CCNA Study Notes1(1)-思科认证试题
CCNA Study Notes1(1)-思科认证试题
1. Identify and describe the functions of each of the seven layers of the OSI reference model. Physical Layer
The physical layer defines the electrical, mechanical, procedural, and functional specifications for activating, maintaining, and deactivating the physical link between communicating network systems. Physical layer specifications define such characteristics as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, and the physical connectors to be used.
Data Link Layer
The data link layer provides reliable transit of data across a physical network link. Different data link layer specifications define different network and protocol characteristics, including the following:
Physical addressing --Physical addressing (as opposed to network addressing) defines how devices are addressed at the data link layer.
Network topology -- Data link layer specifications often define how devices are to be physically connected (such as in a bus or a ring topology).
Error notification -- Error notification involves alerting upper layer protocols that a transmission error has occurred.
Sequencing of frames --Sequencing of data frames involves the reordering of frames that are transmitted out of sequence.
Flow control -- Flow control involves moderating the transmission of data so that the receiving device is not overwhelmed with more traffic than it can handle at one time.
The Institute of Electrical and Electronics Engineers (IEEE) has subdivided the data link layer into two sublayers: Logical Link Control (LLC) and Media Access Control (MAC).
Network Layer
The network layer provides routing and related functions that allow multiple data links to be combined into an internetwork. This is accomplished by the logical addressing (as opposed to the physical addressing) of devices. The network layer supports both connection-oriented and connectionless service from higher-layer protocols.
Transport Layer
The transport layer implements reliable internetwork data transport services that are transparent to upper layers. Transport layer functions typically include the following:
Flow control -- Flow control manages data transmission between devices so that the transmitting device does not send more data than the receiving device can process.
Multiplexing -- Multi。
思科认证CCNA认证试题和答案中文版
思科认证CCNA认证试题和答案中文版思科认证CCNA认证试题和答案中文版想要获得思科认证，首先要参加由思科推荐并授权的培训中心(Cisco Training Partner，简称CTP)所开设的培训课程。
完成学业后再到由全球考试机构Sylvan Prometric授权的.考试中心参加由思科指定的科目的认证考试。
通过指定的系列科目考试后，学员就可以获得相应分支系列等级的资格认证。
下面是店铺为大家搜集的相关试题，供大家参考练习。
