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Internet Inside the Internet and the Web Topics “It’s a bit like climbing a mountain. You don’t know how far you’ve come until you stop and look back.” Vint Cerf The Internet: A Network of Networks Internet Applications: Communication and Connection Inside the World Wide Web

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internet

Internet

Inside the Internet and the Web

topics
Topics

“It’s a bit like climbing a mountain. You don’t know how far you’ve come until you stop and look back.”

Vint Cerf

The Internet: A Network of Networks

Internet Applications: Communication and Connection

Inside the World Wide Web

The Evolving Internet

the internet a network of networks
The Internet: A Network of Networks

The Internet is an interconnected network of thousands of networks linking academic, research, government, and commercial institutions.

internet services
Internet Services

The Internet provides scientists, engineers, educators, students, business people, and others with a variety of services such as:

  • Electronic mail (send/receive mail messages)
  • Remote login(Telnet - access to other computers)
internet services5
Internet Services
  • Transferring files(FTP - accessing archives of data)
  • Newsgroups(Usenet - on-line public discussions)
  • World Wide Web(a collection of multimedia documents)
counting connections
Counting Connections

Today, the Internet connects computers to about every country in the world. However, the Internet is:

  • growing too fast to measure its growth
  • too decentralized to quantify
  • a network with no hard boundaries
internet protocols
Internet Protocols

The language at the heart of the Internet is TCP/IP…

  • Transmission Control Protocol/Internet Protocol
  • Allows cross-network communication
internet protocols8
Internet Protocols

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
internet protocols9
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
internet access options
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
  • Response time is quick
internet access options11
Internet Access Options
  • Dialup Connections
    • limited connection using a modem
    • Full access dial up uses SLIP or PPP via modem
  • Broadband Connections
  • DSL service is newer, faster, and cheaper than ISDN
  • Can share phone line with voice traffic
internet access options12
Internet Access Options
  • Cable Modem Connection
    • allow Internet connections using shared TV cables
    • can exceed DSL speeds
    • Carry increased privacy and security risks
  • Satellite Connections
    • provides connections using DirecTV satellite dishes
internet access options13
Internet Access Options
  • Internet Service Providers (ISPs)
    • local ISPs provide connections through local telephone lines
    • national ISPs offer connections on a nationwide scale
intranets and extranets
Intranets and Extranets
  • Intranets - self-contained intra-organizational networks designed using the same technology as the Internet
  • Firewalls - used to prevent unauthorized communication and secure sensitive internal data
intranets and extranets15
Intranets and Extranets

A typical Intranets include:

  • E-mail
  • Newsgroups
  • File transfer
  • Web publishing
  • Other services
intranets and extranets16
Intranets and Extranets
  • Extranets: designed for outside use by customers, clients, and business partners
  • Electronic Commerce:business transactions through electronic networks
intranets and extranets17
Intranets and Extranets
  • Electronic data interchange (EDI):a decade-old set of specifications for ordering, billing, and paying for parts and services over private networks.
  • Virtual private networks:not subject to the traffic and security problems.
internet applications communication and connection
Internet Applications:Communication and Connection
  • The user interface varies depending on which client/server application is being used.
  • UNIX- developed by Bell Labs, allows a timesharing computer to communicate with several other computers or terminals at once.
internet addresses
Internet Addresses
  • E-mail addresses are made upof two parts separated by an at(@) sign:
    • User name@host name
    • Example: johnsmith@mindspring.com
  • The host is named using DNS (domain name system), which translates IP addresses into a string of names.

“Each person on the “Internet” has a unique e-mail “address” created by having a squirrel run across a computer keyboard.”

Dave Barry

internet addresses20
Internet Addresses

An Internet address includes: username@hostname.sub.dom

  • 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.subdomain.domain
    • host.domain
    • host.subdomain.subdomain.domain
internet addresses21
Internet Addresses

Top level domains include:

  • .edu - educational sites
  • .com - commercial sites
  • .gov - government sites
  • .mil - military sites
  • .net - network administration sites
  • .org - nonprofit organizations
internet addresses22
president@whitehouse.govInternet Addresses

Examples:

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

User hazel_filbert at the server for Lane County, Oregon, k-12 school district

hazel_filbert@lane.k12.or.us

e mail on the internet
E-mail on the Internet

What appears on the screen depends on the type of Internet connection and mail program you use

Eudora is an easy to use Email software. Outlook and Netscape Communicator are popular e-mail software

e mail on the internet24
E-mail on the Internet
  • Why are free email accounts made available?
    • often offered to attract Web site visitors
    • available for users of public computers
    • sensible for those wanting multiple e-mail addresses not associated with a workplace
e mail on the internet25
E-mail on the Internet
  • EEmail Formats include:
    • ASCII text so they can be viewed with any client program
    • MIMEthat can be used to send and receive text with enriched text or HTML (displays text formatting, graphics, and links to Web pages)
mailing lists and network news
Mailing Lists and Network News
  • Mailing lists allow you to participate in email discussion groups on special-interest topics.
  • Network News are public discussions that you can go in and out as you please.
    • Messages are posted on virtual bulletin boards (for everyone to read).
real time communication
Real-Time Communication
  • Internet relay chat (IRC)allows several users to chat simultaneously
  • Internet Telephonyturns the Internet into a toll-free long-distance telephone service
  • Video teleconferences allow multi-person videoconferences via the Web
real time communication28
Real-Time Communication

