Chapter 4 Implementing Inter-VLAN Routing 183

　　Describing Inter-VLAN Routing 184

　　Introduction to Inter-VLAN Routing 184

　　Inter-VLAN Routing Using an External Router (Router-on-a-Stick) 186

　　External Router: Advantages and Disadvantages 189

　　Inter-VLAN Routing Using Switch Virtual Interfaces 190

　　SVI: Advantages and Disadvantages 192

　　Routing with Routed Ports 192

　　Routed Port: Advantage and Disadvantages 193

　　L2 EtherChannel Versus L3 EtherChannel 194

　　Configuring Inter-VLAN Routing 194

　　Inter-VLAN Configuration with External Router 195

　　Implementation Planning 195

　　Inter-VLAN Configuration with SVI 197

　　Implementation Plan 197

　　Switch Virtual Interface Configuration 198

　　SVI Autostate 199

　　Configuring Routed Port on a Multilayer Switch 200

　　Verifying Inter-VLAN Routing 201

　　Troubleshooting Inter-VLAN Problems 204

　　Example of a Troubleshooting Plan 205

　　Configuration of Layer 3 EtherChannel 206

　　Routing Protocol Configuration 208

　　Verifying Routing Protocol 208

　　Implementing Dynamic Host Configuration Protocol in a Multilayer Switched Environment 210

　　DHCP Operation 211

　　Configuring DHCP and Verifying DHCP 212

　　Configure DHCP on the Multilayer Switch 212

　　Configure DHCP Relay 213

　　Verifying DHCP Operation 214

　　Deploying CEF-Based Multilayer Switching 215

　　Multilayer Switching Concepts 215

　　Explaining Layer 3 Switch Processing 216

　　CAM and TCAM Tables 217

　　Distributed Hardware Forwarding 220

　　Cisco Switching Methods 221

　　Route Caching 222

　　Topology-Based Switching 223

　　CEF Processing 225

　　CEF Operation and Use of TCAM 227

　　CEF Modes of Operation 227

　　Address Resolution Protocol Throttling 228

　　Sample CEF-Based MLS Operation 230

　　CEF-Based MLS Load Sharing 231

　　Configuring CEF and Verifying CEF Configuration 232

　　CEF-Based MLS Configuration 232

　　CEF-Based MLS Verification 232

　　Troubleshooting CEF 236

　　Summary 237

　　Review Questions 237

　　Chapter 5 Implementing High Availability and Redundancy in a Campus Network 243

　　Understanding High Availability 244

　　Components of High Availability 244

　　Redundancy 245

　　Technology 246

　　People 246

　　Processes 247

　　Tools 248

　　Resiliency for High Availability 249

　　Network-Level Resiliency 249

　　High Availability and Failover Times 249

　　Optimal Redundancy 251

　　Provide Alternate Paths 252

　　Avoid Too Much Redundancy 253

　　Avoid Single Point of Failure 253

　　Cisco NSF with SSO 254

　　Routing Protocols and NSF 255