16、路由器A串口0配置如下interface serial0link-protocol pppppp pap local-user huawei password simple quidwayip address 2.2.2.1 255.0.0.0路由器B串口及全局配置如下local-user huawei service-type ppp password simple quidway!interface serial0link-protocol pppppp authentication-mode papip address 2.2.2.2 255.0.0.0当两台路由器串口0相连时，两台路由器是否可以连接到对端()(A) 能(B) 不能答案：A17、关于千兆以太网，以下说法正确的是( )(A) IEEE802.3ab定义了千兆以太网(B) 在同一冲突域中，千兆以太网不允许中继器的互连(C) IEEE802.3z专门定义了千兆以太网在双绞线上的传输标准(D) 千兆以太网支持网络速率的自适应，可以与快速以太网自动协商传输速率答案：AB参考知识点：华为3com认证教材第一册3-8页18、高层的协议将数据传递到网络层后，形成( )，而后传送到数据链路层(A) 数据帧(B) 信元(C) 数据包(D) 数据段答案：C参考知识点：华为3com认证教材第一册1-20页19、在路由器上配置帧中继静态map必须指定( )参数(A) 本地的DLCI(B) 对端的DLCI(C) 本地的协议地址(D) 对端的协议地址答案：AD20、路由器的主要性能指标不包括( )(A) 延迟(B) 流通量(C) 帧丢失率(D) 语音数据压缩比答案：D【思科认证CCNA认证试题和答案中文版】。
思科认证CCNA认证试题与答案中文版
答案：D 注释:这个题目不是太严谨,应该加上子网掩码. A:224. 0. 0. 5 是多播地址 B: 127. 0.0. 0 保留作为测试使用 C:网络地址 26、 设置主接口由 up 转 down 后延迟 30 秒切换到备份接口，主 接口 由 down 转 up 后 60 秒钟切换回主接口的配置为()
忍一句，息一怒，饶一着，退一步。——《增广贤文》
人之为学，不日进则日退，独学无友，则孤陋而难成；久处一方，则习染而不自觉。——《顾炎武》
答案：D 注释:255. 255. 255. 255 是全网广播,DHCP 客户端发送全网广播来 查 找 DHCP 服务器. 24、 下而有关 NAT 叙述正确的是() (A) NAT 是英文“地址转换”的缩写，又称地址翻译 (B) XAT 用来实现私有地址与公用网络地址之间的转换 (C) 当内部网络的主机访问外部网络的时候，一定不需要 NAT (D) 地址转换的提出为解决 IP 地址紧张的问题提供了一个有效途 径 答案:ABD 25、 以下属于正确的主机的 IP 地址的是()
(A) arp-a (B) traceroute (C) routeprint (D) displayiprouting-table
答案：D 23、 D0. 0. 0 (B) 10. 0. 0. 1 (0127. 0. 0. 1 (D)255. 255. 255. 255
192. 168. 1. 1
答案：D 注释:PC 的'默认网关要指向路由器的以太网口的 IP 地址. 28、 ISDNB 信道速率是()
(A) 16kbps (B) 64kbps
Cisco CCNA 认证考试最新真题
Cisco CCNA 认证考试最新真题体验1. The command frame-relay map ip 10.121.16.8 102 broadcast was entered on the router. Which of the following statements is true concerning this command?A.This command should be executed from the global configuration mode.B.The IP address 10.121.16.8 is the local router port used to forward data.C.102 is the remote DLCI that will receive the information.D.The broadcast option allows packets, such as RIP updates, to be forwarded across the PVC2. While troubleshooting a network connectivity problem, a technician observes steady link lights on both the workstation NIC and the switch port to which the workstation is connected. However, when the ping command is issued from the workstation, the output message "Request timed out." is displayed. At which layer of the OSI model does the problem most likely exist?A.the session layerB.the network layerC.the data link layerD.the access layer3. In order to allow the establishment of a Telnet session with a router, which set of commands must be configured?A.router(config)# line console 0router(config-line)# enable password ciscoB.router(config)# line console 0router(config-line)# enable secret ciscorouter(config-line)# loginC.router(config)# line console 0router(config-line)# password ciscorouter(config-line)# loginD.router(config)# line vty 0router(config-line)# password cisco router(config-line)# login4. On point-to-point networks, OSPF hello packets are addressed to which address?A.127.0.0.1B.192.168.0.5C.224.0.0.5D.254.255.255.2555. What should be part of a