sybex ccna fast pass 3rd edition 2007 phần 9 pdf

374 Chapter 8  Implement and verify WAN links 1d16h: Se0/0 CHAP: O RESPONSE id 208 len 27 from "Pod1R1" 1d16h: Se0/0 CHAP: I RESPONSE id 219 len 27 from "Pod1R2" 1d16h: Se0/0 CHAP: O SUCCESS id 219 len 4 1d16h: Se0/0 CHAP: I SUCCESS id 208 len 4 But if you have the username wrong, as we did previously in the PPP authentication failure example back in Figure 14.11, the output would look something like this: 1d16h: Se0/0 PPP: Using default call direction 1d16h: Se0/0 PPP: Treating connection as a dedicated line 1d16h: %SYS-5-CONFIG_I: Configured from console by console 1d16h: Se0/0 CHAP: O CHALLENGE id 220 len 27 from "Pod1R1" 1d16h: Se0/0 CHAP: I CHALLENGE id 209 len 27 from "Pod1R2" 1d16h: Se0/0 CHAP: O RESPONSE id 209 len 27 from "Pod1R1" 1d16h: Se0/0 CHAP: I RESPONSE id 220 len 27 from "Pod1R2" 1d16h: Se0/0 CHAP: O FAILURE id 220 len 25 msg is "MD/DES compare failed" PPP with CHAP authentication is a three-way authentication, and if the username and passwords are not configured exactly the way they should be, then the authentication will fail and the link will be down. Exam Objectives Remember the PPP Data Link layer protocols. The three Data Link layer protocols are: Network Control Protocol (NCP), which defines the Network layer protocols; Link Control Protocol (LCP), a method of establishing, configuring, maintaining, and terminating the point-to-point connection; and High-Level Data Link Control (HDLC), the MAC layer pro- tocol that encapsulates the packets. 85711.book Page 374 Thursday, September 27, 2007 10:35 AM Review Questions 375 Review Questions 1. Which command will display the CHAP authentication process as it occurs between two routers in the network? A. show chap authentication B. show interface serial 0 C. debug ppp authentication D. debug chap authentication 2. Suppose that you have a customer who has a central HQ and six branch offices. They antici- pate adding six more branches in the near future. They wish to implement a WAN technology that will allow the branches to economically connect to HQ and you have no free ports on the HQ router. Which of the following would you recommend? A. PPP B. HDLC C. Frame Relay D. ISDN 3. How should a router that is being used in a Frame Relay network be configured to keep split horizon issues from preventing routing updates? A. Configure a separate subinterface for each PVC with a unique DLCI and subnet assigned to the subinterface. B. Configure each Frame Relay circuit as a point-to-point line to support multicast and broadcast traffic. C. Configure many subinterfaces in the same subnet. D. Configure a single subinterface to establish multiple PVC connections to multiple remote router interfaces. 4. Which encapsulations can be configured on a serial interface? (Choose three.) A. Ethernet B. Token Ring C. HDLC D. Frame Relay E. PPP 5. The Acme Corporation is implementing dial-up services to enable remote-office employees to connect to the local network. The company uses multiple routed protocols, needs authentica- tion of users connecting to the network, and since some calls will be long distance, needs call- back support. Which of the following protocols is the best choice for these remote services? A. 802.1 B. Frame Relay C. HDLC D. PPP E. PAP 85711.book Page 375 Thursday, September 27, 2007 10:35 AM 376 Chapter 8  Implement and verify WAN links 6. Which WAN encapsulations can be configured on an asynchronous serial connection? (Choose two.) A. PPP B. ATM C. HDLC D. SDLC E. Frame Relay 7. Why won’t the serial link between the Corp router and the Remote router come up? Corp#sh int s0/0 Serial0/0 is up, line protocol is down Hardware is PowerQUICC Serial Internet address is 10.0.1.1/24 MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 254/255, txload 1/255, rxload 1/255 Encapsulation PPP, loopback not set Remote#sh int s0/0 Serial0/0 is up, line protocol is down Hardware is PowerQUICC Serial Internet address is 10.0.1.2/24 MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 254/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set A. The serial cable is faulty. B. The IP addresses are not in the same subnet. C. The subnet masks are not correct. D. The keepalive settings are not correct. E. The layer 2 frame types are not compatible. 