Slide 1 © 2008 Prentice-Hall, Inc.. The Evolving Internet Slide 2 © 2008 Prentice-Hall, Inc.

Slide 1© 2008 Prentice-Hall, Inc.

The Evolving Internet

Slide 2© 2008 Prentice-Hall, Inc.

Explain how and why the Internet was created.

Describe the technology that is at the heart of the Internet.

Describe the technology that makes the Web work as a multimedia mass medium.

Discuss the tools people use to build Web sites.

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Discuss the trends that are changing the Internet and the way people use it.

Discuss some of the most important social and political issues raised by the growth of the Internet.

Describe various ways that governments restrict access to the Internet.

Slide 4© 2008 Prentice-Hall, Inc.

The Advanced Research Projects Agency NETwork (ARPANET) is the predecessor to the Internet: Developed at the request of the Department of Defense by a team of

visionary computer scientists Launched in 1969 Peer-to-peer networking philosophy and protocols were copied in other

networks in the 1980s Disbanded in 1990, having fulfilled its research mission, but its technology

spawned the Internet

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Counting ConnectionsThe Internet: an interconnected network

of thousands of networks Links academic, research, government, and

commercial institutionsConnects computers to about every

country in the world Growing too fast to measure its growth Internet is decentralized Internet doesn’t have hard boundaries

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Internet Protocols Transmission Control Protocol/Internet Protocol, TCP/IP…

At the heart of the Internet Allows cross-network communication

TCP breaks messages into packets. Each packet has all the information needed to travel from network to

network. Host systems called routers determine how to route transmissions. Packet-switching is flexible and robust.

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Internet Protocols IP is the address for the packets.

Each Internet host computer has a unique IP address. Each address is comprised of four sets of numbers separated by periods,

such as 123.23.168.22. NextGeneration Internet will allow more addresses and multicasting.

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Internet Addresses The host is named using DNS (domain name system),

which translates IP addresses into a string of names. Top-level domains include:

.edu - educational sites .com - commercial sites .gov - government sites .mil - military sites .net - network administration sites .org - nonprofit organization sites

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Internet Addresses .aero Air transport organizations .biz Businesses .coop Cooperative businesses such as credit unions .info Information services .museum Museums .name Personal registration by name .pro Licensed professionals, including lawyers,

doctors, and accountants

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An email address includes: [email protected] username is the person’s

“mailbox” hostname is the name of the

host computer and is followed by one or more domains separated by periods: host.domain host.subdomain.domain host.subdomain.subdomain.dom

ain

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[email protected]

User President whose mail is stored on the host whitehouse in the government domain

[email protected]

User hazel_filbert at the admin server for Grant MacEwan Community College in Alberta, Canada

Internet Access Options Direct (Dedicated) Connection

Computer has its own IP address and is attached to a LAN

No need to dial up Files are stored on your computer Quick response time

Dialup Connection Limited connection using a modem Full access dialup uses POTS or PPP via

modem

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Internet Access OptionsBroadband Connections

DSL Service Newer, faster, and cheaper than ISDN Can share phone line with voice traffic

Cable Modem Connection Allows Internet connections using shared TV cables Can exceed DSL speeds Carries increased privacy and security risks

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Internet Access Options Satellite connection provides connection

using DirecTV satellite dishes. Wireless broadband connection allows

multiple computers to connect to a base station using short-range radio waves.

Internet Service Providers (ISPs) Local ISPs provide connections through

local telephone lines. National ISPs offer connections on a

nationwide scale. Online Services like AOL and MSN offer

extra services.

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Internet Servers E-mail server acts like a local post office for a particular Internet host—a

business, an organization, or an ISP. File servers are common within LANs.

Also used to share programs, media files, and other data across the Internet File transfer protocol (FTP) allows users to transfer files.

Download files from remote servers to their computers Upload files to remote computers File compression saves storage space on disk and saves transmission time when

files are transferred through networks.

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Internet Servers Application server stores applications—PC office applications, databases,

or other applications. Makes them available to client programs that request them Might be housed at an application service provider (ASP), a company that

manages and delivers application services on a contract basis Web server stores Web pages and sends pages to client Web browsers.

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Web Protocols: HTTP and HTMLHTTP (Hypertext transfer protocol) used to transfer Web pages

HTML (HyperText Markup Language) created for encoding and displaying documents

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US.html

Protocol for Web pages

http:// weatherunderground.com/

Domain Name Resource File

satellite/vis/1k/

Path

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HTML is not WYSIWYG (What You See Is What You Get).

