Intranet Application: client, server and database management layers.

This triangle gives a typical example of Intranet application partitioning services into three parts: client, server and data server. Each partition is a logical part of an application that can be independently distributed.
The three-tiered architecture divides applications into parts that run on different type of computers: clients, application servers and data servers.
The client partition contains the user interface, display, processing and startup code. This allows to run the application from the machine.
A data server partition contains one or more servers specifically dealing with database access.
An application server partition is responsible for all other services not so heavily accessing database. One ore more servers can be dedicated to the application server partition.
Web server with all the application code can be an example of application server implementation. Netscape browsers can be least expensive client part implementation.