Table of Contents CCNA for Dummies...........................................................................................................................................1 Overview.................................................................................................................................................1 About the Authors...................................................................................................................................2 Dedication...............................................................................................................................................3 Authors(cid:25) Acknowledgments..................................................................................................................3 Publisher(cid:25)s Acknowledgments..............................................................................................................3 Introduction........................................................................................................................................................5 Overview.................................................................................................................................................5 Why Use This Book?..............................................................................................................................5 Using This Book.....................................................................................................................................6 Part I: The Basics.............................................................................................................................6 Part II: The OSI Reference Model...................................................................................................6 Part III: Routers................................................................................................................................6 Part IV: Network Protocols..............................................................................................................6 Part V: LANs and WANs.................................................................................................................6 Part VI: The Part of Tens.................................................................................................................6 Part VII: Appendixes........................................................................................................................7 What(cid:25)s on the CD............................................................................................................................7 Studying Chapters...................................................................................................................................7 First page..........................................................................................................................................7 Quick Assessment questions............................................................................................................7 Study subjects...................................................................................................................................7 Prep Tests.........................................................................................................................................9 Icons Used in This Book.........................................................................................................................9 Feedback.................................................................................................................................................9 Part I: The Basics.............................................................................................................................................10 Chapter List............................................................................................................................................10 In this part&....................................................................................................................................10 Chapter 1: The CCNA Examination..............................................................................................................11 In This Chapter.....................................................................................................................................11 A Little Background about the CCNA Exam.......................................................................................11 What(cid:25)s included in CCNA certification?......................................................................................11 Who should get CCNA certification?............................................................................................12 Is CCNA related to other certifications?........................................................................................12 The Cisco Networking Academy program.....................................................................................13 Why Get CCNA Certification?.............................................................................................................13 What the CCNA Exam Covers.............................................................................................................13 OSI Reference Model.....................................................................................................................16 WAN protocols...............................................................................................................................16 Cisco IOS commands.....................................................................................................................16 Network protocols..........................................................................................................................16 Routing...........................................................................................................................................16 Network security............................................................................................................................16 LAN switching...............................................................................................................................16 Cisco career certification and survey.............................................................................................17 Taking (And Passing) the Exam...........................................................................................................17 Preparing for the Exam.........................................................................................................................17 Signing up to Take the Exam................................................................................................................18 How Much Does It Cost?......................................................................................................................18 i Table of Contents Chapter 1: The CCNA Examination World Wide Web Sites to Help You.....................................................................................................18 Where to Go from Here........................................................................................................................19 A Little Luck Never Hurts....................................................................................................................19 Chapter 2: The Language of the CCNA Exam.............................................................................................20 In This Chapter.....................................................................................................................................20 Laying Out the Network Topology.......................................................................................................20 Please accept our topologies...........................................................................................................20 Mixed topologies............................................................................................................................21 Applying LAN Technologies................................................................................................................22 Ethernet networks...........................................................................................................................22 Token Ring networks.....................................................................................................................22 FDDI: The double−ring network....................................................................................................22 Defining LANs, MANs, and WANs.....................................................................................................22 Designing Networks: An Overview......................................................................................................23 Subnet Mask Review............................................................................................................................24 Part II: The OSI Reference Model.................................................................................................................26 Chapter List............................................................................................................................................26 In this part&..........................................................................................................................................26 Chapter 3: Routing Through the OSI Model................................................................................................27 Exam Objectives...................................................................................................................................27 Quick Assessment.................................................................................................................................27 Answers.................................................................................................................................................28 The OSI: A Model of Efficiency..........................................................................................................28 Reasons why a layered−model is used...........................................................................................28 The layers of the OSI model...........................................................................................................29 Packaging the data..........................................................................................................................30 Down one side and up the other.....................................................................................................31 Getting Physical....................................................................................................................................32 Electrically speaking......................................................................................................................32 Getting to know the wire................................................................................................................32 Choosing the network cable...........................................................................................................32 Working in the Wiring Closet...............................................................................................................34 Wiring standards.............................................................................................................................34 Cross−connecting the backbone.....................................................................................................35 Physical Layer Hardware......................................................................................................................36 Could you repeat that?....................................................................................................................36 Just a hub of activity.......................................................................................................................36 Prep