- •Warning and Disclaimer
- •Feedback Information
- •Trademark Acknowledgments
- •About the Author
- •About the Technical Reviewers
- •Dedication
- •Acknowledgments
- •Contents at a Glance
- •Contents
- •Icons Used in This Book
- •Command Syntax Conventions
- •Cisco’s Motivation: Certifying Partners
- •Format of the CCNA Exams
- •What’s on the CCNA Exams
- •ICND Exam Topics
- •Cross-Reference Between Exam Topics and Book Parts
- •CCNA Exam Topics
- •INTRO and ICND Course Outlines
- •Objectives and Methods
- •Book Features
- •How This Book Is Organized
- •Part I: LAN Switching
- •Part II: TCP/IP
- •Part III: Wide-Area Networks
- •Part IV: Network Security
- •Part V: Final Preparation
- •Part VI: Appendixes
- •How to Use These Books to Prepare for the CCNA Exam
- •For More Information
- •Part I: LAN Switching
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Brief Review of LAN Switching
- •The Forward-Versus-Filter Decision
- •How Switches Learn MAC Addresses
- •Forwarding Unknown Unicasts and Broadcasts
- •LAN Switch Logic Summary
- •Basic Switch Operation
- •Foundation Summary
- •Spanning Tree Protocol
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Spanning Tree Protocol
- •What IEEE 802.1d Spanning Tree Does
- •How Spanning Tree Works
- •Electing the Root and Discovering Root Ports and Designated Ports
- •Reacting to Changes in the Network
- •Spanning Tree Protocol Summary
- •Optional STP Features
- •EtherChannel
- •PortFast
- •Rapid Spanning Tree (IEEE 802.1w)
- •RSTP Link and Edge Types
- •RSTP Port States
- •RSTP Port Roles
- •RSTP Convergence
- •Edge-Type Behavior and PortFast
- •Link-Type Shared
- •Link-Type Point-to-Point
- •An Example of Speedy RSTP Convergence
- •Basic STP show Commands
- •Changing STP Port Costs and Bridge Priority
- •Foundation Summary
- •Foundation Summary
- •Virtual LANs and Trunking
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Review of Virtual LAN Concepts
- •Trunking with ISL and 802.1Q
- •ISL and 802.1Q Compared
- •VLAN Trunking Protocol (VTP)
- •How VTP Works
- •VTP Pruning
- •Foundation Summary
- •Part II: TCP/IP
- •IP Addressing and Subnetting
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •IP Addressing Review
- •IP Subnetting
- •Analyzing and Interpreting IP Addresses and Subnets
- •Math Operations Used to Answer Subnetting Questions
- •Converting IP Addresses from Decimal to Binary and Back Again
- •The Boolean AND Operation
- •How Many Hosts and How Many Subnets?
- •What Is the Subnet Number, and What Are the IP Addresses in the Subnet?
- •Finding the Subnet Number
- •Finding the Subnet Broadcast Address
- •Finding the Range of Valid IP Addresses in a Subnet
- •Finding the Answers Without Using Binary
- •Easier Math with Easy Masks
- •Which Subnet Masks Meet the Stated Design Requirements?
- •What Are the Other Subnet Numbers?
