CompTIA Network+ Exam N10 005 Training Kit
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CompTIA Network+: Exam N10-005
Objective
chapter
1.0
1.1
1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
NetwOrk cONcepts (21 perceNt)
Compare the layers of the OSI and TCP/IP models: OSI model (Layer 1 – Physical, Layer 2 – Data link,
Layer 3 – Network, Layer 4 – Transport, Layer 5 – Session, Layer 6 – Presentation, Layer 7 – Application); TCP/IP model (Network Interface Layer, Internet Layer, Transport Layer, Application Layer
[Also described as: Link Layer, Internet Layer, Transport Layer, Application Layer])
Classify how applications, devices, and protocols relate to the OSI model layers: MAC address; IP
address; EUI-64; Frames; Packets; Switch; Router; Multilayer switch; Hub; Encryption devices; Cable;
NIC; Bridge
Explain the purpose and properties of IP addressing: Classes of addresses (A, B, C and D, Public vs.
Private); Classless (CIDR); IPv4 vs. IPv6 (formatting); MAC address format; Subnetting; Multicast vs.
unicast vs. broadcast; APIPA
Explain the purpose and properties of routing and switching: EIGRP; OSPF; RIP; Link state vs.
distance vector vs. hybrid; Static vs. dynamic; Routing metrics (Hop counts, MTU, bandwidth, Costs,
Latency); Next hop; Spanning-Tree Protocol; VLAN (802.1q); Port mirroring; Broadcast domain vs.
collision domain; IGP vs. EGP; Routing tables; Convergence (steady state)
Identify common TCP and UDP default ports: SMTP – 25; HTTP – 80; HTTPS – 443; FTP – 20, 21;
TELNET – 23; IMAP – 143; RDP – 3389; SSH – 22; DNS – 53; DHCP – 67, 68
Explain the function of common networking protocols: TCP; FTP; UDP; TCP/IP suite; DHCP; TFTP;
DNS; HTTPS; HTTP; ARP; SIP (VoIP); RTP (VoIP); SSH; POP3; NTP; IMAP4; Telnet; SMTP; SNMP2/3;
ICMP; IGMP; TLS
Summarize DNS concepts and its components: DNS servers; DNS records (A, MX, AAAA, CNAME,
PTR); Dynamic DNS
Given a scenario, implement the following network troubleshooting methodology: Identify the
problem (Information gathering, Identify symptoms, Question users, Determine if anything has
changed); Establish a theory of probable cause (Question the obvious); Test the theory to determine cause (Once theory is confirmed determine next steps to resolve problem; If theory is not
confirmed, re-establish new theory or escalate); Establish a plan of action to resolve the problem
and identify potential effects; Implement the solution or escalate as necessary; Verify full system
functionality and if applicable implement preventative measures; Document findings, actions and
outcomes
Identify virtual network components: Virtual switches; Virtual desktops; Virtual servers; Virtual PBX;
Onsite vs. offsite; Network as a Service (NaaS)
NetwOrk iNstaLLatiON aND cONFiGUratiON (23 perceNt)
Given a scenario, install and configure routers and switches: Routing tables; NAT; PAT; VLAN (trunking); Managed vs. unmanaged; Interface configurations (Full duplex, Half duplex, Port speeds, IP
addressing, MAC filtering); PoE; Traffic filtering; Diagnostics; VTP configuration; QoS; Port mirroring
Given a scenario, install and configure a wireless network: WAP placement; Antenna types; Interference; Frequencies; Channels; Wireless standards; SSID (enable/disable); Compatibility (802.11
a/b/g/n)
Explain the purpose and properties of DHCP: Static vs. dynamic IP addressing; Reservations; Scopes;
Leases; Options (DNS servers, suffixes)
Given a scenario, troubleshoot common wireless problems: Interference; Signal strength; Configurations; Incompatibilities; Incorrect channel; Latency; Encryption type; Bounce; SSID mismatch;
Incorrect switch placement
Given a scenario, troubleshoot common router and switch problems: Switching loop; Bad cables/
improper cable types; Port configuration; VLAN assignment; Mismatched MTU/MTU black hole;
Power failure; Bad/missing routes; Bad modules (SFPs, GBICs); Wrong subnet mask; Wrong gateway;
Duplicate IP address; Wrong DNS
Given a set of requirements, plan and implement a basic SOHO network: List of requirements;
Cable length; Device types/requirements; Environment limitations; Equipment limitations; Compatibility requirements
1, 3, 6, 7
6
7
8
4, 6, 8, 9, 12
9
13
12
7
5
9
13
13
3, 4
exam Objectives The exam objectives listed here are current as of this book’s publication date. Exam objectives
are subject to change at any time without prior notice and at CompTIA’s sole discretion. Please visit the CompTIA
Certifications webpage for the most current listing of exam objectives: http://certification.comptia.org/getCertified/
certifications.aspx.
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Objective
chapter
3.0
3.1
2
3.2
3.3
3.4
3.5
3.6
3.7
3.8
4.0
4.1
4.2
4.3
4.4
4.5
4.6
5.0
5.1
5.2
5.3
5.4
5.5
5.6
NetwOrk meDia aND tOpOLOGies (17 perceNt)
Categorize standard media types and associated properties: Fiber (Multimode, Singlemode); Copper (UTP, STP, CAT3, CAT5, CAT5e, CAT6, CAT6a, Coaxial, Crossover, T1 Crossover, Straight-through);
Plenum vs. non-plenum; Media converters (Singlemode fiber to Ethernet, Multimode fiber to Ethernet, Fiber to Coaxial, Singlemode to multimode fiber); Distance limitations and speed limitations;
Broadband over powerline
Categorize standard connector types based on network media: Fiber (ST, SC, LC, MTRJ); Copper
(RJ-45, RJ-11, BNC, F-connector, DB-9 [RS-232], Patch panel, 110 block [T568A, T568B])
Compare and contrast different wireless standards: 802.11 a/b/g/n standards (Distance, Speed,
Latency, Frequency, Channels, MIMO, Channel bonding)
Categorize WAN technology types and properties: Types (T1/E1, T3/E3, DS3, OCx, SONET, SDH,
DWDM, Satellite, ISDN, Cable, DSL, Cellular, WiMAX, LTE, HSPA+, Fiber, Dialup, PON, Frame relay,
ATMs); Properties (Circuit switch, Packet switch, Speed, Transmission media, Distance)
Describe different network topologies: MPLS; Point to point; Point to multipoint; Ring; Star; Mesh;
Bus; Peer-to-peer; Client-server; Hybrid
Given a scenario, troubleshoot common physical connectivity problems: Cable problems (Bad
connectors; Bad wiring; Open; short; Split cables; DB loss; TXRX reversed; Cable placement; EMI/
Interference; Distance; Cross-talk)
Compare and contrast different LAN technologies: Types (Ethernet, 10BaseT, 100BaseT, 1000BaseT,
100BaseTX, 100BaseFX, 1000BaseX, 10GBaseSR, 10GBaseLR, 10GBaseER, 10GBaseSW, 10GBaseLW,
10GBaseEW, 10GBaseT); Properties (CSMA/CD, CSMA/CA, Broadcast, Collision, Bonding, Speed,
Distance)
Identify components of wiring distribution: IDF, MDF, Demarc, Demarc extension, Smart jack, CSU/
DSU
NetwOrk maNaGemeNt (20 perceNt)
Explain the purpose and features of various network appliances: Load balancer; Proxy server; Content filter; VPN concentrator
Given a scenario, use appropriate hardware tools to troubleshoot connectivity issues: Cable tester;
Cable certifier; Crimper; Butt set; Toner probe; Punch down tool; Protocol analyzer; Loop back plug;
TDR; OTDR; Multimeter; Environmental monitor
Given a scenario, use appropriate software tools to troubleshoot connectivity issues: Protocol analyzer; Throughput testers; Connectivity software; Ping; Tracert/traceroute; Dig; Ipconfig/ifconfig;
Nslookup; Arp; Nbtstat; Netstat; Route
Given a scenario, use the appropriate network monitoring resource to analyze traffic: SNMP;
SNMPv2; SNMPv3; Syslog; System logs; History logs; General logs; Traffic analysis; Network sniffer
Describe the purpose of configuration management documentation: Wire schemes; Network maps;
Documentation; Cable management; Asset management; Baselines; Change management
Explain different methods and rationales for network performance optimization: Methods (QoS,
Traffic shaping, Load balancing, High availability, Caching engines, Fault tolerance, CARP); Reasons
(Latency sensitivity, High bandwidth applications [VoIP, video applications, unified communications], Uptime)
NetwOrk secUritY (19 perceNt)
Given a scenario, implement appropriate wireless security measures: Encryption protocols (WEP,
WPA, WPA2, WPA Enterprise); MAC address filtering; Device placement; Signal strength
Explain the methods of network access security: ACL (MAC filtering, IP filtering, Port filtering);
Tunneling and encryption (SSL VPN, VPN, L2TP, PPTP, IPSec, ISAKMP, TLS, TLS2.0, Site-to-site and
client-to-site); Remote access (RAS, RDP, PPPoE, PPP, ICA, SSH)
Explain methods of user authentication: PKI; Kerberos; AAA (RADIUS, TACACS+); Network access
control (802.1x, posture assessment); CHAP; MS-CHAP; EAP; Two-factor authentication; Multifactor
authentication; Single sign-on
Explain common threats, vulnerabilities, and mitigation techniques: Wireless (War driving, War
chalking, WEP cracking, WPA cracking, Evil twin, Rogue access point); Attacks (DoS, DDoS, Man in
the middle, Social engineering, Virus, Worms, Buffer overflow, Packet sniffing, FTP bounce, Smurf);
Mitigation techniques (Training and awareness, Patch management, Policies and procedures,
Incident response)
Given a scenario, install and configure a basic firewall: Types (Software and hardware firewalls); Port
security; Stateful inspection vs. packet filtering; Firewall rules (Block/allow, Implicit deny, ACL); NAT/
PAT; DMZ
Categorize different types of network security appliances and methods: IDS and IPS (Behavior
based, Signature based, Network based, Host based); Vulnerability scanners (NESSUS, NMAP);
Methods (Honeypots, Honeynets)
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13
12
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11
4, 10, 11
11
11
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11
CompTIA Network+
Exam N10-005
Training Kit
Craig Zacker
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Published with the authorization of Microsoft Corporation by:
O’Reilly Media, Inc.
