1. Computer Concepts – Illustrated Introductory, Seventh Edition
UNIT E:
Networks and the Internet

2. Computer Concepts – Illustrated Introductory, Seventh Edition
Objectives
Introduce networks
Classify networks
Explore network hardware
Explore data transport
Compare wireless and wired technology
Install a LAN
Computer Concepts – Illustrated Introductory, Seventh Edition

3. Computer Concepts – Illustrated Introductory, Seventh Edition
Objectives
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

4. 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

5. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing 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

6. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Networks
Ethernet
Significant network idea conceived by Bob Metcalfe in 1976
Transfers data between computers
Key element in nearly every computer network
Including Internet
Computer Concepts – Illustrated Introductory, Seventh Edition

7. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing 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

8. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Networks
Sharing networked hardware
Reduce costs
Expand access
Sharing networked software
Facilitate data sharing
Enable collaboration
Computer Concepts – Illustrated Introductory, Seventh Edition

9. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing 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

10. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing 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

11. Computer Concepts – Illustrated Introductory, Seventh Edition
Introducing Networks
Network connects computers and peripherals
Computer Concepts – Illustrated Introductory, Seventh Edition

12. Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying 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

13. Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying Networks
Networks Technologies
Computer Concepts – Illustrated Introductory, Seventh Edition

14. Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying 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

15. Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying 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

16. Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying Networks
Print server
Handles jobs sent to network printers
Workstation
Network client, usually personal computer
Computer Concepts – Illustrated Introductory, Seventh Edition

17. Computer Concepts – Illustrated Introductory, Seventh Edition
Classifying Networks
Peer-to-peer structure
Does not have a server
Workstations serve as both clients and servers
Computer Concepts – Illustrated Introductory, Seventh Edition

18. Exploring 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

19. Exploring 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 protocols
Computer Concepts – Illustrated Introductory, Seventh Edition

20. Exploring Network Hardware
If computer does not have Ethernet adapter,can purchased and installed
Computer Concepts – Illustrated Introductory, Seventh Edition

21. Exploring Network Hardware
USB and PC Ethernet adapters plug into ports on outside of system unit
Computer Concepts – Illustrated Introductory, Seventh Edition

22. Exploring 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

23. Exploring Network Hardware
Network Router
Computer Concepts – Illustrated Introductory, Seventh Edition

24. Exploring 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

25. Exploring Network Hardware
Networked peripheral
Any device with built-in network circuitry
Can connect directly to network
Network attached storage (NAS)
Storage device that directly connects to network
Computer Concepts – Illustrated Introductory, Seventh Edition

26. Exploring Data Transport
Communications channel (network link) - physical path or frequency for signal transmission
Used for transporting data
Computer Concepts – Illustrated Introductory, Seventh Edition

27. Exploring Data Transport
Wired network
Data travels from one device to another over cables
Wireless network
Data travels through air, no need for cables
Computer Concepts – Illustrated Introductory, Seventh Edition

28. Exploring Data Transport
Types of cables
Twisted pair
Shielded twisted pair (STP)
Coaxial (coax)
Fiber-optic
Computer Concepts – Illustrated Introductory, Seventh Edition

29. Exploring 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

30. Exploring Data Transport
Ethernet network cables terminated at each end with RJ45 connector
Computer Concepts – Illustrated Introductory, Seventh Edition

31. Exploring 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

32. Exploring 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

33. Comparing Wireless and Wired 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

34. Comparing Wireless and Wired 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

35. Comparing Wireless and Wired Technology
Range limits
Wired network - defined by longest cable in configuration
Wireless network - depends on type of signal, transmitter strength, and physical environment
Signal strength of wireless network
Computer Concepts – Illustrated Introductory, Seventh Edition

