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Computer Concepts – Illustrated Introductory, Seventh Edition UNIT E: Networks and the Internet.
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Transcript of Computer Concepts – Illustrated Introductory, Seventh Edition UNIT E: Networks and the Internet.
Computer Concepts – Illustrated Computer Concepts – Illustrated Introductory, Seventh EditionIntroductory, Seventh Edition
UNIT E:
Networks and the Internet
ObjectivesObjectives
Introduce networks
Classify networks
Explore network hardware
Explore data transport
Compare wireless and wired technology
Install a LAN
Computer Concepts – Illustrated Introductory, Seventh Edition
ObjectivesObjectives
Share network resources
Introduce Internet technology
Explore IP addresses and domain names
Connect to the Internet with wires
Connect to the Internet without wires
Computer Concepts – Illustrated Introductory, Seventh Edition
Objectives
Talking points: Why pay for Internet access if you can get it for free?
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
Communications network -combination of hardware, software, and connecting links that transport data
Allow users to share resources – hardware, software, and data
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
EthernetSignificant network idea conceived
by Bob Metcalfe in 1976Transfers data between computersKey element in nearly every
computer network• Including Internet
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
Computer is on network if: computer can access other computers
or share hardware with other computers
Networks in home Access surveillance and monitoring
devices Control media devices Share hardware and software
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
Sharing networked hardware Reduce costs Expand access
Sharing networked software Reduce costs Facilitate data sharing Enable collaboration
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
Disadvantages of network connection Vulnerability to unauthorized access Susceptibility to malicious code
Most computer owners believe that advantages far outweigh disadvantages
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
Network is like spider web with many interconnecting points Node - each connection point
• Network nodes typically contain computers, networked peripherals, or network devices
Server Computer connected to network that
distributes resources to network users
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing NetworksIntroducing Networks
Computer Concepts – Illustrated Introductory, Seventh Edition
Network connects computers and peripherals
Classifying NetworksClassifying Networks
Networks - classified according to size and geographic structure PAN (personal area network) LAN (local area network) NAN (neighborhood area network) MAN (metropolitan area network) WAN (wide area network)
Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying NetworksClassifying Networks
Computer Concepts – Illustrated Introductory, Seventh Edition
Networks Technologies
Classifying NetworksClassifying Networks
Client / server network Must have at least one server and one
or more clients Network computers can serve as clients
or servers
Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying NetworksClassifying Networks
Server Computer that provides services to other
computers the network (clients)
Application server Runs application software for network
workstations
File server Stores files and supplies them to workstations
on request
Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying NetworksClassifying Networks
Print server Handles jobs sent to network printers
Workstation Network client, usually personal
computer
Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying NetworksClassifying Networks
Peer-to-peer structure Does not have a server Workstations serve as both clients and
servers
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
Network device Any electronic device that broadcasts
network data, boosts signals, or routes data to destination
Modems, network interface cards, hubs, switches, routers, gateways, bridges, repeaters
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
Modem Converts digital signals into signals that
can travel over network
Network interface card (NIC) Network circuitry needed to connect to
network
Ethernet card (Ethernet adapter) NIC designed to support Ethernet
protocolsComputer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
If computer does not have Ethernet adapter,can purchased and installed
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
USB and PC Ethernet adapters plug into ports on outside of system unit
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
Network hub Links two or more nodes of wired network
Network switch Sends data only to network devices specified
as destination
Network router Transmits data from one network to another Used to connect LANs and WANs
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
Computer Concepts – Illustrated Introductory, Seventh Edition
Network Router
Exploring Network HardwareExploring Network Hardware
Special hardware for wireless networks Transceiver
• Used to send and receive wireless data
MIMO (multiple-input multiple-output) technology
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Network HardwareExploring Network Hardware
Networked peripheralAny device with built-in network
circuitryCan connect directly to network
Network attached storage (NAS)Storage device that directly
connects to network
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Data TransportExploring Data Transport
Communications channel (network link) - physical path or frequency for signal transmission Used for transporting data
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Data TransportExploring Data Transport
Computer Concepts – Illustrated Introductory, Seventh Edition
Wired network Data travels from one device to another
over cables
Wireless network Data travels through air, no need for
