Introduction xxv
Chapter 1 Basic Network and Routing Concepts 1
Differentiating Routing Protocols 2
Enterprise Network Infrastructure 2
Role of Dynamic Routing Protocols 3
Choosing a of Dynamic Routing Protocols 5
IGP versus EGP 5
Types of Routing Protocols 7
Convergence 8
Route Summarization 9
Route Protocol Scalability 10
Understanding Network Technologies 10
Traffic Types 11
IPv6 Address Types 13
ICMPv6 Neighbor Discovery 14
Network Types 15
NBMA Networks 16
Routing Over the Internet 18
Connecting Remote Locations with Headquarters 18
Principles of Static Routing 19
Configuring an IPv4 Static Route 20
Configuring a Static Default Route 22
Basic PPP Overview 23
PPP Authentication Overview 23
PPPoE 26
Basic Frame Relay Overview 28
VPN Connectivity Overview 31
MPLS-based VPNs 31
Tunneling VPNs 32
Hybrid VPNs 32
Routing Across MPLS VPNs 32
Routing Over GRE Tunnel 34
Dynamic Multipoint Virtual Private Network 35
Multipoint GRE 36
NHRP 37
IPsec 39
Routing and TCP/IP Operations 40
MSS, Fragmentation, and PMTUD 40
IPv4 Fragmentation and PMTUD 41
Bandwidth Delay Product 41
TCP Starvation 42
Latency 42
ICMP Redirect 42
Implementing RIPng 43
RIP Overview 43
RIPv2 Overview 45
Configuring RIPng 47
Basic RIPng Configuration 47
Propagating a Default Route 50
Investigating the RIPng Database 53
Summary 55
Review Questions 56
Chapter 2 EIGRP Implementation 59
Establishing EIGRP Neighbor Relationships 60
EIGRP Features 60
EIGRP Features 62
EIGRP Operation Overview 63
Configuring and Verifying Basic EIGRP for IPv4 64
Manipulating EIGRP Timers 73
EIGRP Neighbor Relationship over Frame Relay 74
Establishing EIGRP over Layer 3 MPLS VPN 74
Establishing EIGRP over Layer 2 MPLS VPN 75
Building the EIGRP Topology Table 76
Building and Examining the EIGRP Topology Table 77
Choosing the Best Path 80
Exchange of Routing Knowledge in EIGRP 88
EIGRP Metric 88
EIGRP Metric Calculation 89
EIGRP Wide Metrics 90
EIGRP Metric Calculation Example 90
EIGRP Metric Calculation Example 91
EIGRP Path Calculation Example 92
Optimizing EIGRP Behavior 94
EIGRP Queries 95
EIGRP Stub Routers 96
Configuring EIGRP Stub Routing 97
EIGRP Stub Options 100
Stuck in Active 108
Reducing Query Scope by Using Summary Routes 109
Configuring EIGRP Summarization 110
Determining the Summary Route 116
Obtaining Default Route 120
Load Balancing with EIGRP 123
Configuring EIGRP Load Balancing 123
EIGRP Load Balancing 124
EIGRP Load Balancing Across Unequal-Metric Paths 126
Configuring EIGRP for IPv6 128
Overview of EIGRP for IPv6 128
Configuring and Verifying EIGRP for IPv6 129
EIGRP for IPv6 Configuration 130
Determining the IPv6 Summary Route 134
Named EIGRP Configuration 136
Introduction to Named EIGRP Configuration 136
Configuring Named EIGRP 137
Address Families 139
EIGRP for IPv4 Address Family 139
EIGRP for IPv6 Address Family 142
Named EIGRP Configuration Modes 148
Classic Versus Named EIGRP Configuration 150
Summary 151
Review Questions 152
Chapter 3 OSPF Implementation 155
Establishing OSPF Neighbor Relationships 155
OSPF Features 156
OSPF Operation Overview 157
Hierarchical Structure of OSPF 158
Design Restrictions of OSPF 160
OSPF Message Types 160
Basic OSPF Configuration 161
Optimizing OSPF Adjacency Behavior 170
Using OSPF Priority in the DR/BDR Election 174
OSPF Behavior in NBMA Hub-and-Spoke Topology 175
The Importance of MTU 177
Manipulating OSPF Timers 179
OSPF Neighbor Relationship over Point-to-Point Links 182
OSPF Neighbor Relationship over Layer 3 MPLS VPN 182
