CCNA必考EIGRP解析
混合路由协议EIGRP
CCNA 640-802
路由发现和维护
邻居表：以建立的邻居关系
拓扑表：互联网中每个路由器从每个邻居 接受到的路由宣告 路由表：存储最佳路由 度量：带宽，延迟，负载，可靠性，最大传输单 元(MTU)
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CCNA 640-802
• Displays the neighbors discovered by IP EIGRP
Router#show ip eigrp topology
• Displays the IP EIGRP topology table
Router#show ip route
• Displays current EIGRP entries in the routing table
CCNA 640-802
术语
• AD = 下一跳路由器到达目标网络的开销 • FD = 本地路由器到达目标网络的总开销 • 后继路由器(successor) = 到达目标网络的下一跳路 由器 • 可行后继路由器(FS) = 后继路由器的备份
© 2009, aoshinfo training. All rights reserved.
配置 EIGRP
Router(config)#router eigrp {as-number} • 启动EIGRP
Router(config-router)#network {network-number}
• 宣告直连主类网络号
© 2009, aoshinfo training. All rights reserved.
第九章 混合路由协议(EIGRP)
© 2009, aoshinfo training. All rights reserved.
CCNA(200-120)考试个人笔记及注意事项
01CCNA考试个人笔记1.选择题1.交换1.二层交换机：分割减少冲突，这里不是冲突域；收到未知的帧将会泛洪；2.MAC地址的作用：在二层唯一确定一台设备；使同一网络的不同设备可以通信；3.IEEE802.3标准规定了以太网的物理层和数据链路层的MAC子层；4.在交换机新建一个vlan，等于增加了一个广播域，冲突域的个数不变；5.vlan的作用：逻辑微分组、安全性、增加广播域；路由器一个接口是一个广播域，一个vlan也是一个广播域；交换机一个接口是一个冲突域；集线器的所有接口都在一个冲突域中；6.要想远程管理交换机，需要在交换机上配置ip default-gateway和interface vlan；7.查看Trunk的命令：show interface trunk和show interface switchport；8.交换机为什么从不学习广播地址？因为广播地址永远不会成为一个帧的源地址；9.Trunk链路的模式有auto、on和desirable；auto：不会主动发DTP信息；on：强制成为trunk，也主动发DTP信息；desirable：DTP主动模式，发DTP和对方协商；一端已经设置为auto模式，另一端必须设置为desirable模式才能协商成trunk；10.RSTP的优点：能够减少汇聚时间；比STP增加端口角色alternate和backup；在点到点链路提供比STP更快的传输和转发；11.VLAN的特点：微分段、安全性、灵活性；一个VLAN＝一个广播域＝逻辑网段(子网)；Trunk协议有两种，一种是通用的802.1Q协议，一种是cisco专用的ISL协议；12.VTP管理VLAN的范围是1~1005，而可以修改的VLAN范围是2~1002；13.要实现VLAN间路由，有三种接口需要配置：Access接口、Trunk接口、SVI接口；14.802.1Q native vlan是不做标记的，所以在trunk两边的native需要一致；15.哪一个环境下交换机在vlan出现多个相同的单播帧？拓扑中有不合适的冗余；in an improprely implemented redundant topology；16.EtherChannel中两个端口需要speed一致；在EtherChannel中，端口上那一项参数可以配置不一样？DTP negotiation settings；2.路由1.路由器的TTL值默认是255；2.距离矢量协议：周期性向邻居广播整个路由表；4.EIGRP建立邻居关系必须满足本个条件：收到Hello或ACK、具有匹配的As号、具有相同的度量(K值)；默认情况下，EIGRP是不支持VLSM的，我们可以通过关闭EIGRP的自动汇总来让EIGRP 支持VLSM；3.OSPF为什么要划分区域：减少路由表大小、限制LSA的扩散、加快OSPF收敛速度、增加OSPF稳定性；OSPF的BR的选举：优先级＋RouterID；链路状态协议的特点：提供查看拓扑的命令，show ip ospf database；计算最短路径；利用触发更新；邻居之间只能交换LSA，但不能交换路由信息；4.OSPF的进程号仅仅具有本地意义，进程号不同不影响邻居关系的建立；使用单区域OSPF的好处：减少了LSA的种类，不需要虚电路；5.哪一个OSPF命令可以把所有端口划分进area 0?network 0.0.0.0 255.255.255.255 area 06.PPP在进行认证配置的时候，用户名要是对端的用户名，但是password要是两边共享的password；3.综合1.CSU/DSU是用于连接终端和数字专线设备，Modem用于数字信号和模拟信号的转换，两者都属于DCE设备；路由器一般属于DTE设备；A CSU/DSU converts digital signals from a router to leased line.A modem convert digital signals from a router to a phone line.2.