comprehensive network security plan?A.Allow users to develop their own approach to network security.B.Physically secure network equipment from potential access by unauthorized individualsC.Encourage users to use personal information in their passwords to minimize the likelihood of passwords being forgottenD.Delay deployment of software patches and updates until their effect on end-user equipment is well known and widely reported6. During startup, the router displays the following error message:boot: cannot open "flash:" What will the router do next?A.Because of damaged flash memory, the router will fail the POST.B.It will attempt to locate the IOS from a TFTP server. If this fails, it will initiate the setup dialogC.It will attempt to locate the IOS from a TFTP server. If this fails, it will load a limited IOS from ROM.D.It will attempt to locate the configuration file from a TFTP server. If this fails, it will initiate the setup dialog7. At which OSI layer is a logical path created between two host systems?A.sessionB.transportworkD.physical8. A routing protocol is required that supports:1) routing update authentication2) an addressing scheme that conserves IP addresses3) multiple vendors4) a network with over 50 routersWhich routing protocol fulfills these requirements?A.RIPv1B.RIPv2C.EIGRPD.OSPF9. When a new trunk is configured on a 2950 switch, which VLANs by default are allowed over the trunk link?A.no VLANsB.all VLANsC.only VLANs 1 - 6D.only the VLANs that are specified when creating the trunk10. Which protocol provides a method of sharing VLAN configuration information between switches?A.VTPB.STPC.ISLD.802.1QDBDCB CCDBA博主的更多文章>>CCNA第一学期《Final Examination》2009-02-27 08:58:47 标签：CCNA[推送到技术圈]1请参见图示。
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及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,192.168.19.255/20,下列说法正确的是: （）(A) 这是一个广播地址(B) 这是一个网络地址(C) 这是一个私有地址(D) 地址在192.168.19.0网段上(E) 地址在192.168.16.0网段上(F) 这是一个公有地址答案：CE注：IP地址中关键是看她的主机位，将子网掩码划为二进制，1对应上面的地址是网络位，0对应的地址是主机位192.168.19.255/20划为二进制为：11000000.10101000.00010011.1111111111111111.11111111.11110000.00000000主机位变成全0表示这个IP的网络地址主机槐涑扇?表示这个IP的广播地址RFC1918文件规定了保留作为局域网使用的私有地址：10.0.0.0 - 10.255.255.255(10/8 prefix)172.16.0.0 - 172.31.255.255 (1 72.16/12 prefix)192.168.0.0 - 192.168.255.255 (192.168/16 prefix)3、Quidway系列路由器在执行数据包转发时，下列哪些项没有发生变化（假定没有使用地址转换技术）？（）(A) 源端口号(B) 目的端口号(C) 源网络地址(D) 目的网络地址(E) 源MAC地址(F) 目的MAC地址答案：ABCD参考知识点：路由功能就是指选择一条从源网络到目的网络的路径，并进行数据包的转发。
CISCOCCNA网络工程师题库
