2.
INTERNET
Introduction
Internet is a huge source
of enjoyable, important and up-to-the-minute information, which can be accessed
and shared by millions of people across the world. Every resource offered by
Internet is there because some person or group of people, somewhere in the
world, had an idea, developed it and then most important, made it available to
the entire world using internet or the ‘NET’, as it is commonly called.
Internet
is a collection of computer network that connects millions of computers around
the world for exchanging information. Basically internet is a product of
military undertaking. The Pentagon's Advanced Research Project Agency (ARPA)
funded the creation of internet in 1969 as ARPnet. The initial intention was to
develop a geographical dispersed reliable communication network for military use
that would not be disrupted in case of partial destruction from a nuclear
attack. The procedure developed for interconnecting ARPnet computer and
communicating the data was called TCP/IP (Transmission Control Protocol/Internet
Protocol). ARPnet allowed engineers and scientists working on military contracts
all over America Online share computers and computer resources. Later on
scientist developed a new procedure to exchange messages through a communication
network link called E-mail.
The number of computers
connected to internet has been growing exponentially. In 1983 there were less
than 500 host computers mostly in the Government laboratories and computer
science departments. By 1987 there were about 30,000 host computers at different
universities and research laboratories. By 1998 this number had increased to
more than 5 million hosts.
Internet evolved from a
small computer network set up in 1969. Way back then an American defence
department agency the Defence Advance Research Projects Agency, realized that
they needed to develop an easy way to exchange military information between
scientists and researchers based at different geographical locations. A simple
network of four computers, know as DARPANET, was therefore established.
The system caught on, although the name was soon
changed to ARPAnet, and by 1972 had grown to include 37 computers. At the same
time, the way in which the network was being used was changing. As well as just
using the system to exchange important, but boring, military information,
ARPAnet users started to send e-mail sometimes trivial, sometimes important to
each other by means of private mail boxes. They might not have realized it at
the time, but this quickly growing group of US defence workers had
started something big. Internet had begun and the era of free information
exchange was in. Tim Berners-Lee propose World Wide Web, in 1989 and later wrote
the first Web browser and server in 1990. The well-known web browsers like
Netscape Navigator and Microsoft Internet Explorer were dveloped, which are used
by the vast majority today. More than 36 million computers and 200 million users
are on Internet (survey of June 1998).
Internet
in India
History
and Status
Before
the appearance of VSNL’s GIAS, Internet had been in India for many years in
the form of ERNET. However, it was not possible for many people to get access to
it, as it was meant for only the educational and research communities. This
followed the policy laid down by the American Internet Manager NSF, at the time.
Educational
Research Network (ERNET)
Internet in India was established almost 10 years
ago, as ERNET. It was a joint undertaking of the Department of Electronic (DOE )
of the Government of India, and the United Nations Development Programme(UNDP),
which provides technical assistance to developing nations. ERNET is one of the
most successful operations that UNDP has funded. It established for India the
idea that we can participate in the Internet. Current ERNET operates many nodes
and has a 64 Kbps link to USA via Mumbai. All major nodes of ERNET are connected
to each other using 9600 bps leased lines. These lines are being ungraded to 64
Kbps links. Over 200 academic and R & D groups exchange e.mail with each
other using ERNET. Over 8000 scientists and technologists have access to ERNET
facilities. International access is provided over a 64 Kbps leased line, from
NCST, Mumbai to USA Plans for ERNET include the creation of a satellite
communication system to enable ERNET to reach locations, which do not have good
data communication links.
Gate
Internet Access Service (GIAS)
Videsh Sanchar Nigam
Limited (VSNL) India’s international trunk carrier and Gateway to the World
launched the Gateway Internet Access Service (GIAS) on August 15th
1995 for the first time on commercial basis in the country. VSNL has set up 6
Internet nodes that were established at Mumbai, Delhi, Chennai, Calcutta,
Bangalore and Pune. Each GIAS internet node is connected to internet via high
speed circuits from one of the following service providers: MCI (USA), KDD
(Japan), Telecom Italia and TELEGLOBE. A total approximately 40 Mbps bandwidth
is available for internet data transmission in and out of India. VSNL has got
other access nodes at Ernakulam, Cochin, Ahmedabad, Dehradun and Arvi. VSNL in
coordination with DOT has also launched Internet service at Lucknow, Hyderabad,
Kanpur, Chandigarh, Jaipur, Patana, Aurangabad, Gwalior, GOA, Pondichery,
Trivendrum, Keonics (Mysore) and Guwahati. Users in remote areas of India can
reach GIAS via I-NET. The Department of Telecommunication (DOT) has a widespread
network in India called I-Net, which has direct connectivity to each GIAS node
You can access GIAS from 99 cities in India by this means.