8. A remote site has just been connected to the central office. However, remote users cannot access applications at the central office. The remote router can be pinged from the central office router. After reviewing the command output shown below, which do you think is the most likely reason for the problem? Central#show running-config ! interface Serial0 ip address 10.0.8.1 255.255.248.0 encapsulation frame-relay frame-relay map ip 10.0.15.2 200 ! Router rip Network 10.0.0.0 85711.book Page 376 Thursday, September 27, 2007 10:35 AM Review Questions 377 Remote#show running-config ! interface Serial0 ip address 10.0.15.2 255.255.248.0 encapsulation frame-relay frame-relay map ip 10.0.8.1 100 ! Router rip Network 10.0.0.0 A. The Frame Relay PVC is down. B. The IP addressing on the Central/Remote router link is incorrect. C. RIP routing information is not being forwarded. D. Frame Relay Inverse ARP is not properly configured. 9. Which of the following describes an industry-wide standard suite of protocols and algorithms that allows for secure data transmission over an IP-based network that functions at the layer 3 Network layer of the OSI model? A. HDLC B. Cable C. VPN D. IPSec E. xDSL 10. Which of the following describes the creation of private networks across the Internet, enabling privacy and tunneling of non-TCP/IP protocols? A. HDLC B. Cable C. VPN D. IPSec E. xDSL 85711.book Page 377 Thursday, September 27, 2007 10:35 AM 378 Chapter 8  Implement and verify WAN links Answers to Review Questions 1. C. The command debug ppp authentication will show you the authentication process that PPP uses between point-to-point connections. 2. C. The key is “there are no free ports” on your router. Only Frame Relay can provide a con- nection to multiple locations with one interface, and in an economical manner no less. 3. A. If you have a serial port configured with multiple DLCIs connected to multiple remote sites, split horizon rules stop route updates received on an interface from being sent out the same interface. By creating subinterfaces for each PVC, you can avoid the split horizon issues when using Frame Relay. 4. C, D, E. Ethernet and Token Ring are LAN technologies and cannot be configured on a serial interface. PPP, HDLC, and Frame Relay are layer 2 WAN technologies that are typically con- figured on a serial interface. 5. D. PPP is your only option, as HDLC and Frame Relay do not support these types of business requirements. PPP provides dynamic addressing, authentication using PAP or CHAP, and call- back services. 6. A, B. Please do not freak out because ATM is an answer to this question. ATM is not covered in depth on the CCNA exam. PPP is mostly used for dial-up (async) services, but ATM could be used as well, although it typically is not used anymore, since PPP is so efficient. 7. E. This is an easy question because the Remote router is using the default HDLC serial encap- sulation and the Corp router is using the PPP serial encapsulation. You should go to the Remote router and set that encapsulation to PPP or change the Corp router back to the default of HDLC. 8. C. Even though the IP addresses don’t look correct, they are in the same subnet, so answer B is not correct. The question states that you can ping the other side, so the PVC must be up— answer A can’t be correct. You cannot configure IARP, so only answer C can be correct. Since a Frame Relay network is a non-broadcast multi-access network by default, broadcasts such as RIP updates cannot be sent across the PVC unless you use the broadcast statement at the end of the frame-relay map command. 9. D. IPSec is an industry-wide standard suite of protocols and algorithms that allows for secure data transmission over an IP-based network that functions at the layer 3 Network layer of the OSI model. 10. C. A virtual private network (VPN) allows the creation of private networks across the Internet, enabling privacy and tunneling of non-TCP/IP protocols. A VPN can be set up across any type of link. 85711.book Page 378 Thursday, September 27, 2007 10:35 AM Appendix A About the Companion CD IN THIS APPENDIX:  What you’ll find on the CD  System requirements  Using the CD  Troubleshooting 85711bapp01.fm Page 379 Thursday, September 27, 2007 11:34 AM What You’ll Find on the CD The following sections are arranged by category and provide a summary of the software and other goodies you’ll find on the CD. If you need help with installing the items provided on the CD, refer to the installation instructions in the "Using the CD" section of this appendix. Some programs on the CD might fall into one of these categories: Shareware programs are fully functional, free, trial versions of copyrighted programs. If you like particular programs, register with their authors for a nominal fee and receive licenses, enhanced versions, and technical support. Freeware programs are free, copyrighted games, applications, and utilities. You can copy them to as many computers as you like—for free—but they offer no technical support. GNU software is