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The Web at work
When the user looks at a Web page through the Internet, many things happen along the way. The thing that characterises the Internet is how data is transferred from one computer to another. How does the data get from one side of the world to the other? How can we transmit text and pictures through the Internet? This process of data transfer is possible because of dialup modem, ISDN, cable modem, wireless, leased line etc. But we have to decide only one medium as per requirement. Also computer connected to the Internet has software called TCP/IP (Transmission Control Protocol /Internet Protocol) that is responsible for receiving, sending and checking data in the form of packets. TCP/IP is a universal protocol which defines rules and regulations by means of which communication is possible. To reach any Web
server, your local ISP sends the packets of data to another ISP, which
may send them to another ISP. Thus the packets pass through a chain of
ISPs through nodal points to reach their destination. Your packets may
pass through fibre optic cables in the ground, satellites in the sky,
undersea cables or radio links. The TCP/IP protocol ties all links
together, enabling the packets to travel through the Internet. In order
to transmit text or pictures, the data is converted into small packets
that are routed through the Internet. But first they have to go to the
local ISP through an Intranet. This local ISP is a possible point of
failure in case the Internet is not working. If something goes wrong at
your local ISP, it may look like the Internet is broken. Whenever the
packets arrive at the Web server, the server sends responses back along
the available network path. When you are unable to reach the Web server,
the problem may be because of more network traffic, local ISP failure or
problem in the route of Web server . In particular, the biggest ISPs,
frequently called backbones, cover vast geographical areas and carry
large proporations of the Internet’s traffic. Now let us discuss about
fundamental protocols used for transmitting packets of data between two
remote systems over the Internet. E-mail sending and receiving is made
possible by Simple Mail Transfer Protocol (SMTP) or Post Office protocol
(POP). The Internet Relay Chat (IRC) is used for chatting. This is a
text-based mechanism that runs over the Internet. IRC clients provide
the user interface for typing, while IRC servers pass the information
back and forth, as well as organise the channels that are used for
chatting. |
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THE
Internet is a network of networks and is the world largest distributed
system. It is a worldwide mesh or matrix of thousands of networks, owned
and operated by thousands of people in hundreds of countries, all
interconnected by about 9,000 ISPs (Internet Service Providers). No
single organisation controls the Internet, not the biggest ISPs. The
Internet is different from other major basic services like telephony,
electricity etc. Four important services provided by the Internet are
Telnet, FTP (File Transfer), mail and general client/server facilities
etc.