1005 Gravenstein Highway North
Sebastopol, California 95472
Copyright © 2012 by Craig Zacker
All rights reserved. No part of the contents of this book may be reproduced
or transmitted in any form or by any means without the written permission of
the publisher.
ISBN: 978-0-7356-6275-9
1 2 3 4 5 6 7 8 9 QG 7 6 5 4 3 2
Printed and bound in the United States of America.
Microsoft Press books are available through booksellers and distributors
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Microsoft and the trademarks listed at http://www.microsoft.com/about/legal/
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Microsoft group of companies. All other marks are property of their respective owners.
The example companies, organizations, products, domain names, email addresses, logos, people, places, and events depicted herein are fictitious. No
association with any real company, organization, product, domain name,
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production editor: Holly Bauer
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copyeditor: Kathy Krause, Online Training Solutions, Inc.
indexer: Angela Howard
cover Design: Twist Creative • Seattle
cover composition: Karen Montgomery
illustrator: Rebecca Demarest
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Contents at a Glance
Introduction
xix
ChApTEr 1
Networking Basics
1
ChApTEr 2
The physical Layer
43
ChApTEr 3
Network Devices
101
ChApTEr 4
The Data-Link Layer
141
ChApTEr 5
Wireless Networking
191
ChApTEr 6
The Network Layer
229
ChApTEr 7
routing and Switching
291
ChApTEr 8
The Transport Layer
339
ChApTEr 9
The Application Layer
369
ChApTEr 10
Wide Area Networking
445
ChApTEr 11
Network Security
483
ChApTEr 12
Network Management
541
ChApTEr 13
Network Troubleshooting
583
Glossary
637
Index
655
About the Author
681
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Contents
introduction
chapter 1
xix
System Requirements
xix
Using the Companion CD
xx
Support & Feedback
xxi
Preparing for the Exam
xxii
Networking basics
1
Network Communications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
LANs and WANs
3
Signals and Protocols
5
Packet Switching and Circuit Switching
8
Client/Server and Peer-to-Peer Networks
9
The OSI Reference Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Protocol Interaction
12
Data Encapsulation
13
The Physical Layer
16
The Data-Link Layer
18
The Network Layer
22
The Transport Layer
25
The Session Layer
29
The Presentation Layer
31
The Application Layer
32
What do you think of this book? We want to hear from you!
Microsoft is interested in hearing your feedback so we can continually improve our
books and learning resources for you. To participate in a brief online survey, please visit:
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vii
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The TCP/IP Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
The Link Layer
35
The Internet Layer
36
The Transport Layer
36
The Application Layer
37
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
chapter 2
Exercise
40
Chapter Review
40
the physical Layer
43
Cables and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Copper Cable Types
46
Fiber Optic Cable
55
Power Line Networking
57
Media Converters
58
Topologies and Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Cable Topologies
59
Multiprotocol Label Switching
67
Cabling Standards
68
Installing Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Installing External Cables
70
Installing Internal Cables
73
Connecting to the Backbone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
viii
Exercise
99
Chapter Review
99
contents
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chapter 3
Network Devices
101
Network Interface Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Network Interface Adapter Functions
108
Optional Network Adapter Functions
109
Purchasing Network Interface Adapters
112
Installing a Network Interface Adapter
114
Troubleshooting a Network Interface Adapter
116
At the Other End of the Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Using Repeaters
117
Using Hubs
118
Using Bridges
122
Using Routers
124
Using Switches
129
Using Multifunction Devices
135
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
chapter 4
Exercise
139
Chapter Review
139
the Data-Link Layer
141
Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Ethernet Standards
143
Ethernet Components
145
Point-to-Point Protocol (PPP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
PPP Standards
170
The PPP Frame
171
Authentication Protocols
175
The IPCP Frame
176
PPP Connection Establishment
177
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ix
Address Resolution Protocol (ARP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
ARP Message Format
181
ARP Transactions
183
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
chapter 5
Exercise
189
Chapter Review
190
wireless Networking
191
Wireless LAN Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Building a Wireless Standard
193
IEEE 802.11 Standards
194
Wireless LAN Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
The Physical Layer
201
The Data-Link Layer
210
Installing a Wireless LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Examining the Site
215
Selecting Hardware
217
Installing and Configuring Wireless Hardware
222
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
chapter 6
Exercise
226
Chapter Review
226
the Network Layer
229
Internet Protocol (IP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
x
IP Standards
231
IP Versions
232
IP Functions
233
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IPv4 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
IPv4 Address Assignments
235
IPv4 Address Classes
236
IPv4 Address Types
237
Subnet Masking
238
Classless Inter-Domain Routing
243
Registered and Unregistered Addresses
245
Obtaining IP Addresses
247
Assigning IPv4 Addresses
248
IPv6 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
IPv6 Address Types
251
IPv6 Address Assignment
260
Data Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
The IPv4 Datagram Format
264
The IPv6 Datagram Format
268
IPv4 Fragmentation
271
IPv6 Fragmentation
272
IP Routing
273
Internet Control Message Protocol (ICMP) . . . . . . . . . . . . . . . . . . . . . . . . . 273
ICMPv4
273
ICMPv6
280
Internet Group Management Protocol (IGMP) . . . . . . . . . . . . . . . . . . . . . . 283
Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
Scenario #1
285
Scenario #2
285
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Exercises
288
Chapter Review
288
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xi
chapter 7
routing and switching
291
Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
What Is Routing?
