CCNA第二学期测试_第十章答案
CCNA 2 Chapter 10 V4.0 Answers
1. What action does a link-state router take immediately upon receipt of an LSP from a neighboring router?floods the LSP to neighborscalculates the SPF algorithmruns the Bellman-Ford algorithmcomputes the best path to the destination network2. Why is it difficult for routing loops to occur in networks that use link-state routing?Each router builds a simple view of the network based on hop count. Routers flood the network with LSAs to discover routing loops.Each router builds a complete and synchronized view of the network. Routers use hold-down timers to prevent routing loops.3.Refer to the exhibit. What kind of information would be seen in an LSP sent from router JAX to router ATL?hop countuptime of the routecost of the linka list of all the routing protocols in use4. To achieve network convergence, what three steps does each link state router take? (Choose three.)use automatic summarization to reduce the size of routing tablesbuild a Link State Packet (LSP) containing the state of each directly connected linkflood the LSP to all neighbors, who then store all LSPs received in a databasediscover neighbors and establish adjacencies using the hello packet sent at regular intervalsconstruct a complete map of the topology and compute the best path to each destination networkuse the DUAL FSM to select efficient, loop-free paths, and insert routes into the routing table5.Refer to the exhibit. When Router D is configured to use a link-state routing protocol and is added to the network, what is the first thing that it does to begin learning the network topology?It sends LSP packets to Routers B and C.It sends LSP packets to all routers in the network.It sends Hello packets to all routers in the network.It sends information about its directly connected neighbors to Routers A and E.It sends information about its directly connected neighbors to all routers in the network.It learns about its directly connected networks when its interfaces reach the up state.6. A new network administrator is given the task of selecting an appropriate dynamic routing protocol for a software development company. The company has over 100 routers, uses CIDR and VLSM, requires fast convergence, and uses both Cisco and non-Cisco equipment. Which routing protocol is appropriate for this company?RIP version 2IGRPEIGRPOSPFBGP7. What two events will cause a link state router to send LSPs to all neighbors? (Choose two.)30 second timer expireswhenever the network topology changesimmediately after the Bellman-Ford algorithm has runimmediately after the DUAL FSM has built the topology databaseupon initial startup of router or routing protocol8. What is the final step in the link state routing process? successors are placed into the routing tableSPF computes best path to each destination networkLSPs are flooded to all neighbors to converge the networkDUAL algorithm is run to find best path to destination networks9.Refer to the exhibit. What does JAX do with link-state packets from ORL? sends out its updated routing table to both ORL and BOS routerssends out the individual link-state packets out the interface connected to BOSqueries BOS to see if it has a better routeonly adds it to the local routing table and performs no other actions10. What two statements correctly describe the link