1. The Internet and World Wide Web

2. Objectives Define the concept of a network
Describe the components of a network
Define Internet
Discuss how the Internet works
Understand ways to access the Internet
Define Domain Name
Describe the components of the URL
Define World Wide Web (WWW)
Describe the components of the WWW

3. The Internet What is a network?
A collection of computers and devices connected together via communications devices and media
Modems
Cables
Telephone lines
Satellites
Next
p. 2.2

4. What Is a Computer Network?
Two or more connected computers
Major components in simple network
Client computer
Server computer
Network interfaces (NICs)
Connection medium
Network operating system
Hub or switch connecting multiple computers in a network
Routers
Device used to route packets of data through different networks, ensuring that data sent gets to the correct address

5. Components of a Simple Computer Network

6. Networks in Large Companies
Components can include:
Hundreds of local area networks (LANs) linked to firmwide corporate network
Various powerful servers
Web site
Corporate intranet, extranet
Backend systems
Mobile wireless LANs (Wi-Fi networks)
Videoconferencing system
Telephone network
Wireless cell phones

7. Corporate Network Infrastructure

8. Key Digital Networking Technologies
Client/server computing
Distributed computing model
Clients linked through network controlled by network server computer
Server sets rules of communication for network and provides every client with an address so others can find it on the network
Has largely replaced centralized mainframe computing
The Internet: Largest implementation of client/server computing

9. Key Digital Networking Technologies
Packet switching
Method of slicing digital messages into parcels (packets), sending packets along different communication paths as they become available, and then reassembling packets at destination
Previous circuit-switched networks required assembly of complete point-to-point circuit
Packet switching more efficient use of network’s communications capacity

10. Packet-Switched Networks and Packet Communications
Data are grouped into small packets, which are transmitted independently over various Communications channels and reassembled at their final destination.

11. Key Digital Networking Technologies
TCP/IP and connectivity
Connectivity between computers enabled by protocols
Protocols: Rules that govern transmission of information between two points
Transmission Control Protocol/Internet Protocol (TCP/IP)
Common worldwide standard that is basis for Internet
Department of Defense reference model for TCP/IP
Four layers
Application layer
Transport layer
Internet layer
Network interface layer

12. TCP/IP Reference Model
Application Layer
Defines the protocol that applications use to exchange data – FTP, SMTP, HTTP, HTTPS
Transport Layer
Provides communication session management between host computers.
Defines the level of service and status of the connection used when transporting data.
TCP
Internet Layer
Addressing, routing, and packaging data packets called IP diagrams – IP
Network Interface
Specifies details of how data is physically sent through the network, including how bits are electrically signaled by hardware devices that interface directly with a network medium, such as coaxial cable, optical fiber, or twisted-pair copper wire.

13. The Transmission Control Protocol/Internet Protocol (TCP/IP) Reference Model

14. Types of Networks Signals: analog vs. digital
Modem: Translates digital signals into analog form
Local-area networks (LANs)
Campus-area networks (CANs)
Peer-to-peer
Topologies: star, bus, ring
Metropolitan and wide-area networks
Wide-area networks (WANs)
Metropolitan-area networks (MANs)
Spans a city and sometimes major suburs

15. Network Topologies

16. Physical Transmission Media
Twisted-pair wire (modems)
simplest and slowest
Coaxial cable
Copper wires surrounded by thick insulation
Fiber optics and optical networks
Dense wavelength division multiplexing (DWDM)
Wireless transmission media and devices
Microwave
Satellites
Cellular telephones
Transmission speed (hertz, bandwidth)

17. The Internet What is the Internet? Also called the Net
A worldwide collection of networks that links billions of businesses, government agencies, educational institutions, and individuals

18. The Internet What are some of the services found on the Internet?
instant messaging
Web
file transfer
message board
chat

19. History of the Internet
How did the Internet originate?
Goal: To allow scientists at different locations to share information and work together on military and scientific projects
ARPANET
Networking project by Pentagon’s Advanced Research Projects Agency (ARPA)
Became functional in September 1969
Goal: To function even if part of the network were disabled or destroyed

