CCNA : Cisco Certified Network Associate Study Guide Sixth Edition

Transcription

1 CCNA : Cisco Certified Network Associate Study Guide Sixth Edition Todd Lammle Wiley Publishing, Inc.

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3 Advance Praise Todd s methods of discussing topics are tactfully approached so they are not confusing to the reader, and his explanations are clear and easy to understand. Amazon Reader Review I passed my CCNA on the first try after reading this book thoroughly. If you read the book and do all the review questions and written labs at the end of each chapter, you will be well prepared for the exam. Amazon Reader Review This is a great book! Todd Lammle has the ability to make complex topics simple. Cisco books are essential once you ve mastered networking basics, but there is nothing like Sybex for learning the concepts from A to Z. Amazon Reader Review Todd has been an authority in this field for as long as I can remember. His style of writing keeps the book from becoming a sleep aid and provides nuts and bolts information that is both excellent real-world reference and directly relevant to exam objectives. If you are considering taking the CCNA exam, you would be ill advised to not give this book a thorough read. Amazon Reader Review This is the first book review I have ever written on Amazon. I ve been in the computer/network support field for many years, but had almost no contact with Cisco equipment. I basically knew the enable and config Cisco commands. I had originally planned on shelling out the $3000 to take a CCNA boot camp, but decided that that was way too much money. So I bought this book instead took a week off from work (which I would have done anyway for the class), and went at it... My homegrown boot camp paid off because I passed the exam on the first try, saving almost $2900! Amazon Reader Review This is the best technical book I have ever read!! Amazon Reader Review This book is excellent resource for preparation for CCNA certification. It has needed information regarding the Cisco s objective. Sample test and Bonus Test give extra knowledge for exam s question. Users have more knowledge and practice of test exams. I will recommend this book for anyone who does not have any knowledge of CCNA material. Amazon Reader Review

4 I ve recently passed the CCNA exam with 985 out of 1000 points and Todd Lammle s book was my only study material (along with a Cisco 2500 router). It covers all relevant topics in such an easy-to-understand way and gives you a great networking/cisco knowledge to build upon. Even now, while I m pursuing other certifications, it serves as an irreplaceable reference. Every chapter concludes with review questions, hands-on exercises or labs to give you the opportunity of applying your new skills in realworld scenarios and the CD provides additional sample tests and flashcards to consolidate your knowledge. By reading the book twice and doing all the exercises you will be able to answer just about any question you may encounter on the exam. Highly recommended! Amazon Reader Review I had made three previous attempts using Cisco Press but could not get over the hump. Needless to say I was getting pretty discouraged. However, I had heard good things about the Sybex book by Todd Lammle and decided to give it a try. It was the best thing I could have done. The book read great and it explained the required concepts and topics very well. The review questions and Hand-on Labs at the end of each chapter were also very helpful. I took the test last weekend and passed!! Thank you!! Amazon Reader Review Good exam prep. I read this book and with only slight network experience was able to pass the CCNA. Amazon Reader Review There isn t much more I can say about this book than has already been said. I used Todd s guide to help me pass the CCNA in 2000 and am using him again to recertify. Just an excellent book. Period. Amazon Reader Review This book covered everything I needed to pass the exam, with hands-on experience, and the bonus material. What a great written book this is. The best I have ever read. I recommend this book highly!! Amazon Reader Review

5 CCNA : Cisco Certified Network Associate Study Guide Sixth Edition Todd Lammle Wiley Publishing, Inc.

6 Acquisitions Editor: Jeff Kellum Development Editor: Toni Zuccarini Ackley Technical Editor: Patrick J. Conlan Production Editor: Sarah Groff-Palermo Copy Editor: Judy Flynn Production Manager: Tim Tate Vice President and Executive Group Publisher: Richard Swadley Vice President and Executive Publisher: Joseph B. Wikert Vice President and Publisher: Neil Edde Media Project Supervisor: Laura Atkinson Media Development Specialist: Josh Frank Media Quality Assurance: Angie Denny Book Designers: Judy Fung and Bill Gibson Compositor: Craig Woods, Happenstance Type-O-Rama Proofreader: Nancy Riddiough Indexer: Ted Laux Anniversary Logo Design: Richard Pacifico Cover Designer: Ryan Sneed Copyright 2007 by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada ISBN: No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) , fax (978) Requests to the Publisher for permission should be addressed to the Legal Department, Wiley Publishing, Inc., Crosspoint Blvd., Indianapolis, IN 46256, (317) , fax (317) , or online at Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or Website is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Website may provide or recommendations it may make. Further, readers should be aware that Internet Websites listed in this work may have changed or disappeared between when this work was written and when it is read. For general information on our other products and services or to obtain technical support, please contact our Customer Care Department within the U.S. at (800) , outside the U.S. at (317) or fax (317) Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Library of Congress Cataloging-in-Publication Data is available from the publisher. TRADEMARKS: Wiley, the Wiley logo, and the Sybex logo are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and other countries, and may not be used without written permission. Cisco and CCNA are registered trademarks of Cisco Systems, Inc. All other trademarks are the property of their respective owners. Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book

