1. Sub topic : ARPANet and WWW
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2. Recap
In the previous class, you have learnt about
• Definition of a bridge
• Importance of a bridge
• Types of bridges
• Functioning of a bridge
• Definition of a gateways
• Function of gateways
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3. Objectives
On completion this topic, you would be able to know
about
• ARPA Net (Advanced Research Project Agency Net)
• WWW (World Wide Web)
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4. ARPA Network
• Advanced Research Project Agency (ARPA) was established
in 1969
• ARPANET was a large wide – area network created by the
United States Defense Department
• ARPANET served as a test bed for new networking
technologies, linking many Universities and research centers
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5. ARPA Network contd….
• The first two nodes that formed the ARPANET were
UCLA and the Standard Research Institute
• It has evolved into the Internet
• When the ARPANET migrated to the internet protocols in
1983, the major application protocols migrated along
with it
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6. E-mail
• In 1971, Ray Tomlinson of BBN sent the first network
email
• By 1973, 75% of the ARPA net traffic was email
File Transfer
• By 1973, the File Transfer Protocol (FTP)
specification had been defined and implemented,
enabling file transfer over the ARPANET
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7. Voice Traffic
• A Network Voice Protocol (NVP) specifications was
also defined (RFC 741) and then implemented
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8. ARPA Network contd….
• Network that has worldwide broadcasting capability, a
mechanism for information dissemination, and a medium for
collaboration , interaction between individuals and their
computers regardless of their geographical location
• The internet is a packet switched global network system that
consists of millions of local area networks and computers
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9. ARPA Network contd….
• In 1983, the U.S military portion of the ARPANET was
broken off as a separate network the MILNET
• Prior to this the ARPA consists of 113 nodes after that
the MILNET consists of 68nodes
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10. World Wide Web (WWW)
• The WWW (world wide web) is a system of interlinked,
hypertext documents accessed via the internet
• With a web browser, a user views web pages that may
contain text, images video and other multimedia
• .WWW are commonly found at the beginning of web
addresses
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11. World Wide Web (WWW) contd….
• The www today is a distributed client / server service , in
which client using a browser can access a service using
a server
• The service provided is distributed over many locations
called ‘sites’
• Each site holds one or more documents referred to as
web pages
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12. World Wide Web (WWW) contd….
• A web page is made up of two parts. The head and the
body
• The head is the first part of a web page. The head contains
the title of the page and other parameters that the browser
will use
• The actual contents of a page are in the body, which
includes text and the tag
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13. World Wide Web (WWW) contd….
• Each web page can contain a link to other pages
• The web pages are written in the HTML language i.e.
Hyper Text Mark up Language
• Web server is a program running on a server computer
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14. World Wide Web (WWW) contd….
• The web server constantly waits for a request for a web
page from browser program which runs on the client
• HTTP i.e. Hyper Text Transfer Protocol is a protocol
used mainly to access data on the www, which governs
the dialog between the client and server
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15. Architecture of www
Site A Site B
client
Request
Web page A
Request
Web page B Fig .1
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16. Architecture of www contd….
• Each web page can contain a link to other pages. The
client needs to see some information that belongs to site A
• Site A sends a request through its browser, that is
designed to fetch web documents
• Along other information the request includes the address of
the site and the web page called URL
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17. Architecture of www contd….
• The URL (Uniform Resource Locator) consists of for
example
http// www. yahoo. com / index
Protocol to be used
Domain name space Document / file name
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18. Architecture of www contd….
• The server at site A finds the document and sends it to
the client
• When the user views the document, she finds some
references to other documents, including a web page at
site B
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19. Summary
In this class, you have learnt about
• ARPANET
• WWW and its Architecture
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20. Quiz
1) URL stands for ____________________________
a) Uniform resource locator
b) Uniform register locator
c) Universal resource locator
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21. Frequently Asked Questions
1. Explain briefly about www
2. Write short notes on ARPANET
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