20. History of the Internet
What is a host node?
University of California at Los Angeles
Also called a host
Any computer that directly connects to a network
Often stores and transfers data and messages
Provides network connections for other computers
Four original nodes on ARPANET
Stanford Research Institute
University of California at Santa Barbara
University of Utah

21. History of the Internet
What is NSFnet?
The National Science Foundation’s network
Five supercomputer centers
Connected to ARPANET in 1986
The Internet!
ARPANET
NSFnet

22. History of the Internet
How has this network grown?
Today
More than 1 Billion users
1984
More than 1,000 host nodes
1969 Four host nodes

24. From Research Project to Information Infrastructure
Growth In The Number Of Internet Hosts

25. The Web and Commercialization of the Internet
Growth Of The World Wide Web

27. New Structure for the Internet
The Internet is organized around four network access points (NAPs).
A different company operates each of these NAPs.
These companies sell access to the Internet through their NAPs to organizations and businesses.

28. New Structure for the Internet
Network Access Points On The Internet Backbone

29. May also provide a toll-free number
How the Internet Works
What is an Internet service provider (ISP)?
National ISP
Provides local telephone numbers in most major cities and towns nationwide
May also provide a toll-free number
A business that has a permanent Internet connection
Provides temporary connections to individuals and companies for free or for a fee
Regional ISP
Provides access to the Internet through one or more telephone numbers local to a specific geographic location
Next
p. 2.5

30. History of the Internet
Who provides the structure for the Internet today?
Telephone companies
Cable companies
Networks from corporations, commercial firms, and other companies
Government
Satellite companies

31. Online Service Provider (OSP) Wireless Service Provider
How the Internet Works
What are other service providers?
Online Service Provider (OSP)
Supplies Internet access
Has many members- only features that offer special content
Wireless Service Provider
Company that provides wireless Internet access

32. Newer high-speed technologies
How the Internet Works
How can you connect to the Internet?
Dial-up access
Home or small business
Computer, modem, regular telephone line
Dial into an ISP or OSP
High speed connection
Employees
Computers part of a local area network (LAN)
Connect to service provider through a high-speed connection line leased from local telephone company
Newer high-speed technologies
Home and small business
Digital subscriber line (DSL) – provides high-speed Internet connections over regular copper telephone line
Cable modem- provides high-speed Internet connections through cable television network

33. first part identifies network last part identifies specific computer
How the Internet Works
What is an Internet protocol (IP) address?
Number that uniquely identifies each computer or device connected to the Internet
Four groups of numbers, each separated by a period
Number in each group is between 0 and 255
IP address
first part identifies network
last part identifies specific computer

34. Tim Berners-Lee Created the World Wide Web
Director of the World Wide Web Consortium (W3C) at MIT

35. How the Internet Works What is a domain name? IP address 199.95.72.10
Text version of an IP address
Components are separated by periods
Each domain name represents one or more IP addresses
IP address
Domain name

36. How the Internet Works What is a top-level domain (TLD) abbreviation?
Identifies the type of organization associated with the domain
Sometimes called dot com when TLD is com
TLD Abbreviation
Type of Domain
Com
Commercial organizations, businesses, and companies
Edu
Educational institutions
Gov
Government agencies
Mil
Military organizations
Net
Network provider
Org
Non-profit organizations

37. The World Wide Web What is a Uniform Resource Locator (URL)?
Unique address for a Web page
Browser retrieves a Web page by using the URL
Also called a Web address
Type the URL into the address text box on the browser and press the Enter key to display a Web page
address text box

38. The World Wide Web What are the parts of a URL?
protocol
domain name
path
Click to view Web Link
then click URLs

39. History of the Internet
Who controls the Internet?
The Internet is a public, cooperative, and independent network
No single entity controls or owns the Internet
Several organizations advise and define standards
World Wide Web Consortium (W3C)
Oversees research and sets standards and guidelines
Internet2 (I2)
Internet-related research and development project
Develops and tests advanced Internet technologies