Test...............................................................................................................................................37 Answers.................................................................................................................................................39 Chapter 4: The Data Link Layer....................................................................................................................40 Exam Objectives...................................................................................................................................40 Quick Assessment.................................................................................................................................40 Answers.................................................................................................................................................41 Working on the Data Link Layer..........................................................................................................41 Listing the functions of Layer 2.....................................................................................................41 Stacking up the IEEE 802 standards..............................................................................................42 Ethernet and the mighty 802.3.......................................................................................................43 ii Table of Contents Chapter 4: The Data Link Layer The sublayers of the Data Link layer.............................................................................................43 Controlling access to the network..................................................................................................45 Segmenting a Network for Fun and Profit............................................................................................46 Reaping the benefits of segmentation............................................................................................47 Bridging the difference...................................................................................................................47 Encapsulating Data...............................................................................................................................49 Prep Test...............................................................................................................................................50 Answers.................................................................................................................................................52 Chapter 5: The Network Layer......................................................................................................................54 Exam Objectives...................................................................................................................................54 Quick Assessment.................................................................................................................................54 Answers.................................................................................................................................................54 Reviewing Routing Foundations..........................................................................................................55 Addressing it logically....................................................................................................................55 Moving a packet across the internetwork.......................................................................................56 Comparing routed and routing protocols........................................................................................56 Choosing static or dynamic routes.................................................................................................57 Routing, or is that rooting?.............................................................................................................57 Layer 3 devices and protocols........................................................................................................57 Routing IPX and other NetWare Stuff..................................................................................................58 Broadcasting the SAP.....................................................................................................................58 Can I get your IPX address?...........................................................................................................59 Do you have an IPX socket wrench?..............................................................................................59 Configuring the router for IPX.......................................................................................................59 Enabling IPX globally....................................................................................................................60 Interfacing locally...........................................................................................................................60 Prep Test...............................................................................................................................................61 Answers.................................................................................................................................................62 Chapter 6: The Transport Layer....................................................................................................................64 Exam Objectives...................................................................................................................................64 Quick Assessment.................................................................................................................................64 Answers.................................................................................................................................................65 Transporting Data Over the Network...................................................................................................65 Supporting the transport services...................................................................................................66 Transporting protocols...................................................................................................................66 Getting Well Connected........................................................................................................................67 The benefits of being connection−oriented....................................................................................67 Using a connectionless protocol.....................................................................................................67 Making a positively reliable delivery.............................................................................................68 Making a Fast Recovery.......................................................................................................................68 Identifying an error recovery protocol...........................................................................................68 Checking for errors.........................................................................................................................69 It(cid:25)s 100 milliseconds, do you know where your data is?..............................................................69 Going with the Flow and Staying in Control........................................................................................70 Smoothing out the bumps...............................................................................................................70 Avoiding the congestion.................................................................................................................70 Flowing through the windows........................................................................................................70 Quenching the source.....................................................................................................................71 Prep Test...............................................................................................................................................71 iii Table of Contents Chapter 6: The Transport Layer Answers.................................................................................................................................................73 Chapter 7: The Upper Layers.........................................................................................................................74 Exam Objectives...................................................................................................................................74 Quick Assessment.................................................................................................................................74 Answers.................................................................................................................................................75 Communicating on the Session Layer..................................................................................................75 Communicating a la mode..............................................................................................................75 Testing your session skills..............................................................................................................77 Presenting the Presentation Layer.........................................................................................................77 Applying the Application Layer...........................................................................................................78 A Quick Review of the OSI Model.......................................................................................................78 Prep Test...............................................................................................................................................79 Answers.................................................................................................................................................81 Part III: Routers..............................................................................................................................................83 Chapter List............................................................................................................................................83 In this part&....................................................................................................................................83 Chapter 8: Router Models...............................................................................................................................84 Exam Objectives...................................................................................................................................84 Quick Assessment.................................................................................................................................84 Answers.................................................................................................................................................85 A Layered Approach to Networks........................................................................................................85 Core layer routers...........................................................................................................................86 Distribution layer routers................................................................................................................86 Access layer routers........................................................................................................................86 Segmenting a Network with a Router...................................................................................................86 Why segment a network?...............................................................................................................87 Segmenting a LAN with a router...................................................................................................87 The specific benefits of segmenting with a