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Cisco Press • 800 East 96th Street • Indianapolis, Indiana 46240 USA

31 Days Before Your

CCENT Certification

Exam

Second EditionAllan Johnson

ii 31 Days Before Your CCENT Certification Exam

31 Days Before Your CCENT Certification ExamSecond Edition

A Day-By-Day Review Guide for the ICND1 (100-101) Certification Exam

Allan Johnson

Copyright© 2014 Cisco Systems, Inc.

Published by:

Cisco Press

800 East 96th Street

Indianapolis, IN 46240 USA

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any

means, electronic or mechanical, including photocopying, recording, or by any information storage and

retrieval system, without written permission from the publisher, except for the inclusion of brief quota-

tions in a review.

Printed in the United States of America

First Printing December 2013

Library of Congress Control Number: 2013953096

ISBN-13: 978-1-58720-453-1

ISBN-10: 1-58720-453-3

Warning and Disclaimer

This book is designed to provide information about exam topics for the Cisco Certified Entry

Networking Technician (CCENT) Exam 100-101 ICND1. Every effort has been made to make this book

as complete and as accurate as possible, but no warranty or fitness is implied.

The information is provided on an “as is” basis. The authors, Cisco Press, and Cisco Systems, Inc. shall

have neither liability nor responsibility to any person or entity with respect to any loss or damages

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accompany it.

The opinions expressed in this book belong to the author and are not necessarily those of Cisco

Systems, Inc.

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iii

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At Cisco Press, our goal is to create in-depth technical books of the highest quality and value. Each

book is crafted with care and precision, undergoing rigorous development that involves the unique

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iii

About the Author

Allan Johnson entered the academic world in 1999 after ten years as a business owner/operator to dedicate his efforts to his passion for teaching. He holds both an MBA and an M.Ed. in occupational training and development. He taught CCNA courses at the high school level for seven years and has taught both CCNA and CCNP courses at Del Mar College in Corpus Christi, Texas. In 2003, Allan began to commit much of his time and energy to the CCNA Instructional Support Team, providing services to Networking Academy instructors worldwide and creating training materials. He now works full time for Cisco Networking Academy as a learning systems developer.

About the Technical Reviewer

Steve Stiles is a Cisco Networking Academy Instructor for Rhodes State College and a Cisco Certified Instructor Trainer, having earned CCNA Security and CCNP level certifica-tions. He was the recipient of the 2012 Outstanding Teacher of the Year award by the Ohio Association of Two Year Colleges and co-recipient of the Outstanding Faculty of the Year award at Rhodes State College.

iv 31 Days Before Your CCENT Certification Exam

v

Dedication

For my wife, Becky. Without the sacrifices you made during the project, this work would not have come to fruition. Thank you for providing me the comfort and resting place only you can give.

Acknowledgments

When I began to think of whom I would like to have as a technical editor for this work, Steve Stiles immediately came to mind. With his instructor and industry background, as well as his excellent work building activities for the new Cisco Networking Academy cur-riculum, he was an obvious choice. Thankfully, when Mary Beth Ray contacted him, he was willing and able to do the arduous review work necessary to make sure that you get a book that is both technically accurate and unambiguous.

This book is a concise summary of the work of Cisco Press CCNA authors. Wendell Odom’s Cisco CCENT/CCNA ICND1 100-101 Official Cert Guide and Anthony Sequeira’s Interconnecting Cisco Network Devices, Part 1 (ICND1) Foundation Learning

Guide were two of my main sources. The different approaches that these two authors—both CCIEs—take toward the CCNA material gives the reader the breadth and the depth needed to master the CCNA exam topics.

The Cisco Networking Academy authors for the online curriculum and series of Companion Guides take the reader deeper, past the CCNA exam topics, with the ultimate goal of not only preparing the student for CCNA certification, but also for more advanced college-level technology courses and degrees. Thank you especially to Amy Gerrie and her team of authors—Rick Graziani, Wayne Lewis, and Bob Vachon—for their excellent treat-ment of the material; it is reflected throughout this book.

Mary Beth Ray, executive editor, amazes me with her ability to juggle multiple projects at once, steering each from beginning to end. I can always count on her to make the tough decisions. Thank you, Mary Beth, for bringing this project to me.

This is my fifth project with Christopher Cleveland as development editor. His dedication to perfection pays dividends in countless, unseen ways. Thank you again, Chris, for providing me with much needed guidance and support. This book could not be a reality without your persistence.