The GIAS network uses dual hub and spoke topology. There are six
gateways, which forms the backbone for the network. (Mumbai, Delhi, Chennai,
Calcutta, Bangalore and Pune) Mumbai is the central node. Each node is connected
to Mumbai with multiple high speed uplinks to Internet via different carriers.
The total uplink is more than 40 Mbps. Dynamic routing protocol ensures that the
shortest path to the destination is always chosen. Load balancing automatically
occurs if more than one equal cost path to the destination exists. The best
backup path is chosen when the primary path goes down. VSNL’s GIAS network is
multihomed to MCI, Telecom Italia and Teleglobe via the International
connections of the nodes, to ensure proper backup and redundancy at the carrier
level also.
All
the content of Internet is held by computers known as the “Servers” which
are owned by organizations and companies, eg. University of Kansas, Microsoft
etc. who want to distribute the information. When request is made of these
servers for the information, they bundle the requested information is small
packets, with address as to where it is to be sent, and send them down to the
nearest connection to the internet. When they arrive at the internet, the
packets are read by the router, which is nothing more than a traffic cop, and
sent down in the same general direction as the address. A similar thing happens
at the next junction on the Internet. This goes on till the packet is delivered
to the right address, where it is put together again with other packets, to make
up the original information. Says for example you are sending a message from
Mumbai to Lao Alto, California, to a server named svpal.org. The message will be
broken up into packets of approximately 1500 bytes, and some may travel from
VSNL here to the MCI router in the US some may travel to Madras and then to the
MCI router, and so forth. There is no predetermined path and even individual
packets of the same message may follow different paths. It all depends on the
traffic at the node, at the movement in time. As packets reach svpal.org, they
are all put together as in the original message and delivered to the given
address.
In
order to accomplish the task massaging across a network, computers use a
networking protocol. Taking the analogy of diplomacy, the relations and
interactions between the representatives of different countries follow a set of
rules laid down by tradition and treaty, which is called diplomatic protocol.
Similarly, all computers wanting to talk to each other have a conform to a
standard set of rules defined in the networking protocol. This enables different
type of computers running different types of operating system to communicate
efficiently. The de-facto standard today to TCP/IP. All this
is accomplished by dedicated but fast computers known as routes that work
in unison. Every organization has its own network and every individual user, his
own system and set up. What kind does not matter as long as they talk the same
protocol to the external world.
Domain
Name System (DNS):
The
domain name system was developed to solve this problem. DNS is a distributed
database. This allows local control of the overall databases, and yet the data
in each small segment is available across the entire network. Other than the
distributed nature. This allows responsibility for maintaining a domain to be
distributed and also allows for the information of the hosts tore side to
different computers. Since Internet was conceived and developed in the USA,
Americans defined the top level domains. Initially these were designated as
follows.
Com
For commercial organization (ie business)
Edu
Educational organization (Universities, schools)
Gov
Government organization (non military)
Mil
Military (army, navy etc)
Net
Network resources eg Internet Service Provider
Org
Other organization
These
national domain names follow an existing international official standard of two
letter abbreviations for every country in the world. An example of other
countries represented with domain include
Au
Australia
CA
Canada
Fr
France
UK
The United Kingdom
In
India
How to
get connected:
Basically there are four steps to getting connected
to the Internet. The first step is to get an account with VSNL. The second step
is to get a modem for your computer which is approved by DOT for use on
telephone lines, and computer hardware suppliers familiar with the internet can
guide you with that. The third step is to ensure that your computer hardware is
adequate for the type of account you have chosen, and the forth and last step is
to verify that you already have suitable communications software stored on your
hard disk, and if not to obtain and install the required software package.