在半双工网络中才存在冲突域；3.Ipv6的任意播：closet、nearest、same dress for mutiple devices；one-to-one of nearest；4.查看CPU利用率：show process；5.默认网关的配置方法：ip route 0.0.0.0 0.0.0.0 s0/1ip default-network 0.0.0.06.反掩码加1就是块大小，块大小减1就是反掩码；7.IOS的存放位置只能是自身的flash或TFTP server中；8.网络工程师想要允许一个临时与一个特定的username远程用户和密码，这样用户可以访问整个网络，which ACL可以使用？动态ACL；9.静态ACL：一直在NA T表中；允许来自外部的链接；10.哪一个命令可以验证哪些接口受到了ACL的影响？show ip interface；show ip access-list，显示访问控制列表；show access-lists，显示当前所有ACL的内容；show interface [int]，查看某个接口的物理层和数据链路层的信息，如MAC地址，封装方式等；show ip interface [int]，提供路由器接口的第三层配置信息，如接口状态，IP地址，访问控制列表等；11.show interface fa0/1，出现错误报文，可能是因为双工不匹配或者链路状态不稳定等因素造成的；12.DHCP检测到地址冲突，会把这个地址移出地址池，这个地池将不再分配，直到管理员解决冲突；2.拖图题1. show ip interface如：FastEthernet0/0 is up, line protocol is down (disabled)第一个up/down涉及物理层，第二个up/down涉及数据链路层(clock rate或者封装问题)2. show interfaces [int] 查看的是某个interface的物理层和数据链路层的信息，它给出了硬件地址，逻辑地址和封装方式的信息。
思科CCNA新版第3学期final-期末考试答案
思科CCNA新版第3学期final-期末考试答案1出于维护目的，已将路由器从网络中移除。
并已将新的 Cisco IOS 软件映 像成功下载到服务器并复制到路由器的闪存中。
应该在进行什么操作后再 将路由器放回网络中运行？备份新的映像。
将运行配置复制到 NVRAM 。
从闪存中删除之前版本的 Cisco IOS 软件。
重新启动路由器并检验新的映像是否成功启动。
答案 说明最高分值correctness of response Option 422请参见图示。
管理员尝试在路由器上配置 IPv6 的 EIGRP ，但收到如图所示 的错误消息。
配置 IPv6 的 EIGRP 之前，管理员必须发出什么命令？no shutdowneigrp router-id 100.100.100.100ipv6 unicast-routingipv6 eigrp 100ipv6 cef答案 说明 最高分值correctness of response Option 323IPv6 EIGRP 路由器使用哪个地址作为 hello 消息的来源？32 位路由器ID接口上配置的 IPv6 全局单播地址所有 EIGRP 路由器组播地址接口 IPv6 本地链路地址答案 说明 最高分值correctness of response Option 424下列关于 EIGRP 确认数据包的说法，哪两项是正确的？（请选择两项。
）发送该数据包是为了响应 hello 数据包。
该数据包用于发现接口上连接的邻居。
该数据包作为单播发送。
该数据包需要确认。
该数据包不可靠。
答案 说明 最高分值correctness of response Option 3 and Option 5 are correct.25何时发送 EIGRP 更新数据包？仅在必要时当获取的路由过期时每 5 秒通过组播发送每 30 秒通过广播发送答案 说明 最高分值correctness of response Option 126请参见图示。
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。
Eigrp 总结
Eigrp 的总结：一、特点：1.高级距离失量；2.组播和单播的更新方式；3.支持多种网络层协议4.100%无环路无类路由；5.快速收剑；6．增量更新；7.灵活的网络设计；8.支持VLSM和不连续子网；9.支持等价负载均衡和非等价负载均衡；10.在W AN和LAN链路的配置简单；11.支持在任何点可以手动汇总；12.丰富的度量。
二、关键技术1第一个关键技术：---------------多协议模块：Eigrp 是个不可靠的协议。
因为是封装在IP网络层。
怎样保证可靠传输？A:用序列号（sequence）B:用确认号(acknowledge)2第二个关键技术：------------RTP 协议保证可靠传输：RTP定义了eigrp的五种结构：Hello包：Update包：是可靠的包，正常情况下，使用组播地址：224.0.0.10.发送后必须收到一个单播的回复。
也就是确认单播发送的。
组播发出后，经过一个“组播流计时器”时间后，仍然没有收到ACK，则要重传；重传的方式变为单播。
经过单播重传记时器RTO还没有收到回复，则一直重传。
重传16次则认为邻居关系不存了）查询包：回复包：确认包：另外还有两个包：SIA查询包和SIA回复包（stuck in active卡在活动状态）本节中有一个抓包试验：如图：R1,在全局下：要做从交换机的f0/0接口映射到f0/15接口，这样数据也能够经过f0/15接口，才能利用真实机抓到R1到R2数据包。
可以分析数据包的结构。