vi 31 Days Before Your CCENT Certification Exam

vii

Contents at a Glance

Introduction xxiii

Day 31 Network Devices, Components, and Applications 1

Day 30 Networking Models and Data Flow 17

Day 29 Ethernet and Media Access Control 31

Day 28 Switching Concepts and Operation 41

Day 27 Basic Switch Configuration 53

Day 26 VLAN Concepts 63

Day 25 VLAN and Trunking Configuration 71

Day 24 The IPv4 Address 79

Day 23 IPv4 Subnetting and VLSM 85

Day 22 IPv6 Addressing Concepts 95

Day 21 Implementing IPv6 Addressing 109

Day 20 Basic Routing Concepts 117

Day 19 Dynamic Routing Protocols 125

Day 18 Basic Router Configuration: IPv4 133

Day 17 Basic Router Configuration: IPv6 145

Day 16 Static and Default Route Configuration 153

Day 15 Single-Area OSPFv2 169

Day 14 Single-Area OSPFv3 185

Day 13 Inter-VLAN Routing Configuration 195

Day 12 DHCP Configuration 205

Day 11 ACL Concepts 221

Day 10 Basic ACL Configuration 227

Day 9 NAT 237

Day 8 Basic Device Security 249

Day 7 Switch Security Configuration 259

Day 6 Troubleshoot IP Addressing Issues 267

Day 5 Troubleshoot VLAN Issues 273

Day 4 Troubleshoot Trunking Issues 277

Day 3 Troubleshoot ACL Issues 281

Day 2 Troubleshoot Layer 1 Issues 287

Day 1 CCENT Skills Review and Practice 295

Exam Day 307

Post-Exam Information 309

Index 311

viii 31 Days Before Your CCENT Certification Exam

ix

Contents

Introduction xxiii

Day 31: Network Devices, Components, and Applications 1

CCENT 100-101 ICND1 Exam Topics 1

Key Points 1

Devices 1

Switches 2

Routers 3

Physical Layer 4

Network Media Forms and Standards 4

LAN Device Connection Guidelines 6

LANs and WANs 7

Networking Icons 8

Physical and Logical Topologies 8

Cisco Borderless Network 9

Hierarchy in a Borderless Network 10

Network Documentation 11

Classification of Network Applications 12

User Application Interaction 12

Common Network Applications 13

Growth of Network-Based Applications 13

Quality of Service 14

Increased Network Usage 14

The Impact of Voice and Video on the Network 14

Study Resources 15

Day 30: Networking Models and Data Flow 17


Key Points 17

The OSI and TCP/IP Models 17

OSI Layers 18

TCP/IP Layers and Protocols 19

Protocol Data Units and Encapsulation 20

The TCP/IP Application Layer 21

The TCP/IP Transport Layer 22

TCP Header 23

Port Numbers 23

Error Recovery 24

Flow Control 25

Connection Establishment and Termination 25

UDP 26

The TCP/IP Internet Layer 27

The TCP/IP Network Access Layer 27

Data Encapsulation Summary 29

Study Resources 30

Day 29: Ethernet and Media Access Control 31


Key Topics 31

Ethernet Overview 31

Legacy Ethernet Technologies 32

CSMA/CD 33

Legacy Ethernet Summary 34

Current Ethernet Technologies 34

UTP Cabling 34

Benefits of Using Switches 36

Ethernet Addressing 36

Ethernet Framing 37

The Role of the Physical Layer 38

Study Resources 39

Day 28: Switching Concepts and Operation 41


Key Topics 41

Evolution to Switching 41

Switching Logic 42

Collision and Broadcast Domains 43

x 31 Days Before Your CCENT Certification Exam

xi

Frame Forwarding 43

Switch Forwarding Methods 44

Symmetric and Asymmetric Switching 44

Memory Buffering 44

Layer 2 and Layer 3 Switching 44

Accessing and Navigating the Cisco IOS 45

Connecting to Cisco Devices 45

CLI EXEC Sessions 46

Using the Help Facility 46

CLI Navigation and Editing Shortcuts 47

Command History 48

IOS Examination Commands 48

Subconfiguration Modes 49

Storing and Erasing Configuration Files 49

Study Resources 51

Day 27: Basic Switch Configuration 53


Key Topics 53

Basic Switch Configuration Commands 53

Half-Duplex, Full-Duplex, and Port Speed 55

Automatic Medium-Dependent Interface Crossover (auto-MDIX) 56

Configuring SSH Access 56

Verifying Network Connectivity 58

Study Resources 61

Day 26: VLAN Concepts 63


Key Points 63

VLAN Concepts 63

Traffic Types 64

Types of VLANs 65

Voice VLAN Example 65

Trunking VLANs 66

Dynamic Trunking Protocol 68

Study Resources 69

Day 25: VLAN and Trunking Configuration 71


Key Points 71

Sample Topology 71

VLAN Configuration and Verification Commands 72

Configuring and Verifying Trunking 75

Study Resources 78

Day 24: The IPv4 Address 79


Key Topics 79

IPv4 Addressing 79

Header Format 79

Classes of Addresses 80

Purpose of the Subnet Mask 81

Private and Public IP Addressing 82

Study Resources 83

Day 23: IPv4 Subnetting and VLSM 85


Key Topics 85

Subnetting in Four Steps 85

Determine How Many Bits to Borrow 86

Determine the New Subnet Mask 87

Determine the Subnet Multiplier 87

List the Subnets, Host Ranges, and Broadcast Addresses 87

Subnetting Example 1 88



VLSM 89

Summarizing Subnet Addresses 91

Study Resources 93

xii 31 Days Before Your CCENT Certification Exam

xiii

Day 22: IPv6 Addressing Concepts 95


Key Topics 95

Overview and Benefits of IPv6 95

The IPv6 Protocol 96

IPv6 Address Types 97

Unicast 98

Multicast 104

Anycast 106

Study Resources 106

Day 21: Implementing IPv6 Addressing 109


Key Topics 109

Representing the IPv6 Address 109

Conventions for Writing IPv6 Addresses 109

Conventions for Writing IPv6 Prefixes 110

IPv6 Subnetting 111

Subnetting the Subnet ID 111

Subnetting into the Interface ID 112

EUI-64 Concept 112

Stateless Address Autoconfiguration 113

Migration to IPv6 114

Study Resources 115

Day 20: Basic Routing Concepts 117


Key Topics 117

Packet Forwarding 117

Path Determination and Switching Function Example 118

Routing Methods 119

Classifying Dynamic Routing Protocols 120

IGP and EGP 121

Distance Vector Routing Protocols 121

Link-State Routing Protocols 122

xiv 31 Days Before Your CCENT Certification Exam

Classful Routing Protocols 122

Classless Routing Protocols 122

Study Resources 123

Day 19: Dynamic Routing Protocols 125


Key Topics 125

Dynamic Routing Metrics 125

Administrative Distance 126

IGP Comparison Summary 128

Routing Loop Prevention 128

Link-State Routing Protocol Features 129

Building the LSDB 129

Calculating the Dijkstra Algorithm 130

Convergence with Link-State Protocols 131

Study Resources 132

Day 18: Basic Router Configuration: IPv4 133


Key Topic 133

Basic Router Configuration with IPv4 133

Study Resources 142

Day 17: Basic Router Configuration: IPv6 145


Key Topic 145

Basic Router Configuration with IPv6 145

Verifying IPv4 and IPv6 Network Connectivity 148

Study Resources 151

Day 16: Static and Default Route Configuration 153


Key Topics 153

Static and Default Routing Overview 153

xv

IPv4 Static Route Configuration 154

IPv4 Static Routes Using the “Next-Hop” Parameter 156

IPv4 Static Routes Using the Exit Interface Parameter 157

IPv4 Default Route Configuration 158

IPv4 Summary Static Route Configuration 161

IPv6 Static Routing 162

IPv6 Static Route Configuration 164

IPv6 Default Route Configuration 165

IPv6 Summary Static Route Configuration 166

Study Resources 167

Day 15: Single-Area OSPFv2 169


Key Topics 169

OSPF Operation 169

OSPF Message Format 169

OSPF Packet Types 170

Neighbor Establishment 170

Link-State Advertisements 172

OSPF DR and BDR 173

OSPF Algorithm 173

Link-State Routing Process 174

Single-Area OSPFv2 Configuration 175

The router ospf Command 176

The network Command 176

Router ID 177

Passive Interfaces 177

Modifying the OSPF Metric 178

Verifying OSPFv2 180

Study Resources 184

xvi 31 Days Before Your CCENT Certification Exam

Day 14: Single-Area OSPFv3 185


Key Topics 185

OSPFv2 Versus OSPFv3 185

Similarities Between OSPFv2 and OSPFv3 185

Differences Between OSPFv2 and OSPFv3 186

Single-Area OSPFv3 Configuration 186

The Router ID in OSPFv3 188

Verifying OSPFv3 189

Study Resources 192

Day 13: Inter-VLAN Routing Configuration 195


Key Topics 195

Inter-VLAN Routing Concepts 195

Legacy Inter-VLAN Routing 195

Router on a Stick 196

Multilayer Switch 197

Router on a Stick Configuration and Verification 197

Multilayer Switch Inter-VLAN Routing Configuration and Verification 200

Creating Additional SVIs 200

Configuring a 2960 to Route Between VLANs 201

Study Resources 204

Day 12: DHCP Configuration 205


Key Topics 205

DHCPv4 205

DHCPv4 Configuration Options 206

Configuring a Router as a DHCPv4 Server 206

Configuring a Router to Relay DHCPv4 Requests 210

Configuring a Router as a DHCPv4 Client 211

xvii

DHCPv6 212

SLAAC 212

Stateless DHCPv6 214

Stateful DHCPv6 214

Stateless and Stateful DHCPv6 Operation 214

DHCPv6 Configuration Options 216

Configuring a Router as a Stateless DHCPv6 Server 216

Configuring a Router as a Stateful DHCPv6 Server 217

Study Resources 218

Day 11: ACL Concepts 221


Key Topics 221

ACL Operation 221

Defining an ACL 221

Processing Interface ACLs 221

List Logic with IP ACLs 222

Planning to Use ACLs 223

Types of ACLs 224

ACL Identification 225

ACL Design Guidelines 225

Study Resources 226

Day 10: Basic ACL Configuration 227


Key Topics 227

Configuring Standard Numbered ACLs 227

Standard Numbered ACL: Permit Specific Network 228

Standard Numbered ACL: Deny a Specific Host 228

Standard Numbered ACL: Deny a Specific Subnet 229

Standard Numbered ACL: Deny Telnet or SSH Access to the Router 229

Configuring Extended Numbered ACLs 230

Extended Numbered ACL: Deny FTP from Subnets 231

Extended Numbered ACL: Deny Only Telnet from Subnet 231

xviii 31 Days Before Your CCENT Certification Exam

Configuring Named ACLs 231

Standard Named ACL Steps and Syntax 232

Standard Named ACL: Deny a Single Host from a Given Subnet 232

Extended Named ACL Steps and Syntax 233

Adding Comments to Named or Numbered ACLs 233

Verifying ACLs 234

Study Resources 236

Day 9: NAT 237


Key Topics 237

NAT Concepts 237

A NAT Example 239

Dynamic and Static NAT 240

NAT Overload 240

NAT Benefits 241

NAT Limitations 241

Configuring Static NAT 242

Configuring Dynamic NAT 243

Configuring NAT Overload 244

Verifying NAT 245

Troubleshooting NAT 246

NAT for IPv6 247

IPv6 Private Address Space 247

Purpose of NAT for IPv6 247

Study Resources 248

Day 8: Basic Device Security 249


Key Topics 249

Network Security Overview 249

Physical Security 249

Types of Security Vulnerabilities 250

xix

Mitigating Network Attacks 250

Security Best Practices 250

Securing the IOS 251

Passwords, Authentication, Timers, and SSH 251

Banners 253

Disable Services 255

HTTP Service 255

CDP 255

Small Services 256

Network Time Protocol 256

Study Resources 258

Day 7: Switch Security Configuration 259


Key Topics 259

Configuring Port Security 259

Restoring a Port After a Violation 261

Changing the Native and Management VLANs 263

Shutting Down and Securing Unused Interfaces 264

Study Resources 264

Day 6: Troubleshoot IP Addressing Issues 267


Key Topics 267

Troubleshooting Methodology 267

Default Gateway 267

Duplicate IP Addresses 268

DHCP Issues 268

Resolve IPv4 Address Conflicts 268

Test Connectivity Using a Static IP Address 269

Verify Switch Port Configuration 269

Test DHCPv4 Operation on the Same Subnet or VLAN 269

Inter-VLAN Routing and IP Addressing Issues 269

Study Resources 271

xx 31 Days Before Your CCENT Certification Exam

Day 5: Troubleshoot VLAN Issues 273


Key Topics 273

VLAN Troubleshooting 273

Disabled VLANs 274

Study Resources 275

Day 4: Troubleshoot Trunking Issues 277


Key Topics 277

Trunking Troubleshooting Overview 277

Check Both Ends of a Trunk 277

Check Trunking Operational States 278

Study Resources 279

Day 3: Troubleshoot ACL Issues 281


Key Topics 281

Troubleshooting ACLs 281

Problem 1: Host Has No Connectivity 282

Problem 2: Denied Protocols 283

Problem 3: Telnet Is Allowed #1 284



Study Resources 286

Day 2: Troubleshoot Layer 1 Issues 287


Key Topics 287

Media Issues 287

Interface Status and the Switch Configuration 288

Interface Status Codes 288

Duplex and Speed Mismatches 289

Common Layer 1 Problems On “Up” Interfaces 290

CDP as a Troubleshooting Tool 291

Study Resources 293

xxi

Day 1: CCENT Skills Review and Practice 295

Key Topics 295

Introduction 295

Topology Diagram 295

Addressing Table 296

VLANs and Port Assignments Table 296

ISP Configuration 297

Implementation 297

IPv4 Addressing Configuration Requirements 297

HQ-Sw Configuration Requirements 297

HQ Configuration Requirements 298

B1 and B2 Configuration Requirements 298

Staff 299

Verification 299

Your Notes 300

Answer Scripts 302

CCENT Skills Challenge 305

Exam Day 307

What You Need for the Exam 307

What You Should Receive After Completion 307

Summary 308

Post-Exam Information 309

Receiving Your Certificate 309

Determining Career Options 309

Examining Certification Options 310

If You Failed the Exam 310

Summary 310

Index 311

xxii 31 Days Before Your CCENT Certification Exam

Icons Used in This Book

Command Syntax Conventions

The conventions used to present command syntax in this book are the same conventions used in the IOS Command Reference. The Command Reference describes these conventions as follows:

Boldface indicates commands and keywords that are entered literally as shown. In actual configuration examples and output (not general command syntax), boldface indicates commands that are manually input by the user (such as a show command).

Italic indicates arguments for which you supply actual values.

Vertical bars (|) separate alternative, mutually exclusive elements.

Square brackets ([ ]) indicate an optional element.

Braces ({ }) indicate a required choice.

Braces within brackets ([{ }]) indicate a required choice within an optional element.

DesktopComputer

LANMedia

WANMedia

WirelessMedia

Router Multilayer Switch

Laptop Server

IP Phone

LAN Switch

WirelessRouter

Firewall Hub

WirelessAccess Point

xxiii

Introduction

You are almost there! If you’re reading this Introduction, you’ve probably already spent a considerable amount of time and energy pursuing your CCENT certification. Regardless of how you got to this point in your travels through your CCENT studies, 31 Days Before

Your CCENT Certification Exam most likely represents the last leg of your journey on your way to the destination: to become a Cisco Certified Entry Networking Technician. However, if you are like I am, you might be reading this book at the beginning of your studies. If such is the case, this book provides you with an excellent overview of the mate-rial that you must now spend a great deal of time studying and practicing. However, I must warn you: Unless you are extremely well-versed in networking technologies and have con-siderable experience configuring and troubleshooting Cisco routers and switches, this book will not serve you well as the sole resource for CCENT exam preparation. Therefore, let me spend some time discussing my recommendations for study resources.