Types
of accounts available and their cost:
There are basically two types of accounts available
the terminal account and the TCP/IP account. There are also two types of
connections to GIAS-dial-up and leased line. Depending on your status for
example, student, professional or commercial organization your costs will vary.
Where
to go and what to do:
The procedure involved in getting either the
Terminal account or a TCP/IP account is the same. Contact the VSNL customer
relations section in your city and get an application form and brochure. Fill up
the application attached the required Demand Draft taken in favour of VSNL and
send it to the customer relations section. Within a short time you will be
informed of your login name and password.
The minimum requirement for
accessing the Terminal account is either a VT 100/VT
220 type of terminal or a DOS machine. A 80386
processor machine with an adequate hard disk and 14.4 Kbps error correcting
modem will serve you well.
The minimum requirement for
accessing a TCP/IP account is a 80486 processor machine with 8MB RAM or having
similar processing power such as the Apple MAC At least a 14.4 kbps modem is
needed, and 28.8, 33.3 & 56.6kbps are also preferred if your line are noise
free. For an IBM compatible machine either windows 3.1 or windows95/98/2000
operating system is required for the TCP/IP.
With a DOS, a DOS based
terminal emulation programme is needed. There are many of tese programmes
available, either as shareware or commercially eg. Telix and Procomm Plus.
If you are using windows 3.1 or 3.11 system
software, appropriate 16 bit TCP/IP stack software will be required. Windows
95/98/2000 has built in TCP/IP stack software supplied with it, which has to be
installed and enabled. For Eudora you will need to supply your POP3 account
name, which for VSNL accounts is your e-mail address.
Programs
for accessing the Internet:
FTP:
"File-transfer protocol" i.e. accessing files that are stored on
remote computer system called sites.
TELNET: Helps
communicate with computer using Telnet protocol.
Lynx:
World-Wide Web information resource without graphics.
Netscape,
Mosaic & Microsoft Internet Explorer: Powerful web browser for
accessing the Web server with the
graphics.
RCP: The
RCP command allow to copy file from remote to local or between two remote hosts.
WAIS: Helps
search dozens of databases in one sitting.
Internet
Access by Email: Different sites on internet allow to access resources via email. Others
include FTP by e-mail, Archie by e-mail, Gopher by e-mail, WWW documents by
e-mail using an Agora WWW-mail server.
SEARCH
ENGINES:
These engines allow to
search the web pages by keywords, phrases, or question by displaying the list of
web pages. Few popular search engines are :www.yahoo.com,
www.lycos.com, www.infoseek.com,
www.excite.com, www.netscape.com,
www.altavista.digital.com, www.webcrawler.com
etc.
Applications:
1.
To communicate in various ways
2.
To share resources
3.
Find things that interest for user and
4.
Exchange information and files.
5.
To send and receive e-mails with people all over the world. Almost as
fast as the telephone, there is never a busy signal, and you never play phone
tag.
6.
Allows to join discussion groups about a common subject
7.
To access the information available on remote computer using mail
servers.
8.
To get or exchange software and files with the File Transfer Protocol
(FTP).
9.
Telnet lets you use the resources on a remote computer such as games,
databases, library catalogs, and many more interesting things.
10.
It
allow to connect to thousands of different computers using gopher menu systems
11.
To
explore the World Wide Web (WWW), which can use all of the above, and adds easy
links to other resources and adds multimedia--graphics, sound, and video
capabilities.
12.
To
talk by keyboard with Internet Relay Chat (IRC), which lets small groups of
users meet in conference to "talk" to each other by typing on their
keyboards.
13.
An
effective media for business communications.
14.
To
enjoy fun & games.
15.
To
have personal development.
Future
for Internet:
1.
International connections
2.
Commercialization
3.
Privatization
ELECTRONIC
MAIL (E-MAIL)
The
post office of the future:
E-mail, is a simple tool for exchanging brief text
messages between individuals or among a larger audience. E-mail is almost
certainly the most widely used application on internet and unsurprisingly so.
