目录
Table of Contents
Part I Review
1
Chapter 1
Review: The OSI Reference Model and Routing 3
Layered Network Model: OSI Reference Model 3
Peer-to-Peer Communication 4
Data Encapsulation
5
Physical Layer
6
Ethernet/802.3 Physical Connections
7
Data Link Layer
8
Ethernet/802.3 Interface
8
Network Layer
9
IP Addressing and Subnets
9
Path Determination
9
Path Communication
9
ICMP
11
ARP
11
Routing 12
Routed Versus Routing Protocols
14
IP Routing Configuration Tasks
16
Transport Layer
17
Segmenting Upper-Layer Applications 18
Establishing a Connection
18
Data Transfer
18
Reliability with Windowing
19
Acknowledgment Techniques
19
Summary
20
Key Terms
20
Check Your Understanding 23
Part II CCNA 3: Switching Basics and Intermediate Routing
27
Chapter 2
Introduction to Classless Routing 29
CIDR Overview
29
Why CIDR
29
Route Aggregation and Supemetting 30
Supemetting and Address Allocation 31
Variable-Length Subnet Masking VLSM 32
VLSM Features
32
Calculating VLSMs
34
Configuring VLSM
35
VLSM Using RIP and IGRP
36
Route Summarization
37
Summarization Within an Octet
38
Summarization with a Discontiguous Network
38
Route Flapping
39
RIP Version2
39
Short History of RIP
39
RIP Version 2 Features
40
Comparing RIPvl and RIPv2 41
Configuring RIP Version2
41
Verifying RIP V2
42
Troubleshooting RIP
44
Default Routes
45
Summary
46
Key Terms
47
Check Your Understanding 47
Chapter 3
Single-Area OSPF
49
Single-Area OSPF Concepts 49
OSPF Overview
49
OSPF Terminology
50
OSPF States
51
Comparing OSPF with Distance Vector Routing Protocols
53
Shortest Path First Algorithm
54
OSPF Network Types
54
OSPF Hello Protocol
56
Steps in OSPF Operations
56
Establishing a Router Adjacency
56
Electing a DR and BDR
57
Discovering Routes
58
Selecting the Best Route
59
Maintaining Route Information
59
Single-Area OSPF Configuration
60
Configuring a Loopback Address 61
Modifying OSPF Router Priority
61
Modifying OSPF Cost Metric 62
Configuring OSPF Authentication
63
Configuring OSPF Timers
64
Configure OSPF over NBMA 64
Full-Mesh Frame Relay
66
Partial-Mesh Frame Relay
67
Point-to-Multipoint OSPF 68
Propagating a Default Route
69
Common OSPF Configuration Issues 69
Verifying the OSPF Configuration 70
Summary
70
Key Terms
71
Check Your Understanding 71
Chapter 4
Enhanced Interior Gateway Routing Protocol 75
EIGRP Overview
75
EIGRP Processes and Technology 75
EIGRP Benefits
77
Independence from Routed Protocols
78
EIGRP Terminology
78
Neighbor Table
78
Topology Table
78
Successor
79
Feasible Successor
80
Selection of Successors and Feasible Successors 80
Stuck in Active Routes
81
Routing Table
81
Route Tagging
81
EIGRP Features and Technologies 82
Neighbor Discovery and Recovery
82
Reliable Transport Protocol
83
DUAL Finite-State Machine
83
PDMs
84
EIGRP Packet Types
84
Hello Packets
84
Acknowledgment Packets
85
Update Packets
85
Query and Reply Packets
85
EIGRP Convergence
86
Configuring EIGRP
87
Configuring EIGRP for IP
87
Configuring Bandwidth with NBMA 88
Configuring Bandwidth over a Multipoint Network
88
Configuring Bandwidth over a Hybrid Multi-point Network
89
Using the ip bandwidth-percent Command 89
Configuring EIGRP Summarization 90
Verifying Basic EIGRP 91
Summary
92
Key Terms
92
Check Your Understanding 92
Chapter 5
Switching Concepts and LAN Design 95
Ethernet/802.3 LANs
95
Ethernet/802.3 LAN Development 95
Factors That Impact Network Performance 98
Elements of Ethernet/802.3 Networks 98
Half-Duplex Ethernet Networks
99
Frill-Duplex Ethernet Networks 100
Introduction to LAN Switching 100
LAN Segmentation
101
LAN Segmentation with Bridges
102
LAN Segmentation with Routers
103
LAN Segmentation with Switches 104
