CCNA-Exploration-网络基础知识-第二章练习及答案

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。

yy1 ・ Refer to the exhibit・ Identify the devices labeled A, B, C, and D in the network physical documentation. 匚A=bridge, B=switch, C=router, D=hubK A=bridge, B=hub, C=router, D=switchC A=bridge, B=router, C=hub, D=switchc A=hub, B=bridge, C=router, D=switch2 The central hub has malfunctioned in the network. As a result, the entire network is down. Which type of physical network topology is implemented?匚busE starC ring匚mesh3. A switch has failed in the network. As a result, only one segment of the network is down. Which type of physical network topology is implemented?C busC ring匚starE extended star4. Which three features apply to LAN connections? (Choose three.)厂operate using serial in terfacesV make network connection using a hubV limited to operation over small geographic areas厂 provide part-time connectivity to remote servicesV typically operate under local administrative control厂provide lower bandwidth services compared to WANs5. What is one advantage of defining network communication by the seven layers of the OSI model? 【:It in creases the ban dwidth of a n etwork.E It makes networking easier to learn and understand・It eliminates many protocol restrictions.匚It increases the throughput of a network.c It reduces the need for testing network connectivity.6. What makes it easier for different networking vendors to design software and hardware that willin teroperate?E OSI modelc proprietary desig ns匚IP addressing schemec standard logical topologies匚standard physical topologies7. Which term describes the process of adding headers to data as it moves down OSI layers?匚division匚encoding匚separation匚segmentationE encapsulation8. What is the term used to describe the transport layer protocol data unit?匚bits c packetsE segments匚framesc data streams9. Which of the following are layers of the TCP/IP model? (Choose three.)▽ Applicati onr PhysicalV Internet0 Network Access厂Prese ntation10. Which of the following are data link layer encapsulation details? (Choose two.)0 A header and trailer are added・厂Data is con verted into packets ・V Packets are packaged into frames・厂Frames are divided into segments.厂Packets are changed into bits for Internet travel.11. Which layer of the OSI model provides network services to processes in electronic mail and file transfer programs?匚data link匚transport匚n etworkE application12. Which two features apply to WAN connections? (Choose two.)V operate using serial interfacesP make network connection using a hub厂limited to operation over small geographic areasI- typically operate under local administrative control▽provide lower bandwidth services compared to LANs13. Which of the following are ways that bandwidth is commonly measured? (Choose three.)厂GHzps▽kbpsV Mbps厂Nbps厂MHzpsV Gbps14. Refer to the following list. Choose the correct order of data encapsulation when a device sends information. segments bits packetsdata frames匚1 -3-5-4-2C 2- 1-3-5-4C 2-4-3-5-1匚4-3-1-2-5E 4-1 -3-5-2C 3-5-1-2-415. Which of the following are factors that determine throughput? (Choose two.)厂types of passwords used on servers厂type of Layer 3 protocol usedV n etwork topologywidth of the network cable0 number of users on the network16. Refer to the exhibit・ Which column shows the correct sequenee of OSI model layers?E D17. Which layer of the OSI model provides connectivity and path selection between two end systems where routing occurs?c physical layer匚data link layerE network layer匚transport layer18. Which best describes the function of the physical layer?E Defines the electrical and functional specifications for the link between end systems・匚Provides reliable transit of data across a physical link.匚Provides connectivity and path selection between two end systems・匚Concerned with physical addressing, network topology and media access.。

1下列有关在交换机上发出的 banner login "Authorized personnel Only" 命令的说法中哪项正确？Option 2该命令应在特权执行模式下输入。

该命令会导致用户登录前显示 Authorized personnel Only 消息。

该命令会生成并显示错误消息 % Ambiguous command: "banner motd" ”。

将该命令输入交换机后，屏幕上会显示 End with the character “%”消息。

2哪种命令行界面 (CLI) 模式允许用户配置诸如主机名和口令等交换机参数？Option 3用户执行模式特权执行模式全局配置模式接口配置模式3网络管理员通过 CLI 输入一个命令，该命令需要几个参数。

交换机的响应为 "% Incomplete command"。

管理员不记得缺失了什么参数。

管理员可通过什么方法在线代理|网页代理|代理网页|来获取参数信息？Option 2向最后一个参数末尾附加一个问号 (?)向最后一个参数末尾附加一个空格，然后附加一个问号 (?)按 Ctrl-P 显示参数列表按 Tab 键显示可用的选项4请参见图示。

