Chapter 5 LANs and WLANs 2 Chapter Contents Section A Network Building Blocks Section B Wired Networks Section C Wireless Networks Section D Using LANs Section E Security Through Encryption ID: 656846
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Chapter 5
LANs and WLANsSlide2
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Chapter Contents
Section A: Network Building Blocks
Section B: Wired Networks
Section C: Wireless Networks
Section D: Using LANs
Section E: Security Through EncryptionSlide3
FastPoll True/False QuestionsAnswer A for True and B for False
050100
In a network, a server is a computer that provides services to other computers called peers.
050200
Star, ring, and mesh are examples of network topologies.
050300
When you send an e-mail message over a network, it is chopped up into packets.
050400 The IP address assigned to your computer on the Internet is derived from your computer’s MAC address. 050500 Some network technologies use home telephone or electric cabling for computer networks.
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FastPoll True/False QuestionsAnswer A for True and B for False
050600
The most popular type of wired network is Ethernet.
050700
Network speeds are measured in megabytes and gigabytes.
050800
Many wireless networks use radio waves to transmit data.
050900 Bluetooth is a wireless technology used for WANs.Chapter 5: LANs and WLANs4Slide5
FastPoll True/False QuestionsAnswer A for True and B for False
051000
A wireless infrastructure network
uses a centralized broadcasting device, such as a wireless access point or router.
051100
Wireless networks are less secure than wired networks.
051200 WEP, WPA, and PSK are examples of Wi-Fi networks. 051300 Public key encryption uses a public key to encrypt messages, but a private key is required to decrypt messages.
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Network Building Blocks
Network Classifications
LAN Standards
Network Devices
Clients, Servers, and Peers
Physical TopologyNetwork LinksCommunications ProtocolsSlide7
Question
052100
Networks come in many sizes and use many different technologies, yet they all need to communicate with each other. What is the key to network intercommunication?
A. Packet switching
B. Network protocols
C. Network topology
D. Peer-to-peer technology
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Network Classifications
Personal Area Network (PAN) – interconnection of personal digital devices
Local Area Network (LAN) – usually connects computers in a single building
Metropolitan Area Network (MAN) – public high-speed network with range of about 50 miles
Wide Area Network (WAN) – consists of several smaller networksSlide9
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LAN Standards
LAN technologies are standardized by the Institute of Electrical and Electronics Engineers (IEEE)
Project 802 – Local Network Standards
IEEE 802.3
ARCnet
Token RingFDDIEthernetSlide10
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Network Devices
Each connection point on a network is referred to as a node
To connect to a LAN, a computer requires network circuitry, sometimes referred to as a network interface card (NIC)
A networked peripheral, or network-enabled peripheral, is any device that contains network circuitry to directly connect to a network
A network device, or network appliance, is any electronic device that broadcasts network data, boosts signals, or routes data to its destinationSlide11
Network Devices
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Clients, Servers, and Peers
Network devices can function as clients or as servers
Application server
File server
Print server
Networks that include one or more servers can operate in client/server modeSlide13
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Physical Topology
The arrangement of devices in a network is referred to as its physical topology
Star
Ring
Bus
Mesh
TreeTwo similar networks can
be connected by a device
called a bridge
Gateway is a generic term
for any device or software
code used to join two networksSlide14
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Network Links
A communications channel, or link, is a physical path or frequency for signal transmissions
Bandwidth is the transmission capacity of a communications channel
Broadband
NarrowbandSlide15
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Communications Protocols
Rules for efficiently transmitting data from one network node to another:
Divide messages into packets
Affix addresses to packets
Initiate transmission
Regulate flow of dataCheck for transmission errorsAcknowledge receipt of transmitted dataSlide16
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Communications Protocols
A packet is a “parcel” of data that is sent across a computer network
Circuit-switching technology vs. packet switching technologySlide17
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Communications Protocols
Every packet that travels over a network includes the address of its destination device
A MAC address is a unique number assigned to a network interface card when it is manufactured
An IP address is a series of numbers used to identify a network device
IP addresses can also be obtained through DHCPSlide18
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Wired Networks
Wired Network Basics
HomePNA and Powerline Networks
Ethernet
Ethernet Equipment
Ethernet SetupSlide19
Question
052200
Suppose you’re setting up a network in your home or apartment. You want all of the computers to access the cable modem that provides Internet access. What is the one additional component that you should purchase to tie the network together?
A. A router
B. A network interface card
C. A file server
D. A
HomePlug Ethernet portChapter 5: LANs and WLANs
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Wired Network Basics
A wired network uses cables to connect network devices
Wired networks are fast, secure, and simple to configure
Devices tethered to cables
have limited mobilitySlide21
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HomePNA and
Powerline Networks
HomePNA networks utilize existing telephone wiring or coaxial cables to connect network devices
Special NICs and cables are required
A powerline network uses premises electrical wiring to form the infrastructure for a LANSlide22
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Ethernet
Simultaneously broadcasts data packets to all network devices
IEEE 802.3
CSMA/CD protocol
Vary in speed from 10Mbps to 100GbpsSlide23
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Ethernet
On an Ethernet, data travels on a first-come, first-served basis. If two workstations attempt to send data at the same time, a collision occurs.
