CCNA2_7_english

培训大讲堂官方YY 频道：3660mCCNA题库考试代号：640-802考试时间: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：http：//bbs。

hh010。

com/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：/forum—261-1.html1000 G视频教程免费下载：http：//bbs.hh010。

com/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，以后不会再出V105 V106 V108等等CCNA 最新题库/最新战报发布区：http：//bbs.hh010。

com/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http：// CCNA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。

2012。

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，哪种提示表明你在特权模式？)A。

CCNA专业英文词汇全集CCNA为思科最基础的入门认证，其中，考试偏重网络概念和理论，对于初学者来说，不少专业英文术语难以理解，导致学员学习进度维难。

CISCO系列认证的原版教材，专业词汇出现频率积高，考生只要熟悉本文，相信学习起来一定事半功倍^-^10BaseT-----原始IEEE802.3标准的一部分，1OBaseT是1OMb/s基带以太网规范，它使用两对双绞电缆(3类、4类或5类)，一对用于发送数据另一对用于接收数据。

1OBaseT每段的距离限制约为100米。

参见Ethernet和IEEE 802.3。

1OOBaseT-----基于IEEE 802.3U标准，1OOBaseT是使用UTP接线的基带快速以太网规范。

当没有通信量出现时。

1OOBaseT在网络上发送链接脉冲(比1OBaseT中使用的包含更多信息)。

参见10BaseT、Fast Ethernet和IEEE 802.3。

100BaseTX-----基于IEEE 802.3U标准，100BaseTX是使用两对UTP或STP 接线的10OMb/S基带快速以太网规范。

第一对线接收数据;第二对线发送数据。

为确保正确的信号定时，一个100BaseTX网段不能超过100米长。

A&B bit signaling (A和B比特信令)-----用于T-1传输设备，有时称为"第24信道信令"。

在这一方案中，每个T-1于信道使用每个第六帧的一个比特来发送监控信令信息。

AAA-----身份验证(Authentication)、授权(Authorization)和统计(Accounting)Cisco开发的一个提供网络安全的系统。

奏见authentication。

authorization和accountingAAL ATM适应层-----数据链路层的一个与服务有关的子层，数据链路层从其他应用程序接受数据并将其带人ATM层的48字节有效负载段中。