Study Resources

Cisco Press offers an abundance of CCNA-related books to serve as your primary source for learning how to install, configure, operate, and troubleshoot small- to medium-size routed and switched networks.

Primary ResourcesFirst on the list must be Wendell Odom’s Cisco CCENT/CCNA ICND1 100-101 Official

Cert Guide (ISBN: 9781587143854). If you do not buy any other books, buy this one. Wendell’s method of teaching, combined with his technical expertise and down-to-earth style, is unsurpassed in our industry. As you read through his books, you sense that he is sitting right there next to you walking you through the material. The practice exams and study materials on the DVD in the back of the book are worth the price of the book. There is no better resource on the market for a CCNA candidate.

Next on the list must be Anthony Sequeira’s Interconnecting Cisco Network Devices,

Part 1 (ICND1) Foundation Learning Guide (ISBN: 9781587143762). This book is indis-pensable to those students who take the first of two Cisco-recommended training class for CCNA preparation: Interconnecting Cisco Network Devices 1 (ICND1). These courses, available through Cisco Training Partners in a variety of formats, are usually of a very short duration (one to six weeks) and are geared toward the industry professional already working in the field of networking. Anthony’s book serves the reader well as a concise, but thorough, treatment of the CCENT exam topics. His method and approach often differ and complement Wendell’s approach. I recommend that you also refer to this book.

If you are a Cisco Networking Academy student, you are blessed with access to the online version of the CCNA Routing and Switching curriculum and the wildly popular Packet Tracer network simulator. Although there are currently two paths for the CCNA curriculum, I used the Introduction to Networking (ITN) and Routing and Switching Essential (RSE) courses in my daily review of the exam topics. ITN introduces basic concepts of computer networks, including deep dives into the seven layers of the OSI model, IP addressing, and the fundamentals of Ethernet. Successfully completing the course means that you should be able to build small LANs and implement basic addressing and configurations on routers

xxiv 31 Days Before Your CCENT Certification Exam

and switches. RSE expands on ITN, taking the student further into basic router and switch configuration. Successfully completing the course means that you should be able to config-ure and troubleshoot routers and switches using a variety of technologies including RIPv2, single-area OSPF, VLANs, and inter-VLAN routing for both IPv4 and IPv6 networks. To learn more about CCNA Routing and Switching courses and to find an Academy near you, visit www.netacad.com.

However, if you are not an Academy student but would like to benefit from the extensive authoring done for these courses, you can buy any or all the CCNA Routing and Switching Companion Guides (CG) and Lab Manuals (LM) of the Academy’s popular online cur-riculum. Although you will not have access to the Packet Tracer network simulator soft-ware, you will have access to the tireless work of an outstanding team of Cisco Academy Instructors dedicated to providing students with comprehensive and engaging CCNA prepa-ration course material. The titles and ISBNs for the CCNA Routing and Switching CGs and LMs are as follows:

Introduction to Networks Companion Guide (ISBN: 9781587133169)

Introduction to Networks Lab Manual (ISBN: 9781587133121)

Routing and Switching Essentials Companion Guide (ISBN: 9781587133183)

Routing and Switching Essentials Lab Manual (ISBN: 9781587133206)

You can find these books at www.ciscopress.com by clicking the Cisco Networking Academy link.

Supplemental ResourcesIn addition to the book you hold in your hands, there are four more supplemental resources I recommend to augment your final 31 days of review and preparation.

First, a plug for my own book, the CCENT Practice and Study Guide, Exercises,

Activities and Scenarios to Prepare for the ICND1/CCENT (100-101) Certification

Exam (ISBN: 9781587133459). The subtitle is a concise summary of what you will get. Although an appropriate resource for anyone, this book is specifically geared toward the Cisco Networking Academy instructors and students who want a resource to supplement the online curriculum. Mirroring the chapter layout of the first two online courses, the CCENT PSG offers exercises that help you learn the concepts and configurations that are crucial to your success as a CCENT candidate.

Second, Wendell Odom and Sean Wilkins have created over 250 structured labs that are available in the Cisco CCENT ICND1 100-101 Network Simulator (ISBN: 9780789750433). These simulations map precisely to chapters in his book, but are also a great practice resource for anyone. The four types of labs in this product present you with progressively more difficult real-world challenges. Skill builder labs help you practice short, focused configuration tasks. Subnetting exercises help you improve the speed and accuracy of your subnetting calculations. Complex Configuration Scenario labs present realistic multilayered, multitechnology configuration tasks. Finally, challenging Troubleshooting Scenario labs provide you with an opportunity to test your problem identification and resolution skills. If you need that extra edge or are struggling with a particular configuration or troubleshoot-ing concept, you’ll find these simulations very helpful.

http://www.netacad.com

http://www.ciscopress.com

xxv

Third, Eric Rivard is the author of Cisco CCENT ICND1 100-101 Flash Cards and Exam

Practice Pack (ISBN: 9781587203992). The text portion of the book includes over 450 flash cards that quickly review exam topics in bite-sized pieces. Also included is over 100 pages in the Quick Reference Guide, which is designed for late-stage exam preparation. And on the included CD, you will find a test engine with over 150 CCENT practice exam ques-tions.

NOTE: If you are certain that you will be also pursuing your CCNA certification, the more economical purchase might be to buy the Cisco CCNA Routing and Switching 200-120

Flash Cards and Exam Practice Pack (ISBN: 9781587204005). The first half of this book is a repeat of the CCENT version.

Fourth, there is Scott Empson’s very popular CCNA Routing and Switching Portable

Command Guide, Third Edition (ISBN: 9781587204302). This guide is way more than just a listing of commands and what they do. Yes, it summarizes all the CCNA certification-level IOS commands, keywords, command arguments, and associated prompts. But it also pro-vides you with tips and examples of how to apply the commands to real-world scenarios. Configuration examples throughout the book provide you with a better understanding of how these commands are used in simple network designs.

The Cisco Learning NetworkFinally, if you have not done so already, you should now register with The Cisco Learning Network at https://learningnetwork.cisco.com. Sponsored by Cisco, The Cisco Learning Network is a free social learning network where IT professionals can engage in the common pursuit of enhancing and advancing their IT careers. Here you will find many resources to help you prepare for your CCNA exam as well as a community of like-minded people ready to answer your questions, help you with your struggles, and share in your triumphs.

So which resources should you buy? That question is largely up to how deep your pockets are or how much you like books. If you’re like I am, you must have it all! I admit it. My bookcase is a testament to my Cisco “geekness.” But if you are on a budget, choose one of the primary study resources and one of the supplemental resources, such as Wendell Odom’s certification book and my practice study guide. Whatever you choose, you will be in good hands. Any or all of these authors will serve you well.

Goals and Methods

The main goal of this book is to provide you with a clear and succinct review of the CCENT objectives. Each day’s exam topics are grouped into a common conceptual frame-work and use the following format:

A title for the day that concisely states the overall topic

A list of one or more CCENT 100-101 ICND1 Exam Topics to be reviewed

A Key Topics section to introduce the review material and quickly orient you to the day’s focus

An extensive review section consisting of short paragraphs, lists, tables, examples, and graphics

https://learningnetwork.cisco.com

xxvi 31 Days Before Your CCENT Certification Exam

A Study Resources section to provide you with a quick reference for locating more in-depth treatment of the day’s topics

The book counts down starting with Day 31 and continues through exam day to provide post-test information. You will also find a calendar and checklist that you can tear out and use during your exam preparation inside the book.

Use the calendar to enter each actual date beside the countdown day and the exact day, time, and location of your CCENT exam. The calendar provides a visual for the time that you can dedicate to each CCENT exam topic.

The checklist highlights important tasks and deadlines leading up to your exam. Use it to help you map out your studies.

Who Should Read This Book

The audience for this book is anyone finishing his or her preparation for taking the CCENT 100-101 ICND1 exam. A secondary audience is anyone needing a refresher review of CCENT exam topics—possibly before attempting to recertify or sit for another certifica-tion to which the CCNA is a prerequisite.

Getting to Know the CCENT 100-101 ICND1 Exam

For the current certifications, announced in spring 2013, Cisco created the ICND1 (100-101) and ICND2 (200-101) exams, along with the CCNA (200-120) exam. To become CCENT certified, you only need to pass the ICND1 exam. To become CCNA Routing and Switching certified, you must pass both the ICND1 and ICND2 exams, or just the CCNA exam. The CCNA exam simply covers all the topics of the ICND1 and ICND2 exams, giving you two options for gaining your CCNA Routing and Switching certification. The two-exam path gives people with less experience a chance to study for a smaller set of topics at one time. The one-exam option provides a more cost-effective certification path for those who want to prepare for all the topics at once. This book focuses exclusively on the CCENT path, using the entire list of topics published for the CCENT 100-101 ICND1 exam.

Currently for the CCENT exam, you are allowed 90 minutes to answer 50–60 questions. Use the following steps to access a tutorial at home that demonstrates the exam environ-ment before you go to take the exam:

Step 1. Visit www.vue.com/cisco.

Step 2. Look for a link to the certification tutorial. Currently, it can be found on the right side of the web page under the heading “Related Links.”

Step 3. Click the certification tutorial link.

When you get to the testing center and check in, the proctor verifies your identity, gives you some general instructions and then takes you into a quiet room containing a PC. When you’re at the PC, you have a few things to do before the timer starts on your exam. For instance, you can take the tutorial to get accustomed to the PC and the testing engine. Every time I sit for an exam, I go through the tutorial even though I know how the test

http://www.vue.com/cisco

xxvii

engine works. It helps me settle my nerves and get focused. Anyone who has user-level skills in getting around a PC should have no problems with the testing environment.

When you start the exam, you are asked a series of questions. Each question is presented one at a time and must be answered before moving on to the next question. The exam engine does not let you go back and change your answer. The exam questions can be in one of the following formats:

Multiple choice

Fill-in-the-blank

Drag-and-drop

Testlet

Simlet

Simulation

The multiple-choice format simply requires that you point and click a circle or check box next to the correct answer or answers. Cisco traditionally tells you how many answers you need to choose, and the testing software prevents you from choosing too many or too few.

Fill-in-the-blank questions typically only require you to type numbers. However, if words are requested, the case does not matter unless the answer is a command that is case sensi-tive (such as passwords and device names when configuring authentication).

Drag-and-drop questions require you to click and hold, move a button or icon to another area, and release the mouse button to place the object somewhere else—typically in a list. For some questions, to get the question correct, you might need to put a list of five things in the proper order.