state routing process? (Choose two.)each router in the area floods LSPs to all neighborsall routers in the area have identical link state databasesLSPs use the reserved multicast address of 224.0.0.10 to reach neighbors routing loops are prevented by running the Diffusing Update Algorithm (DUAL)Reliable Transport Protocol (RTP) is the protocol used by for the delivery and reception of LSPs11. Which database or table must be identical on all link-state routers within an area in order to construct an accurate SPF tree?routing tableadjacency tablelink-state databaseneighbor tabletopology database12.Refer to the exhibit. Which statement correctly describes the path traffic would take from the 10.0.0.0/24 network to the 192.168.1.0/24 network if a link-state routing protocol was in use?BOS -> ATL because this path is the least hopsBOS -> ATL because this path is highest costBOS -> ORL -> JAX -> ATL because this path is the lowest costtraffic would load balance across all links13. What feature do modern link-state protocols provide to minimize processing and memory requirements?splitting routing topologies into smaller areasassigning lower process priorities to route calculationsusing update timers to restrict routing updatesstrict split horizon rules to reduce routing table entries14. What speeds up convergence in a network using link-state routing? updates triggered by network changesupdates sent at regular intervalsupdates sent only to directly connected neighborsupdates that include complete routing tables15. Which algorithm is run by link-state routing protocols to calculate the shortest path to destination networks?DUALDijkstraBellman-FordDiffie-Hellman16. What are some of the advantages of using a link-state routing protocol instead of a distance vector routing protocol? (Choose two.)The topology database eliminates the need for a routing table.Frequent periodic updates are sent to minimize the number of incorrect routes in the topological database.Routers have direct knowledge of all links in the network and how they are connected.After the inital LSA flooding, they generally require less bandwidth to communicate changes in a topology.Link-state protocols require less router processor power than distance vector protocols.17.Refer to the exhibit. If all routers and interfaces are configured to use a link-state routing protocol, from which routers will router D receive hello packets?A and EB and CA, B, C, and EC only18. Which two routing protocols use Dijkstra’s shortest path first algorithm? (Choose two.)RIPv1RIPv2IS-ISBGPEIGRPOSPF19. When are link-state packets sent to neighbors?every 30 secondsevery 180 secondsafter the holddown time expireswhen a link goes up or downwhen a routing loop occurs20. What are two advantages of using a link-state routing protocol instead of a distance vector routing protocol? (Choose two.)The topology database eliminates the need for a routing table.Each router independently determines the route to each network.Link-state protocols require less router processor power than distance vector protocols.After the inital LSP flooding, they generally require less bandwidth to communicate changes in a topology.Frequent periodic updates are sent to minimize the number of incorrect routes in the topological database.21. To achieve network convergence, what three steps does