Exam Viewer - ENetwork Final Exam - CCNA Exploration: Network Fundamentals (Version 4.0)(FormO-1a)Below you will find the assessment items as presented on the exam as well as the scoring rules associated with the item.Cisco Networking Academy content is copyrighted and the unauthorized posting, distribution or sharing of this exam content is prohibited.1When must a router serial interface be configured with the clock rate command?when the interface is functioning as a DTE devicewhen the interface timers have been clearedwhen the connected DTE device is shut downwhen the interface is functioning as a DCE deviceObservable DescriptionMaxValue1correctnessof response2 points for Option 40 points for any other option22Refer to the exhibit. A network technician is trying to determine the correct IP address configuration for Host AWhat is a valid configuration for Host A?IP address: 192.168.100.19; Subnet Mask: 255.255.255.248; Default Gateway: 192.16.1.2IP address: 192.168.100.20; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.100.17IP address: 192.168.100.21; Subnet Mask: 255.255.255.248; Default Gateway: 192.168.100.18IP address: 192.168.100.22; Subnet Mask: 255.255.255.240; Default Gateway: 10.1.1.5IP address: 192.168.100.30; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.1.1IP address: 192.168.100.31; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.100.18 Observable Description Max Value1correctnessof response2 points for Option 20 points for any other option23Refer to the exhibit. What function does router RT_A need to provide to allow Internet access for hosts in thisnetwork?address translationDHCP servicesftpdweb serverObservable Description Max Value1correctnessof response2 points for Option 10 points for any other option24Refer to the exhibit. Host A attempts to establish a TCP/IP session with host C. During this attempt, a frame wa captured with the source MAC address 0050.7320.D632 and the destination MAC address 0030.8517.44C4. The packet inside the captured frame has an IP source address 192.168.7.5, and the destination IP address is 192.168.219.24. At which point in the network was this packet captured?leaving host Aleaving ATLleaving Dallasleaving NYCObservable Description MaxValue1correctnessof response2 points for Option 30 points for any other option25Which range of port numbers are reserved for services that are commonly used by applications that run on servers?0 to 2550 to 10231024 to 4915149152 to 65535Observable Description Max Value1correctness ofresponse2 points for Option 20 points for any other2option6Which prompt represents the appropriate mode used for the copy running-config startup-config command ?Switch-6J>Switch-6J#Switch-6J(config)#Switch-6J(config-if)#Switch-6J(config-line)#Observable Description Max Value1correctness ofresponse2 points for Option 20 points for any otheroption27Refer to the exhibit. A technician is working on a network problem that requires verification of the router LANinterface. What address should be pinged from this host to confirm that the router interface is operational?127.0.0.1192.168.64.196192.168.254.1192.168.254.9192.168.254.254Observable Description Max Value1correctnessof response2 points for Option 30 points for any other option28Refer to the exhibit. Host A is unable to reach host B on the remote network. A technician attempted to pingthe local gateway and the ping was successful. To verify the host configuration, the technician issued theipconfig command. What is the likely cause of the problem?The local NIC is incorrectly configured.The subnet mask on host A is incorrectly configured.The IP address on host A is incorrectly configured.The default gateway on host A is incorrectly configured.Observable Description Max Value1correctnessof response2 points for Option 40 points for any other option29An organization has been assigned network ID 10.10.128.0 and subnet mask 255.255.224.0. Which IP address range can be used for this organization?10.10.128.0 to 10.10.160.25510.10.128.0 to 10.10.159.25510.10.128.0 to 10.10.192.25510.10.128.0 to 10.10.0.15910.10.128.0 to 10.10.159.0Observable Description Max Value1correctness ofresponse2 points for Option 20 points for any otheroption210Refer to the exhibit. An employee wants to access the organization intranet from home. Which intermediarydevice should be used to connect the organization intranet to the Internet to enable this access?hubswitchrouterwireless access pointObservable Description Max Value1correctnessof response2 points for Option 30 points for any other option211Which OSI layer manages data segments?application layerpresentation layersession layertransport layerObservable Description Max Value1correctness ofresponse2 points for Option 40 points for any otheroption212Which two types of media can provide bandwidth up to 1 Gb/s? (Choose two.)10 BASE-T100 BASE-T100 BASE-FX1000 BASE-TX1000 BASE-SXObservable DescriptionMaxValue1correctness ofresponseOption 4 and Option 5 are correct.1 point for each correct option.0 points if more options are selected thanrequired.213To enhance security in a network, the network administrator uses these commands:Router(config)# line console 0Router(config-line)# password j1mdi2Router(config-line)# loginWhat two conclusions are evident from these commands? (Choose two.)Users who attempt to connect to the console port of the router must enter a password.The entries permit access through the console by the use of j1mdi2 as the password.The entries eliminate the need for authentication.Access through the console will be denied because the console configuration is incomplete.The entries prevent passwords from being displayed as plain text.Observable DescriptionMaxValue1correctness ofresponseOption 1 and Option 2 are correct.1 point for each correct option.0 points if more options are selected thanrequired.214Refer to the exhibit. RouterB is configured properly. The Ethernet interface Fa0/0 of RouterA is configuredwith the use of the commands that are shown. However, a ping from the Fa0/0 interface of RouterA to theFa0/0 interface of RouterB is unsuccessful. What action should be taken on RouterA to solve this problem?Use the description command on the FastEthernet interface Fa0/0.Configure the clock rate of the FastEthernet interface Fa0/0.Use the no shutdown command on the FastEthernet interface Fa0/0.Reboot