2. 1.0. INTRODUCTION
The Internet is a computer global system network. It’s
an acronym of International Network. The
research on dividing information into packets and
switching them from computer to computer began in the
1960s. The U.S. Department of Defense Advanced
Research Projects Agency (ARPA) funded a research
project that created a packet switching network known as
the ARPANET. ARPA focused research on ways that
networks could be interconnected, and the Internet was
envisioned and created to be an interconnection of
networks that use TCP/IP protocols.

3. Internet, computer-based global information system. The
Internet is composed of many interconnected computer
networks. Each network may link tens, hundreds, or even
thousands of computers, enabling them to share information and
processing power. The Internet has made it possible for people
all over the world to communicate with one another effectively
and inexpensively. Unlike traditional broadcasting media, such
as radio and television, the Internet does not have a centralized
distribution system. Instead, an individual who has Internet
access can communicate directly with anyone else on the
Internet, post information for general consumption, retrieve
information, use distant applications and services, or buy and
sell products.

4. 2.1.1. INTERNET TOPOLOGY
Connecting individual computers to each other creates networks. The Internet is a
series of interconnected networks. Personal computers and workstations are connected
to a Local Area Network (LAN) by either a dial-up connection through a modem and
standard phone line or by being directly wired into the LAN. Other modes of data
transmission that allow for connection to a network include T-1 connections and
dedicated lines. Bridges and hubs link multiple networks to each other. Routers
transmit data through networks and determine the best path of transmission.
All information is transmitted across the Internet in small units of data called packets.
Software on the sending computer divides a large document into many packets for
transmission; software on the receiving computer regroups incoming packets into the
original document. Similar to a postcard, each packet has two parts: a packet header
specifying the computer to which the packet should be delivered, and a packet payload
containing the data being sent. The header also specifies how the data in the packet
should be combined with the data in other packets by recording which piece of a
document is contained in the packet.

5. 3.0 CLIENT /SERVER ARCHITECTURE
Internet applications are based on the concept of client/server architecture. In a
client/server architecture, some application programs act as information providers
(servers), while other application programs act as information receivers (clients).
The client/server architecture is not one-to-one. That is, a single client can access
many different servers, and a single server can be accessed by a number of different
clients. Usually, a user runs a client application, such as a Web browser, that
contacts one server at a time to obtain information. Because it only needs to access
one server at a time, client software can run on almost any computer, including small
handheld devices such as personal organizers and cellular telephones

6. 3.1 HOW THE INTERNET WORKS
--- Dial –up connection Standard phone line Ethernet - - T1 connection Dedicated line
Fig 1.3: How Information travels over the Internet

7. 3.1.1INTERNET ACCESS
The term Internet access refers to the communication between a
residence or a business and an ISP that connects to the Internet. Access
falls into three broad categories: dedicated, dial-up, and wireless.
With dedicated access, a subscriber’s computer remains directly
connected to the Internet at all times through a permanent, physical
connection. Most large businesses have high-capacity dedicated
connections; small businesses or individuals that desire dedicated access
choose technologies such as digital subscriber line (DSL) or cable
modems, which both use existing wiring to lower cost. A DSL sends data
across the same wires that telephone service uses, and cable modems use
the same wiring that cable television uses.

8. Dial-up is the least expensive access technology, but it is also the least convenient.
To use dial-up access, a subscriber must have a telephone modem, a device that
connects a computer to the telephone system and is capable of converting data into
sounds and sounds back into data. The user’s ISP provides software that controls the
modem. To access the Internet, the user opens the software application, which causes
the dial-up modem to place a telephone call to the ISP. A modem at the ISP answers the
call, and the two modems use audible tones to send data in both directions. When one of
the modems is given data to send, the modem converts the data from the digital values
used by computers—numbers stored as a sequence of 1s and 0s—into tones. The
receiving side converts the tones back into digital values.
Wireless network is a kind of computers networks that does not require the use of wires
to connect to the Internet. The connectivity to the Internet with wireless network is
made easy through a wireless router. Wireless networks are categories into; LAN (Local
Area Network), PAN (Personal Area Network) and MAN (Metropolitan Area Network)
depending on the use.

9. 4.0. INTERNET APPLICATIONS
Apart from the World Wide Web that is generally use, some old applications are still used.
Telnet application enables a user to interactively access a remote computer. For example,
a businessperson who is visiting a location that has Internet access can use Telnet to contact
their office computer. Doing so is faster and less expensive than using a dial-up modem.
Another application, known as the File Transfer Protocol (FTP), is used to download files
from an Internet site to a user’s computer. The FTP application is often automatically
invoked when a user downloads an updated version of a piece of software. Applications
such as FTP have been integrated with the World Wide Web, making them transparent so
that they run automatically without requiring users to open them.
Network News discussion groups (newsgroups), is another application, Newsgroup
application software allows a user to obtain a copy of selected articles from a local news
server or to use e-mail to post a new message to the newsgroup. The system makes
newsgroup discussions available worldwide.

10. A service known as Voice Over IP (VoIP) allows individuals and
businesses to make phone calls over the Internet. Low-cost
services (some of them free) often transfer calls via personal
computers (PCs) equipped with microphones and speakers instead
of the traditional telephone handset.
Internet Protocol (IP) is a protocol used for communicating data
across a packet-switched internetwork using the Internet Protocol
Suite. IP is the primary protocol in the Internet Layer of the
Internet Protocol Suite and has the task of delivering distinguished
packets from the source host to the destination host based on their
addresses.

11. 5.0. USES OF THE INTERNET
Online Service,
provider of electronic news,
Information, and
e-mail services to customers connecting to the service with their
computers over modems and telephone lines. Online services
may also serve as gateways to other sources of information, such
as bulletin boards, chat groups, and the Internet. Popular online
services include CompuServe, the Microsoft Network, and
America Online.

12. 5.1. MARKETING AND THE INTERNET
The Internet enable marketers to promote their products and services to
millions of potential customers through the World Wide Web. This Web site
provides information about a product designed to keep vegetables fresh.

14. 5.3. ELECTRONICS NEWS
Electronic News is an online publication that currently covers just the
semiconductor production equipment industry. Electronic newspapers spared
publishers one of their highest expenses—newsprint—and many brought publishers
additional advertising revenue. The New York Times on the Web, an expert of
which is shown here, offers readers the same content as its print publication as well
as stories and features available only in its online version.

15. CONCLUSION
The Internet service has brought a greater development to various
continents. It entailed electronic commerce, which the companies used in
advertising, selling, buying, distributing of products, and providing
customers service. Telecommunication, is the use of e-mail which speeds
communication between the companies, coworkers, and among other
individuals. File sharing, individuals swap music, movies, photos,
applications and enable students to make a research work and download
materials. Online chatting, people carry on discussions using instant
messaging; share digital photo, video, and audio files, also play games in
real time; which cannot be compared to the late years.