CCNA第一册2——11章所有答案

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ccna第二章答案

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。

ccna第二章练习答案.docx

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.。

ccna2答案第十一章

第十一章CCNA 第二学期Exploration:路由协议和概念(2010-12-24 10:14:15)转载▼标分类：2010｜ CCNA2官方试题--路签：由it1窗体顶端ERouting Chapter 11 - CCNA Exploration: 路由协议和概念(版本 4.0)为形成邻接关系，OSPF 路由器之间的哪三项参数必须相等？（选择三项。

）区域idK-values度量值hello 间隔网络类型接口类型窗体底端2窗体顶端请参见图示。

图中RouterA 、RouterB 和 RouterC 的以太网接口上运行OSPF。

路由器 D 新加入网络。

置了如图所示的环回接口(Lo 0) 。

RouterD 加入网络后，OSPF DR/BDR将会发生什么情况？RouterB 将成为DR 而 RouterD 将成为BDR 。

RouterD 将成为BDR而RouterA仍然是DR 。

RouterD 将成为DR 而 RouterA 将成为BDR 。

在选举过程完成之前，RouterC 是 DR 。

RouterD 将成为DR 而 RouterB 仍然是BDR 。

在当前DR 或 BDR 失效之前， DR 或 BDR 不会发生变化。

窗体底端3窗体顶端请参见图示。

什么配置语句可以得到如图所示show ip protocols命令输出的结果？B(config)# int fa0/0B(config-if)# router-id 192.168.1.5B(config)# int lo0B(config-if)# ip address 192.168.1.5B(config)# router ospf 1B(config-router)# router-id 192.168.1.5B(config)# router ospf 1B(config-router)# ip address 192.168.1.5窗体底端4窗体顶端请参见图示。