each link state router take? (Choose three.)use automatic summarization to reduce the size of routing tables build a Link State Packet (LSP) containing the state of each directly connected linkflood the LSP to all neighbors, who then store all LSPs received in a databasesend hello packages at regular intervals to discover neighbors and establish adjacenciesconstruct a complete map of the topology and compute the best path to each destination networkuse the DUAL FSM to select efficient, loop-free paths, and insert routes into the routing table。
完整版CCNA测试题库及答案
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。
CCNA认证基础课程-课后作业.习题答案
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。
CCNA认证试题(中文+答案)
CCNA认证试题一（附答案和解析）中文版(一）1、目前,我国应用最为广泛的LAN标准是基于(）的以太网标准.（A) IEEE 802。
1(B) IEEE 802。
2（C) IEEE 802.3（D）IEEE 802.5答案：C参考知识点：现有标准:IEEE 802.1 局域网协议高层IEEE 802.2 逻辑链路控制IEEE 802。
3 以太网IEEE 802.4 令牌总线IEEE 802。
5 令牌环IEEE 802.8 FDDIIEEE 802。
11 无线局域网记住IEEE802.1-——-—--IEEE802。
5的定义以太网是一种计算机局域网组网技术.IEEE制定的IEEE 802。
3标准给出了以太网的技术标准.它规定了包括物理层的连线、电信号和介质访问层协议的内容。
以太网是当前应用最普遍的局域网技术.它很大程度上取代了其他局域网标准,如令牌环、FDDI和ARCNET。
以太网的标准拓扑结构为总线型拓扑，但目前的快速以太网（100BASE—T、1000BASE-T标准）为了最大程度的减少冲突，最大程度的提高网络速度和使用效率，使用交换机（Switch）来进行网络连接和组织,这样，以太网的拓扑结构就成了星型，但在逻辑上，以太网仍然使用总线型拓扑的C**＊A/CD介质访问控制方法.电气电子工程师协会或IEEE（Institute of Electrical and Electronics Engineers）是一个国际性的电子技术与信息科学工程师的协会.建会于1963年1月1日。
总部在美国纽约市。
在150多个国家中它拥有300多个地方分会。
目前会员数是36万.专业上它有35个专业学会和两个联合会。
IEEE发表多种杂志,学报,书籍和每年组织300多次专业会议。
IEEE定义的标准在工业界有极大的影响.下面列出：IEEE802．3以太网标准802。
3--——---—— 10Base以太网标准802.3u-—------ 100Base-T（快速以太网）802.3z—-—————— 1000Base-X（光纤吉比特以太网）802.3ab———-——-— 1000Base—T（双绞线吉比特以太网）2、对于这样一个地址，192。
CCNA第二学期答案
.请参见图示。
对于发往的数据包，R2 会采取什么操作？它会丢弃数据包。
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 Fa0/1ip route4.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 时失败。
造成此问题的原因可能是什么？默认路由配置有误。
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。
）R2 的路由表中缺少的条目。
R1 的路由表中缺少的条目。
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？未在这两台路由器上配置路由协议。
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。
下列哪两项是该协议的特征？（选择两项。
使用贝尔曼-福特算法确定最佳路径。
定期将完整的路由表发送给所有连接的设备。
8.请参见图示。
两台路由器无法建立相邻关系。
此问题的原因可能是什么？这两台路由器上的hello 间隔和dead 间隔不同9.在两台路由器能够使用OSPF 形成邻居邻接关系之前必须完成哪两项任务？（选择两项。
）路由器必须在网络类型方面达成一致。
路由器必须使用相同的dead 时间间隔。
10.下列关于链路状态路由协议的陈述，哪两项是正确的？（选择两项。
）运行链路状态协议的路由器可以建立完整的网络拓扑使用最短路径优先算法。
11.请参见图示。
下列关于Router1 路由表的陈述，哪三项是正确的？（选择三项。
）EIGRP 路由的AD 已经手动更改为默认值以外的其它值。
Router1 正同时运行着EIGRP 和OSPF 路由过程尚未配置任何默认路由。
ccna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。
ccna第二学期练习答案中文
ERouting Chapter 1 - CCNA Exploration: 路由协议和概念(版本4.0)1口令可用于限制对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2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？第 2 层源地址和目的地址3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IP 地址。
从路由器ping 相连网络上的主机口之间相互ping 都会遭到失败。
此问题最可能的原因是什么？必须使用no shutdown命令启用接口。
4请参见图示。
主机 A ping 主机B。
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。
）目的IP 地址：192.168.10.134目的MAC 地址：9999.DADC.12345网络管理员刚把新配置输入Router1。
要将配置更改保存到NVRAM，应该执行哪一条命令？Router1# copy running-config startup-config6您需要配置图中所示的串行连接，必须在Sydney 路由器上发出以下哪条配置命令才能与Melbourne 站点建立连接？（选Sydney(config-if)# ip address 201.100.53.2 255.255.255.0Sydney(config-if)# no shutdownSydney(config-if)# clock rate 560007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请参见图示。
在主机 2 连接到LAN 上的交换机后，主机2 无法与主机 1 通信。