配置Sw1config#:monitor session 1 source interface fastethernet 0/0 both( 双向)最后还可以定其它的参数：如RX（只收）、TX（只发）、，（用，号分开可以接多个接口）和-（用-连接接口）等Monitor session 1 destintion interface f0/153.第三个关键技术：---------------邻居的发现与恢复：邻居的发现过程：-------------三次握手：利用Holle包，来发现邻居；R1：Hello --------------------------→R2 第一次<————————hello 第二次<————————updateACK------------------------→第三次update----------------------→holle 时间为5秒，失效时间为15秒；抖动时间：可以忽略不计。
ERouting Final Exam - CCNA Exploration 路由协议和概念 (版本 4.0) (思科第二学期期末答案)
ERouting Final Exam - CCNA Exploration: 路由协议和概念 (版本 4.0) (思科第二学期期末答案)参加考试 - ERouting Final Exam - CCNA Exploration: 路由协议和概念 (版本 4.0)1.请参见图示。
哪一项是对连接到路由器 R1 的路由的最有效总结？198.18.0.0/16198.18.48.0/21198.18.32.0/22198.18.48.0/23198.18.49.0/23198.18.52.0/222.下列关于路由协议的陈述，哪三项是正确的？（选择三项。
）EIGRP 支持不等价负载均衡。
RIP 无法配置为允许无类路由。
OSPF 在多路访问链路上选举指定路由器。
RIP 不通告跳数超过 15 的路由。
EIGRP 使用广播流量与其邻居建立相邻关系。
OSPF 能够更迅速地收敛，因为在后继路由失效时，它能够在其拓扑表中找出可行后继路由。
3.请参见图示。
该网络正在运行 RIP 路由协议。
网络 10.0.0.0 突然断开。
下列有关此拓扑结构中路由器如何响应该事件的陈述中，哪一项是正确的？Router4 将在 30 秒之后的下一次定期更新中获知该失效路由。
在抑制计时器超时之前，水平分割将阻止 Router4 向 10.0.0.0 网络转发数据包。
Router5 将立即从路由表中清除这一失效路由。
Router5 将向 Router4 发送触发更新，其中网络 10.0.0.0 的度量为 16。
4.请参见图示。
根据图中所示的拓扑结构，要在 Paris 路由器上配置 EIGRP 需要使用哪三条命令？（选择三项。
）Paris(config)# router eigrp 100Paris(config)# router eigrpParis(config-router)# network 192.168.6.0Paris(config-router)# network 192.168.7.0Paris(config-router)# network 192.168.8.0Paris(config-router)# network 192.168.9.05.请参见图示。
CCNA 实验题 EIGRP排错 对照翻译
1. EIGRPQuestion:After adding BLD-102 router, no routing updates are being exchanged between BLD-102 and the new location. All other inter connectivity and Internet access for the existing locations of the company are working properly.The task is to identify the fault(s) and correct the router configuration to provide full connectivity between the routers.Access to the router CLI can be gained by clicking on the appropriate host. All passwords on all routers are cisco.IP addresses are listed in the chart below.注意：考试时，点路由连接的console（虚线）进入配置进入路由BLD-102BLD-102>enable（密码cisco）BLD-102#show run…………（查看错误，是AS号错或者网段宣告错误）AS号错：BLD-102#configure terminal（conf t）进入全局BLD-102（config）#no router eigrp 22 删掉eigrpBLD-102（config）#router eigrp 212 重新添加eigrpBLD-102（config-router）#network 192.168.22.0 重新宣告网段BLD-102（config-router）#network 192.168.60.0BLD-102（config-router）#no auto-summary 不要忘记关闭自动汇总BLD-102（config-router）#endBLD-102#copy running-config startup-config 不要忘记保存（配置完成后，可以再通过show run 查看一下是否配置成功）宣告错误：BLD-102#configure terminal（conf t）进入全局BLD-102（config）#router eigrp 212 进入eigrp212BLD-102（config-router）#no network 192.168.22.0 删除多余的网段BLD-102（config-router）#network 192.168.60.0 添加网段BLD-102（config-router）#endBLD-102#copy running-config startup-config 不要忘记保存（配置完成后，可以再通过show run 查看一下是否配置成功）。