思科CCNA题目及答案

CCNA-Cisco-Chapter11C11 An electrician has investigated your recent power problems and has suggested that they are caused by oscillation. What is the BEST solution to your problem?Move the network server to another roomReplace UTP with fiber optic cable* Rewire the electrical systemFit commercial surge suppressors2 What is another term that can be used to describe an Intermediate Distribution Frame (IDF)? work area (WA)telecommunications outlet (TO)main cross-connect (MCC)* horizontal cross-connect (HCC)3 Why is fiber optic cable commonly used as a network backbone between campus buildings?It provides a less resistive path for electrical current to flow from one building to anotherIt enhances the signals at the physical layer* It reduces the hazardous effects of electrical potential difference and lightning strikesIt is cheaper and easier to install than copper wire4 Which of the following environmental specifications are recommended for a wiring closet ? Carpeted floor; tiled walls and an inward opening doorWooden floor; brick walls and fluorescent lightingTiled floor; internal power outlets and a dropped ceiling* Raised floor; wood covered walls and an internal light switch5 What is one of the most significant causes of oscillatory noise problems on a power circuit? ??? Long wiring runsSchool photocopiersLocating power cables in elevator shaftsAir conditioners cycling on and off6 What device is best used to minimize the effects of power line sags and brownouts?A primary protection deviceA surge suppressorAn optical isolator* An uninterruptible power supply7 What causes Electrostatic Discharge (ESD)?Long power linesFaulty electrical equipment* An accumulation of static electricityAn increase in atmospheric humidity8 Which of the following problems is caused by too high a humidity level in a wiring closet? Signal degradation* Copper wire corrosionInsulation failurePower surges9 What is the ideal room temperature and relative humidity at which a wiring closet should bemaintained?* 21 degrees Celsius / 45 % relative humidity21 degrees Fahrenheit / 45 % relative humidity45 degrees Celsius / 21 % relative humidity45 degrees Fahrenheit / 21 % relative humidity10 What is the maximum length specified for 62.5/125µm multimode optical fiber run between the MDF and IDF?90 m800 m2000 m* 3000 m11 What are the three components that make up an uninterruptible power supply?* A battery, inverter and battery chargerA MOV, capacitor and diodeA generator, changeover circuit and server softwareA circuit breaker, fuse and battery12 Where does the horizontal cable extend?From the main distribution frame in the wiring closet to the vertical cross connect in the intermediate distribution frameFrom the telecommunications outlet in the work area to the horizontal cross-connect in the telecommunications closet* From the patch panel in the point of presence to the backbone connection in the customer premises equipmentFrom the telecommunications outlet in the wiring closet to the conduit in the intermediate distribution frame13 Which statement BEST describes the current flow in an electrical circuit with a DC source?* It is constant over timeIt varies over timeIt increases with timeIt decreases with time14 Why are exposed metal components normally connected to the ground, or earth, pin of a power outlet?The connection is needed to increase the resistance of the circuit to ground* If an electrical fault occurs in the equipment, the connection will reduce the chance of shock Connecting the metal to ground makes it act like an insulatorThe ground connection can act as an alternative path for controlled current flow if the neutral wire is disconnected15 What is the term used to describe a problem in an electrical system between the hot, or live, wire and the neutral wire?An isolated mode problemA ground fault problem* A common mode problemA normal mode problem16 What function does an electrical insulator perform?It completes the circuit, allowing current to flowIt reduces the resistance in an electrical circuitIt allows a short circuit to be present* It prevents uncontrolled current flow17 What is an alternative name for backbone cabling?Horizontal cabling* Vertical cablingMain cablingTrunk cabling18 Why can digital electronic equipment, such as a computer, malfunction if subjected to excessive power line noise?Logic gates are unable to correctly distinguish the noise polarityThe noise enhances the digital signal edgesThe noise replaces the digital signal* Logic gates are unable to correctly distinguish between a one and a zero19 A potential wiring closet has been identified in a building with a floor area of 930 sq. m. The distance from this closet to the furthest workstation is 127 m. How many ADDITIONAL wiring closets would need to be installed?* 012820 Why is copper considered a good conductor of electricity?* It offers a path of least resistance to current flowIt is easily formed into wiresIt is cheaper than other metalsIt reduces power line noise21 In a controlled electrical circuit, which path do electrons normally follow?From the positively charged source to ground* From the negatively charged source to a positively charged sourceFrom the more positively charged source to the less positively charged sourceFrom the negatively charged source to ground22 What is the purpose of providing a ground, or earth, connection on a wall power outlet?To reduce the resistance in the electrical circuitTo link the neutral wire to ground* To allow fault currents to flow to groundTo complete the circuit for normal current to flow23 What is a possible problem associated with multiple building grounds?They are often at the same potential with respect to each otherThey do not allow electrical current to flow between the buildingsSeparate protective devices are needed at each building* They may present a shock hazard due to different potentials24 What features should be considered when assessing a potential wiring closet?It should be secure and situated on the first (ground) floor???? It should be secure and close to the POPIt should be within 150 m of the MDF and close to an entranceIt should be an internal room and close to the electrical supply distributionC21. 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 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 layerslimit 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 detectionensures 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 encapsulation7. Which characteristic correctly refers to end devices in a network?manage data flowsoriginate data flowretime and retransmit data signalsdetermine pathways for data10. 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).12. 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 networkto identify the source and destination end devices that are communicatingto identify the processes or services that are communicating within the end devices13. What device is considered an intermediary device?file serverIP phonelaptopprinterswitch16. Which layer encapsulates the segment into packets?physicaldata linknetworktransport17. What can be identified by examining the network layer header?the destination device on the local mediathe destination host addressthe 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 controlthe 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.The process port number is added.21. 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, transport application, physical, session, transport, network, data link, presentation application, presentation, physical, session, data link, transport, network application, presentation, session, transport, network, data link, physical presentation, 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 LinkSessionC31 How does the application layer on a server usually process multiple client request for services?ceases all connections to the servicedenies multiple connections to a single daemonsuspends the current connection to allow the new connectionuses support from lower layer functions to distinguish between connections to the service2 A small home network has been installed to interconnect three computers together for gaming and file sharing. What two properties represent this network type? (Choose two.)User accounts are centralized.Security is difficult to enforce.Specialized operating system software is required.File permissions are controlled by a single computer.A computer that responds to a file sharing request is functioning as a server.3 What is the purpose of resource records in DNS?temporarily holds resolved entriesused by the server to resolve namessent by the client to during a querypasses authentication information between the server and client4 A network administrator is designing a network for a new branch office of twenty-five users. What are the advantages of using a client-server model? (Choose two.)centralized administrationdoes not require specialized softwaresecurity is easier to enforcelower cost implementationprovides a single point of failure5 What are three properties of peer-to-peer applications? (Choose three.)acts as both a client and server within the same communicationrequires centralized account administrationhybrid mode includes a centralized directory of filescan be used in client-server networksrequires a direct physical connection between devicescentralized authentication is required6 As compared to SSH, what is the primary disadvantage of telnet?not widely availabledoes not support encryptionconsumes more network bandwidthdoes not support authentication7 What is the automated service that matches resource names with the required IP address?HTTPSSHFQDNDNSTelnetSMTP8 What application layer protocol describes the services that are used for file sharing in Microsoft networks?DHCPDNSSMBSMTPTelnet9 Which two protocols are used to control the transfer of web resources from a web server to a client browser? (Choose two.)ASPFTPHTMLHTTPHTTPSIP10 What three protocols operate at the Application layer of the OSI model? (Choose three.)ARPDNSPPPSMTPPOPICMP11 Which layer of the OSI model supplies services that allow user to interface with the network?physicalsessionnetworkpresentationapplicationtransport12 Which email components are used to forward mail between servers? (Choose two.) MDAIMAPMTAPOPSMTPMUA13 What are two forms of application layer software? (Choose two.)applicationsdialogsrequestsservicessyntax14 Which statements are correct concerning the role of the MTA in handling email? (Choose three.)routes email to the MDA on other serversreceives email from the client's MUAreceives email via the POP3 protocolpasses email to the MDA for final deliveryuses SMTP to route email between serversdelivers email to clients via the POP3 protocol15 What are two characteristics of clients in data networks? (Choose two.)use daemonsinitiate data exchangesare repositories of datamay upload data to serverslisten for requests from servers16 What is the role of the OSI application layer?provides segmentation of dataprovides encryption and conversion of dataprovides the interface between the applications on either end of the network provides control of all the data flowing between the source and destination devices 17 Which application layer protocols correctly match a corresponding function? (Choose two.)DNS dynamically allocates IP addresses to hostsHTTP transfers data from a web server to a clientPOP delivers email from the client to the server email serverSMTP supports file sharingTelnet provides a virtual connection for remote access19 What are two characteristics of peer-to-peer networks? (Choose two.) scalableone way data flowdecentralized resourcescentralized user accountsresource sharing without a dedicated