 在路由器上正确配置各种路由协议和广域网技术• 配置访问列表对网络设备或网段的访问权限以及常规网络流量实施控制12• 检查交换机路由器及其网络服务和协议的运作情况是否符合给定的网络指标2.3 预备知识参加课程应具有基本的网络概念并且接触过或网络建议学员最好具有网络环境里的工作经验详细的预备知识包括对如下内容的基本了解• 常用的网络术语和拓扑结构• 基本的网络设备例如集线器网桥路由器交换机)• 二进制和十六进制的运算及与十进制数字转换( 最好掌握但并非必须要求)• 网络模型• 访问或• 应用95 运行多个应用程序2.4 课程安排课程时间为5 天或10 个晚上具体如下13课次内容备注第一晚1,2 介绍第一天第二晚3,4(操作命令)课程介绍I n t e r n e t 介绍网络基础知识回顾O S I 原理T C P / I P 原理等第第三晚5(路由器组成)二天第四晚6(交换机的工作原理)网络互连配置I O S 基本命令网络环境管理的基本命令; 交换机基本概念第第五晚7()三天第六晚8 地址划分交换机V L A N T C P / I P 的配置T C P / I P 的配置续第第七晚9 路由协议四天第八晚10R I P I R G P O S P F 路由协议工作原理第九晚12,13,14(第五天第十晚实验(实验配置见图) W A N 的配置I S D N 的配置帧中继的配置等2.5 推荐书目在考试之前推荐几本好一点的学习用书结合会达到事半功倍的效果141 思科网络技术学院教程(上,下册)78 元中文版人民邮电出版社特别适合初学者内容通俗易懂3 考试认证考试(640-507)指南83 元(含光盘)中文版人民邮电出版社的考试用书内容覆盖了考试的全部内容也有许多内容已经超出了的考试要求4 因为考试是全英文的所以最好在考试之前再仔细将研读英文版用书目前较流行的英文版用书有3.0 封面有一个骑士头像5 3.1―― 路由交换模拟强烈推荐能完成学习中遇到的绝大部分命令6 3――考试模拟器强烈推荐虽然里面没有所谓的真题但试题内容全部覆盖了的内容是考前巩固已学知识的利器7 出版的学习用书推荐我是用它过的5 官方培训幻灯片15第三章知识点123 ’s 54)5)6)’s7)8)9)3.1 提出背景在70年代网络得到了迅速的发展和应用在当时的情况下已经变成一个非常巨大的网络但是由于各种原因许多网络的设计采用不同的硬件和软件造成一个必然结果就是不同的16网络之间互相不兼容互相不能通信为了解决这个问题国际标准化组织认识到只有制定一个网络模型才能让所有网络设计人员设计出的网络能够互相通信协同工作基于此于1984年提出参考模型即我们常讲到的七层协议国际标准化组织是一个代表了130个国家的标准化组织的集体总部设在瑞士的日内瓦的目标是制定国际技术标准以促进全球信息交换和无障碍贸易你可能认为该组织应被简称为但并不意味着是一个首字母缩略字实际上在希腊语中意味着平等通过这个词汇表达了组织对标准的贡献3.2 模型的提出意义模型的主要目的就是为不同的网络提供互相兼容互相通信在网络领域我们虽然看不见一个网络中两个节点是如何通信的亦可用一个模型对通信过程进行描述通常用来描述网络通信的模型称为开放系统互连模型通过的学习您知道模型的七层结构以及各层之间如何相互作用每层具有的功能当然学习模型不足以成为一个网络专家但是熟悉模型是你17成为网络专家的必要条件3.3 模型在20世纪80年代早期即开始致力于制定一套普遍适用的规范集合以使得全球范围的计算机平台可进行开放式通信创建了一个有助于开发和理解计算机的通信模型即开放系统互连模型模型将网络结构划分为七层即物理层数据链路层网络层传输层会话层表示层和应用层每一层均有自己的一套功能集并与紧邻的上层和下层交互作用在顶层应用层与用户使用的软件如字处理程序或电子表格程序进行交互在模型的底端是携带信号的网络电缆和连接器总的说来在顶端与底端之间的每一层均能确保数据以一种可读无错排序正确的格式被发送注意组成网络部件的组合方式常被描述成它的体系结构体系结构这个词在网络领域反映了这样一个事实就像一幢建筑物包括了许多不同的但被集成在一起的部件电缆服务器协议客户机应用程序网络接口卡等等模型是对发生在网络中两节点之间过程的理论化描述它并不规定支持每一层的硬件或软件的模型但你学习到的有关网络的每件事均能对应于模型中的一层因此不仅应了解各层的名字而且应了解它们的功能及层之间相互作用的方法18图3- 1 描绘了模型层结构应用层()表示层()会话层()传输层()网络层()数据链路层( )物理层()图3 1 模型层结构3.3.1 物理层物理层是模型的最低层或第一层该层定义网络连接机械电气性能定义了包括物理连网媒介如电缆连线连接器在物理层上传输的是0 或1 比特流工作在这一层的典型网络设备为集线器术语第一层协议和物理层协议均是指描述电信号如何被放大及通过电线传输的标准区别以下两个概念*,; ,.19*..连接在上所有计算机处于一个中在中采用()技术避免的发生具体见2-20页3.3.2 数据链路层数据链路层是模型的第二层控制网络层与物理层之间的通信此层数据叫作帧数据链路层的主要功能是将从网络层接收到的数据分割成特定的可被物理层传输的帧,见图3 - 2 示出了802.3的数据帧图(6B)(6B)(6B) (2B) (46-1500B)(4B)图3-2 802.3 帧结构工作在此层的网络设备有如网桥或交换机由于它们要对帧解码并使用帧将数据发送到正确的接收方所以它们工作在数据链路层的以太网()是应用数据链路层技术的一个实例20在层常会提到即地址地址固化在网卡的中所以以简称常见的写法为00-50-04243 地址分为两大部分前24字节为厂商号加上后24字节的厂商自己分配号目的就是为了保证在全世界不会出现同样地址的网卡3.3.3 网络层网络层即模型的第三层关系到子网的运行控制主要功能是将网络地址翻译成对应的物理地址并决定如何将数据从发送方路由到接收方例如一个计算机有一个地址10.34.99.12 和一个物理地址00-60-97-3973 这种编址方案就好像说某某人的姓名和他的身份证号码相对应一样即使还有其他许多人也叫某某但他们的身份证号码是唯一的我们经常提到的地址也称作就定义在网络层地址32字节长分为网络号部分和主机号两部分常见地址的写法为16.100.1.86 对地址的详细讨论见8在网络层要区别与两个概念所谓的是指路由协议如21而是指或协议网络层通过综合考虑发送优先权网络拥塞程度服务质量以及可选路由的花费来决定从一个网络中节点到另一个网络中节点的最佳路径由于网络层处理路由而路由器因为即连接网络各段并智能指导数据传送属于网络层在网络中路由是基于编址方案使用模式以及可达性来指引数据的发送网络层协议还能补偿数据发送传输以及接收的设备能力的不平衡性为完成这一任务网络层对数据包进行分段和重组分段即是指当数据从一个能处理较大数据单元的网络段传送到仅能处理较小数据单元的网络段时网络层减小数据单元的大小的过程重组过程即是重构被分段的数据单元工作在此层的网络设备有路由器或具有第三层交换功能的交换机此层数据叫作数据包3.3.4 传输层传输层负责确保数据可靠顺序无错地从网络A点到传输到网络B点A B点可能在也可能不在相同的网络段上如果没有传输层数据将不能被接受方验证或解释所以传输层常被认为是模型中最重要的一层传输协议同时进行流量控制或是基于接22收方可接收数据的快慢程度规定适当的发送速率除此之外传输层按照网络能处理的最大尺寸将较长的数据包进行强制分割例如以太网无法接收大于1500字节的数据包发送方网络节点的传输层将数据分割成较小的数据片同时对每一数据片安排一序列号以便数据到达接收方节点的传输层时能以正确的顺序重组该过程即被称为排序在网络中传输层发送一个应答信号以通知发送方数据已被正确接收如果数据有错传输层将请求发送方重新发送数据同样假如数据在一给定时间段未被应答发送方的传输层也将认为发生了数据丢失从而重新发送它们工作在传输层的一种服务是协议族中的(传输控制协议) 另一项传输层服务是协议集的在传输层引入两个重要概念面向连接服务和无连接服务即和是在通信前先建立, 这样保证了数据传输的而是不建立连接就传输所以有更少的但不能保证数据的所以我们传要用而网上听歌因为速度更重要丢几个没关系可以用的在常见的里面是,23是对于协议要经过三次握手才能建立连接再进行数据传输三次握手具体过程见图3-4图3-4 的三次握手过程3.3.5 会话层会话层负责在网络中的两节点之间建立和维持通信术语会话指在两个实体之间建立数据交换的连接常用于表示终端与主机之间的通信会话层的功能包括建立通信链接保持会话过程A B,24通信链接的畅通同步两个节点之间的对话决定通信是否被中断以及通信中断时决定从何处重新发送当通过拨号向你的请求连接到因特网时服务器上的会话层向你与你的客户机上的会话层进行协商连接若你的电话线偶然从墙上插孔脱落时你机上的会话层将检测到连接中断并重新发起连接会话层通过决定节点通信的优先级和通信时间的长短来设置通信期限3.3.6 表示层表示层如同应用程序和网络之间的翻译官在表示层数据将按照网络能理解的方案进行编码这种编码也因所使用网络的类型不同而不同表示层协议还对图片和文件格式信息进行解码和编码3.3.7 应用层模型的第七层是应用层应用层负责对软件提供接口以使程序能使用网络服务术语应用层并不是指运行在网络上的某个特别应用程序如应用层提供的服务包括文件传输文件管理以及电子邮件的信息处理程序可以独立运行而不管发送数据时目标节点是否被连接到网络上在宽带网设计中经常会遇到第七层交换机就工作在这一层它主要起到应用25程序负载均衡作用3.4 数据封装在模型中的每一层都使用它自己的协议和接收设备的对等层通信每一层通过协议数据单元交换数据包括控制信息和数据两部分在模型中将控制信息和数据绑定的过程称作封装当某一层收到上一层之后它便进行封装过程将收到的当作本层的数据部分再加上本层的控制头信息和控制尾信息形成本层的交给下一层处理如图3-5所示N发送进程接收进程010111000101010101010126图3-5 数据封装过程概括来讲数据封装的五步为1 . ( )2 ( )3 (4 ()5 . ( )3.5 模型为了简化网络设计和管理公司提出一个三层模型来描述网络这三层为2 6到2 9快速交换层高档交换机策略层2 8页路由器终端用户接入点或3.6 产品选择具体见从2-40到2-46页公司为了简化产品选择工作27编制一个软件可以到网上第四章a的第三章第四章第五章节主要讲解设备交换机和路由器以及的一些基本知识突出实践经验知识点分布得比较散乱希望大家仔细看书4.1 路由器路由器或分为固定配置和模块化两大类路由器是考试中最重要的概念路由器有多个连接多个不同的路由器通过来决定往哪边传永远不可能往两个上传万一遇到这种情况会把掉可以人工加也可以使用如或动态维护路由器工作在283 44.1.1 路由器硬件构成路由器有六大部分组成分别为1 ――主要运行和2 ――含有用于路由器的启动和维护3 ――含有相当于机的硬盘4)―― 非易失性用于储存配置文件如文件和5 ――控制路由器启动过程具体见5-226)――主要有: 本地配置端口要用( 的原装是蓝色的)一头连在上另一头连在机的口上然后用登录进行配置一般情况下路由器都是用进行配置的这种情况也叫带内配置0代表第一个: 辅助的意思就是用连接进行远程调试路由器用处不是很大在某些路由器里面都没29有这以太口或快速以太口用于连接局域网e0 代表第一个如果是第一个的话用0 来表示分为固定配置和模块化配置两种情况在模块化配置情况下还需要购买卡如( )一般用s0代表第一个用于连接路由器的接口命名规则是按从右往左从下往上的顺序排列的比如有两个左边那个就是e1 右边那个就是e0 如果这两个是上下排列的下面那个就是e0 上面那个就是e1 在有的里面一个里面会有多个这时候你可以用e1/0 e1/1 e1/2 等符号来表示4.2 ( )正如的叫的叫其实里面的都很便宜的大多数也就是486 的水平现在的也就卖几百美金为什么这个小小的就敢卖好几千的美金就应该是这个30如果说是靠垄断了市场那么说是靠来垄断了市场真是一点都不为过4.2.1 界面是( ) 的象里面的都是的而是() 的特点是比较难学但配置起来比较快现在也正在做的,但大家还是喜欢的件进行练习有两种方式和在学习命令的时候一定要记住所使用的命令处于何种提示符下在中经常会遇到以下提示符如下表提示符描述>()# 全局配置模式()# 端口配置模式()# 子端口配置模式()# 配置模式如异步拨入() # 动态路由协议配置如4.2.2 常用命令在中我们要掌握和熟记一些常用命令见下表31命令描述查看版本号显示当前在内存中运行的配置信息显示保存于中的配置信息显示内容如名称大小查看端口状态16.100.1.5 255.255.255.0 在端口上配置地址进入菜单配置模式进入全局配置模式修改路由器或交换机名称() 0()()配置进入口口令() 0 4()()配置进入口令() 进入口令() 代替口令640000 在端口设置通信速率为64K64 在命令中会表现出来它设定路由协议所能使用的带宽而非通信线路上的实际带宽() 使能一个端口0 查看某个端口的电缆类型为或为查看建立会话个数查看口是否在使用并列出所有会话有关之间的转换关系见的5-27页10.5.5.3 设定网关地址帮助命令> -> -> ->32注意在上配置只是为了利于远程管理4.2.3 外部配置方式外部配置方式有12)3)4)5)4.2.4 常用快捷键- a- a- a--( ) -( ) -( ) -( ) ---- .- a4.2.5是特有的用于收集直接相邻设备信息的管理工具工作在模型的33层采用帧结构默认情况下是的每60秒发送一次广播它的是180秒涉及的有一些命令有() ――启动() ――关闭() 30――设置广播时间() 120――设置保留时间――查看直接相邻设备五大类信息如4.2.6用于控制路由器启动过程其工作原理类似机中的在默认情况下它的值为0x2102 可以用命令来查看长为16 其中低4叫作设置不同的值可以让路由器启动到不同的工作状态具体为0x0(0000) 启动到状态提示符为或>0x1(0001) 从启动提示符为()0x2(0010)-0(1111) 正常启动到中查找命令34及其含义含义0x2102 缺省设置13=0x2000 引导失败5次后自动从引导8=0x0100 关闭键0x2 从中引导正常运行模式0x210113=0x2000 引导失败5次后自动从引导8=0x0100 关闭键0x1 进入运行模式()>0x1428=0x0040 进入运行模式>0x2 从中引导正常运行模式4.2.7 口令恢复。

