If you have the funds to implement this type of network, the return on the investment is great, and you will have the
knowledge that your network is well secured and archived.
Overview of Application-Server Networks
The final network type that I am going to cover is the Application Server based Networks, sometimes called Terminal
Server based. The idea behind this type of network is that you basically have one high-end server or mainframe, and all the
network clients are "dumb terminals", meaning that none of the processing is actually done on the terminals, instead the only job
the terminals have is to provide input and show the display on the monitor.
Most people equate application servers to the very old text-only terminals with no pointing devices. Today application
servers are very modern, and most people running on a "dumb terminal" will think they are working on a modern standalone
An Example of an Application-Server Network
I will use a Metropolitan Library located in a three story building, with 20 terminal computers on each floor as an example.
Each floor has its own Application Server running a version of Linux. Each application server has basic user applications,
such as Internet Browser, Word Processor, Spreadsheet Program, Email Application, Image Manipulation Program, as well as all
the basic applications you should find on a computer. Each Application Server serves applications to 20 different terminals,
which are older donated computers. Each terminal has the ability to run all of the above applications, print to any of the printers
on each floor and has access to the main card catalog through a web-based interface.
If one of the Application Servers goes down, the network is configured so that the terminals will log into one of the other
floors servers until the computer is repaired. If a terminal goes down, a replacement terminal can be installed with no downtime
for the entire network, with no information loss.
All the Application Servers also share a single /home directory from a separate File Server, which allows the library the
ability to offer an individual login name, email account and individual storage for a small charge. Along with the login name,
email account and storage, the patron also has the ability to access any files he may have saved on the file server through a secure
The Application Servers would cost the library roughly a total of $6000 ($2000 for each of them), the firewall costs $200,
the file server $1000, (all including setup fees) and all of the terminal servers were old donated computers. In total the library
offers to the public 60 different terminals, individual email accounts, and limited individual Internet storage, all for a total cost of
$7,200 (not including network wiring) or $120 for each terminal, including software.
Benefits of Application-Server Networks