server20 What application layer protocol is commonly used to support for file transfers between a client and a server?HTMLHTTPFTPTelnetC42. With TCP/IP data encapsulation, which range of port numbers identifies all well-known applications?0 to 255256 to 10220 to 10231024 to 204749153 to 655353. Why are port numbers included in the TCP header of a segment?to indicate the correct router interface that should be used to forward a segmentto identify which switch ports should receive or forward the segmentto determine which Layer 3 protocol should be used to encapsulate the datato enable a receiving host to forward the data to the appropriate applicationto allow the receiving host to assemble the packet in the proper order4. Which OSI model layer is responsible for regulating the flow of information from source to destination, reliably and accurately?applicationpresentationsessiontransportnetwork6. Why is flow control used for TCP data transfer?to synchronize equipment speed for sent datato synchronize and order sequence numbers so data is sent in complete numerical orderto prevent the receiver from being overwhelmed by incoming datato synchronize window size on the serverto simplify data transfer to multiple hosts7. Which two options represent Layer 4 addressing? (Choose two.)identifies the destination networkidentifies source and destination hostsidentifies the communicating applicationsidentifies multiple conversations between the hostsidentifies the devices communicating over the local media10. What is dynamically selected by the source host when forwarding data? destination logical addresssource physical addressdefault gateway addresssource port11. What are two features of the User Datagram Protocol (UDP)? (Choose two.) flow controllow overheadconnectionlessconnection-orientedsequence and acknowledgements12. What mechanism is used by TCP to provide flow control as segments travel from source to destination?sequence numberssession establishmentwindow sizeacknowledgments13. Which transport layer protocol provides low overhead and would be used for applications which do not require reliable data delivery?TCPIPUDPHTTPDNS14. Which information is found in both the TCP and UDP header information? sequencingflow controlacknowledgmentssource and destination port15. Which three features allow TCP to reliably and accurately track the transmission of data from source to destination? (Choose three.)flow controlurgent pointerbest effort deliverysession establishmentconnectionless servicesnumbering and sequencing16. During a TCP communication session, if the packets arrive to the destination out of order, what will happen to the original message?The packets will not be delivered.The packets will be retransmitted from the source.The packets will be delivered and reassembled at the destination.The packets will be delivered and not reassembled at the destination.17. Which is an important characteristic of UDP?acknowledgement of data deliveryminimal delays in data deliveryhigh reliability of data deliverysame order data delivery18. After a web browser makes a request to a web server that is listening to the standard port, what will be the source port number in the TCP header of the response from the server?1353801024172819. Which event occurs during the transport layer three-way handshake?The two applications exchange data.TCP initializes the sequence numbers for the sessions.UDP establishes the maximum number of bytes to be sent.The server acknowledges the bytes of data received from the client.C51 What is the purpose of a default gateway?physically connects a computer to a networkprovides a permanent address to a computeridentifies the network to which a computer is connectedidentifies the logical address of a networked computer and uniquely identifies it to the rest of the networkidentifies the device that allows local network computers to communicate with devices on other networks2 What type of routing uses information that is manually entered into the routing table?dynamicinteriorstaticstandard4 Which IP packet field will prevent endless loops?type-of-serviceidentificationflagstime-to-liveheader checksum6 What is a component of a routing table entry?the MAC address of the interface of the routerthe destination Layer 4 port numberthe destination host addressthe next-hop address7 In an IPv4 environment, what information is used by the router to forward data packets from one interface of a router to another?destination network addresssource network addresssource MAC addresswell known port destination address8 What information is added during encapsulation at OSI Layer 3?source and destination MACsource and destination application protocolsource and destination port numbersource and destination IP address9 If the default gateway is configured incorrectly on the host, what is the impact on communications?The host is unable to communicate on the local network.The host can communicate with other hosts on the local network, but is unable to communicate with hosts on remote networks.The host can communicate with other hosts on remote networks, but is unable to communicate with hosts on the local network.There is no impact on communications.10 In a connectionless system, which of the following is correct?The destination is contacted before a packet is sent.The destination is not contacted before a packet is sent.The destination sends an acknowledgement to the source that indicates the packet was received.The destination sends an acknowledgement to the source that requests the next packet to be sent.11 Which portion of the network layer address does a router use to forward packets? host portionbroadcast addressnetwork portiongateway address13 When the destination network is not listed in the routing table of a Cisco router, what are two possible actions that the router might take? (Choose two.)The router sends an ARP request to determine the required next hop address.The router discards the packet.The router forwards the packet toward the next hop indicated in the ARP table.The router forwards the packet to the interface indicated by the source address.The router forwards the packet out the interface indicated by the default route entry.14 What are three common problems with a large network? (Choose three.)too few broadcastsperformance degradationsecurity issueslimited management responsibilityhost identificationprotocol compatibility15 Which three statements are true about routes and their use? (Choose three.)If no route to the destination network is found, the packet is returned to the previous router.If the destination network is directly connected, the router forwards the packet to the destination host.If multiple network entries exist for the destination network, the most general route is used to forward the packet.If no route exists for the destination network and a default route is present, the packet is forwarded to the next-hop router.If the originating host has a default gateway configured, the packet for a remote network can be forwarded using that route.If a host does not have a route manually configured for the destination network, the host will drop the packet.16 Which intermediary devices could be used to implement security between networks? (Choose two.)routerhubswitchfirewallaccess pointbridge19 What are the key factors to consider when grouping hosts into a common network? (Choose three.)gatewayspurposephysical addressingsoftware versiongeographic locationownership20 What two characteristics are commonly associated with dynamic routing protocols? (Choose two.)require no device configurationprovide routers with up-to-date routing tablesrequire less processing power than static routes requireconsume bandwidth to exchange route informationprevent manual configuration and maintenance of the routing table21. What statement describes the purpose of a default route?A host uses a default route to transfer data to another host on the same network segment.A host uses a default route to forward data to the local switch as the next hop to all destinations.A host uses a default route to identify the Layer 2 address of an end device on the local network.A host uses a default route to transfer data to a host outside the local network when no other route to the destination exists.C62 Which IPv4 subnetted addresses represent valid host addresses? (Choose three.) 172.16.4.127 /26172.16.4.155 /26172.16.4.193 /26172.16.4.95 /27172.16.4.159 /27172.16.4.207 /273 Which statements are true regarding IP addressing? (Choose two.)NAT translates public addresses to private addresses destined for the Internet.Only one company is allowed to use a specific private network address space.Private addresses are blocked from public Internet by router.Network 172.32.0.0 is part of the private address space.IP address 127.0.0.1 can be used for a host to direct traffic to itself.4 Which process do routers use to determine the subnet network address based upon a given IP address and subnet mask?binary addinghexadecimal andingbinary divisionbinary multiplicationbinary ANDing5 What is the network address of the host 172.25.67.99 /23 in binary?10101100. 00011001.01000011.0000000010101100. 00011001.01000011.1111111110101100. 00011001.01000010.0000000010101100. 00011001.01000010.0110001110101100. 00010001.01000011. 0110001010101100. 00011001.00000000.000000006 What subnet mask would a network administrator assign to a network address of 172.30.1.0 if it were possible to have up to 254 hosts?255.255.0.0255.255.255.0255.255.254.0255.255.248.07 Which three IP addresses are private? (Choose three.)172.168.33.110.35.66.70192.168.99.5172.18.88.90192.33.55.89172.35.16.58 Given the IP address and subnet mask of 172.16.134.64 255.255.255.224, which of the following would describe this address?This is a useable host address.This is a broadcast address.This is a network address.This is not a valid address.11 Which of the following network devices are recommended to be assigned static IP addresses? (Choose three.)LAN workstationsserversnetwork printersroutersremote workstationslaptops12 Which of the following are features of IPv6? (Choose three.)larger address spacefaster routing protocolsdata types and classes of serviceauthentication and encryptionimproved host naming conventionssame addressing scheme as IPv413 A router interface has been assigned an IP address of 172.16.192.166 with a mask of 255.255.255.248. To which subnet does the IP address belong?172.16.0.0172.16.192.0172.16.192.128172.16.192.160172.16.192.168172.16.192.17614 What two things will happen if a router receives an ICMP packet which has a TTL value of 1 and the destination host is several hops away? (Choose two.)The router will discard the packet.The router will decrement the TTL value and forward the packet to the next router on the path to the destination host.The router will send a time exceeded message to the source host.The router will increment the TTL value and forward the packet to the next router on the path to the destination host.The router will send an ICMP Redirect Message to the source host.16 How many bits make up an IPv4 address?12864483217 What is the primary reason for development of IPv6?securityheader format simplificationexpanded addressing capabilitiesaddressing simplification18 What three facts are true about the network portion of an IPv4 address? (Choose three.)identifies an individual deviceis identical for all hosts in a broadcast domainis altered as packet is forwardedvaries in lengthis used to forward packetsuses flat addressing19 What is a group of hosts called that have identical bit patterns in the high order bits of their addresses?an interneta networkan octeta radixC71 What is a function of the data link layer?。