ccna考试题库最新版
ccna考试题库最新版CCNA（Cisco Certified Network Associate）认证是全球范围内最受欢迎的网络工程师认证之一，具备CCNA认证可以证明一个人在建立、规划、运行、安装和配置中等规模的局域网和广域网方面的专业知识。
为了帮助广大考生顺利通过CCNA考试，不断更新的CCNA考试题库至关重要。
以下是最新版本的CCNA考试题库，希望对考生们有所帮助。
第一部分：网络基础知识1. 什么是OSI七层模型？简要介绍每一层的功能。
2. TCP和UDP之间有哪些区别？请分别举例说明。
3. 什么是IP地址？IP地址的类型有哪些？请列举并简要介绍各自的特点。
4. 什么是子网掩码？为什么在网络中使用子网掩码？5. 简述常见的网络设备有哪些，以及各自的功能与作用。
第二部分：路由和交换技术1. 路由器和交换机之间有何区别？请进行比较并指出各自的优势和劣势。
2. 什么是VLAN？VLAN的作用及在网络中的应用场景是什么？3. OSPF和EIGRP是两种常见的路由协议，请比较它们的特点并举例说明。
4. 请解释静态路由和动态路由的概念以及在网络中的应用。
5. 交换机在网络中扮演什么角色？交换机的MAC地址表是如何工作的？第三部分：网络安全和管理1. 网络安全的重要性是什么？请列举几种常见的网络安全威胁并介绍应对策略。
2. 什么是ACL（访问控制列表）？ACL的作用是什么？请给出一个ACL的配置示例。
3. VPN是什么？VPN的工作原理及在企业网络中的应用。
4. SNMP是网络管理中常用的协议，它的作用是什么？请解释SNMP中的几个重要概念。
5. 如何保护无线网络的安全？请列举几种方法。
第四部分：WAN技术1. 什么是WAN？WAN的主要特点是什么？2. PPP协议和HDLC协议分别是什么？请比较它们的异同。
3. 什么是Frame Relay？Frame Relay的工作原理及在WAN中的应用。
4. 请解释T1和E1的概念，以及它们在传输速率和应用方面的差异。
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。
CCNA完整知识点.
chapter 1L1：物理层PDU：bits 比特流作用：传输比特流（01000100101010...）介质：同轴电缆： coaxial cable 传输距离 500米双绞线（TP）：twisted-pair cable 传输距离 100米非屏蔽双绞线（UTP）：室内屏蔽双绞线（STP）：室外（环境干扰强）直通线：AA BB 链接异性端口：pc-hub pc-sw sw-router交叉线：AB 链接同性端口:pc-pc router-router pc-router sw-sw反线：1-8 8-1 用于本地连接的console 控制线网线的两种制作方式：568A:白绿绿白橙篮白蓝橙白棕棕568B:白橙橙白绿篮白蓝绿白棕棕 1236 网线使用DCE：数据终端设备，需要配置clock rate DTE：数据终结设备对应传输介质的支持传输距离：1）1000base-cx 使用的是铜缆。
最大传输距离25米2）100Base-Tx/Fx100Base-Tx以5类非屏蔽双绞线为传输介质（最大传输距离是100米）100Base-Fx以光纤为传输介质（2000米）。
3）1000base-SX（MMF多模）：最长传输距离是550米4）1000base-LX：可以使用单模光纤也可以使用多模光纤使用多模光纤的最大传输距离为550m，使用单模光纤的最大传输距离为3千米5）1000base-zx（单模）：最长传输距离是70KM以太网 Ethernent传输模式：单工:只能发或者收半双工：即可以收也可以发，但是同一时间只能收或者发列如对讲机全双工：同一时间既可以收也可以发列如手机Auto：中继器（Repeater）：对信号放大，双绞线的传输距离只有100M，使用中继器可以延长传输距离。
hub ：多口中继，一个数据帧从一个入口进，会发送到HUB的所有其他端口而不进行过滤。
L2：数据链路层PDU：frame 帧作用：成帧，差错控制设备：网桥（bridge）：基于MAC地址转发，根据mac-port表，数据包只发到和MAC地址相对应的port端口交换机（switch）：多口网桥，独享带宽L2层编制：MAC地址MAC地址构成：48bit，12位十六进制数可以通过ipconfig/all 查询电脑的mac地址L2表：MAC-port表（mac地址表）冲突域：不可避免的数据冲突范围，由中继、hub链接构成并扩大，见到L2层端口截止，每一个交换机端口形成一个冲突域HUB：所有端口都在一个冲突域，是增加了冲突域的范围交换机：没一个端口都是一个冲突域，是增加了冲突域的数量，减少了冲突域的范围HUB：是共享带宽 10M 所有端口共享10M交换机：独享带宽 10M 每个端口同时有10ML3：网络层 PDU：packet 包作用：逻辑编制：ip地址、路由（路径的选择）IP地址与mac地址的区别？Mac地址通信：同一个网络，mac通信跨网络通信：ip地址IP地址：版本v4；32bit；点分是进制法 192.168.0.1IP=网络位+主机位掩码：mask：连续的1+连续的0，来确定IP地址的网络位+主机位，1位对应网络位，0位对应主机位。