- •Foundation Summary
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Extended ping Command
- •Distance Vector Concepts
- •Distance Vector Loop-Avoidance Features
- •Route Poisoning
- •Split Horizon
- •Split Horizon with Poison Reverse
- •Hold-Down Timer
- •Triggered (Flash) Updates
- •RIP and IGRP
- •IGRP Metrics
- •Examination of RIP and IGRP debug and show Commands
- •Issues When Multiple Routes to the Same Subnet Exist
- •Administrative Distance
- •Foundation Summary
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Link-State Routing Protocol and OSPF Concepts
- •Steady-State Operation
- •Loop Avoidance
- •Scaling OSPF Through Hierarchical Design
- •OSPF Areas
- •Stub Areas
- •Summary: Comparing Link-State and OSPF to Distance Vector Protocols
- •Balanced Hybrid Routing Protocol and EIGRP Concepts
- •EIGRP Loop Avoidance
- •EIGRP Summary
- •Foundation Summary
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Route Summarization and Variable-Length Subnet Masks
- •Route Summarization Concepts
- •VLSM
- •Route Summarization Strategies
- •Sample “Best” Summary on Seville
- •Sample “Best” Summary on Yosemite
- •Classless Routing Protocols and Classless Routing
- •Classless and Classful Routing Protocols
- •Autosummarization
- •Classful and Classless Routing
- •Default Routes
- •Classless Routing
- •Foundation Summary
- •Advanced TCP/IP Topics
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Scaling the IP Address Space for the Internet
- •CIDR
- •Private Addressing
- •Network Address Translation
- •Static NAT
- •Dynamic NAT
- •Overloading NAT with Port Address Translation (PAT)
- •Translating Overlapping Addresses
- •Miscellaneous TCP/IP Topics
- •Internet Control Message Protocol (ICMP)
- •ICMP Echo Request and Echo Reply
- •Destination Unreachable ICMP Message
- •Time Exceeded ICMP Message
- •Redirect ICMP Message
- •Secondary IP Addressing
- •FTP and TFTP
- •TFTP
- •MTU and Fragmentation
- •Foundation Summary
- •Part III: Wide-Area Networks
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Review of WAN Basics
- •Physical Components of Point-to-Point Leased Lines
- •Data-Link Protocols for Point-to-Point Leased Lines
- •HDLC and PPP Compared
- •Looped Link Detection
- •Enhanced Error Detection
- •Authentication Over WAN Links
- •PAP and CHAP Authentication
- •Foundation Summary
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •ISDN Protocols and Design
- •Typical Uses of ISDN
- •ISDN Channels
- •ISDN Protocols
- •ISDN BRI Function Groups and Reference Points
- •ISDN PRI Function Groups and Reference Points
- •BRI and PRI Encoding and Framing
- •PRI Encoding
- •PRI Framing
- •BRI Framing and Encoding
- •DDR Step 1: Routing Packets Out the Interface to Be Dialed
- •DDR Step 2: Determining the Subset of the Packets That Trigger the Dialing Process
- •DDR Step 3: Dialing (Signaling)
- •DDR Step 4: Determining When the Connection Is Terminated
- •ISDN and DDR show and debug Commands
- •Multilink PPP
- •Foundation Summary
- •Frame Relay
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Frame Relay Protocols
- •Frame Relay Standards
- •Virtual Circuits
- •LMI and Encapsulation Types
- •DLCI Addressing Details
- •Network Layer Concerns with Frame Relay
- •Layer 3 Addressing with Frame Relay
- •Frame Relay Layer 3 Addressing: One Subnet Containing All Frame Relay DTEs
- •Frame Relay Layer 3 Addressing: One Subnet Per VC
- •Frame Relay Layer 3 Addressing: Hybrid Approach
- •Broadcast Handling
- •Frame Relay Service Interworking
- •A Fully-Meshed Network with One IP Subnet
- •Frame Relay Address Mapping
- •A Partially-Meshed Network with One IP Subnet Per VC
- •A Partially-Meshed Network with Some Fully-Meshed Parts
- •Foundation Summary
- •Part IV: Network Security
- •IP Access Control List Security
- •“Do I Know This Already?” Quiz
- •Foundation Topics
- •Standard IP Access Control Lists
- •IP Standard ACL Concepts
- •Wildcard Masks
- •Standard IP ACL: Example 2
- •Extended IP Access Control Lists
- •Extended IP ACL Concepts