2016CCNA1各章及期末考试答案

ITN 第7 章考试1什么是套接字？正确响应您的响应源和目的IP 地址以及源和目的以太网地址的组合源IP 地址与端口号的组合或目的IP 地址与端口号的组合源和目的序列号和确认号的组合源和目的序列号和端口号的组合套接字是源IP 地址与源端口号的组合，或者目的IP 地址与目的端口号的组合。

此试题参考以下领域的内容：Introduction to Networks•7.1.2 TCP 和UDP 简介2主机设备需要通过网络发送大型视频文件，同时为其他用户提供数据通信。

下列哪种功能可以让不同通信流同时发生，而不会让一个数据流使用所有可用带宽？正确响应您的响应窗口大小多路复用端口号确认多路复用对交替发送多个通信流很有用。

窗口大小用于降低数据通信速率。

端口号用于将数据流传送到正确的应用程序。

确认用于通知发送设备数据包流已收到或未收到。

此试题参考以下领域的内容：Introduction to Networks•7.1.1 数据传输3主机设备通过HTTP 协议向Web 服务器发送数据包。

传输层使用下列哪项来将数据流传送到服务器上的正确应用程序？正确响应您的响应序列号确认源端口号目的端口号目的端口号用于将数据流传输到正确的应用程序，而源端口号由源设备随机生成并进行跟踪。

序列号用于指示如何重组和重新排序收到的数据段。

确认用于通知发送设备数据包流已收到或未收到。

此试题参考以下领域的内容：Introduction to Networks•7.1.1 数据传输4UDP 传输协议有什么有利功能？正确响应您的响应确认已接收的数据减少传输延迟使用序列号跟踪数据段能够重新传输丢失的数据由于其报头小于TCP 报头，UDP 协议可以减少传输延迟。

此试题参考以下领域的内容：Introduction to Networks•7.1.1 数据传输5下列哪种场景描述了传输层提供的功能？正确响应您的响应学生使用教室里的VoIP 电话给家里打电话。

ccna1章节与期末答案

第一章：正确答案：2.4.5•解析：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正确答案：1解析：正确答案： 3.5解析：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。

