Page 30 - DCAP408_WEB_PROGRAMMING

Web Programming

Notes

Notes We may now define the HyperText Mark-up Language (HTML) as a standard format
for documents on the WWW, which could be viewed by using WWW browsers.
 URL: It denotes Uniform Resource Locator. It is the address of a document on the World
Wide Web. Web browsers enable a person to enter a known address of a web server or a
specific document within that server. Addresses begin with http://, ftp://, gopher://,
WAIS://, file:// etc.
 Protocols: They are sets of communication rules that enable client machines and servers
to communicate accurately with each other.

 Hyper Text Transport Protocol (HTTP): Hypertext Transfer Protocols are the rules that
enable the transmission of web documents from one computer to another via the Internet.
WWW is a client/server-computing environment. A client computer by clicking on a link
requests a document from Web server. In order to serve the request of client, Web server
uses a protocol called HTTP or Hyper Text Transport Protocol.

1.9.2 Internet and www Milestones

Early 1960s—Genesis of networking at The RAND Corporation, in a series of reports by Paul
Baran. Also, Leonard Kleinrock’s thesis “Communication Nets: Stochastic Message Early Flow
and Delay” at MIT created the model for performance evaluation and network 1960 design. The
concept of a “mesh network” of minicomputers that would use packet $ switching (in contrast to
circuit switching used in phone connections) to communicate over phone lines was a revolutionary
notion at the time. Until then, computer communications had centered on mainframes and
point-to-point links.
1965: One of the first networking experiments took place when the TX-2 computer at M.I.T.’s
Lincoln Laboratory was connected to a Scientific Data Systems Q-23 computer in Santa Monica,
California [HAF96].
1968: A request for proposal was floated to create the ARPANET; Bolt, Beranek, and Newman
(BBN) was awarded the prime contract. ARPA awarded other contracts to AT& T for
communications circuits, Network Analysis Corporation for designing the 1968 network
topology, the University of California at Los Angeles (UCLA) for a “network measurement
center”, and Stanford Research Institute (SRI) for a “network information center” Other sites on
the nationwide net included the University of Utah in Salt Lake City and the University of
California at Santa Barbara (UCSB).
1969: The first ARPANET node was installed at UCLA in September 1969, thus launching the first
packet switching network connecting SRI, UCSB, and University of Utah. The actual ARPANET
network that resulted used special-purpose computers known as IMPs (interface message
processors) to dismantle information into small chunks called packets, transmit the packetized
information to a destination computer known by an address, check for transmission errors,
retransmit damaged packets, and reassemble packets at the destination sites.

Did u know? What is Network Communication Protocol (NCP)?
To interface between the IMPs and proprietary software on the multivendor host computers,
the ARPANET researchers created Network Communication Protocol (NCP).
1971—In just two short years, approximately twenty nodes were installed, and ARPA was funding
thirty different university sites as part of the ARPANET program.

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