7 To Our Valued Readers: Thank you for looking to Sybex for your CCNA exam prep needs. We at Sybex are proud of our reputation for providing certification candidates with the practical knowledge and skills needed to succeed in the highly competitive IT marketplace. This latest edition of the best-selling CCNA: Cisco Certified Network Associate Study Guide reflects our commitment to provide CCNA candidates with the most up-to-date, accurate, and accessible instructional material on the market. As with previous editions, Todd and the editors have worked hard to ensure that the study guide you hold in your hands is comprehensive, in-depth, and pedagogically sound. We re confident that this book will exceed the demanding standards of the certification marketplace and help you, the CCNA certification candidate, succeed in your endeavors. As always, your feedback is important to us. If you believe you ve identified an error in the book, please visit the Customer Support section of the Wiley website. And if you have general comments or suggestions, feel free to drop me a line directly at nedde@wiley.com. At Sybex, we re continually striving to meet the needs of individuals preparing for certification exams. Good luck in pursuit of your CCNA certification! Neil Edde Publisher Certification Sybex, an Imprint of Wiley

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9 Acknowledgments Monica Lammle s writing style and voice, editing ability, encouragement, and dedication to ensuring that my books are concise yet highly readable has been invaluable to the success of this and many other projects. She brings clarity and life to what can truly be some very arcane and difficult material! Mr. Patrick Conlan has got to be the personification of perseverance he s a rock! Patrick literally hashed and rehashed each topic in this guide with me at all hours of the day and night scrutinizing the material until we both agreed it was verifiably solid. He was so instrumental in the development of this book that I hired him at GlobalNet Training to work as a course developer and trainer! You re going to be hearing a lot more from Mr. Conlan in the technical instruction and writing arena in the future for sure. Daniel Aguilera, who has worked with me at GlobalNet Training for seven years, also worked diligently, helping me put together the bonus exams you ll find on the CD (so be sure to give him a call if you happen to find a problem <G>). Dan possesses both the intelligence and optimism required to be a great source of encouragement and a deep reservoir of problemsolving ability whenever I found myself discouraged or burned out. Toni Zuccarini Ackley was the main editor of this the newest book in the Sybex Cisco series. Thank you Toni for having the patience of Job, and for working so hard on this book with me. I m so happy (and relieved) that you took on the job and, most of all, that you didn t run screaming from the room the next day! Jeff Kellum is instrumental to my success in the Cisco world and is my acquisitions editor. Jeff, thanks for your guidance and continued patience. Although we work well together and put out fantastic material, I am sure he groans when he sees my name on caller ID! In addition, Sarah Groff-Palermo was an excellent production editor and she worked really hard to get the book done as quickly as possible, without missing the small mistakes that are so easy to over look. Judy Flynn was the copy editor and she showed me that you can actually write a book and still have patience, be helpful but yet work extremely hard to get this book out on the shelves as fast as possible, and for that I thank you tremendously. Both Sarah and Judy worked very hard editing the book for what will hopefully turn out to be a great guide to lead you on your journey toward becoming a CCNA. Finally a big thanks to Craig Woods and Happenstance-Type-O-Rama, and the CD team: Laura Atkinson, Josh Frank, and Angie Denny.

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11 Contents at a Glance Introduction Assessment Test xxiii xxxiii Chapter 1 Internetworking 1 Chapter 2 Introduction to TCP/IP 67 Chapter 3 Subnetting, Variable Length Subnet Masks (VLSMs), and Troubleshooting TCP/IP 111 Chapter 4 Cisco s Internetworking Operating System (IOS) and Security Device Manager (SDM) 171 Chapter 5 Managing a Cisco Internetwork 251 Chapter 6 IP Routing 327 Chapter 7 Enhanced IGRP (EIGRP) and Open Shortest Path First (OSPF) 417 Chapter 8 Layer 2 Switching and Spanning Tree Protocol (STP) 493 Chapter 9 Virtual LANs (VLANs) 551 Chapter 10 Security 609 Chapter 11 Network Address Translation (NAT) 669 Chapter 12 Cisco s Wireless Technologies 703 Chapter 13 Internet Protocol Version 6 (IPv6) 739 Chapter 14 Wide Area Networks 773 Glossary 851 Index 911