36. Comparing Wireless and Wired 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

37. Computer Concepts – Illustrated Introductory, Seventh Edition
Installing a LAN
Place router in central location, plug into surge protected outlet
Run cables from router to Ethernet adapter in each workstation
Run cable from Internet device and router’s WAN port
Turn on devices, computer should recognize and establish connection
Computer Concepts – Illustrated Introductory, Seventh Edition

38. Computer Concepts – Illustrated Introductory, Seventh Edition
Installing a LAN
Before using network, adjust router configuration settings
Computer Concepts – Illustrated Introductory, Seventh Edition

39. Computer Concepts – Illustrated Introductory, Seventh Edition
Installing 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

40. Computer Concepts – Illustrated Introductory, Seventh Edition
Installing 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

41. Sharing 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

42. Sharing 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

43. Sharing 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

44. Sharing Network Resources
File Sharing
Computer Concepts – Illustrated Introductory, Seventh Edition

45. Sharing 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

46. Introducing 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

47. Introducing Internet Technology
Connecting computer to Internet
Computer Concepts – Illustrated Introductory, Seventh Edition

48. Introducing Internet Technology
ISP equipment offers variety of services
, chat groups, IM capabilities, music file sharing, FTP, and more
Computer Concepts – Illustrated Introductory, Seventh Edition

49. Introducing 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

50. Introducing Internet Technology
Internet uses variety of communications protocols
Support 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

51. Introducing Internet Technology
Main Protocols used on Internet
Computer Concepts – Illustrated Introductory, Seventh Edition

52. Introducing Internet Technology
PING (Packet Internet Groper)
Sends signal to specific Internet address
Waits for reply
Reports elapsed time between sending and receiving signal
Traceroute
Records packet’s path from your computer to destination
Computer Concepts – Illustrated Introductory, Seventh Edition

53. Introducing Internet Technology
Connection options
Fixed Internet access - links to ISP from stationary point
Portable Internet access - allows easy movement of access device
Mobile Internet access – allows Internet use on the go
Computer Concepts – Illustrated Introductory, Seventh Edition

54. Exploring IP Addresses and Domain Names
IP address - Series of numbers
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

55. Exploring IP Addresses and Domain 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

56. Exploring IP Addresses and Domain Names
Dynamic IP addresses
Temporary address
Generally assigned to computers running client software for accessing Web, , listening to Internet radio, chat groups
Static IP address
Permanent address
Assigned to ISPs, Web sites, Web hosting services, servers
Computer Concepts – Illustrated Introductory, Seventh Edition

57. Exploring IP Addresses and Domain Names
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

58. Connecting to the Internet with Wires
Dial-up connection
POTS (plain old telephone service) is used to transfer data
Computer Concepts – Illustrated Introductory, Seventh Edition

59. Connecting to the Internet with Wires
Voiceband modem
Converts digital signals from computer into analog signals for telephone lines
Computer Concepts – Illustrated Introductory, Seventh Edition

60. Connecting to the Internet with Wires
ISDN (Integrated Services Digital Network)
Fixed Internet connection moves data over ordinary telephone lines
Use telephone wall jack as fixed point of connection
Connect computer to ISDN terminal adapter which sends digital signals
Computer Concepts – Illustrated Introductory, Seventh Edition

61. Connecting to the Internet with 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

62. Connecting to the Internet with 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

63. Connecting to the Internet with 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

64. Connecting to the Internet with Wires
Connecting to Internet via cable TV
Computer Concepts – Illustrated Introductory, Seventh Edition

65. Connecting to the Internet without 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

66. Connecting to the Internet without 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

67. Connecting to the Internet without 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

68. Connecting to the Internet without 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

69. Connecting to the Internet without Wires
WAP (Wireless Access Protocol)
Communications protocol providing wireless Internet access from handheld devices
Computer Concepts – Illustrated Introductory, Seventh Edition

70. Connecting to the Internet without 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

71. Computer Concepts – Illustrated Introductory, Seventh Edition
Talking Points: 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

72. Computer Concepts – Illustrated Introductory, Seventh Edition
Talking Points: 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