governed by its own license, which is included inside the folder of the GNU software. There are no restrictions on distribution of GNU software. See the GNU license at the root of the CD for more details. Trial, demo, or evaluation versions of software are usually limited either by time or func- tionality (such as not letting you save a project after you create it). Sybex Test Engine For Windows and Mac The CD contains the Sybex Test Engine, which includes all of the Assessment Test and Chapter Review questions in electronic format, as well as two bonus exams located only on the CD. PDF of Glossary of Terms For Windows and Mac We have included an electronic version of the a Glossary of Terms in .pdf format. You can view the electronic version of the Glossary with Adobe Reader. Adobe Reader For Windows and Mac 85711bapp01.fm Page 380 Thursday, September 27, 2007 11:34 AM Using the CD 381 We’ve also included a copy of Adobe Reader, so you can view PDF files that accompany the book’s content. For more information on Adobe Reader or to check for a newer version, visit Adobe's website at http://www.adobe.com/products/reader/ . Electronic Flashcards For PC, Pocket PC and Palm These handy electronic flashcards are just what they sound like. One side contains a ques- tion or fill in the blank, and the other side shows the answer. System Requirements Make sure that your computer meets the minimum system requirements shown in the following list. If your computer doesn't match up to most of these requirements, you may have problems using the software and files on the companion CD. For the latest and greatest information, please refer to the ReadMe file located at the root of the CD-ROM.  A PC running Microsoft Windows 98, Windows 2000, Windows NT4 (with SP4 or later), Windows Me, Windows XP, or Windows Vista.  An Internet connection  A CD-ROM drive Using the CD To install the items from the CD to your hard drive, follow these steps. 1. Insert the CD into your computer’s CD-ROM drive. The license agreement appears. Windows users: The interface won't launch if you have autorun disabled. In that case, click Start  Run (for Windows Vista, Start  All Programs  Acces- sories  Run). In the dialog box that appears, type D:\Start.exe . (Replace D with the proper letter if your CD drive uses a different letter. If you don't know the letter, see how your CD drive is listed under My Computer.) Click OK. 2. Read through the license agreement, and then click the Accept button if you want to use the CD. The CD interface appears. The interface allows you to access the content with just one or two clicks. 85711bapp01.fm Page 381 Thursday, September 27, 2007 11:34 AM 382 Appendix A  About the Companion CD Troubleshooting Wiley has attempted to provide programs that work on most computers with the minimum system requirements. Alas, your computer may differ, and some programs may not work properly for some reason. The two likeliest problems are that you don’t have enough memory (RAM) for the programs you want to use, or you have other programs running that are affecting installation or running of a program. If you get an error message such as “Not enough memory” or “Setup cannot con- tinue,” try one or more of the following suggestions and then try using the software again: Turn off any antivirus software running on your computer. Installation programs some- times mimic virus activity and may make your computer incorrectly believe that it’s being infected by a virus. Close all running programs. The more programs you have running, the less memory is available to other programs. Installation programs typically update files and programs; so if you keep other programs running, installation may not work properly. Have your local computer store add more RAM to your computer. This is, admittedly, a drastic and somewhat expensive step. However, adding more memory can really help the speed of your computer and allow more programs to run at the same time. Customer Care If you have trouble with the book’s companion CD-ROM, please call the Wiley Product Technical Support phone number at (800) 762-2974. Outside the United States, call +1(317) 572-3994. You can also contact Wiley Product Technical Support at http://sybex.custhelp.com . John Wiley & Sons will provide technical support only for installation and other general quality control items. For technical support on the applications themselves, consult the program’s vendor or author. To place additional orders or to request information about other Wiley products, please call (877) 762-2974. 85711bapp01.fm Page 382 Thursday, September 27, 2007 11:34 AM Glossary 85711.book Page 383 Tuesday, September 25, 2007 7:33 PM [...]