cables
Exploring Data TransportExploring Data Transport
Types of cables Twisted pair Shielded twisted pair (STP) Coaxial (coax) Fiber-optic
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Data TransportExploring Data Transport
Buying cable - choose Category 5 (Cat 5) or Category 6 (Cat 6) Rating indicates capacity Higher number, higher capacity
Cables can be purchased in variety of lengths
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Data TransportExploring Data Transport
Computer Concepts – Illustrated Introductory, Seventh Edition
Ethernet network cables terminated at each end with RJ45 connector
Exploring Data TransportExploring Data Transport
Bandwidth Transmission capacity of communications
channel• High-bandwidth systems include cable and
DSL (broadband)• Systems with less capacity include dial-up,
referred (narrowband)
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring Data TransportExploring Data Transport
Other cables can be used to transport data over wired network USB, serial, parallel, SCSI, and FireWire
Wireless networks transport data via RF (radio frequency) signals Microwaves Infrared lights
Computer Concepts – Illustrated Introductory, Seventh Edition
Comparing Wireless andComparing Wireless andWired TechnologyWired Technology
Wired networks Fast, secure, reliable, simple to
configure
Wireless Provide mobility No unsightly wires or cables to tangle No need to run wires through walls,
ceilings, floors
Computer Concepts – Illustrated Introductory, Seventh Edition
Comparing Wireless andComparing Wireless andWired TechnologyWired Technology
Wired network is best choice if you need speed
Wired networks more secure than wireless networks Wireless signals pass through air and
can be intercepted more easily
Computer Concepts – Illustrated Introductory, Seventh Edition
Comparing Wireless andComparing Wireless andWired TechnologyWired Technology
Range limits Wired network - defined by longest
cable in configuration Wireless network - depends on type of
signal, transmitter strength, and physical environment
Computer Concepts – Illustrated Introductory, Seventh Edition
Signal strength of wireless
network
Comparing Wireless andComparing Wireless andWired TechnologyWired Technology
Prices have equalized between wired and wireless networks May need some additional equipment
for wireless• Wi-Fi card• Wireless access point
or router
Computer Concepts – Illustrated Introductory, Seventh Edition
Installing a LANInstalling a LAN
Computer Concepts – Illustrated Introductory, Seventh Edition
Place router in central location,plug into surge protected outlet
Run cables from router toEthernet adapter in each workstation
Run cable from Internet deviceand router’s WAN port
Turn on devices, computershould recognize andestablish connection
Installing a LANInstalling a LAN
Before using network, adjust router configuration settings
Computer Concepts – Illustrated Introductory, Seventh Edition
Installing a LANInstalling a LAN
Other ways to set up wired network HomePNA network uses telephone wiring in home Power-line network uses existing electrical wiring
Computer Concepts – Illustrated Introductory, Seventh Edition
Installing a LANInstalling a LAN
Power-line networks form infrastructure of LAN using existing electrical wiring Special NIC to connect computer to standard
electrical outlet
Computer Concepts – Illustrated Introductory, Seventh Edition
Sharing Network ResourcesSharing Network Resources
Wireless and wired devices can be connected to same network Most wireless routers include ports for
Ethernet cables and WAN port for cable to Internet device
Computer Concepts – Illustrated Introductory, Seventh Edition
Sharing Network ResourcesSharing Network Resources
Access network by clicking workgroup name May also have to enter password and
user ID
SSID (service set identifier) Helps log into correct network in places
where networks may overlap
Computer Concepts – Illustrated Introductory, Seventh Edition
Sharing Network ResourcesSharing Network Resources
To add workstations Turn on computer with wireless
capabilities Choose correct network Enter network key or passphrase
Workstation owners can specify whether files and locally attached printers can be accessed from other workstations on network
Computer Concepts – Illustrated Introductory, Seventh Edition
Sharing Network ResourcesSharing Network Resources
Computer Concepts – Illustrated Introductory, Seventh Edition
File Sharing
Sharing Network ResourcesSharing Network Resources
Three ways to connect printer to network using Windows Control Panel Connect it to one workstation in network Network print server Connect printer directly to hub or router
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Internet TechnologyIntroducing Internet Technology
Internet backbone Consists of high-speed fiber-optic cables
connecting high-capacity routers that direct network traffic
Provide main high-speed routes for data traffic
Network service providers (NSP) maintain backbone links and routers
NSP equipment and links are tied together by network access points (NAPs)
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Internet TechnologyIntroducing Internet Technology
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting computer to Internet
Introducing Internet TechnologyIntroducing Internet Technology
ISP equipment offers variety of services e-mail, chat groups, IM capabilities, music file sharing,
FTP, and more
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Internet TechnologyIntroducing Internet Technology
Upstream speed Rate of data transmitted from computer
to Internet
Downstream speed Rate of data arriving at computer
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Internet TechnologyIntroducing Internet Technology
Internet uses variety of communications protocolsSupport basic data transport and
services• TCP
– Breaks message or file into packets
• IP– Addresses packets so they can be routed
to destinations
Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Internet TechnologyIntroducing Internet Technology