CCNA 2 - Chapter 11What is one advantage of using the cut-through switching method instead of the store-and-forward switching method?has a positive impact on bandwidth by dropping most of the invalid framesmakes a fast forwarding decision based on the source MAC address of the framehas a lower latency appropriate for high-performance computing applications*provides the flexibility to support any mix of Ethernet speeds2A network designer must provide a rationale to a customer for a design which will move an enterprise from a flat network topology to a hierarchical network topology. Which two features of the hierarchical design make it the better choice? (Choose two.)reduced cost for equipment and user trainingless required equipment to provide the same performance levelssimpler deployment for additional switch equipment*easier to provide redundant links to ensure higher availability*lower bandwidth requirements3What are two advantages of modular switches over fixed-configuration switches? (Choose two.)availability of multiple ports for bandwidth aggregationlower forwarding ratesneed for fewer power outlets*lower cost per switchincreased scalability*4Refer to the exhibit. Consider that the main power has just been restored. PC1 asks the DHCP server for IPv4 addressing. The DHCP server sends it an IPv4 address. While PC2 is still booting up, PC3 issues a broadcast IPv4 DHCP request. To which port will SW1 forward this request?to Fa0/1, Fa0/2, and Fa0/4 onlyto Fa0/1, Fa0/2, Fa0/3, and Fa0/4to Fa0/1 and Fa0/2 onlyto Fa0/1, Fa0/2, and Fa0/3 only*to Fa0/1 only5What is one function of a Layer 2 switch?forwards data based on logical addressinglearns the port assigned to a host by examining the destination MAC addressduplicates the electrical signal of each frame to every portdetermines which interface is used to forward a frame based on the destination MAC address*6Refer to the exhibit. Fill in the blank.There are ” 12” collision domains in the topology.7What is a collapsed core in a network design?a combination of the functionality of the access, distribution, and core layersa combination of the functionality of the access and core layersa combination of the functionality of the distribution and core layers*a combination of the functionality of the access and distribution layers 8What are two reasons a network administrator would segment a network with a Layer 2 switch? (Choose two.)to enhance user bandwidth*to eliminate virtual circuitsto create more broadcast domainsto isolate traffic between segments*to isolate ARP request messages from the rest of the networkto create fewer collision domains9Refer to the exhibit.How is a frame sent from PCA forwarded to PCC if the MAC address table on switch SW1 is empty?SW1 forwards the frame directly to SW2. SW2 floods the frame to all ports connected to SW2, excluding the port through which the frame entered the switch.SW1 floods the frame on all ports on the switch, excluding the interconnected port to switch SW2 and the port through which the frame entered the switch.SW1 floods the frame on all ports on SW1, excluding the port through which the frame entered the switch.*SW1 drops the frame because it does not know the destination MAC address.10Place the options in the following order:[+] appropriate for high performance computing applications[+] forwarding process can begin after receiving the destination address [+] may forward invalid frames[#] error checking before forwarding[#] forwarding process only begin after receiving the entire frame [#] only forward valid frames[+] Order does not matter within this group.[#] Order does not matter within this group.11What is a basic function of the Cisco Borderless Architecture distribution layer?aggregating Layer 3 routing boundaries*aggregating all the campus blocksacting as a backboneproviding access to the user12ABC, Inc. has about fifty hosts in one LAN. The administrator would like to increase the throughput of that LAN. Which device will increase the number of collision domains and thereby increase the throughput of the LAN?hubhostNICswitch*13What does the term “port density” represent for an Ethernet switch?the numbers of hosts that are connected to each switch portthe speed of each portthe memory space that is allocated to each switch portthe number of available ports*14Which type of transmission does a switch use when the destination MAC address is not contained in the MAC address table?anycastunicastbroadcast*multicast15What is a basic function of the Cisco Borderless Architecture access layer?aggregates Layer 3 routing boundariesprovides high availabilityaggregates Layer 2 broadcast domainsprovides access to the user*16What information is added to the switch table from incoming frames?source MAC address and incoming port number*destination MAC address and incoming port numberdestination IP address and incoming port numbersource IP address and incoming port number17Fill in the blank.A “converged” network is one that uses the same infrastructure to carry voice, data, and video signals.18An administrator purchases new Cisco switches that have a feature called StackPower. What is the purpose of this feature?It enables many switches to be connected with a special fiber-optic power cable to provide higher bandwidth.It enables the sharing of power among multiple stackable switches.*It enables many switches to be connected to increase port density.It enables many switches to be physically stacked in an equipment rack.It enables AC power for a switch to be provided from a powered patch panel.19Which switch form factor should be used when large port density, fault tolerance, and low price are important factors?fixed-configuration switchmodular switchstackable switch*rackable 1U switch20Refer to the exhibit. Fill in the blank.There are ” 5 ”CCNA 2 - Chapter 2Posted by beotron at 8:59 PM1. A static route that points to the next hop IP will have what administrative distance and metric in the routing table?• administrative distance of 0 and metric of 0• administrative distance of 0 and metric of 1• administrative distance of 1 and metric of 0• administrative distance of 1 and metric of 12. What address can be used to summarize networks 172.16.1.0/24, 172.16.2.0/24, 172.16.3.0/24, and 172.16.4.0/24?• 172.16.0.0/21• 172.16.1.0/22• 172.16.0.0 255.255.255.248• 172.16.0.0 255.255.252.03. The routers in the diagram use the subnet assignments shown. What is the most efficient route summary that can be configured on Router3 to advertise the internal networks to the cloud?• 192.1.1.0/26 and 192.1.1.64/27• 192.1.1.128/25• 192.1.1.0/23 and 192.1.1.64/23• 192.1.1.0/24• 192.1.1.0/25• 192.1.1.0/24 and 192.1.1.64/244. Refer to the exhibit. What is the significance of the /8 in the route to the 10.0.0.0 network?• It indicates that there are 8 hops between this router and the 10.0.0.0 network.• It represents the time, in milliseconds, it takes for a ping to reply when sent to the 10.0.0.0 network.• It indicates that there are 8 subnets in the destination network to which the router can forward packets.• It indicates the number of consecutive bits, from the left, in the destination IP address of a packet that must match 10.0.0.0 to use that route.5. Refer to the exhibit. How will packets destined to the 172.16.0.0 network be forwarded?• Router1 will perform recursive lookup and packet will exit S0/0.• Router1 will perform recursive lookup and packet will exit S0/1.• There is no matching interface associated with network 172.16.0.0 so packets will be dropped.• There is no matching interface associated with network 172.16.0.0 so packets will take gateway of last resort and exit out S0/2.6. A network administrator enters the following command into Router1: ip route 192.168.0.0255.255.255.0 S0/1/0. Router1 then receives a packet that is destined for 192.168.0.22/24. After finding the recently configured static route in the routing table, what does Router1 do next to process the packet? • drops the packet because the destination host is not listed in the routing table• looks up the MAC address of the S0/1/0 interface to determine the destination MAC address of the new frame• performs a recursive lookup for the IP address of the S0/1/0 interface before forwarding the packet• encapsulates the packet into a frame for the WAN link and forwards the packet out the S0/1/0 interface7. Refer to the exhibit. Given the output in the exhibit, how would a clock rate be determined for this link? • The rate would be negotiated by both routers.• A rate would not be selected due to the DCE/DTE connection mismatch.• The rate configured on the DTE determines the clock rate.• The rate configured on the DCE determines the clock rate.8. Refer to the exhibit. Which set of commands will configure static routes that will allow the WinterPark and the Altamonte routers to deliver packets from each LAN and direct all other traffic to the Internet? • WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 0.0.0.0 0.0.0.0 s0/1• WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 198.18.222.0 255.255.255.255 s0/1• WinterPark(config)# ip route 172.191.67.0 255.255.255.0 192.168.146.1• WinterPark(config)# ip route 0.0.0.0 0.0.0.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2• WinterPark(config)# ip route 172.191.67.0 255.255.255.0 192.168.146.1Altamonte(config)# ip route 10.0.234.0 255.255.255.0 192.168.146.2Altamonte(config)# ip route 0.0.0.0 0.0.0.0 s0/09. Hosts on two separate subnets cannot communicate. The network administrator suspects a missing route in one of the routing tables. Which three commands can be used to help troubleshoot Layer 3 connectivity issues? (Choose three.)• ping• show arp• traceroute• show ip route• show interface• show cdp neighbor d etail10. Refer to the exhibit. A company network engineer is assigned to establish connectivity between the two Ethernet networks so that hosts on the 10.1.1.0/24 subnet can contact hosts on the 10.1.2.0/24 subnet. The engineer has been told to use only static routing for these company routers. Which set of commands will establish connectivity between the two Ethernet networks?• R1(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1R2(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2• R1(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.1• R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.2R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.1• R1(config)# ip route 10.1.1.0 255.255.255.0 192.168.0.1R2(config)# ip route 10.1.2.0 255.255.255.0 192.168.0.2• R1(config)# ip route 0.0.0.0 0.0.0.0 10.1.2.1R2(config)# ip route 0.0.0.0 0.0.0.0 10.1.1.111. Which of the following are displayed by the Router# show cdp neighbors command? (Choose three.) • load• platform• reliability• holdtime• local interface12. Refer to the exhibit. What two commands are required to provide connectivity between the192.168.1.0 and 10.0.0.0 networks without requiring recursive lookup? (Choose two.)• A(config)# ip route 10.0.0.0 255.0.0.0 s 0/1/0• A(config)# ip route 10.0.0.0 255.0.0.0 172.16.40.2• A (config)# ip route 10.0.0.0 255.0.0.0 s 0/0/0• B(config)# ip route 192.168.1.0 255.255.255.0 s 0/0/0• B (config)# ip route 192.168.1.0 255.255.255.0 172.16.40.1• B(config)# ip route 192.168.1.0 255.255.255.0 s 0/1/013. Refer to the exhibit. What two commands will change the next-hop address for the 10.0.0.0/8 network from 172.16.40.2 to 192.168.1.2? (Choose two.)• A(config)# no network 10.0.0.0 255.0.0.0 172.16.40.2• A(config)# no ip address 10.0.0.1 255.0.0.0 172.16.40.2• A(config)# no ip route 10.0.0.0 255.0.0.0 172.16.40.2• A(config)# ip route 10.0.0.0 255.0.0.0 s0/0/0• A(config)# ip route 10.0.0.0 255.0.0.0 192.168.1.214. What happens to a static route entry in a routing table when the outgoing interface is not available? • The route is removed from the table.• The router polls neighbors for a replacement route.• The route remains in the table because it was defined as static.• The router redirects the static route to compensate for the loss of the next hop device.15. A router has one static route to each destination network. Which two scenarios would require an administrator to alter the static routes that are configured on that router? (Choose two.)• The destination network no longer exists.• The destination network is moved to a different interface on the same router.• The path between the source and destination is upgraded with a higher bandwidth link.• A topology change occurs where the exi sting next-hop address or exit interface is not accessible.• The remote destination network interface has to be down for 15 minutes of maintenance.16. Why is it advisable to enter a next-hop IP address when creating a static route whose exit interface is an Ethernet network?• Adding the next-hop address eliminates the need for the router to do any lookups in the routing table before forwarding a packet.• In a multi-access network, the router cannot determine the next-hop MAC address for the Ethernet frame without a next-hop address.• Using a next-hop address in a static route provides a route with a lower metric.