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13 Table of Contents Introduction Assessment Test xxiii xxxiii Chapter 1 Internetworking 1 Internetworking Basics 4 Internetworking Models 11 The Layered Approach 12 Advantages of Reference Models 12 The OSI Reference Model 13 The Application Layer 15 The Presentation Layer 16 The Session Layer 16 The Transport Layer 16 The Network Layer 22 The Data Link Layer 24 The Physical Layer 30 Ethernet Networking 31 Half- and Full-Duplex Ethernet 33 Ethernet at the Data Link Layer 34 Ethernet at the Physical Layer 37 Ethernet Cabling 39 Straight-Through Cable 39 Crossover Cable 40 Rolled Cable 40 Data Encapsulation 43 The Cisco Three-Layer Hierarchical Model 46 The Core Layer 47 The Distribution Layer 48 The Access Layer 49 Summary 49 Exam Essentials 49 Written Lab 1 50 Written Lab 1.1: OSI Questions 51 Written Lab 1.2: Defining the OSI Layers and Devices 52 Written Lab 1.3: Identifying Collision and Broadcast Domains 53 Written Lab 1.4: Binary/Decimal/Hexadecimal Conversion 53 Review Questions 56 Answers to Review Questions 60

14 xii Table of Contents Answers to Written Lab 1 62 Answer to Written Lab Answers to Written Lab Answers to Written Lab Chapter 2 Introduction to TCP/IP 67 TCP/IP and the DoD Model 68 The Process/Application Layer Protocols 70 The Host-to-Host Layer Protocols 74 The Internet Layer Protocols 83 IP Addressing 92 IP Terminology 93 The Hierarchical IP Addressing Scheme 93 Private IP Addresses 98 Broadcast Addresses 100 Summary 101 Exam Essentials 102 Written Lab Review Questions 104 Answers to Review Questions 108 Answers to Written Lab Chapter 3 Subnetting, Variable Length Subnet Masks (VLSMs), and Troubleshooting TCP/IP 111 Subnetting Basics 112 IP Subnet-Zero 113 How to Create Subnets 114 Subnet Masks 115 Classless Inter-Domain Routing (CIDR) 116 Subnetting Class C Addresses 118 Subnetting Class B Addresses 127 Subnetting Class A Addresses 134 Variable Length Subnet Masks (VLSMs) 137 VLSM Design 138 Implementing VLSM Networks 139 Summarization 147 Troubleshooting IP Addressing 150 Determining IP Address Problems 153 Summary 157 Exam Essentials 158 Written Labs Written Lab 3.1: Written Subnet Practice #1 159 Written Lab 3.2: Written Subnet Practice 159 Written Lab 3.3: Written Subnet Practice 160

15 Table of Contents xiii Review Questions 161 Answers to Review Questions 166 Answers to Written Lab Answers to Written Lab Answers to Written Lab Chapter 4 Cisco s Internetworking Operating System (IOS) and Security Device Manager (SDM) 171 The IOS User Interface 173 Cisco Router IOS 173 Connecting to a Cisco Router 173 Bringing Up a Router 175 Command-Line Interface (CLI) 179 Entering the CLI from a Non-ISR Router 180 Overview of Router Modes 181 CLI Prompts 182 Editing and Help Features 185 Gathering Basic Routing Information 189 Router and Switch Administrative Configurations 191 Hostnames 191 Banners 192 Setting Passwords 194 Encrypting Your Passwords 199 Descriptions 201 Router Interfaces 204 Bringing Up an Interface 206 Viewing, Saving, and Erasing Configurations 212 Deleting the Configuration and Reloading the Router 214 Verifying Your Configuration 214 Cisco s Security Device Manager (SDM) 223 Summary 232 Exam Essentials 233 Written Lab Hands-on Labs 235 Hands-on Lab 4.1: Logging into a Router 235 Hands-on Lab 4.2: Using the Help and Editing Features 236 Hands-on Lab 4.3: Saving a Router Configuration 237 Hands-on Lab 4.4: Setting Your Passwords 237 Hands-on Lab 4.5: Setting the Hostname, Descriptions, IP Address, and Clock Rate 239 Hands-on Lab 4.6: Installing SDM on Your Computer 241 Review Questions 242 Answers to Review Questions 247 Answers to Written Lab 4 249

16 xiv Table of Contents Chapter 5 Managing a Cisco Internetwork 251 The Internal Components of a Cisco Router 252 The Router Boot Sequence 253 Managing Configuration Register 254 Understanding the Configuration Register Bits 254 Checking the Current Configuration Register Value 256 Changing the Configuration Register 256 Recovering Passwords 258 Boot System Commands 261 Backing Up and Restoring the Cisco IOS 262 Verifying Flash Memory 263 Backing Up the Cisco IOS 264 Restoring or Upgrading the Cisco Router IOS 265 Using the Cisco IOS File System (Cisco IFS) 266 Using the SDM to Manage the Flash Memory 270 Backing Up and Restoring the Cisco Configuration 274 Backing Up the Cisco Router Configuration 275 Restoring the Cisco Router Configuration 276 Erasing the Configuration 277 Using the Cisco IOS File System to Manage Your Router s Configuration (Cisco IFS) 278 Using the SDM to Back Up/Restore and Edit the Router s Configuration 280 Using Cisco Discovery Protocol (CDP) 283 Getting CDP Timers and Holdtime Information 283 Gathering Neighbor Information 284 Gathering Interface Traffic Information 289 Gathering Port and Interface Information 290 Documenting a Network Topology Using CDP 292 Using Telnet 295 Telnetting into Multiple Devices Simultaneously 297 Checking Telnet Connections 297 Checking Telnet Users 297 Closing Telnet Sessions 298 Using SDM to Telnet into Your Router 299 Resolving Hostnames 300 Building a Host Table 300 Using DNS to Resolve Names 302 Checking Network Connectivity and Troubleshooting 305 Using the ping Command 305 Using the traceroute Command 307 Debugging 308 Using the show processes Command 310 Summary 311

