Introduction xxxvi Your Study Plan 2 Part I Networking Fundamentals 13 Chapter 1 Introduction to TCP/IP Networking 14 Foundation Topics 15 Perspectives on Networking 15 TCP/IP Networking Model 16 History Leading to TCP/IP 17 Overview of the TCP/IP Networking Model 18 TCP/IP Application Layer 19 TCP/IP Transport Layer 20 TCP/IP Network Layer 22 TCP/IP Link Layer (Data Link Plus Physical) 25 TCP/IP Model and Terminology 26 OSI Networking Model 28 Comparing OSI and TCP/IP 29 Describing Protocols by Referencing the OSI Layers 29 OSI Layers and Their Functions 30 OSI Layering Concepts and Benefits 31 OSI Encapsulation Terminology 31 Chapter Summary 33 Chapter 2 Fundamentals of Ethernet LANs 38 Foundation Topics 39 An Overview of LANs 39 Typical SOHO LANs 39 Typical Enterprise LANs 40 The Variety of Ethernet Physical Layer Standards 41 Consistent Behavior over All Links Using the Ethernet Data Link Layer 41 Building Physical Ethernet Networks with UTP 42 Transmitting Data Using Twisted Pairs 42 Breaking Down a UTP Ethernet Link 43 UTP Cabling Pinouts for 10BASE-T and 100BASE-T 45 UTP Cabling Pinouts for 1000BASE-T 48 Sending Data in Ethernet Networks 48 Ethernet Data-Link Protocols 49 Sending Ethernet Frames with Switches and Hubs 52 Chapter Summary 55 Chapter 3 Fundamentals of WANs 60 Foundation Topics 61 Leased-Line WANs 61 Positioning Leased Lines with LANs and Routers 61 Physical Details of Leased Lines 62 Data-Link Details of Leased Lines 64 Ethernet as a WAN Technology 67 Ethernet WANs that Create a Layer 2 Service 68 How Routers Route IP Packets Using Ethernet Emulation 68 Accessing the Internet 69 The Internet as a Large WAN 69 Internet Access (WAN) Links 71 Digital Subscriber Line 72 Cable Internet 73 Chapter Summary 75 Chapter 4 Fundamentals of IPv4 Addressing and Routing 78 Foundation Topics 79 Overview of Network Layer Functions 79 Network Layer Routing (Forwarding) Logic 79 How Network Layer Routing Uses LANs and WANs 81 IP Addressing and How Addressing Helps IP Routing 82 Routing Protocols 83 IPv4 Addressing 84 Rules for IP Addresses 84 Rules for Grouping IP Addresses 84 IP Subnetting 89 IPv4 Routing 90 IPv4 Host Routing 90 Router Forwarding Decisions and the IP Routing Table 91 IPv4 Routing Protocols 93 Other Network Layer Features 94 Using Names and the Domain Name System 95 The Address Resolution Protocol 96 ICMP Echo and the ping Command 97 Chapter Summary 98 Chapter 5 Fundamentals of TCP/IP Transport and Applications 102 Foundation Topics 103 TCP/IP Layer 4 Protocols: TCP and UDP 103 Transmission Control Protocol 103 User Datagram Protocol 111 TCP/IP Applications 112 Uniform Resource Identifiers 112 Finding the Web Server Using DNS 113 Transferring Files with HTTP 114 How the Receiving Host Identifies the Correct Receiving Application 115 Chapter Summary 117 Part I Review 120 Part II Implementing Basic Ethernet LANs 123 Chapter 6 Using the Command-Line Interface 124 Foundation Topics 125 Accessing the Cisco Catalyst Switch CLI 125 Cisco Catalyst Switches 125 Accessing the Cisco IOS CLI 126 CLI Help Features 132 The debug and show Commands 134 Configuring Cisco IOS Software 134 Configuration Submodes and Contexts 135 Storing Switch Configuration Files 137 Copying and Erasing Configuration Files 139 Chapter Summary 140 Chapter 7 Analyzing Ethernet LAN Switching 146 Foundation Topics 147 LAN Switching Concepts 147 Overview of Switching Logic 147 Forwarding Known Unicast Frames 148 Learning MAC Addresses 151 Flooding Unknown Unicast and Broadcast Frames 151 Avoiding Loops Using Spanning Tree Protocol 152 LAN Switching Summary 153 Verifying and Analyzing Ethernet Switching 154 Demonstrating MAC Learning 154 Switch Interfaces 155 Finding Entries in the MAC Address Table 157 Managing the MAC Address Table (Aging, Clearing) 158 MAC Address Tables with Multiple Switches 159 Chapter Summary 161 Chapter 8 Configuring Basic Switch Management 166 Foundation Topics 167 Securing the Switch CLI 167 Securing User Mode and Privileged Mode with Simple Passwords 167 Securing User Mode Access with Local Usernames and Passwords 171 Securing User Mode Access with External Authentication