router.........................................................................88 The Four Faces of Router Memory.......................................................................................................88 RAM/DRAM a ding dong..............................................................................................................89 Good old stable, non−volatile RAM..............................................................................................89 ROM is not RAM...........................................................................................................................89 Flashing the EPROM......................................................................................................................90 Discovering CDP..................................................................................................................................90 CDP protocol facts.........................................................................................................................90 How CDP works.............................................................................................................................90 Stuff to memorize about CDP........................................................................................................90 Prep Test...............................................................................................................................................91 Answers.................................................................................................................................................93 Chapter 9: Router Basics................................................................................................................................94 Exam Objectives...................................................................................................................................94 Quick Assessment.................................................................................................................................94 Answers.................................................................................................................................................95 Oh Phooey, There(cid:25)s No GUI...............................................................................................................95 Spelling and syntax: Getting it right...............................................................................................95 Accessing the router.......................................................................................................................96 Logging into the router...................................................................................................................96 iv Table of Contents Chapter 9: Router Basics Working with the Exec command interpreter................................................................................97 Other command modes you may see on the test............................................................................97 Getting By with a Little Help...............................................................................................................99 What is a four−letter word beginning with an (cid:28)h?(cid:29) ......................................................................99 Show me everything and let me pick.............................................................................................99 Help for the terminally lazy..........................................................................................................100 Okay, show me the rest................................................................................................................100 Editing History....................................................................................................................................100 Life is good with enhanced editing..............................................................................................100 Changing history..........................................................................................................................101 Your Router Needs a Name................................................................................................................101 Let(cid:25)s Play Password...........................................................................................................................102 Don(cid:25)t be so sensitive...................................................................................................................102 Getting into configuration mode..................................................................................................102 Changing the locks.......................................................................................................................102 Giving the Router an Identity.............................................................................................................104 Waving the Banner.............................................................................................................................104 Inserting descriptions where you need them................................................................................105 Prep Test.............................................................................................................................................105 Answers...............................................................................................................................................107 Chapter 10: Router Commands...................................................................................................................108 Exam Objectives.................................................................................................................................108 Quick Assessment...............................................................................................................................108 Answers...............................................................................................................................................109 Setting up and Configuring a Router..................................................................................................109 Watch out, it(cid:25)s a setup!................................................................................................................109 What(cid:25)s the password?..................................................................................................................110 Setting up the interface.................................................................................................................110 If You Start It up, It Never Stops........................................................................................................111 POST it up....................................................................................................................................111 Are you registered?......................................................................................................................111 Changing your boots....................................................................................................................112 It(cid:25)s not a trivial matter.................................................................................................................112 Backing up the flash.....................................................................................................................112 Now that it(cid:25)s started, back it up!.................................................................................................113 A command performance.............................................................................................................114 The Manual Approach to Configuration.............................................................................................115 Prep Test.............................................................................................................................................115 Answers...............................................................................................................................................117 Chapter 11: RIP, IGRP, IPX, and Convergence.........................................................................................119 Exam Objectives.................................................................................................................................119 Quick Assessment...............................................................................................................................119 Answers...............................................................................................................................................120 Routed Versus Routing Protocols.......................................................................................................120 Inside versus outside....................................................................................................................120 A routing we will go.....................................................................................................................121 Routing types you need to know for the exam.............................................................................121 Plotting the Best Course.....................................................................................................................122 Moving to the algorithm...............................................................................................................122 v Table of Contents Chapter 11: RIP, IGRP, IPX, and Convergence Routing Algorithms............................................................................................................................123 Going the distance........................................................................................................................123 The state of the network...............................................................................................................126 Classful Routing.................................................................................................................................126 Let (cid:25)er RIP...................................................................................................................................126 IGRP routing................................................................................................................................128 Routing for the Novell riche.........................................................................................................128 Prep Test.............................................................................................................................................131 Answers...............................................................................................................................................133 Part IV: Network Protocols..........................................................................................................................134 Chapter List..........................................................................................................................................134 In this part&..................................................................................................................................134 Chapter 12: Network Addressing.................................................................................................................135 Exam Objectives.................................................................................................................................135 Quick Assessment...............................................................................................................................135 Answers...............................................................................................................................................136 Getting the Address Right...................................................................................................................136 MAC