CISCOCCNA网络工程师题库CCNA题库考试代号：640-802考试时刻：英文110+30=140分钟通过分数：825题库版本：V104.4鸿鹄论坛招募CCNA、CCNP答疑讲师答疑地点：鸿鹄官方YY频道3660鸿鹄大讲堂：://bbs.hh010 /thread-46172-1-1.htmlCCNA题库战报交流QQ群：144288127 （500人超级群）CCNA题库战报交流区：://bbs.hh010 /forum-261-1.html1000 G视频教程免费下载：://bbs.hh010 /forum-228-1.htmlCCNA（640-802）题库V104.4CCNA（640-802）题库V104.4（情人节版）CCNA 题库战报500人超级QQ群144288127V104系列是官方的终结版本，以后可不能再出V105 V106 V108等等CCNA 最新题库/最新战报公布区：://bbs.hh010 /forum-261-1.html下载官方正版题库、看最新考试战报，请随时关注鸿鹄论坛://bbs.hh010CCNA考试报名1900，详情请联系鸿鹄全国区十七名客服QQ 712023090-712023106========================================更新内容：V104.1修正V104中错误题目，确定经典争议题目答案；V104.2增加拖图题并可完美模拟考试，VCE题库增加中文注释；V104.3针对思科CCNA考试变题，更新考试新增题目93Q,更新V104.2实验题；V104.4增加全文中文注释，汇总V104.3九次更新，删除部分旧题目，为目前最新官方正版题库；2011.8.1 增加每日新题，修订部分错误。
2020.2.14 情人节版增加5道新题，分别是519、520、521、522、523题修改176题、375题、443题、482题答案错误修改59题、88题、453题、107题、270题注释错误增加个别疑难拖图题注释，优化实验题=============================================QUESTION 1When you are logged into a switch, which prompt indicates that you are in privileged mode? (当您登录到交换机，哪种提示说明你在特权模式？)A. %B. @C. >D. $E. #Answer: ESection: Chapter 4: Introduction to Cisco IOSExplanation/Reference:特权模式确实是#提示符QUESTION 2Which command shows system hardware and software version information?(哪些命令显示系统硬件和软件的版本信息？)A. show configurationB. show environmentC. show inventoryD. show platformE. show versionAnswer: ESection: Chapter 4: Introduction to Cisco IOSExplanation/Reference:查看系统的软件和硬件信息使用的命令是show versionQUESTION 3Cisco Catalyst switches CA T1 and CAT2 have a connection between them using ports FA0/13. An 802. 1Q trunk is configured between the two switches. On CAT1, VLAN 10 is chosen as native, but on CA T2 the native VLAN is not specified.What will happen in this scenario?(思科Catalyst 交换机CAT1 和CAT2 有它们之间的连接使用端口FA0/13。
ccna考试试题库
ccna考试试题库CCNA（Cisco Certified Network Associate）考试是思科认证网络专家的初级认证，主要测试考生在网络基础、路由、交换、无线和安全等方面的知识。
以下是一些模拟CCNA考试的试题和答案：1. 什么是子网掩码，它有什么作用？答案：子网掩码是一种IP地址的附加信息，用于指定IP地址中网络部分和主机部分的界限。
它的作用是允许路由器区分IP地址中的网络地址和主机地址，从而实现不同网络之间的路由。
2. 描述静态路由和动态路由的区别。
答案：- 静态路由：由网络管理员手动配置的路由信息，不随网络结构的变化而自动调整。
- 动态路由：由路由器根据网络拓扑的变化自动生成和更新的路由信息。
3. 什么是VLAN，它有什么好处？答案： VLAN（虚拟局域网）是一种在交换机上划分不同网络的技术，即使物理上连接在同一交换机上，也可以属于不同的VLAN。
VLAN的好处包括提高安全性、减少广播域、提高网络管理的灵活性等。
4. 简述TCP和UDP的区别。
答案：- TCP（传输控制协议）：提供可靠的、面向连接的传输服务，有流量控制和拥塞控制机制。
- UDP（用户数据报协议）：提供不可靠的、无连接的传输服务，适用于对实时性要求高的应用。
5. 什么是DHCP，它的作用是什么？答案： DHCP（动态主机配置协议）是一种网络管理协议，用于自动分配IP地址和其他网络配置信息给网络中的设备。
它的作用是简化网络配置，避免IP地址冲突。
6. 什么是NAT，它在网络中扮演什么角色？答案： NAT（网络地址转换）是一种技术，允许多个设备共享一个公共IP地址与互联网通信。
它在网络中扮演的角色是节省IP地址资源，隐藏内部网络结构。
7. 什么是STP（生成树协议）？答案： STP（生成树协议）是一种网络协议，用于在局域网中防止网络环路的产生。
通过创建一个无环的逻辑拓扑，STP确保网络的稳定性和可靠性。
8. 描述OSPF（开放最短路径优先）协议的工作原理。
思科认证网络工程师【CCNA 1-2】 OSI七层协议概述及线缆介绍
L2数据
传输媒体
物理层
从数据链路层
L2数据
到数据链路层
物理层
允许接入网络资源
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
建立、管理和终止会话
将分组从源端传送到目的端； 提供网络互联
在媒体上传输比特； 提供机械的和电气的规约
对数据进行转换、 加密和压缩
提供可靠的端到端的 报文传输和差错控制
将分组数据封装成帧； 提供节点到节点方式的传输
物理层设备-集线器
A
B
C
D
Physical
所有的设备在同一个冲突域 (collision domain) 所有的设备都在同一个广播域( broadcast domain) 设备共享带宽
终端站点越多，冲突(域)越大 采用CSMA/CD机制
物理层设备-集线器
听
数据
现在的情况是PCA和PCC都要发数据,但是两人刚才都检测到HUB上是空闲的.那么两人都发.结果发生了冲突.两人都同时启动BACK OFF动作.随机的生成一个秒数,再发数据包.如果再与其他PC发送的数据包冲突.那么再次BACK OFF,BACK OFF一共可进行15次.
