CCNA试题.docx

1、CCNA试题Thanks for filling out the information request form if you are interested in accelerated CCNA or MCSE programs please visit .(11) List commands to monitor Frame Relay operation on the routerIn the user mode key in the following:Routersho frame ?ip show frame relay IP staticslmi show frame rela

2、y lmi staticsmap show frame relay map tablepvc show frame relay pvc staticsroute show frame relay routetraffic show frame relay protocol statics(12) Identify PPP operations to encapsulate WAN data on CISCO routersPoint to Point Protocol (PPP) is a data link protocol that can be used on asynchronous

3、(dial up) or synchronous ISDN circuits. It uses Link Control Protocol (LCP) to build and maintain data link connections. Some features included in PPP are: Password Authentication Protocol (PAP) and Challenge Handshake Password Authentication Protocol (CHAP). Data compression and multiple protocols

4、such as IP, IPX , AppleTalk DECnet and OSI/CLNS are supported. Encapsulate PPP on the router#int s0#encapsulate ppp(13) State a relevant use and context for ISDN networkingIntegrated Services Digital Network (ISDN) can run on existing telephones lines to provide an end to end digital service for bot

5、h domestic and business uses. ISDN can carry, in addition to voice and data, multimedia as well. ISDN can used as a backup circuit for high speed network links. CISCO routers can be configured to automatically dial up on an ISDN link when the main network link goes down.(14) Identify ISDN protocols,

6、 function groups, reference points and channels ISDN protocols were defined by CCITT (now ITU-T), and there are three protocols that define the complex transmission issues: Protocol specifications beginning with latter E, specify ISDN on the existing telephone network, ie; Analog lines. Protocol spe

7、cifications beginning with letter I, specify concepts, terminology and services. Protocol specifications beginning with letter Q, specify trunk switching and signaling.(15) Describe Ciscos Implementation of ISDN BRIISDN Basic Rate Interface (BRI), service provides two B channels and D channel, which

8、 is also known as 2B+D. B channels operate at 64 kbps and carries user information where D channel operates at 16 kbps and usually carry control and signaling information. D channel signaling protocol spans the OSI reference models, Physical layer, Data link layer and the Network layer. The two 64 k

9、bps lines can be used as a single 128 kbps channel. To place a call on ISDN is similar to placing a call on Plain Old Telephones (POTS). For ISDN network to identify a call placed on its network, you must use directory numbers and Service Profile Identifiers (SPID)s. These two items are given to you

10、 by the service provider. Directory number is a telephone number you will use when you call. The SPID is a number the telephone uses to identify equipment on your ISDN connection. Majority of switches in US are either AT&T 5ESS, 4ESS or Northern Telcom DMS 100. Attaching a CISCO router to ISDN needs

11、 either a Network Termination 1 or an ISDN modem. If router has a BRI interface, (called Terminal End Point 1) then it is ready to be connected to the ISDN network.Router#config tRouter(config)#isdn switch-type basic-dms100Router(config)#int bri0Router(config-if)#encap pppRouter(config-if)#isdn spid

12、 775456721Router(config-if)#ppp authentication chapIOS(16) Log in to a router in user and privilege modeCISCO IOS software has a command interpreter called Exec. Exec has two levels of access: User mode and privilege mode. These two levels serve as for access into the different levels of commands. I

13、n user mode one can only do: Check router status, connecting to remote devices, making temporary changes to terminal settings and viewing basic system information. In the privilege mode you can change the configuration of the router and get detail reports of router status. Test and run debug operati

14、ons. Access global configuration modes. When you first log into a router, press ENTER and you will be in the Exec mode. At the prompt it will ask if you need a password. Router This is the User mode as stated above very little can be done at this level. When you type in Enable: RouterEnable and pres

15、s return it will ask for the password. Once you key in the correct password, your in the privilege mode. Now the prompt will show you Router#. (17) Use the context-sensitive help facilityOne can receive help on any command by typing ? after the command. In the following example: Router# clock ? you

