Introduction
Part I Forwarding
Chapter 1 Packet Forwarding 2
“Do I Know This Already?” Quiz 2
Foundation Topics 3
Network Device Communication 3
Layer 2 Forwarding 4
Layer 3 Forwarding 19
Forwarding Architectures 26
Process Switching 26
Software CEF 29
Hardware CEF 30
SDM Templates 30
Exam Preparation Tasks 32
Use the Command Reference to Check Your Memory 33
References in This Chapter 34
Part II Layer 2
Chapter 2 Spanning Tree Protocol 36
“Do I Know This Already?” Quiz 36
Foundation Topics 38
Spanning Tree Protocol Fundamentals 38
IEEE 802.1D STP 38
Building the STP Topology 41
STP Topology Changes 49
Rapid Spanning Tree Protocol 53
RSTP (802.1W) Port States 54
RSTP (802.1W) Port Roles 54
RSTP (802.1W) Port Types 54
Building the RSTP Topology 55
RSTP Convergence 55
Exam Preparation Tasks 56
Use the Command Reference to Check Your Memory 56
Chapter 3 Advanced STP Tuning 58
“Do I Know This Already?” Quiz 58
Foundation Topics 59
STP Topology Tuning 59
Placing the Root Bridge 60
Modifying STP Root Port and Blocked Switch Port Locations 63
Modifying STP Port Priority 66
Additional STP Protection Mechanisms 67
Root Guard 68
STP Portfast 68
BPDU Guard 70
BPDU Filter 72
Problems with Unidirectional Links 73
Exam Preparation Tasks 76
Use the Command Reference to Check Your Memory 77
Chapter 4 Multiple Spanning Tree Protocol 80
“Do I Know This Already?” Quiz 80
Foundation Topics 81
Multiple Spanning Tree Protocol 81
MST Instances (MSTIs) 83
MST Configuration 84
MST Verification 85
MST Tuning 87
Common MST Misconfigurations 89
MST Region Boundary 90
Exam Preparation Tasks 92
Use the Command Reference to Check Your Memory 92
Chapter 5 VLAN Trunks and EtherChannel Bundles 94
“Do I Know This Already?” Quiz 94
Foundation Topics 96
VLAN Trunking Protocol 96
VTP Communication 97
VTP Configuration 98
VTP Verification 99
Dynamic Trunking Protocol 101
EtherChannel Bundle 104
Dynamic Link Aggregation Protocols 106
Verifying EtherChannel Status 108
Viewing EtherChannel Neighbors 110
Verifying EtherChannel Packets 113
Advanced LACP Configuration Options 114
Troubleshooting EtherChannel Bundles 118
Load Balancing Traffic with EtherChannel Bundles 119
Exam Preparation Tasks 121
Use the Command Reference to Check Your Memory 121
Part III Routing
Chapter 6 IP Routing Essentials 124
“Do I Know This Already?” Quiz 124
Foundation Topics 126
Routing Protocol Overview 126
Distance Vector Algorithms 128
Enhanced Distance Vector Algorithms 129
Link-State Algorithms 130
Path Vector Algorithm 131
Path Selection 132
Prefix Length 133
Administrative Distance 133
Metrics 135
Static Routing 137
Static Route Types 138
Floating Static Routing 141
Static Routes to Null Interfaces 143
IPv6 Static Routes 145
Policy-based Routing 146
Virtual Routing and Forwarding 149
Exam Preparation Tasks 151
Use the Command Reference to Check Your Memory 153
Chapter 7 EIGRP 154
“Do I Know This Already?” Quiz 154
Foundation Topics 156
EIGRP Fundamentals 156
Autonomous Systems 157
EIGRP Terminology 157
Topology Table 159
EIGRP Neighbors 160
Path Metric Calculation 160
Wide Metrics 162
Metric Backward Compatibility 163
Load Balancing 163
Failure Detection and Timers 164
Convergence 164
Route Summarization 166
Exam Preparation Tasks 167
References in This Chapter 168
Chapter 8 OSPF 170
“Do I Know This Already?” Quiz 170
Foundation Topics 172
OSPF Fundamentals 172
Inter-Router Communication 174
OSPF Hello Packets 175
Router ID 175
Neighbors 175
Designated Router and Backup Designated Router 176
OSPF Configuration 178
OSPF Network Statement 178
Interface-Specific Configuration 180
Statically Setting the Router ID 180
Passive Interfaces 181
Requirements for Neighbor Adjacency 181