That data must be resent.Slide24
Ethernet Equipment
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Ethernet Equipment
Ethernet adapter (designed to support the Ethernet protocols)
Network hub
Network switch
Network router
RJ45 connectorSlide26
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Ethernet SetupSlide27
Ethernet Setup
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Ethernet Setup
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Most routers are configured using a browser. You should
change the network administrator password, then verify that DHCP is enabledSlide29
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Wireless Networks
Wireless Basics
Bluetooth
Wi-Fi
Wi-Fi Equipment
Wi-Fi SetupSlide30
Question
052300
When you’re setting up a wireless network, you see an option asking if you want to broadcast the network SSID. You should:
A. Change the default SSID and broadcast it while you set up the network.
B. Turn SSID broadcasting off so that hackers don’t know the network’s encryption key.
C. Make sure SSID is broadcasting so that your network is protected by strong encryption.
D. Activate SSID broadcasting or else the network devices won’t be able to send data to the router.
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Wireless Basics
A wireless network transports data from one device to another without cables or wires
RF signals
Transceiver
Microwaves
Infrared lightSlower than wired networksSecurity concernsSlide32
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Bluetooth
Bluetooth is a short-range, wireless network technology designed to make its own connections between electronic devices, without wires, cables, or any direct action from a userSlide33
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Wi-Fi
Wireless networking technologies that are compatible with Ethernet
MIMO technology uses two or more antennas to send multiple sets of signalsSlide34
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Wi-Fi EquipmentSlide35
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Wi-Fi Equipment
If your computer is not pre-equipped with wireless circuitry, you can purchase and install a Wi-Fi adapterSlide36
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Wi-Fi Equipment
Wireless network setups
Wireless ad-hoc network
Wireless infrastructure network
Wireless
access pointWireless routerSlide37
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Wi-Fi Setup
Set up the router
Connect to the router with a computer
Configure the router
Access the router setup utility
Create a new router passwordSlide38
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Wi-Fi Setup
Enter an SSID for the network
Activate WEP, WPA, or PSK and create an encryption key
Set up the wireless workstations
Connect an Internet access deviceSlide39
Wi-Fi Setup
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Using LANs
LAN Advantages and Challenges
Sharing Files
Sharing Printers
LAN Parties
TroubleshootingSlide41
Question
052400
There are many ways to share files among the computers on a network. Which one of the following is the LEAST secure way to share files?
A. Use a file server.
B. Activate file sharing for the root directory of all the computers in the network.
C. Designate specific folders on your computer as shared.
D. Put files you want to share in the Public folder.
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LAN Advantages
and Challenges
LANs enable people to work together
Sharing networked software can reduce costs
Sharing data on a LAN can increase productivity
Sharing networked hardware can reduce costsSharing networked hardware can provide access to a wide range of services and specialized peripheral devicesSlide43
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LAN Advantages
and Challenges
Resources become unavailable when network malfunctions
Networks may be vulnerable to unauthorized access
More vulnerable than standalone computers
Wireless networks can be tapped from a “snooping” computerNetworked computers are susceptible to an increasing number of worms, Trojan horses, and blended threatsSlide44
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Sharing Files
If you use Windows, it automatically detects available LANs any time you turn on a workstation
To connect to a shared resource, you might be asked for a user ID and passwordSlide45
Sharing Files
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Sharing Files
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Sharing Printers
Three setups allow for printer sharing:
Set up printer sharing using a workstation printer
Set up printer sharing using a print server
Install printer with built-in networkingSlide48
Sharing Printers
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You can designate the printer attached to your computer as
sharable over the network.Slide49
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LAN Parties
A LAN party is a gathering of people who connect their own computers to a LAN, usually to play multiplayer computer games
No special hardware usually is required
Game must have multiplayer capabilitySlide50
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Troubleshooting
Network problems can stem from a variety of sources
Cables
Signal strength
Security
InterferenceNetwork devicesSettingsSlide51
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Security Through Encryption
Wi-Fi Security
EncryptionSlide52
Question
052500
As part of the process of setting up a wired network, what should you remember to do?
A. Assign an IP address to each network device.
B. Remove the Ethernet card from any computer that has one.C. Enable wireless security.
D. Disable the SSID.
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Wi-Fi Security
Wireless networks are much more susceptible to unauthorized access and use than wired networks
LAN jacking, or war driving, is the practice of intercepting wireless signals by cruising through an areaSlide54
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Wi-Fi Security
Wireless encryption scrambles data transmitted between wireless devices and then unscrambles the data only on devices that have a valid encryption key
WEP (Wired Equivalent Privacy)
WPA (Wi-Fi Protected Access)
WPA2
PSKActivate encryption by using a wireless network keySlide55
Wi-Fi Security
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Encryption
Encryption transforms a message so that its contents are hidden from unauthorized readers
Plaintext has not yet been encrypted
An encrypted message is referred to as ciphertext
Decryption is the opposite of encryption
Cryptographic algorithmCryptographic keySlide57
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Encryption
Weak vs. strong encryption
AES (Advanced Encryption Standard)
Encryption methods can be broken by the use of expensive, specialized, code-breaking computers
Brute-force methodSlide58
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Encryption
Public key encryption (PKE) eliminates key-distribution problem, by using one key to encrypt a message and another key to decrypt the messageSlide59
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Encryption
When personal computer users want to encrypt e-mail or other documents, they turn to public key encryption software called PGP (Pretty Good Privacy) softwareSlide60
What Do You Think?
053100
Have you ever accessed a free WLAN?
A. Yes B. No C. Not sure
053200
Do you believe that rogue WLANs can survive alongside for-profit broadband ISPs?
A. Yes B. No C. Not sure
053300 Are broadband providers justified in limiting the terms of their service agreements to “one subscription, one customer”?A. Yes B. No C. Not sureChapter 5: LANs and WLANs
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Chapter 5 Complete
LANs and WLANs