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					                       Chapter 7

            The Internet, Intranets, and
                     Extranets
ITEC 1010          Information and Organizations
                       The Internet
      The internet
        A network of networks
        The internet transmits data from one computer
            (called a host) to another
      Internet networks
         Linked networks that work much the same
            way -- they pass data around in packets, each
            of which carries the addresses of its sender and
            receiver                                 Schematic

ITEC 1010             Information and Organizations
ITEC 1010   Information and Organizations
             Internet ‘Discussion’ (1)
A global network connecting millions of computers. As of 1999, the
Internet has more than 200 million users worldwide, and that number
is growing rapidly. More than 100 countries are linked into
exchanges of data, news and opinions.

Unlike online services, which are centrally controlled, the Internet is
decentralized by design. Each Internet computer, called a host, is
independent. Its operators can choose which Internet services to
use and which local services to make available to the global Internet
community. Remarkably, this anarchy by design works exceedingly
ITEC 1010              Information and Organizations
             Internet ‘Discussion’ (2)
well.

There are a variety of ways to access the Internet. Most online
services, such as America Online, offer access to some Internet
services. It is also possible to gain access through a commercial
Internet Service Provider (ISP).

Note: York University’s CCS (Computer and Communications
Services) is an ISP.
ITEC 1010              Information and Organizations
              How the Internet Works
      Transport control protocol (TCP)
         A protocol that operates at the transport layer and is
            used in combination with IP by most Internet
            applications
        Backbone
           An Internet high-speed, long distance communications
            links (like a bus; wire that connects nodes)
        Uniform resource locator (URL)
           An assigned address on the Internet for each computer
           E.g., http://www.yorku.ca/

ITEC 1010              Information and Organizations
                Domain Affiliations
            Domain   Affiliations
            arts     cultural and entertainment activities
            com      business organizations
            edu      educational sites
            firm     businesses and firms
            gov      government sites
            info     information service providers
            mil      military sites
            nom      individuals
            net      networking organizations
            org      organizations
            rec      recreational activities
            store    businesses offering goods for purchase
            web      entities related to World Wide Web activities
            net      networking organizations
ITEC 1010              Information and Organizations
               Access to the Internet
      LAN servers
            • Local servers can provide access to the Internet through
              normal connections (e.g., Ethernet)
      Serial line internet protocol (SLIP) and
       Point-to-point protocol (PPP)
            • Communications protocol software that transmits packets over
              telephone lines, allowing dial-up access to the Internet
      Connection via an on-line service
            • Examples are America Online and Microsoft Network. These
              services usually require sign-up procedures

ITEC 1010               Information and Organizations
            Three Ways to Access the
                   Internet




                                                 Schematic

ITEC 1010        Information and Organizations
ITEC 1010   Information and Organizations
              Internet Service Providers
      Internet service provider (ISP)
         Any company that provides individuals or
              companies with access to the Internet
             Thousands of providers including large
              communications companies
             Need an account with the ISP and software
              that links with TCP/IP


ITEC 1010              Information and Organizations
                          ISP Examples
       Internet Service Provider          Web Address
       AT&T WorldNet Service              www.att.com
       Digex, Inc.                        www.digex.net
       GTE Internetworking                www.gte.net
       IBM Internet Connection            www.ibm.net
       MCI Internet                       www.mci2000.com
       NetCom On-Line Communication www.netcom.com
       Services
       PSINet, Inc.                 www.psinet.com
       Sprint Internet Services           www.sprint.net
       Uunet Technologies, Inc.           www.us.uu.net

ITEC 1010                 Information and Organizations
                     Internet Services
             E-mail
             Telnet
             FTP
             Usenet and newsgroups
             Chat rooms
             Internet phone
             Internet videoconferencing
             Content streaming
ITEC 1010              Information and Organizations
            Selected Usenet Groups
 alt.fan.addams.family               alt.life.itself
 alt.pets                            alt.fan.bevis-n-butthead
 alt.autos.camaro                    alt.fan.leonardo-dicaprio
 alt.cloning                         alt.history
 alt.fan.u2                          alt.music.blues
 alt.sports.baseball.cinci-red       alt.music.zz-top
 alt.politics.socialism              alt.sports.college.sec
 alt.sports.soccer.european.uk




ITEC 1010         Information and Organizations
                   Internet Services
      Internet telephony
         Also called voice-over-IP (VOIP)
            • Technology that enables network managers to route
             phone calls and fax transmissions over the same
             network they use for data