Sample Topology and Configuration 181
Confirmation of Interfaces 184
Verification of OSPF Neighbor Adjacencies 185
Verification of OSPF Routes 186
Default Route Advertisement 187
Common OSPF Optimizations 188
Link Costs 189
Failure Detection 189
DR Placement 190
OSPF Network Types 194
Exam Preparation Tasks 198
Use the Command Reference to Check Your Memory 199
References in This Chapter 200
Chapter 9 Advanced OSPF 202
“Do I Know This Already?” Quiz 202
Foundation Topics 204
Areas 204
Area ID 207
OSPF Route Types 207
Link-State Advertisements 209
LSA Sequences 210
LSA Age and Flooding 210
LSA Types 210
Discontiguous Networks 217
OSPF Path Selection 218
Intra-Area Routes 218
Inter-Area Routes 219
Equal-Cost Multipathing 220
Summarization of Routes 220
Summarization Fundamentals 221
Inter-Area Summarization 222
Summarization Metrics 222
Configuration of Inter-Area Summarization 223
Route Filtering 224
Filtering with Summarization 225
Area Filtering 225
Exam Preparation Tasks 228
Use the Command Reference to Check Your Memory 229
References in This Chapter 229
Chapter 10 OSPFv3 230
“Do I Know This Already?” Quiz 230
Foundation Topics 231
OSPFv3 Fundamentals 231
OSPFv3 Link-State Advertisement 232
OSPFv3 Communication 232
OSPFv3 Configuration 233
OSPFv3 Verification 235
Passive Interface 237
Summarization 238
Network Type 239
IPv4 Support in OSPFv3 240
Exam Preparation Tasks 242
Use the Command Reference to Check Your Memory 242
References in This Chapter 243
Chapter 11 BGP 244
“Do I Know This Already?” Quiz 244
Foundation Topics 246
BGP Fundamentals 246
Autonomous System Numbers 246
Path Attributes 247
Loop Prevention 247
Address Families 248
Inter-Router Communication 248
BGP Neighbor States 253
Basic BGP Configuration 255
Verification of BGP Sessions 257
Route Advertisement 260
Receiving and Viewing Routes 262
BGP Route Advertisements from Indirect Sources 265
IPv4 Route Summarization 268
Aggregate Address 269
Atomic Aggregate 274
Route Aggregation with AS_SET 276
Multiprotocol BGP for IPv6 278
IPv6 Configuration 279
IPv6 Route Summarization 284
Exam Preparation Tasks 285
Use the Command Reference to Check Your Memory 286
References in This Chapter 287
Chapter 12 Advanced BGP 288
“Do I Know This Already?” Quiz 288
Foundation Topics 290
BGP Multihoming 291
Resiliency in Service Providers 291
Internet Transit Routing 292
Branch Transit Routing 293
Conditional Matching 295
Access Control Lists 295
Prefix Matching 297
Regular Expressions (regex) 300
Route Maps 301
Conditional Matching 302
Optional Actions 304
The continue Keyword 305
BGP Route Filtering and Manipulation 306
Distribute List Filtering 307
Prefix List Filtering 308
AS_Path ACL Filtering 309
Route Maps 311
Clearing BGP Connections 313
BGP Communities 313
Well-Known Communities 314
Enabling BGP Community Support 314
Conditionally Matching BGP Communities 315
Setting Private BGP Communities 317
Understanding BGP Path Selection 318
Routing Path Selection Using Longest Match 319
BGP Best Path Overview 320
Exam Preparation Tasks 329
Use the Command Reference to Check Your Memory 331
References in This Chapter 332
Chapter 13 Multicast 334
“Do I Know This Already?” Quiz 334
Foundation Topics 337
Multicast Fundamentals 337
Multicast Addressing 340
Layer 2 Multicast Addresses 342
Internet Group Management Protocol 343
IGMPv2 344
IGMPv3 346
IGMP Snooping 346
Protocol Independent Multicast 349
PIM Distribution Trees 349
PIM Terminology 352
PIM Dense Mode 354
PIM Sparse Mode 357
Reverse Path Forwarding 360
PIM Forwarder 361
Rendezvous Points 363
Static RP 364
Auto-RP 364
PIM Bootstrap Router 366
Exam Preparation Tasks 367
References in This Chapter 369