Testlets contain one general scenario and several multiple-choice questions about the sce-nario. These are ideal if you are confident in your knowledge of the scenario’s content because you can leverage your strength over multiple questions.

A simlet is similar to a testlet in that you are given a scenario with several multiple-choice questions. However, a simlet uses a network simulator to allow you access to a simulation of the command line of Cisco IOS Software. You can then use show commands to examine a network’s current behavior and answer the question.

A simulation also uses a network simulator, but you are given a task to accomplish such as implementing a network solution or troubleshooting an existing network implementation. You do this by configuring one or more routers and switches. The exam then grades the question based on the configuration you changed or added. A newer form of the simula-tion question is the GUI-based simulation, where a graphical interface like that found on a Linksys router or the Cisco Security Device Manager are simulated.

xxviii 31 Days Before Your CCENT Certification Exam

What Topics Are Covered on the CCENT Exam?The topics of the CCENT 100-101 ICND1 exam focus on the following seven key catego-ries:

Operation of IP Data Networks

LAN Switching Technologies

IP Addressing for IPv4 and IPv6

IP Routing Technologies

IP Services

Network Device Security

Troubleshooting

Although Cisco outlines general exam topics, it is possible that not all topics will appear on the CCENT exam and that topics that are not specifically listed might appear on the exam. The exam topics provided by Cisco and included in this book are a general framework for exam preparation. Be sure to check the Cisco website for the latest exam topics.

Registering for the CCENT 100-101 ExamIf you are starting your 31 Days to Your CCENT Certification Exam today, register for the exam right now. In my testing experience, there is no better motivator than a scheduled test date staring me in the face. I’m willing to bet that it’s the same for you. Don’t worry about unforeseen circumstances. You can cancel your exam registration for a full refund up to 24 hours before taking the exam. So if you’re ready, you should gather the following information in Table I-1 and register right now!

Table I-1 Personal Information for CCENT 100-101 ICND1 Exam Registration

Item Notes

Legal Name

Social Security or Passport Number

Cisco Certification ID or Test ID1

Cisco Academy Username2

Cisco Academy ID Number2

Company Name

Valid Email Address

Voucher Number2

Method of Payment

1Applies to exam candidates who have previously taken a Cisco certification exam

2Applies to Cisco Networking Academy students only

xxix

To register for an exam, visit Pearson VUE online at www.vue.com/cisco. The process and available test times will vary based on the local testing center you choose.

Remember, there is no better motivation for study than an actual test date. Sign up today.

http://www.vue.com/cisco

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Day 29Ethernet and Media Access Control

CCENT 100-101 ICND1 Exam Topics Determine the technology and media access control method for Ethernet networks.

Key Topics

Ethernet has continued to evolve from the 10BASE2 flavor, capable of speeds up to 10Mbps, to the newest 10GigE (10 Gigabit Ethernet), capable of speeds up to 10Gbps. Since 1985, the IEEE has continued to upgrade the 802.3 standards to provide faster speeds without changing the underlying frame structure. This feature, among others, has made Ethernet the choice for LAN implementations worldwide. Today we review Ethernet tech-nologies and operation at both the data link and physical layers.

Ethernet Overview

802.3 is the IEEE standard for Ethernet, and both terms are commonly used interchange-ably. The terms Ethernet and 802.3 both refer to a family of standards that together define the physical and data link layers of the definitive LAN technology. Figure 29-1 shows a comparison of Ethernet standards to the OSI model.

Figure 29-1 Ethernet Standards and the OSI Model

Data LinkLayer

PhysicalLayer

PhysicalLayer

LLCSublayer

MACSublayer

Eth

erne

t

IEE

E 8

02.3

(Eth

erne

t)

IEE

E 8

02.3

u(F

astE

ther

net)

IEE

E 8

02.3

z(G

igab

itEth

erne

t)

IEE

E 8

02.3

ab(G

igab

itEth

erne

t ove

r C

oppe

r)

Toke

n R

ing/

iEE

E 8

02.6

FD

DI

IEEE 802.2

OSI Layers LAN Specification

Ethernet separates the functions of the data link layer into two distinct sublayers:

Logical Link Control (LLC) sublayer: Defined in the 802.2 standard

Media Access Control (MAC) sublayer: Defined in the 802.3 standard

32 31 Days Before Your CCENT Certification Exam

The LLC sublayer handles communication between the network layer and the MAC sub-layer. In general, LLC provides a way to identify the protocol that is passed from the data link layer to the network layer. In this way, the fields of the MAC sublayer are not popu-lated with protocol type information, as was the case in earlier Ethernet implementations.

The MAC sublayer has two primary responsibilities:

Data encapsulation: Includes frame assembly before transmission, frame parsing upon reception of a frame, data link layer MAC addressing, and error detection.

Media Access Control: Because Ethernet is a shared media and all devices can trans-mit at any time, media access is controlled by a method called Carrier Sense Multiple Access with Collision Detection (CSMA/CD) when operating in half-duplex mode.

At the physical layer, Ethernet specifies and implements encoding and decoding schemes that enable frame bits to be carried as signals across both unshielded twisted-pair (UTP) copper cables and optical fiber cables. In early implementations, Ethernet used coaxial cabling.

Legacy Ethernet Technologies

Ethernet is best understood by first considering the two early Ethernet specifications—10BASE5 and 10BASE2. With these two specifications, the network engineer installs a series of coaxial cables connecting each device on the Ethernet network, as shown in Figure 29-2.

Figure 29-2 Ethernet Physical and Logical Bus Topology

TopologyPhysical: BusLogical: Bus

The series of cables creates an electrical circuit, called a bus, which is shared among all devices on the Ethernet. When a computer wants to send some bits to another computer on the bus, it sends an electrical signal and the electricity propagates to all devices on the Ethernet.

With the change of media to UTP and the introduction of the first hubs, Ethernet physical topologies migrated to a star, as shown in Figure 29-3.

Day 29 33

Figure 29-3 Ethernet Physical Star and Logical Bus Topology

TopologyPhysical: StarLogical: Bus

Hub

Regardless of the change in the physical topology from a bus to a star, hubs logically oper-ate similarly to a traditional bus topology and require the use of CSMA/CD.

CSMA/CD

Because Ethernet is a shared media where every device has the right to send at any time, it also defines a specification for how to ensure that only one device sends traffic at a time. The CSMA/CD algorithm defines how the Ethernet logical bus is accessed.

CSMA/CD logic helps prevent collisions and also defines how to act when a collision does occur. The CSMA/CD algorithm works like this:

1. A device with a frame to send listens until the Ethernet is not busy.

2. When the Ethernet is not busy, the sender(s) begin(s) sending the frame.

3. The sender(s) listen(s) to make sure that no collision occurred.

4. If a collision occurs, the devices that had been sending a frame each send a jamming signal to ensure that all stations recognize the collision.

5. After the jamming is complete, each sender randomizes a timer and waits that long before trying to resend the collided frame .

6. When each random timer expires, the process starts again from the beginning.

When CSMA/CD is in effect, it also means that a device’s network interface card (NIC) is operating in half-duplex mode—either sending or receiving frames. CSMA/CD is disabled when a NIC autodetects that it can operate in—or is manually configured to operate in—full-duplex mode. In full-duplex mode, a NIC can send and receive simultaneously .


Legacy Ethernet Summary

Today , you might occasionally use LAN hubs, but you will more likely use switches instead of hubs. However, keep in mind the following key points about the history of Ethernet:

The original Ethernet LANs created an electrical bus to which all devices connected.

10BASE2 and 10BASE5 repeaters extended the length of LANs by cleaning up the electrical signal and repeating it—a Layer 1 function—but without interpreting the meaning of the electrical signal.

Hubs are repeaters that provide a centralized connection point for UTP cabling—but they still create a single electrical bus, shared by the various devices, just like 10BASE5 and 10BASE2.

Because collisions could occur in any of these cases, Ethernet defines the CSMA/CD algorithm, which tells devices how to both avoid collisions and take action when colli-sions do occur.

Current Ethernet Technologies

Refer to Figure 29-1 and notice the different 802.3 standards. Each new physical layer stan-dard from the IEEE requires many differences at the physical layer. However, each of these physical layer standards uses the same 802.3 header, and each uses the upper LLC sublayer as well. Table 29-1 lists today’s most commonly used IEEE Ethernet physical layer stan-dards.

Table 29-1 Today’s Most Common Types of Ethernet

Common Name Speed Alternative Name Name of IEEE

Standard

Cable Type,

Maximum Length

Ethernet 10Mbps 10BASE-T 802.3 Copper, 100 m

Fast Ethernet 100Mbps 100BASE-TX 802.3u Copper, 100 m

Gigabit Ethernet 1000Mbps 1000BASE-LX 802.3z Fiber, 550 m

Gigabit Ethernet 1000Mbps 1000BASE-T 802.3ab Copper, 100 m

10GigE (Gigabit Ethernet)

10Gbps 10GBASE-T 802.3an Copper, 100 m

UTP Cabling

The three most common Ethernet standards used today— 10BASE-T (Ethernet), 100BASE-TX (Fast Ethernet, or FE), and 1000BASE-T (Gigabit Ethernet, or GE)—use UTP cabling. Some key differences exist, particularly with the number of wire pairs needed in each case and in the type (category) of cabling.

Day 29 35

The UTP cabling used by popular Ethernet standards includes either two or four pairs of wires. The cable ends typically use an RJ-45 connector. The RJ-45 connector has eight spe-cific physical locations into which the eight wires in the cable can be inserted, called pin positions or, simply, pins.

The Telecommunications Industry Association (TIA) and the Electronics Industry Alliance (EIA) define standards for UTP cabling, color-coding for wires, and standard pinouts on the cables. Figure 29-4 shows two TIA/EIA pinout standards, with the color-coding and pair numbers listed.