the router.Observable Description Max Value1correctness ofresponse2 points for Option 30 points for any other option215Refer to the exhibit. When host A sends a frame addressed for host D, which hosts will receive the frame?only host Donly hosts A and Donly hosts B, C, and Dall hostsObservable Description Max Value1correctnessof response2 points for Option 10 points for any other option216Refer to the exhibit. Communication for hosts X and Y is restricted to the local network. What is the reasonfor this?Host X is assigned a network address.Host Y is assigned a multicast address.Host X and host Y belong to different networks.The gateway addresses are broadcast addresses.Observable Description Max Value1correctness ofresponse2 points for Option 40 points for any other option217 A user enters /web1.htm in the address line of a browser. Which statement is trueabout this transaction?The "http" portion indicates the protocol that is being used.The "web1.htm" portion is the specific service name.The retrieved web page will be displayed in URL code.The "" is the name of the web page file that is called.Observable Description Max Value1correctness ofresponse2 points for Option 10 points for any other option218The tracert 10.1.3.2 command was issued on computer A. Computer A can ping other addresses on the local Computer A sent the first ICMP packet toward computer B with a TTL value of 1. A protocol analyzer that was on computer B showed that the packet never reached its destination. Why did the packet not reach the destinaThere is a TCP/IP problem on computer A.There is a routing loop between R1 and R2.R1 does not have a route for the destination network.The TTL for the packet was decreased to zero by R1.Observable Description MaxValue1correctnessof response2 points for Option 40 points for any other option219 A routing issue has occurred in your internetwork. Which of the following type of devices should beexamined to isolate this error?access pointhosthubrouterswitchObservable Description Max Value1correctness ofresponse2 points for Option 40 points for any otheroption220Which physical component is used to access and perform the initial configuration on a new unconfigured router?Observable DescriptionMax Value1correctness of response 2 points for Option 2 0 points for any other option221What can the user do from the command prompt, Router(config-line)# ?Configure one of the network interfaces.Configure one of the physical or virtual lines.Verify the running configuration on the device.Configure the parameters for one of the routing protocols.ObservableDescriptionMax Value1correctness of response2 points for Option 2 0 points for any other option222Which option shows the PDU that contains the Layer 3 source and destination addressing for a packet?Observable Description Max Value1correctness ofresponse2 points for Option 30 points for any other option223Refer to the exhibit. The ping 127.0.0.1 command is issued on the local host. What do the ping resultsindicate?The local host can send packets on the local network.The TCP/IP stack on the local host operates properly.The local host has full connectivity to the default gateway.The local host has full connectivity to the remote network. Observable Description Max Value1correctnessof response2 points for Option 20 points for any other option224Which topology divides the collision domain and provides full media bandwidth to the hosts in the network?Observable Description Max Value1 correctness of response2 points for Option 30 points for any other option225Refer to the exhibit. Which option correctly identifies the network address, range of host addresses, and thebroadcast address for the network that contains host A?Observable Description Max Value1correctness ofresponse2 points for Option 30 points for any other option226 A technician is setting up a workgroup for six users and wants to allow users to share files without settinup a server. Which application layer protocol will provide for peer-to-peer file sharing in a workgroup?DNSSMBHTTPDHCPObservable Description Max Value1correctness of 2 points for Option 2 2response 0 points for any otheroption27Which router component will have contents erased when the command erase startup-config is issued?flashRAMROMNVRAMObservable Description Max Value1correctness ofresponse2 points for Option 40 points for any otheroption228Refer to the exhibit. Host1 is in the process of setting up a TCP session with Host2. Host1 has sent a SYNmessage to begin session establishment. What happens next?Host1 sends a segment with the ACK flag = 0, SYN flag = 0 to Host2.Host1 sends a segment with the ACK flag = 1, SYN flag = 0 to Host2.Host1 sends a segment with the ACK flag = 1, SYN flag = 1 to Host2.Host2 sends a segment with the ACK flag = 0, SYN flag = 1 to Host1.Host2 sends a segment with the ACK flag = 1, SYN flag = 0 to Host1.Host2 sends a segment with the ACK flag = 1, SYN flag = 1 to Host1.Observable Description Max Value1correctnessof response2 points for Option 60 points for any other option229How many host addresses may be assigned when using the 128.107.0.0 network address with a subnet mask of 255.255.248.0?302562046204840944096Observable Description Max Value1correctness ofresponse2 points for Option 30 points for any otheroption230Refer to the exhibit. Host A is able to access resources on the local LAN but is unable to access anyresources on the Internet. What is the likely cause of this problem?The host subnet mask in incorrect.The network uses private addresses.The host address is a network address.The default gateway is on a different subnet from the host.Observable Description Max Value1correctness ofresponse2 points for Option 40 points for any other option231What is described by the network access layer of the TCP/IP model?rules for packet acknowledgment, error recovery, and sequencingrules for the handoff from the internet layer to the network access protocolsrules for how source and destination hosts exchange data between programsrules for determining which processes can be used to route messages through an internetwork Observable DescriptionMax Value1correctness ofresponse2 points for Option 20 points for any otheroption232Which two factors contribute to the increased throughput when all nodes of a LAN are connected to a switch instead of a hub? (Choose two.)full-duplex