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Computer networks are basically of two types – client/server
networks and peer-to-peer networks.
A client/server network is a network architecture where any
one of the computer or processes on the network can act as either a server or a
client. Although the term ‘client/server computing’ can be used to describe can
be used to describe a network, it is really more than just that. The term can
also be applied to describe software architecture.
The client/server software architecture was originally
developed to allow users, through the use of client programs, share access to
and interact with database applications, which acted as servers. Today server
programs do more than just act as databases but also do some processing of data
before it was passed on the client application. The amount of processing that
is done various amongst server applications.
The clients connect to the server applications which could
reside on the same computer or another computer via a network using a well
defined set of standard application program interfaces.
Some of the popular client/server applications can be found on
the Internet and they include email programs, FTP programs and web browsers.
Email client such as Microsoft Outlook and Pegasus allow users to download
email messages from email servers such as Eudora Internet Mail Server and
Microsoft Exchange Server. Internet browsers such as Microsoft’s Internet
Explorer, Netscape and Opera operate on the same principles by connecting to
the dedicated web servers and download web pages for viewing.
In term of computer networks, a server manages the resources
used, as well as their accessibility by other computers on the network. The
server should run on an operating system that allows other computers (clients)
connect to it. Ideally this should be a network operating system (NOS) such as
Windows NT Server, Windows 2000 Server, Linux, Novell Netware and OS/2.
Servers can also run operating systems such as Windows 95 and
98 and can be connected to by computers running the same operating system or
even Window NT Server (however this is not recommended). Desktop PCs,
minicomputers and some of the newer mainframes can act as servers in the
The clients are usually of two types – fat and thin clients.
Fat clients (usually PCs) tend to perform the bulk of processing of the data
that is stored on the server, while with thin clients the bulk of the
processing of the data is done by the server. Thin
client-server technology (TCST) has received a lot of attention in
healthcare, mainly due to the structure similarity with that of the mainframe
When compared to the peer-to-peer network, the advantages of
the client/server networking are:
The servers are designed to handle multiple requests from clients.
Resources, security and files are centrally controlled which makes it easier to
The network is more scalable as it allows for more users to be added as the
network grows, unlike the peer-to-peer networks, which are usually restricted
to a certain number of computers.
It is easier to implement new technologies with the client/server network.
It is possible to access multiple resources using a single client.
Its disadvantages include:
If the server goes down, it takes part or the whole network with it.
It is more expensive to install.
Needs to be maintained by staff with high IT skills.