• In multi-access networks, using a next-hop address in a static route makes that route a candidate default route.17. The output of the Router# show interfaces serial 0/1 command displays the following:• Serial0/1 is up, line protocol is down.• What is the most likely cause for the line protocol being down?• Serial0/1 is shutdown.• There is no cable connecting the routers.• The remote rout er is using serial 0/0.• No clock rate has been set.18. Refer to the exhibit. Which static route should be configured on Router1 so that host A will be able to reach host B on the 172.16.0.0 network?• ip route 192.168.0.0 172.16.0.0 255.255.0.0• ip rou te 172.16.0.0 255.255.0.0 192.168.0.1• ip route 172.16.0.0 255.255.0.0 S0/0/1• ip route 172.16.0.0 255.255.0.0 S0/0/019. What two devices are responsible for converting the data from the WAN service provider into a form acceptable by the router? (Choose two).• the serial port of the router• a modem• a switch• the ethernet port of the router• a CSU/DSU device• a DTE device20. Which of the following is true regarding CDP and the graphic shown?• CDP running on Router D will gather information about routers A, B, C, and E.• By default, Router A will receive CDP advertisements from routers B and C.• If routers D and E are running different routing protocols, they will not exchange CDP information.• Router E can use CDP to identify the IOS running on Router B.21. Which two statements describe functions or characteristics of CDP? (Choose two.)• It starts up automatically and allows the device to detect directly connected neighbor devices that use CDP.• It operates at the network layer and allows two systems to learn about each other.• It creates a topology map of the entire network.• It allows systems to learn about each other even if different network layer protocols are configured.• It forwards advertisements about routes for faster convergence.22. Which piece of information is available from examining the output of the command show ip interface brief?• Interface speed and duplex• Interface MTU• Errors• Interface MAC address• Interface IP addressCCNA 2 - Chapter 31A network administrator is determining the best placement of VLAN trunklinks. Which two types of point-to-point connections utilize VLAN trunking? (Choose two.)between two switches that share a common VLANbetween a switch and a server that has an 802.1Q NIC*between a switch and a client PCbetween a switch and a network printerbetween two switches that utilize multiple VLANs*2What happens to a port that is associated with VLAN 10 when the administrator deletes VLAN 10 from the switch?The port automatically associates itself with the native VLAN. The port creates the VLAN again.The port goes back to the default VLAN.The port becomes inactive.*3Refer to the exhibit. Interface Fa0/1 is connected to a PC. Fa0/2 is a trunk link to another switch. All other ports are unused. Which security best practice did the administrator forget to configure?Configure all unused ports to a ‘black-hole’ VLAN that is not used f or anything on the network.Disable autonegotiation and set ports to either static access or static trunk.Change the native VLAN to a fixed VLAN that is distinct from all user VLANs and to a VLAN number that is not VLAN 1.All user ports are associated with VLANs distinct from VLAN 1 and distinct from the ‘black-hole’ VLAN.*4Which command is used to remove only VLAN 20 from a switch?no switchport access vlan 20delete flash:vlan.datno vlan 20*delete vlan.dat5A Cisco Catalyst switch has been added to support the use of multiple VLANs as part of an enterprise network. The network technician finds it necessary to clear all VLAN information from the switch in order to incorporate a new network design. What should the technician do to accomplish this task?Erase the startup configuration and reboot the switch.Erase the running configuration and reboot the switch.Delete the startup configuration and the vlan.dat file in the flash memory of the switch and reboot the switch.*Delete the IP address that is assigned to the management VLAN and reboot the switch.6What is the effect of issuing a switchport access vlan 20 command on the Fa0/18 port of a switch that does not have this VLAN in the VLAN database?VLAN 20 will be created automatically.*The command will have no effect on the switch.Port Fa0/18 will be shut down.An error stating that VLAN 20 does not exist will be displayed and VLAN 20 is not created.Which command displays the encapsulation type, the voice VLAN ID, and the access mode VLAN for the Fa0/1 interface?show mac address-table interface Fa0/1show interfaces Fa0/1 switchport*show interfaces trunkshow vlan brief8Place the options in the following order:- not scored -dynamic autononegotiatedynamic desirabletrunk9Port Fa0/11 on a switch is assigned to VLAN 30. If the command no switchport access vlan 30 is entered on the Fa0/11 interface, what will happen?Port Fa0/11 will be returned to VLAN 1.*VLAN 30 will be deleted.An error message would be displayed.Port Fa0/11 will be shutdown.What must the network administrator do to remove Fast Ethernet port fa0/1 from VLAN 2 and assign it to VLAN 3?Enter the no vlan 2 and the vlan 3 commands in global configuration mode. Enter the switchport trunk native vlan 3 command in interface configuration mode.Enter the switchport access vlan 3 command in interface configuration mode.*Enter the no shutdown in interface configuration mode to return it to the default configuration and then configure the port for VLAN 3.11Which two Layer 2 security best practices would help prevent VLAN hopping attacks? (Choose two.)Disable DTP autonegotiation on end-user ports.*Change the management VLAN to a distinct VLAN that is not accessible by regular users.Statically configure all ports that connect to end-user host devices to be in trunk mode.Change the native VLAN number to one that is distinct from all user VLANs and is not VLAN 1.*Use SSH for all remote management access.12In a basic VLAN hopping attack, which switch feature do attackers take advantage of?automatic encapsulation negotiationthe default automatic trunking configuration*an open Telnet connectionforwarding of broadcasts13A Cisco switch currently allows traffic tagged with VLANs 10 and 20 across trunk port Fa0/5. What is the effect of issuing a switchport trunk allowed vlan 30 command on Fa0/5?It allows only VLAN 30 on Fa0/5.*It allows a native VLAN of 30 to be implemented on Fa0/5.It allows VLANs 1 to 30 on Fa0/5.It allows VLANs 10, 20, and 30 on Fa0/5.14Refer to the exhibit. A frame is traveling between PC-A and PC-B through the switch. Which statement is true concerning VLAN tagging of the frame?No VLAN tag is added to the frame.*A VLAN tag is added when the frame is accepted by the switch.A VLAN tag is added when the frame is forwarded out the port to PC-B.A VLAN tag is added when the frame leaves PC-A.15Refer to the exhibit. PC-A and PC-B are both in VLAN 60. PC-A is unable to communicate with PC-B. What is the problem?The native VLAN is being pruned from the link.The VLAN that is used by PC-A is not in the list of allowed VLANs on the trunk.*The trunk has been configured with the switchport nonegotiate command. The native VLAN should be VLAN 60.16What VLANs are allowed across a trunk when the range of allowed VLANs is set to the default value?All VLANs will be allowed across the trunk.*Only the native VLAN will be allowed across the trunk.The switches will negotiate via VTP which VLANs to allow across the trunk. Only VLAN 1 will be allowed across the trunk.17Under which two occasions should an administrator disable DTP while managing a local area network? (Choose two.)on links that should not be trunking*when connecting a Cisco switch to a non-Cisco switch*on links that should dynamically attempt trunkingwhen a neighbor switch uses a DTP mode of dynamic autowhen a neighbor switch uses a DTP mode of dynamic desirable18Open the PT Activity. Perform the tasks in the activity instructions and then answer the question.Which PCs will receive the broadcast sent by PC-C?PC-D, PC-E*PC-A, PC-B, PC-D, PC-EPC-A, PC-BPC-A, PC-B, PC-D, PC-E, PC-FPC-A, PC-B, PC-E19Which two statements are true about VLAN implementation? (Choose two.)The network load increases significantly because of added trunking information.Devices in one VLAN do not hear the broadcasts from devices in another VLAN.*The size of the collision domain is reduced.VLANs logically group hosts, regardless of physical location.*The number of required switches in a network decreases.20Refer to the exhibit. DLS1 is connected to another switch, DLS2, via a trunk link. A host that is connected to DLS1 is not able to communicate to a host that is connected to DLS2, even though they are both in VLAN 99. Which command should be added to Fa0/1 on DLS1 to correct the problem?switchport trunk allowed vlan add 99switchport trunk native vlan 66*switchport mode dynamic autoswitchport nonegotiate21Which switch feature ensures that no unicast, multicast, or broadcast traffic is passed between ports that are configured with this feature?switch port securityPVLAN protected port*ACLVLAN22Fill in the blank. Use the full command syntax.The ” show vlan brief” command displays the VLAN assignment for all ports as well as the existing VLANs on the switch.23Which three statements accurately describe VLAN types? (Choose three).An 802.1Q trunk port, with a native VLAN assigned, supports both tagged and untagged traffic.*A management VLAN is any VLAN that is configured to access management features of the switch.*A data VLAN is used to carry VLAN management data and user-generated traffic.Voice VLANs are used to support user phone and e-mail traffic on a network. VLAN 1 is always used as the management VLAN.After the initial boot of an unconfigured switch, all ports are members of the default VLAN.*24Which command should the network administrator implement to prevent the transfer of DTP frames between a Cisco switch and a non-Cisco switch?S1(config-if)# switchport mode trunkS1(config-if)# switchport mode accessS1(config-if)# switchport nonegotiate*S1(config-if)# switchport mode dynamic desirableS1(config-if)# switchport trunk allowed vlan noneCCNA 2 - Chapter 41What type of IPv6 address is required as a minimum on IPv6 enabled interfaces?staticglobal unicastlink-local*loopbackunique local2In order for packets to be sent to a remote destination, what three pieces of information must be configured on a host? (Choose three.)default gateway*hostnameDNS server addressDHCP server addressIP address*subnet mask*3What two pieces of information are displayed in the output of the show ip interface brief command? (Choose two.)MAC addressesLayer 1 statuses*IP addresses*next-hop addressesinterface descriptionsspeed and duplex settings4Place the options in the following order:next hopdestination networkmetric- not scored -administrative distanceroute timestamproute source protocol- not scored -5Which two items are used by a host device when performing an ANDing operation to determine if a destination address is on the same local network? (Choose two.)destination MAC addressnetwork numberdestination IP address*source MAC addresssubnet mask*6Refer to the exhibit. A network administrator issues the show ipv6 route command on R1. What two conclusions can be drawn from the routing table? (Choose two.)Packets that are destined for the network 2001:DB8:ACAD:2::/64 will be forwarded through Fa0/1.R1 does not know a route to any remote networks.*The interface Fa0/1 is configured with IPv6 address2001:DB8:ACAD:A::12.*Packets that are destined for the network 2001:DB8:ACAD:2::54/128 will be forwarded through Fa0/0.The network FF00::/8 is installed through a static route command.7Refer to the exhibit. What is the purpose of the highlighted field in the line that is displayed from the show ip route command?It indicates that this is a directly connected route.It indicates that this route has been deleted from the routing table. It indicates that this route was learned via EIGRP.*It indicates that this is a default route.8Which two statements correctly describe the concepts of administrative distance and metric? (Choose two.)The metric varies depending which Layer 3 protocol is being routed, such as IP.A router first installs routes with higher administrative distances. The value of the administrative distance can not be altered by the network administrator.Routes with the smallest metric to a destination indicate the best path.* Administrative distance refers to the trustworthiness of a particular route.*The metric is always determined based on hop count.9What are two functions of a router? (Choose two.)It manages the VLAN database.It increases the size of the broadcast domain.It controls the flow of data via the use of Layer 2 addresses.It determines the best path to send packets.*It connects multiple IP networks.*10A packet moves from a host on one network to a device on a remote network within the same company. If NAT is not performed on the packet, which two items remain unchanged during the transfer of the packet from source to destination? (Choose two.)destination MAC addresssource ARP tablesource IP address*destination IP address*source MAC addressLayer 2 header11。