The advantages are numerous, the most obvious being speed. One of your e-mail
letters can arrive at its destination on the other side of the planet within
seconds of you hitting the Enter key on your keyboard. There are other
advantages, besides raw speed, too. You can send sound, images, video-even
computer software. E-mail has its disadvantages, of course. You can’t send
something physically. Each e-mail is made up of two parts, a heading and the
message. The heading is made up of the senders e-mail address and the
receiver’s e-mail address. An e-mail address serves a similar purpose to an
address on an envelop- the electronic postman needs to know where to send the
letter and to whom it’s intended. E-mail address can seem complex at first
glance, but they really are quite straightforward and logical once you look at
them more carefully.
1.
Send mail
2.
Read incoming mail
3.
Reply to mail
4.
Delete mail
5.
Exit the mail program
All mail programs have a New Message or Compose
E-mail command, located on a message menu, and they usually have a keyboard
shortcut for the command as well, such as Ctrl+N for New Message. When you start
a new message, your program will open a new window.
Type the address of the
person to whom you wish to send the mail. The person’s address must be of the
form username@address.domain
Username is the person’s identifier (the name they
log in with).
Address is the identifier of the person’s network or
machine on the network
Domain is the short code at the end indicating whether
the address is a business (.com)
A
non profit(.org), A university (.edu), A branch of the government (.gov), A part
of the military (.mil) and so on.
If you are sending mail to someone on your own network
(or another member of your online service or a subscriber of your own network
you only have to specify the username, not any of the Internet
information.
If you want to send mail to someone on another
network, you will need to know their identifier on the network address appears
in internet form. Here an example of the most common internet address.
Network
Username
Internet Address
Nagpur.dot.net.in jbtdrc
jbtdrc@nagpur.dot.net.in
After entering the recipient’s address in the
address box, press tab and then type a subject in the subject box(keep it
shortly) this will be the first thing
If you want to send a copy of the e-mail message to
more than one recipient , you can either:
Type that person’s
address on the cc: line
Type multiple addresses in
either the To: or Cc: line, separating each address by a comma. In some e-mail
programs, the addresses may appear on separate lines.
When you are done, send the
message or add it to a queue, a list of outgoing
messages to be sent all at once. Press the send button
Here are the steps for
reading an e-mail message
Open
your e-mail program by double-clicking its shortcut icon or selecting it from
the start menu. Some programs being by displaying your Inbox contents, and with
others you will need to click on a Get New mail button , or select Fileâ
Get mail or Get new mail. Others have a special mail menu selection, where you
choose Mailâ Get new Mail, or mailâ Read
Incoming Mail. Display your Inbox with the command appropriate for your program
If the message continues beyond the bottom of the
window, use the scroll bar to see the To view the contents of a mail message,
highlight it in the Inbox window and press Enter (or double-click it). The
message will appear in its own window.
If the message continues beyond the bottom of the
window use the scroll bar to see the next screenful.
After reading the message,
you can close or reply to the message
Somewhere near the New
Message command (probably on the same menu or button bar), You’ll find the
reply command.
Highlight the received
message in the Inbox or open the message, and then select the reply command
Your program will create a new message
automatically addressed to the sender of the message automatically include the
contents of the original message (or will give you the choice of including the
contents or not). Often, especially with e-mail programs that were designed
primarily for use on the Internet, the included message will appear with a
“>” character at the beginning of each line to indicate that it is quoted
text, although different mail programs have different ways of showing quoted
messages.
Sometimes, you’ll want to reply to everyone who
was sent a copy of the original message. Most e-mail programs offer a variation
on the normal reply command that includes all original recipients in your reply.
Select reply to all or a similar command to send your reply to everyone.
Tab to the subject line and
type a new subject if the old one isn’t very meaningful anymore.
Add other recipients if necessary or tab your way
into the message area to type your reply, and then choose the Send command when
you are done.
To delete a message, you
typically highlight it and press Delete.
When you are finished sending , reading , and
replying to mail , you can quite your program or leave it running to check your
mail at regular intervals.
You can quit most mail
programs by selecting File âExit
or File â Quite.
**********************