- •Extended IP Access Lists: Example 1
- •Extended IP Access Lists: Example 2
- •Miscellaneous ACL Topics
- •Named IP Access Lists
- •Controlling Telnet Access with ACLs
- •ACL Implementation Considerations
- •Foundation Summary
- •Part V: Final Preparation
- •Final Preparation
- •Suggestions for Final Preparation
- •Preparing for the Exam Experience
- •Final Lab Scenarios
- •Scenario 1
- •Scenario 1, Part A: Planning
- •Solutions to Scenario 1, Part A: Planning
- •Scenario 2
- •Scenario 2, Part A: Planning
- •Solutions to Scenario 2, Part A: Planning
- •Part VI: Appendixes
- •Glossary
- •Answers to the “Do I Know This Already?” Quizzes and Q&A Questions
- •Chapter 1
- •“Do I Know This Already?” Quiz
- •Chapter 2
- •“Do I Know This Already?” Quiz
- •Chapter 3
- •“Do I Know This Already?” Quiz
- •Chapter 4
- •“Do I Know This Already?” Quiz
- •Chapter 5
- •“Do I Know This Already?” Quiz
- •Chapter 6
- •“Do I Know This Already?” Quiz
- •Chapter 7
- •“Do I Know This Already?” Quiz
- •Chapter 8
- •“Do I Know This Already?” Quiz
- •Chapter 9
- •“Do I Know This Already?” Quiz
- •Chapter 10
- •“Do I Know This Already?” Quiz
- •Chapter 11
- •“Do I Know This Already?” Quiz
- •Chapter 12
- •“Do I Know This Already?” Quiz
- •Using the Simulation Software for the Hands-on Exercises
- •Accessing NetSim from the CD
- •Hands-on Exercises Available with NetSim
- •Scenarios
- •Labs
- •Listing of the Hands-on Exercises
- •How You Should Proceed with NetSim
- •Considerations When Using NetSim
- •Routing Protocol Overview
- •Comparing and Contrasting IP Routing Protocols
- •Routing Through the Internet with the Border Gateway Protocol
- •RIP Version 2
- •The Integrated IS-IS Link State Routing Protocol
- •Summary of Interior Routing Protocols
- •Numbering Ports (Interfaces)
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Table I-4 CCNA Exam Topics (Continued)
Exam Topic |
|
Reference Number |
Exam Topic |
|
|
23 |
Troubleshoot an access list |
|
|
24 |
Perform simple WAN troubleshooting |
|
|
|
Technology |
|
|
25 |
Describe network communications using layered models |
|
|
26 |
Describe the Spanning Tree process |
|
|
27 |
Compare and contrast key characteristics of LAN environments |
|
|
28 |
Evaluate the characteristics of routing protocols |
|
|
29 |
Evaluate TCP/IP communication process and its associated protocols |
|
|
30 |
Describe the components of network devices |
|
|
31 |
Evaluate rules for packet control |
|
|
32 |
Evaluate key characteristics of WANs |
|
|
INTRO and ICND Course Outlines
Another way to get some direction for the topics on the exams is to look at the course outlines for the related courses. Cisco offers the Introduction to Cisco Networking (INTRO) and Interconnecting Cisco Network Devices (ICND) courses through its Certified Learning Solutions Providers (CLSPs). CLSPs in turn work with other learning partners as well.
The INTRO course covers a much broader set of topics than ICND, but for the topics it covers, ICND covers the topics in much greater detail. In particular, ICND includes a lot more information about commands used on routers and switches to configure and troubleshoot the various features.
These outlines can be found at www.cisco.com.
About the CCNA INTRO Exam Certification Guide and CCNA ICND Exam Certification Guide
As mentioned earlier in this Introduction, you can take both the INTRO and ICND exams to pass CCNA, or you can take a single CCNA exam. Because of the significantly expanded topics as compared with the previous CCNA exam, there was simply too much material for a single book. So we created two books—one for the INTRO exam and one for the ICND exam.
xxv
The contents of the two books were designed for both the single-exam and dual-exam audience. If you’re preparing for just the ICND exam, you can read just this book. Because the ICND exam covers topics more deeply than the INTRO exam, you should probably pass the INTRO exam first. Use the CCNA INTRO Exam Certification Guide to help with that task.