addresses.............................................................................................................................136 Working with IP addresses...........................................................................................................138 IP address classes.........................................................................................................................139 The Curse of the Subnet Mask............................................................................................................141 Boolean nightmares......................................................................................................................142 Classy masks................................................................................................................................142 It(cid:25)s only a trial separation............................................................................................................143 Routing IP Addresses..........................................................................................................................143 Configuring an IP address............................................................................................................143 Verifying an IP address................................................................................................................144 Prep Test.............................................................................................................................................146 Answers...............................................................................................................................................148 Chapter 13: Subnetting.................................................................................................................................149 Exam Objectives.................................................................................................................................149 Quick Assessment...............................................................................................................................149 Answers...............................................................................................................................................150 Subnetting...........................................................................................................................................150 Subnetting networks ID................................................................................................................150 Subnetting, subnet, and subnet mask............................................................................................151 Subnetting for fun and profit........................................................................................................151 Borrowing bits to grow a subnet..................................................................................................152 Knowing how to calculate subnets...............................................................................................154 A short broadcast..........................................................................................................................157 A Little Bit of Practice........................................................................................................................157 Calculating subnets, hosts, and broadcast addresses....................................................................157 Another subnet problem, but just a little harder...........................................................................158 A Class B subnet problem............................................................................................................159 Subnet planning problem..............................................................................................................159 Prep Test.............................................................................................................................................160 Answers...............................................................................................................................................162 vi Table of Contents Chapter 14: TCP/IP.......................................................................................................................................163 Exam Objectives.................................................................................................................................163 Quick Assessment...............................................................................................................................163 Answers...............................................................................................................................................164 The TCP/IP Suite................................................................................................................................164 The TCP/IP protocols...................................................................................................................164 TCP/IP protocol stack..................................................................................................................165 Application layer protocols..........................................................................................................166 Transport Layer Protocols...................................................................................................................166 Transmission Control Protocol (TCP)..........................................................................................166 Getting to know the well−known ports........................................................................................169 Formatting the TCP segment........................................................................................................170 User Datagram Protocol (UDP)...................................................................................................171 The UDP datagram.......................................................................................................................171 Network Layer Protocols....................................................................................................................172 Internet Protocol (IP)....................................................................................................................172 Internet Control Message Protocol (ICMP).................................................................................174 Address Resolution Protocol (ARP).............................................................................................174 Reverse ARP (RARP)..................................................................................................................174 Data Encapsulation.............................................................................................................................175 Prep Test.............................................................................................................................................175 Answers...............................................................................................................................................177 Chapter 15: Security......................................................................................................................................179 Exam Objectives.................................................................................................................................179 Quick Assessment...............................................................................................................................179 Answers...............................................................................................................................................180 Configuring IP Access Lists...............................................................................................................180 IP access lists................................................................................................................................180 Filtering port traffic......................................................................................................................184 Named access lists........................................................................................................................184 Removing an access list...............................................................................................................184 Verifying the access list...............................................................................................................185 Novell IPX Access Lists.....................................................................................................................185 Standard IPX access lists..............................................................................................................186 IPX extended access lists.............................................................................................................186 SAP filters....................................................................................................................................187 Prep Test.............................................................................................................................................187 Answers...............................................................................................................................................189 Part V: LANs and WANs..............................................................................................................................191 Chapter List..........................................................................................................................................191 In this part&..................................................................................................................................191 Chapter 16: LAN Switching..........................................................................................................................192 Exam Objectives.................................................................................................................................192 Quick Assessment...............................................................................................................................192 Answers...............................................................................................................................................193 Switching Around the Network..........................................................................................................193 Talking about switches.................................................................................................................193 Switches and LANs......................................................................................................................194 Segmenting a LAN.............................................................................................................................194 vii Table of Contents Chapter 16: LAN Switching Segmentation: A quick overview.................................................................................................195 Segmenting a LAN with a bridge.................................................................................................195 Segmenting the LAN with a router..............................................................................................196 Segmenting a LAN with a switch.................................................................................................196 Applying Three Methods to Switching Success.................................................................................197 Virtually Segmenting the LAN...........................................................................................................197 Reaping the benefits of a VLAN..................................................................................................197 Configuring the VLAN one way or another.................................................................................199 Trunking