5.会话层
6.表示层
7.应用层
4.传输层
2.数据链路层
1.物理层
4.传输层
2.数据链路层
3.网络层
1.物理层
5.会话层
6.表示层
7.应用层
数据
3.网络层
2.数据链路层
3.网络层
1.物理层
2.数据链路层
3.网络层
1.物理层
应用层
应用层的作用： 为应用软件提供接口，使应用程序能够使用网络服务 常见的应用层协议： http(80)、ftp(20/21)、smtp(25)、pop3(110)、telnet(23)、dns(53)等
思科认证考试题库
CCNA640-802 V13题库试题分析题库讲解：吴老师（艾迪飞CCIE实验室首发网站：1. What are two reasons that a network administrator would use access lists? (Choose two.)A. to control vty access into a routerB. to control broadcast traffic through a routerC. to filter traffic as it passes through a routerD. to filter traffic that originates from the routerE. to replace passwords as a line of defense against security incursionsAnswer: AC解释一下：在VTY线路下应用ACL，可以控制从VTY线路进来的telnet的流量。
也可以过滤穿越一台路由器的流量。
2. A default Frame Relay WAN is classified as what type of physical network?A. point-to-pointB. broadcast multi-accessC. nonbroadcast multi-accessD. nonbroadcast multipointE. broadcast point-to-multipointAnswer: C解释一下：在默认的情况下，帧中继为非广播多路访问链路。
但是也可以通过子接口来修改他的网络的类型。
3．Refer to the exhibit. How many broadcast domains exist in the exhibited topology?A. oneB. twoC. threeD. fourE. fiveF. sixAnswer: C解释一下：广播域的问题，在默认的情况下，每个交换机是不能隔离广播域的，所以在同一个区域的所有交换机都在同一个广播域中，但是为了减少广播的危害，将广播限制在一个更小的范围，有了VLAN的概念，VLAN表示的是一个虚拟的局域网，而他的作用就是隔离广播。
思科第一学期期末考试最新考题CCNA1
1Refer to the exhibit. Which Layer 2 protocol could be used inside nework A and network C?IPTCPUDPEthernet2Refer to the exhibit. Which set of devices contains only intermediary devices?A, B, D, GA, B, E, FC, D, G, IG, H, I, J3Refer to the exhibit. The headers added at each layer are shown. Which layer adds the destination and source process num ensure that data is delivered to the correct application?physical layerdata link layernetwork layertransport layer4The Layer 4 header contains which type of information to aid in the delivery of data?service port numberhost logical addressdevice physical addressvirtual connection identifier5Which fiber connector supports full-duplex Ethernet?6Which device should be used for routing a packet to a remote network?access switchDHCP serverhubrouter7Refer to the exhibit. Host A sends a frame to host C with a destination MAC address CC. The MAC address for host C is no table of switch SW1. How will SW1 handle the frame?Switch SW1 will drop the frame.Switch SW1 will forward the frame to host C.Switch SW1 will flood the frame out all ports.Switch SW1 will flood the frame out all ports except port Fa0/1.8Refer to the exhibit. A network technician has made several changes to R1 since the configuration has last been saved. Th configuration did not produce the desired changes. The technician wants to store a backup copy of the saved configuration server before reloading. Which action will cause the unmodified data to be saved on the TFTP server?9Which three statements are true about network layer addressing? (Choose three.)It uniquely identifies each host.It assists in forwarding packets across internetworks.It uses a logical 32-bit IPv4 address.It is not a configurable address.It is a physical address.It identifies the host from the first part of the address.10What is the result of using the clock rate 56000 command at the serial interface of the router?The interface is configured as a DCE device.The interface timers are cleared.The FastEthernet interface is made to emulate a serial interface by assigning it a timing signal.The IP address for the serial interface is configured.11Examine the graphic with current configurations. Host A in the Clerical office failed and was replaced. Although a ping to 12 successful, the replacement computer cannot access the company network. With proxy ARP disabled on the Fa0/0 interfac York router, what is the likely cause of the problem?network card failurenetwork cables unpluggedIP address incorrectly enteredsubnet mask incorrectly entered12As network administrator, what is the subnet