图中显示了 show running-config 命令的部分输出。

此交换机的使能口令是 "cisco"。

从图中所示的输出可得出什么结论？Option 3默认情况下会加密使能口令。

所有加密口令均采用 MD5 哈希算法加密。

在此配置中，已配置的所有线路模式口令都会被加密。

此行代表最安全的特权执行模式口令。

在线代理|网页代理|代理网页|5采用 CSMA/CD 的网络中发生冲突时，需要传输数据的主机在回退时间到期后做何反应？Option 1主机恢复传输前侦听模式。

造成冲突的主机优先发送数据。

造成冲突的主机重新传输最后 16 个帧。

主机延长其延迟时间以便快速传输。

1第 3 层头部包含的哪一项信息可帮助数据传输？端口号设备物理地址目的主机逻辑地址虚拟连接标识符标题描述最高分值1 correctness of response2 points for Option 30 points for any other option2此试题参考以下领域的内容：CCNA Exploration: 网络基础知识∙ 2.5.3 数据通过网际网络2IP 依靠 OSI 哪一层的协议来确定数据包是否已丢失并请求重传？应用层表示层会话层传输层标题描述最高分值1 correctness of response2 points for Option 40 points for any other option2此试题参考以下领域的内容：CCNA Exploration: 网络基础知识∙ 5.1.4 IPv4 协议 - 尽力3请参见图示。

图中所示为在各层添加的头部。

哪一层会添加目的进程号和源进程号以确保将数据传递到正确的应用程物理层数据链路层网络层传输层标题描述最高分值1 correctness of response2 points for Option 4 20 points for any other option此试题参考以下领域的内容：CCNA Exploration: 网络基础知识∙ 2.5.1 网络中的编址4下列哪一个 OSI 层使用头部信息将数据段重组为数据流？应用层网络层表示层会话层传输层标题描述最高分值1 correctness of response2 points for Option 50 points for any other option2此试题参考以下领域的内容：CCNA Exploration: 网络基础知识∙ 4.1.2 控制会话5请参见图示。

图中所示为客户端之间发送电子邮件的过程。

从下列选项中选择正确标识图中各编号阶段使用的组件或1.MUA2.MDA3.MTA4.SMTP5.MTA6.POP7.MDA8.MUA1.MUA2.POP3.MDA4.SMTP5.MTA6.MDA7.SMTP8.MUA1.MUA2.POP3.SMTP4.MDA5.MTA6.SMTP7.POP8.MUA1.MDA2.SMTP3.MTA4.SMTP5.MTA6.MUA7.POP8.MDA1.MUA2.SMTP3.MTA4.SMTP5.MTA6.MDA7.POP8.MUA标题描述最高分值1 correctness of response2 points for Option 50 points for any other option2此试题参考以下领域的内容： CCNA Exploration: 网络基础知识∙3.3.3 电子邮件服务及 SMTP/POP 协议6某主机正在网络上传输视频。

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。

版路由协议和概念 (ERouting Chapter 1 - CCNA Exploration: 本口令可用于限制对1 Cisco IOS 所有或部分内容的访问。

请选择可以用口令保护的模式和接口。

（选择三项。

）VTY 接口控制台接口特权执行模式路由器从相连的以太网接口收到消息后，会更改哪项报头地址，再将消息从另一个接口发送出去？2层源地址和目的地址第 23相连网络上的主机地址。

从路由器 ping 请参见图示。

网络管理员已经为路由器连接到直连网络的接口配置了如图所示的 IPping 都会遭到失败。

此问题最可能的原因是什么？口之间相互no shutdown 命令启用接口。

必须使用4B A ping 主机。

当 R4 收到对以太网接口的 ping 时，哪两块报头信息包括在内？（选择两项。

）请参见图示。

主机地址：目的 IPMAC 地址：目的。

要将配置更改保存到 Router1 NVRAM5，应该执行哪一条命令？网络管理员刚把新配置输入Router1# copy running-config startup-config6站点建立连接？（选择 Melbourne 路由器上发出以下哪条配置命令才能与 Sydney 您需要配置图中所示的串行连接，必须在．Sydney(config-if)# ip addressSydney no shutdownclock rate 56000Sydney(config-if)#7请参见图示。

从路由器的运行配置输出可得出什么结论？显示的命令决定了路由器的当前运行情况。

8无法与主机 1 通信。

导致此问题的原因是什么？请参见图示。

在主机 2 连接到 LAN 上的交换机后，主机 2和主机 1 2 位于不同的网络中。

主机输入以下命令的作用是什么？9R1(config)# line vty 0 4password check123R1(config-line)#loginR1(config-line)#Telnet 连接该路由器时使用的口令设置通过以下哪一项正确描述了路由器启动时的顺序？10IOS、应用配置加载 bootstrap、加载11加载配置文件时的默认顺序是怎样的？NVRAM、TFTP、CONSOLE12请参见图示。