Figure 29-4 TIA/EIA Standard Ethernet Cabling Pinouts

Pair 2

Pinouts1 = G/W2 = Green3 = O/W4 = Blue5 = Blue/W6 = Orange7 = Brown/W8 = Brown

Pinouts1 = O/W2 = Orange3 = G/W4 = Blue5 = Blue/W6 = Green7 = Brown/W8 = Brown

Pair 3 Pair 1 Pair 4

1 2 3 4 5 6 7 8

T568A

Pair 3

Pair 2 Pair 1 Pair 4

1 2 3 4 5 6 7 8

T568B

For the exam, you should be well prepared to choose which type of cable (straight-through or crossover) is needed in each part of the network. In short, devices on opposite ends of a cable that use the same pair of pins to transmit need a crossover cable. Devices that use an opposite pair of pins to transmit need a straight-through cable. Table 29-2 lists typical devices and the pin pairs they use, assuming that they use 10BASE-T and 100BASE-TX.

Table 29-2 10BASE-T and 100BASE-TX Pin Pairs Used

Devices That Transmit on 1,2 and Receive on 3,6 Devices That Transmit on 3,6

and Receive on 1,2

PC NICs Hubs

Routers Switches

Wireless access points (Ethernet interfaces) —

Networked printers (printers that connect directly to the LAN) —

1000BASE-T requires four wire pairs because Gigabit Ethernet transmits and receives on each of the four wire pairs simultaneously.

However, Gigabit Ethernet does have a concept of straight-through and crossover cables, with a minor difference in the crossover cables. The pinouts for a straight-through cable are the same—pin 1 to pin 1, pin 2 to pin 2, and so on. The crossover cable crosses the same two-wire pair as the crossover cable for the other types of Ethernet—the pair at pins 1,2 and 3,6—as well as crossing the two other pairs (the pair at pins 4,5 with the pair at pins 7,8).


Benefits of Using Switches

A collision domain is a set of devices whose frames could collide. All devices on a 10BASE2, 10BASE5, or any network using a hub risk collisions between the frames that they send, so all devices on one of these types of Ethernet networks are in the same colli-sion domain and use CSMA/CD to detect and resolve collisions.

LAN switches significantly reduce, or even eliminate, the number of collisions on a LAN. Unlike hubs, switches do not create a single shared bus. Instead, switches do the following:

They interpret the bits in the received frame so that they can typically send the frame out the one required port, rather than all other ports.

If a switch needs to forward multiple frames out the same port, the switch buffers the frames in memory, sending one at a time, thereby avoiding collisions.

In addition, switches with only one device cabled to each port of the switch allow the use of full-duplex operation. Full-duplex means that the NIC can send and receive concurrently, effectively doubling the bandwidth of a 100Mbps link to 200Mbps—100Mbps for sending and 100Mbps for receiving.

These seemingly simple switch features provide significant performance improvements as compared with using hubs. In particular:

If only one device is cabled to each port of a switch, no collisions can occur.

Devices connected to one switch port do not share their bandwidth with devices con-nected to another switch port. Each has its own separate bandwidth, meaning that a switch with 100Mbps ports has 100Mbps of bandwidth per port.

Ethernet Addressing

The IEEE defines the format and assignment of LAN addresses. To ensure a unique MAC address, the first half of the address identifies the manufacturer of the card. This code is called the organizationally unique identifier (OUI) . Each manufacturer assigns a MAC address with its own OUI as the first half of the address. The second half of the address is assigned by the manufacturer and is never used on another card or network interface with the same OUI. Figure 29-5 shows the structure of a unicast Ethernet address.

Figure 29-5 Structure of a Unicast Ethernet Address

24 Bits 24 Bits

6 Hex Digits 6 Hex Digits

00 60 2F 3A 07 BC

Organizationally UniqueIdentifier (OUI)

Vendor Assigned(NIC Cards, Interfaces)

Size, in bits

Size, in hex digits

Example

Day 29 37

Ethernet also has group addresses, which identify more than one NIC or network interface. The IEEE defines two general categories of group addresses for Ethernet:

Broadcast addresses: The broadcast address implies that all devices on the LAN should process the frame and has a value of FFFF.FFFF.FFFF.

Multicast addresses: Multicast addresses are used to allow a subset of devices on a LAN to communicate. When IP multicasts over an Ethernet, the multicast MAC addresses used by IP follow this format: 0100.5exx.xxxx. The xx.xxxx por-tion is divided between IPv4 multicast (00:0000–7F.FFFF) and MPLS multicast (80:0000–8F:FFFF). Multiprotocol Label Switching (MPLS) is a CCNP topic.

Ethernet Framing

The physical layer helps you get a string of bits from one device to another. The framing of the bits allows the receiving device to interpret the bits. The term framing refers to the defi-nition of the fields assumed to be in the data that is received. Framing defines the meaning of the bits transmitted and received over a network.

The framing used for Ethernet has changed a couple of times over the years. Each iteration of Ethernet is shown in Figure 29-6, with the current version shown at the bottom.

Figure 29-6 Ethernet Frame Formats

Preamble7

SFD1

Destination6

Source6

Length2

Data and Pad46 – 1500

FCS4

IEEE 802.3 (Original)

Preamble8

Destination6

Source6

Type2


FCS4

DIX

Preamble7

SFD1

DestinationBytes 6

Source6

Length/Type 2


FCS4

IEEE 802.3 (Revised 1997)

The fields in the last version shown in Figure 29-6 are explained further in Table 29-3.


Table 29-3 IEEE 802.3 Ethernet Field Descriptions

Field Field Length

in Bytes

Description

Preamble 7 Synchronization

Start Frame Delimiter (SFD) 1 Signifies that the next byte begins the Destination MAC field

Destination MAC Address 6 Identifies the intended recipient of this frame

Source MAC Address 6 Identifies the sender of this frame

Length 2 Defines the length of the data field of the frame (either length or type is present, but not both)

Type 2 Defines the type of protocol listed inside the frame (either length or type is present, but not both)

Data and Pad 46–1500 Holds data from a higher layer, typically a Layer 3 PDU (generic), and often an IP packet

Frame Check Sequence (FCS)

4 Provides a method for the receiving NIC to determine whether the frame experienced transmission errors

The Role of the Physical LayerWe have already discussed the most popular cabling used in LANs—UTP. But to fully understand the operation of the network, you should know some additional basic concepts of the physical layer.

The OSI physical layer accepts a complete frame from the data link layer and encodes it as a series of signals that are transmitted onto the local media.

The delivery of frames across the local media requires the following physical layer elements:

The physical media and associated connectors

A representation of bits on the media

Encoding of data and control information

Transmitter and receiver circuitry on the network devices

There are three basic forms of network media on which data is represented:

Copper cable

Fiber

Wireless (IEEE 802.11)

Bits are represented on the medium by changing one or more of the following characteris-tics of a signal:

Amplitude

Frequency

Phase

Day 29 39

The nature of the actual signals representing the bits on the media will depend on the signaling method in use. Some methods might use one attribute of a signal to represent a single 0 and use another attribute of a signal to represent a single 1. The actual signaling method and its detailed operation are not important to your CCNA exam preparation.

Study Resources

For today’s exam topics, refer to the following resources for more study.

Resource Location Topic

Primary Resources

Network Basics 10 All

Introduction to Networks 5 All

ICND1 Official Cert Guide 2 Building Physical Ethernet Networks with UTP

Sending Data in Ethernet Networks

ICND1 Foundation Learning Guide 3 All

Supplemental Resources

CCENT Practice and Study Guide 5 All

Flash Cards 3 Relevant Questions

CCNA R&S Portable Command Guide 4 All

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Index

Symbols

10BASE-T, 34-35

10GigE (Gigabit Ethernet), 34

100BASE-TX, 34-35

802.3 standards, 34

1000BASE-T, 34-35

2960 Catalyst switch configuration, 201-203

A

access control lists. See ACLs

access layer switches, 2

access-list command, 228

accessing Cisco IOS

CLI EXEC sessions, 46

CLI navigation and editing shortcuts, 47-48

command history, 48

connecting to Cisco devices, 45-46

help, 46

IOS examination commands, 48

subconfiguration modes, 49

ACLs (access control lists)

defining, 221

design guidelines, 225-226

extended numbered ACLs, configuring, 230-231

identifying, 225

interface processing, 221-222

matching logic, 222-223

named ACLs, configuring, 231-233

standard numbered ACLs, configuring, 227-230

troubleshooting, 281

denied protocols, 283-284

host connectivity issues, 282-283

Telnet, 284-286

types of, 224

verifying, 234-235

AD (administrative distance), 126-127

Address Resolution Protocol (ARP), 20

addresses. See IPv4 addressing; IPv6 addressing

addressing table for CCENT skills review, 296

administrative distance (AD), 126-127

any keyword, 229

anycast addresses, 106

Application layer (OSI), 18

application layer (TCP/IP), 19-21

applications

batch applications, 12

common network applications, 13

growth of, 13

increased network usage, 14

quality of service (QoS), 14

Video over IP, 15

Voice over IP (VoIP), 14-15

interactive applications, 12

real-time applications, 12

user interactions, 12

area keyword, 176

ARP (Address Resolution Protocol), 20

ARPANET, 18

assigned multicast addresses, 104

assigning VLANs to interfaces, 73-75

asymmetric switching, 44

attacks, mitigating, 250

authentication, 251-253

Index

312 auto-cost reference-bandwidth command

auto-cost reference-bandwidth com-mand, 179, 188

automatic medium-dependent interface crossover (auto-MDIX), 56

auto-MDIX (automatic medium-depen-dent interface crossover), 56

AUX ports, 3

B

B1 configuration requirements, 298-299

B2 configuration requirements, 298-299

backup designated routers (BDR), 173

bandwidth command, 179

banner command, 254

banner login command, 54

banner motd command, 54, 135

banners, 253-255


BDR (backup designated routers), 173

bidirectional, 55

bits to borrow, determining, 86

black hole VLANs, 65

broadcast addresses, 37, 87

broadcast domains, 43

buffering memory, 44

Building Your I.T. Career: A Complete Toolkit for a Dynamic Career in Any Economy (Moran), 309