mask that allows 510 hosts given the IP address 172.30.0.0?255.255.0.0255.255.248.0255.255.252.0255.255.254.0255.255.255.0255.255.255.12813Which OSI layer uses a connection-oriented protocol to ensure reliable delivery of data?application layerpresentation layersession layertransport layer14 A network has grown too large for technicians to configure network addresses and hosts files for name resolution. Which twlayer services should be added to the server to allow these needs to be satisfied dynamically? (Choose two.)DNSFTPDHCPHTTPSMTP15Refer to the exhibit. Host A wants to access the Internet. Which combination of a Layer 2 address and a Layer 3 address w access from host A?Destination MAC: 0030.8596.DE83 Default gateway: 209.165.202.130Destination MAC: 0030.8596.DE82 Default gateway: 172.16.9.2Destination MAC: 0030.8517.44C4 Default gateway: 172.16.1.1Destination MAC: 0030.8517.44C4 Default gateway: 209.165.202.13016 A network administrator is asked to design a new addressing scheme for a corporate network. There are 60 users in the musers in the branch office, 28 users in manufacturing, 12 in the sales office, and 4 users in the research office. Which VLSM scheme that uses the 192.168.88.0/24 network will fulfill the requirements while wasting the fewest addresses?192.168.88.0/26 main192.168.88.64/26 manufacturing192.168.88.96/27 sales192.168.88.128/28 research192.168.88.0/26 main192.168.88.128/27 manufacturing192.168.88.160/28 sales192.168.88.176/29 research192.168.88.0/27 main192.168.88.64/28 manufacturing192.168.88.80/29 sales192.168.88.88/30 research192.168.88.0/27 main192.168.88.80/28 manufacturing192.168.88.96/29 sales192.168.88.104/30 research17Which physical connector type is used for a serial V.35 connection to the CSU/DSU?18Refer to the exhibit. Which two facts can be determined about the topology? (Choose two.)Four collision domains are present.One logical network is represented.Two broadcast domains are present.Three networks are needed.Three logical address ranges are required.19What are three characteristics of CSMA/CD? (Choose three.)It monitors the media for presence of a data signal.After detecting a collision, hosts can resume transmission after a random timer has expired.A jam signal is used to ensure that all hosts are aware that a collision has occurred.Devices can be configured with a higher transmission priority.Data is transmitted only when the data signal is present.It uses a token system to avoid collisions.20Refer to the exhibit. The serial interface of the router was configured with the use of the commands that are shown. The rou ping the router that is directly connected to interface serial 0/0/0. What should the network technician do to solve this probleConfigure the description at interface serial 0/0/0.Configure an IP address on interface serial 0/0/0.Remove the no shutdown command at interface serial 0/0/0Reboot the router.21Which OSI layer uses the header information to reassemble the data segments into streams?application layernetwork layerpresentation layersession layertransport layer22Refer to the exhibit. The NAT functionality of the router is enabled to provide Internet access to the PC. However, the PC is access the Internet. Which IP address should be changed to 209.165.201.1 to enable the PC to access the Internet?192.168.1.191192.168.1.101192.168.1.1192.168.1.25423Refer to the exhibit. A technician uses the nslookup command on the PC and views the output that is displayed in the exhib IP address of the primary domain name server used by the host?10.10.10.32192.168.1.5192.168.1.99192.168.2.10024Which memory contents will change as a result of using the Router# erase startup-config command on a router?RAMROMflashNVRAM25While configuring a router, a network technician wants to name the router. Which prompt should the technician