Introduction to Internet Computing

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Introduction to Internet Computing

• Dan Wang

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Internet Computing

• Internet Computing Internet WWW
• A new computing paradigm that is evolved from
  growth of Internet and the WWW.
• Integrate Web-related technologies, such as the
  client/server model, Applet, XML, Web security,
  etc.
• Combine advantages of Internet and WWW
  technologies.

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Internet

• What is the Internet?
• A collection of a huge variety of resources that
  can be reached electronically.
• A community of people who communicate
  electronically, sharing ideas and information
  either on a one-to-one basis, or in groups.
• A distributed network based on the TCP/IP
  protocols.
• Internet has been used for over 30 years. At
  early days, Internet is used for simple
  communication applications. These applications
  mainly use simple command prompt interface and
  provide straightforward ways to read, navigate
  and search until WWW is created.

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WWW

• What is WWW?
• Acronym for World Wide Web.
• A hypertext-based, distributed information system
  initiated by Tim Bernes Lee in CERN.
• Hypertext is a technology for storing textual
  information with embedded cross references which
  are pointers to other information. (ex1)
• WWW introduces a new concept of user interface
  using hyperlink technology
• Link to text, graphics and sounds.
• Link to information located on different systems
  or locations.
• Provide a simple and uniform access to various
  resources on the network.
• Can be viewed as a repository collection of
  documents distributed across Internet.

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History of the Internet and WWW

• Internet and WWW are exploding like wild fire.
• Number of web servers in organization exceeds
  other servers
• More web-enabled applications in the last several
  years
• By 2004, only in Asia Pacific countries, over 95
  million people will spend HK17 billion online.

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History of the Internet and WWW

• 1957 USSR launches Sputnik, US formed Advanced
  Research Projects Agency (ARPA) as a response
• 1969, DoDs Advance Research Projects Agency
  (ARPA) initiated the idea of developing a packet
  switch network called ARPANET. It was started
  with only three services remote login (telnet),
  file transfer and remote printing.
• 1972, only 37 sites, email was introduced as one
  of the services.
• 1975, CCITT announced the X.25 standard based on
  packet switching but uses virtual circuit
  technology. X.25 hop-by-hop, while TCP/IP based
  on end-to-end principles.
• 1983, 500 sites. DARPA and UC Berkley work on
  implementing TCP/IP on BSD 4.2 Unix ARPANET
  split into two networks MILNET for military,
  ARPANET open for public.

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History of the Internet and WWW

• 1987, NSFNET was created. NSF supported for
  education and research. A high-speed backbone
  network ARPANET and NSFNET merged.
• 1989, Tim Bernes-Lee invented the WWW. Developed
  and released the protocols and HTML
  specifications.
• 1993, NCSA released Mosaic web browser for Unix
• 1994, Marc Andreessen left NCSA to start
  Netscape.
• 1995, Microsoft entered the Internet race with
  Internet Explorer 1.0.
• 1998, Larry Page and Sergey Brin set up Google
  Inc, a company that works on search engines.

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Internet Pioneers
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Internet Nowadays

• Consists of various interconnected networks
  ARPANET, NSFNET, CIX, BITNET, commercial
  networks, private networks, individual computers,
  PDAs, etc.
• Allows scientific, educational, research,
  commercial, and other applications. (Can you
  create new applications?)
• Keeps growing in a vary fast pace.

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Internet Applications

• Electronic mail (Email)
• Telnet
• File Transfer Protocol (FTP)
• Archie/Gopher/Veronica
• Wide Area Information Server (WAIS)
• Video conferencing (Netmeeting, CU-SeeMe)
• World Wide Web (IE, Netscape, FireFox)
• Instant Messenger (IRC, ICQ, QQ, Yahoo Messenger,
  MSN Messenger)
• VoIP (Skype)
• P2P (BitTorrent, eDonkey, eMule, Kazaa, etc.)

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Killer applications - Email
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Killer applications - FTP
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Killer applications WWW 1990-
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Killer applications P2P 2000-
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Killer applications- what next ?

• Media streaming (Internet TV)
• YouTube
• E-commerce
• Ebay, Amazon
• Online game
• PS3, XBOX 360
• Sensor networks

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WWW Applications

• WWW is one type of applications riding on the
  Internet, but it is a special one
• Applications
• Web browser
• Search engines

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Web Browser

• The web browser is the client-side software which
  interacts with the web server and performs
  invocation and interpretation of commands to
  exchange messages.
• May be window-based
• Mosaic/Netscape/Internet Explorer/FireFox
• May be text-based
• Lynx
• How to use?