ITEC 1010             Information and Organizations
ITEC 1010   Information and Organizations
                  VOIP ‘Discussion’
  Internet telephony is a category of hardware and software that
  enables people to use the Internet as the transmission medium for
  telephone calls. For users who have free, or fixed-price, Internet
  access, Internet telephony software essentially provides free
  telephone calls anywhere in the world. To date, however, Internet
  telephony does not offer the same quality of telephone service as
  direct telephone connections.
  There are many Internet telephony applications available. Some,
  like CoolTalk and NetMeeting, come bundled with popular Web
  browsers. Others are stand-alone products. Internet telephony
  products are sometimes called IP telephony, Voice over the Internet
  (VOI) or Voice over IP (VOIP) products.
ITEC 1010              Information and Organizations
                    Content Streaming
      Content streaming
            • A method for transferring multimedia files over the
                Internet so that the data stream of voice and pictures
                plays continuously, without a break, or very few of
                them
            •   It also enables users to browse large files in real
                time




ITEC 1010                Information and Organizations
              The World Wide Web
      World Wide Web
            • A collection of tens of thousands of independently-
             owned computers that work together as one in an
             Internet service




ITEC 1010             Information and Organizations
                WWW Terminology
      Home page
            • The cover page for a Web site that has graphics,
             titles, coloured text, etc.
      Hypermedia
            • Tools that connect the data on Web pages, allowing
             users to access topics in whatever order they wish
      Hypertext markup language (HTML)
            • The standard page description language for Web
             pages

ITEC 1010             Information and Organizations
            Some Interesting Web Sites

     Library of Congress               http://lcweb.loc.gov
     PointCast                         http://www.pointcast.com
     In-Box Direct                     http://www.netscape.com
     Online Career Center              http://occ.com
     New York Times                    http://www.nytimes.com
     Project Gutenberg                 http://www.gutenberg.org
     Sportsline USA                    http://www.sportsline.com
     White House                       http://www.whitehouse.gov
     MIT Lab for Computer Science      http://www.lcs.mit.edu
     The Wall Street Journal           http://www.wsj.com


ITEC 1010               Information and Organizations
                WWW Terminology
      Web browser
            • Software that creates a unique hypermedia-based
             menu on your computer screen and provides a
             graphical interface to the Web
      Web page
            • A screen of information sent to a requesting user
             and presented through a browser
      Applet
            • A small program embedded in Web pages

ITEC 1010             Information and Organizations
                      HTML
      “The” language of WWW pages
         Need we say more!!!




ITEC 1010       Information and Organizations
                        Search Engines
      Search engines
         A search tool for the Web (like card catalogs in
              libraries)
             E.g., Altavista      http://www.altavista.digital.com
                     Excite        http://www.excite.com
                     Galaxy        http://www.einet.net
                     Hotbot        http://www.hotbot.com
                     Infoseek      http://www.infoseek.com
                     Lycos         http://www.lycos.com
                     Webcrawler    http://www.webcrawler.com
                     Yahoo!        http://www.yahoo.com
ITEC 1010                 Information and Organizations
                             Java
      Java
         An object-oriented programming language
         Developed by Sun Microsystems
         Based on C++
         Allows small programs -- applets -- to be
            embedded within an HTML document



ITEC 1010           Information and Organizations
                        Applets
      Applets are small java programs that are
       downloaded from the server to the local
       machine




ITEC 1010         Information and Organizations
                      Push Technology
      Push technology
               • Technology that enables users to automatically
                receive information over the Internet rather than
                searching for it using a browser
               •Also called Webcasting
             E.g.,
               • PointCast
               • InterMind

ITEC 1010                Information and Organizations
            Webcasting ‘Discussion’
Using the Internet, and the World Wide Web in particular, to
broadcast information. Unlike typical surfing, which relies on a pull
method of transferring Web pages, webcasting uses push
technologies.




ITEC 1010              Information and Organizations
               Push ‘Discussion’ (1)
In client/server applications, to send data to a client without
the client requesting it. The World Wide Web is based on a pull
technology where the client browser must request a Web page
before it is sent. Broadcast media, on the other hand, are push
technologies because they send information out regardless of
whether anyone is tuned in.

Increasingly, companies are using the Internet to deliver information
push-style. One of the most successful examples of this is
PointCast, which delivers customized news to users' desktops.
ITEC 1010              Information and Organizations
               Push ‘Discussion’ (2)
Probably the oldest and most widely used push technology is e-mail.
This is a push technology because you receive mail whether you ask
for it or not -- that is, the sender pushes the message to the
receiver.




ITEC 1010             Information and Organizations
            Business Use of the Web
      Uses:
        Applications, E-mail, Product Display, Catalogs,
            Order placement
      Products people are likely to buy on the Web
             Software                        77%
             Books                           67%
             CDs                             64%
             Computer hardware               63%
             Airline tickets                 61%
             Magazine subscriptions          53%
             Concert/theater tickets         48%
             Flowers                         45%
ITEC 1010               Information and Organizations
              Intranets and Extranets
      Intranet
            • An internal corporate network built using Internet
             and World Wide Web standards and products that
             allows employees of an organization to gain access
             to corporate information
      Extranet
            • A network based on Web technologies that links
             selected resources of the intranet of a company with
             its customers, suppliers, or other business partners

ITEC 1010             Information and Organizations
                Intranet ‘Discussion’
A network based on TCP/IP protocols (an internet) belonging to an
organization, usually a corporation, accessible only by the
organization's members, employees, or others with authorization. An
intranet's Web sites look and act just like any other Web sites, but
the firewall surrounding an intranet fends off unauthorized access.