Publishing on the Web Programs that convert document format features into HTML

codes: Microsoft Word, PowerPoint, FileMaker

Web authoring programs: Dreamweaver, GoLive, Microsoft FrontPage

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By expanding the number of people who have the power to transmit knowledge, the Web might trigger a power shift that

changes everything.—Howard Rheingold, Virtual Communities

From Hypertext to Multimedia

Typical Web pages can contain:

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TablesFramesFormsAnimationsSearch Engines

Downloadable audio and video

Streaming audio and videoReal-time live

audio or video3-D environmentsPersonalization

Plug-ins and Helper Applications

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RealOneQuickTimeShockwave/FlashRealPlayerAdobe Reader and Acrobat

Dynamic Web Sites: Beyond HTML

Dynamic HTML Adds more programming power to HTML by allowing code

to automatically modify itself under certain circumstances

Languages for dynamic sites Perl scripting language Java: Full-featured, cross-platform, object-oriented

programming language

Slide 23© 2008 Prentice-Hall, Inc.

Dynamic Web Sites: Beyond HTML Java Applets: Small Java programs

Automatically downloaded onto client computer Can run on any platform

ActiveX: Collection of programming technologies and tools for creating controls or components

Similar in many ways to Java applets WML (Wireless Markup Language)

Helps create Web documents containing stock quotes, phone numbers, and other small nuggets of information

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Dynamic Web Sites: Beyond HTML

XML (Extensible Markup Language) Will replace HTML plus provide additional features and extensions

XHTML A sort of cross between HTML and XML

VRML (Virtual Reality Modeling Language) Creates 3-D virtual worlds

SMIL (Synchronized Multimedia Integration Language) Makes it possible to link time-based streaming media—sounds, video, and

animation can be tightly integrated

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Search Engines Search engines are designed to make it

easier to find information on the Web. Web Crawlers or Spiders

Software robots that systematically search the Web

Some search engines use keywords and Boolean logic to conduct searches.

Other search engines conduct searches using a hierarchical directory or subject tree.

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Specialized Search Engines: Google Maps, Froogle, and others

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Portals Web entry stations that offer quick

and easy access to a variety of services Consumer portals include search

engines,email services, chat rooms, references, news and sports headlines, shopping malls, and other services.

Corporate portals on intranets serve the employees of particular corporations.

Vertical portals are targeted at members of a particular industry or economic sector.

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Push Technology: Notifications and Alerts

The Web was built with pull technology. Browsers on client computers “pull”

information from server machines. Essentially, the browser asks for information.

With push technology, information is delivered automatically to the client computer. New product descriptions Automatic software upgrades Updated news

RSS (Really Simple Syndication) pushes (feeds) information to people who read blogs.

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Peer-to-Peer and Grid ComputingPeer-to-Peer (P2P) Computing

Users share music, movies, and other files without going through a central directory.

Use BitTorrent to download very large files.

Grid Computing Anyone can plug in from anywhere and rent processing

power and software from anywhere on the Net.

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Internet Issues: Ethical and Political Dilemmas

Filtering software to combat inappropriate content Digital cash to make online transactions

easier and safer Encryption software to prevent credit

card theft Digital signatures to prevent email forgery Access and censorship The digital divide

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From Cyberspace to Infosphere Paul McFedrie suggests that the Net today is like the

atmosphere—everywhere and necessary—and should be called our infosphere.

The Internet’s future depends on decisions we, as a society, make today.

The Net is evolving from a global community into a global intelligence.

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From Cyberspace to Infosphere

Kevin Kelly says the Internet “will evolve into an integral extension not only of our senses and bodies but our minds.”

In the Web, as in our brains, learning happens through ever-increasing interconnections.

As the Net changes, it changes our lives. Evolution of the Internet is far from over.

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The Internet is a network of networks that connects all kinds of computers around the globe and uses standard protocols to allow Internet communication to occur.

No single organization owns or controls the Internet.

You can connect to the Internet in several ways that provide different degrees of access to Internet services.

Most Internet applications are based on the client/server model.

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The Web uses a set of protocols to make a variety of Internet services and multimedia documents available to users through a simple point-and-click interface.

In addition to Web sites, a variety of applications are built on the protocols of the Internet and the Web. For example, people who use the Web depend on search engines to find the information they need.

Peer-to-peer computing was popularized by music-sharing services, but its applications go beyond music sharing.

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Many businesses are exploring ways to apply P2P technology.

Grid computing goes beyond P2P computing by enabling people to share processor power.

As the Internet grows and changes, issues of privacy, security, censorship, criminal activity, universal access, and appropriate Net behavior are surfacing.

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