Client applications connected to multiple AppServers

A client application can connect to multiple AppServers on the same, or on different, machines. The following figure shows how this configuration might look with a client application connected to three different AppServers running (respectively) on one UNIX and two Windows machines.

In this scenario, the UNIX AppServer accesses a local database. Each Windows AppServer accesses the same remote database server (or DataServer) running on UNIX, which thus implements a three-tier distribution of application resources.