together VLANs...........................................................................................................199 Prep Test.............................................................................................................................................200 Answers...............................................................................................................................................202 Chapter 17: Connecting with WAN Protocols............................................................................................203 Exam Objectives.................................................................................................................................203 Quick Assessment...............................................................................................................................203 Answers...............................................................................................................................................204 Differentiating WAN Services............................................................................................................204 Connecting with the mysterious X.25..........................................................................................204 The framer in the DLCI................................................................................................................207 ISDN and the LAPD.....................................................................................................................208 High−level communications........................................................................................................208 Getting point−to−point.................................................................................................................208 Recognizing Frame Relay...................................................................................................................209 Framing the Frame Relay frame...................................................................................................210 Flagging congestion in Frame Relay............................................................................................210 Throwing out everything over the limit.......................................................................................211 Configuring Frame Relay switching on a router..........................................................................212 So what(cid:25)s the LMI?.....................................................................................................................212 Mapping the IP to the DLCI.........................................................................................................212 Singing the subinterface homesick blues.....................................................................................213 Configuring Frame Relay.............................................................................................................213 Monitoring Frame Relay..............................................................................................................214 PPP WAN Encapsulation....................................................................................................................214 Putting ISDN to Use...........................................................................................................................215 Defining some ISDN basics.........................................................................................................215 Identifying the ISDN twins: PRI and BRI....................................................................................216 Working with ISDN BRI on a Cisco Router......................................................................................217 Prep Test.............................................................................................................................................217 Answers...............................................................................................................................................219 Part VI: The Part of Tens.............................................................................................................................221 Chapter List..........................................................................................................................................221 In this part&..................................................................................................................................221 Chapter 18: Ten Really Great Sites for Study Aids....................................................................................222 In This Chapter...................................................................................................................................222 Cisco Systems, Inc..............................................................................................................................222 BeachFront Quizzer............................................................................................................................222 Boson Software, Inc............................................................................................................................222 CramSession.com...............................................................................................................................223 MeasureUp, Inc...................................................................................................................................223 viii Table of Contents Chapter 18: Ten Really Great Sites for Study Aids MentorLabs.........................................................................................................................................223 SelfTest Software................................................................................................................................223 Welcome.to/CCNA.............................................................................................................................223 The TechWeb Encyclopedia...............................................................................................................223 Whatis.com.........................................................................................................................................223 amazon.com, barnesandnoble.com, borders.com, and fatbrain.com..................................................224 And a Few More Good Sites to Visit..................................................................................................224 Chapter 19: Ten Things to Do on Your Test Day.......................................................................................225 In This Chapter...................................................................................................................................225 Get Me to the Test on Time................................................................................................................225 Arrive Early........................................................................................................................................225 Review Your Notes One Last Time....................................................................................................226 Check In on Time................................................................................................................................226 Do a Brain Dump, But Do It on the Plastic........................................................................................226 Do the Tutorial!...................................................................................................................................226 Ready, Steady, Go...............................................................................................................................227 A New Wrinkle: There(cid:25)s No Going Back!........................................................................................227 No Hootin(cid:25) and Hollerin(cid:25) Please......................................................................................................227 Part VII: Appendixes.....................................................................................................................................228 Chapter List..........................................................................................................................................228 In this part&..................................................................................................................................228 Appendix A: Sample Test..............................................................................................................................229 Overview.............................................................................................................................................229 The OSI Reference Model............................................................................................................229 WAN Protocols............................................................................................................................232 Cisco IOS Commands..................................................................................................................235 Network Protocols........................................................................................................................237 Routing.........................................................................................................................................238 Network Security..........................................................................................................................241 LAN Switching.............................................................................................................................242 Answers...............................................................................................................................................245 Appendix B: About the CD...........................................................................................................................251 Overview.............................................................................................................................................251 System Requirements.........................................................................................................................251 Using the CD with Microsoft Windows.............................................................................................251 What You(cid:25)ll Find on the CD..............................................................................................................252 Dummies test prep tools...............................................................................................................253 Commercial demos.......................................................................................................................253 If You(cid:25)ve Got Problems (Of the CD Kind).......................................................................................254 Appendix C: Glossary....................................................................................................................................256 Overview.............................................................................................................................................256 Index...................................................................................................................................................265 A...................................................................................................................................................265 Index...................................................................................................................................................266 B...................................................................................................................................................266 Index...................................................................................................................................................266 ix