17 Table of Contents xv Exam Essentials 311 Written Lab Hands-on Labs 313 Hands-on Lab 5.1: Backing Up Your Router IOS 314 Hands-on Lab 5.2: Upgrading or Restoring Your Router IOS 314 Hands-on Lab 5.3: Backing Up the Router Configuration 314 Hands-on Lab 5.4: Using the Cisco Discovery Protocol (CDP) 315 Hands-on Lab 5.5: Using Telnet 316 Hands-on Lab 5.6: Resolving Hostnames 316 Review Questions 318 Answers to Review Questions 323 Answers to Written Lab Chapter 6 IP Routing 327 Routing Basics 329 The IP Routing Process 331 Testing Your IP Routing Understanding 336 Configuring IP Routing 341 Configuring IP Routing in Our Network 362 Static Routing 363 Default Routing 374 Dynamic Routing 377 Routing Protocol Basics 377 Distance-Vector Routing Protocols 379 Routing Loops 380 Routing Information Protocol (RIP) 383 RIP Timers 383 Configuring RIP Routing 383 Verifying the RIP Routing Tables 387 Configuring RIP Routing Example Holding Down RIP Propagations 390 RIP Version 2 (RIPv2) 390 Interior Gateway Routing Protocol (IGRP) 392 Verifying Your Configurations 393 The show ip protocols Command 394 The debug ip rip Command 395 Enabling RIPv2 on Our Internetwork 398 Summary 401 Exam Essentials 401 Written Lab Hands-on Labs 403 Hands-on Lab 6.1: Creating Static Routes 404 Hands-on Lab 6.2: Configuring RIP Routing 405

18 xvi Table of Contents Review Questions 407 Answers to Review Questions 413 Answers to Written Lab Chapter 7 Enhanced IGRP (EIGRP) and Open Shortest Path First (OSPF) 417 EIGRP Features and Operation 418 Protocol-Dependent Modules 419 Neighbor Discovery 419 Reliable Transport Protocol (RTP) 421 Diffusing Update Algorithm (DUAL) 421 Using EIGRP to Support Large Networks 422 Multiple ASes 422 VLSM Support and Summarization 423 Route Discovery and Maintenance 424 Configuring EIGRP 426 Corp 429 R1 429 R2 430 R3 430 Redistributing to the 871W Router from R3 432 Configuring Discontiguous Networks 434 Load Balancing with EIGRP 435 Verifying EIGRP 438 Open Shortest Path First (OSPF) Basics 444 OSPF Terminology 446 SPF Tree Calculation 448 Configuring OSPF 449 Enabling OSPF 449 Configuring OSPF Areas 450 Configuring Our Network with OSPF 453 Verifying OSPF Configuration 457 The show ip ospf Command 458 The show ip ospf database Command 459 The show ip ospf interface Command 460 The show ip ospf neighbor Command 461 The show ip protocols Command 461 Debugging OSPF 462 OSPF DR and BDR Elections 465 Neighbors 465 Adjacencies 465 DR and BDR Elections 466 OSPF and Loopback Interfaces 466 Configuring Loopback Interfaces 467 OSPF Interface Priorities 469

19 Table of Contents xvii Troubleshooting OSPF 471 Configuring EIGRP and OSPF Summary Routes 474 Summary 476 Exam Essentials 477 Written Lab Hands-on Labs 478 Hands-on Lab 7.1: Configuring and Verifying EIGRP 479 Hands-on Lab 7.2: Enabling the OSPF Process 480 Hands-on Lab 7.3: Configuring OSPF Neighbors 481 Hands-on Lab 7.4: Verifying OSPF Operation 482 Hands-on Lab 7.5: OSPF DR and BDR Elections 482 Review Questions 484 Answers to Review Questions 489 Answers to Written Lab Chapter 8 Layer 2 Switching and Spanning Tree Protocol (STP) 493 Before Layer 2 Switching 494 Switching Services 497 Limitations of Layer 2 Switching 498 Bridging vs. LAN Switching 499 Three Switch Functions at Layer Spanning Tree Protocol (STP) 505 Spanning Tree Terms 506 Spanning Tree Operations 507 Configuring Catalyst Switches 514 Catalyst Switch Configuration 515 Verifying Cisco Catalyst Switches 528 Cisco Network Assistant 534 Summary 541 Exam Essentials 542 Written Lab Review Questions 543 Answers to Review Questions 548 Answers to Written Lab Chapter 9 Virtual LANs (VLANs) 551 VLAN Basics 552 Broadcast Control 554 Security 555 Flexibility and Scalability 555 VLAN Memberships 558 Static VLANs 558 Dynamic VLANs 559