完整版CCNA测试题库及答案描述载波侦听多路由访问/冲突检测（CSMA/CD）的工作原理。

CSMA/CD是一种帮助设备均衡共享带宽的协议，可避免两台设备同时在网络介质上传输数据。

虽然他不能消除冲突，但有助于极大的减少冲突，进而避免重传，从而提高所的设备的数据传输效率。

区分半双工和全双工通信。

并指出两种方法的需求。

与半双工以太网使用一对导线不同，全双工以太网使用两队导线，全双工使用不同的导线来消除冲突，从而允许同时发送和接收数据，而半双工可接收或发送数据，但不能同时接收和发送数据，且仍会出现冲突。

要使用全双工，电缆两端的设备都必须支持全双工，并配置成一全双模式运行。

描述MAC地址的组成部分以及各部分包含的信息。

MAC（硬件）地址时一种使用十六进制表示的地址，长48位（6B）。

其中前24位（3B）称为OUI（Organizationally Unique Idebtifier,组织唯一表示符），有IEEE分配给NIC制造商；余下的部分呢唯一地标识了NIC识别十进制数对应的二进制值和十六进制值。

用这三种格式之一表示的任何数字都可以转换为其他两种格式，能够执行这种转换对理解IP地址和子网划分至关重要。

识别以太网帧中与数据链路层相关的字段。

在以太网中，与数据链路层相关的字段包括前导码，帧其实位置分隔符，目标MAC地址，源MAC地址，长度或者类型以及帧校验序列。

识别以太网布线相关的IEEE标准。

这些标准描述了各种电缆类型的功能和物理特征，包括（但不限于）10Base2、10Base5和10BaseT。

区分以太网电缆类型及其用途。

以太网电缆分3种：直通电缆，用于将PC或路由器的以太网接口连接到集线器或交换机；交叉电缆。

用于将集线器连接到集线器，集线器连接到交换机，交换机连接到交换机以及PC连接到PC；反转电缆，用于PC和路由器或交换机之间建立控制台连接。

描述数据封装过程及其在分组创建中的作用。

数据封装指的是在OSI模型各层给数据添加信息的过程，也成为分组创建。

C C N A第章考试答案 IMB standardization office【IMB 5AB- IMBK 08- IMB 2C】••试题反馈报告IntroductiontoNetworks(版本-ITN第1章考试以下是针对您未获得满分的试题给出的反馈。

某些交互式试题可能不显示您的答案。

1 某公司正在考虑是使用客户端/服务器还是对等网络。

下列哪三项是对等网络的特征（选择三项。

）正确响应您的响应易于创建同时充当客户端和服务器时设备性能更好可扩展安全性提升缺少集中管理实施成本更少由于不需要使用网络设备和专用服务器，对等网络易于创建，复杂性更低，且成本更少。