正确答案：3和4解析：终端设备上的应用程序可以生成数据，更改数据内容并且负责启动封装过程。

正确答案：1和4解析：终端设备会发出通过网络传输的数据。

中间设备会在链路发生故障时通过备用路径传输数据，并且会过滤数据传输以增强安全性。

网络介质提供网络消息的传输通道。

正确答案：4解析：外联网是公司外部的人或企业合作伙伴访问数据的网络区域。

内部网只描述通常仅供内部人员访问的网络区域。

当设备连接到有线网络时，有线LAN 会受BYOD（自带设备）影响。

使用大学无线LAN 的设备多为平板电脑和智能手机。

大学生主要使用无线WAN 来访问他们的手机运营商网络。

.正确答案：2解析：由于通过Internet 可以联系在线供应商，所以家庭用户通过Internet 进行网上购物。

内联网基本上是仅供内部使用的局域网。

外联网是外部合作伙伴访问组织内部特定资源的网络。

家庭用户并不一定使用LAN 来访问Internet。

例如，PC 可以通过调制解调器直接连接到ISP。

正确答案：1解析：内部网这个术语用于表示一个组织的私有局域网和广域网连接。

内部网的设计旨在仅允许该组织的成员、员工或其他获得授权的人员进行访问。

正确答案：2和4解析：电缆和DSL 均能实现高带宽、始终联网，并提供到主机计算机或LAN 的以太网连接。

10正确答案：2和3解析：移动电话连接需要使用移动电话网络。

卫星连接通常用于家庭或企业外部不便使用物理布线的位置。

11正确答案：2解析：当对网络资源的请求超出了可用容量时，网络就会变得拥堵。

CCNA1全书练习题（所有章节chapter1至11）

CCNA1全书练习题（所有章节chapter1⾄11）CCNA Exploration: ⽹络基础知识 (版本 4.0)第2章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D. 详细规定构成物理链路的组件及其接⼊⽅法E. 将数据段划分为数据包2．在封装过程中，数据链路层执⾏什么操作？A. 不添加地址。

B. 添加逻辑地址。

C. 添加物理地址。

D. 添加进程的端⼝号。

3. 请参见图⽰。

下列哪组设备仅包含终端设备？A. A、C、DB. B、E、G、HC. C、D、G、H、I、JD. D、E、F、H、I、JE. E、F、H、I、J4. 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）A. 确定数据传输路径B. 发起数据通信C. 重新定时和重新传输数据信号D. 发送数据流E. 管理数据流F. 数据流最后的终⽌点5. 下列哪三项陈述是对局域⽹ (LAN) 最准确的描述？（选择三项）A. LAN 通常位于⼀个地域内。

B. 此类⽹络由由⼀个组织管理。

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。

E. LAN 为同⼀个组织内的⽤户提供⽹络服务和应⽤程序访问。

F. 此类⽹络的每个终端通常都连接到电信服务提供商 (TSP)。

6. 通过检查⽹络层报头可以确定什么？A. 本地介质上的⽬的设备B. ⽤于到达⽬的主机的路径C. 将要通过介质传输的⽐特D. 创建数据的源应⽤程序或进程7. 哪种设备被视为中间设备？A. ⽂件服务器B. IP 电话C. 笔记本电脑D. 打印机E. 交换机8. OSI 模型各层从最⾼层到最低层的正确顺序如何？A. 物理层、⽹络层、应⽤层、数据链路层、表⽰层、会话层、传输层B. 应⽤层、物理层、会话层、传输层、⽹络层、数据链路层、表⽰层C. 应⽤层、表⽰层、物理层、会话层、数据链路层、传输层、⽹络层D. 应⽤层、表⽰层、会话层、传输层、⽹络层、数据链路层、物理层E. 表⽰层、数据链路层、会话层、传输层、⽹络层、物理层、应⽤层9. 请参见图⽰。

CCNA第一学期各章习题和参考答案.doc

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。

CCNA第一学期各章知识题及答案解析

诶了我累了目录第二章网络通信P2-8第三章应用层功能及协议P9-14 第四章OSI传输层P15-20第五章OSI网络层P21-27第六章网络编址-IPv4 P28-34第七章数据链路层P35-40第八章OSI物理层P41-45第九章以太网P46-51第十章网络规划和布线P52-61 第十一章配置和测试网络P62-70 第一学期末考试P71-91文档末尾返回目录第二章网络通信001 TCP/IP 网络接入层有何作用？路径确定和数据包交换数据表示、编码和控制可靠性、流量控制和错误检测详细规定构成物理链路的组件及其接入方法将数据段划分为数据包002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）确定数据传输路径发起数据通信重新定时和重新传输数据信号发送数据流管理数据流数据流最后的终止点003下列哪三项陈述是对局域网(LAN) 最准确的描述？（选择三项）LAN 通常位于一个地域内。

此类网络由由一个组织管理。

LAN 中的不同网段之间一般通过租用连接的方式连接。

此类网络的安全和访问控制由服务提供商控制。

LAN 为同一个组织内的用户提供网络服务和应用程序访问。

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？传输期间的帧损坏在目的设备上重组的数据因通信丢失而重新传输的数据包特定层的封装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）网络层传输层物理层数据链路层会话层006请参见图示。

所示网络属于哪一类型？WANMANLANWLAN007 以下哪种特征正确代表了网络中的终端设备？管理数据流发送数据流重新定时和重新传输数据信号确定数据传输路径008 第4 层端口指定的主要作用是什么？标识本地介质中的设备标识源设备和目的设备之间的跳数向中间设备标识通过该网络的最佳路径标识正在通信的源终端设备和目的终端设备标识终端设备内正在通信的进程或服务009 请参见图示。

CCNA十一章答案

思科c c n a第11章测试1此试题参考以下领域的内容：Introduction to Networks•11.1.1 小型网络中的设备2 哪种协议支持流媒体的快正确响应您的响应SNMPTCPPoERTPSNMP 是一种管理协议。

TCP 不适而是允许以太网电缆为设备输送电源此试题参考以下领域的内容：Introduction to Networks•11.1.2 小型网络中的协议3 如何捕获流量才能更好地了解网络中的流量模式？正确响应您的响应在利用率较低时在利用率高峰期当流量仅在主干网段上当流量来自用户子集时在利用率较低时捕获流量无法获得不同流量类型的正确表示。

由于某些流量可能局限于特定网捕获流量。

此试题参考以下领域的内容：Introduction to Networks•11.1.3 发展为大型网络4 网络管理员检查安全日志，发现周末有人未经授权访问了一个器。

