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 Ciscos Way of Troubleshooting IP 134 Determining IP Address Problems 137 Summary 141 Chapter 6 Ciscos 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 T