18-10-2010, 03:22 PM
[attachment=6473]
Introduction
The most used network architecture is the client-server architecture. In a client-server
architecture the server passively waits for a request, until the client actively sends a
request to the server. The server then executes the request and sends the reply back to
the client.
One of the rst computer networks were isolated local area networks (LANs), with
a client-server architecture. The clients were cheap terminals, attached to a screen and
a keyboard. At the time, the clients required low network bandwidth. The only data
transmitted was the keyboard activity sent to the server, and the screen updates sent
back to the client.
The terminals used in these networks are classied as thin clients. This is because
most of the processing is done at the server, while the client typically process keyboard
input and screen output.
Some advantages with the thin client approach are:
A lower hardware costs, as there is usually no need for disk, a lot of memory, or
a powerful processor. This also creates a longer turnover time, because it takes
a longer period of time before the equipment becomes obsolete.
A lower administration cost, as the clients are almost completely managed from
the server. All installations and upgrades are done on the servers, and not on
each client.
A higher client reliability, as the client hardware has less points of failure.
Increased security, as no sensitive data ever resides on the client. The local
environment is usually highly restricted, and the protection against malware is
centralized on the servers.
The need to connection to other networks or clients from the existing network, created
the next step for computer networks. The connection between the networks was
typically created by leased lines or by dial-up connections. The new networks were
called metropolitan area networks (MAN) or wide area networks (WAN) depending on
the range of the networks. With the creation of these new networks, terminals could
now connect to other servers in other networks, and process data in other computer
environments.
Introduction
The most used network architecture is the client-server architecture. In a client-server
architecture the server passively waits for a request, until the client actively sends a
request to the server. The server then executes the request and sends the reply back to
the client.
One of the rst computer networks were isolated local area networks (LANs), with
a client-server architecture. The clients were cheap terminals, attached to a screen and
a keyboard. At the time, the clients required low network bandwidth. The only data
transmitted was the keyboard activity sent to the server, and the screen updates sent
back to the client.
The terminals used in these networks are classied as thin clients. This is because
most of the processing is done at the server, while the client typically process keyboard
input and screen output.
Some advantages with the thin client approach are:
A lower hardware costs, as there is usually no need for disk, a lot of memory, or
a powerful processor. This also creates a longer turnover time, because it takes
a longer period of time before the equipment becomes obsolete.
A lower administration cost, as the clients are almost completely managed from
the server. All installations and upgrades are done on the servers, and not on
each client.
A higher client reliability, as the client hardware has less points of failure.
Increased security, as no sensitive data ever resides on the client. The local
environment is usually highly restricted, and the protection against malware is
centralized on the servers.
The need to connection to other networks or clients from the existing network, created
the next step for computer networks. The connection between the networks was
typically created by leased lines or by dial-up connections. The new networks were
called metropolitan area networks (MAN) or wide area networks (WAN) depending on
the range of the networks. With the creation of these new networks, terminals could
now connect to other servers in other networks, and process data in other computer
environments.