而且对等网络也没有集中管理。

这种网络安全性更低，不可扩展，而且那些同时充当客户端和服务器的设备可能性能更差。

此试题参考以下领域的内容：IntroductiontoNetworks•提供网络资源2 哪种设备的功能是确定消息在网际网络中传输的路径？正确响应您的响应路由器防火墙Web服务器DSL调制解调器路由器用于确定消息在网络中的传输路径。

防火墙用于过滤传入和传出的流量。

DSL调制解调器用于为家庭或组织提供Internet连接。

此试题参考以下领域的内容：IntroductiontoNetworks•网络组件3 哪两个条件有助于您从各种网络介质当中选择一种网络介质（请选择两项。

）正确响应您的响应网络上使用的终端设备的成本所选介质可以成功传送信号的距离需要优先处理的数据类型安装在网络中的中间设备的数量要安装所选介质的环境选择网络介质的条件包括：所选介质可以成功传送信号的距离、要安装所选介质的环境、必须传输的数据量和速度以及介质和安装的成本。

此试题参考以下领域的内容：IntroductiontoNetworks•网络组件4 下列哪两项描述了中间设备（选择两项。

）正确响应您的响应中间设备可以引导数据路径。

中间设备可以生成数据内容。

中间设备可以启动封装过程。

中间设备可以更改数据内容。

CCNA认证基础-习题分析讲义第一部分第一章1. Convert the binary number 10111010 into its hexadecimal equivalent. Select thecorrect answer from the list below. （3）1) 852) 903) BA4) A15) B36) 1C2. Convert the Hexadecimal number A2 into its Base 10 equivalent. Select thecorrect answer from the list below. （4）1) 1562) 1583) 1604) 1625) 1646) 1663. Which binary number is a representation of the decimal number 248? （3）1) 111010002) 111101003) 111110004) 111110104. Which of the following will test the internal loopback of a node? （3）1) ping 10.10.10.12) ping 192.168.1.13) ping 127.0.0.14) ping 223.223.223.2235) ping 255.255.255.2555. What can be verified by successfully pinging the reserved loopback address ona host? （2）1) Connectivity exists between two hosts on the LAN.2) The TCP/IP stack of the local host is configured correctly.3) A connection exists between a host and the default gateway.4) The route a packet takes from the local host to a remote host is valid.6. Which of the following commands could be used on a Windows-basedcomputer to view the current IP configuration of the system? (Choose two.) （3，4）1) configip2) ifconfig3) ipconfig4) winipcfg5) Winipconfig7.Refer to the exhibit. What must be configured on Host B to allow it to communicate withthe Host C? (Choose three.) （2，4，6）1)the MAC address of RTA router interface connected to Switch 12) a unique host IP address3)the IP address of Switch 14)the default gateway address5)the MAC address of Host C6)the subnet mask for the LAN8. What are important characteristics to consider when purchasing a networkinterface card? (Choose two.) （2，3）1) security used on the network2) media used on the network3) system bus used on the computer4) software installed on the network5) diagnostic tools installed on the network第二章1. Select the necessary information that is required to compute the estimated timeit would take to transfer data from one location to another. (Choose two.) （1，5）1) file size2) data format3) network in use4) type of medium5) bandwidth of the link2. Using the data transfer calculation T=S/BW, how long would it take a 4MB file tobe sent over a 1.5Mbps connection? （2）1) 52.2 seconds2) 21.3 seconds3) 6.4 seconds4) 2 seconds5) 0.075 seconds6) 0.0375 seconds3. What are features of the TCP/IP Transport layer? (Choose two.) （3，5）1) path determination2) handles representation, encoding and dialog control3) uses TCP and UDP protocols4) packet switching5) reliability, flow control and error correction4. Which of the following is the Layer 4 PDU? （4）1) bit2) frame3) packet4) Segment5. What is important to remember about the data link layer of the OSI model whenconsidering Peer to Peer communication? (Choose three.) （3，4，5）1) It links data to the transport layer.2) It encapsulates frames into packets.3) It provides a service to the network layer.4) It encapsulates the network layer information into a frame.5) Its header contains a physical address which is required to complete the datalink functions.6) It encodes the data link frame into a pattern of 1s and 0s (bits) for transmissionon the medium.6. Which statement describes a star topology? （2）1) Each host in the network is connected to a backbone cable that is terminated atboth ends.2) Each host is connected to a hub or switch, either of which acts as a central pointfor all network connections.3) Each host is directly connected to two other hosts to form a long chain of hosts.4) Each host has a connection to all other hosts in the network.7. Which statements describe the logical token-passing topology? (Choose two.)（2）1) Network usage is on a first come, first serve basis.2) Computers are allowed to transmit data only when they possess a token.3) Data from a host is received by all other hosts. Electronic tokens are passedsequentially to each other.4) Token passing networks have problems with high collision rates.8. Which technologies are considered to be LAN technologies? (Choose two.) （2，5）1) DSL2) Token Ring3) Frame Relay4) ISDN5) Ethernet9.Refer to the exhibit. Host A wants to send a message to host B. Place the following stepsin the correct order so that the message can be sent. （4）A - add network layer addressesB - transmit bitsC - create application dataD - add data link layer addresses1) B, A, D, C2) D, A, C, B3) A, D, A, B4) C, A, D, B5) C, D, A, B6) C, B, A, D10.After an uns u ccessful ping to the local router, the technician decides to investigate therouter. The technician observes that the lights and fan on the router are not operational.In which layer of the OSI model is the problem most likely occurring? （4）1) transport2) network3) data link4) physical11. Refer t o the exhibit. What is the order of the TCP/IP Protocol Data Units as datais moved as indicated through the OSI model? （3）1) data, segments, frames, packets, bits2) data, packets, segments, frames, bits3) data, segments, packets, frames, bits4) data, packets, frames, segments, bits第三章1. Which combinations of charges will be repelled by electric force? (Choose two.)（4，6）1) neutral and neutral2) neutral and positive3) neutral and negative4) positive and positive5) positive and negative6) negative and negative2. Which of the following are considered the best media for use in data networkcommunications? (Choose three.) （2，3，6）1) glass2) fibers3) copper4) gold5) plastic6) silicon7) Silver3. Which of the following wireless standards increased transmission capabilitiesto 11 Mbps? （2）1) 802.11a2) 802.11b3) 802.11c4) 802.11d4. What is attenuation? （3）1) opposition to the flow of current2) measurement of electrical signals relative to time3) degradation of a signal as it travels along the medium4) amount or volume of traffic that is flowing on the medium5. Which cable specifications are indicated by 10BASE-T? （3）1) 10 Mbps transmission speed, baseband signal, 500 meter cable length, coaxialcable2) 10 Mbps transmission speed, broadband signal, 100 meter cable length, coaxialcable3) 10 Mbps transmission speed, baseband signal, 100 meter cable length,twisted-pair cable4) 10 Gbps transmission speed, broadband signal, 500 meter cable length,twisted-pair cable6. For which Ethernet installations would fiber optic rather than Cat5 UTP be abetter media choice? (Choose two.) （2，4）1) a 3 meter connection between two 10BASE-T hubs2) an environment with many potential sources of EMI and RFI3) a peer to peer connection between two NICs with RJ45 connectors4) an installation between two buildings that are located 500 meters apart5) a single building installation where installation costs are the major concern7. Refer to the exhibit. Which type of UTP cable should be used to connect Host Ato Switch1? （4）1) rollover2) console3) crossover4) straight-through8. Refer to the exhibit. Which type of Category 5 cable is used to make an Ethernetconnection between Host A and Host B? （3）1) coax cable2) rollover cable3) crossover cable4) straight-through cable第四章1. During cable testing, which of the following are used to calculate theinformation carrying capacity of a data cable? (Choose two.) （2，5）1) bit speed2) attenuation3) wire map4) saturation limit5) analog bandwidth2. What type of wiring problem is depicted in this sample of a cable tester? （3）1) a fault2) a short3) an open4) a split a good map3. In a new network installation, the network administrator has decided to use amedium that is not affected by electrical noise. Which cable type will best meet this standard? （5）1) coaxial2) screened twisted pair3) shielded twisted pair4) unshielded twisted pair5) fiber optic4. How does network cable length affect attenuation? （3）1) Category 5 cable that is run in metal conduit has the highest attenuation in theshortest distance.2) Shorter cable lengths have greater signal attenuation.3) Longer cable lengths have greater signal attenuation.4) The length of the cable has no effect on signal attenuation.第五章1. The highest capacity Ethernet technologies should be implemented in whichareas of a network? (Choose three.) （3，4，5）1) between workstation and backbone switch2) between individual workstations3) between backbone switches4) between enterprise server and switch5) on aggregate access links2. What device must be used between an AUI port of a networking device and themedia to which it is being connected? （3）1) a transducer2) a transmitter3) a transceiver4) a transponder5) a port replicator3. An ISDN Basic Rate Interface (BRI) is composed of how many signalingchannels? （1）1) 12) 23) 34) 44. Which layer of the OSI model covers physical media? （1）1) Layer 12) Layer 23) Layer 34) Layer 45) Layer 56) Layer 65. What type of network cable is used between a terminal and a console port? （3）1) cross-over2) straight-through3) rollover4) patch cable6. What is the recommended maximum number of workstations configured on apeer-to-peer network? （3）1) 252) 153) 104) 55) 27. Which of the following increases the potential for a collision to occur? （4）1) the use of an active hub instead of an intelligent hub2) the use of an intelligent hub instead of an active hub3) a reduction in the number of devices attached to the hub4) an increase in the number of devices attached to the hub8. What is the maximum length of a media segment used for 100BASE-TX? （1）1) 100 meters2) 185 meters3) 400 meters4) 500 meters9. Which cable diagram displays the end to end pinout for a crossover cable usedwith Cisco devices? （3）1) Cable A2) Cable B3) Cable C4) Cable D第六章1. What does the "10" in 10Base2 indicate about this version of Ethernet? （2）1) The version uses Base10 numbering within the frames.2) The version operates at a transmission rate of 10 Mbps.3) Frames can travel 10 meters unrepeated.4) The maximum frame length is 10 octets.2. How is a MAC address represented? （4）1) four groups of eight binary digits separated by a decimal point2) four Base10 digits separated by a decimal point3) six hexadecimal digits4) twelve hexadecimal digits5) twenty-four Base10 digits3. Which of the following statements are correct about CSMA/CD? (Choose three.)（1，3，6）1) It is a media access method used in LANs.2) It is a media access method used in FDDI WANs.3) When a device needs to transmit, it checks to see if the media is available.4) A device sends data without checking media availability because all deviceshave equal access.5) Multiple devices can successfully transmit simultaneously.6) Only one device can successfully transmit at a time.4. Which devices shown in the graphic must have a MAC address? （5）1) only PC2) only router3) PC and router4) PC, hub, and router5) PC, printer, and router第七章1. Which of the following items are common to all 100BASE technologies?