The Basic Operations of a Switch 104
Ethernet Switch Latency
107
Layer 2 and Layer 3 Switching 107
Implications of Layer 2 and Layer 3
Switching
108
Symmetric and Asymmetric Switching 108
Memory Buffering
109
LAN Design
110
LAN Design Goals
110
LAN Design Considerations
110
Function and Placement of Servers 110
Segmentation Issues
111
Broadcast Domain Issues
112
LAN Design Methodology 112
Factors That Affect Network Availability 113
Designing the Physical Network Topology 113
Layer 1 Design
113
Layer 2 Design
116
Layer 3 Design
121
Basic Layer 2 Bridging and Switching 124
How Switches and Bridges Filter Frames 125
Filtering Types
125
Summary
126
Key Terms
126
Check Your Understanding
129
Chapter 6
Switches
133
Overview of Switches
133
Starting the Switch
134
Physical Startup of the Catalyst Switch 134
Switch LED Indicators
135
Verifying Port LEDs During Switch POST 136
Viewing Initial Bootup Output from the Switch 136
Examining Help in the Switch Command-Line Interface 139
LAN Switches and Hierarchical Network Design
141
The Core Layer
142
The Distribution Layer
142
Access Layer
143
Switched LANs, Access Layer Overview 143
Access Layer Switches
143
Distribution Layer Overview
144
Distribution Layer Switches
145
Core Layer Overview
145
Core Layer Switches
146
Summary
147
Key Terms
147
Check Your Understanding
148
Chapter 7
Switch Configuration
151
Microsegmentation
151
Microsegmentation Implementation
152
How a Switch Learns Addresses
153
Switch Forwarding
155
Store-and-Forward
155
Cut-Through
155
Symmetric Switching
156
Asymmetric Switching
156
Memory Buffering
156
Switches and Collision Domains
157
Switches and Broadcast Domains 158
Communication Between Switches and PCs 159
PC to Switch Transmission
159
Communication Between Switches
160
Verifying the Initial Configuration of a Catalyst Switch
160
Verifying the Catalyst Switch Default
Configuration
160
Switch Port Properties
161
VLAN Properties
162
The Flash Directory
163
Displaying IOS Version Information 163
Benefits of Using the Default Configuration 164
Configuring the Network Settings of the Catalyst Switch
164
Resetting the Switch Defaults 164
Assigning the Switch Host Name and
Passwords
165
Assigning the Switch IP Address and Default Gateway
165
Setting Port Characteristics 165
Web-Based Interface
166
Managing the MAC Address Table 167
Configuring Static MAC Addresses 168
Configuring Port Security 169
Executing Adds, Moves, and Changes 169
Managing Switch Operating System Images and Device Configuration Files
170
1900/2950 Password Recovery 170
1900/2900 Firmware IOS Upgrade 171
Summary
171
Key Terms
171
Check Your Understanding
172
Chapter 8
Spanning Tree Protocol 175
Redundant Topology Overview 175
What Is Redundancy
175
Redundant Topologies
176
Redundant Switched Topologies 176
Broadcast Storms
176
Multiple Frame Transmissions
177
MAC Database Instability 177
Spanning Tree Overview
178
Spanning-Tree Operation
178
Using Spanning Tree to Create a Loop-Free Topology
179
Advanced Functions of STP 180
Selecting the Root Bridge 181
Stages of Spanning-Tree Port States
182
Electing Designated Ports
183
Path Cost
185
STP Timers
186
Spanning-Tree Recalculation 187
Convergence
188
RSTP
188
RSTP Port States
188
Transition to Forwarding
189
Summary
189
Key Terms
190
Check Your Understanding
190
Chapter 9
Virtual LANs
193
VLAN Introduction
193
Broadcast Domains with VLANs and Routers
195
VLAN Operation
195
End-to-End VLANs
198
Geographic VLANS
198
Benefits of VLANs
198
Change Management
199
VLANs and Security
199
Using Hubs with VLANs
200
VLAN Types
201
VLAN Frame Identification 201
IEEE 802. lQ: Frame Tagging 201
