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. Slide 3 © 2008 Prentice-Hall, Inc.

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 Slide 5 © 2008 Prentice-Hall, Inc.

Counting Connections The Internet: an interconnected network of thousands of networks  Links academic, research, government, and commercial institutions Connects computers to about every country in the world  Growing too fast to measure its growth  Internet is decentralized  Internet doesn’t have hard boundaries Slide 6 © 2008 Prentice-Hall, Inc.

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. Slide 7 © 2008 Prentice-Hall, Inc.

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  NextGeneration Internet will allow more addresses and multicasting. Slide 8 © 2008 Prentice-Hall, Inc.

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 Slide 9 © 2008 Prentice-Hall, Inc.

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 Slide 10 © 2008 Prentice-Hall, Inc.

An address includes: m  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 Slide 11 © 2008 Prentice-Hall, Inc.

Slide 12 © 2008 Prentice-Hall, Inc. User President whose mail is stored on the host whitehouse in the government domain 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 Slide 13 © 2008 Prentice-Hall, Inc.

Internet Access Options Broadband 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 Slide 14 © 2008 Prentice-Hall, Inc.

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. Slide 15 © 2008 Prentice-Hall, Inc.

Internet Servers  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. Slide 16 © 2008 Prentice-Hall, Inc.

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. Slide 17 © 2008 Prentice-Hall, Inc.

Web Protocols: HTTP and HTML HTTP (Hypertext transfer protocol) used to transfer Web pages HTML (HyperText Markup Language) created for encoding and displaying documents Slide 18 © 2008 Prentice-Hall, Inc. US.html Protocol for Web pages weatherunderground.com/ Domain Name Resource File satellite/vis/1k/ Path

Slide 19 © 2008 Prentice-Hall, Inc. 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 Slide 20 © 2008 Prentice-Hall, Inc. 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: Slide 21 © 2008 Prentice-Hall, Inc.  Tables  Frames  Forms  Animations  Search Engines  Downloadable audio and video  Streaming audio and video  Real-time live audio or video  3-D environments  Personalization

Plug-ins and Helper Applications Slide 22 © 2008 Prentice-Hall, Inc.  RealOne  QuickTime  Shockwave/Flash  RealPlayer  Adobe 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 Slide 24 © 2008 Prentice-Hall, Inc.

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 Slide 25 © 2008 Prentice-Hall, Inc.

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. Slide 26 © 2008 Prentice-Hall, Inc.

Specialized Search Engines: Google Maps, Froogle, and others Slide 27 © 2008 Prentice-Hall, Inc.

Portals Web entry stations that offer quick and easy access to a variety of services  Consumer portals include search engines, 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. Slide 28 © 2008 Prentice-Hall, Inc.

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. Slide 29 © 2008 Prentice-Hall, Inc.

Peer - to - Peer and Grid Computing Peer-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. Slide 30 © 2008 Prentice-Hall, Inc.

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 forgery Access and censorship The digital divide Slide 31 © 2008 Prentice-Hall, Inc.

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. Slide 32 © 2008 Prentice-Hall, Inc.

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. Slide 33 © 2008 Prentice-Hall, Inc.

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. Slide 34 © 2008 Prentice-Hall, Inc.

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. Slide 35 © 2008 Prentice-Hall, Inc.

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. Slide 36 © 2008 Prentice-Hall, Inc.

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