导致此问题的原因是什么？主机 1 和主机2 位于不同的网络中。
9输入以下命令的作用是什么？R1(config)# line vty 0 4R1(config-line)# password check123R1(config-line)# login设置通过Telnet 连接该路由器时使用的口令10以下哪一项正确描述了路由器启动时的顺序？加载bootstrap、加载IOS、应用配置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。
思科CCNA考试答案(全)
CCNA思科考试答案（全）第 1 章考试1一家拥有10 名员工的小型公司使用单个LAN 在计算机之间共享信息。
哪种类型连接适合此公司？由当地电话服务提供商提供的拨号连接能够使公司方便且安全地连接员工的虚拟专用网络通过当地服务提供商建立的私有专用线路通过当地服务提供商提供的宽带服务（如DSL）答案：4解析：对于这种小型办公室，比较适合通过被称为数字用户线路(DSL) 的常见宽带服务实现Internet 连接，这种服务由当地的电话服务提供商提供。
由于员工人数很少，带宽的问题并不突出。
如果公司较大，在远程站点有分支机构，则专用线路会更加适合。
如果公司员工需要通过Internet 与公司联系，则采用虚拟专用网。
2哪种网络情况需要使用WAN？员工工作站需要获取动态分配的IP 地址。
员工在出差时需要通过VPN 连接到公司电子邮件服务器。
分支机构的员工需要与同一园区网络上的另一座建筑物内的公司总部共享文件。
员工需要访问托管在其建筑物内DMZ 中的公司Web 服务器上的网页。
答案：2解析：当出差的员工需要通过WAN 连接到公司电子邮件服务器时，VPN 将通过WAN 连接在员工笔记本电脑与公司网络之间创建一个安全隧道。
通过DHCP 获取动态IP 地址是LAN 通信的功能。
在企业园区的不同建筑物之间共享文件可通过LAN 基础设施来实现。
DMZ 是企业LAN 基础设施内一个受保护的网络。
3以下哪项描述了WAN 的特征？WAN 和LAN 在同一地理范围内运行，但有串行链路。
WAN 网络归运营商所有。
所有串行链路均被视为WAN 连接。
WAN 可提供到园区主干网的终端用户网络连接。
答案：2解析：WAN 可用于将企业LAN 互连到远程分支机构站点LAN 和远程工作人员站点。
WAN 归运营商所有。
虽然WAN 连接一般通过串行接口实现，但并不是所有串行链路均连接至WAN。
LAN（而非WAN）可在组织中提供终端用户网络连接。
4电路交换WAN 技术的两个常见类型是什么？（请选择两项。
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1.请参见图示。
当使用链路状态路由协议的路由器D 添加到网络中后，在它了解网络拓扑结构的过程中，其所做的第一件事是什么？
它向路由器 B 和 C 发送LSP 数据包。
它向网络中的所有路由器发送LSP 数据包。
它向网络中的所有路由器发送Hello 数据包。
它向路由器 A 和 E 发送有关其直连邻居的信息。
它向网络中的所有路由器发送有关其直连邻居的信息。
当其接口处于up 状态时，它便能获知自己的直连网络。
2.哪两种事件将会导致链路状态路由器向所有邻居发送LSP？（选择两项。
）
30 秒计时器超时
网络拓扑结构发生变化时
运行贝尔曼-福特算法之后立即发送
DUAL FSM 建立拓扑数据库之后立即发送
路由器或路由协议初次启动时
3.链路状态路由过程的最后一步是什么？
将后继路由加入路由表中
SPF 计算到达每个目的网络的最佳路径
向所有邻居发送LSP 以收敛网络
运行DUAL 算法以找出到达目的网络的最佳路径
4.哪两项陈述正确描述了链路状态路由过程？（选择两项。
）
区域中的所有路由器都有链路状态数据库
区域中的每个路由器都将向所有邻居发送LSP
LSP 使用保留的组播地址224.0.0.10 来访问邻居
通过运行扩散更新算法(DUAL) 来防止路由环路
可靠传输协议(RTP) 是用于发送和接收LSP 的协议
5.请参见图示。
在从路由器JAX 发送到路由器ATL 的LSP 中，可以看到哪种类型的信息？
跳数
路由的正常运行时间
链路的开销
正在使用的所有路由协议的列表
6.现代链路状态协议通过哪些功能来尽可能降低处理器和内存要求？
将路由拓扑结构分割成更小的区域
为路由计算分配较低的处理优先级
使用更新计时器限制路由更新
严格执行水平分割规则以减少路由表条目
7.为使网络达到收敛，每台链路状态路由器会执行哪三个步骤？（选择三项。
）
使用自动总结缩小路由表大小
构建一个链路状态数据包(LSP)，其中包含每条直连链路的状态
向所有邻居发送LSP，邻居随后把接收到的所有LSP 存储到数据库中
按一定时间间隔发送Hello 数据包来发现邻居并建立相邻关系
构建完整的拓扑图并计算到达每个目的网络的最佳路径
使用DUAL FSM 选择有效且无环路的路径，并将路由插入到路由表中8..在使用链路状态路由的网络中，什么可以加速收敛过程？
由网络变更触发的更新
按固定间隔发送的更新
仅发送给直连邻居的更新
包含完整路由表的更新
9.为什么使用链路状态路由的网络中很少发生路由环路？
每台路由器都根据跳数建立起对网络的直观印象。
路由器在网络中发送大量LSA 以检测路由环路。
每台路由器都建立起对网络的完整而且同步的印象。
路由器使用抑制计时器来防止路由环路。
10.与距离矢量路由协议相比，链路状态路由协议有哪两项优势？（选择两项。
）
由于有了拓扑数据库，不再依赖于路由表。
每台路由器独立确定到每个网络的路由。
链路状态协议对路由器处理器能力的要求比距离矢量协议更低。
在初始LSP 泛洪后，传播拓扑结构的变更时占用更小带宽。
通过频繁发送定期更新，拓扑数据库中不正确路由数目降至最低。
11.链路状态路由协议运行什么算法来计算到达目的网络的最短路径？
DUAL
Dijkstra
贝尔曼-福特
Diffie-Hellman
12.请参见图示。
如果使用链路状态路由协议，以下哪项陈述正确描述了从10.0.0.0/24 网络到192.168.1.0/24 网络的流量所
用的路径？
BOS -> ATL，因为该路径的跳数最少
BOS -> ATL，因为该路径的开销最高
BOS -> ORL -> JAX -> ATL，因为该路径开销最低
流量将在所有链路间实施负载均衡
13.为了构建准确的SPF 树，区域内所有链路状态路由器上的哪个数据库或表必须相同？
路由表
邻接表
链路状态数据库
邻居表
拓扑数据库
14.以下哪两种路由协议使用Dijkstra 的最短路径优先算法？（选择两项。
）
RIPv1
RIPv2
IS-IS
BGP
EIGRP
OSPF
15.链路状态数据包何时发给邻居？
每30 秒
每180 秒
抑制计时器超时之后
链路进入运行状态或断开时
发生路由环路时
16.请参见图示。
JAX 会如何处理来自ORL 的链路状态数据包？
向ORL 和BOS 路由器发送其更新后的路由表
将单独的链路状态数据包从连接到BOS 的接口发送出去
查询BOS 以了解是否有更佳的路由
只将其添加到本地路由表中，不执行任何其它操作
17.新任网络管理员的任务是为某软件开发公司选择合适的动态路由协议。
该公司拥有超过100 台路由器，使用CIDR
和VLSM，要求快速收敛，并能同时使用Cisco 和非Cisco 设备。
该公司适合采用哪种路由协议？
RIP 第2 版
IGRP
EIGRP
OSPF
BGP
18.链路状态路由器在接收到来自邻居路由器的LSP 后会立即执行什么操作？
向邻居发送LSP
计算SPF 算法
运行贝尔曼-福特算法
计算到达目的网络的最佳路径
19.请参见图示。
如果所有路由器和接口都配置为使用链路状态路由协议，则路由器D 将从哪台路由器收到hello 数据包？
A 和E
B 和C
A、B、C 和E
仅C。