C

cables (UTP), 34-35

Catalyst 2960 switch configuration, 201-203

CDP (Cisco Discovery Protocol)

disabling, 255

as troubleshooting tool, 291-292

certificates

adding to resumes, 309

certificate support website, 309

certification options, 310

receiving, 309

certified score reports, 307

choosing switches, 2

Cisco Borderless Network, 9-11

Cisco Discovery Protocol (CDP), dis-abling, 255

Cisco IOS, accessing


CLI navigation and editing shortcuts, 47-48

command history, 48


help, 46



classes of addresses, 80-81

classful routing protocols, 122

classless routing protocols, 122-123

clear interface command, 140

clear ip nat translation command, 245

CLI (command-line interface), 41

EXEC sessions, 46

navigation and editing shortcuts, 47-48

clients

client-server interaction, 12

DHCPv4 client configuration, 211-212

collusion domains, 43

command history, 48

command-line interface. See CLI

configuration 313

commands. See specific commands

comments, adding to ACLs (access con-trol lists), 233


configuration

B1 and B2 configuration requirements, 298-299

Catalyst 2960 switches, 201-203

configuration files, storing and erasing, 49-50

DHCPv4, 206

DHCPv4 clients, 211-212

DHCPv4 servers, 206-210

relaying DHCPv4 requests, 210-211

DHCPv6

stateful DHCPv6 servers, 217-218

stateless DHCPv6 servers, 216-217

dynamic NAT (Network Address Translation), 243-244

extended numbered ACLs, 230-231

HQ configuration requirements, 298

HQ-Sw configuration requirements, 297-298

IPv4 addressing

configuration requirements, 297

default routing, 158-161

static routing, 154-158

summary static routing, 161-162

IPv4 routers, 133-135

banner motd command, 135

command syntax, 134

copy run start command, 136

copy running-config startup-config command, 136

enable secret class command, 135

hostname command, 135

interface status codes, 137-138

service-password encryption com-mand, 135

show interface command, 138-142

show ip interface brief command, 137

show ip route command, 136-137

show running-config command, 136

IPv6 addressing

default routing, 165


summary static routing, 166-167

IPv6 routers

EUI-64 method, 146

full IPv6 address and link-local address configuration, 146-147

ipv6 unicast-routing command, 145-146

network connectivity, verifying, 148-151

show ipv6 interface command, 147-148

ISPs for CCENT skills review, 297

multilayer switches, 200-203

named ACLs, 231-233

NAT overloading, 244

native and management VLANs, 263

OSPFv2, 175-180

OSPFv3, 186-187

port security, 259-261

router on a stick, 197-200

SSH (Secure Shell), 56-57

standard numbered ACLs, 227

denying specific host, 228-229

denying specific subnet, 229

denying Telnet or SSH access to router, 229-230

permitting specific network, 228

static NAT (Network Address Translation), 242

switches


314 configuration

basic switch configuration com-mands, 53-55

full-duplex communication, 55

half-duplex communication, 55


port speed, 55

SSH (Secure Shell) access, 56-57

switch ports, verifying, 269

VLANs

default configuration, 72

trunking, 75-78

configuration files, storing and erasing, 49-50

configure terminal command, 49, 53

connectionless protocols, 26

connectivity, verifying, 58-61

console ports, 3

convergence with link-state protocols, 131

copper cable, 4-5


copy running-config startup -config command, 54, 136

core layer switches, 2-3

crypto key generate rsa command, 57

crypto key zeroize rsa command, 57

CSMA/CD algorithm, 33

cut-through switching, 44

D

DAD (Duplicate Address Detection), 105, 212

DARPA (Defense Advanced Research Projects Agency), 18

data encapsulation, 29

Data link layer (OSI), 19

data VLANs, 65

database description (DBD) packets, 170

DBD (database description) packets, 170

debug ip nat command, 246

default administrative distances, 127

default gateways, troubleshooting, 267-268

default-router command, 207

default routing

IPv4 configuration, 158-161

IPv6 configuration, 165

overview, 153-154

default VLANs

configuration, 72

explained, 65

Defense Advanced Research Projects Agency (DARPA), 18

defining ACLs (access control lists), 221

denied protocols, troubleshooting, 283-284

deny statement, 231

denying

FTP from subnets, 231

hosts, 228-229, 232

SSH access, 229-230

subnets, 229

Telnet, 229-231

designated routers (DR), 173

designing ACLs (access control lists), 225-226

determining

how many bits to borrow (subnets), 86

subnet masks, 87

subnet multiplier, 87

dynamic NAT (Network Address Translation) 315

device security

IOS security

banners, 253-255

passwords, 251-253

network security

attack mitigation, 250

best practices, 250

physical security, 249

types of vulnerabilities, 250

NTP (Network Time Protocol), 256-257

services, disabling

Cisco Discovery Protocol (CDP), 255

HTTP, 255

small services, 256

DHCPACK packets, 206

DHCPDISCOVER packets, 205, 210

DHCPNAK packets, 206

DHCPOFFER packets, 205

DHCPREQUEST packets, 206

DHCPv4, 13, 20, 205

configuration options, 206

DHCPv4 clients, 211-212

DHCPv4 servers, 206-210


IP addresses, obtaining, 205-206

testing, 269

troubleshooting, 268-269

DHCPv6, 113

ADVERTISE messages, 215

configuration options

stateful DHCPv6 servers, 217-218

stateless DHCPv6 servers, 216-217

INFORMATION-REQUEST messages, 215

operation, 214-215

REQUEST messages, 215

SLAAC, 212-214

SOLICIT messages, 215

stateful DHCPv6, 214

stateless DHCPv6, 214

Dijkstra Shortest Path First (SPF) algo-rithm, 130-131

disabled VLANs, troubleshooting, 274-275

disabling

services


HTTP, 255

small services, 256

VLANs, 274-275

distance vector routing protocols, 121-122

distribution layer switches, 2

DNS (Domain Name System), 13, 19

dns-server command, 207

documentation, 11-12

domain-name command, 207

Domain Name System (DNS), 13, 19

domains, 43

dot1q keyword, 198

double colon (::) in IPv6 routing, 165

DR (designated routers), 173

DROTHER routers, 173

DTP (Dynamic Trunking Protocol), 68

dual-stacking, 114

duplex auto command, 53

duplex mismatches, 289-290

Duplicate Address Detection (DAD), 105, 212

duplicate IP addresses, troubleshooting, 268

Dynamic Host Configuration Protocol. See DHCP

dynamic NAT (Network Address Translation), 240, 243-244

316 dynamic routing protocols

dynamic routing protocols, 119-120

dynamic routing metrics, 125-126

link-state routing protocols

convergence, 131

Dijkstra Shortest Path First (SPF) algorithm, 130-131

link-state database (LSDB), build-ing, 129

routing loop prevention, 128-129

Dynamic Trunking Protocol (DTP), 68

E

EGP (exterior gateway protocols), 121

eHWIC (enhanced high-speed WAN interface card) slots, 3

EIA (Electronics Industry Alliance), 35

EIGRP, 128

Electronics Industry Alliance (EIA), 35

enable password cisco command, 54

enable password command, 55, 251

enable secret class command, 54, 135

enable secret command, 251

enabling VLANs, 274-275

encapsulation command, 198

encapsulation process, 20-21

end command, 54

enhanced high-speed WAN interface card (eHWIC) slots, 3

erase nvram command, 50

erase startup-config command, 50

erasing configuration files, 49-50

error recovery, 24-25

Ethernet

addressing, 36-37

common Ethernet technologies, 34

CSMA/CD algorithm, 33

explained, 20, 31-32

framing, 37-38

legacy Ethernet technologies, 32-34

physical layer, 38-39

switches, 36

UTP cabling, 34-35

EUI-64, 112, 146

evolution to switching, 41-42

exams

certified score reports, 307

exam day requirements, 307

post-exam information

adding certificates to resumes, 309-310



failing exams, 310

receiving certificates, 309

skills review and practice, 295

addressing table, 296

answer scripts, 302-305

B1 and B2 configuration require-ments, 298-299


HQ-Sw configuration require-ments, 297-298

IPv4 addressing configuration requirements, 297

ISP configuration, 297

skills challenge, 305

topology diagram, 295

verification, 299

VLANs and port assignments table, 296

Exec banner, 253

EXEC sessions, 46

exit command, 53-54

exit interface parameter (IPv4 static routing), 157-158

HTTP (Hypertext Transfer Protocol) 317

extended ACLs (access control lists), 224

extended numbered ACLs (access con-trol lists), configuring, 230-231

Extended Unique Identifier (EUI), 112

exterior gateway protocols (EGP), 121

F

failing exams, 310

Fast Ethernet, 34

FDDI (Fiber Distributed Data Interface), 9

Fiber Distributed Data Interface (FDDI), 9

fiber-optic cable, 4-5

File Transfer Protocol (FTP), 13, 20

files (configuration files), storing and erasing, 49-50

flow control, 25

forwarding frames, 43-44

forwarding packets

explained, 117

path determination and switching func-tion example, 118-119

fragment free switching, 44

frame forwarding, 43-44

Frame Relay, 20

framing, 37-38

FTP (File Transfer Protocol), 13, 20

denying, 231

FTTP (Hypertext Transfer Protocol), 13


G

gateways, troubleshooting, 267-268

Gigabit Ethernet, 34

global unicast addresses, 98-101

Graziani, Rick, 95

growth of network applications, 13



Video over IP, 15


H


headers

IPv4 addressing, 79-80

link header, 29

TCP headers, 23

Hello packets, 170-172

help, Cisco IOS, 46

hierarchical network design, 10-11

hold-down timers, 128

hop count, 125

host keyword, 229

host ranges, listing, 87

hostname command, 53, 135

hosts

connectivity issues, troubleshooting, 282-283

denying, 228-229, 232

hot keys, 47-48



HTTP (Hypertext Transfer Protocol), 13, 20

disabling, 255

318 ICMP (Internet Control Message Protocol)

I

ICMP (Internet Control Message Protocol), 20

icons, 8

identifying ACLs (access control lists), 225

IDs

interface IDs, 112

subnet IDs, 111-112

IETF (Internet Engineering Task Force), 95

IGP (interior gateway protocols), 121, 128

IMAP (Internet Message Access Protocol), 20

inside global addresses, 238

inside local addresses, 238


interface fastethernet command, 53

interface g0/1.10 command, 198

interface IDs, 112

interface keyword, 244

interface range command, 55


interface vlan 123 command, 53

interface vlan command, 200,-202

interfaces

assigning VLANs to, 73-75

shutting down, 264


common problems on “up” inter-faces, 290

duplex and speed mismatches, 289-290

interface status codes, 288

interior gateway protocols (IGP), 121, 128

Internet Control Message Protocol (ICMP), 20

Internet Engineering Task Force (IETF), 95

Internet layer (TCP/IP), 19, 27

Internet Message Access Protocol (IMAP), 20

Internet Protocol (IP), 20

internetworks, 7

inter-VLAN routing, 269-270

legacy inter-VLAN routing, 195

multilayer switches, 197, 200-203


upstream routing, 203

IOS security

banners, 253-255

passwords, 251-253

IP (Internet Protocol), 20

ip access-group command, 228, 232-233

ip access-list extended command, 233

ip access-list standard command, 232

ip address command, 53, 147

ip address dhcp command, 211

IP addresses

DHCPv4, 205-206

DHCPv6, 212-214

duplicate addresses, troubleshooting, 268

inter-VLAN routing and IP addressing, troubleshooting, 269-270

IPv4 address conflicts, 268-269

static IP addresses, testing connectivity with, 269

ip default-gateway command, 54

ip dhcp excluded-address command, 206

ip dhcp pool command, 206

IPv6 addressing 319

ip domain-name command, 57

ip forward-protocol udp command, 211

ip helper-address address command, 210

ip http authentication enable command, 54

ip http server command, 54

ip ospf cost command, 180

ip route command, 154

ip routing command, 203

IP telephony traffic, 64

ipconfig command, 58-59

ipconfig/all command, 209

ipconfig/release command, 210

ipconfig/renew command, 210

IPv4 addressing, 79

classes of addresses, 80-81

compared to IPv6, 96

configuration requirements, 297

conflicts, 268-269

default route configuration, 158-161

header format, 79-80


private and public IP addressing, 82-83

router configuration, 133-135


command syntax, 134











static route configuration, 154-156

exit-interface parameter, 157-158

next-hop parameter, 156-157

subnet masks, 81-82

subnetting steps, 85

determining how many bits to bor-row, 86

determining new subnet mask, 87

determining subnet multiplier, 87

example 1, 88

example 2, 88

example 3, 89

listing subnets, host ranges, and broadcast addresses, 87

summarizing subnet addresses, 91-93

VLSM (variable-length subnet masking), 89-91

summary static route configuration, 161-162

IPv4-mapped IPv6 addresses, 103-104

ipv6 address autoconfig command, 217

ipv6 address dhcp command, 217

IPv6 addressing

anycast addresses, 106

compared to IPv4, 96

EUI-64 configuration, 112

default route configuration, 165

explained, 95-96

global unicast addresses, 98-101

IPv4-mapped IPv6 addresses, 103-104

link-local addresses, 101

loopback addresses, 102

migrating to, 114

multicast addresses


solicited-node multicast addresses, 104-105

320 IPv6 addressing

NAT for IPv6

private address space, 247

purpose of, 247-248


prefixes, 110-111

router configuration

EUI-64 method, 146





stateless address autoconfiguration, 113

static route configuration, 162-164

subnetting

interface ID, 112

subnet ID, 111-112

summary static route configuration, 166-167

unicast addresses, 98

unique local addresses (ULAs), 102-103

unspecified addresses, 102

writing conventions, 109-111

IPv6 Fundamentals (Graziani), 95

ipv6 nd managed-config-flag command, 214

ipv6 nd other-config-flag command, 214

ipv6 ospf area command, 186

ipv6 route command, 164

ipv6 router ospf command, 188

ipv6 unicast-routing command, 113, 145-146, 186, 216

isl keyword, 198

ISPs, configuration for CCENT skills review, 297

J-K-L

keyboard shortcuts, 47-48

LAN device connection guidelines, 6

LANs (local area networks)

device connection guidelines, 6

explained, 7

Layer 1 issues, troubleshooting

CDP, 291-292

interface status and switch configura-tion, 288

CDP, 291-292




media issues, 287

Layer 2 switching, 44

Layer 3 switching, 44

lease command, 207

legacy Ethernet technologies, 32-34

legacy inter-VLAN routing, 195

line console command, 54

line vty command, 54

link header, 29

link-local addresses, 101

link-state acknowledgment (LSAck) packets, 170

link-state advertisements (LSA), 170-172

link-state database (LSDB), building, 129

link-state request (LSR) packets, 170

link-state routing process (OSPFv2), 174-175

native VLANs 321

link-state routing protocols, 122

convergence, 131

Dijkstra Shortest Path First (SPF) algo-rithm, 130-131

link-state database (LSDb), building, 129

link-state update (LSU) packets, 170-172

link trailer, 29

local area networks (LANs)