(Choose three.) （1，4，5）1) frame format2) media3) connectors4) timing5) multi-part encoding2. Which of the following does 1000BASE-T use to accomplish gigabit speeds onCat 5e cable? （4）1) the use of four conductors in full-duplex mode2) the use of two multiplexed pairs of wires, simultaneously3) the use of three pairs of wires for data and the fourth for stabilization andforward error correction4) the use of all four pairs of wires in full-duplex mode, simultaneously3. For which of the following is Ethernet considered the standard? (Choose three.)（1，4，5）1) inter-building connection2) mid-length voice3) video conferencing4) vertical wiring5) horizontal wiring6) diagonal wiring4. To make sure timing limitations are not violated when implementing a 10 MbpsEthernet network involving hubs or repeaters, a technician should adhere to which rule? （4）1) the 4-5-3 rule2) the 6-4-2 rule3) the 3-4-5 rule4) the 5-4-3 rule5. What is the maximum distance that 10BASE-T will transmit data before signalattenuation affects the data delivery? （1）1) 100 meters2) 185 meters3) 300 meters4) 500 meters6. When using Category 5 UTP cable, which RJ-45 pin pairs are used to exchangedata between hosts on an Ethernet network? （2）1) 1 and 2; 4 and 52) 1 and 2; 3 and 63) 3 and 6; 7 and 84) 4 and 5; 7 and 8第八章1. John has been hired as the network administrator of a local company and hasdecided to add more hubs to the company's existing network. Which of the following has been caused by John's inexperience? （1）1) collision domain extended2) an increased number of collision domains3) increased network performance4) increased bandwidth5) extended bandwidth2. "CompA" is trying to locate a new computer named "CompB" on the network.Which of the following does "CompA" broadcast to find the MAC address of "CompB"? （2）1) MAC request2) ARP request3) ping4) Telnet5) proxy ARP3. Which of the following is a term associated with replacing hubs with switchesto increase the number of collision domains? （3）1) encapsulation2) latency3) segmentation4) layered model5) broadcast domain6) Extended4. The accumulation of traffic from which of the following can cause a networkcondition called broadcast radiation? (Choose three.) （3，5，6）1) anonymous FTP servers2) telnet sessions3) video over IP applications4) NAS services5) ARP requests6) RIP updates5. Which of the following describes the use of Spanning Tree Protocol (STP)? （4）1) resolve routing loops2) eliminate Split Horizon errors3) limit collisions4) resolve switching loops6. Which term describes the delay in time that occurs when a frame leaves itssource device and reaches its destination? （4）1) collision2) backoff3) attenuation4) latency5) broadcast7. Based on the graphic above, which of the following occurs as each host systemcomes on line in the topology? （2）1) The switch sends its MAC address to each host.2) The switch adds MAC address to the bridge table as each host sends a frame.3) Each host exchanges MAC addresses with each other.4) The switch listens for data traffic to block since the switch lacks an IP address. 8. Which devices segment collision domains? (Choose two.) （2，3）1) transceiver2) router3) switch4) hub5) media9. Which protocol is used to eliminate switching loops? （3）1) Transmission Control Protocol2) Routing Information Protocol3) Spanning Tree Protocol4) Interior Gateway Routing Protocol5) Internetworking Protocol10. Refer to the exhibit. A network associate needs to establish an Ethernetconnection between Host A and Host B. However, the distance between the two hosts is further than the cabling standards allow. Which two devices that operate at the physical layer of the OSI can be used to allow Host A and Host B to communicate? （2，5）1) switch2) hub3) bridge4) router5) repeater第九章1. Which term describes an ARP response by a router on behalf of a requestinghost? （3）1) ARP2) RARP3) Proxy ARP4) Proxy RARP2. Which protocol functions at the internet layer of the TCP/IP protocol suite? （4）1) File Transfer Protocol (FTP)2) Trivial File Transfer Protocol (TFTP)3) Transmission Control Protocol (TCP)4) Internet Protocol (IP)5) User Datagram Protocol (UDP)6) Simple Mail Transport Protocol (SMTP)3. Which of these workstation installation and setup tasks are concerned withnetwork access layer functions? (Choose two.) （2，4）1) configuring the e-mail client2) installing NIC drivers3) configuring IP network settings4) connecting the network cable5) using FTP to download application software updates4. Which part of an IP address identifies a specific device on a network? （4）1) first two octets2) third and fourth octets3) network portion4) host portion5) only the fourth octet5. Which of the following are features of the Internet Protocol (IP)? (Choose two.)（1，3）1) It is the most widely implemented global addressing scheme.2) It allows two hosts to share a single address on a local area network.3) It is a hierarchical addressing scheme allowing addresses to be grouped.4) It is only locally significant, used primarily on local area networks.6. Which of the following are useable Class A IP addresses with a default subnetmask? (Choose three.) （2，3，5）1) 127.0.39.12) 111.9.28.303) 123.1.2.1324) 128.50.38.25) 105.1.34.16) 0.23.92.37. Which application layer protocols use UDP at the transport layer? (Choose two.)（2，4）1) FTP2) SNMP3) Telnet4) DHCP5) SMTP第十章1. Which OSI layer encapsulates data into packets? （3）1) session2) transport3) network4) data link2. Which OSI layer defines the functions of a router? （3）1) physical2) data link3) network4) transport5) session3. Which of the following are Cisco proprietary routing protocols? (Choose two.)（2，6）1) RIPv22) IGRP3) OSPF4) BGP5) RIPv16) EIGRP4. A company with a Class B license needs to have a minimum of 1,000 subnetswith each subnet capable of accommodating 50 hosts. Which mask below is the appropriate one? （4）1) 255.255.0.02) 255.255.240.03) 255.255.255.04) 255.255.255.1925) 255.255.255.2245. A small company has a class C network license and needs to create five usablesubnets, each subnet capable of accommodating at least 20 hosts. Which of the following is the appropriate subnet mask? （3）1) 255.255.255.02) 255.255.255.1923) 255.255.255.2244) 255.255.255.2406. When a network administrator applies the subnet mask 255.255.255.248 to aClass A address, for any given subnet, how many IP addresses are available to be assigned to devices? （6）1) 10222) 5103) 2544) 1265) 306) 67. Host A is assigned the IP address 10.18.97.55 /21. How many more networkdevices can be assigned to this subnetwork if Host A is the only one that has an IP address assigned so far? （4）1) 2542) 5093) 10214) 20455) 40946) 81908.Refe r to the exhibit. The network administrator wants to create a subnet for thepoint-to-point connection between the two routers. Which subnetwork mask would provide enough addresses for the point-to-point link with the least number of wasted addresses?1) 255.255.255.1922) 255.255.255.2243) 255.255.255.2404) 255.255.255.2485) 255.255.255.2529. What is the correct number of usable subnetworks and hosts for the IP networkaddress 192.168.35.0 subnetted with a /28 mask?1) 6 networks / 64 hosts2) 14 networks / 32 hosts3) 14 networks / 14 hosts4) 30 networks / 64 hosts10. Which subnet masks would be valid for a subnetted Class B address? (Choosetwo.) （5，6）1) 255.0.0.02) 255.254.0.03) 255.224.0.04) 255.255.0.05) 255.255.252.06) 255.255.255.19211. Refer to the exhibit. How will the Fohi router dynamically learn routes to the192.168.16.16/28, 192.168.16.32/28, and 192.168.16.48/28 subnetworks? （3）1) with a static route2) with a routed protocol3) with a routing protocol4) with a directly connected route12. How many broadcast domains are shown in the diagram? （1）1) three2) four3) five4) six5) seven6) eight13. How many collision domains are shown in the diagram? （5）1) three2) four3) five4) six5) seven6) eight14. A router interface has been assigned an IP address of 172.16.192.166 with amask of 255.255.255.248. To which subnet does the IP address belong?1) 172.16.0.02) 172.16.192.03) 172.16.192.1284) 172.16.192.1605) 172.16.192.1686) 172.16.192.17615. Refer to the exhibit. Host A is sending data to Host B. Once R2 determines thatdata from Host A must be forwarded to R1 to reach Host B, which layer of the OSI model will R2 use to address and build the frames destined for R1?1) physical2) data link3) network4) transport5) session6) presentation16. Which type of address is 192.168.170.112/28?1) host address2) subnetwork address3) broadcast address4) multicast address17. Which type of address is 223.168.17.167/29?1) host address2) multicast address3) broadcast address4) subnetwork address18. Which combination of network id and subnet mask correctly identifies all IPaddresses from 172.16.128.0 through 172.16.159.255?1) 172.16.128.0 255.255.255.2242) 172.16.128.0 255.255.0.03) 172.16.128.0 255.255.192.04) 172.16.128.0 255.255.224.05) 172.16.128.0 255.255.255.19219. Refer to the exhibit. The internetwork in the exhibit has been assigned the IPaddress 172.20.0.0. What would be the appropriate subnet mask to maximize the number of networks available for future growth?1) 255.255.224.02) 255.255.240.03) 255.255.248.04) 255.255.252.05) 255.255.254.06) 255.255.255.0第十一章1. If a network administrator needed to download files from a remote server, whichprotocols could the administrator use to remotely access those files? (Choose two.) （3，5）1) NFS2) ASCII3) TFTP4) IMAP5) FTP6) UDP2. What is established during a connection-oriented file transfer betweencomputers? (Choose two.) （2，5）1) a temporary connection to establish authentication of hosts2) a connection used for ASCII or binary mode data transfer3) a connection used to provide the tunnel through which file headers aretransported4) a command connection which allows the transfer of multiple commands directlyto the remote server system5) a control connection between the client and server3. Which of the following protocols are used for e-mail transfer between clientsand servers? (Choose three.) （3，4，5）1) TFTP2) SNMP3) POP34) SMTP5) IMAP46) postoffice4. Which type of institution does the domain suffix .org represent? （4）1) government2) education3) network4) non-profit5. Which of the following services is used to translate a web address into an IPaddress? （1）1) DNS2) WINS3) DHCP4) Telnet6. Which part of the URL http://www.awsb.ca/teacher gives the name of thedomain? （4）1) www2) http://3) /teacher4) awsb.ca7. Which protocols are TCP/IP application layer protocols? (Choose two.) （2，4）1) UDP2) FTP3) IP4) SMTP5) TCP8. What are three characteristics of the TCP protocol? (Choose three.) （3，4，6）1) has less overhead than UDP2) is used for IP error messages3) forces the retransmission undelivered packets4) creates a virtual session between end-user applications5) carries the IP address of destination host in the TCP header6) is responsible for breaking messages into segments and reassembling9. Two peer hosts are exchanging data using TFTP. During the current session, adatagram fails to arrive at the destination. Which statement is true regarding the retransmission of the datagram? （2）1) Datagram retransmission requires user authentication.2) Datagram retransmission is controlled by the application.3) Datagram retransmission relies on the acknowledgements at transport layer.4) Datagram retransmission occurs when the retransmission timer expires in thesource host.案例学习1. 子网计算练习：Answer2. 子网号及广播地址计算练习Answer3. 子网规划练习：已知：给定一个C类地址201.16.5.0/24。