Inter-Switch Link Protocol 201
FDDI 802.10
202
LANE
202
VLAN Configuration
203
Configuring Static VLANs
203
Verifying VLAN Configuration
204
Saving a VLAN Configuration 205
Deleting a VLAN Configuration
205
Troubleshooting VLANs 206
Summary
208
Key Terms
208
Check Your Understanding
208
Chapter 10
VLAN Trunking Protocol 211
Tmnking
211
Tmnking Concepts
212
Trunking Operation
212
VLANs and Trunking
213
Switch Command-Line Interfaces 214
Tmnking Implementation
214
VLAN Tmnking Protocol VTP
216
History of VTP
216
VTP Concepts
216
VTP Benefits
216
VTP Domain
217
VTP Modes
217
VTP Implementation
218
VTP Configuration
220
VTP Pruning
222
Inter-VLAN Routing
223
Inter-VLAN Issues and Solutions
224
Isolated Broadcast Domains
225
Finding the Route Between VLANs
225
Physical and Logical Interfaces 226
Dividing Physical Interfaces into Subinterfaces 226
Configuring Inter-VLAN Routing 227
Summary
227
Key Terms
228
Check Your Understanding
228
Part III CCNA 4: WAN Technologies 231
Chapter 11
Scaling IP Addresses
233
Internet Protocol Overview
233
NAT and PAT
235
NAT and PAT Features
237
Configuring NAT and PAT 238
Verifying NAT and PAT Configuration 242
Troubleshooting NAT and PAT Configuration
243
Advantages and Disadvantages of NAT 244
DHCP Overview
245
Introducing DHCP
245
BOOTP and DHCP Differences 247
DHCP Features
247
DHCP Operation
248
Configuring DHCP Operation
249
Verifying DHCP Operation
250
Troubleshooting DHCP Configuration 250
DHCP Relay
251
Summary
253
Key Terms
253
Check Your Understanding
253
Chapter 12
WAN Technologies
257
WAN Technologies Overview
257
WAN Devices
259
WAN Standards
260
WAN Encapsulation
261
WAN Link Options
262
Circuit-Switched Connections
262
Packet-Switched Connections 262
Packet and Circuit Switching
263
WAN Technologies
264
Analog Dialup
264
ISDN
265
Leased Line
266
X.25
266
Frame Relay
267
ATM
268
DSL
268
Cable Modem
269
WAN Communication
270
LAN/WAN Integration
272
Identifying and Selecting Network Capabilities
272
Identifying and Selecting a Networking Model
274
The Hierarchical Network Design Model 274
The Three-Layer Design Models
274
Three-Layer Model Components
276
Hierarchical WAN Design Advantages 278
Server Placement
279
WAN Design
281
Steps in Designing a WAN
281
Gathering Requirements
282
Analyzing Requirements
283
Sensitivity Testing
284
WAN Topology
285
How to Identify and Select Networking Capabilities
286
Other WAN Design Considerations
286
Summary
287
Key Terms
287
Check Your Understanding
288
Chapter 13
Point-to-Point Protocol 291
PPP Layered Architecture
291
Establishing a PPP Session 294
PPP Authentication Protocols
295
Password Authentication Protocol 296
CHAP
296
PPP Encapsulation and Authentication Process 296
Serial Point-to-Point Links
300
Time-Division Multiplexing 300
Demarcation Point
301
DTE and Data Communications Equipment Devices
301
HDLC Encapsulation
303
Configuring HDLC Encapsulation 304
Troubleshooting a Serial Interface 304
Configuring PPP
309
Configuring PPP Encapsulation
310
Configuring PPP Authentication 311
Verifying the Serial PPP Encapsulation Configuration
312
Troubleshooting the Serial PPP Encapsulatign Configuration
313
Summary
314
Key Terms
314
Check Your Understanding
315
Chapter 14
ISDN and DDR
319
ISDN Standards
319
ISDN Overview
320
ISDN Standards and Access Methods 322
ISDN 3-Layer Model and Protocols 324
ISDN Call Setup
325
ISDN Functions and Reference Points 327
Determining the Router ISDN Interface 328
ISDN Switch Types
329
ISDN Configuration
330
Configuring ISDN BRI
330
Configuring ISDN PRI
332
Verifying the ISDN Configuration
334
Troubleshooting the ISDN Configuration 336
