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Chapter 5 LANs and WLANs
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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 Encryption Chapter 5: LANs and WLANs
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FastPoll True/False Questions Answer A for True and B for False
In a network, a server is a computer that provides services to other computers called peers. Star, ring, and mesh are examples of network topologies. When you send an message over a network, it is chopped up into packets. The IP address assigned to your computer on the Internet is derived from your computer’s MAC address. Some network technologies use home telephone or electric cabling for computer networks. Chapter 5: LANs and WLANs
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FastPoll True/False Questions Answer A for True and B for False
The most popular type of wired network is Ethernet. Network speeds are measured in megabytes and gigabytes. Many wireless networks use radio waves to transmit data. Bluetooth is a wireless technology used for WANs. Chapter 5: LANs and WLANs
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FastPoll True/False Questions Answer A for True and B for False
A wireless infrastructure network uses a centralized broadcasting device, such as a wireless access point or router. Wireless networks are less secure than wired networks. WEP, WPA, and PSK are examples of Wi-Fi networks. Public key encryption uses a public key to encrypt messages, but a private key is required to decrypt messages. Chapter 5: LANs and WLANs
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Network Building Blocks
Network Classifications LAN Standards Network Devices Clients, Servers, and Peers Physical Topology Network Links Communications Protocols Chapter 5: LANs and WLANs
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Question 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 Chapter 5: LANs and WLANs
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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 networks Chapter 5: LANs and WLANs
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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 Ring FDDI Ethernet Chapter 5: LANs and WLANs
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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 destination Chapter 5: LANs and WLANs
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Network Devices Figure 5-3 Chapter 5: LANs and WLANs
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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 mode Figure 5-4 and 5-5 Chapter 5: LANs and WLANs
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Physical Topology The arrangement of devices in a network is referred to as its physical topology Star Ring Bus Mesh Tree Two 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 networks Figure 5-6 Chapter 5: LANs and WLANs
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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 Narrowband Figure 5-7 Chapter 5: LANs and WLANs
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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 data Check for transmission errors Acknowledge receipt of transmitted data Chapter 5: LANs and WLANs
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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 technology Figure 5-11 Chapter 5: LANs and WLANs
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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 DHCP Chapter 5: LANs and WLANs
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Wired Networks Wired Network Basics HomePNA and Powerline Networks
Ethernet Ethernet Equipment Ethernet Setup Chapter 5: LANs and WLANs
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Question 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 port Chapter 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 mobility Figure 5-12 Chapter 5: LANs and WLANs
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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 LAN Figures 5-13 and 5-14 Chapter 5: LANs and WLANs
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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 100Gbps Figure 5-15 Chapter 5: LANs and WLANs
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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. Figure 5-16 Chapter 5: LANs and WLANs
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Ethernet Equipment Figure 5-18 Chapter 5: LANs and WLANs
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Ethernet Equipment Ethernet adapter (designed to support the Ethernet protocols) Network hub Network switch Network router RJ45 connector Figures 5-19 and 5-20 and 5-21 Chapter 5: LANs and WLANs
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Ethernet Setup Chapter 5: LANs and WLANs
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Ethernet Setup Figure 5-23 Chapter 5: LANs and WLANs
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Ethernet Setup Most routers are configured using a browser. You should
change the network administrator password, then verify that DHCP is enabled Figure 5-24 Chapter 5: LANs and WLANs
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Wireless Networks Wireless Basics Bluetooth Wi-Fi Wi-Fi Equipment
Wi-Fi Setup Chapter 5: LANs and WLANs
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Question 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 WLANs
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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 light Slower than wired networks Security concerns Figure 5-25 Chapter 5: LANs and WLANs
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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 user Figures 5-27 and 5-28 Chapter 5: LANs and WLANs
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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 signals Figure 5-29 Chapter 5: LANs and WLANs
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Wi-Fi Equipment Figure 5-31 Chapter 5: LANs and WLANs
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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 adapter Figure 5-33 Chapter 5: LANs and WLANs
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Wi-Fi Equipment Wireless network setups Wireless ad-hoc network
Wireless infrastructure network Wireless access point Wireless router Figure 5-34 Chapter 5: LANs and WLANs
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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 password Chapter 5: LANs and WLANs
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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 device Chapter 5: LANs and WLANs
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Wi-Fi Setup Figure 5-35 Chapter 5: LANs and WLANs
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Using LANs LAN Advantages and Challenges Sharing Files
Sharing Printers LAN Parties Troubleshooting Chapter 5: LANs and WLANs
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Question 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. Chapter 5: LANs and WLANs
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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 costs Sharing networked hardware can provide access to a wide range of services and specialized peripheral devices Chapter 5: LANs and WLANs
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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” computer Networked computers are susceptible to an increasing number of worms, Trojan horses, and blended threats Chapter 5: LANs and WLANs
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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 password Figure 5-41 Chapter 5: LANs and WLANs
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Sharing Files Figure 5-42 Chapter 5: LANs and WLANs
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Sharing Files Figure 5-43 Chapter 5: LANs and WLANs
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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 networking Figure 5-45 Chapter 5: LANs and WLANs
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Sharing Printers You can designate the printer attached to your computer as sharable over the network. Figure 5-46 Chapter 5: LANs and WLANs
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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 capability Figure 5-48 Chapter 5: LANs and WLANs
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Troubleshooting Network problems can stem from a variety of sources
Cables Signal strength Security Interference Network devices Settings Figure 5-49 Chapter 5: LANs and WLANs
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Security Through Encryption
Wi-Fi Security Encryption Chapter 5: LANs and WLANs
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Question 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. Chapter 5: LANs and WLANs
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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 area Figure 5-50 Chapter 5: LANs and WLANs
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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 PSK Activate encryption by using a wireless network key Chapter 5: LANs and WLANs
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Wi-Fi Security Figure 5-52 Chapter 5: LANs and WLANs
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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 algorithm Cryptographic key Chapter 5: LANs and WLANs
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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 method Chapter 5: LANs and WLANs
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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 message Figure 5-55 Chapter 5: LANs and WLANs
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Encryption When personal computer users want to encrypt or other documents, they turn to public key encryption software called PGP (Pretty Good Privacy) software Figure 5-56 Chapter 5: LANs and WLANs
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What Do You Think? 053100 Have you ever accessed a free WLAN?
A. Yes B. No C. Not sure Do you believe that rogue WLANs can survive alongside for-profit broadband ISPs? Are broadband providers justified in limiting the terms of their service agreements to “one subscription, one customer”? Chapter 5: LANs and WLANs
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Chapter 5 Complete LANs and WLANs
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