293
Router Functions
294
Router Products
297
Understanding Routing Tables
298
Routing in IPv6
308
Routing and ICMP
308
Routing and Network Address Translation
309
Static and Dynamic Routing
313
Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
Routing vs. Switching
328
Configuring VLAN Trunking Protocol (VTP)
332
Power Over Ethernet (PoE)
333
Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Scenario #1
334
Scenario #2
334
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
chapter 8
Exercises
337
Chapter Review
337
the transport Layer
339
Transmission Control Protocol (TCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
The TCP Header
341
TCP Options
343
TCP Communications
345
User Datagram Protocol (UDP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
Ports and Sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
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Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
chapter 9
Exercise
366
Chapter Review
366
the application Layer
369
Application Layer Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
DHCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
DHCP Origins
371
DHCP Objectives
372
IP Address Assignment
374
Creating Scopes
375
TCP/IP Client Configuration
375
DHCP Packet Structure
376
DHCP Options
378
DHCP Communications
380
Relay Agents
388
DHCPv6
389
DNS 395
Host Tables
395
DNS Objectives
396
Domain Naming
398
Resource Records
404
DNS Messaging
405
DNS Name Resolution
406
Reverse Name Resolution
412
DNS Name Registration
414
Zone Transfers
416
HTTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
HTTP Requests
418
HTTP Responses
419
HTTP Message Exchanges
420
HTTPS
422
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xiii
FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
FTP Commands
423
FTP Messaging
424
TFTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
Telnet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
Email . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
Email Addressing
428
Email Clients and Servers
428
SMTP
430
POP3
433
IMAP
435
NTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
Exercise
442
Chapter Review
442
chapter 10 wide area Networking
445
What Is a WAN? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .446
Connecting to the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .448
Public Switched Telephone Network
448
Integrated Services Digital Network (ISDN)
450
Digital Subscriber Line (DSL)
452
Cable Television (CATV) Networks
454
Satellite-Based Services
455
Last Mile Fiber
456
Cellular Technologies
457
Connecting LANs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
xiv
Leased Lines
460
SONET/SDH
463
Packet Switching
465
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Remote Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
Dial-up Remote Access
469
Virtual Private Networking
470
SSL VPN
475
Using a VPN Concentrator
475
Remote Terminal Emulation
475
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
Exercise
480
Chapter Review
480
chapter 11 Network security
483
Authentication and Authorization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
Network Authentication Systems
486
Authentication Protocols
493
Tunneling and Encryption Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
IPsec
501
SSL and TLS
507
Wireless Security Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
WEP
509
802.1X
511
WPA
512
Other Wireless Security Techniques
513
Firewalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
Packet Filtering
516
Stateful Packet Inspection
520
Firewall Implementations
521
Creating a Peripheral Network
525
Other Security Appliances
526
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xv
Security Threats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
Denial of Service
529
Man in the Middle
529
Malware
530
Buffer Overflow
531
Social Engineering
531
Wireless Threats
532
Mitigation Techniques
533
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
Exercise
538
Chapter Review
538
chapter 12 Network management
541
Network Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
Cable Diagrams
543
Network Diagrams
544
Network Maps
546
Hardware Configurations
546
Change Management
547
Baselines
547
Network Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
Logs
xvi
549
SNMP
556
Protocol Analyzers
558
Port Scanners
563
Vulnerability Scanners
565
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Virtualization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
Virtualization Architectures
567
Desktop Virtualization
569
Virtual Switching
570
Presentation Virtualization
570
Application Virtualization
571
Virtual PBXes
571
Performance Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572
Caching Data
573
Traffic Control
574
Redundant Services
575
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
Exercise
581
Chapter Review
581
chapter 13 Network troubleshooting
583
Troubleshooting Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
The Ping Program
585
Traceroute
586
Ifconfig and Ipconfig.exe
588
ARP
589
Netstat
590
Nbtstat.exe
594
Nslookup
595
Dig
596
Route
597
What do you think of this book? We want to hear from you!
Microsoft is interested in hearing your feedback so we can continually improve our
books and learning resources for you. To participate in a brief online survey, please visit:
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contents
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xvii
Troubleshooting Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
Identify the Problem
598
Establish a Theory
601
Test the Theory
601
Establish a Plan of Action
602
Implement the Solution
603
Verify System Functionality
603
Document Findings
604
Troubleshooting Connectivity Issues
605
Troubleshooting Wireless Problems
606
Troubleshooting Router and Switch Problems
607
Network Troubleshooting Scenario: “I Can’t Access a Website” . . . . . . . . 612
Incident Administration
612
Gathering Information
613
Possible Cause: Internet Router Problem
614
Possible Cause: Internet Communication Problem
616
Possible Cause: DNS Failure
617
Possible Cause: LAN Communications Problem
622
Possible Cause: Computer Configuration Problem
626
Possible Cause: User Error
630
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634
xviii
Exercise
634
Chapter Review
634
Glossary
637
Index
655
contents
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Introduction
This training kit is designed for information technology (IT) professionals who support or plan
to support networks and who also plan to take the CompTIA Network+ exam. It is assumed
that before you begin using this kit, you have a CompTIA A+ certification or the equivalent
knowledge, as well as 9 to 12 months of work experience in IT networking.
The material covered in this training kit and on the Network+ exam relates to the technologies in a network that support distributed access to web content, media, operating systems,
and applications. The topics in this training kit cover what you need to know for the exam as
described on the Certification Exam Objectives document for the exam, which is available at:
http://certification.comptia.org/getCertified/certifications/network.aspx
By using this training kit, you will learn how to do the following:
■
Use the Open Systems Interconnection (OSI) reference model to understand network
processes.
■
Install and maintain the various cables and other media used to build networks.
■
Understand the protocols that networked computers use to communicate.
■
Understand how routers and switches connect network devices to each other and to
other networks.
■
Connect to distant networks by using wide area network (WAN) technologies.
■
Secure a network by using firewalls and other tools.
■
Use network monitoring and diagnostic tools.
■
Troubleshoot network problems in a systematic and logical manner.
Refer to the objective mapping page in the front of this book to see where in the book
each exam objective is covered.
system requirements
CompTIA suggests you have access to various hardware and software to help you prepare for
the Network+ exam. The items include equipment, spare hardware, spare parts, tools, software, and other items you might need. You’ll find a list of items at the back of the CompTIA
Network+ Certification Exam Objectives: N10-005 guide, which you can download from
the CompTIA website. Please visit http://certification.comptia.org/getCertified/certifications/
network.aspx for more information.
xix
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Using the companion cD
A companion CD is included with this training kit. The companion CD contains the following:
■
practice tests You can reinforce your understanding of the topics covered in this
training kit by using electronic practice tests that you customize to meet your needs.
You can practice for the Network+ certification exam by using tests created from a
pool of 200 realistic exam questions, which give you many practice exams to ensure
that you are prepared.
■
an ebook An electronic version (eBook) of this book is included for when you do not
want to carry the printed book with you.
Note
cOmpaNiON cONteNt FOr DiGitaL bOOk reaDers
If you bought a digital-only edition of this book, you can enjoy select content from the
print edition’s companion CD. Visit http://go.microsoft.com/FWLink/?Linkid=248373 to get
your downloadable content.
how to Install the practice Tests
To install the practice test software from the companion CD to your hard disk, perform the
following steps:
1.
Insert the companion CD into your CD drive and accept the license agreement. A CD
menu appears.
Note
iF the cD meNU DOes NOt appear
If the CD menu or the license agreement does not appear, Autorun might be disabled
on your computer. Refer to the Readme.txt file on the CD for alternate installation
instructions.
2.
Click Practice Tests and follow the instructions on the screen.
xx introduction
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how to Use the practice Tests
To start the practice test software, follow these steps:
1.
Click Start, All Programs, and then select Microsoft Press Training Kit Exam Prep.
2.
A window appears that shows all the Microsoft Press training kit exam prep suites
installed on your computer.
3.
Double-click the practice test you want to use.
When you start a practice test, you choose whether to take the test in Certification Mode,
Study Mode, or Custom Mode:
■
Certification Mode Closely resembles the experience of taking a certification exam.
The test has a set number of questions. It is timed, and you cannot pause and restart
the timer.
■
study mode Creates an untimed test during which you can review the correct answers and the explanations after you answer each question.
■
custom mode Gives you full control over the test options so that you can customize
them as you like.
In all modes, the user interface when you are taking the test is basically the same but with
different options enabled or disabled depending on the mode.
When you review your answer to an individual practice test question, a “References” section is provided that lists where in the training kit you can find the information that relates to
that question. After you click Test Results to score your entire practice test, you can click the
Learning Plan tab to see a list of references for every objective.
how to Uninstall the practice Tests
To uninstall the practice test software for a training kit, use the Programs And Features option
in Control Panel.
support & Feedback
The following sections provide information on errata, book support, feedback, and contact
information.
introduction xxi
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Errata & Book Support
We’ve made every effort to ensure the accuracy of this book and its companion content. Any
errors that have been reported since this book was published are listed on our Microsoft Press
site at oreilly.com:
http://go.microsoft.com/FWLink/?Linkid=248372
If you find an error that is not already listed, you can report it to us through the
same page.
If you need additional support, email Microsoft Press Book Support at:
mspinput@microsoft.com
Please note that product support for Microsoft software is not offered through the
addresses above.
We Want to hear from You
At Microsoft Press, your satisfaction is our top priority, and your feedback is our most
valuable asset. Please tell us what you think of this book at:
http://www.microsoft.com/learning/booksurvey
The survey is short, and we read every one of your comments and ideas. Thanks in
advance for your input!
Stay in Touch
Let’s keep the conversation going! We are on Twitter: http://twitter.com/MicrosoftPress.
preparing for the exam
CompTIA certification exams are a great way to build your resume and let the world know
about your level of expertise. Certification exams validate your on-the-job experience and
product knowledge. Although there is no substitute for on-the-job experience, preparation
through study and hands-on practice can help you prepare for the exam. We recommend
that you augment your exam preparation plan by using a combination of available study
materials and courses. For example, you might use the Training Kit and another study guide
for your “at home” preparation, and take a CompTIA professional certification course for the
classroom experience. Choose the combination that you think works best for you.
xxii introduction
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chapter 1
Networking Basics
T
his chapter introduces the fundamental computer networking concepts that form the basis for all of the questions on
the CompTIA Network+ examination. You might be inclined to
skip around in this book during your exam preparation regimen,
but you should make sure that you understand the principles in
this chapter before you do so. Otherwise, you might find yourself struggling later, both in the exam room and on the job.
imp ortant
Have you read
page xxii?