If you are studying for the CCNA exam, you can use both books and alternate reading each book to optimize your efforts in preparing for the exam. This Introduction includes a reading plan for anyone taking the CCNA exam, telling you in what order to read the chapters in the two books. Essentially, you read the first three parts of this book and then read part of the other book, come back here for a part, go back to the other book, and so on, for most of the parts of both books. The parts are named so that it is obvious which sections to read as you move between the books. By doing so, you complete all the coverage in a particular technical area before moving on to another.
Objectives and Methods
The most important and somewhat obvious objective of this book is to help you pass the ICND exam or the CCNA exam. In fact, if the primary objective of this book were different, the book’s title would be misleading! However, the methods used in this book to help you pass the exams are also designed to make you much more knowledgeable about how to do your job.
This book uses several key methodologies to help you discover the exam topics on which you need more review, to help you fully understand and remember those details, and to help you prove to yourself that you have retained your knowledge of those topics. This book does not try to help you pass the exams only by memorization, but by truly learning and understanding the topics. The CCNA certification is the foundation of many of the Cisco professional certifications, and it would be a disservice to you if this book did not help you truly learn the material. Therefore, this book helps you pass the CCNA exam by using the following methods:
■Helping you discover which exam topics you have not mastered
■Providing explanations and information to fill in your knowledge gaps
■Supplying exercises that enhance your ability to recall and deduce the answers to test questions
■Providing practice exercises on the topics and the testing process via test questions on the CD
xxvi
Book Features
To help you customize your study time using these books, the core chapters have several features that help you make the best use of your time:
■“Do I Know This Already?” Quizzes—Each chapter begins with a quiz that helps you determine the amount of time you need to spend studying that chapter. If you follow the directions at the beginning of the chapter, the “Do I Know This Already?” quiz directs you to study all or particular parts of the chapter.
■Foundation Topics—These are the core sections of each chapter. They explain the protocols, concepts, and configuration for the topics in that chapter. If you need to learn about the topics in a chapter, read the “Foundation Topics” section.
■Foundation Summary—Near the end of each chapter, a summary collects the most important information from the chapter, summarized in lists, tables, and figures. The
“Foundation Summary” section is designed to help you review the key concepts in the chapter if you scored well on the “Do I Know This Already?” quiz. This section is an excellent tool for last-minute review.
■Q&A—Each chapter ends with a “Q&A” section that forces you to exercise your recall of the facts and processes described in that chapter. These questions generally are harder than those on the exam, partly because they are in “short answer” format instead of multiple-choice. These questions are a great way to increase the accuracy of your recollection of the facts.
■CD-based practice exam—The companion CD contains a large number of questions not included in the book, as well as all the questions from the “Do I Know This Already” quizzes. You can answer these questions by using the simulated exam feature or the topical review feature. This is the best tool for helping you prepare for the test-taking process.
■Hands-on practice using Boson NetSim™ LE—The CD also includes the Boson NetSim for CCNA ICND Learning Edition network simulator software, supporting the ability to perform many of the commands covered in the book. In particular, you can perform many of the practice scenarios and hands-on lab exercises also included on the CD, as
well as several from the book. Appendix C details how to access the simulator, and what lab exercises can be performed. (The version of the Boson NetSimtm software included with this book is a limited functionality version. In order to access all functions and features of the software, you must purchase a full license for the software from Boson Software, Inc.)
■CD-based practice scenarios—The companion CD contains a CD-only appendix B (which is a totally different appendix as compared with the printed appendix B in the book) which has several practice scenarios. These scenarios include several problem statements, with solutions, in order to help you pull both concepts and configuration commands together. These scenarios are useful for building your hands-on skills, even if you do not have lab gear. You can also perform some of these scenarios using the Boson NetSim LE network simulator, or using your own lab gear.