operationcollision-free environmentlogical bus media accessbroadcast-free environmentpoint-to-multipoint topologyObservable DescriptionMaxValue1correctness ofresponseOption 1 and Option 2 are correct.1 point for each correct option.0 points if more options are selected thanrequired.233Which application layer protocol allows administrators to log into a server from remote locations and control a server as though logged in locally?DNSFTPDHCPSMTPTelnetObservable DescriptionMax Value1correctness ofresponse2 points for Option 50 points for any otheroption234 A network technician has made a UTP cable that is terminated as T568A on one end and T568B on theopposite end. What type of cable has been constructed?patchconsolecrossoverstraight-throughObservable Description Max Value1correctness ofresponse2 points for Option 30 points for any otheroption235Which application belongs to the category of the client/server model?using Telnet to access a routerexchanging information via instant messagingprinting a document to a locally connected printerscanning a document with a directly connected scanner Observable Description Max Value1correctness ofresponse2 points for Option 10 points for any otheroption236Refer to the exhibit. Which two layers of the OSI model describe the same functions as the transport andinternet layers of the TCP/IP model? (Choose two.)application layerpresentation layersession layertransport layernetwork layerdata link layerphysical layerObservable DescriptionMaxValue 1correctness of responseOption 4 and Option 5 are correct. 1 point for each correct option.0 points if more options are selected than required.237What command can be used to troubleshoot domain name resolution issues?getarp -a tracertnslookupObservable DescriptionMax Value1correctness of response 2 points for Option 4 0 points for any other option238Refer to the exhibit. For connecting two routers with an Ethernet crossover cable, which interface should be used?AB C DObservableDescription Max Value1correctness of response 2 points for Option 30 points for any other option239A technician is asked to secure the privileged EXEC mode of a switch by requiring a password. Whichtype of password would require this login and be considered the most secure?consoleenable enable secret VTYObservableDescriptionMax Value1correctness of response 2 points for Option 3 0 points for any other option240Which three addresses belong to the category of public IP addresses? (Choose three.)127.0.0.1196.1.105.6 132.11.9.99 10.0.0.1 172.16.9.10 46.1.1.97ObservableDescriptionMaxValue1correctness of responseOption 2, Option 3, and Option 6 are correct.1 point for each correct option.0 points if more options are selected than required.341A network administrator is configuring several switches for a network. The switches have similar configurations and only minor differences. The administrator wants to save all commands that are issued on the first switch to a text file for editing. Which transfer option should be selected in HyperTerminal?Observable Description MaxValue1correctnessof response2 points for Option 30 points for any other option242Which option represents a point-to-point logical topology diagram?Observable DescriptionMax Value1correctness ofresponse2 points for Option 40 points for any other option243Refer to the exhibit. What two facts can be determined from the session information that is displayed?(Choose two.)The protocol is a connection-oriented protocol.This exchange is part of the three-way handshake.The SYN flag is representing the initial establishment of a session.The destination port indicates that an FTP session has been initiated.The source port does not support communication with the destination port that is listed.Observable DescriptionMax Value1correctness ofresponseOption 1 and Option 2 are correct.1 point for each correct option.0 points if more options are selected thanrequired.244Which communication tool allows real-time collaboration?wikie-mailwebloginstant messagingObservable Description Max Value1correctness ofresponse2 points for Option 40 points for any otheroption245Which prompt is associated with the privileged exec mode?R1>R1#R1(config)#R1(config-router)#Observable Description Max Value1correctness ofresponse2 points for Option 20 points for any otheroption246What is the effect of the command copy running-config tftp?copies the configuration from a remote machine into RAMcopies the configuration from a remote machine into NVRAMcopies the configuration currently in RAM to a remote machinecopies the configuration currently in NVRAM to a remote machine Observable Description Max Value1correctness ofresponse2 points for Option 30 points for any otheroption247Refer to the exhibit. Which type of network design is shown?client/serverwide areadedicated serverpeer-to-peerObservable Description Max Value1correctnessof response2 points for Option 40 points for any other option248Refer to the exhibit. A network administrator remotely accesses the CLI of RouterB from PC1 using Telnet.Which statement is true about this connection?The data is automatically encrypted.A Telnet server process is running on PC1.The connection is made through a VTY session on the router.A GET request was sent to RouterB to retrieve data during this session.Observable Description Max Value1correctnessof response2 points for Option 30 points for any other option249Refer to the exhibit. A network technician wants to connect host A to the console of a Cisco switch to initializethe configuration. What type of cable is required for this connection?straight-through cablecrossover cablerollover cableserial cableObservable Description Max Value1correctness 2 points for Option 3 2of response 0 points for any other option50 A technician makes several changes to the running configuration on a router, but the desired results arenot achieved. The technician issues the reload command. What action will be taken by the router?All changes will be lost and the router will restart immediately.Changes will be saved automatically and the router will restart.The user will be prompted to save changes before the router restarts.The router will detect changes to the running configuration and will reload using the configurationstored in RAM.Observable Description Max Value1correctness ofresponse2 points for Option 30 points for any otheroption2。