Servers 173 Securing Remote Access with Secure Shell 174 Enabling IPv4 for Remote Access 177 Host and Switch IP Settings 177 Configuring IPv4 on a Switch 179 Configuring a Switch to Learn Its IP Address with DHCP 180 Verifying IPv4 on a Switch 180 Miscellaneous Settings Useful in Lab 181 History Buffer Commands 181 The logging synchronous, exec-timeout, and no ip domain-lookup Commands 182 Chapter Summary 183 Chapter 9 Configuring Switch Interfaces 188 Foundation Topics 189 Configuring Switch Interfaces 189 Configuring Speed, Duplex, and Description 189 Configuring Multiple Interfaces with the interface range Command 191 Administratively Controlling Interface State with shutdown 191 Removing Configuration with the no Command 193 Autonegotiation 194 Port Security 197 Configuring Port Security 198 Verifying Port Security 200 Port Security Violation Actions 201 Port Security MAC Addresses as Static and Secure but Not Dynamic 202 Chapter Summary 203 Part II Review 210 Part III Ethernet LANs: Design, VLANs, and Troubleshooting 215 Chapter 10 Analyzing Ethernet LAN Designs 216 Foundation Topics 217 Analyzing Collision Domains and Broadcast Domains 217 Ethernet Collision Domains 217 Ethernet Broadcast Domains 220 Analyzing Campus LAN Topologies 223 Two-Tier Campus Design (Collapsed Core) 223 Three-Tier Campus Design (Core) 226 Topology Design Terminology 227 Analyzing LAN Physical Standard Choices 228 Ethernet Standards 229 Choosing the Right Ethernet Standard for Each Link 229 Wireless LANs Combined with Wired Ethernet 231 Chapter Summary 235 Chapter 11 Implementing Ethernet Virtual LANs 240 Foundation Topics 241 Virtual LAN Concepts 241 Creating Multiswitch VLANs Using Trunking 242 Forwarding Data Between VLANs 245 VLAN and VLAN Trunking Configuration and Verification 248 Creating VLANs and Assigning Access VLANs to an Interface 248 VLAN Trunking Protocol 252 VLAN Trunking Configuration 253 Implementing Interfaces Connected to Phones 257 Chapter Summary 262 Chapter 12 Troubleshooting Ethernet LANs 268 Foundation Topics 270 Perspectives on Applying Troubleshooting Methodologies 270 Troubleshooting on the Exams 270 A Deeper Look at Problem Isolation 271 Troubleshooting as Covered in This Book 273 Analyzing Switch Interface Status and Statistics 273 Interface Status Codes and Reasons for Nonworking States 274 Interface Speed and Duplex Issues 275 Common Layer 1 Problems on Working Interfaces 277 Predicting Where Switches Will Forward Frames 279 Predicting the Contents of the MAC Address Table 279 Analyzing the Forwarding Path 281 Analyzing Port Security Operations on an Interface 282 Troubleshooting Shutdown Mode and Err-disabled Recovery 283 Troubleshooting Restrict and Protect Modes 284 Analyzing VLANs and VLAN Trunks 286 Ensuring That the Right Access Interfaces Are in the Right VLANs 287 Access VLANs Not Being Defined 287 Access VLANs Being Disabled 288 Mismatched Trunking Operational States 288 Chapter Summary 290 Part III Review 296 Part IV IP Version 4 Addressing and Subnetting 299 Chapter 13 Perspectives on IPv4 Subnetting 300 Foundation Topics 301 Introduction to Subnetting 301 Subnetting Defined Through a Simple Example 301 Operational View Versus Design View of Subnetting 302 Analyze Subnetting and Addressing Needs 303 Rules About Which Hosts Are in Which Subnet 303 Determining the Number of Subnets 304 Determining the Number of Hosts per Subnet 305 One Size Subnet Fits All-Or Not 306 Make Design Choices 308 Choose a Classful Network 309 Choose the Mask 311 Build a List of All Subnets 315 Plan the Implementation 316 Assigning Subnets to Different Locations 316 Choose Static and Dynamic Ranges per Subnet 318 Chapter Summary 319 Chapter 14 Analyzing Classful IPv4 Networks 322 Foundation Topics 323 Classful Network Concepts 323 IPv4 Network Classes and Related Facts 323 Number of Hosts per Network 326 Deriving the Network ID and Related Numbers 326 Unusual Network IDs and Network Broadcast Addresses 328 Practice with Classful Networks 329 Practice Deriving Key Facts Based on an IP Address 329 Practice Remembering the Details of Address Classes 329 Chapter Summary 331 Chapter.