经过仔细调查文件系统日志，管理员注意到几个重要文档部的主机。

这种情况代表哪种威胁？正确响应您的响应数据丢失身份盗窃信息盗窃服务中断信息盗窃威胁是指公司的内部信息被未授权的用户访问和复制。

此试题参考以下领域的内容：Introduction to Networks•11.2.1 网络设备安全措施5 下列哪两项操作可以防止他人成功攻击电子邮件服务器帐户？（正确响应您的响应不要通过网络以明文形式发送密码。

不要使用需要Shift 键的密码。

不要允许服务器控制台的物理访问。

仅允许授权人员访问服务器机房。

限制登录到服务器的失败尝试次数。

最常见的一种访问攻击类型是利用数据包嗅探器来获取以明文形式传输的用户帐户和密码。

反进行未经授权的访问，属于另一种访问攻击。

限制尝试登录到服务器的次数并使用加密密码，攻击类型成功登录。

此试题参考以下领域的内容：Introduction to Networks•11.2.2 漏洞和网络攻击6 下列哪种网络攻击会导致网络、系统或服务的禁用或损坏？正确响应您的响应侦察攻击访问攻击拒绝服务攻击恶意代码攻击拒绝服务攻击是指网络、系统或服务被禁用或损坏。

ccna第一章练习答案

1．Several computers in the company require new NICs. A technician has located a good price on the Internet for the purchase of these NICs. Before these NICs are purchased and installed, what details must be verified? (Choose three.)the MAC address on the NICthe size of the RAM on the NICthe bandwidth supported by the NICthe type of media supported by the NICthe type of network architecture supported by the NIC2. What are three conditions that would require a network administrator to install a new NIC? (Choose three.)whenever a NIC is damagedwhen there is a need to provide a secondary or backup NICwhen there is a change from copper media to wirelesswhenever operating system security patches are appliedwhenever the PC has been moved to a different location3. What is the hexadecimal equivalent for the binary number 10001110?2267142AE8E4. Represented as a decimal number, what is the result of the logical ANDing of binary numbers 00100011 and 11111100?332352202555. What is the binary equivalent for the decimal number 248?111000001111000011110100111110006. Convert the binary number 01011011 into its hexadecimal equivalent. Select the correct answer from the list below.5A5B5C5D6B7A7. What is the binary equivalent for decimal number 149?1001011110010101100110011001011110101011101011018. What is the binary equivalent for the decimal number 162?10100010101001001010110110110000101011009. Which device connects a computer with a telephone line by providing modulation and demodulation of incoming and outgoing data?NICCSU/DSUroutermodemtelco switch10. Convert the Base 10 number 116 into its eight bit binary equivalent. Choose the correct answer from the following list:01111010011100100111010001110110011101110101011011. Which specialized equipment is used to make a physical connection from a PC to a network?routerRAMnetwork interface card12. Which phrases describe a byte? (Choose two.)a single binary digit+5 volts of electricitythe value range 0 to 127a grouping of eight binary digitsa single addressable data storage location13. What is the hexadecimal equivalent for the binary number 00100101?15202530374014. In an 8 bit binary number, what is the total number of combinations of the eight bits?128254255256512102415. Which of the following are popular web browsers? (Choose two.)AcrobatInternet ExplorerMacromedia FlashNetscape NavigatorQuicktimeWorld Wide Web16. Convert the decimal number 231 into its binary equivalent. Select the correct answer from the list below.111100101101101111110110111001111110010111101110。

ccna第二章章节习题加答案

第1章路由和数据包转发介绍1.下面哪些路由器的组成和它的功能是匹配的？DA.Flash：永久的储存bootstrap程序B.ROM：永久地存储启动配置文件C.NVRAM：永久地存储操作系统镜像D.RAM：存储路由表和ARP缓存2.哪两个命令可以用来检查给路由器串行接口分配的IP地址？A、EA.show interfacesB.show interfaces ip briefC.show controllers allD.show ip configE.show ip interface brief3.下面哪些命令可以设置特权模式口令为“quiz”？AA.R1（config）# enable secret quizB.R1（config）# password secret quizC.R1（config）# enable password secret quizD.R1（config）# enable secret password quiz4.哪个路由原理是正确的？CA.如果一个路由器在它的路由表中具有确定的信息，那么所有邻接的路由也拥有同样的信息B.从一个网络到另外一个网络路径的路由信息意味着存在着反向（或返回）路径的路由信息C.每个路由器根据它自己路由表中的信息，独立作出路由判断D.每个路由器根据它自己和邻居路由表中的信息，独立作出路由判断5.动态路由协议执行哪两个任务？B、DA.发现主机B.更新和维护路由表C.传播主机默认网关D.网络发现E.分配IP地址6.网络工程师正在配置一个新的路由器。

接口已经配置好了IP地址，并且已经激活。

但是还没有配置路由协议或静态路由。

这时路由表中出现的是什么路由？CA.默认路由B.广播路由C.直接路由D.没有路由，路由表也是空的7.下面哪两个对于路由器转发数据包的描述是正确的？B、DA.如果数据包是去往远程网络的，那么路由器会向所有到这个网络的下一跳接口发送该数据包B.如果数据包是去往直连网络的，那么路由器会向路由表中所指示的外出接口发送C.如果数据包是去往远程网络的，那么路由器会根据路由主机表来发送该数据包D.如果数据包是去往远程网络的，那么路由器会向路由表中所指示下一跳IP发送E.如果数据包是去往直连网络的，那么路由器会根据目的MAC地址发送该数据包F.如果数据包是去往直连网络的，那么路由器会转发数据包到下一跳VLAN的交换机8.关于路由协议使用的度量的哪个描述是正确的？AA.度量是路由协议用来检测给定路由的一个测量值B.度量是思科专有的用来转换距离到标准单元的方法C.度量表示了对于所有路由协议中发生的数据包丢失的数量的一个统计值D.路由器使用度量lai 决定哪些包是错误的和要被丢失的9.网络管理员在路由器上配置了ip rout 0.0.0.0 0.0.0.0 serial 0/0/0命令。

