Computer Communication and Internet

Computer Communication and Internet
Basic Computer networks
What is a Local-Area Network (LAN)?
A local-area network (LAN) is a computer network that spans a relatively small area. Most LANs are
confined to a single building or group of buildings, however, one LAN can be connected to other LANs

over
any distance via telephone lines and radio waves. A system of LANs connected in this way is called a
wide-area network (WAN).
Most LANs connect workstations and personal computers. Each node (individual computer ) in a LAN

has
its own CPU with which it executes programs, but it also is able to access data and devices anywhere on
the LAN. This means that many users can share expensive devices, such as laser printers, as well as
data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat
sessions.
LANs are capable of transmitting data at very fast rates, much faster than data can be transmitted over a
telephone line; but the distances are limited, and there is also a limit on the number of computers that can
be attached to a single LAN.
 
Internet
What is Internet ?
The Internet is a global system of interconnected computer networks that use the standard Internet
protocol suite (TCP/IP) to link several billion devices worldwide. It is a network of networks that consists

of
millions of private, public, academic, business, and government networks, of local to global scope, that are
linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries

an
extensive range of information resources and services, such as the inter-linked hypertext documents and
applications of the World Wide Web (WWW), the infrastructure to support email, and peer-to-peer
networks for file sharing and telephony.
The origins of the Internet date back to research commissioned by the United States government in the
1960s to build robust, fault-tolerant communication via computer networks. While this work, together

with
work in the United Kingdom and France, led to important precursor networks, they were not the Internet.
There is no consensus on the exact date when the modern Internet came into being, but sometime in the
early to mid-1980s is considered reasonable. From that point, the network experienced decades of
sustained exponential growth as generations of institutional, personal, and mobile computers were
connected to it.
 
WAN
A wide area network (WAN) is a network that covers a broad area (i.e., any telecommunications network
that links across metropolitan, regional, or national boundaries) using leased telecommunication lines.
Business and government entities utilize WANs to relay data among employees, clients, buyers, and
suppliers from various geographical locations. In essence, this mode of telecommunication allows a
business to effectively carry out its daily function regardless of location. The Internet can be considered a
WAN as well, and is used by businesses, governments, organizations, and individuals for almost any
purpose imaginable.[1]
Related terms for other types of networks are personal area networks (PANs), local area networks

(LANs),
campus area networks (CANs), or metropolitan area networks (MANs) which are usually limited to a

room,
building, campus or specific metropolitan area (e.g., a city) respectively.