device connection guidelines, 6

explained, 7

logical topologies, 8-9

Login banner, 253

login command, 54, 251

login local command, 253

login local vty command, 57

loopback addresses, 102

LSA (link-state advertisements), 170-172

LSAck (link-state acknowledgment) packets, 170

LSDb (link-state database), building, 129

LSR (link-state request) packets, 170

LSU (link-state update) packets, 170-172

M

management VLANs

configuring, 263

explained, 65

matching logic (ACLs), 222-223

mdix auto command, 54

media, 4-6

media issues, troubleshooting, 287

memory buffering, 44

message format (OSPFv2), 169

Message of the Day (MOTD), 253

metrics


OSPFv2, 178-180

migrating to IPv6, 114

mitigating network attacks, 250

Moran, Matthew, 309

MOTD (Message of the Day), 253

multicast addresses, 37



multicast traffic, 64

multilayer switches, 197, 200-203

N

named ACLs (access control lists), 224, 231-233

NAT (Network Address Translation), 237-238

benefits, 241

dynamic NAT, 240, 243-244

example, 239

limitations, 241

NAT for IPv6

overloading, 240-241, 244

private address space, 247

purpose of, 247-248

static NAT, 240-242

terminology, 239

topology, 238


verifying, 245

native keyword, 198

native VLANs

configuring, 263

explained, 65

322 NDP (Neighbor Discovery Protocol)

NDP (Neighbor Discovery Protocol), 104, 213

Neighbor Discovery Protocol (NDP), 104, 213

neighbor establishment (OSPFv2), 170-172

Neighbor Solicitation (NS) message, 212

netbios-name-server command, 207

network access layer (TCP/IP), 19, 27-28

Network Address Translation. See NAT

network applications



growth of, 13



Video over IP, 15




user interactions, 12

network command, 176, 186, 207

network connectivity, verifying, 58-61, 148-151

network documentation, 11-12

Network layer (OSI), 19

network management traffic, 64

network media, 4-6

network security


best practices, 250



Network Time Protocol (NTP), 256-257

networking icons, 8

networking models

OSI model


explained, 17-18

layers, 18-19

PDUs (protocol data units), 20-21

TCP/IP model

application layer, 19-21

connection establishment and ter-mination, 25

data encapsulation summary, 29


explained, 17-18

flow control, 25

Internet layer, 19, 27

layer functions, 19

network access layer, 19, 27-28

port numbers, 23-24

protocols, 19-20

transport layer, 19, 22-23

User Datagram Protocol (UDP), 26

next-hop parameter (IPv4 static rout-ing), 156-157

no passive-interface command, 178

no service dhcp command, 208

no shutdown command, 53, 198, 200, 202, 264

normal data traffic, 64

NS (Neighbor Solicitation) message, 212

NTP (Network Time Protocol), 256-257

ntp server command, 257

numbered ACLs (access control lists), 224

numbers of ports, 23-24

ports 323

O

Open Shortest Path First. See OSPFv2; OSPFv3

operational states (trunks), 278-279

organizationally unique identifier (OUI), 36

OSI model


explained, 17-18

layers, 18-19


physical layer, 38-39

OSPFv2, 128, 169

algorithm, 173

configuration, 175-180

designated routers, 173

link-state advertisements, 172

link-state routing process, 174-175

message format, 169

metric modifications, 178-180

neighbor establishment, 170-172

OSPFv3 versus

differences, 186

similarities, 185

packet types, 170

verification, 180-184

OSPFv3

configuration, 186-187

OSPFv2 versus

differences, 186

similarities, 185

router ID, 188-189

verification, 189-192

OUI (organizationally unique identifier), 36

outside global addresses, 238

outside local addresses, 238

overload keyword, 244

overloading NAT (Network Address Translation), 240-241, 244

P

packet forwarding

explained, 117

path determination and switching func-tion example, 118-119

packet types (OSPFv2), 170

passive-interface command, 177-178, 188

passive-interface default command, 178

password cisco command, 54

passwords, 251-253

PAT (Port Address Translation), 240-241, 244


peer-to-peer interaction, 12

permit statement, 231

physical layer, 4, 38-39

LAN device connection guidelines, 6

network media, 4-6

Physical layer (OSI), 19

physical network security, 249

physical topologies, 8-9

ping command, 58-60, 148-149, 269

POP (Post Office Protocol), 13, 20

Port Address Translation (PAT), 240-241, 244

port-based memory, 44

ports

AUX ports, 3

console ports, 3

port assignments for CCENT skills review, 296

port-based memory, 44

324 ports

port numbers, 23-24

port speed, 55

restoring after security violations, 261-262

security, 259-261

verifying configuration, 269

positive acknowledgment, 24

post-exam information

adding certificates to resumes, 309-310



failing exams, 310


Post Office Protocol (POP), 13, 20

prefixes (IPv6), 110-111

Presentation layer (OSI), 18

private IP addressing, 82-83

Privileged EXEC mode, 46

processing ACLs (access control lists), 221-222

protocol data units (PDUs), 20-21

protocols. See specific protocols

public IP addressing, 82-83

Q

QoS (quality of service), 14

quad-zero route, 158


R

RA (Router Advertisement) message, 212

range command, 73



reference bandwidth, 178


reliability, 24-25

remark keyword, 228, 233

restoring ports after security viola-tions, 261-262

resumes, adding certificates to, 309-310

RIP (Routing Information Protocol), 126, 128, 169

route poisoning, 129

Router Advertisement (RA) message, 212

router ID

in OSPFv2, 177

in OSPFv3, 188-189

router-id command, 177, 188


router ospf command, 176

Router Solicitation (RS) message, 212

routers, 3. See also routing

IPv4 router configuration, 133-135


command syntax, 134











show cpd commands 325

IPv6 router configuration

EUI-64 method, 146





routing. See also routers

classful routing protocols, 122

classless routing protocols, 122-123

distance vector routing protocols, 121-122

dynamic routing protocols

AD (administrative distance), 126-127


routing loop prevention, 128-129

dynamic versus static routing, 119-120

EGP (exterior gateway protocols), 121

IGP (interior gateway protocols), 121, 128

link-state routing protocols, 122, 129

convergence, 131

Dijkstra Shortest Path First (SPF) algorithm, 130-131

link-state database (LSDb), build-ing, 129

methods, 119-120

packet forwarding

explained, 117

path determination and switching function example, 118-119

Routing Information Protocol (RIP), 126, 169

RS (Router Solicitation) message, 212

Running-config file, 50

S

scavenger class, 64

score reports (exams), 307

sdm prefer lanbase-routing command, 202

Secure Shell. See SSH

security

network security


best practices, 250



port security

configuring, 259-261

restoring after security violations, 261-262

Server Message Block (SMB), 13

servers

DHCPv4 server configuration, 206-210

stateful DHCPv6 server configuration, 217-218

stateless DHCPv6 server configuration, 216-217

service password-encryption com-mand, 54, 135, 252

services, disabling


HTTP, 255

small services, 256

Session layer (OSI), 18

shared memory, 44

shortcuts, 47-48

Shortest Path First (SPF) algorithm, 130-131, 173

show access-lists command, 234

show cdp interface command, 292

show commands, 48

show cpd commands, 291-292

326 show history command

show history command, 48

show interface command, 138-142, 287, 289

show interface status command, 274, 287, 289

show interfaces command, 274

show interfaces switchport command, 274, 279

show interfaces trunk command, 277-278

show ip dhcp conflict command, 269

show ip interface brief command, 137, 180, 199

show ip interface command, 234

show ip nat statistics command, 245

show ip nat translations command, 245-246

show ip ospf command, 177, 182, 189

show ip ospf database command, 189

show ip ospf interface brief command, 183, 189

show ip ospf interface command, 189

show ip ospf interfaces command, 177

show ip ospf neighbor command, 181, 189

show ip protocols command, 126, 177, 180, 189

show ip route command, 125, 136-137, 180, 199

show ip route ospf command, 189

show ip ssh command, 57

show ipv6 interface command, 147-148, 217

show ipv6 ospf command, 189

show ipv6 ospf database command, 189

show ipv6 ospf interface brief com-mand, 189