思科认证英文全名及中文职称对照Testpassport ccna 题库我想多多少少应该有部分或者大部分人都是说不全思科认证英文全名的，今天就了解到的和日常收集整理的认证资料写进我的博客的时候顺带发一份给大家，主要是思科的部分认证的中英文全称，供大家温习温习。

思科认证英文全名及中文职称对照【思科认证网络工程师】（英文全名Cisco Certified Network Associate，简称CCNA）表示具备基本的和初步的网络知识。

拥有CCNA认证的人士可以为小型网络（不超过100个节点）安装、配置和操作LAN、WAN和拨号接入服务，其中包括但不仅限于下列协议：IP、IGRP、串行、帧中继、IP RIP、VLAN、RIP、以太网和访问列表。

【思科认证设计工程师】（英文全名Cisco Certified Design Associate，简称CCDA）表示在设计思科网络基础设施方面具备基本的或者初步的知识。

拥有CCDA 认证的人士可以为企业和机构设计包含LAN、WAN和拨号接入服务的路由和交换网络基础设施【思科认证高级网络工程师】（英文全名Cisco Certified Network Professional，简称CC NP）表示网络人士具有对从100个节点到超过500 个节点的融合式局域网和广域网进行安装、配置和排障的能力。

获得CCNP认证资格的网络人士拥有丰富的知识和技能，能够管理构成网络核心的路由器和交换机，以及将语音、无线和安全集成到网络之中的边缘应用。

必备条件:有效的CCNA认证资格。

【思科认证语音专家】（英文全名Cisco Certified Voice Professional，简称CCVP）CCVP 认证表示非常精通融合式IP网络的实施、运行、配置和排障。

认证内容侧重于Cis co Systems CallManager、服务质量(QoS)、网关、关守、IP电话、语音应用和思科路由器及Cisco Catalyst交换机上的应用等主题。

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。

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。

CCNA学习指南中文第七版第一章(1)集线器:1个冲突域。

1个广播域。

(2)网桥:2个冲突域。

1个广播域。

(3)交换机:4个冲突域。

1个广播域。

(4)路由器:3个冲突域。

个广播域。

(1) D.作为接收方的主机可使用流量控制(默认情况下，TCP 使用窗口技术)控制发送方。

通过缩小窗口，作为接收方的主机可降低发送方的传输速度，从而避免缓冲区溢出。

(2)D.发送给MAC地址ff:ff:ff:ff:ff:ff的数据是给所有工作站的广播。

(3) C 、D.你并非真的想增大冲突域，但集线器(多端口转发器)可提供这种功能。

(4) D.传输层从上层接收大型数据,将其分割成较小的片段,这些片段称为数据段。

(5) A 、C 、E 、G.路由器提供分组交换、分组过滤、互联网络通信以及路径选择功能。

虽然路由器确实分割或终止冲突域,但这不是路由器的主要功能,因此选项B不正确。

(6) B.路由器运行在第3层,LAN交换机运行在第2 层,以太网集线器运行在第1层。

字处理程序与应用层接口通信,但并非运行在第7层,因此答案为"无"。

(7) C.封装顺序为数据、数据段、分组、帧、比特。

(8) A 、D.分层模型的主要优点是,让应用程序开发人员能够只在分层模型的某一层修改程序的部分功能。

使用OSI 分层模型的优点包括但不限于:将网络通信过程划分成更小、更简单的组件,这有助于组件的开发、设计和故障排除;通过标准化网络组件,让多家厂商能够协作开发。

定义了模型每层执行的功能,从而鼓励了行业标准化。

让不同类型的网络硬件和软件能够彼此通信。

避免对一层的修改影响其他层。

从而避免妨碍开发工作。

(9)A 、D.不同于全双工，半双工以太网运行在一个共享的冲突域中,其有效吞吐量低于全双工模式。

(10)B.在网络中为建立连接添加交换机可缓解LAN拥案,而不会导致LAN拥塞。

(11)C.如果1 台交换机连接了3台计算机,且没有配置VLAN,它将创建1个广播域和3个冲突域。