The Internet

The Internet and the World Wide Web (WWW) are not synonymous. The Internet is the physical computer system that consists of an international internetwork of networks that link millions of computers and allow information to be transferred between any node within the system. The World Wide Web is the accessible information available, within the Internet which is in the form of documents, multimedia or any other standard file format available for transfer over the Internet.

What is the Internet?

  • A wide area network (WAN) that links millions of computers worldwide.
  • Began in 1969 as a research network ARPANET:
    • ARPANET scientists developed the Internet protocols (TCP/IP), standards that enable the transfer of data through the Internet,
    • sponsored by the US government,
    • linked Dept of Defence research centres and university researchers.
  • Other universities joined...
    • the net keeps growing with 150,000 new users per month (accurate?).
    • current estimate: 25 million users in 147 countries (old estimate).
  • Note that an internet (lowercase i) is any network of networks, but
    THE Internet (capital i) refers to the global network that anyone can access.
    This is a common mistake.

Genesis

  • The Web began at CERN, the European Centre for Nuclear Research.
  • CERN has several accelerators
    • Large teams of physicists use the accelerators for particle physics research
    • These teams may be scattered through many European countries
    • Experiments are extremely complex and require years of advance planning and construction of equipment
    • The web grew out of the need to have these large teams of dispersed researchers collaborate with a large collection of constantly changing documents such as reports and blueprints

     

  • A CERN physicist, Tim Berners-Lee proposed a web of linked documents in March 1989
  • First operational prototype of the web was running 18 months later
  • The first graphical interface for the web was released in February 1993, and was called Mosaic
  • Mosaic was so popular, its author, Marc Andreessen, left the NCSA (National Centre for Supercomputing Applications) and founded Netscape Communications Corporation.

(More on networks later in the course)

 

So Why the Success?

  • Design:
    • The Internet was designed during the cold war.
    • As it was not built around a central office, it could be easily disabled.
    • Therefore if one Internet node fails information is transferred or rerouted around the broken node.
  • Implications:
    • As it is distributed no one person or organisation owns the Internet.
    • Anyone can add a new node (computer or LAN) or pages (site) to the Internet.
  • The Internet
    • is based on information rather than technology
    • netiquette - a self-regulated system of behaviour
    • Blue ribbon campaign - to stop Internet censorship (but is that a good thing?)
  • Commercial Applications
    • E-Commerce is big business for businesses and web designers
    • businesses without a web site appear inferior

Limitations of the Internet

  • Not (yet) suited for transferring real-time voice and video.
  • The connection between two computers on the Internet is not guaranteed.
  • Transfer rates can be fast or quite slow depending on:
    • the time of day,
    • the amount of network traffic, and
    • the weather.
  • Two ways to improve Internet connections:
    • New hardware technology (e.g. faster modems/phone lines...)
    • New software technology (e.g. audio/video compression (MP3, Flash...))
  • Getting everyone to buy new hardware is obviously more difficult than downloading a new program.

Internet Access and Site Hosting

1. Types of Connections

1. Dial-up or Permanent Connection

  • A dial-up line (to any destination)
    • Allows connection to be established only when required (cheaper)
  • Permanent leased line is hardwired through the exchange to a single destination ( ISP)
    • Allows uninterrupted connection for when continuous or uninterrupted connection is required

2. Analogue or Digital Line Connection

  • Analogue using a normal phone line and modem or ISDN digital line

a) Analogue Lines

Allows connection to an ISP using a normal analogue phone line and modem. 

  • Maximum 56K (56,000 Bits per second) connection speed
  • Multiple modems may be pooled for increased throughput
  • WebRamp is a router that provides modem pooling for up to 3 modems

56K modem sites to investigate:

Modem share sites to investigate:

b) Digital Lines

Digital lines allow a direct interfacing of digital data without the need for modulation provided by an analogue modem. Digital lines are also higher quality, more reliable and offer greater data transfer rates. As a result they do not suffer noise and dropouts that are a problem for analogue lines.

Requires the installation of an ISDN line and ISDN terminal adapter (TA). This service is called OnRamp by Telstra and provides a range of high speed digital line options that start from 64K. ISDN lines are more expensive to install and maintain than normal analogue connections. 

  • OnRamp 1 provides 1 x 64K connection
  • OnRamp 2 provides 1 x 128K connection or 2 x 64 K connections 
  • Onramp 30 provides 1 x 1820K or any combination of 64K channels

Line Selection

Selecting the Correct Line Type and Speed

Number of Users

Connection Speed
1 to 4 56K Analogue modem
5 to 20 64K ISDN
20 to 50 128K ISDN
Large organisations 256K+ ISDN

Connection service to investigate:

Digital services to investigate:

2. Internet Service Provider (ISP)

An ISP provides connection to the Internet. Although other facilities are generally provided such as email and web site hosting, Internet hosting services for business applications are generally located with a commercial site hosting facility other than the ISP. That is OzEmail may be your ISP and your site may be hosted at WebCentral.