20 xviii Table of Contents Identifying VLANs 559 Frame Tagging 561 VLAN Identification Methods 562 VLAN Trunking Protocol (VTP) 563 VTP Modes of Operation 564 VTP Pruning 565 Routing between VLANs 567 Configuring VLANs 568 Assigning Switch Ports to VLANs 570 Configuring Trunk Ports 571 Configuring Inter-VLAN Routing 575 Configuring VTP 580 Troubleshooting VTP 583 Telephony: Configuring Voice VLANs 586 Configuring the Voice VLAN 587 Configuring IP Phone Voice Traffic 587 Using the CNA to Configure VLANs and Inter-VLAN Routing 588 Summary 597 Exam Essentials 598 Written Lab Review Questions 600 Answers to Review Questions 605 Answers to Written Lab Chapter 10 Security 609 Perimeter, Firewall, and Internal Routers 610 Recognizing Security Threats 611 Mitigating Security Threats 614 Cisco s IOS Firewall 614 Introduction to Access Lists 615 Mitigating Security Issues with ACLs 618 Standard Access Lists 619 Wildcard Masking 620 Standard Access List Example 622 Controlling VTY (Telnet) Access 625 Extended Access Lists 626 Extended Access List Example Extended Access List Example Advanced Access Lists 632 Named ACLs 632 Switch Port ACLs 634 Lock and Key (Dynamic ACLs) 636 Reflexive ACLs 637 Time-Based ACLs 637

21 Table of Contents xix Remarks 638 Context-Based Access Control (Cisco IOS Firewall) 639 Authentication Proxy 640 Monitoring Access Lists 640 Configuring Access Lists Using SDM 643 Creating ACLs with SDM 643 Creating Firewalls with SDM 647 Summary 654 Exam Essentials 655 Written Lab Hands-on Labs 656 Hands-on Lab 10.1: Standard IP Access Lists 657 Hands-on Lab 10.2: Extended IP Access Lists 657 Review Questions 661 Answers to Review Questions 666 Answers to Written Lab Chapter 11 Network Address Translation (NAT) 669 When Do We Use NAT? 670 Types of Network Address Translation 671 NAT Names 672 How NAT Works 673 Static NAT Configuration 674 Dynamic NAT Configuration 675 PAT (Overloading) Configuration 675 Simple Verification of NAT 676 Testing and Troubleshooting NAT 677 Configuring NAT on Our Internetwork 679 Configuring NAT Using SDM 684 Summary 688 Exam Essentials 688 Written Lab Hands-on Labs 689 Lab 11.1: Preparing for NAT 691 Lab 11.2: Configuring Dynamic NAT 692 Lab 11.3: Configuring PAT 694 Review Questions 696 Answers to Review Questions 699 Answers to Written Lab Chapter 12 Cisco s Wireless Technologies 703 Introduction to Wireless Technology 704 The Standards 706 Comparing

22 xx Table of Contents Cisco s Unified Wireless Solution 712 Split-MAC Architecture 715 MESH and LWAPP 716 AWPP 718 Wireless Security 718 Configuring Our Wireless Internetwork 721 Summary 729 Exam Essentials 729 Written Lab Review Questions 731 Answers to Review Questions 735 Answers to Written Lab Chapter 13 Internet Protocol Version 6 (IPv6) 739 Why Do We Need IPv6? 740 The Benefits and Uses of IPv6 741 IPv6 Addressing and Expressions 742 Shortened Expression 743 Address Types 744 Special Addresses 745 How IPv6 Works in an Internetwork 746 Autoconfiguration 746 Configuring Cisco Routers with IPv6 747 DHCPv6 748 ICMPv6 749 IPv6 Routing Protocols 750 RIPng 751 EIGRPv6 751 OSPFv3 752 Migrating to IPv6 753 Dual Stacking 754 6to4 Tunneling 754 NAT-PT 755 Configuring IPv6 on Our Internetwork 756 Configuring RIPng 759 Configuring OSPFv3 763 Summary 766 Exam Essentials 767 Written Lab Review Questions 768 Answers to Review Questions 771 Answers to Written Lab