Part IV Services
Chapter 14 Quality of Service (QoS) 370
“Do I Know This Already?” Quiz 371
Foundation Topics 374
The Need for QoS 374
Lack of Bandwidth 374
Latency and Jitter 374
Packet Loss 376
QoS Models 377
Modular QoS CLI 379
Classification and Marking 381
Classification 381
MQC Classification Configuration 382
Marking 385
DSCP Per-Hop Behaviors 387
Scavenger Class 391
Trust Boundary 391
Class-Based Marking Configuration 392
A Practical Example: Wireless QoS 393
Policing and Shaping 394
Placing Policers and Shapers in the Network 395
Markdown 395
Token Bucket Algorithms 395
Class-Based Policing Configuration 398
Types of Policers 399
Congestion Management and Avoidance 406
Congestion Management 406
Congestion-Avoidance Tools 408
CBWFQ Configuration 410
Exam Preparation Tasks 414
Use the Command Reference to Check Your Memory 416
References in This Chapter 417
Chapter 15 IP Services 418
“Do I Know This Already?” Quiz 418
Foundation Topics 420
Time Synchronization 420
Network Time Protocol 420
NTP Configuration 421
Stratum Preference 424
NTP Peers 424
Precision Time Protocol (PTP) 425
PTP Configuration 427
First-Hop Redundancy Protocol 429
Object Tracking 430
Hot Standby Router Protocol 432
Virtual Router Redundancy Protocol 438
Gateway Load Balancing Protocol 441
Network Address Translation 446
NAT Topology 447
Static NAT 449
Pooled NAT 455
Port Address Translation 458
Exam Preparation Tasks 461
Use the Command Reference to Check Your Memory 462
Part V Overlay
Chapter 16 Overlay Tunnels 466
“Do I Know This Already?” Quiz 467
Foundation Topics 469
Generic Routing Encapsulation (GRE) Tunnels 469
GRE Tunnel Configuration 470
GRE Configuration Example 472
Problems with Overlay Networks: Recursive Routing 474
IPsec Fundamentals 475
Authentication Header 476
Encapsulating Security Payload 477
Transform Sets 478
Internet Key Exchange 480
IKEv1 480
IPsec VPNs 484
Site-to-Site IPsec Configuration 486
Cisco Locator/ID Separation Protocol (LISP) 495
LISP Architecture and Protocols 497
LISP Operation 499
Virtual Extensible Local Area Network (VXLAN) 504
Exam Preparation Tasks 507
Use the Command Reference to Check Your Memory 509
Part VI Wireless
Chapter 17 Wireless Signals and Modulation 510
“Do I Know This Already?” Quiz 510
Foundation Topics 512
Understanding Basic Wireless Theory 512
Understanding Frequency 514
Understanding Phase 519
Measuring Wavelength 519
Understanding RF Power and dB 520
Carrying Data Over an RF Signal 531
Maintaining AP–Client Compatibility 533
Using Multiple Radios to Scale Performance 535
Maximizing the AP–Client Throughput 538
Exam Preparation Tasks 540
Chapter 18 Wireless Infrastructure 542
“Do I Know This Already?” Quiz 542
Foundation Topics 545
Wireless Deployment Models 545
Autonomous Deployment 545
Cisco AP Operation 547
Cisco Wireless Deployments 548
Pairing Lightweight APs and WLCs 552
AP States 552
Discovering a WLC 554
Selecting a WLC 555
Maintaining WLC Availability 556
Segmenting Wireless Configurations 557
Leveraging Antennas for Wireless Coverage 559
Radiation Patterns 560
Gain 562
Beamwidth 563
Polarization 563
Omnidirectional Antennas 564
Directional Antennas 567
Exam Preparation Tasks 570
Chapter 19 Understanding Wireless Roaming and Location Services 572
“Do I Know This Already?” Quiz 572
Foundation Topics 574
Roaming Overview 574
Roaming Between Autonomous APs 574
Intracontroller Roaming 577
Intercontroller Roaming 579
Layer 2 Roaming 579
Layer 3 Roaming 581
Scaling Mobility with Mobility Groups 583
Locating Devices in a Wireless Network 584
Exam Preparation Tasks 587
Chapter 20 Authenticating Wireless Clients 590
“Do I Know This Already?” Quiz 590