... connections defined by Phase I LAN emulation; a bidirectional virtual control connection (VCC) established in ATM by an LEC to an LES See also: control distribute VCC 85711.book Page 399 Tuesday, September 25, 2007 7:33 PM Glossary 399 control distribute VCC One of two control connections defined by Phase 1 LAN emulation; a unidirectional virtual control connection (VCC) set up in ATM from an LES to an LEC... certain set of the most important requirements Fast Ethernet Any Ethernet specification with a speed of 100Mbps Fast Ethernet is 10 times faster than 10BaseT while retaining qualities such as MAC mechanisms, MTU, and frame format These similarities make it possible for existing 10BaseT applications and management tools to be used on Fast Ethernet networks Fast Ethernet is based on an extension of IEEE... to receive/ store sporadic deliveries of data bursts, usually received from faster devices, compensating for the variations in processing speed Incoming information is stored until everything is received prior to sending data on Also known as an “information buffer.” 85711.book Page 394 Tuesday, September 25, 2007 7:33 PM 394 Glossary bursting Some technologies, including ATM and Frame Relay, are considered... proprietary protocol developed by Cisco The router uses CGMP to send multicast membership commands to Catalyst switches 85711.book Page 396 Tuesday, September 25, 2007 7:33 PM 396 Glossary channelized E1 Operating at 2.048Mpbs, an access link that is sectioned into 29 B channels and one D channel, supporting DDR, Frame Relay, and X.25 Compare with: channelized T1 channelized T1 Operating at 1.544Mbps,... tunnel 85711.book Page 390 Tuesday, September 25, 2007 7:33 PM 390 Glossary AURP tunnel A connection made in an AURP WAN that acts as a single, virtual link between AppleTalk internetworks separated physically by a foreign network such as a TCP/IP network See also: AURP authentication The first component in the AAA model Users are typically authenticated via a username and password, which are used... TCP port 1 79 is used Also known as “BGP peers.” BGP peers See: BGP neighbors BGP speaker A router that advertises its prefixes or routes bidirectional shared tree A method of shared tree multicast forwarding This method allows group members to receive data from the source or the RP, whichever is closer See also: RP (rendezvous point) 85711.book Page 392 Tuesday, September 25, 2007 7:33 PM 392 Glossary... IEEE 802.3u standard, 100BaseT is the Fast Ethernet specification of 100Mbps baseband that uses UTP wiring 100BaseT sends link pulses (containing more information than those used in 10BaseT) over the network when no traffic is present See also: 10BaseT, Fast Ethernet, and IEEE 802.3 100BaseTX Based on the IEEE 802.3u standard, 100BaseTX is the 100Mbps baseband Fast Ethernet specification that uses... originating port; it specifies in which order calls will be reconnected Additionally, call priority identifies which calls are allowed during a bandwidth reservation 85711.book Page 395 Tuesday, September 25, 2007 7:33 PM Glossary 395 call setup Handshaking scheme that defines how a source and destination device will establish a call to each other call setup time The length of time necessary to effect a switched... between the highest and lowest frequencies employed by network signals More commonly, it refers to the rated throughput capacity of a network protocol or medium 85711.book Page 391 Tuesday, September 25, 2007 7:33 PM Glossary 391 bandwidth on demand (BoD) This function allows an additional B channel to be used to increase the amount of bandwidth available for a particular connection baseband A feature... of routers and switches that supplies shared functionality, scalability, and security for all products under its CiscoFusion architecture See also: CiscoFusion 85711.book Page 397 Tuesday, September 25, 2007 7:33 PM Glossary 397 CiscoView GUI-based management software for Cisco networking devices, enabling dynamic status, statistics, and comprehensive configuration information Displays a physical view . Support phone number at (800) 762- 297 4. Outside the United States, call +1(317) 572- 399 4. You can also contact Wiley Product Technical Support at http:/ /sybex. custhelp.com . John Wiley &. products, please call (877) 762- 297 4. 85711bapp01.fm Page 382 Thursday, September 27, 2007 11:34 AM Glossary 85711.book Page 383 Tuesday, September 25, 2007 7:33 PM 384 Glossary 10BaseT . tables for the complete AppleTalk WAN. See also: AURP tunnel. 85711.book Page 3 89 Tuesday, September 25, 2007 7:33 PM 390 Glossary AURP tunnel A connection made in an AURP WAN that acts as a single,