23 Table of Contents xxi Chapter 14 Wide Area Networks 773 Introduction to Wide Area Networks 774 Defining WAN Terms 775 WAN Connection Types 775 WAN Support 777 Cable and DSL 779 Cable 780 Digital Subscriber Line (DSL) 782 Cabling the Serial Wide Area Network 785 Serial Transmission 785 Data Terminal Equipment and Data Communication Equipment 786 High-Level Data-Link Control (HDLC) Protocol 787 Point-to-Point Protocol (PPP) 788 Link Control Protocol (LCP) Configuration Options 789 PPP Session Establishment 790 PPP Authentication Methods 790 Configuring PPP on Cisco Routers 791 Configuring PPP Authentication 791 Verifying PPP Encapsulation 792 PPPoE Configuration 796 Frame Relay 798 Introduction to Frame Relay Technology 798 Frame Relay Implementation and Monitoring 805 Using SDM for WAN Connections 813 Configuring PPP with Authentication Using SDM 813 Configuring PPPoE with SDM 818 Configuring Frame Relay with SDM 822 Virtual Private Networks 825 Introduction to Cisco IOS IPSec 826 IPSec Transforms 826 Configuring VPNs/IPSec Using the SDM 828 Summary 836 Exam Essentials 836 Written Lab Hands-on Labs 837 Hands-on Lab 14.1: Configuring PPP Encapsulation and Authentication 838 Hands-on Lab 14.2: Configuring and Monitoring HDLC 839 Hands-on Lab 14.3: Configuring Frame Relay and Subinterfaces 840

24 xxii Table of Contents Review Questions 842 Answers to Review Questions 847 Answers to Written Lab Glossary 851 Index 911

25 Introduction Welcome to the exciting world of Cisco certification! You have picked up this book because you want something better namely, a better job with more satisfaction. Rest assured that you have made a good decision. Cisco certification can help you get your first networking job or more money and a promotion if you are already in the field. Cisco certification can also improve your understanding of the internetworking of more than just Cisco products: You will develop a complete understanding of networking and how different network topologies work together to form a network. This is beneficial to every networking job and is the reason Cisco certification is in such high demand, even at companies with few Cisco devices. Cisco is the king of routing, switching, and security, the Microsoft of the internetworking world. The Cisco certifications reach beyond the popular certifications, such as the MCSE, to provide you with an indispensable factor in understanding today s network insight into the Cisco world of internetworking. By deciding that you want to become Cisco certified, you are saying that you want to be the best the best at routing and the best at switching. This book will lead you in that direction. For up-to-the minute updates covering additions or modifications to the CCNA certification exams, as well as additional study tools and review questions, be sure to visit the Todd Lammle forum and website at and/or Cisco s Network Support Certifications Initially, to secure the coveted Cisco CCIE certification, you took only one test and then you were faced with the (extremely difficult) hands-on lab, an all-or-nothing approach that made it tough to succeed. In response, Cisco created a series of new certifications to help you get the coveted CCIE as well as aid prospective employers in measuring skill levels. With these new certifications, which make for a better approach to preparing for that almighty lab, Cisco opened doors that few were allowed through before. This book covers everything CCNA related. For up-to-date information on Todd Lammle Cisco Authorized CCNA CCNP, CCSP, CCVP, and CCIE bootcamps, please see and/or

26 xxiv Introduction Cisco Certified Network Associate (CCNA) The CCNA certification was the first in the new line of Cisco certifications and was the precursor to all current Cisco certifications. Now you can become a Cisco Certified Network Associate for the meager cost of this book and either one test at $150 or two tests at $125 each although the CCNA exams are extremely hard and cover a lot of material, so you have to really know your stuff! Taking a Cisco class or spending months with hands-on experience is not out of the norm. And once you have your CCNA, you don t have to stop there you can choose to continue with your studies and achieve a higher certification, called the Cisco Certified Network Professional (CCNP). Someone with a CCNP has all the skills and knowledge he or she needs to attempt the Routing and Switching CCIE lab. But just becoming a CCNA can land you that job you ve dreamed about. Why Become a CCNA? Cisco, not unlike Microsoft and Novell (Linux), has created the certification process to give administrators a set of skills and to equip prospective employers with a way to measure skills or match certain criteria. Becoming a CCNA can be the initial step of a successful journey toward a new, highly rewarding, and sustainable career. The CCNA program was created to provide a solid introduction not only to the Cisco Internetwork Operating System (IOS) and Cisco hardware, but also to internetworking in general, making it helpful to you in areas that are not exclusively Cisco s. At this point in the certification process, it s not unrealistic that network managers even those without Cisco equipment require Cisco certifications for their job applicants. If you make it through the CCNA and are still interested in Cisco and internetworking, you re headed down a path to certain success. What Skills Do You Need to Become a CCNA? To meet the CCNA certification skill level, you must be able to understand or do the following: A CCNA certified professional can install, configure, and operate LAN, WAN, and wireless access services securely, as well as troubleshoot and configure small to medium networks (500 nodes or fewer) for performance. This knowledge includes, but is not limited to, use of these protocols: IP, IPv6, EIGRP, RIP, RIPv2, OSPF, serial connections, Frame Relay, cable, DSL, PPPoE, LAN switching, VLANs, Ethernet, security, and access lists. Be sure and check my web site and/or Cisco s web site for the latest Cisco CCNA objectives and other Cisco exams, objectives, and certifications that can change on a moment s notice