DDR Routing
336
DDR Operation
337
Legacy DDR
338
Defining Static Routes for DDR
338
Specifying Interesting Traffic for DDR 339
Configuring DDR Dialer Information 339
Dialer Profiles
341
Configuring Dialer Profiles 342
Verifying the DDR Configuration 342
Summary
344
Key Terms
344
Check Your Understanding
345
Chapter 15
Frame Relay
349
Frame Relay Overview 349
Frame Relay Terminology 350
Frame Relay Operation
351
Frame Relay LMI
354
LMI Operations
354
LMI Extensions
355
Global Addressing
356
Multicasfing
356
Inverse ARP
356
Stages of Inverse ARP and LMI Operation 356
Frame Relay Mapping
357
Frame Relay Switching Tables 357
Frame Relay Operation Summary 358
Frame Relay Subinterfaces
358
Split Horizon Routing Environments 360
Resolving Reachabilty Issues with Subinterfaces
360
Basic Frame Relay Configuration 361
Configuring the Serial Interface 361
Verifying the Serial Interface Configuration 362
Verifying Operation and Confirming Connectivity 362
Confirming That the Line Is Up
363
Confirming the Frame Relay Maps
364
Confirming Connectivity to the Central Site Router
364
Configuring Subinterfaces 364
Configuring Optional Commands 366
Summary
367
Key Terms
368
Check Your Understanding 368
Chapter 16
Introduction to Network Administration 373
Overview of Desktop and Server Operating Systems
373
Workstations
373
Servers
375
Client/Server Relationship
378
NOSs
379
Windows NT, Windows 2000, and Windows .NET
381
UNIX and Linux
383
Macintosh OS X
386
Concept of Service on Servers 387
File Sharing
387
FTP and File Transfer
387
Web Services
388
DNS
388
DHCP
388
Network Management
388
OSI and Network Management Model 389
Standards: SNMP and CMIP 390
SNMP Operation
391
Structure of Management Information and MIBs
393
SNMP Protocol
394
Configuring SNMP
397
RMON
398
Syslog
398
Summary
400
Key Terms
400
Check Your Understanding 400
Part IV CCNA Bonus Material 403
Chapter 17
Optical Networking Fundamentals 405
Basics of Optical Networks
405
Optical Business Drivers
405
Fiber-Optic Systems
406
Fiber-Optic Transmission System 406
Light
407
Optical Fibers
410
Fiber Types
410
Fiber Geometry
411
Attenuation
413
Optical Filters
414
Optical Amplifiers
414
Optical Transmission and Multiplexing 415
SONET Technology
415
SONET Multiplexing Hierarchy
418
DWDM Systems
418
Summary
421
Key Terms
421
Check Your Understanding 422
Chapter 18
Network Management
425
Network Documentation
425
Main Distribution Frame MDF and Intermediate Distribution Frame IDF Layouts 425
Server and Workstation Configuration Details
426
Software Listings
427
Maintenance Records
428
Security Measures
428
User Policies
428
Network Security
429
Data Recovery
429
Backup Operations
430
Redundancy Techniques
431
Environmental Factors
432
Power Conditioning
433
EMI and RFI
433
Software Viruses
433
Network Performance
434
Server Administration
435
Client/Server Network
436
Network Control
438
The Administrative Side of Network Management
439
Understanding and Establishing the Boundaries of the Network
440
Costs of a Network
440
Error Report Documentation
440
Monitoring the Network
441
Connection Monitoring
441
Traffic Monitoring
441
SNMP
442
Remote Monitoring
443
Network Troubleshooting 445
The Troubleshooting Process 445
Troubleshooting Techniques
446
Software Tools
450
Summary
453
Key Terms
454
Chapter 19
Network Certification Exam Review 457
Chapter 20
CCNA Certification Exam Review 459
OSI Model
459
Application Layer
459
Presentation Layer
459
Session Layer
460
Transport Layer
460
Network Layer
460
Data Link Layer
461
Physical Layer
461
Bridging/Switching
461
Full-Duplex and Half-Duplex Ethernet Operations 461