See…

…Type

Hear…

telnet and ftp
Telnet and FTP
  • Information gathering
  • Telnet - makes remote login possible
  • FTP (file transfer protocol) - allows files to be uploaded and downloaded from remote computers
telnet and ftp30
Telnet and FTP
  • Web browsers locate and transfer files without typing commands
  • When you click a Web link to download a file, you’re probably usingFTP
inside the world wide web
Inside the World Wide Web
  • WWW is a distributed browsing and searching system developed at CERN
  • System was designed to give Internet documents unique addresses
  • HTML language was created for encoding and displaying documents
  • Browser software was built for viewing documents from remote locations
browsing the web
Browsing the Web

Web site Jargon:

  • Web pages are made up of text and images
  • A Web site is a collection of web pages
  • A Home page is the main entry to a Web site
  • A Web browser like Netscape Communicator or Internet Explorer allows you to explore the Web by clicking links
browsing the web33
Browsing the Web

Hyperlinks (links)are words or pictures that act as buttons, allowing you to go to another Web page

Links are typically underlined or displayed in a different color

more on browsing the web
More on Browsing the Web

More Web site Jargon

Links allow you to locate information without knowing its exact location (it may move from time to time)

Back and Forward buttons let you retrace your steps

Bookmarks and Favorites can be set up to mark your favorite Web locations

web addresses
Web Addresses

Pronounced Earl…like the name

A typical URL looks like this:

http://www.prenhall.com.beekman

web addresses36

Path to the host

http://

help/database.html

www.vote-smart.org/

Web Addresses

Protocol for Web pages

Dissecting Web Page address:

Resource Page

searching the web
Searching the Web
  • Search engines
    • produce a list of pages that match a keyword
    • they are built around a database that catalogs Web locations based on content
  • Directory or Subject Tree
    • A hierarchical catalog of Web sites
  • Natural Language Search Engines
    • Allows users to ask for what they want

“The ability to ask the right question is more than half the battle of finding the answer.”

Thomas J. Watson

search engines
Search Engines
  • Search engines help find information when you type a query using keywords.
search engines39
Search Engines
  • Directory/subject tree engines offer a menu of subject choices
search engines40
Search Engines
  • Ask questions in a Natural Language Search Engine
portals
Portals
  • Portals offer quick and easy access to a variety of services such as e-mail, chat,maps, news, shopping, etc.
  • Examples of consumer portals include
    • Yahoo!, Excite, Lycos, Alta Vista, Netscape Netcenter, Snap
    • Specialized portals target specific industries and economic sectors
from hypertext to multimedia
Tables

Frames

Forms

Downloadable audio and video

Streaming audio and video

Real-time live audio or video

3-D environments

From Hypertext to Multimedia

Typical Web pages can contain:

from hypertext to multimedia43
Plug-Ins are software extensions that add new features. Examples include…

QuickTime

Shockwave/Flash

RealPlayer

Acrobat

From Hypertext to Multimedia
webcasting push technology
Webcasting: Push Technology
  • Client computers pull information
    • Browsers initiate a request for information
  • Push technology delivers information automatically to the client computer
    • Up to the minute weather reports
    • News headlines
publishing on the web
An HTML document includes codes that determines the format, layout, and structure of a Web documentPublishing on the Web

HTML (Hypertext Markup Language)

HTML is not WYSIWYG

publishing on the web46
Publishing on the Web

This text coded as HTML …

  • <H1>Welcome to Computer Confluence</H1><b>Publishing on the Web</b>

Appears like this on the screen …

publishing on the web47
Publishing on the Web
  • Alternatives to HTML…
  • Programs that convert document format features into HTML codes
    • Microsoft Word, FileMaker
  • Web authoring programs
    • HomePage, GoLive, FrontPage
beyond html
Beyond HTML

Dynamic HTML:

adds more programming power to HTML by allowing code to automatically modify itself under certain circumstances

JavaScript:a simple language for enhancing HTML Web pages

beyond html49
Beyond HTML
  • WML
  • Wireless Markup Language helps create Web documents containing stock quotes, phone numbers, and other small nuggets of information

XML

  • Will replace HTML plus provide additional features and extensions

VRML

  • Virtual Reality Modeling Language creates 3-D virtual worlds
beyond html50
Beyond HTML

Java

  • A full-featured, cross platform, object-oriented programming language

Java applets

  • Small Java programs that can be automatically downloaded onto your client computer and can run on any platform
the evolving internet
The Evolving Internet
  • provides faster network communications for universities and research institutions
  • virtual laboratories, digital libraries, and distance learning applications are being built on Internet 2

Internet2 and the Next Generation Internet

internet issues
Internet Issues
  • Filtering software can prevent unwanted and inappropriate content
  • Encryption prevents credit card and e-mail forgery
  • Digital cash makes on-line transactions safer
  • Universal access is a problem

Ethical and Political Dilemmas

internet everywhere the invisible information
Internet Everywhere: The Invisible Information
  • A blurring of Web and interpersonal communication applications
  • Internet appliances connected to the Web
  • Continued computer crime and security issues

What Next? Electronic Frontier