27 Introduction xxv How Do You Become a CCNA? The way to become a CCNA is to pass one little test (CCNA Composite exam ). Then poof! you re a CCNA. (Don t you wish it were that easy?) True, it can be just one test, but you still have to possess enough knowledge to understand what the test writers are saying. However, Cisco has a two-step process that you can take in order to become a CCNA that may or may not be easier than taking one longer exam (this book is based on the one-step method ); however, this book has all the information you need to pass all three exams. The two-step method involves passing the following: Exam : Interconnecting Cisco Networking Devices 1(ICND1) Exam : Introduction to Cisco Networking Devices 2 (ICND2) I can t stress this enough: It s critical that you have some hands-on experience with Cisco routers. If you can get ahold of some 1841 or 2800 series routers, you re set. But if you can t, I ve worked hard to provide hundreds of configuration examples throughout this book to help network administrators (or people who want to become network administrators) learn what they need to know to pass the CCNA exam. Since the new exam is so hard, Cisco wants to reward you for taking the two-test approach. Or so it seems. If you take the ICND1 exam, you actually receive a certification called the CCENT (Cisco Certified Entry Networking Technician). This is one step toward your CCNA. To achieve your CCNA, you must still pass your ICND2 exam. Again, this book was written for the CCNA Composite exam one exam and you get your certification. For Cisco Authorized hands-on training with CCSI Todd Lammle, please see Each student will get hands-on experience by configuring at least three routers and two switches no sharing of equipment! What Does This Book Cover? This book covers everything you need to know in order to pass the CCNA exam. However, taking the time to study and practice with routers or a router simulator is the real key to success. You will learn the following information in this book: Chapter 1 introduces you to internetworking. You will learn the basics of the Open Systems Interconnection (OSI) model the way Cisco wants you to learn it. Ethernet networking and standards are discussed in detail in this chapter as well. There are written labs and plenty of review questions to help you. Do not skip the written labs in this chapter! Chapter 2 provides you with the background necessary for success on the exam as well as in the real world by discussing TCP/IP. This in-depth chapter covers the very beginnings of the Internet Protocol stack and then goes all the way to IP addressing and understanding the difference between a network address and a broadcast address before finally ending with network troubleshooting.

28 xxvi Introduction Chapter 3 introduces you to subnetting. You will be able to subnet a network in your head after reading this chapter. In addition, you ll learn about Variable Length Subnet Masks (VLSMs) and how to design a network using VLSMs. This chapter will finish with summarization techniques and configurations. Plenty of help is found in this chapter if you do not skip the Written Lab and Review Questions. Chapter 4 introduces you to the Cisco Internetwork Operating System (IOS) and commandline interface (CLI). In this chapter you will learn how to turn on a router and configure the basics of the IOS, including setting passwords, banners, and more. IP configuration using the Secure Device Manager (SDM) will be discussed and Hands-on Labs will help you gain a firm grasp of the concepts taught in the chapter. Before you go through the Hands-on Labs, be sure to complete the Written Lab and Review Questions. Chapter 5 provides you with the management skills needed to run a Cisco IOS network. Backing up and restoring the IOS, as well as router configuration, is covered, as are the troubleshooting tools necessary to keep a network up and running. Before performing the Hands-on Labs in this chapter, complete the Written Lab and Review Questions. Chapter 6 teaches you about IP routing. This is a fun chapter, because you will begin to build your network, add IP addresses, and route data between routers. You will also learn about static, default, and dynamic routing using RIP and RIPv2 (with a small touch of IGRP). Written and Hands-on Labs will help you understand IP routing to the fullest. Chapter 7 dives into more complex dynamic routing with Enhanced IGRP and OSPF routing. The Written Lab, Hands-on Labs, and Review Questions will help you master these routing protocols. Chapter 8 gives you a background on layer 2 switching and how switches perform address learning and make forwarding and filtering decisions. Network loops and how to avoid them with the Spanning Tree Protocol (STP) will be discussed, as well as the 802.1w STP version. Go through the Written Lab and Review Questions to help you really understand the basic layer 2 switching on an internetwork. Chapter 9 covers virtual LANs and how you can use them in your internetwork. This chapter also covers the nitty-gritty of VLANs and the different concepts and protocols used with VLANs, as well as troubleshooting. The Written Lab and Review Questions will reinforce the VLAN material. Chapter 10 covers security and access lists, which are created on routers to filter the network. IP standard, extended, and named access lists are covered in detail. Written and Hands-on Labs, along with Review Questions, will help you study for the security and access-list portion of the CCNA Composite exam. Chapter 11 covers Network Address Translation (NAT). This chapter has been on the Sybex website for a few years as an update to my last CCNA book, but I updated it and added it to this edition. New information, commands, troubleshooting, and labs will help you nail the NAT CCNA objectives. Chapter 12 covers wireless technologies. This is an introductory chapter regarding wireless technologies as Cisco sees them. However, I also added some advanced wireless topics that cover Cisco s newest gear. At this time, advanced wireless is not covered within the Cisco CCNA objectives, but that can change on any given day. Make sure you understand