It contains valuable
information regarding
the skills you need to
pass the exam.
Exam objectives in this chapter:
Objective 1.1: Compare the layers of the OSI and TCP/IP models.
■
OSI model:
■
TCP/IP model:
●
Layer 1 – Physical
●
Network Interface Layer
●
Layer 2 – Data link
●
Internet Layer
●
Layer 3 – Network
●
Transport Layer
●
Layer 4 – Transport
●
Application Layer
●
Layer 5 – Session
●
Layer 6 – Presentation
●
Layer 7 – Application
❍
(Also described as: Link Layer,
Internet Layer, Transport Layer,
Application Layer)
Objective 1.2: Classify how applications, devices, and protocols relate to the OSI model layers.
■
MAC address
■
Multilayer switch
■
IP address
■
Hub
■
EUI-64
■
Encryption devices
■
Frames
■
Cable
■
Packets
■
NIC
■
Switch
■
Bridge
■
Router
1
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ReAL WoRLD
reiNveNtiNG NetwOrk+
Anyone familiar with the earlier incarnations of the CompTIA Network+ examination might
notice that there are some rather profound differences between the objectives tested by
the N10-004 version of 2009 and those in the N10-005 version released in late 2011. Some
of these changes are representative of the latest developments in networking technology,
and others demonstrate a definite change in the focus of the exam.
First, and most obvious, is the elimination of many technologies that have lapsed into
obsolescence. With Ethernet now unquestionably the dominant data-link layer protocol
on the desktop, older protocols such as Token ring and Fiber Distributed Data Interface
(FDDI), which were included in the 2005 edition of the objectives, are now gone. Conversely,
the 802.11 wireless LAN standards that barely rated a mention in 2005 and received two
objectives in 2009 now have four, making them a major part of the exam.
At the network and transport layers, TCp/Ip is now ubiquitous, displacing older alternatives
such as IpX/SpX, NetBEUI, and AppleTalk. This is not to say that you will never encounter
any of these protocols in the field ever again, but they are now considered rare, if not actually endangered, species.
Whereas the 2005 objectives specified the need for basic knowledge of various server
operating systems, the 2009 and 2011 objectives place far more concentration on specific
areas of network support, such as configuration management, performance optimization,
and troubleshooting methodologies. The operating system names no longer appear in the
objectives at all.
The 2011 objectives also clarify the examination’s emphasis on infrastructure management.
New objectives single out services such as DNS and DhCp for particular concentration and
deemphasize hardware and software technologies that are fading from general use.
Network communications
What is a data network? Simply put, a data network is an array of computers and other devices
connected together by a common medium that enables them to communicate with each
other. That common medium can be wired, using copper or fiber optic cables; wireless, using
infrared or radio signals; or connected to a service provider, such as a telephone or cable television network. A data network can be as simple as two home computers connected together,
or as complex as the Internet, joining millions of computers together around the world.
Why connect computers together? The two primary reasons to create data networks are to:
2
■
Share hardware
■
Share data
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Networking Basics
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In the early days of the PC, the only way to print a document was to connect a printer
directly to a computer. As more and more companies adopted the PC as a business tool, it
became impractical to buy a printer for every computer or to move a single printer from
computer to computer as needed. By connecting computers to a network, they could share a
single printer.
Key
In the same way, networking made it possible for computers to share data. Rather
than save a document file to a removable disk and walk it to another computer—a process
colloquially known as the sneakernet—users could store files on a common server, enabling
anyone to access them. As networks grew larger and more complex, so did the applications
that made use of them. Today, in addition to document files and printer jobs, networks carry
data in the form of email messages, webpages, video streams, and many other types.
LANs and WANs
Key
The earliest PC networks used copper-based cables as the network medium, and many still
do. A local area network (LAN) is a group of computers or other devices that share a common
location, such as a room, a floor, or a building; and a common network medium, such as a
particular type of cable. The medium interconnects the computers so that they are capable of
sharing data with each other. LANs can include network connection devices, such as switches
and routers, and are also characterized by their relatively high data transmission rates and
their ability to function without the need for outside service providers.
A typical small LAN is shown in Figure 1-1. LANs are wholly owned by an organization and
require no licensing or registration. Anyone can purchase the hardware required and assemble a LAN in his or her home or office.
FiGUre 1-1 A typical small LAN.
Key
Devices connected to a LAN, such as computers or printers, are generically referred to as
nodes. A 50-node network is therefore a single network medium with 50 computers or other
devices connected to it.
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chapter 1
3
exAm tip
Virtually all of the wired LANs installed today use a technology known as Ethernet or, more
precisely, IEEE 802.3. There are several other antiquated LAN technologies, including Token
ring and FDDI, that are no longer covered by the Network+ exam, and for which products
are no longer available on the market, but that you might conceivably encounter in older
installations.
Key
LANs are expandable within certain limits imposed by the protocols they use to communicate, but in large installations, it is often necessary to connect multiple LANs together. To
do this, you use a device called a router, as shown in Figure 1-2. A router is simply a device
that connects networks together, forming what is known as a “network of networks” or, more
commonly, an “internetwork.”
Router
FiGUre 1-2 Two LANs connected by a router.
Note
internet or internet?
Do not confuse the terms “internetwork” or “internet” (with a lowercase “i”) with the Internet (with a capital “I”). The term “Internet” describes a specific example of that for which
“internetwork” is the generic designation. In other words, the Internet is a specific type of
internetwork, but not every use of the term “internetwork” refers to the Internet.
Key
4
A wide area network (WAN) is a group of computers connected by a longer distance
communication technology provided by a third-party service provider, such as a telephone
company. Internet connections for LANs or individual computers, whether they use dial-up
modems and telephone lines or broadband technologies, are all WAN links. Corporate networks also use WAN technologies to connect offices at remote sites together. Most WAN connections are point-to-point links joining two sites together; a company with multiple branch
offices in different cities might have separate WAN links connecting each branch to the main
office. As with LANs, WANs are connected together by routers, as shown in Figure 1-3.
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Router
Router
WAN Link
FiGUre 1-3 Two LANs connected by a WAN link.
moRe iNfo
waN techNOLOGies
For more information on the various types of WAN technologies currently in use, see
Chapter 10, “Wide Area Networking.”
WAN connections can take many forms and use many different communications technologies. Subscribers, whether private individuals or large companies, can choose from among
a variety of WAN providers offering connections with different speeds and services. Generally speaking, WAN connections are much slower than LAN connections and are far more
expensive. Most LANs today run at 100 or 1,000 megabits per second (Mbps), and the only
costs involved are for the required hardware components. WAN connections typically run at
speeds of up to 4 Mbps for residential Internet connections, and up to 25 Mbps for business
connections. Very few even approach the speed of a modest LAN. Subscription prices vary
depending on the speed of the connection and the other services provided.
Signals and protocols
All of the computers connected to a network communicate by exchanging signals with each
other. The nature of the signals depends on the network medium. The three most common
types of signals used for network communications are as follows:
■
electrical Networks that use copper-based cables as a medium communicate by using electrical signals, voltages generated by the transceiver in each node.
■
Light Fiber optic cables carry signals in the form of pulses of light, and some wireless
networks use infrared light as a signaling medium.
■
radio Most wireless networks communicate by using radio signals.
In each of these cases, the signals form a simple code that enables the computers to
transmit data over the network. At the signaling level, network communications are extremely
simple, consisting only of positive or negative voltages, the presence or absence of light, or
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chapter 1
5
specific radio frequency variations. The process by which complex data structures, such as
print jobs, email messages, and video streams, get reduced to simple signals is the responsibility of software components called protocols, which run on each computer.
Protocols are essentially languages that operate at various levels of the networking software on each computer or other device. Just as two people must speak the same language
to be able to talk to each other, two computers on the same network must use the same
protocols to communicate. Unlike human speech, however, which uses a single language, a
networked computer uses multiple protocols in layers, forming a construction known as a
protocol stack.
Key
The signals that the computer transmits over the network medium are at the bottom of
the stack, and the applications that handle the data are at the top, as shown in Figure 1-4.
One of the primary functions of the protocol stack is to reduce the data generated by the
applications running on the computer down to the simple signals suitable for the network
medium. When the signals arrive at their destination, the protocol stack performs the same
process in reverse, interpreting the incoming signals and restoring them to their original form.