OSPF Neighbor Relationship over Layer 2 MPLS VPN 184
OSPF Neighbor States 184
OSPF Network Types 186
Configuring Passive Interfaces 187
Building the Link-State Database 187
OSPF LSA Types 188
Examining the OSPF Link-State Database 189
OSPF Link-State Database 190
OSPF Type 2 Network LSA 196
OSPF Type 3 Summary LSA 197
OSPF Type 4 ASBR Summary LSA 199
OSPF Type 5 External LSA 201
Periodic OSPF Database Changes 203
Exchanging and Synchronizing LSDBs 204
Synchronizing the LSDB on Multiaccess Networks 206
Running the SPF Algorithm 207
Configuring OSPF Path Selection 208
OSPF Path Selection 208
OSPF Best Path Calculation 210
Default OSPF Costs 211
Calculating the Cost of Intra-Area Routes 214
Calculating the Cost of Interarea Routes 214
Selecting Between Intra-Area and Interarea Routes 215
Optimizing OSPF Behavior 215
OSPF Route Summarization 216
Benefits of Route Summarization 217
Configuring OSPF Route Summarization 218
Summarization on ABRs 223
Summarization on ASBRs 224
OSPF Virtual Links 225
Configuring OSPF Virtual Links 227
Configuring OSPF Stub Areas 229
OSPF Stub Areas 230
OSPF Totally Stubby Areas 234
Cost of the Default Route in a Stub Area 236
The default-information originate Command 237
Other Stubby Area Types 238
OSPFv3 239
Configuring OSPFv3 240
Implementing OSPFv3 241
OSPFv3 for IPv4 and IPv6 246
Configuring Advanced OSPFv3 260
OSPFv3 Caveats 261
Summary 262
Review Questions 263
Chapter 4 Manipulating Routing Updates 267
Using Multiple IP Routing Protocols on a Network 267
Why Run Multiple Routing Protocols? 269
Running Multiple Routing Protocols 269
Administrative Distance 269
Multiple Routing Protocols Solutions 270
Implementing Route Redistribution 270
Defining Route Redistribution 270
Planning to Redistribute Routes 271
Redistributing Routes 271
Seed Metrics 272
Default Seed Metrics 273
Configuring and Verifying Basic Redistribution in IPv4 and IPv6 275
Redistributing OSPFv2 Routes into the EIGRP Routing Domain 276
Redistributing OSPFv3 Routes into the EIGRP for IPv6 Routing Domain 279
Redistributing EIGRP Routes into the OSPFv2 Routing Domain 281
Redistributing EIGRP for IPv6 Routes into the OSPFv3 Routing Domain 285
Types of Redistribution Techniques 287
One-Point Redistribution 287
Multipoint Redistribution 288
Redistribution Problems 289
Preventing Routing Loops in a Redistribution Environment 291
Verifying Redistribution Operation 292
Controlling Routing Update Traffic 292
Why Filter Routes? 292
Route Filtering Methods 293
Using Distribute Lists 294
Configuring Distribute Lists 294
Distribute List and ACL Example 295
Using Prefix Lists 297
Prefix List Characteristics 297
Configuring Prefix Lists 298
Distribute List and Prefix List Example 299
Prefix List Examples 300
Verifying Prefix Lists 301
Manipulating Redistribution Using ACLs, Prefix Lists, and Distribute Lists 302
Using Route Maps 305
Understanding Route Maps 305
Route Map Applications 305
Configuring Route Maps 306
Route Map Match and Set Statements 308
Configuring Route Redistribution Using Route Maps 310
Using Route Maps with Redistribution 310
Manipulating Redistribution Using Route Maps 311
Mutual Redistribution without Route Filtering 312
Mutual Redistribution with Route Maps 313
Change Administrative Distance to Enable Optimal Routing 315
Manipulating Redistribution Using Route Tagging 318
Caveats of Redistribution 319
Summary 320
References 323
Review Questions 323
Chapter 5 Path Control Implementation 327
Using Cisco Express Forwarding Switching 327