29 Introduction xxvii your basic wireless technologies like access points and clients, as well as the difference between a, b, and g. Chapter 13 covers IPv6. This is a fun chapter and has some great information. IPv6 is not the big, bad scary monster that most people think it is. IPv6 is an objective on this new exam, so study this chapter carefully. Keep an eye out at for late-breaking updates. Chapter 14 concentrates on Cisco wide area network (WAN) protocols. This chapter covers HDLC, PPP, and Frame Relay in depth, as well as other protocols we use on a daily basis like Cable, DSL and PPPoE. You must be proficient in all these protocols to be successful on the CCNA exam. Do not skip the Written Lab, Review Questions, or Hands-on Labs found in this chapter. How to Use This Book If you want a solid foundation for the serious effort of preparing for the Cisco Certified Network Associate (CCNA Composite) exam, then look no further. I have spent hundreds of hours putting together this book with the sole intention of helping you to pass the CCNA exam and learn how to configure Cisco routers and switches (among hundreds of other things!). This book is loaded with valuable information, and you will get the most out of your studying time if you understand how I put the book together. To best benefit from this book, I recommend the following study method: 1. Take the assessment test immediately following this introduction. (The answers are at the end of the test.) It s okay if you don t know any of the answers; that is why you bought this book! Carefully read over the explanations for any question you get wrong and note the chapters in which the material is covered. This information should help you plan your study strategy. Honestly, my recommendation is to just start reading from Chapter 1 and don t stop until you re all the way through Chapter Study each chapter carefully, making sure that you fully understand the information and the test objectives listed at the beginning of each one. Pay extra-close attention to any chapter that includes material covered in questions you missed in the assessment test. 3. Complete each Written Lab at the end of each chapter. Do not skip these written exercises because they directly relate to the CCNA Composite objectives and what you must glean from the chapters in which they appear. Do not just skim these labs! Make sure you understand completely the reason for each answer. 4. Complete all Hands-on Labs in the chapter (not all chapters have hands-on labs, referring to the text of the chapter so that you understand the reason for each step you take. If you do not have Cisco equipment available, go to for a router simulator that will cover all the hands-on labs needed for all your Cisco certification needs. 5. Answer all of the Review Questions related to each chapter. (The answers appear at the end of the chapters.) Note the questions that confuse you and study those sections of the book again. Do not just skim these questions! Make sure you understand completely the reason for each answer. Remember that these will not be the exact questions you find on the exam; they are written to help you understand the chapter material.

30 xxviii Introduction 6. Try your hand at the bonus exams that are included on the companion CD. The questions in these exams appear only on the CD. Check out for more Cisco exam prep questions. The questions found at will be updated at least monthly, if not weekly or even daily! Before you take your test, be sure and visit my web site for questions, videos, audios and other useful information. 7. Also on the companion CD is the first module from my complete CCNA video series, which covers internetworking and basic networking. This is critical for the CCNA exam. In addition, as an added bonus, I have included an audio section from my CCNA audio program. Do not skip the video and audio section! Just a note to let you know that I mention the test number in the video and audio sections. This is nothing to be concerned about as the information presented is valid for both the and exam. 8. Test yourself using all the flashcards on the CD. These are brand new and updated flashcard programs to help you prepare for the CCNA exam. These are a great study tool! To learn every bit of the material covered in this book, you ll have to apply yourself regularly, and with discipline. Try to set aside the same time period every day to study, and select a comfortable and quiet place to do so. If you work hard, you will be surprised at how quickly you learn this material. If you follow the steps listed above and really study and practice the Review Questions, bonus exams, the Todd Lammle video/audio sections, and the electronic flashcards, as well as all the Written and Hands-on Labs, it would be hard to fail the CCNA Composite exam. However, studying for the CCNA exam is like trying to get in shape if you do not go to the gym every day, you won t get in shape. What s on the CD? We worked hard to provide some really great tools to help you with your certification process. All of the following tools should be loaded on your workstation when you re studying for the test. As a fantastic bonus, I was able to add a section from both my CCNA video and audio series to the CD included with this book! The Sybex Test Preparation Software The test preparation software prepares you to pass the CCNA exam. In this test engine, you will find all the review and assessment questions from the book, plus two additional bonus exams that appear exclusively on the CD. Electronic Flashcards for PC, Pocket PC, and Palm Devices To prepare for the exam, you can read this book, study the Review Questions at the end of each chapter, and work through the practice exams included in the book and on the companion CD. But wait, there s more! You can also test yourself with the flashcards included on the