  • Analogue or high speed connections
  • Provide Dial up or permanent connection to ISP
    • Dial up connections disconnect periodically (say every 4 hours)
    • Permanent connections are more expensive and may be charged according to amount of data transferred
  • Direct Access
    • Uses a direct network connection to the Internet
      using the TCP/IP network protocol to transfer information.
    • This is how we access the Internet from the university
  • Dial-in Access
    • You use a modem to connect to a computer which has direct access.
      • Serial Line Internet protocol (SLIP), or
      • Point-to-Point Protocol (PPP).
    • With SLIP/PPP access you can:
      • view graphics
      • run graphical applications (eg. Netscape)
    • Without, you are limited to text-based displays.
  • Windows Dial Up Adapter
    • Found in the Control Panel for Windows 98/2000
    • Manages dialling through the modem and the PPP/SLIP connection
    • Simply set up through the Internet connection wizard on first use

    ISP links to investigate

Pricing (approximate)

  • Basic dial-up connection with 200M download from $25 per month
  • Permanent 56K connection from $300 per month
  • 256K ISDN dial in connection approximately $2500 per month ($3750 setup fee)

JCU allows dial-up access to its staff and students on 4781 4000, although it encourages them to use a normal ISP for regular (non-Uni) Internet access. InfoHelp has a How-To Guide on how to set this up, here.

3. Site Hosting

Site hosting services provide:

  • Storage space for web pages and data
  • Email facilities such as Email aliases, redirection and mailing lists
  • Web based email
  • Extra mail boxes
  • Purchase of individual IP addresses
  • Database support
    • Microsoft Access
    • Microsoft SQL Server
  • Database languages
    • CGI
    • Cold Fusion
    • ASP (Active Server Page)
  • E-Commerce Transaction facilities
    • Transaction server
    • SSL security
  • E-Commerce package support and online building facilities
    •  Intel iNetStore

Check out the commercial hosting facilities at:

E-Commerce Transactions and Security

E-Commerce transaction require two facilities

  • Must establish a merchant bank account (aquiring bank)
  • Must purchase an SSL Security Key

SSL (Secure Socket Layer) uses a 64 or 128 bit public encryption algorithm. A secure site will have a URL that begins with https://: rather than http://

Options:

  • Server or shared SSL key which is one key that covers all the business services on that server.
  • Individual SSL key which is registered against you IP address (purchased separately)
  • 40 bit key costing US$349 - basic key which is very secure - used by most businesses
  • 128 bit key costing US$849 - almost (?) unbreakable - used by large corporations such as banks

Can be purchased from

Building an E-Commerce Site

Web hosting services such as WebCentral and OzEmail offer the facility to build your business site on-line using Intel's iNETStore. This allows the incorporation of an your on-line database, storefront, shopping trolley and transaction facilities.

For more complex commercial sites a professional version of iNETStore may be purchased and installed on a PC to design the site.

Email

Electronic Mail

  • Used to send messages to other Internet users all over world.
    • Very efficient - send and receive a reply within minutes.
    • Typically less formal than pen and paper.
  • To send a message to someone you need an address.
  • An address comprises two components:
    • User name - identifies the sender or recipient
    • Domain name - identifies the computer system on which the user has an account
  • For example, to comment on the course, send me a message at either: 
    colin.lemmon@jcu.edu.au
colin@cs.jcu.edu.au

Email aliases

Mailing Lists

  • Often groups of people with a similar interest will form a mailing list.
  • For example - cp1030@jcu.edu.au.
  • Any mail message sent to the list gets reposted to each member of the list.
  • Lists can be moderated by an administrator or unmoderated.
  • You subscribe/unsubscribe by emailing the list administrator.
  • When the list becomes large:
    • a more diverse range of people are in the list
    • the volume of mail increases
    • probably better to start a news list or web page

Email Netiquette

  • The peril of email:
    • You read a message.
    • It makes you angry.
    • You reply...
    • You calm down.
    • You reread the message.
    • You've over-reacted or misread the message... 
  • For important messages consider seriously your reply over time.
  • Don't send junk mail or advertising material.
  • When using mailing lists:
    • read the list for a while before mailing a message,
    • make sure your message is relevant and concise,
    • don't reproduce private communications without consent,
    • send (un)subscription requests and personal emails to the administrator, not to the list.