see when e hostname command?Router>Router#Router(config)#Router(config-line)#26Refer to the exhibit. The PC, the routing table of which is displayed, is configured correctly. To which network device or inte IP address 192.168.1.254 belong?PCswitchrouter interface fa0/0router interface fa0/127Refer to the exhibit. A network administrator is troubleshooting a link that is down between Router1 and Router2. To correc which wire pairs need to be switched on one of the Ethernet cable ends?pair 1 and pair 2pair 1 and pair 3pair 2 and pair 3pair 2 and pair 428Refer to the exhibit. A PC is connected to a network. Which action will verify that the PC can communicate with its default gUse the ping 127.0.0.1 command.Use the ipconfig command.Use the ipconfig/all command.Use the ping 10.0.0.254 command.29Refer to the exhibit. Host B was powered off. What change will occur in the MAC table of the switch?The table will remain unaffected.The switch will remove the MAC address at Fa0/19.The switch will retain the MAC address until host B is powered on again.The switch will rebuild the MAC table by assigning the FFFF.FFFF.FFFF address to port Fa0/19.30What information is contained in the header of Layer 3 to help data delivery?port numberdevice physical addressdestination host logical addressvirtual connection identifier31 A network technician is tasked with setting up a network for six users, but the users should be able to use their accounts toany of the six computers. What type of network should be used?workgroupP2P applicationspeer-to-peer networkclient-server network32Refer to the exhibit. A web browser is running on host PC1 with an IP address 10.10.2.2/24. A dynamic port number of 4915 to the browser. The browser sends a request for a web page to the web server with an IP address 192.168.1.254/24. Which true?The session is established using TCP, and the socket number for the web server is 192.168.1.254: 80.The session is established using TCP, and the socket number for the web server is 192.168.1.254: 49152.The session is established using UDP, and the socket number for the web server is 192.168.1.254: 80.The session is established using UDP, and the socket number for the web server is 192.168.1.254: 49152.33Refer to the exhibit. An administrator on PC1 wants to view some HTML code from a web page housed on the web server. application will allow this request to be started?34Refer to the exhibit. What is required on host A for a network technician to create the initial configuration on Router1?an FTP clienta Telnet clienta terminal emulation programa web browser35What are two characteristics of the data link layer? (Choose two.)It segments and reorders the data.It exchanges the frames between nodes.It defines the method by which network devices place data onto the media.It manages the transfer of data between the processes that run on each host.It retrieves signals from the media and restores them to their bit representations.36 A network administrator wants to restrict access to the router privileged EXEC mode. Which password should the administrenableauxconsoleVTY37Which three IPv4 addresses represent a broadcast for a subnet? (Choose three.)172.16.4.63 /26172.16.4.129 /26172.16.4.191 /26172.16.4.51 /27172.16.4.95 /27172.16.4.221 /2738Refer to the exhibit. Host X is unable to communicate with host Y. Which command can be run at host X to determine which device is responsible for this failure?telnet 192.168.1.1ping 192.168.1.1ftp 192.168.1.1tracert 192.168.1.139Refer to the exhibit. Which option shows the correct topology given the configuration of Router1?40If an administrator wished to return a router to the default state, what additional step must be taken after issuing the comma start-up config?Reload the device.Issue the command copy running-config start-up config.Perform a show