40. How the Internet Works What systems control domain names?
Internet Corporation for Assigned Names and Numbers (ICANN)
Group that assigns and controls TLDs
Domain name system (DNS)
System on the Internet that stores the domain names and their corresponding IP addresses
DNS server
Translates the domain name into its associated IP address

41. The World Wide Web What is the World Wide Web (WWW)?
Also known as the Web
A worldwide collection of electronic documents
Each document on the Web is called a Web page
Can contain text, graphics, sound, and video
Can contain built-in connections to other documents
A Web site is a collection of related Web pages

42. The World Wide Web What is a Web browser? Also called a browser
Software program that allows you to access and view Web pages
Two popular browsers for personal computers
Netscape
Internet Explorer
Next
p. 2.9 Fig. 2-6

43. Can take from a few seconds to several minutes
The World Wide Web
What is downloading?
The process of receiving information, such as a Web page, onto your computer from a server on the Internet
Can take from a few seconds to several minutes
You can speed up the display of pages by turning off the graphics and displaying only text in most Web browsers

44. The World Wide Web What is a hyperlink? Also called a link
Built-in connection to another related Web page or part of a Web page
Allows you to obtain information in a nonlinear way

45. The World Wide Web How can you identify a link?
Link can be a word, phrase, or image
Text links usually are underlined or in a color different from the rest of the document
A graphical link may change its appearance when you point to it
The shape of the pointer on the screen changes to a small hand with a pointing index finger when you position it on a link or point to the link
Click the link to activate it

46. The World Wide Web How do you navigate a variety of links? pointer
Some links display a different color when you point to them. Click the link to display its associated Web site or Web page.
pointer
Some links are underlined. Click the link to display the associated Web site or Web page.
pointer
Some links are graphical images. Click the link to display its associated Web site or Web page.

47. The World Wide Web What is surfing the Web?
Links can point to an item on the same Web page, a different Web page at the same Web site, or a separate Web page at a different Web site in another city or country
The activity of jumping from one Web page to another is surfing

48. The World Wide Web What is a search engine?
A software program you can use to find Web sites, Web pages and Internet files
Spider
A program that reads pages on Web sites in order to find Web pages that contain the search text
Also called a crawler or bot
Search text
A word or phrase entered in the search engine’s text box
Also called keywords

49. The World Wide Web What is a hit?
Any Web page name that lists as the result of a search
The fewer ‘hits’ the better
Point of searching the web is to narrow your search

50. The World Wide Web What is a directory? An organized set of topics
Used by a search engine to aid in locating Web sites
Each major topic has related subtopics

51. business/marketing Web page informational Web page
The World Wide Web
What are the six basic types of Web pages?
advocacy Web page
business/marketing Web page
informational Web page
portal Web page
personal Web page
news Web page

52. The World Wide Web What is an advocacy Web page?
Contains content that describes a cause, opinion, or idea
Purpose is to convince the reader of the validity of the cause, opinion, or idea

53. The World Wide Web What is a business/marketing Web page?
Contains content that promotes or sells products or services
Often allows you to purchase products or services online

54. The World Wide Web What is an informational Web page?
Contains factual information
Many U.S. government sites provide information

55. The World Wide Web What is a news Web page?
Contains newsworthy material
Stories and articles relating to current events, life, money, sports, and the weather

56. The World Wide Web What is a personal Web page?
A Web page maintained by a private individual who normally is not associated with any organization
Reasons: job hunting and sharing life experience with the world

57. The World Wide Web What is a portal Web page Often called a portal
Offers a variety of Internet services from a single, convenient location

58. The World Wide Web What services are often found on a portal?
search engine
sports and weather
stock quotes
newsgroups or message boards
local , national, and worldwide news
instant messaging
reference tools
maps
free personal Web pages
chat rooms
shopping malls and auctions
calendars
p. 2.17

59. newsgroup or message board
The World Wide Web
What is a Web community?
A Web site that joins a specific group of people with similar interests or relationships
Usually offer special services to facilitate communication among members
newsgroup or message board
online photo albums
chat room