16、typed in clock a space and the question mark, and pressed enter. Reply was as follows: set Set the time and date. Now you want to know what format to enter. So you put another question after the set as follows: Router# clock set ?. Now you will get the format in the reply as follows: hh:mm:ss: Curre

17、nt Time (hh:mm:ss)(18) Use the command history and editing featuresThe user interface comes in with an editing feature to help you type in repetitive commands. One can turn off editing by typing terminal no editing and again turn it on by typing terminal editing. The router keeps the last ten comman

18、ds you entered during your console or terminal session, in a special memory buffer called command history. One can recall commands from the command history buffer and reuse them or modify slightly to save on typing. To see all the commands type the following at the command prompt Router#show history

19、 and press enter. All commands you typed in will be shown. To increase the size of the command history buffer you type the following: Router#terminal history size 100. This will increase the size to 100 lines from the default value. VT 100 terminal emulation gives use of up down and side arrows in a

20、ddition to the other keys as shown below: CTRL+A Move to the beginning of the command line CTRL+E Move to the end of the command line CTRL+F (or right arrow) Move one character forward CTRL+B (or left arrow) Move one character backward CTRL+P (or up arrow) Repeat previous command entry CTRL+N (or do

21、wn arrow) Most recent command recall ESC+B Move backward one word ESC+F Move forward one word(19) Examine router elements (RAM,ROM,CDP,show) CISCO routers use the following type of memory: Random Access Memory (RAM) stores the running configuration when the router is running and it is cleared when s

22、witched off. Also provides cashing, routing tables and packet buffering. The IOS operates from RAM Flash Memory is an electrically erasable, re-programmable ROM that holds the operating system image and microcode. This facilitates the upgrades to the operating system with out replacing the chips on

23、the motherboard. Read Only Memory (ROM) is used by the router to store bootstrap program, operation system software and Power On Self Test (POST). The ROM chips are installed in sockets on the routers motherboard, so that they can be replaced or upgraded. ROM holds the smaller version of IOS and is

24、loaded during power up so the router can boot up. Nonvolatile RAM (NVRAM) This memory does not loose its information when the router is powered down. Stores the systems start up configuration file and the virtual configuration register.Cisco Discovery Protocol (CDP) is Ciscos proprietary protocol th

25、at allows you to access configuration on other routers with a single command. By running Sub Network Access Protocol (SNAP) at the data link layer, two devices running different Network Layer protocols can communicate and learn about each other. These devices include all LAN and some WANs. CDP start

26、s by default on any router version 1.3 earlier and discovers neighboring CISCO routers running CDP by doing a Data Link broadcasts. It does not matter what protocol is running at the network layer. Once CDP has disproved a router, it can then display information about the upper layer protocols, such

27、 as IP and IPX. The router caches the information it receives from its CDP neighbors. Any time a router receives up dated information that a CDP neighbor has changed, it discards the old information in favor of the broadcast.There are many show commands available for the administrator to manage the

28、router. They can be found by typing at the command prompt Router#sh ?.(20) Manage configuration files from the privilege exec mode.When the router is powered up, it does a self-test, then loads the IOS image, and finds the configuration file and loads it. Startup configuration is in NVRAM and the op

29、erating system places it on to the RAM. To manage configuration files you must be in privilege mode. At start up you will be in user mode. To get to the privilege mode do the following: Routerenable, if passwords are enabled then enter them when asked. Now your in privilege mode. Router#. By typing

30、config t you can modify configuration files. Following are commands for starting and saving configurations: Show startup-config Shows the configuration that will loaded when the Router boots. Show running-config Show the configuration that is currently loaded to RAM and is running Erase startup-conf

31、ig This command will erase the configuration in NVRAM and put you in to the initial configuration dialog Reload This command will reload the startup-config toMemory Setup This command starts the initial configuration dialogSoftware version 10.3 and earlier should run the following router commands: S

32、how config Same as show startup-config Write term Same as show running-config Write erase Same as erase startup-config Write mem Same as copy running-config startup config(21) Control router password, identification and bannerThere are five different passwords that is used to secure CISCO routers and they are as follows:Enable secret is a cryptographic password used in version 10.3 and up. It has precedence over the enable password when it exists. O