Control and Data Plane 328
Cisco Switching Mechanisms 328
Process and Fast Switching 332
Cisco Express Forwarding 333
Analyzing Cisco Express Forwarding 335
Verify the Content of the CEF Tables 335
Enable and Disable CEF by Interface and Globally 341
Understanding Path Control 343
The Need for Path Control 343
Implementing Path Control Using Policy-Based Routing 344
PBR Features 344
Steps for Configuring PBR 345
Configuring PBR 346
Verifying PBR 348
Configuring PBR Example 348
Implementing Path Control Using Cisco IOS IP SLAs 354
PBR and IP SLA 354
IP SLA Features 354
Steps for Configuring IP SLAs 356
Verifying Path Control Using IOS IP SLAs 360
Configuring IP SLA Example 361
Configuring PBR and IP SLA Example 364
Summary 369
References 370
Review Questions 370
Chapter 6 Enterprise Internet Connectivity 373
Planning Enterprise Internet Connectivity 374
Connecting Enterprise Networks to an ISP 374
Enterprise Connectivity Requirements 374
ISP Redundancy 375
Public IP Address Assignment 376
The Internet Assigned Numbers Authority 376
Regional Internet Registries 377
Public IP Address Space 377
Autonomous System Numbers 378
Establishing Single-Homed IPv4 Internet Connectivity 381
Configuring a Provider-Assigned IPv4 Address 381
DHCP Operation 382
Obtaining a Provider-Assigned IPv4 Address with DHCP 383
Configuring a Router as a DHCP Server and DHCP Relay Agent 384
NAT 385
Configuring Static NAT 388
Configuring Dynamic NAT 389
Configuring PAT 390
Limitations of NAT 392
NAT Virtual Interface 393
Configuring NAT Virtual Interface 393
Verifying NAT Virtual Interface 396
Establishing Single-Homed IPv6 Internet Connectivity 398
Obtaining a Provider-Assigned IPv6 Address 398
Manual Assignment 399
Configuring Basic IPv6 Internet Connectivity 399
Stateless Address Autoconfiguration 401
DHCPv6 Operation 402
Stateless DCHPv6 403
Stateful DHCPv6 404
DHCPv6 Prefix Delegation 405
NAT for IPv6 405
NAT64 405
NPTv6 405
IPv6 ACLs 405
IPv6 ACL Characteristics 406
Configuring IPv6 ACLs 406
Securing IPv6 Internet Connectivity 409
Improving Internet Connectivity Resilience 410
Drawbacks of a Single-Homed Internet Connectivity 410
Dual-Homed Internet Connectivity 410
Dual-Homed Connectivity Options 411
Configuring Best Path for Dual-Homed Internet Connectivity 411
Multihomed Internet Connectivity 413
Summary 415
References 417
Review Questions 418
Chapter 7 BGP Implementation 423
BGP Terminology, Concepts, and Operation 424
BGP Use Between Autonomous Systems 424
Comparison with Other Scalable Routing Protocols 425
BGP Path Vector Characteristics 426
BGP Characteristics 428
BGP Tables 430
BGP Message Types 431
Open and Keepalive Messages 431
Update Messages 433
Notification Messages 433
When to Use BGP 433
When Not to Use BGP 434
Implementing Basic BGP 435
BGP Neighbor Relationships 435
External BGP Neighbors 436
Internal BGP Neighbors 437
iBGP on All Routers in a Transit Path 438
Basic BGP Configuration Requirements 442
Entering BGP Configuration Mode 442
Defining BGP Neighbors and Activating BGP Sessions 443
Basic BGP Configuration and Verification 444
Configuring and Verifying an eBGP Session 445
Configuring and Verifying an iBGP Session 449
Advertising Networks in BGP and Verifying That They Are Propagated 450
Using the Next-Hop-Self Feature 457
Understanding and Troubleshooting BGP Neighbor States 458
BGP Session Resilience 460
Sourcing BGP from Loopback Address 461
eBGP Multihop 463
Resetting BGP Sessions 464
BGP Attributes and the Path-Selection Process 467