1. Refer to the exhibit. Identify the devices labeled A, B, C, and D in the network physical documentation.A=bridge, B=switch, C=router, D=hubA=bridge, B=hub, C=router, D=switchA=bridge, B=router, C=hub, D=switchA=hub, B=bridge, C=router, D=switch2. The central hub has malfunctioned in the network. As a result, the entire network is down. Which type of physical network topology is implemented?busstarringmesh3. A switch has failed in the network. As a result, only one segment of the network is down. Which type of physical network topology is implemented?busringstarextended star4. Which three features apply to LAN connections? (Choose three.)operate using serial interfacesmake network connection using a hublimited to operation over small geographic areasprovide part-time connectivity to remote servicestypically operate under local administrative controlprovide lower bandwidth services compared to WANs5. What is one advantage of defining network communication by the seven layers of the OSI model?It increases the bandwidth of a network.It makes networking easier to learn and understand.It eliminates many protocol restrictions.It increases the throughput of a network.It reduces the need for testing network connectivity.6. What makes it easier for different networking vendors to design software and hardware that will interoperate?OSI modelproprietary designsIP addressing schemestandard logical topologiesstandard physical topologies7. Which term describes the process of adding headers to data as it moves down OSI layers?divisionencodingseparationsegmentationencapsulation8. What is the term used to describe the transport layer protocol data unit?bitspacketssegmentsframesdata streams9. Which of the following are layers of the TCP/IP model? (Choose three.)ApplicationPhysicalInternetNetwork AccessPresentation10. Which of the following are data link layer encapsulation details? (Choose two.)A header and trailer are added.Data is converted into packets.Packets are packaged into frames.Frames are divided into segments.Packets are changed into bits for Internet travel.11. Which layer of the OSI model provides network services to processes in electronic mail and file transfer programs?data linktransportnetworkapplication12. Which two features apply to WAN connections? (Choose two.)operate using serial interfacesmake network connection using a hublimited to operation over small geographic areastypically operate under local administrative controlprovide lower bandwidth services compared to LANs13. Which of the following are ways that bandwidth is commonly measured? (Choose th ree.)GHzpskbpsMbpsNbpsMHzpsGbps14. Refer to the following list. Choose the correct order of data encapsulation when a device sends information. segments bits packetsdata frames1 - 3 - 5 - 4 - 22 - 1 -3 - 5 - 42 - 4 -3 - 5 - 14 - 3 - 1 - 2 - 54 - 1 - 3 -5 - 23 - 5 - 1 - 2 - 415. Which of the following are factors that determine throughput? (Choose two.)types of passwords used on serverstype of Layer 3 protocol usednetwork topologywidth of the network cablenumber of users on the network16. Refer to the exhibit. Which column shows the correct sequence of OSI model layers?ABCD17. Which layer of the OSI model provides connectivity and path selection between two end systems where routing occurs?physical layerdata link layernetwork layertransport layer18. Which best describes the function of the physical layer?Defines the electrical and functional specifications for the link between end systems.Provides reliable transit of data across a physical link.Provides connectivity and path selection between two end systems.Concerned with physical addressing, network topology and media access.。