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Web Browser

• There are three major components when the Web was
  created
• Uniform Resource Locator (URL)
• HyperText Markup Language (HTML)
• HyperText Transfer Protocol (HTTP)

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Web Browser

• Uniform Resource Locator (URL)
• uniformly address the location of the resources
  residing in the Web space.
• Three important components in a URL
• Protocol to access the resource
• Location of the server hosting the resource
• Name of the resource at the server
• E.g. http//www.polyu.edu.hk/staff.html,
  ftp//ftp.sura.net/pub/nic/agricultural.list

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Web Browser

• Hypertext Markup Language (HTML)
• With documents spanning across servers, there is
  need to have a way to organize the documents and
  standardize the display format.
• Designed to be simple and easy to learn.
• Success factors of HTML
• HTML directly supports the use of simple tag
  markups to provide hypertext reference to other
  related documents.
• HTML is specified using simple and standardized
  ASCII character codes that are open and platform
  independent.
• Require no special or proprietary tools to create
  and publish (compare to other software such as MS
  Word, Word Perfect, etc)
• True portability and content-independence of HTML
  allows publication of documents across
  heterogeneous servers and read by multi-platform
  clients

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Web Browser

• Hypertext Transfer Protocol (HTTP)
• Control and management protocol that coordinates
  the transfer of resources over the web.
• It defines a standard protocol for web
  components to communicate.
• Application layer protocol that runs over TCP/IP.
• Exchange of messages is in a form of
  client/server model using straightforward
  request-reply cycle.
• Client sends Request while server responses to
  the request.
• HTTP is a stateless protocol. Each request-reply
  cycle is independent, no state is maintained
  between cycles.

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Web Browser

• The architecture is comprised of three modules
• Controller module performs co-ordination
  functions between user input and invocation of
  other modules within the framework.
• Interpreter module contains all the interpreter
  drivers that are required to parse and interpret
  contents of the incoming documents. (What is the
  core interpreter of a web browser?)
• Service module houses all the drivers supporting
  the various transfer service protocol such as
  http, ftp, gopher, telnet and SMTP. (How do you
  specify the service to use in the web browser?)

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Search Engines

• Software programs to search for desired
  information on Internet
• Based on criteria specified by users.
• Composed of three major components
• Spiders (or crawlers)
• Indices (or catalogs).
• Searching engines (query processor).

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Search Engines

• Two major types of searches
• Keyword-based
• Exact/partial match
• Case in/sensitive
• Concept-based
• Context-sensitive
• May match synonyms
• Some popular search engines
• Google (http//www.google.com)
• AltaVista (http//www.altavista.com)
• Excite (http//www.excite.com)
• Yahoo (http//www.yahoo.com )
• Lycos (http//www.lycos.com)
• Mamma (http//www.mamma.com)
• Baidu (http//www.baidu.com) (Chinese search
  engine)

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Search Engines

• How does search engines work?
• A spider visits web pages, reads contents,
  follows links to other pages within the web page
• The web page is said being spidered, or
  crawled.
• It then builds an index, a giant list, of the
  visited web pages and information in them.
• This index forms a search engine database of
  searchable web pages.
• A site is visited regularly to keep information
  up-to-date.
• An actual search program (search engine) will
  then go through the database of searchable web
  pages to find matched indices to a search
  criteria.
• The search results are ranked in order of what it
  believes is most relevant.

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Benefits of Internet Computing

• Improve customers quality of service through
  directly participating and monitoring the
  customers workflow process online.
• Shortest path to the customers. By web-enabling
  services, company can immediately reach billions
  of customers worldwide directly.
• Low deployment cost. Internet and WWW is a dream
  marriage for companies. Low investment, and
  potentially high returns.
• Opportunities! Opportunities! Opportunities!
  Internet and WWW are creating more millionaires
  and businesses than any other business, e.g.
  Yahoo, Amazon, E-Travel, Google,anyone with an
  IDEA, a computer, and Internet access can start
  your own business.
• Ubiquity access. Web browsers everywhere! PC,
  Mac, Unix, Palm, GSM Phones, T.VThe universal
  software!!!

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Internet Organization

• No one runs the Internet
• Basic workings are coordinated by various
  technical groups
• The Internet Society (ISOC)
• The Internet Architecture Board (IAB)
• The Internet Engineering Task Force (IETF)
• The Internet Research Task Force (IRTF)
• The Internet Corporation for Assigned Names and
  Numbers (ICANN)

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Standardization

• Open standard of Web technology is an important
  driving force behind the popularity of the WWW.
• Although HTML and HTTP came from CERN and NCSA,
  these two entities has been superseded by W3C and
  IETF
• W3C is a vendor-neutral consortium to drive the
  development of web.
• IETF is the protocol engineering and development
  arm of the Internet. IETF steers standards
  through a series of RFC (Request for Comments).
  Starts off with Internet Drafts and may proceed
  to RFCs
• HTML has evolved from ver 1.0, 2.0, 3.2 to the
  latest ver 4 , while HTTP evolved from ver 0.9,
  1.0, to current 1.1

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Future of Internet Computing

• Interactive multimedia
• Video-on-demand
• Online gaming
• Electronic newspapers
• Electronic commerce
• Distance education
• Pervasive computing
• Mobile, wireless and ubiquitous
• More