Foundation Topics 592
Open Authentication 593
Authenticating with Pre-Shared Key 595
Authenticating with EAP 597
Configuring EAP-Based Authentication with External RADIUS Servers 600
Verifying EAP-Based Authentication Configuration 602
Authenticating with WebAuth 603
Exam Preparation Tasks 606
Chapter 21 Troubleshooting Wireless Connectivity 608
“Do I Know This Already?” Quiz 608
Foundation Topics 610
Troubleshooting Client Connectivity from the WLC 611
Checking the Client's Association and Signal Status 613
Checking the Client Properties 614
Checking the AP Properties 614
Checking the Client Security 615
Troubleshooting the Client 615
Troubleshooting Connectivity Problems at the AP 617
Exam Preparation Tasks 620
Part VII Architecture
Chapter 22 Enterprise Network Architecture 622
“Do I Know This Already?” Quiz 622
Foundation Topics 624
Hierarchical LAN Design Model 624
Access Layer 625
Distribution Layer 627
Core Layer 628
High Availability Network Design 629
High Availability Technologies 630
Enterprise Network Architecture Options 632
Two-Tier Design (Collapsed Core) 632
Three-Tier Design 634
Layer 2 Access Layer (STP Based) 634
Layer 3 Access Layer (Routed Access) 636
Simplified Campus Design 637
Software-Defined Access (SD-Access) Design 640
Exam Preparation Tasks 640
Chapter 23 Fabric Technologies 642
“Do I Know This Already?” Quiz 643
Foundation Topics 645
Software-Defined Access (SD-Access) 645
What Is SD-Access? 646
SD-Access Architecture 646
Physical Layer 647
Controller Layer 656
Management Layer 657
Software-Defined WAN (SD-WAN) 661
Cisco SD-WAN Architecture 661
vBond Orchestrator 662
vManage NMS 663
vSmart Controller 663
Cisco SD-WAN Edge Devices 663
vAnalytics 664
Cisco SD-WAN Cloud OnRamp 664
SD-WAN Policy 665
Application-Aware Routing 665
Cloud OnRamp for SaaS 666
Cloud OnRamp for IaaS 668
Exam Preparation Tasks 669
Chapter 24 Network Assurance 672
Do I Know This Already? 672
Foundation Topics 674
Network Diagnostic Tools 675
ping 675
traceroute 680
Debugging 685
Conditional Debugging 692
Simple Network Management Protocol (SNMP) 695
syslog 701
NetFlow and Flexible NetFlow 706
Switched Port Analyzer (SPAN) Technologies 716
Local SPAN 717
Specifying the Source Ports 717
Remote SPAN (RSPAN) 720
Encapsulated Remote SPAN (ERSPAN) 722
IP SLA 724
Cisco DNA Center Assurance 728
Exam Preparation Tasks 734
Part VIII Security
Chapter 25 Secure Network Access Control 736
“Do I Know This Already?” Quiz 736
Foundation Topics 738
Network Security Design for Threat Defense 738
Next-Generation Endpoint Security 741
Cisco Talos 741
Cisco Secure Malware Analytics (Threat Grid) 742
Cisco Advanced Malware Protection (AMP) 742
Cisco Secure Client (AnyConnect) 744
Cisco Umbrella 744
Cisco Secure Web Appliance (WSA) 746
Cisco Secure Email (ESA) 748
Cisco Secure IPS (FirePOWER NGIPS) 749
Cisco Secure Firewall (NGFW) 751
Cisco Secure Firewall Management Center (FMC) 753
Cisco Secure Network Analytics (Stealthwatch Enterprise) 753
Cisco Secure Cloud Analytics (Stealthwatch Cloud) 755
Cisco Identity Services Engine (ISE) 756
Network Access Control (NAC) 758
802.1x 758
MAC Authentication Bypass (MAB) 762
Web Authentication (WebAuth) 764
Enhanced Flexible Authentication (FlexAuth) 766
Cisco Identity-Based Networking Services (IBNS) 2.0 766
Cisco TrustSec 766
MACsec 772
Exam Preparation Tasks 774
Chapter 26 Network Device Access Control and Infrastructure Security 778
“Do I Know This Already?” Quiz 778
Foundation Topics 781
Access Control Lists (ACLs) 781
Numbered Standard ACLs 782
Numbered Extended ACLs 783
Named ACLs 784
Port ACLs (PACLs) and VLAN ACLs (VACLs) 785
PACL, VACL, and RACL Interaction 787