Computer Concepts – Illustrated Introductory, Seventh Edition
Main Protocols used on Internet
Introducing Internet TechnologyIntroducing Internet Technology
PING (Packet Internet Groper)Sends signal to specific Internet
addressWaits for replyReports elapsed time between
sending and receiving signal
TracerouteRecords packet’s path from your
computer to destinationComputer Concepts – Illustrated Introductory, Seventh Edition
Introducing Internet TechnologyIntroducing Internet Technology
Connection optionsFixed Internet access - links to ISP
from stationary pointPortable Internet access - allows
easy movement of access deviceMobile Internet access – allows
Internet use on the go
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring IP Addresses and Exploring IP Addresses and Domain NamesDomain Names
IP address - Series of numbers 204.127.129.001 Each section called ‘octet’ Each address requires 32 bits Four sections create classes of IP addresses
• Based on size, type of network, other functions
ICANN (Internet Corporation for Assigned Names and Numbers)• Coordinates allocation of IP addresses, and
more
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring IP Addresses and Exploring IP Addresses and Domain NamesDomain Names
IP addresses - assigned by ISPs or network or system managers
IP addresses can also be obtained through DHCP (Dynamic Host Configuration Protocol)
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring IP Addresses and Exploring IP Addresses and Domain NamesDomain Names
Dynamic IP addresses Temporary address Generally assigned to computers running
client software for accessing Web, email, listening to Internet radio, chat groups
Static IP address Permanent address Assigned to ISPs, Web sites, Web hosting
services, email servers
Computer Concepts – Illustrated Introductory, Seventh Edition
Exploring IP Addresses and Exploring IP Addresses and Domain NamesDomain Names
Domain name Corresponds to unique IP address
entered into database called Domain Name System
Domain name server – any computer that hosts this database
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
Dial-up connection
POTS (plain old telephone service) is used to transfer data
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
Voiceband modem Converts digital signals from computer
into analog signals for telephone lines
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
ISDN (Integrated Services Digital Network)Fixed Internet connection moves data
over ordinary telephone linesUse telephone wall jack as fixed point
of connectionConnect computer to ISDN terminal
adapter which sends digital signals
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
DSL (digital subscriber line) High-speed, digital, always-on Internet access Uses standard phone lines to transport data Requires modem and filters
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
Dedicated line T1, T3, and T4 services - high-capacity
dedicated lines can be leased from telephone company
Not used by other customers
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
Cable connection Provides always-on broadband Internet
access over same infrastructure that offers cable television services
Bandwidth is divided to offer both television and Internet access
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwith Wireswith Wires
Connecting to Internet via cable TV
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwithout Wireswithout Wires
Satellite Internet service Means of distributing always-on, high-
speed, asymmetric Internet access Broadcasting signals to and from
personal satellite dish
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwithout Wireswithout Wires
Fixed wireless Internet service (wireless broadband) Internet access to homes and businesses
by broadcasting data signals over areas large enough to cover most cities and outlying areas
WiMAX (Worldwide Interoperability for Microwave Access) – well-known fixed wireless standard
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwithout Wireswithout Wires
Public Wi-Fi network Wireless LAN that provides open access
to public In many public places such as
bookstores, coffee shops, airports, hotels, and restaurants
Wi-Fi hotspot Range of Wi-Fi network’s coverage
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwithout Wireswithout Wires
Mobile WiMAX Designed to offer Internet access with
seamless handoff from coverage area of one tower to another
Portable satellite Internet service - available for those who need access when traveling in remote locations
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwithout Wireswithout Wires
WAP (Wireless Access Protocol) Communications protocol providing
wireless Internet access from handheld devices
Computer Concepts – Illustrated Introductory, Seventh Edition
Connecting to the InternetConnecting to the Internetwithout Wireswithout Wires
Mobile broadband Allows access to full
spectrum of Internet via handheld device
Requires fast connection, data service subscription, and mobile broadband equipment
Computer Concepts – Illustrated Introductory, Seventh Edition
Talking Points:Talking Points:Why pay for Internet access if you can get it for free?Why pay for Internet access if you can get it for free?
Free wireless LANs (WLAN) Found in airports, hotels, coffee shops Sometimes offered by rogue WLAN
operators who buy service, then distribute connections over wireless LANs to friends, neighbors, and anyone who passes by
But is this free access always legal?
Computer Concepts – Illustrated Introductory, Seventh Edition
Talking Points:Talking Points:Why pay for Internet access if you can get it for free?Why pay for Internet access if you can get it for free?
Problems include Piggyback use Data security
Providers feel every person using free Wi-Fi is one fewer customer
Wisdom of unregulated network availability is questioned by resulting ethical, security, and privacy issues
Computer Concepts – Illustrated Introductory, Seventh Edition