running-config to verify that the file was removed.Enter the interface commands to allow the device to connect to the network.41By using the ipconfig command, a network administrator determines that a workstation has the address 192.168.3.38 with the subnet mask. To what network does the workstation belong?192.168.3.8192.168.3.16192.168.3.24192.168.3.3242Which statement is true about router hostnames?A hostname should be unique on each router.A router hostname cannot contain capital letters.A router hostname is configured in privileged executive mode.A router hostname must be created before any other configurations can be added to the device.43 A user types the enable command. What task can be performed at the privileged EXEC mode?Configure the device.Configure individual interfaces.Configure individual terminal lines.Issue show and debug commands.44Refer to the exhibit. Which logical topology describes the exhibited network?starringpoint-to-pointmulti-access45Refer to the exhibit. A user wants to access the Internet from the PC. A part of the running configuration of the router is sho default gateway IP address should be configured at the PC to enable this access?10.1.192.110.1.192.210.1.192.54192.31.7.146Which statement is true about the ICMP protocol?It is an application layer protocol.It is designed to make IP a reliable protocol.It is often filtered out of networks for security purposes.If a host does not respond to an ICMP echo request, the host is not functioning.47Refer to the exhibit. At which OSI layer is serial interface 0/0/1 experiencing problems?Layer 1Layer 2Layer 3Layer 448Refer to the exhibit. The host was disconnected from switch 2 and connected to switch 1. Which combination of IP address, and default gateway should be assigned to this host to allow it to function in the network?IP address: 10.10.9.37 Subnet mask: 255.255.255.240 Default gateway: 10.10.9.35IP address: 10.10.9.37 Subnet mask: 255.255.255.224 Default gateway: 10.10.9.35IP address: 10.10.9.29 Subnet mask: 255.255.255.248 Default gateway: 10.10.9.35IP address: 10.10.9.32 Subnet mask: 255.255.255.224 Default gateway: 10.10.9.35IP address: 10.10.9.37 Subnet mask: 255.255.255.224 Default gateway: 196.1.105.6IP address: 10.10.9.63 Subnet mask: 255.255.255.224 Default gateway: 10.10.9.3549Refer to the exhibit. The diagram represents the process of sending email between clients. Select the list below that correc the component or protocol used at each numbered stage of the diagram.1.MUA2.MDA3.MTA4.SMTP5.MTA6.POP7.MDA8.MUA1.MUA2.POP3.MDA4.SMTP5.MTA6.MDA7.SMTP8.MUA1.MUA2.POP3.SMTP4.MDA5.MTA6.SMTP7.POP8.MUA1.MDA2.SMTP3.MTA4.SMTP5.MTA6.MUA7.POP8.MDA1.MUA2.SMTP3.MTA4.SMTP5.MTA6.MDA7.POP8.MUA50What is the Cisco IOS?system software for Cisco devicesRead Only Memory in Cisco devicesnon-volatile storage for device configurationsan initial operating system that is used for boot functions（注：文档可能无法思考全面，请浏览后下载，供参考。
思科认证CCNA基础知识之IP地址和子网掩码
思科认证CCNA基础知识之IP地址和子网掩码一、为什么要使用IP地址？一个IP地址是用来标识网络中的一个通信实体，比如一台主机，或者是路由器的某一个端口。
而在基于IP协议网络中传输的数据包，也都必须使用IP地址来进行标识，如同我们写一封信，要标明收信人的通信地址和发信人的地址，而邮政工作人员则通过该地址来决定邮件的去向。
同样的过程也发生在计算机网络里，每个被传输的数据包也要包括的一个源IP地址和一个目的IP地址，当该数据包在网络中进行传输时，这两个地址要保持不变，以确保网络设备总是能根据确定的IP地址，将数据包从源通信实体送往指定的目的通信实体。
目前，IP地址使用32位二进制地址格式，为方便记忆，通常使用以点号划分的十进制来表示，如：202.112.14.1。
一个IP地址主要由两部分组成：一部分是用于标识该地址所从属的网络号；另一部分用于指明该网络上某个特定主机的主机号。
为了给不同规模的网络提供必要的灵活性，IP地址的设计者将IP地址空间划分为五个不同的地址类别，如下表所示，其中A,B,C三类最为常用：A类0－127 0 8位24位B类128－191 10 16位16位C类192－223 110 24位8位D类224－239 1110 组播地址E类240－255 1111 保留试验使用网络号由因特网权力机构分配，目的是为了保证网络地址的全球唯一性。
主机地址由各个网络的管理员统一分配。
因此，网络地址的唯一性与网络内主机地址的唯一性确保了IP 地址的全球唯一性。
二、划分子网为了提高IP地址的使用效率，可将一个网络划分为子网：采用借位的方式，从主机位最高位开始借位变为新的子网位，所剩余的部分则仍为主机位。
这使得IP地址的结构分为三部分：网络位、子网位和主机位。
引入子网概念后，网络位加上子网位才能全局唯一地标识一个网络。
把所有的网络位用1来标识，主机位用0来标识，就得到了子网掩码。
如下图所示的子网掩码转换为十进制之后为：255.255.255.224子网编址使得IP地址具有一定的内部层次结构，这种层次结构便于IP地址分配和管理。