第七章 CCNA第二学期 Exploration: 路由协议和概念 (版本 4.0)(2010-12-20 19:19:52)转载▼标签：it 分类：2010｜CCNA2官方试题--路由ERouting Chapter 7 - CCNA Exploration: 路由协议和概念(版本 4.0)1请参见图示。

如果所有路由器都运行 RIP 第 2 版，为什么没有 192.168.1.32/27网络的路由Rip 第 2 版不会在更新中发送子网掩码。

路由器 A 并未将 RIP 设置为路由协议。

Rip 第 2 版默认将自动总结路由。

路由器 B 未设置为通告 192.168.1.64/30 网络。

2请参见图示。

下列哪个路由器上的哪条命令可让 Router1 获知 192.168.0.0/20 网络？Router1(config)# ip classlessRouter1(config-router)# no passive-interface serial 0/1/1Router2(config-router)# version 2Router2(config-router)# neighbor 10.0.0.23哪两项是选择实施 RIP 第 2 版而不是 RIP 第 1 版的原因？（选择两项。

）RIP 第 2 版支持 VLSM。

RIP 第 2 版支持 16 台以上的路由器。

RIP 第 2 版支持有类（而不是无类）路由RIP 第 2 版支持路由更新验证。

RIP 第 2 版支持多区域。

RIP 第 2 版使用 Dijkstra 算法而不是贝尔曼-福特算法。

4RIP v1 和 RIP v2 的相似点有哪些？（选择三项。

）两者都使用跳数作为度量。

两者对无穷距离使用相同的度量值。

两者都向邻居广播其更新。

两者都在更新中发送子网掩码信息。

两者都对更新来源进行身份验证。

两者都使用水平分割来防止路由环路。

5请参见图示。

路由器 East 和 West 被配置为使用 RIPv1。

以下是针对您未获得满分的试题给出的反馈。

某些交互式试题可能不显示您的答案。

分项分数：1哪个接口是包含用于管理24 个端口以太网交换机的IP 地址的默认位置？正确响应您的响应VLAN 1Fa0/0Fa0/1连接到默认网关的接口VLAN 99此试题参考以下领域的内容：Routing and Switching Essentials• 2.1.1 使用初始设置配置交换机2下列关于使用全双工快速以太网的陈述中，哪三项是正确的？（请选择三项。

）正确响应您的响应通过双向数据流改善了性能。

由于禁用了设备上的冲突检测功能，因此性能得到了改善。

节点以全双工单向数据流运行。

由于网卡可以检测到冲突，因此性能得到了改善。

全双工快速以太网在两个方向上提供100% 的效率。

由于网卡能更快速地处理帧，因此延迟减少了。

此试题参考以下领域的内容：Routing and Switching Essentials• 2.1.2 配置交换机端口3使用mdix auto 配置命令会对交换机上的以太网接口产生什么影响？正确响应您的响应自动检测双工设置自动检测接口速度自动检测铜电缆类型自动将第一个检测到的MAC 地址分配给接口此试题参考以下领域的内容：Routing and Switching Essentials• 2.1.2 配置交换机端口4在Cisco IOS 软件无法加载的情况下，网络管理员需要哪种类型的电缆将PC 与交换机连接才能恢复它？正确响应您的响应同轴电缆控制台电缆交叉电缆直通电缆因为交换机上没有运行Cisco IOS 软件，所以管理员需要使用控制台电缆将PC 连接到交换机控制台端口，比便将来自PC 的软件转移到交换机。

此试题参考以下领域的内容：Routing and Switching Essentials• 2.1.1 使用初始设置配置交换机5在对连接问题进行故障排除时，网络管理员发现交换机端口状态LED 在绿色和琥珀色之间跳转。