show ipv6 ospf interface command, 189

show ipv6 ospf neighbor command, 189

show ipv6 protocols command, 189

show ipv6 route command, 164

show ipv6 route ospf command, 189

show mac address-table command, 274

show ntp status command, 257

show port-security command, 260

show running-config command, 136, 235, 270

show vlan brief command, 72-74, 274

show vlan command, 274

show vlan id command, 274

show vlans command, 199

shutdown command, 202, 264

shutting down unused interfaces, 264

Simple Mail Transfer Protocol (SMTP), 13, 20

Simple Network Management Protocol (SNMP), 20

skills review and practice, 295

addressing table, 296

answer scripts, 302-305

B1 and B2 configuration requirements, 298-299



IPv4 addressing configuration require-ments, 297

ISP configuration, 297

skills challenge, 305

topology diagram, 295

verification, 299

VLANs and port assignments table, 296

SLAAC (Stateless Address Autoconfiguration), 113, 212-214

subnets 327

small services, disabling, 256

SMB (Server Message Block), 13

SMTP (Simple Mail Transfer Protocol), 13, 20

SNMP (Simple Network Management Protocol), 20


speed

port speed, 55

speed mismatches, 289-290

speed auto command, 53

SPF (Shortest Path First) algorithm, 130-131, 173

split horizon, 128

SSH (Secure Shell), 251-253

access, denying, 229-230

configuring, 56-57

remote access, 150-151

standard ACLs (access control lists), 224

standard numbered ACLs (access con-trol lists), configuring, 227

denying specific host, 228-229

denying specific subnet, 229

denying Telnet or SSH access to router, 229-230

permitting specific network, 228

Startup-config file, 50

stateful DHCPv6, 214, 217-218


Stateless Address Autoconfiguration (SLAAC), 113, 212-214

stateless DHCPv6, 214-217

states

stateful DHCPv6, 214, 217-218


Stateless Address Autoconfiguration (SLAAC), 113, 212-214

stateless DHCPv6, 214-217

trunking operational states, 278-279

static IP addresses, testing connectivity with, 269

static NAT (Network Address Translation), 240-242



exit-interface parameter, 157-158

next-hop parameter, 156-157


overview, 153-154

store-and-forward switching, 44

storing configuration files, 49-50

stub networks, 153


subnet IDs, 111-112

subnet masks

binary values, 82

determining, 87

purpose of, 81-82

subnet multiplier, determining, 87

subnets

denying, 229

IPv4 subnetting steps, 85

determining how many bits to bor-row, 86

determining new subnet mask, 87

determining subnet multiplier, 87

example 1, 88

example 2, 88

example 3, 89

listing subnets, host ranges, and broadcast addresses, 87



328 subnets

IPv6 subnetting

interface ID, 112

subnet ID, 111-112

subnet IDs, 111-112

subnet masks

binary values, 82

determining, 87

purpose of, 81-82

subnet multiplier, determining, 87


summary static routing



SVIs (switch virtual interfaces), creat-ing additional, 200-201

switch virtual interfaces (SVIs), creat-ing additional, 200-201

switches

access layer switches, 2

benefits of, 36

broadcast domains, 43

choosing, 2

Cisco IOS, accessing


CLI navigation and editing short-cuts, 47-48

command history, 48


help, 46



collusion domains, 43

configuring


basic switch configuration com-mands, 53-55

configuration commands, 53-55




port speed, 55

SSH (Secure Shell) access, 56-57

core layer switches, 2-3

distribution layer switches, 2

evolution to switching, 41-42

frame forwarding, 43-44

port configuration, verifying, 269

security

native and management VLANs, configuring, 263

port security, configuring, 259-261

ports, restoring after security vio-lations, 261-262

unused interfaces, shutting down, 264

subconfiguration files, storing and eras-ing, 49-50

SVIs (switch virtual interfaces), creating additional, 200-201

switching logic, 42-43

troubleshooting




switching logic, 42-43

switchport access vlan 123 command, 53

switchport access vlan command, 264, 274

switchport mode access command, 53, 259, 264

switchport mode dynamic auto com-mand, 279

switchport mode dynamic desirable command, 68

triggered updates 329

switchport mode trunk command, 68

switchport mode trunk dynamic auto command, 68

switchport nonegotiate command, 68

switchport port-security command, 259

switchport port-security mac-address command, 259

switchport port-security mac-address sticky command, 259

switchport port-security maximum command, 259

switchport port-security violation com-mand, 260

switchport trunk native vlan command, 264

symmetric switching, 44

T

TCP (Transmission Control Protocol), 20

TCP headers, 23

TCP/IP model

application layer, 19-21

data encapsulation summary, 29

explained, 17-18

Internet layer, 19, 27

layer functions, 19

network access layer, 19, 27-28

protocols, 19-20

transport layer, 19



features, 22

flow control, 25

port numbers, 23-24

TCP headers, 23


Telecommunications Industry Association (TIA), 35

Telnet, 19

denying, 229-231


terminal history command, 48

terminal history size 50 command, 48

terminal no history command, 48

terminal no history size command, 48

testing DHCPv4 operation, 269

TIA (Telecommunications Industry Association), 35

Time to Live (TTL) field, 129

timers, 251-253

Token Ring, 9

topologies, 8-9

topology diagram for CCENT skills review, 295

traceroute command, 149-150

tracert command, 60-61

traffic types, 64

Transmission Control Protocol (TCP), 20

transport input ssh command, 251

transport input ssh vty command, 57

transport layer

OSI, 19

TCP/IP, 19



features, 22

flow control, 25

port numbers, 23-24

TCP headers, 23


triggered updates, 129

330 troubleshooting

troubleshooting

ACLs, 281

denied protocols, 283-284

host connectivity issues, 282-283

Telnet, 284-286

default gateways, 267-268

DHCP, 268-269

duplicate IP addresses, 268

inter-VLAN routing and IP addressing, 269-270

Layer 1 issues

CDP, 291-292



interface status and switch con-figuration, 288

media issues, 287

methodology, 267

NAT (Network Address Translation), 246-247

trunking

operational states, 278-279

show interfaces trunk command, 277-278

VLANs, 273

disabled VLANs, 274-275

troubleshooting commands, 274

trunking

configuring, 75-78


explained, 66-67

troubleshooting

operational states, 278-279

show interfaces trunk command, 278

verifying, 75-78

TTL (Time to Live) field, 129

tunneling, 114

U

UDP (User Datagram Protocol), 20, 26

ULAs (unique local addresses), 102-103

unicast addresses, 98

unique local addresses (ULAs), 102-103

unspecified addresses, 102

unused interfaces, shutting down, 264

upstream routing, 203

User Datagram Protocol (UDP), 20, 26

User EXEC mode, 46

username password command, 57

UTP cabling, 34-35

V

variable-length subnet masking (VLSM), 89-91

verification, 299

ACLs (access control lists), 234-235

multilayer switches, 200-203

NAT (Network Address Translation), 245

network connectivity, 58-61, 148-151

OSPFv2, 180-184

OSPFv3, 189-192


switch port configuration, 269

VLAN assignments, 74-75

VLAN creation, 73

VLAN trunking, 75-78

Video over IP, 15

virtual local area networks. See VLANs

VLANs (virtual local area networks)

assigning to interfaces, 73-75

benefits of, 63-64

black hole VLANs, 65

write erase command 331

for CCENT skills review, 296

configuration and verification com-mands, 72-75

creating, 72-73

data VLANs, 65

default configuration, 72

default VLANs, 65

enabling/disabling on switch, 274-275

inter-VLAN routing. See inter-VLAN routing

management VLANs, 65, 263

native VLANs, 65, 263

reasons for using, 63

traffic types, 64


disabled VLANs, 274-275

troubleshooting commands, 274

trunking

configuring, 75-78


explained, 66-67


verifying, 75-78

verifying assignments, 74-75

verifying creation of, 73

voice VLANs, 65-66



voice VLANs, 65-66

VoIP (Voice over IP), 14-15

vulnerabilities (security), types of, 250

W-X-Y-Z

WANs (wide area networks), 7

wide area networks (WANs), 7

wildcard mask, 176

windowing, 25

wireless media, 4-5

write erase command, 50

31 days before your ccent certification exam · 2013-12-04 · odom’s cisco ccent/ccna icnd1...

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