Understanding Cisco Networking Technologies, Volume 1

TODD LAMMLE, Cisco certified in almost every category, is the authority on Cisco networking and certification. His three decades of real-world experience is prevalent in his writing. He is an experienced networking engineer with very practical experience working on the largest bounded and unbounded networks in the world at such companies as Xerox, Hughes Aircraft, Texaco, AAA, Cisco, and Toshiba, among many others. Todd has published over 60 books, including the very popular and bestselling CCNA Cisco Certified Network Associate Study Guide and Cisco Firepower NGIPS. Todd runs an international training company from Texas, and a large-scale consulting business out of Colorado. You can reach Todd through his web site at www.lammle.com/ccna.

Introduction xvii

Chapter 1 Internetworking 1

Internetworking Basics 2

Internetworking Models 10

The Layered Approach 11

Advantages of Reference Models 12

The OSI Reference Model 12

The Application Layer 14

The Presentation Layer 15

The Session Layer 16

The Transport Layer 16

The Network Layer 21

The Data Link Layer 23

The Physical Layer 26

Summary 29

Chapter 2 Ethernet Networking and Data Encapsulation 31

Ethernet Networks in Review 32

Collision Domain 32

Broadcast Domain 34

CSMA/CD 35

Half- and Full-Duplex Ethernet 36

Ethernet at the Data Link Layer 38

Ethernet at the Physical Layer 45

Ethernet Cabling 48

Straight-Through Cable 49

Crossover Cable 49

Rolled Cable 51

Fiber Optic 53

Data Encapsulation 55

The Cisco Three-Layer Hierarchical Model 59

The Core Layer 60

The Distribution Layer 60

The Access Layer 61

Summary 61

Chapter 3 Introduction to TCP/IP 63

Introducing TCP/IP 64

A Brief History of TCP/IP 64

TCP/IP and the DoD Model 65

The Process/Application Layer Protocols 66

The Host-to-Host or Transport Layer Protocols 76

The Internet Layer Protocols 85

IP Addressing 93

IP Terminology 94

The Hierarchical IP Addressing Scheme 94

Private IP Addresses (RFC 1918) 99

IPv4 Address Types 101

Layer 2 Broadcasts 101

Layer 3 Broadcasts 102

Unicast Address 102

Multicast Address 103

Summary 104

Chapter 4 Easy Subnetting 105

Subnetting Basics 106

How to Create Subnets 107

Subnet Masks 108

Classless Inter-Domain Routing (CIDR) 109

IP Subnet-Zero 111

Subnetting Class C Addresses 112

Subnetting Class B Addresses 123

Summary 131

Chapter 5 Troubleshooting IP Addressing 133

Cisco’s Way of Troubleshooting IP 134

Determining IP Address Problems 137

Summary 141

Chapter 6 Cisco’s Internetworking Operating System (IOS) 143

The IOS User Interface 144

Cisco IOS 144

Connecting to a Cisco IOS Device 145

Bringing Up a Switch 147

Command-Line Interface (CLI) 147

Entering the CLI 148

Overview of Router Modes 148

CLI Prompts 149

Editing and Help Features 151

Administrative Configurations 156

Hostnames 157

Banners 157

Setting Passwords 159

Encrypting Your Passwords 165

Descriptions 166

Router and Switch Interfaces 169

Bringing Up an Interface 172

Viewing, Saving, and Erasing Configurations 177

Deleting the Configuration and Reloading the Device 179

Verifying Your Configuration 179

Summary 192

Chapter 7 Managing a Cisco Internetwork 193

The Internal Components of a Cisco Router and Switch 194

The Router and Switch Boot Sequence 195

Backing Up and Restoring the Cisco Configuration 196

Backing Up the Cisco Configuration 197

Restoring the Cisco Configuration 199

Erasing the Configuration 199

Configuring DHCP 200

DHCP Relay 202

Verifying DHCP on Cisco IOS 202

Using Telnet 203

Telnetting into Multiple Devices Simultaneously 205

Checking Telnet Connections 205

Checking Telnet Users 206

Closing Telnet Sessions 206

Resolving Hostnames 206

Building a Host Table 207

Using DNS to Resolve Names 208

Checking Network Connectivity and Troubleshooting 210

Using the ping Command 210

Using the traceroute Command 211

Debugging 212

Using the show processes Command 215

Summary 215

Chapter 8 Managing Cisco Devices 217

Managing the Configuration Register 218

Understanding the Configuration Register Bits 218

Checking the Current Configuration Register Value 220

Boot System Commands 221

Recovering Passwords 222

Backing Up and Restoring the Cisco IOS 224

Verifying Flash Memory 226

Backing Up the Cisco IOS 227

Restoring or Upgrading the Cisco Router IOS 227

Using the Cisco IOS File System (Cisco IFS) 230

Licensing 235

Right-To-Use Licenses (Evaluation Licenses) 237

Backing Up and Uninstalling the License 240

Summary 241

Chapter 9 IP Routing 243

Routing Basics 245

The IP Routing Process 247

The Cisco Router Internal Process 253

Testing Your IP Routing Understanding 254

Configuring IP Routing 258

Corp Configuration 259

SF Configuration 261

LA Configuration 265

Configuring IP Routing in Our Network 267

Static Routing 268

Default Routing 273

Dynamic Routing 276

Routing Protocol Basics 276

Routing Information Protocol (RIP) 278

Configuring RIP Routing 279

Holding Down RIP Propagations 282

Summary 284

Chapter 10 Wide Area Networks 287

Introduction to Wide Area Networks 288

WAN Topology Options 289

Defining WAN Terms 291

WAN Connection Bandwidth 292

WAN Connection Types 293

WAN Support 294

Cabling the Serial Wide Area Network 297

Serial Transmission 297

Data Terminal Equipment and Data Communication Equipment 298

High-Level Data-Link Control (HDLC) Protocol 299

Point-to-Point Protocol (PPP) 301

Link Control Protocol (LCP) Configuration Options 303

PPP Session Establishment 303

PPP Authentication Methods 304

Configuring PPP on Cisco Routers 304

Configuring PPP Authentication 305

Verifying and Troubleshooting Serial Links 305

Multilink PPP (MLP) 311

PPP Client (PPPoE) 314

Configuring a PPPoE client 315

Summary 316

Glossary 317

Index 365