Terminal Lines and Password Protection 788
Password Types 789
Password Encryption 789
Username and Password Authentication 790
Configuring Line Local Password Authentication 790
Verifying Line Local Password Authentication 791
Configuring Line Local Username and Password Authentication 792
Verifying Line Local Username and Password Authentication 792
Privilege Levels and Role-Based Access Control (RBAC) 793
Verifying Privilege Levels 794
Controlling Access to vty Lines with ACLs 796
Verifying Access to vty Lines with ACLs 796
Controlling Access to vty Lines Using Transport Input 797
Verifying Access to vty Lines Using Transport Input 798
Enabling SSH vty Access 800
Auxiliary Port 802
EXEC Timeout 802
Absolute Timeout 802
Authentication, Authorization, and Accounting (AAA) 803
TACACS+ 803
RADIUS 804
Configuring AAA for Network Device Access Control 805
Verifying AAA Configuration 809
Zone-Based Firewall (ZBFW) 809
The Self Zone 810
The Default Zone 810
ZBFW Configuration 811
Verifying ZBFW 816
Control Plane Policing (CoPP) 817
Configuring ACLs for CoPP 817
Configuring Class Maps for CoPP 818
Configuring the Policy Map for CoPP 819
Applying the CoPP Policy Map 819
Verifying the CoPP Policy 820
Device Hardening 822
Exam Preparation Tasks 823
Use the Command Reference to Check Your Memory 824
Part IX SDN
Chapter 27 Virtualization 826
“Do I Know This Already?” Quiz 826
Foundation Topics 828
Server Virtualization 828
Virtual Machines 828
Containers 830
Virtual Switching 831
Network Functions Virtualization 833
NFV Infrastructure 834
Virtual Network Functions 834
Virtualized Infrastructure Manager 834
Element Managers 835
Management and Orchestration 836
Operations Support System (OSS)/Business Support System (BSS) 836
VNF Performance 836
Cisco Enterprise Network Functions Virtualization (ENFV) 842
Exam Preparation Tasks 847
Chapter 28 Foundational Network Programmability Concepts 850
“Do I Know This Already?” Quiz 850
Foundation Topics 854
Command-Line Interface 854
Application Programming Interface 855
Northbound API 855
Southbound API 856
Representational State Transfer (REST) APIs 856
API Tools and Resources 857
Introduction to Postman 857
Data Formats (XML and JSON) 860
Cisco DNA Center APIs 862
Cisco vManage APIs 867
Data Models and Supporting Protocols 870
YANG Data Models 870
Cisco DevNet 877
Documentation 878
Learn 878
Technologies 878
Community 879
Events 879
GitHub 880
Basic Python Components and Scripts 882
Exam Preparation Tasks 889
References in This Chapter 890
Chapter 29 Introduction to Automation Tools 892
“Do I Know This Already?” Quiz 892
Foundation Topics 894
Embedded Event Manager 894
EEM Applets 895
EEM and Tcl Scripts 899
EEM Summary 901
Agent-Based Automation Tools 902
Puppet 902
Chef 904
SaltStack (Agent and Server Mode) 909
Agentless Automation Tools 912
Ansible 912
Puppet Bolt 922
SaltStack SSH (Server-Only Mode) 923
Comparing Tools 924
Exam Preparation Tasks 925
Chapter 30 Final Preparation 926
Getting Ready 926
Tools for Final Preparation 927
Pearson Test Prep Practice Test Software and Questions on the Website 927
Customizing Your Exams 928
Updating Your Exams 929
Premium Edition 929
Chapter-Ending Review Tools 930
Suggested Plan for Final Review/Study 930
Summary 930
Chapter 31 ENCOR 350-401 Exam Updates 932
The Purpose of This Chapter 932
About Possible Exam Updates 932
Impact on You and Your Study Plan 933
News About the Next Exam Release 934
Updated Technical Content 934
Appendix A Answers to the “Do I Know This Already?” Questions 936
Glossary 956

Online Elements
Appendix B Memory Tables
Appendix C Memory Tables Answer Key
Appendix D Study Planner
Glossary

9780138216764 TOC 8/17/2023