Distinguishing Between Cut-Through and Store-and-Forward LAN Switching 462
The Operation and Benefits of VLANs 463
Routed Protocols
464
Different Classes of IP Addresses, Including Subnetting and Private Addresses 464
Subnetting
465
Converting Among Decimal, Hexadecimal, and Binary
467
Routing Protocols
469
Exterior and Interior Routing Protocols 470
Enabling RIP and IGRP on a Router 472
Identifying Routing Metrics Used by IGRP and RIP
472
Comparing and Contrasting the Key Operations That Distinguish Distance Vector, Link-State, and Hybrid Protocols
473
WAN Protocols
476
Key Frame Relay Terms and Features 476
Differentiating Among LAPB, Frame Relay,ISDN/LAPD, HDLC, PPP, and DDR 476
Configuring ISDN BRI and Legacy Dial-on-Demand Routing DDR
477
Configuration File Management Using TFrP
479
How to Load a Software Image Backup 479
Configuration File Management
480
Managing ItS Images with TFrP
481
Internet Control Message Protocol 482
ICMP Message Delivery
483
Error Reporting and Error Correction 483
Unreachable Networks
483
Using ping to Test Destination Reachability
484
Access Lists
486
ACL Overview
487
Reasons to Create ACLs
487
Cisco Equipment, ItS, and Network Basics 488
Initial Router Boot-Up Output 488
Establishing a HyperTerminal Session 489
Logging In to the Router
489
Keyboard Help
490
1OS Editing Commands
492
Router Command History
493
Troubleshooting Command Errors
493
The Purpose of the Cisco Its 494
Operation of the Cisco Its
494
Cisco ItS Features
494
The show version Command
495
Router User Interface
495
Cisco ItS Troubleshooting 496
Summary
497
Key Terms
497
Chapter 21
Introduction to Converged Networking 501
Traditional Networks
501
Introduction to Voice and Data Networks 501
Voice over Frame Relay
502
Voice over ATM
503
Voice over IP
503
Comparing Voice-over-Data Technologies 504
Voice, Video, and Data Networks 504
Cisco AVVID
505
Converged Networking Applications 505
Common Issues with QoS
508
Delay
508
Jitter
509
Lost Packets
509
Echo
509
Cisco Its Software QoS Technology
510
Summary
510
Key Terms
511
Chapter 22
Developing Network Security and Network Management Strategies
513
Network Security Design
513
Identifying Network Assets and Analyzing Risks
514
Analyzing Security Requirements and TradeOffs
514
Developing a Security Plan
514
Defining a Security Policy 515
Components of a Security Policy 515
Developing Security Procedures 515
Security Mechanisms
516
Authentication
516
Authorization
516
Accounting Auditing
516
Data Encryption
517
Packet Filters
518
Firewalls 519
Intrusion Detection
519
Physical Security
520
Selecting Security Solutions 520
Securing the InternetConnection 520
Securing InternetDomain Name System Services 521
Logical Network Design and the Internet Connection 521
IP Security Protocol
521
Securing Dial-Up Access
522
Securing Network Services
522
Securing User Services
523
Summary
524
Key Terms
524
Chapter 23
Virtual Private Networks 527
VPN Operation
527
VPN Advantages
527
Types of VPNs
528
Service-Level Agreements
528
An Example VPN
529
VPNs of Network A Sites 529
VPN Implementation
530
Security Audit
530
The Scope and Application Needs
530
Documentation
530
Security Policy
530
The Cisco Systems VPN Design 531
Tunneling Overview
531
Cisco Virtual Dial-Up Services 532
Cisco L2TP Implementation 532
End-to-End Virtual Dial-Up Process 533
Highlights of Virtual Dial-Up Service 534
Authentication and Security 534
Authorization
534
Address Allocation
534
Accounting
534
Summary
536
Key Terms
536
Part V Appendixes
539
Appendix A
Glossary of Key Terms 540
Appendix B
Check Your Understanding Answer Key 541
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