 

Other Uses of the Internet

Uses of the Internet

  • Electronic mail
  • Usenet newsgroups
  • File exchange
  • Gopher & Wais
  • World Wide Web
  • Message Boards and Web Boards
  • IRC (Internet Relay Chat)
  • Internet Phone
  • Video conferencing
  • E-Commerce

Usenet News

  • Usenet is a world-wide distributed discussion system or forum.
  • They allow articles to be posted and read by members
  • Consists of a set of newsgroups.
  • Newsgroups are named hierarchically by subject.
  • There are thousands in number!
  • For example: 
    alt.beer       alt.buddha.short.fat.guy
aus.ads.jobs   jcu.forsale
jcu.announce   rec.aviation.aerobatics
rec.guns       rec.bicycles.off-road
  • Articles or messages are posted to newsgroups.
  • The articles are then broadcast to other interconnected computer systems.
  • Anyone (with appropriate software) can post & read news messages.
  • Extended in functionality by message boards and web boards
  • Netiquette:
    • Firstly read the group news.answers.
      • Answers for frequently asked questions (FAQs).
      • Guideline for posting messages.
    • Read the newsgroup for a week or so before posting a message.
    • Don't flame other news users.
      • Reduce the discussion to a personal level.

File Transfer (FTP)

  • The transfer of files and programs.
    • typically from a public archive
    • also between different computer systems to which you have access
  • Uses the File Transfer Protocol (FTP)
  • FTP archives can be searched by file name using the program archie.

Gopher & WAIS

  • Client-Server based information retrieval systems.
  • Once at a server you can:
    • retrieve information via a text-based menu
    • search the server by content or file-name
    • use a link to go to another server

Limitations of FTP, Gopher & WAIS

  • FTP, Gopher & Wais were developed with text-based user-interfaces.
  • Files were retrieved and stored on the local machine.
  • Separate programs were needed to access the information depending on the type of file.
  • Once computers and networks became powerful and affordable enough to
    • automate the file retrieval,
    • display multimedia documents
    • made the World Wide Web possible.

 

The World Wide Web

The World Wide Web (Web, WWW or W3)

  • A world wide hypermedia system.
  • Documents on the web contain multimedia formats:
    • Text
    • Images & Figures
    • Animation & Video
    • Sound
  • Also contain hyperlinks to other documents stored anywhere on the web.
    • Appear as:
      • highlighted or underlined images or text,
      • icons, or
      • hotspots in images.
  • Programs
    • Browser (Netscape, Internet Explorer, others)
    • Plug-ins - used to view content that the browser doesn't understand (extends its functionality)
      • e.g. when Flash animation came out, you had to download the Falsh plug-in so that your browser could use it.

Web Board or Message Board

  • Interactive extension of newsgroups that provide graphic user interface
  • Used for on-line forums
  • Also provide real time chat and an interface to Email
  • Usually controlled by a web board manager
  • Require registration and password identification to participate
  • May be used for conferencing or discussion groups

 Message Board

    • Generally non frame page that uses form components to post messages

 Web Board

    • Use frames and menu’s
    • Include chat facilities
    • Include email management facilities
    • Most require a JAVA capable browser

  

Internet Addressing - IP Addressing and Domain Names

The Uniform Resource Locator (URL)

The location of a page on the Internet is defined by the URL which identifies the web server or computer, the path to the page and the page filename. Each web server is identified using a unique IP (Internet Protocol) address which is registered with a world wide body to ensure that no two web servers have the same address. However as the management of these numbers is difficult, the Domain Name System (DNS) was developed to allow individual addresses to be registered against a domain name. 

The format of a URL is:

<protocol>://<domain name>/<directory path>/<file name>

Example:

http://www.cs.jcu.edu.au/teaching/Subjects/cp1030/2000/lectures/hardware/buyers_guide.html

if you do not specify the filename (e.g. http://www.cs.jcu.edu.au) then the server looks for the file "index.html" (UNIX) or "Default.htm" (Windows) and displays this file. If it doesn't exist, it displays a list of all of the files in the directory.

Note: not all WWW address have "www" in them.

eg.

Components

  • http:// is the protocol
  • www is the web root directory on server
  • microsoft is the domain
  • com is the top level domain extension 
  • any further sections i.e. /info/windows - would be part of the server directory structure

Top Level Domain Extension

Country Domain Extension
.com Commercial Organisation Australia .au
.org Non-profit Organisation Canada .ca
.net Internet company Germany .de
.edu Education Institution France .fr
.gov Government Japan .jp
.mil Military UK .uk

Sub Domains

  • The above domain is the primary or root domain of the web server
  • Some URL's do not start with www
  • These are subdirectories of the root directory that have been registered with a sub domain name

eg. 

  • (This used to be the case, but has now changed)
  • http://imp.jcu.edu.au
  • This is actually http://www.jcu.edu.au/imp
  • Both URL's will work - the second URL will be translated to the first
  • This may be visible in your browser Address window

Purchasing your own IP address and registering a domain name 

Email and Domain Names

Email uses the same system, but instead of specifying a page after the web site (domain)
        e.g. cs.jcu.edu.au/~colin

a user's address is included before the site, with an @ separating
        e.g. colin@cs.jcu.edu.au

 

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Last modified 15/08/00.