Computer
Network
In connection with the information
technology and computers a network is a way to connect computers together so
that they can communicate, exchange information and pool resources or a network
is a communicating system connecting two or more computers. Network connects
people as close as the next office and as for as halfway around the world.
In business networks have
revolutionized the use of computer technology. Many businesses that used to
relay on a centralized system with mainframe and a collection of terminals now
use computer networks in which every employee who needs a computer has personal
computer connected to the network. In education, schools, colleges and
universities have also shifted to strategies built around networked personal
computers.
Configurations
or Topologies Networks
A network can be arranged or
configured in several different ways. This arrangements is called the network’s
topology. The four principal network topologies are
1. Star Network
1. Star Network
2. Bus Network
3. Ring Network
4. Hierarchical Network
1. Star Network
In a star network small computers or
peripheral devices are linked to a central unit. This central unit may be a
host computer or a file server. All the communications pass through this central
unit. Control is maintained by polling. Each device is in turn allowed to send
the message.
One particular advantage of the star form of network is that it can be used to provide a time-sharing system. i.e several users can share resources (time) on a central computer. The star is a common arrangement for linking several microcomputers to a mainframe that allows access to an organizations database.
One particular advantage of the star form of network is that it can be used to provide a time-sharing system. i.e several users can share resources (time) on a central computer. The star is a common arrangement for linking several microcomputers to a mainframe that allows access to an organizations database.
2. Bus Network
In a bus network each device in the
network handles its own communication control. There is no host computer. All
communications control travel along a common connecting cable called a bus. As
the information passes along the bus it is examined by each device to see if
the information is intended for it.
The bus network is typically used when only a few microcomputers are to be linked together. The bus network is not as efficient as the star network for sharing common resources. However it is less expensive and is in very common use.
The bus network is typically used when only a few microcomputers are to be linked together. The bus network is not as efficient as the star network for sharing common resources. However it is less expensive and is in very common use.
3. Ring
Network
In a ring network, each device is
connected with two other devices forming a ring. There is no central file
server or computer. Messages are passed around the ring until they reach
correct destination. With microcomputers ring network is the least frequently
used arrangement. However it is often used to link mainframes specially over
wide geographical areas.
A ring network is useful in a decentralized organization because it makes possible a distributed data processing system i.e. computers can perform processing tasks at their own dispersed locations.
A ring network is useful in a decentralized organization because it makes possible a distributed data processing system i.e. computers can perform processing tasks at their own dispersed locations.
4. Hierarchical Network
This type of networks are also called
hybrid network. It consist of several computers linked to a central host
computer just like a star network. However these computers are also hosts to
other smaller computers or to peripheral devices. The host at the top of the
hierarchical network could be mainframe. The computers below the mainframe
could be minicomputers and those below microcomputers. This network allows
various computers to share database processing programs and different output
devices. It is useful in a centralized organizations.
Strategies of
Networks
Every network has a strategy or a way
of coordinating the sharing of the information and resource. The most common
network strategies are terminal, peer-to-peer and client/server systems,
terminal network system. In this system processing power is centralized in one
large computer, usually the mainframe. The nodes (a node is any device
connected to network) connected to this host computer are terminals (a terminal
is a input or output device) with little or no processing capability. Most
airline reservation
systems are terminal systems.
Peer-to-Peer Network System
In a peer-to-peer network, nodes can
act both as servers and clients. There are several advantages of using this
type of strategy. The networks as inexpensive and easy to install and they
usually work well for smaller systems with less than ten nodes. As the number
of nodes increases, however the performance of the network declines.
Client/Server Network System
Client/Server network system uses to
coordinate and supply services to all other nodes on the network. The server
provides access to centralized resources such as databases, applications
software and hardware. This strategy is based on specialization. Server nodes
coordinate and supply specialized services and client nodes request services.
One advantage of client/server
network system is its ability to handle very large networks efficiently.
Another advantage is the powerful management software that monitors and
controls networks activities. The major disadvantage of it is the high cost of
installation and maintenance.
Advantages of Network
Networks provide tremendous benefits.
The most compelling advantages of network are as follows.
1. Networks allow users simultaneous
access to shared programs and data.
2. Network also allows users to share peripheral devices such as printers and hard disks.
2. Network also allows users to share peripheral devices such as printers and hard disks.
3. Network usually includes the
capacity to send e-mail and many e-mail
systems let users to attach files to
their messages.
4. Connecting computers to form a
network makes it easier to perform backups of the data on all the network hard
disks.
Types of Networks
Communications differ in geographical
size. Three important types are LANs, MANs, WANs.
Local Area Networks (LANs)
Network with computers and
peripherals devices in close proximity within the same building are called
local area networks (LANs).
The figure shows an example of a LAN.
This type of arrangement has two benefits.
1. People can share different equipment, which lowers the cos of equipment.
2. LAN also features a network gateway. i.e. a LAN may be linked to other LANs or to large networks in this manner.
1. People can share different equipment, which lowers the cos of equipment.
2. LAN also features a network gateway. i.e. a LAN may be linked to other LANs or to large networks in this manner.
Metropolitan Area Network (MANs)
These network are used as links
between office buildings in a city. Cellular phone systems expand the
flexibility of MANs by allowing links to car phones and portable phones.
Wide Area Network (WANs)
Wide area networks are countrywide
and worldwide networks. Among other kinds of channels they use microwave relays
and satellites to reach users over long distances. One of the most widely used
WANs is Internet. Which allows users to connect to other users and facilities
worldwide.
Uses of
Internet
The most common uses of Internet are
1. Communicating
Sending and receiving e-mail is the
most popular internet activity. You can send and receive e-mail to and from you
friends and family located almost anywhere in the world. You can join an listen
to discussions and debates on a wide variety of special interest topics.
2. Shopping
One of the fastest growing
applications of Interest is electronic commerce. You can visit a cyber mall for
making purchases.
3. Researching
Internet provides you to have one of
the world’s largest libraries available from home.
4. Entertainment
Do you like music, the moves and
reading or playing computer games? You can find them all on Internet waiting
for you to locate and enjoy.
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