Application
Protoco
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CompTIA Network+: Exam N10-005
Objective
chapter
1.0
1.1
1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
NetwOrk cONcepts (21 perceNt)
Compare the layers of the OSI and TCP/IP models: OSI model (Layer 1 – Physical, Layer 2 – Data link,
Layer 3 – Network, Layer 4 – Transport, Layer 5 – Session, Layer 6 – Presentation, Layer 7 – Application); TCP/IP model (Network Interface Layer, Internet Layer, Transport Layer, Application Layer
[Also described as: Link Layer, Internet Layer, Transport Layer, Application Layer])
Classify how applications, devices, and protocols relate to the OSI model layers: MAC address; IP
address; EUI-64; Frames; Packets; Switch; Router; Multilayer switch; Hub; Encryption devices; Cable;
NIC; Bridge
Explain the purpose and properties of IP addressing: Classes of addresses (A, B, C and D, Public vs.
Private); Classless (CIDR); IPv4 vs. IPv6 (formatting); MAC address format; Subnetting; Multicast vs.
unicast vs. broadcast; APIPA
Explain the purpose and properties of routing and switching: EIGRP; OSPF; RIP; Link state vs.
distance vector vs. hybrid; Static vs. dynamic; Routing metrics (Hop counts, MTU, bandwidth, Costs,
Latency); Next hop; Spanning-Tree Protocol; VLAN (802.1q); Port mirroring; Broadcast domain vs.
collision domain; IGP vs. EGP; Routing tables; Convergence (steady state)
Identify common TCP and UDP default ports: SMTP – 25; HTTP – 80; HTTPS – 443; FTP – 20, 21;
TELNET – 23; IMAP – 143; RDP – 3389; SSH – 22; DNS – 53; DHCP – 67, 68
Explain the function of common networking protocols: TCP; FTP; UDP; TCP/IP suite; DHCP; TFTP;
DNS; HTTPS; HTTP; ARP; SIP (VoIP); RTP (VoIP); SSH; POP3; NTP; IMAP4; Telnet; SMTP; SNMP2/3;
ICMP; IGMP; TLS
Summarize DNS concepts and its components: DNS servers; DNS records (A, MX, AAAA, CNAME,
PTR); Dynamic DNS
Given a scenario, implement the following network troubleshooting methodology: Identify the
problem (Information gathering, Identify symptoms, Question users, Determine if anything has
changed); Establish a theory of probable cause (Question the obvious); Test the theory to determine cause (Once theory is confirmed determine next steps to resolve problem; If theory is not
confirmed, re-establish new theory or escalate); Establish a plan of action to resolve the problem
and identify potential effects; Implement the solution or escalate as necessary; Verify full system
functionality and if applicable implement preventative measures; Document findings, actions and
outcomes
Identify virtual network components: Virtual switches; Virtual desktops; Virtual servers; Virtual PBX;
Onsite vs. offsite; Network as a Service (NaaS)
NetwOrk iNstaLLatiON aND cONFiGUratiON (23 perceNt)
Given a scenario, install and configure routers and switches: Routing tables; NAT; PAT; VLAN (trunking); Managed vs. unmanaged; Interface configurations (Full duplex, Half duplex, Port speeds, IP
addressing, MAC filtering); PoE; Traffic filtering; Diagnostics; VTP configuration; QoS; Port mirroring
Given a scenario, install and configure a wireless network: WAP placement; Antenna types; Interference; Frequencies; Channels; Wireless standards; SSID (enable/disable); Compatibility (802.11
a/b/g/n)
Explain the purpose and properties of DHCP: Static vs. dynamic IP addressing; Reservations; Scopes;
Leases; Options (DNS servers, suffixes)
Given a scenario, troubleshoot common wireless problems: Interference; Signal strength; Configurations; Incompatibilities; Incorrect channel; Latency; Encryption type; Bounce; SSID mismatch;
Incorrect switch placement
Given a scenario, troubleshoot common router and switch problems: Switching loop; Bad cables/
improper cable types; Port configuration; VLAN assignment; Mismatched MTU/MTU black hole;
Power failure; Bad/missing routes; Bad modules (SFPs, GBICs); Wrong subnet mask; Wrong gateway;
Duplicate IP address; Wrong DNS
Given a set of requirements, plan and implement a basic SOHO network: List of requirements;
Cable length; Device types/requirements; Environment limitations; Equipment limitations; Compatibility requirements
1, 3, 6, 7
6
7
8
4, 6, 8, 9, 12
9
13
12
7
5
9
13
13
3, 4
exam Objectives The exam objectives listed here are current as of this book’s publication date. Exam objectives
are subject to change at any time without prior notice and at CompTIA’s sole discretion. Please visit the CompTIA
Certifications webpage for the most current listing of exam objectives: http://certification.comptia.org/getCertified/
certifications.aspx.
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Objective
chapter
3.0
3.1
2
3.2
3.3
3.4
3.5
3.6
3.7
3.8
4.0
4.1
4.2
4.3
4.4
4.5
4.6
5.0
5.1
5.2
5.3
5.4
5.5
5.6
NetwOrk meDia aND tOpOLOGies (17 perceNt)
Categorize standard media types and associated properties: Fiber (Multimode, Singlemode); Copper (UTP, STP, CAT3, CAT5, CAT5e, CAT6, CAT6a, Coaxial, Crossover, T1 Crossover, Straight-through);
Plenum vs. non-plenum; Media converters (Singlemode fiber to Ethernet, Multimode fiber to Ethernet, Fiber to Coaxial, Singlemode to multimode fiber); Distance limitations and speed limitations;
Broadband over powerline
Categorize standard connector types based on network media: Fiber (ST, SC, LC, MTRJ); Copper
(RJ-45, RJ-11, BNC, F-connector, DB-9 [RS-232], Patch panel, 110 block [T568A, T568B])
Compare and contrast different wireless standards: 802.11 a/b/g/n standards (Distance, Speed,
Latency, Frequency, Channels, MIMO, Channel bonding)
Categorize WAN technology types and properties: Types (T1/E1, T3/E3, DS3, OCx, SONET, SDH,
DWDM, Satellite, ISDN, Cable, DSL, Cellular, WiMAX, LTE, HSPA+, Fiber, Dialup, PON, Frame relay,
ATMs); Properties (Circuit switch, Packet switch, Speed, Transmission media, Distance)
Describe different network topologies: MPLS; Point to point; Point to multipoint; Ring; Star; Mesh;
Bus; Peer-to-peer; Client-server; Hybrid
Given a scenario, troubleshoot common physical connectivity problems: Cable problems (Bad
connectors; Bad wiring; Open; short; Split cables; DB loss; TXRX reversed; Cable placement; EMI/
Interference; Distance; Cross-talk)
Compare and contrast different LAN technologies: Types (Ethernet, 10BaseT, 100BaseT, 1000BaseT,
100BaseTX, 100BaseFX, 1000BaseX, 10GBaseSR, 10GBaseLR, 10GBaseER, 10GBaseSW, 10GBaseLW,
10GBaseEW, 10GBaseT); Properties (CSMA/CD, CSMA/CA, Broadcast, Collision, Bonding, Speed,
Distance)
Identify components of wiring distribution: IDF, MDF, Demarc, Demarc extension, Smart jack, CSU/
DSU
NetwOrk maNaGemeNt (20 perceNt)
Explain the purpose and features of various network appliances: Load balancer; Proxy server; Content filter; VPN concentrator
Given a scenario, use appropriate hardware tools to troubleshoot connectivity issues: Cable tester;
Cable certifier; Crimper; Butt set; Toner probe; Punch down tool; Protocol analyzer; Loop back plug;
TDR; OTDR; Multimeter; Environmental monitor
Given a scenario, use appropriate software tools to troubleshoot connectivity issues: Protocol analyzer; Throughput testers; Connectivity software; Ping; Tracert/traceroute; Dig; Ipconfig/ifconfig;
Nslookup; Arp; Nbtstat; Netstat; Route
Given a scenario, use the appropriate network monitoring resource to analyze traffic: SNMP;
SNMPv2; SNMPv3; Syslog; System logs; History logs; General logs; Traffic analysis; Network sniffer
Describe the purpose of configuration management documentation: Wire schemes; Network maps;
Documentation; Cable management; Asset management; Baselines; Change management
Explain different methods and rationales for network performance optimization: Methods (QoS,
Traffic shaping, Load balancing, High availability, Caching engines, Fault tolerance, CARP); Reasons
(Latency sensitivity, High bandwidth applications [VoIP, video applications, unified communications], Uptime)
NetwOrk secUritY (19 perceNt)
Given a scenario, implement appropriate wireless security measures: Encryption protocols (WEP,
WPA, WPA2, WPA Enterprise); MAC address filtering; Device placement; Signal strength
Explain the methods of network access security: ACL (MAC filtering, IP filtering, Port filtering);
Tunneling and encryption (SSL VPN, VPN, L2TP, PPTP, IPSec, ISAKMP, TLS, TLS2.0, Site-to-site and
client-to-site); Remote access (RAS, RDP, PPPoE, PPP, ICA, SSH)
Explain methods of user authentication: PKI; Kerberos; AAA (RADIUS, TACACS+); Network access
control (802.1x, posture assessment); CHAP; MS-CHAP; EAP; Two-factor authentication; Multifactor
authentication; Single sign-on
Explain common threats, vulnerabilities, and mitigation techniques: Wireless (War driving, War
chalking, WEP cracking, WPA cracking, Evil twin, Rogue access point); Attacks (DoS, DDoS, Man in
the middle, Social engineering, Virus, Worms, Buffer overflow, Packet sniffing, FTP bounce, Smurf);
Mitigation techniques (Training and awareness, Patch management, Policies and procedures,
Incident response)
Given a scenario, install and configure a basic firewall: Types (Software and hardware firewalls); Port
security; Stateful inspection vs. packet filtering; Firewall rules (Block/allow, Implicit deny, ACL); NAT/
PAT; DMZ
Categorize different types of network security appliances and methods: IDS and IPS (Behavior
based, Signature based, Network based, Host based); Vulnerability scanners (NESSUS, NMAP);
Methods (Honeypots, Honeynets)
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4
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2
13
12
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11
4, 10, 11
11
11
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11
CompTIA Network+
Exam N10-005
Training Kit
Craig Zacker
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Published with the authorization of Microsoft Corporation by:
O’Reilly Media, Inc.