CCNA2.Chapter 2 (Form A)1What are two advantages of static routing over dynamic routing? (Choose two.)Static routing is more secure because it does not advertise over the network.Static routing scales well with expanding networks.Static routing requires very little knowledge of the network for correct implementation.Static routing uses fewer router resources than dynamic routing.Static routing is relatively easy to configure for large networks.Static routing requires a thorough understanding of the entire network for proper implementation. It can be prone to errors and does not scale well for large networks. Static routing uses fewer router resources, because no computing is required for updating routes. Static routing can also be more secure because it does not advertise over the network.This item references content from the following areas: Routing Protocols2.1.1 Static Routing2Refer to the exhibit.Which is the best way for PC A and PC B to successfully communicate with sites on theInternet?Configure a static route from R1 to ISP and a dynamic route from ISP to R1.Configure a default route from R1 to ISP and a static route from ISP to R1.Configure a dynamic route from R1 to ISP and a static route from ISP to R1.Configure a routing protocol between R1 and ISP and advertise all the routes.Two routes have to be created: a default route in R1 to reach ISP and a static route in ISP to reach R1 for the return traffic. This is abest solution once PC A and PC B belong to stub networks. Moreover, static routing consumes less bandwidth than dynamic routing.This item references content from the following areas:Routing Protocols∙ 2.1.1 Static Routing3 What type of route allows a router to forward packets even though its routing table containsno specific route to the destination network?dynamic routedefault routedestination routegeneric routeThis item references content from the following areas:Routing Protocols∙ 2.1.2 Types of Static Routes4 Why would a floating static route be configured with an administrative distance that is higherthan the administrative distance of a dynamic routing protocol that is running on the same router?to be used as a backup routeto load-balance the trafficto act as a gateway of last resortto be the priority route in the routing tableBy default, dynamic routing protocols have a higher administrative distance than static routes. Configuring a static route with a higher administrative distance than that of the dynamic routing protocol will result in the dynamic route being used instead of the static route. However, should the dynamically learned route fail, then the static route will be used as a backup.This item references content from the following areas:Routing Protocols∙ 2.1.2 Types of Static Routes5 Which type of static route that is configured on a router uses only the exit interface?recursive static routedirectly connected static routefully specified static routedefault static routeWhen only the exit interface is used, the route is a directly connected static route. When the next-hop IP address is used, the route is a recursive static route. When both are used, it is a fully specified static route.This item references content from the following areas:Routing Protocols∙ 2.2.1 Configure IPv4 Static Routes6Refer to the graphic. Whichcommand would be used on router A to configure a static route to direct traffic from LAN A that is destined for LAN C?A(config)# ip route 192.168.4.0 255.255.255.0 192.168.5.2A(config)# ip route 192.168.4.0 255.255.255.0 192.168.3.2A(config)# ip route 192.168.5.0 255.255.255.0 192.168.3.2A(config)# ip route 192.168.3.0 255.255.255.0 192.168.3.1A(config)# ip route 192.168.3.2 255.255.255.0 192.168.4.0The destination network on LAN C is 192.168.4.0 and the next-hop address from the perspective of router A is 192.168.3.2.This item references content from the following areas:Routing Protocols∙ 2.2.1 Configure IPv4 Static Routes7 The network administrator configures the router with the ip route 172.16.1.0 255.255.255.0172.16.2.2 command. How will this route appear in the routing table?C 172.16.1.0 is directly connected, Serial0/0S 172.16.1.0 is directly connected, Serial0/0C 172.16.1.0 [1/0] via 172.16.2.2S 172.16.1.0 [1/0] via 172.16.2.2This item references content from the following areas:Routing Protocols∙ 2.2.1 Configure IPv4 Static Routes8Refer to the exhibit. What two commands willchange the next-hop address for the 10.0.0.0/8 network from 172.16.40.2 to 192.168.1.2?(Choose two.)A(config)# no network 10.0.0.0 255.0.0.0 172.16.40.2A(config)# no ip address 10.0.0.1 255.0.0.0 172.16.40.2A(config)# no ip route 10.0.0.0 255.0.0.0 172.16.40.2A(config)# ip route 10.0.0.0 255.0.0.0 s0/0/0A(config)# ip route 10.0.0.0 255.0.0.0 192.168.1.2This item references content from the following areas: Routing Protocols2.2.1 Configure IPv4 Static Routes9 The output of the show ip routecommand contains the following entry:S 10.2.0.0 [1/0] via 172.16.2.2.What value is indicated by the 1 in the [1/0] portion of the output?metricnumber of hopsadministrative distanceinterface ID through which the network can be reachedIn the routing table entry, S 10.2.0.0 [1/0] via 172.16.2.2, the numbers inside the bracket indicate the administrative distance and metric respectively.This item references content from the following areas:Routing Protocols∙ 2.2.1 Configure IPv4 Static Routes10Refer to the exhibit. The network administrator needs to configure a default route on the Border router. Whichcommand would the administrator use to configure a default route that will require the least amount of router processing when forwarding packets?Border(config)# ip route 0.0.0.0 0.0.0.0 198.133.219.5Border(config)# ip route 0.0.0.0 0.0.0.0 198.133.219.6Border(config)# ip route 0.0.0.0 0.0.0.0 s0/0/1Border(config)# ip route 0.0.0.0 0.0.0.0 s0/0/0The default route configured with the next-hop option requires a recursive lookup.This item references content from the following areas:Routing Protocols∙ 2.2.2 Configure IPv4 Default Routes11Refer to the exhibit. What command would be used to configure a static route on R1 so that traffic from both LANs can reach the 2001:db8:1:4::/64 remote network?ipv6 route ::/0 serial0/0/0ipv6 route 2001:db8:1:4::/64 2001:db8:1:3::1ipv6 route 2001:db8:1:4::/64 2001:db8:1:3::2ipv6 route 2001:db8:1::/65 2001:db8:1:3::1To configure an IPv6 static route, use the ipv6 route command followed by the destination network. Then add either the IP address ofthe adjacent router or the interface R1 will use to transmit a packet to the 2001:db8:1:4::/64 network.This item references content from the following areas:Routing Protocols2.2.3 Configure IPv6 Static Routes12Refer to the exhibit. Whichdefault static route command would allow R1 to potentially reach all unknown networks onthe Internet?R1(config)# ipv6 route 2001:db8:32::/64 G0/0R1(config)# ipv6 route ::/0 G0/0 fe80::2R1(config)# ipv6 route ::/0 G0/1 fe80::2R1(config)# ipv6 route 2001:db8:32::/64 G0/1 fe80::2To route packets to unknown IPv6 networks a router will need an IPv6 default route. The static route ipv6 route ::/0 G0/1 fe80::2 will match all networks and send packets out the specified exit interface G0/1 toward R2.This item references content from the following areas: Routing Protocols∙ 2.2.4 Configure IPv6 Default Routes13 Which two statements describe classful IP addresses? (Choose two.)It is possible to determine which class an address belongs to by reading the first bit.The number of bits used to identify the hosts is fixed by the class of the network.Only Class A addresses can be represented by high-order bits 100.Up to 24 bits can make up the host portion of a Class C address.All subnets in a network are the same size.Three of the five classes of addresses are reserved for multicasts and experimental use.This item references content from the following areas: Routing Protocols∙ 2.3.1 Classful Addressing14 A company has several networks with the following IP address requirements: IP phones - 50 PCs - 70IP cameras - 10wireless access points - 10 network printers - 10network scanners - 2Which block of addresses would be the minimum to accommodate all of these devices if each type of device was on its own network?172.16.0.0/25172.16.0.0/24172.16.0.0/23172.16.0.0/22The network for the PCs would require a subnet mask of /25 in order to accommodate 70 devices. That network could use IP addresses 0 through 127. Phones require a subnet mask of /26 for 50 devices (addresses 128-191). Three /28 networks are needed in order to accommodate cameras, APs, and printers. The network scanner network can use a /30. A block of addresses with a mask of/24 will accommodate this site as the minimum amount needed.This item references content from the following areas:Routing Protocols∙ 2.3.3 VLSM15 What does VLSM allow a network administrator to do?utilize one subnet mask throughout a hierarchical networkutilize multiple routing protocols within an autonomous systemutilize one dynamic routing protocol throughout the entire networkutilize multiple different subnet masks in the same IP address spaceutilize one public IP address to translate multiple private addressesThis item references content from the following areas:Routing Protocols∙ 2.3.3 VLSM16 What would be the best summary route for the following networks?10.50.168.0/2310.50.170.0/2310.50.172.0/2310.50.174.0/2410.50.160.0/2210.50.164.0/2310.50.168.0/1610.50.168.0/2110.50.168.0/2210.50.168.0/23Write 168, 170, 172, and 174 (the third octet where things start changing) in binary. Look at the 1s and 0s pattern. Notice the digits on the right where the change occurs. Draw a line after the column of 1s or 0s that is the last column that remains constant (exactly the same) to the left of that line. This would be immediately after the "8s" column, meaning that the 128, 64, 32, 16, and 8 columns all have the same pattern of 1s and 0s. Because this is in the third octet and the mask is /16 for the first two octets, add 5 more to the mask for the columns that are consistently the same in the third octet (/21).This item references content from the following areas:Routing Protocols2.4.1 Configure IPv4 Summary Routes17 What is a valid summary route for IPv6 networks 2001:0DB8:ACAD:4::/64,2001:0DB8:ACAD:5::/64, 2001:0DB8:ACAD:6::/64, and 2001:0DB8:ACAD:7::/64?2001:0DB8:ACAD:0000::/632001:0DB8:ACAD:0000::/642001:0DB8:ACAD:0004::/622001:0DB8:ACAD:0004::/63The IPv6 networks with the fourth octet of hex characters converted to binary are:2001:0DB8:ACAD:0000000000000100::/642001:0DB8:ACAD:0000000000000101::/642001:0DB8:ACAD:0000000000000110::/642001:0DB8:ACAD:0000000000000111::/64The common bits are 2001:0DB8:ACAD:00000000000001. Then add zeros to determine the network summarized address, giving 2001:0DB8:ACAD:0000000000000100. Convert this to hexadecimal and count the number of left-most matching bits. The summarized address will be 2001:0DB8:ACAD:0004::/62.This item references content from the following areas:Routing Protocols∙ 2.4.2 Configure IPv6 Summary Routes18Refer to the exhibit. The network engineer for the company that is shown wants to use the primary ISP connection for all external connectivity. The backup ISP connection is used only if the primary ISP connection fails. Which set of commands would accomplish this goal?ip route 198.133.219.24 255.255.255.252ip route 64.100.210.80 255.255.255.252ip route 198.133.219.24 255.255.255.252ip route 64.100.210.80 255.255.255.252 10ip route 0.0.0.0 0.0.0.0 s0/0/0ip route 0.0.0.0 0.0.0.0 s0/1/0ip route 0.0.0.0 0.0.0.0 s0/0/0ip route 0.0.0.0 0.0.0.0 s0/1/0 10A static route that has no administrative distance added as part of the command has a default administrative distance of 1. The backuplink should have a number higher than 1. The correct answer has an administrative distance of 10. The other quad zero route wouldload balance packets across both links and both links would appear in the routing table. The remaining answers are simply static routes (either a default route or a floating static default route).This item references content from the following areas:Routing Protocols∙ 2.4.3 Configure Floating Static Routes19 Which three IOS troubleshooting commands can help to isolate problems with a static route?(Choose three.)show versionpingtracertshow ip routeshow ip interface briefshow arpThe ping, show ip route, and show ip interface brief commands provide information to help troubleshoot static routes. Showversion does not provide any routing information. The tracert command is used at the Windows command prompt and is not an IOS command. The show arp command displays learned IP address to MAC address mappings contained in the Address ResolutionProtocol (ARP) table.This item references content from the following areas:Routing Protocols2.5.2 Troubleshoot IPv4 Static and Default Route Configuration20Refer to the exhibit. The small company shown uses static routing. Users on the R2 LAN have reported a problem with connectivity. What is the issue?R2 needs a static route to the R1 LANs.R1 and R2 must use a dynamic routing protocol.R1 needs a default route to R2.R1 needs a static route to the R2 LAN.R2 needs a static route to the Internet.R1 has a default route to the Internet. R2 has a default route to R1. R1 is missing a static route for the 10.0.60.0 network. Any trafficthat reached R1 and is destined for 10.0.60.0/24 will be routed to the ISP.This item references content from the following areas:Routing Protocols∙ 2.5.2 Troubleshoot IPv4 Static and Default Route Configuration21 What happens to a static route entry in a routing table when the outgoing interface is notavailable?The route is removed from the table.The router polls neighbors for a replacement route.The route remains in the table because it was defined as static.The router redirects the static route to compensate for the loss of the next hop device.This item references content from the following areas:Routing Protocols∙ 2.5.2 Troubleshoot IPv4 Static and Default Route Configuration22 The PT initialization was skipped. You will not be able to view the PT activity.Open the PT activity. Perform the tasks in the activity instructions and then answer the question. What is the name of the web server that is displayed in the webpage?Main-WebserverWWW-ServerWebserver10MNSRVStatic routes can be configured by using the syntax router(config)# ip route prefix mask {ip-address | exit-intf}. In this case, the command to be issued would be router(config)# ip route 192.168.3.0 255.255.255.0 192.168.2.2.This item references content from the following areas:Routing Protocols∙ 2.2.1 Configure IPv4 Static Routes23 The PT initialization was skipped. You will not be able to view the PT activity.Open the PT Activity. Perform the tasks in the activity instructions and then answer the question.What IPv6 static route can be configured on router R1 to make a fully converged network?ipv6 route 2001:db8:10:12::/64 S0/0/1ipv6 route 2001:db8:10:12::/64 S0/0/0ipv6 route 2001:db8:10:12::/64 2001:db8:10:12::1ipv6 route 2001:db8:10:12::/64 2001:db8:32:77::1To reach the remote network, R1 will need a static route with a destination IPv6 address of 2001:db8:10:12::/64 and an exit interface ofS0/0/1. The correct static route configuration will be as follows:ipv6 route 2001:db8:10:12::/64 S0/0/1.This item references content from the following areas:Routing Protocols∙ 2.2.3 Configure IPv6 Static Routes。

CCNA考试题库中英文翻译版及答案．A. The area of overlap of the two cells represents a basic service set (BSS).A. 两个 cells的overlap的区域描述了一个basic service setB. The network diagram represents an extended service set (ESS).B. 网络描述了一个extended service setC. Access points in each cell must be configured to use channel 1.C. 再每个CELL中的AP必须被配置成使用channel 1D. The area of overlap must be less than 10% of the area to ensure connectivity.D. 为了确保连通性,重叠区域必须小于10%E. The two APs should be configured to operate on different channels.E. 两个访问点应该被配置成工作在不同的频道Answer: BE6. The command frame-relay map ip 10.121.16.8 102 broadcast was entered on the router.Which ofthe following statements is true concerning this command?6.路由器上输入命令frame-relay map ip 10.121.16.8 102 broadcast，以下选项正确的是?A. This command should be executed from the global configuration mode.A.该命令应该在全局配置模式下被执行B. The IP address 10.121.16.8 is the local router port used to forward data.B.IP地址10.121.16.8是本地路由器用来转发数据的接口C. 102 is the remote DLCI that will receive the information.C.102是远端的DLCI它将接受信息。