Like the Internet itself, intranets are used to share information.
Secure intranets are now the fastest-growing segment of the
Internet because they are much less expensive to build and manage
than private networks based on proprietary protocols.
ITEC 1010              Information and Organizations
                Extranet ‘Discussion’
A new buzzword that refers to an intranet that is partially
accessible to authorized outsiders. Whereas an intranet resides
behind a firewall and is accessible only to people who are members
of the same company or organization, an extranet provides various
levels of accessibility to outsiders. You can access an extranet only
if you have a valid username and password, and your identity
determines which parts of the extranet you can view.

Extranets are becoming a very popular means for business partners
to exchange information.
ITEC 1010               Information and Organizations
       Virtual Private Network (VPN)
      Virtual Private Network (VPN)
            • A secure connection between two points across the
             Internet
      Tunneling
            • The process by which VPNs transfer information by
             encapsulating traffic in IP packets and sending the
             packets over the Internet

                                                        Schematic

ITEC 1010               Information and Organizations
ITEC 1010   Information and Organizations
                   VPN ‘Discussion’
Short for virtual private network, a network that is constructed by
using public wires to connect nodes. For example, there are a
number of systems that enable you to create networks using the
Internet as the medium for transporting data. These systems use
encryption and other security mechanisms to ensure that only
authorized users can access the network and that the data cannot
be intercepted.



ITEC 1010              Information and Organizations
             Tunneling ‘Discussion’
A technology that enables one network to send its data via another
network's connections. Tunneling works by encapsulating a network
protocol within packets carried by the second network. For example,
Microsoft's PPTP technology enables organizations to use the
Internet to transmit data across a virtual private network (VPN). It
does this by embedding its own network protocol within the TCP/IP
packets carried by the Internet. (Note: PPTP = point-to-point tunneling
protocol)

Tunneling is also called encapsulation.
ITEC 1010              Information and Organizations
                       Internet Issues
      Management issues
         No centralized governing body for the Internet
      Service bottlenecks
         Phenomenal growth has left a service void
         Providers underestimating computing power
              needed
             Reconciling router addresses needed to
              transverse the network
ITEC 1010              Information and Organizations
                  Privacy & Security
      Cryptography
            • The process of converting a message into a secret code and
              changing the encoded message back to regular text
      Encryption
            • The original conversion of a message into a secret code
      Digital Signature
            • An encryption technique used for online financial transactions




ITEC 1010               Information and Organizations
            Have a
            nice day…           Encryption
                                software
                                running on
                                sending
                                computer


                                        E%$&:”}{|…



                                Decryption              Have a
                                software                nice day…

                                running on
                                Receiving
                                computer




ITEC 1010               Information and Organizations
                           Firewalls
      Firewalls
            • A method of preventing unauthorized access
             between a company’s computers and the Internet
             (looks at the header of a packet)
      Assured pipeline
            • An Internet security method that looks at the entire
             request for data and then determines whether the
             request is valid


ITEC 1010             Information and Organizations
            Firewall ‘Discussion’ (1)
A system designed to prevent unauthorized access to or from a
private network. Firewalls can be implemented in both hardware and
software, or a combination of both. Firewalls are frequently used to
prevent unauthorized Internet users from accessing private
networks connected to the Internet, especially intranets. All
messages entering or leaving the intranet pass through the firewall,
which examines each message and blocks those that do not meet
the specified security criteria.


ITEC 1010             Information and Organizations
               Firewall ‘Discussion’ (2)
There are several types of firewall techniques:
    Packet filter: Looks at each packet entering or leaving the network and
        accepts or rejects it based on user-defined rules. Packet filtering is fairly
        effective and transparent to users, but it is difficult to configure. In addition, it
        is susceptible to IP spoofing.
       Application gateway: Applies security mechanisms to specific applications,
        such as FTP and Telnet servers. This is very effective, but can impose a
        performance degradation.
       Circuit-level gateway: Applies security mechanisms when a TCP or UDP
        connection is established. Once the connection has been made, packets can
        flow between the hosts without further checking.
       Proxy server: Intercepts all messages entering and leaving the network. The
        proxy server effectively hides the true network addresses.

ITEC 1010                    Information and Organizations
             Firewall ‘Discussion’ (3)
In practice, many firewalls use two or more of these techniques in
concert.

A firewall is considered a first line of defense in protecting private
information. For greater security, data can be encrypted.




ITEC 1010               Information and Organizations
                      End




ITEC 1010   Information and Organizations

				
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