1005 Gravenstein Highway North
Sebastopol, California 95472
Copyright © 2012 by Craig Zacker
All rights reserved. No part of the contents of this book may be reproduced
or transmitted in any form or by any means without the written permission of
the publisher.
ISBN: 978-0-7356-6275-9
1 2 3 4 5 6 7 8 9 QG 7 6 5 4 3 2
Printed and bound in the United States of America.
Microsoft Press books are available through booksellers and distributors
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Book Support at mspinput@microsoft.com. Please tell us what you think of
this book at http://www.microsoft.com/learning/booksurvey.
Microsoft and the trademarks listed at http://www.microsoft.com/about/legal/
en/us/IntellectualProperty/Trademarks/EN-US.aspx are trademarks of the
Microsoft group of companies. All other marks are property of their respective owners.
The example companies, organizations, products, domain names, email addresses, logos, people, places, and events depicted herein are fictitious. No
association with any real company, organization, product, domain name,
email address, logo, person, place, or event is intended or should be inferred.
This book expresses the author’s views and opinions. The information contained in this book is provided without any express, statutory, or implied
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nor its resellers, or distributors will be held liable for any damages caused or
alleged to be caused either directly or indirectly by this book.
acquisitions and Developmental editors: Ken Jones, Kenyon Brown
production editor: Holly Bauer
editorial production: Online Training Solutions, Inc.
technical reviewers: Dan Tuuri, Brian Blum
copyeditor: Kathy Krause, Online Training Solutions, Inc.
indexer: Angela Howard
cover Design: Twist Creative • Seattle
cover composition: Karen Montgomery
illustrator: Rebecca Demarest
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Contents at a Glance
Introduction
xix
ChApTEr 1
Networking Basics
1
ChApTEr 2
The physical Layer
43
ChApTEr 3
Network Devices
101
ChApTEr 4
The Data-Link Layer
141
ChApTEr 5
Wireless Networking
191
ChApTEr 6
The Network Layer
229
ChApTEr 7
routing and Switching
291
ChApTEr 8
The Transport Layer
339
ChApTEr 9
The Application Layer
369
ChApTEr 10
Wide Area Networking
445
ChApTEr 11
Network Security
483
ChApTEr 12
Network Management
541
ChApTEr 13
Network Troubleshooting
583
Glossary
637
Index
655
About the Author
681
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Contents
introduction
chapter 1
xix
System Requirements
xix
Using the Companion CD
xx
Support & Feedback
xxi
Preparing for the Exam
xxii
Networking basics
1
Network Communications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
LANs and WANs
3
Signals and Protocols
5
Packet Switching and Circuit Switching
8
Client/Server and Peer-to-Peer Networks
9
The OSI Reference Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Protocol Interaction
12
Data Encapsulation
13
The Physical Layer
16
The Data-Link Layer
18
The Network Layer
22
The Transport Layer
25
The Session Layer
29
The Presentation Layer
31
The Application Layer
32
What do you think of this book? We want to hear from you!
Microsoft is interested in hearing your feedback so we can continually improve our
books and learning resources for you. To participate in a brief online survey, please visit:
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vii
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The TCP/IP Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
The Link Layer
35
The Internet Layer
36
The Transport Layer
36
The Application Layer
37
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
chapter 2
Exercise
40
Chapter Review
40
the physical Layer
43
Cables and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Copper Cable Types
46
Fiber Optic Cable
55
Power Line Networking
57
Media Converters
58
Topologies and Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Cable Topologies
59
Multiprotocol Label Switching
67
Cabling Standards
68
Installing Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Installing External Cables
70
Installing Internal Cables
73
Connecting to the Backbone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
viii
Exercise
99
Chapter Review
99
contents
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chapter 3
Network Devices
101
Network Interface Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Network Interface Adapter Functions
108
Optional Network Adapter Functions
109
Purchasing Network Interface Adapters
112
Installing a Network Interface Adapter
114
Troubleshooting a Network Interface Adapter
116
At the Other End of the Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Using Repeaters
117
Using Hubs
118
Using Bridges
122
Using Routers
124
Using Switches
129
Using Multifunction Devices
135
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
chapter 4
Exercise
139
Chapter Review
139
the Data-Link Layer
141
Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Ethernet Standards
143
Ethernet Components
145
Point-to-Point Protocol (PPP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
PPP Standards
170
The PPP Frame
171
Authentication Protocols
175
The IPCP Frame
176
PPP Connection Establishment
177
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ix
Address Resolution Protocol (ARP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
ARP Message Format
181
ARP Transactions
183
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
chapter 5
Exercise
189
Chapter Review
190
wireless Networking
191
Wireless LAN Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Building a Wireless Standard
193
IEEE 802.11 Standards
194
Wireless LAN Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
The Physical Layer
201
The Data-Link Layer
210
Installing a Wireless LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Examining the Site
215
Selecting Hardware
217
Installing and Configuring Wireless Hardware
222
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
chapter 6
Exercise
226
Chapter Review
226
the Network Layer
229
Internet Protocol (IP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
x
IP Standards
231
IP Versions
232
IP Functions
233
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IPv4 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
IPv4 Address Assignments
235
IPv4 Address Classes
236
IPv4 Address Types
237
Subnet Masking
238
Classless Inter-Domain Routing
243
Registered and Unregistered Addresses
245
Obtaining IP Addresses
247
Assigning IPv4 Addresses
248
IPv6 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
IPv6 Address Types
251
IPv6 Address Assignment
260
Data Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
The IPv4 Datagram Format
264
The IPv6 Datagram Format
268
IPv4 Fragmentation
271
IPv6 Fragmentation
272
IP Routing
273
Internet Control Message Protocol (ICMP) . . . . . . . . . . . . . . . . . . . . . . . . . 273
ICMPv4
273
ICMPv6
280
Internet Group Management Protocol (IGMP) . . . . . . . . . . . . . . . . . . . . . . 283
Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
Scenario #1
285
Scenario #2
285
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Exercises
288
Chapter Review
288
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xi
chapter 7
routing and switching
291
Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
What Is Routing?