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第二章1.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）答案：1，确定数据传输路径3，重新定时和重新传输数据信号5，管理数据流2.请选择关于网络协议的正确陈述（选择三项）答案：1，定义特定层PDU的结构3，概述层与层之间通信所需的功能5，需要取决于协议层的封装过程3.封装的两个功能是什么？（选择两项）答案：4，标识属于同一通信的数据片段5，确保数据片段可以转发到正确的接收端设备4.数据链路层封装添加的报尾信息有何主要功能？答案：1，支持差错校验5.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）答案：3，物理层4，数据链路层6.什么是PDU？答案：4，特定层的封装7.以下哪种特征正确代表了网络中的终端设备？答案：2，发送数据流8.请参见图示。

IP地址为10.0.0.34的“手机A”已经与IP地址为172.16.1.103的“IP电话1”建立了IP会话。

请根据图示回答，下列哪个设备类型是对无线设备“手机A”功能的最准确描述？答案：2，终端设备9.请参见图示。

下列哪三个标签正确标识了图示网段的网络类型？（选择三项）答案：2，网络B—WAN 3,网络C—LAN 6，网络A—LAN10.下列哪三项陈述是对局域网（LAN）最准确的描述？（选择三项）答案：1，LAN通常位于一个地域内2，此类网络由一个组织管理5，LAN为同一个组织内的用户提供网络服务和应用程序访问11.请参见图示。

哪个网络术语描述了图中所示的数据交替发送过程？答案：4，多路复用12.第4层端口指定的主要作用是什么？答案：5，标识终端设备内正在通信的进程或服务13.哪种设备被视为中间设备？答案：5，交换机14.请参见图示。

哪个术语正确判断出了包含于区域B中的设备类型？答案：4，中间设备15.请参见图示。

所示网络属于哪一类型？答案：3，LAN16.哪一层负责将数据段封装成数据包？答案：3，网络层17.通过检查网络层头部可以确定什么？答案：2，目的主机地址18.请参见图示。

下列哪组设备仅包含终端设备？答案：5，E、F、H、I、J19.在封装过程中，数据链路层执行什么操作？答案：3，添加物理地址。

20.TCP/IP网络接入层有何作用？答案：4，网络介质控制21.OSI模型各层从最高层到最低层的正确顺序如何？答案：4，应用层、表示层、会话层、传输层、网络层、数据链路层、物理层第三章1.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？答案：3，FTP2.应用层软件的两种形式是什么？（选择两项）答案：1，应用程序4，服务3.资源记录在DNS中有何作用？答案：2，服务器用其解析域名4.网络管理员正在为拥有二十五名用户的新分公司设计网络。

使用客户端—服务器模型有哪些优势？（选择两项）答案：1，集中管理3，更易于执行安全管理5.以下哪三种协议在OSI模型的应用层中工作？（选择三项）答案：2，DNS 4，SMTP 5，POP6.将资源名称与所需IP地址匹配的自动化服务是什么？答案：4，DNS7.以下哪三项是点对点应用程序的属性？（选择三项）答案：1，在同一次通信中既是客户端也是服务器3，采用混合模式，使用一个中央文件目录4，可以在客户端服务器网络中使用8.以下哪些应用层协议正确匹配了相应的功能？（选择两项）答案：2，HTTP从Web服务器向客户端传输数据5，Telnet提供远程访问的虚拟连接9.哪些电子邮件组件用于在服务器之间转发邮件？（选择两项）答案：3，MTA 5，SMTP10.与SSH相比，telnet的主要缺点是什么？答案：2，不支持加密11.关于MTA在处理电子邮件中的作用，下列哪些陈述是正确的？（选择三项）答案：2，从客户端的MUA接收电子邮件4，将电子邮件传送到MDA供最终分发5，使用SMTP在服务器之间路由电子邮件12.哪两项协议用于控制从Web服务器向客户端浏览器传输Web资源？（选择两项）答案：4，HTTP 5，HTTPS13.为了将三台计算机连接到一起进行游戏和文件共享，已经安装了一个小型家庭网络。

以下哪两种属性代表此网络类型？（选择两项）答案：2，难以执行安全管理。

5，响应文件共享请求的计算机发挥服务器的作用14.OSI模型哪一层提供的服务让用户可以连接到网络？答案：5，应用层15.请参见图示。

第5行中所示通信的目的端口是多少？答案：1，8016.以下哪两项是点对点网络的特征？（选择两项）答案：3，分散资源5，共享资源时可以不借助专用服务器17.哪个应用层协议中规定了Microsoft网络中用于文件共享的服务？答案：3，SMB18.数据网络中的客户端有哪两种特征？（选择两项）答案：2，发起数据交换4，可以向服务器上传数据19.OSI应用层有何作用？答案：3，提供网络任意终端上应用程序之间的接口20.服务器上的应用层通常如何处理多客户端服务请求？答案：4，使用下一层功能的支持来区分不同的服务连接第四章1.根据图中所示的传输层报头回答，以下哪些陈述了建立的会话？（选择两项）答案：2，包含Telnet请求5，这是TCP报头2.采用TCP/IP数据封装时，以下哪个端口号范围标识了所有常用应用程序？答案：3，0到10233.请参见图示。