数据正从源PC 发送至目的服务器。

下列陈述中，哪三项正确地说明了TCP 或UDP 在此情况下的作用？（选择三项。

）UDP 目的端口号标识了将要处理数据的服务器上的应用程序或服务。

当某项功能要求较低的网络开销时，TCP 是首选协议。

UDP 数据段封装于要在网络中传输的IP 数据包内。

源端口字段标识了将处理返回至PC 的数据的运行应用程序或服务。

TCP 源端口号标识了网络中的发送主机。

在建立与服务器间的会话时，PC 上运行的TCP 进程会随机选择目的端口。

在哪两种情况下，UDP 传输协议更优于TCP 协议？（选择两项。

）应用程序需要保证数据包完整、有序且无复制地到达。

需要采用更快的传递机制传递开销不受限应用程序无需保证数据传递目的端口号是动态的请参见图示。

工作站 A 向工作站 B 发送了一个IP 数据包。

下列哪两项陈述说明了数据包经过网络时的封装？每个路由器都会剥离数据包的第 2 层帧头。

数据包的第 2 层目的地址不发生改变。

数据包的第 3 层源地址经过每台路由器时都发生改变。

第 2 层帧头经过每台路由器时都发生改变。

每个路由器都会剥离数据包的第 3 层帧头。

此试题参考以下领域的内容：CCNA Exploration: 网络基础知识9.7.1 ARP 过程- 将IP 映射到MAC 地址请参见图示。

一台默认配置的交换机连接了四台主机。

图示为主机 A 的ARP 表。

当主机 A 要向主机 D 发送IP 数情况？主机 A 向主机 D 的MAC 地址发送了一条ARP 请求。

主机 D 向主机 A 发送了一条ARP 请求。

主机 A 向交换机发出了数据包。

交换机只向主机 D 发送了数据包，主机 D 随即响应。

主机 A 发出了广播FF:FF:FF:FF:FF:FF。

连接到交换机的所有其它主机都收到了该广播，主机 D 以其MAC 地传输层可提供哪三种服务？（选择三项。

）流量控制数据加密路径确定连接建立错误恢复比特传输数据表示OSI 模型的哪一层负责识别和丢弃损坏的帧？表示层会话层传输层网络层数据链路层物理层请参见图示。

CCNA第一学期各章习题和参考答案第二章网络通信1、TCP/IP网络接入层有何作用？A路径确定和数据包交换B数据表示、编码和控制C可靠性、流量控制和错误检测E将数据段划分为数据包2、下列哪些陈述正确指出了中间设备在网络中的作用？（选择三项）B发起数据通信D发送数据流F数据流最后的终止点3、下列哪三项陈述是对局域网(LAN) 最准确的描述？（选择三项）C LAN 中的不同网段之间一般通过租用连接的方式连接。

D此类网络的安全和访问控制由服务提供商控制。

F此类网络的每个终端通常都连接到电信服务提供商(TSP)。

004 什么是PDU？A传输期间的帧损坏B在目的设备上重组的数据C因通信丢失而重新传输的数据包005 OSI 模型哪两层的功能与TCP/IP 模型的网络接入层相同？（选择两项）018哪个应用层协议通常用于支持客户端与服务器之间的文件传输？A HTMLB HTTP D Telnet019哪个应用层协议中规定了Microsoft 网络中用于文件共享的服务？A DHCPB DNS D SMTP E Telnet020服务器上的应用层通常如何处理多客户端服务请求？A终止与服务的所有连接B拒绝与单一守护程序的多个连接C暂停当前连接，建立新连接第四章OSI传输层001下列哪两项是用户数据报协议(UDP) 的功能？（选择两项）A流量控制 D 面向连接E 序列和确认002请参见图示。

此Wireshark 捕获输出的第7 行中执行的是哪一项TCP 操作？A会话创建B 数据段重传C 数据传输D 会话断开003数据段的TCP 报头中为什么包含端口号？A指示转发数据段时应使用的正确路由器接口B 标识接收或转发数据段时应使用的交换机端口C确定封装数据时应使用的第3 层协议让接收主机转发数据到适当的应用程序E让接收主机以正确的顺序组装数据包004OSI 模型哪一层负责规范信息从源设备到目的设备准确可靠地流动？A应用层 B 表示层 C 会话层传输层 E 网络层005请参见图示。

1请参见图示。

对于发往192.168.2.0 的数据包，R2 会采取什么操作？它会丢弃数据包。

它会通过S0/0/0 接口转发数据包。

它会通过Fa0/0 接口转发数据包。

它会将数据包转发给R1。

2请参见图示。

R1 会使用哪一总结地址来向R2 通告其网络？3请参见图示。

尽管R2 已配置正确，但主机A 还是无法访问Internet。

可以在R1 上配置哪两条可让主机A 访问Internet 的静态路由？（选择两项。

）ip route .0 0.0.0.0 Fa0/0ip route .0 0.0.0.0 Fa0/1ip routeip routeip route 209.165.202.0 255.255.255.0 .14请参见图示。

网络管理员已按图示配置了R1，并且所有接口都运作正常。

但从R1 ping 172.16.1.1 时失败。

造成此问题的原因可能是什么？R1 上的串行接口配置有误。

默认路由配置有误。

必须在R1 上发出default-information originate命令。

必须在R1 上禁用自动总结。

5请参见图示。

所有接口都已编址，并且运行正常。

网络管理员在主机A 上运行了tracert命令。

得到这种输出的原因可能是什么？（选择两项。

）主机A 缺少网关或配置不正确。

主机B 缺少网关或配置不正确。

R1 的路由表中缺少192.168.1.0/24 的条目。

R2 的路由表中缺少192.168.1.0/24 的条目。

R1 的路由表中缺少192.168.2.0/24 的条目。

R2 的路由表中缺少192.168.2.0/24 的条目。

6请参见图示。

从主机A 到主机B 的ping 成功，但从主机A ping 在Internet 上正常运行的主机却失败了。

此问题的原因是什么？R1 的快速以太网接口被禁用。

其中一条默认路由配置有误。

未在这两台路由器上配置路由协议。

主机A 上尚未配置默认网关。

7 网络管理员使用RIP 路由协议在一个自治系统内实施路由。