293
Router Functions
294
Router Products
297
Understanding Routing Tables
298
Routing in IPv6
308
Routing and ICMP
308
Routing and Network Address Translation
309
Static and Dynamic Routing
313
Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
Routing vs. Switching
328
Configuring VLAN Trunking Protocol (VTP)
332
Power Over Ethernet (PoE)
333
Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Scenario #1
334
Scenario #2
334
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
chapter 8
Exercises
337
Chapter Review
337
the transport Layer
339
Transmission Control Protocol (TCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
The TCP Header
341
TCP Options
343
TCP Communications
345
User Datagram Protocol (UDP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
Ports and Sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
xii
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Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
chapter 9
Exercise
366
Chapter Review
366
the application Layer
369
Application Layer Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
DHCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
DHCP Origins
371
DHCP Objectives
372
IP Address Assignment
374
Creating Scopes
375
TCP/IP Client Configuration
375
DHCP Packet Structure
376
DHCP Options
378
DHCP Communications
380
Relay Agents
388
DHCPv6
389
DNS 395
Host Tables
395
DNS Objectives
396
Domain Naming
398
Resource Records
404
DNS Messaging
405
DNS Name Resolution
406
Reverse Name Resolution
412
DNS Name Registration
414
Zone Transfers
416
HTTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
HTTP Requests
418
HTTP Responses
419
HTTP Message Exchanges
420
HTTPS
422
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xiii
FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
FTP Commands
423
FTP Messaging
424
TFTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
Telnet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
Email . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
Email Addressing
428
Email Clients and Servers
428
SMTP
430
POP3
433
IMAP
435
NTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
Exercise
442
Chapter Review
442
chapter 10 wide area Networking
445
What Is a WAN? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .446
Connecting to the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .448
Public Switched Telephone Network
448
Integrated Services Digital Network (ISDN)
450
Digital Subscriber Line (DSL)
452
Cable Television (CATV) Networks
454
Satellite-Based Services
455
Last Mile Fiber
456
Cellular Technologies
457
Connecting LANs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
xiv
Leased Lines
460
SONET/SDH
463
Packet Switching
465
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Remote Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
Dial-up Remote Access
469
Virtual Private Networking
470
SSL VPN
475
Using a VPN Concentrator
475
Remote Terminal Emulation
475
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
Exercise
480
Chapter Review
480
chapter 11 Network security
483
Authentication and Authorization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
Network Authentication Systems
486
Authentication Protocols
493
Tunneling and Encryption Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
IPsec
501
SSL and TLS
507
Wireless Security Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
WEP
509
802.1X
511
WPA
512
Other Wireless Security Techniques
513
Firewalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
Packet Filtering
516
Stateful Packet Inspection
520
Firewall Implementations
521
Creating a Peripheral Network
525
Other Security Appliances
526
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xv
Security Threats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528
Denial of Service
529
Man in the Middle
529
Malware
530
Buffer Overflow
531
Social Engineering
531
Wireless Threats
532
Mitigation Techniques
533
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
Exercise
538
Chapter Review
538
chapter 12 Network management
541
Network Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
Cable Diagrams
543
Network Diagrams
544
Network Maps
546
Hardware Configurations
546
Change Management
547
Baselines
547
Network Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
Logs
xvi
549
SNMP
556
Protocol Analyzers
558
Port Scanners
563
Vulnerability Scanners
565
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Virtualization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
Virtualization Architectures
567
Desktop Virtualization
569
Virtual Switching
570
Presentation Virtualization
570
Application Virtualization
571
Virtual PBXes
571
Performance Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572
Caching Data
573
Traffic Control
574
Redundant Services
575
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
Exercise
581
Chapter Review
581
chapter 13 Network troubleshooting
583
Troubleshooting Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
The Ping Program
585
Traceroute
586
Ifconfig and Ipconfig.exe
588
ARP
589
Netstat
590
Nbtstat.exe
594
Nslookup
595
Dig
596
Route
597
What do you think of this book? We want to hear from you!
Microsoft is interested in hearing your feedback so we can continually improve our
books and learning resources for you. To participate in a brief online survey, please visit:
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contents
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xvii
Troubleshooting Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
Identify the Problem
598
Establish a Theory
601
Test the Theory
601
Establish a Plan of Action
602
Implement the Solution
603
Verify System Functionality
603
Document Findings
604
Troubleshooting Connectivity Issues
605
Troubleshooting Wireless Problems
606
Troubleshooting Router and Switch Problems
607
Network Troubleshooting Scenario: “I Can’t Access a Website” . . . . . . . . 612
Incident Administration
612
Gathering Information
613
Possible Cause: Internet Router Problem
614
Possible Cause: Internet Communication Problem
616
Possible Cause: DNS Failure
617
Possible Cause: LAN Communications Problem
622
Possible Cause: Computer Configuration Problem
626
Possible Cause: User Error
630
Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
Chapter Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634
xviii
Exercise
634
Chapter Review
634
Glossary
637
Index
655
contents
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Introduction
This training kit is designed for information technology (IT) professionals who support or plan
to support networks and who also plan to take the CompTIA Network+ exam. It is assumed
that before you begin using this kit, you have a CompTIA A+ certification or the equivalent
knowledge, as well as 9 to 12 months of work experience in IT networking.
The material covered in this training kit and on the Network+ exam relates to the technologies in a network that support distributed access to web content, media, operating systems,
and applications. The topics in this training kit cover what you need to know for the exam as
described on the Certification Exam Objectives document for the exam, which is available at:
http://certification.comptia.org/getCertified/certifications/network.aspx
By using this training kit, you will learn how to do the following:
■
Use the Open Systems Interconnection (OSI) reference model to understand network
processes.
■
Install and maintain the various cables and other media used to build networks.
■
Understand the protocols that networked computers use to communicate.
■
Understand how routers and switches connect network devices to each other and to
other networks.
■
Connect to distant networks by using wide area network (WAN) technologies.
■
Secure a network by using firewalls and other tools.
■
Use network monitoring and diagnostic tools.
■
Troubleshoot network problems in a systematic and logical manner.
Refer to the objective mapping page in the front of this book to see where in the book
each exam objective is covered.
system requirements
CompTIA suggests you have access to various hardware and software to help you prepare for
the Network+ exam. The items include equipment, spare hardware, spare parts, tools, software, and other items you might need. You’ll find a list of items at the back of the CompTIA
Network+ Certification Exam Objectives: N10-005 guide, which you can download from
the CompTIA website. Please visit http://certification.comptia.org/getCertified/certifications/
network.aspx for more information.
xix
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Using the companion cD
A companion CD is included with this training kit. The companion CD contains the following:
■
practice tests You can reinforce your understanding of the topics covered in this
training kit by using electronic practice tests that you customize to meet your needs.
You can practice for the Network+ certification exam by using tests created from a
pool of 200 realistic exam questions, which give you many practice exams to ensure
that you are prepared.
■
an ebook An electronic version (eBook) of this book is included for when you do not
want to carry the printed book with you.
Note
cOmpaNiON cONteNt FOr DiGitaL bOOk reaDers
If you bought a digital-only edition of this book, you can enjoy select content from the
print edition’s companion CD. Visit http://go.microsoft.com/FWLink/?Linkid=248373 to get
your downloadable content.
how to Install the practice Tests
To install the practice test software from the companion CD to your hard disk, perform the
following steps:
1.
Insert the companion CD into your CD drive and accept the license agreement. A CD
menu appears.
Note
iF the cD meNU DOes NOt appear
If the CD menu or the license agreement does not appear, Autorun might be disabled
on your computer. Refer to the Readme.txt file on the CD for alternate installation
instructions.
2.
Click Practice Tests and follow the instructions on the screen.
xx introduction
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how to Use the practice Tests
To start the practice test software, follow these steps:
1.
Click Start, All Programs, and then select Microsoft Press Training Kit Exam Prep.
2.
A window appears that shows all the Microsoft Press training kit exam prep suites
installed on your computer.
3.
Double-click the practice test you want to use.
When you start a practice test, you choose whether to take the test in Certification Mode,
Study Mode, or Custom Mode:
■
Certification Mode Closely resembles the experience of taking a certification exam.
The test has a set number of questions. It is timed, and you cannot pause and restart
the timer.
■
study mode Creates an untimed test during which you can review the correct answers and the explanations after you answer each question.
■
custom mode Gives you full control over the test options so that you can customize
them as you like.
In all modes, the user interface when you are taking the test is basically the same but with
different options enabled or disabled depending on the mode.
When you review your answer to an individual practice test question, a “References” section is provided that lists where in the training kit you can find the information that relates to
that question. After you click Test Results to score your entire practice test, you can click the
Learning Plan tab to see a list of references for every objective.
how to Uninstall the practice Tests
To uninstall the practice test software for a training kit, use the Programs And Features option
in Control Panel.
support & Feedback
The following sections provide information on errata, book support, feedback, and contact
information.
introduction xxi
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Errata & Book Support
We’ve made every effort to ensure the accuracy of this book and its companion content. Any
errors that have been reported since this book was published are listed on our Microsoft Press
site at oreilly.com:
http://go.microsoft.com/FWLink/?Linkid=248372
If you find an error that is not already listed, you can report it to us through the
same page.
If you need additional support, email Microsoft Press Book Support at:
mspinput@microsoft.com
Please note that product support for Microsoft software is not offered through the
addresses above.
We Want to hear from You
At Microsoft Press, your satisfaction is our top priority, and your feedback is our most
valuable asset. Please tell us what you think of this book at:
http://www.microsoft.com/learning/booksurvey
The survey is short, and we read every one of your comments and ideas. Thanks in
advance for your input!
Stay in Touch
Let’s keep the conversation going! We are on Twitter: http://twitter.com/MicrosoftPress.
preparing for the exam
CompTIA certification exams are a great way to build your resume and let the world know
about your level of expertise. Certification exams validate your on-the-job experience and
product knowledge. Although there is no substitute for on-the-job experience, preparation
through study and hands-on practice can help you prepare for the exam. We recommend
that you augment your exam preparation plan by using a combination of available study
materials and courses. For example, you might use the Training Kit and another study guide
for your “at home” preparation, and take a CompTIA professional certification course for the
classroom experience. Choose the combination that you think works best for you.
xxii introduction
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chapter 1
Networking Basics
T
his chapter introduces the fundamental computer networking concepts that form the basis for all of the questions on
the CompTIA Network+ examination. You might be inclined to
skip around in this book during your exam preparation regimen,
but you should make sure that you understand the principles in
this chapter before you do so. Otherwise, you might find yourself struggling later, both in the exam room and on the job.
imp ortant
Have you read
page xxii?