主机A正在使用FTP从服务器1下载大型文件。

在下载期间，服务器1没有收到主机A对若干字节传输数据的确认。

服务器1将默认执行什么操作？答案：2，到达超时时间后重新发送需要确认的数据4.数据段的TCP报头中为什么包含端口号？答案：4，让接收主机转发数据到适当的应用程序5.将流量控制用于TCP数据传输的原因是什么？答案：3，防止传入数据耗尽接收方资源6.OSI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？答案：4，传输层7.以下哪两个选项代表第4层编址？（选择两项）答案：3，标识正在通信的应用程序4，标识主机之间的多个会话8.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？答案：1，会话创建9.请参见图示。

从显示的输出中可以确定以下哪两项信息？（选择两项）答案：1，本地主机正在使用三个客户端会话。

2，本地主机正在使用到远程服务器的Web 会话。

10．下列哪项由源主机在转发数据时动态选择？答案：4，源端口11.下列哪两项是用户数据报协议（UDP）的功能？（选择两项）答案：2，系统开销低3，无连接12.从源向目的传送数据段的过程中，TCP使用什么机制提供流量控制？答案：3，窗口大小13.TCP报头信息和UDP报头信息中都包含下列哪项信息？答案：4，源端口和目的端口14.下列哪三项功能使TCP得以准确可靠地跟踪从源设备到目的设备的数据传输？（选择三项）答案：1，流量控制4，会话创建6，编号和定序15.在TCP通信会话期间，如果数据包到达目的主机的顺序混乱，将对原始消息执行什么操作？答案：3，数据包将送达目的主机并重组16.下列哪个传输层协议提供低开销传输因而可用于不需要可靠数据传输的应用场合？答案：3，UDP17.下列哪项是UDP的重要特征？答案：2，数据传输的延迟最短18.Web 浏览器向侦听标准端口的Web服务器发出请求之后，在服务器响应的TCP报头中，源端口号是多少？答案：3，8019.以下哪个事件发生于传输层三次握手期间？答案：2，TCP初始化会话的序列号20.请参见图示。

Host1正在与Host2建立TCP会话。

Host1已经发送了SYN信息，开始建立会话。

接下来会发生什么？答案：Host1会向Host2发送带有ACK标志＝1、SYN标志＝0的数据段第五章1.在IPv4环境中，路由器根据什么信息在不同的路由器接口之间转发数据包？答案：1，目的网络地址2.OSI第3层封装期间添加什么信息？答案：4，源IP地址和目的IP地址3.在无连接系统中，下列哪项陈述是正确的？答案：2，发送数据包之前不联系目的设备4.IP数据包的哪个字段用于防止无限循环？答案：4，生存时间5.路由器使用网络层地址的哪个部分转发数据包？答案：3，网络部分6.请参见图示。

如果使用图示中的网络，下列哪一项将成为192.133.219.0 网络中主机A的默认网关地址?答案：4,192.133.219.17.如果主机上的默认网关配置不正确,对通信有何影响?答案：2,该主机可以与本地网络中的其它主机通信,但不能与远程网络上的主机通信. 8.默认网关有何作用？答案：5，允许本地网络计算机和其它网络中的设备通信的设备标识9.哪种路由使用的信息需要手动输入路由表中？答案：3，静态10．如果目的网络未列在Cisco路由器的路由表中，路由器可能会采取哪两项措施？（选择两项）答案：2，路由器丢弃数据包5，路由器将数据包从默认路由条目所确定的接口发出11.将主机分组到同一个网络时应考虑哪些关键因素？（选择三项）答案：2，用途5，地理位置6，所有权12.以下哪一项是路由表条目的组成部分？答案：4，下一跳地址13.下列哪些中间设备可用于网络之间实施安全保护？（选择两项）答案：1，路由器4，防火墙14.大型网络存在哪三个常见问题？（选择三项）答案：2，性能下降3，安全问题5，主机标识15.请参见图示。

图中显示的所有设备均为出厂默认设置。

图示拓扑代表多少个广播域？答案：2，416.下列关于路由及其用途的陈述，哪三项是正确的？（选择三项）答案：2，如果目的网络直接连接的网络，路由器会将数据包转发到目的主机。

4，如果不存在代表目的网络的路由但存在默认路由，则将数据包转发到下一跳路由器。

5，如果发送主机配置了默认网关，可以使用该路由转发以远程网络为目的网络的数据包17.请参见图示。

网络管理员正在排除连接故障，需要确定用于向网络外转发网络数据包的地址。

管理员netstat-r命令确定该地址时,会发现所有主机将发往外部网络的数据包发送到以下哪个地址?答案：3,10.10.10.618.请参见图示。

网络管理员发现网络中存在过多广播。

网络管理员采取哪两个步骤可以解决此问题？（选择两项）答案：19.请参见图示。

图中网络的运行完全正常。

下列哪两项陈述正确描述了所示拓扑的路由？（选择两项）答案：1，R3使用192.168.0.2 作为下一跳地址将数据包从10.0.0.0网络路由到172.16.0.0网络5,R2使用192.168.0.1 作为下一跳地址将数据包从172.16.0.0网络路由到192.168.12.0网络20.下列哪两项特征通常与动态路由协议相关？（选择两项）答案：2，为路由器提供最新的路由表4，交换路由信息需要消耗带宽21.下列哪项陈述描述了默认路由的作用？答案：4，不存在通往目的主机的其它路由时，主机使用默认路由将数据传输到本地网络外的主机。

第六章1、下列哪个网络前缀将使用图中显示的IP编址方答案：4：/272、下列哪些划分子网后的IPV4地址代表有效的主机地址（选择三项）答案：2：172.16.4.155/26 3：172.16.4.193/26 6 ：172.16.4.207/273、下列关于IP编址的陈述，哪些是正确的？答案：3：路由器阻止私有地址接入公共INTERNET 5：主机可以使用IP地址127.0.0.1向自身发送通信。