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Chapter 5 LANs and WLANs

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.

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Chapter 5 LANs and WLANs






Presentation on theme: "Chapter 5 LANs and WLANs"— Presentation transcript:

Slide1

Chapter 5

LANs and WLANsSlide2

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 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.

Chapter 5: LANs and WLANs

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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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Chapter 5: LANs and WLANs

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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.

Chapter 5: LANs and WLANs30Slide31

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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

60Slide61

Chapter 5 Complete

LANs and WLANs