It contains valuable
information regarding
the skills you need to
pass the exam.
Exam objectives in this chapter:
Objective 1.1: Compare the layers of the OSI and TCP/IP models.
■
OSI model:
■
TCP/IP model:
●
Layer 1 – Physical
●
Network Interface Layer
●
Layer 2 – Data link
●
Internet Layer
●
Layer 3 – Network
●
Transport Layer
●
Layer 4 – Transport
●
Application Layer
●
Layer 5 – Session
●
Layer 6 – Presentation
●
Layer 7 – Application
❍
(Also described as: Link Layer,
Internet Layer, Transport Layer,
Application Layer)
Objective 1.2: Classify how applications, devices, and protocols relate to the OSI model layers.
■
MAC address
■
Multilayer switch
■
IP address
■
Hub
■
EUI-64
■
Encryption devices
■
Frames
■
Cable
■
Packets
■
NIC
■
Switch
■
Bridge
■
Router
1
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ReAL WoRLD
reiNveNtiNG NetwOrk+
Anyone familiar with the earlier incarnations of the CompTIA Network+ examination might
notice that there are some rather profound differences between the objectives tested by
the N10-004 version of 2009 and those in the N10-005 version released in late 2011. Some
of these changes are representative of the latest developments in networking technology,
and others demonstrate a definite change in the focus of the exam.
First, and most obvious, is the elimination of many technologies that have lapsed into
obsolescence. With Ethernet now unquestionably the dominant data-link layer protocol
on the desktop, older protocols such as Token ring and Fiber Distributed Data Interface
(FDDI), which were included in the 2005 edition of the objectives, are now gone. Conversely,
the 802.11 wireless LAN standards that barely rated a mention in 2005 and received two
objectives in 2009 now have four, making them a major part of the exam.
At the network and transport layers, TCp/Ip is now ubiquitous, displacing older alternatives
such as IpX/SpX, NetBEUI, and AppleTalk. This is not to say that you will never encounter
any of these protocols in the field ever again, but they are now considered rare, if not actually endangered, species.
Whereas the 2005 objectives specified the need for basic knowledge of various server
operating systems, the 2009 and 2011 objectives place far more concentration on specific
areas of network support, such as configuration management, performance optimization,
and troubleshooting methodologies. The operating system names no longer appear in the
objectives at all.
The 2011 objectives also clarify the examination’s emphasis on infrastructure management.
New objectives single out services such as DNS and DhCp for particular concentration and
deemphasize hardware and software technologies that are fading from general use.
Network communications
What is a data network? Simply put, a data network is an array of computers and other devices
connected together by a common medium that enables them to communicate with each
other. That common medium can be wired, using copper or fiber optic cables; wireless, using
infrared or radio signals; or connected to a service provider, such as a telephone or cable television network. A data network can be as simple as two home computers connected together,
or as complex as the Internet, joining millions of computers together around the world.
Why connect computers together? The two primary reasons to create data networks are to:
2
■
Share hardware
■
Share data
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In the early days of the PC, the only way to print a document was to connect a printer
directly to a computer. As more and more companies adopted the PC as a business tool, it
became impractical to buy a printer for every computer or to move a single printer from
computer to computer as needed. By connecting computers to a network, they could share a
single printer.
Key
In the same way, networking made it possible for computers to share data. Rather
than save a document file to a removable disk and walk it to another computer—a process
colloquially known as the sneakernet—users could store files on a common server, enabling
anyone to access them. As networks grew larger and more complex, so did the applications
that made use of them. Today, in addition to document files and printer jobs, networks carry
data in the form of email messages, webpages, video streams, and many other types.
LANs and WANs
Key
The earliest PC networks used copper-based cables as the network medium, and many still
do. A local area network (LAN) is a group of computers or other devices that share a common
location, such as a room, a floor, or a building; and a common network medium, such as a
particular type of cable. The medium interconnects the computers so that they are capable of
sharing data with each other. LANs can include network connection devices, such as switches
and routers, and are also characterized by their relatively high data transmission rates and
their ability to function without the need for outside service providers.
A typical small LAN is shown in Figure 1-1. LANs are wholly owned by an organization and
require no licensing or registration. Anyone can purchase the hardware required and assemble a LAN in his or her home or office.
FiGUre 1-1 A typical small LAN.
Key
Devices connected to a LAN, such as computers or printers, are generically referred to as
nodes. A 50-node network is therefore a single network medium with 50 computers or other
devices connected to it.
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chapter 1
3
exAm tip
Virtually all of the wired LANs installed today use a technology known as Ethernet or, more
precisely, IEEE 802.3. There are several other antiquated LAN technologies, including Token
ring and FDDI, that are no longer covered by the Network+ exam, and for which products
are no longer available on the market, but that you might conceivably encounter in older
installations.
Key
LANs are expandable within certain limits imposed by the protocols they use to communicate, but in large installations, it is often necessary to connect multiple LANs together. To
do this, you use a device called a router, as shown in Figure 1-2. A router is simply a device
that connects networks together, forming what is known as a “network of networks” or, more
commonly, an “internetwork.”
Router
FiGUre 1-2 Two LANs connected by a router.
Note
internet or internet?
Do not confuse the terms “internetwork” or “internet” (with a lowercase “i”) with the Internet (with a capital “I”). The term “Internet” describes a specific example of that for which
“internetwork” is the generic designation. In other words, the Internet is a specific type of
internetwork, but not every use of the term “internetwork” refers to the Internet.
Key
4
A wide area network (WAN) is a group of computers connected by a longer distance
communication technology provided by a third-party service provider, such as a telephone
company. Internet connections for LANs or individual computers, whether they use dial-up
modems and telephone lines or broadband technologies, are all WAN links. Corporate networks also use WAN technologies to connect offices at remote sites together. Most WAN connections are point-to-point links joining two sites together; a company with multiple branch
offices in different cities might have separate WAN links connecting each branch to the main
office. As with LANs, WANs are connected together by routers, as shown in Figure 1-3.
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Router
Router
WAN Link
FiGUre 1-3 Two LANs connected by a WAN link.
moRe iNfo
waN techNOLOGies
For more information on the various types of WAN technologies currently in use, see
Chapter 10, “Wide Area Networking.”
WAN connections can take many forms and use many different communications technologies. Subscribers, whether private individuals or large companies, can choose from among
a variety of WAN providers offering connections with different speeds and services. Generally speaking, WAN connections are much slower than LAN connections and are far more
expensive. Most LANs today run at 100 or 1,000 megabits per second (Mbps), and the only
costs involved are for the required hardware components. WAN connections typically run at
speeds of up to 4 Mbps for residential Internet connections, and up to 25 Mbps for business
connections. Very few even approach the speed of a modest LAN. Subscription prices vary
depending on the speed of the connection and the other services provided.
Signals and protocols
All of the computers connected to a network communicate by exchanging signals with each
other. The nature of the signals depends on the network medium. The three most common
types of signals used for network communications are as follows:
■
electrical Networks that use copper-based cables as a medium communicate by using electrical signals, voltages generated by the transceiver in each node.
■
Light Fiber optic cables carry signals in the form of pulses of light, and some wireless
networks use infrared light as a signaling medium.
■
radio Most wireless networks communicate by using radio signals.
In each of these cases, the signals form a simple code that enables the computers to
transmit data over the network. At the signaling level, network communications are extremely
simple, consisting only of positive or negative voltages, the presence or absence of light, or
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chapter 1
5
specific radio frequency variations. The process by which complex data structures, such as
print jobs, email messages, and video streams, get reduced to simple signals is the responsibility of software components called protocols, which run on each computer.
Protocols are essentially languages that operate at various levels of the networking software on each computer or other device. Just as two people must speak the same language
to be able to talk to each other, two computers on the same network must use the same
protocols to communicate. Unlike human speech, however, which uses a single language, a
networked computer uses multiple protocols in layers, forming a construction known as a
protocol stack.
Key
The signals that the computer transmits over the network medium are at the bottom of
the stack, and the applications that handle the data are at the top, as shown in Figure 1-4.
One of the primary functions of the protocol stack is to reduce the data generated by the
applications running on the computer down to the simple signals suitable for the network
medium. When the signals arrive at their destination, the protocol stack performs the same
process in reverse, interpreting the incoming signals and restoring them to their original form.
Application
Protoco