This is the same image that was used in Lesson 2 - the only difference here is that the file server and database server together are circled and labeled as a “data tier.”
At the top is a drawing of a computer with the label: Web client applications. The computer image extends into a little cloud with the label: External Internet.
A line extends from the bottom of this cloud into a wide oval diagram with the label: Internal network. The line leads to the drawing of a Web server and then, below the Web server, to a Geospatial server. The line then branches to drawings of a file server (left) and a database server (right). The file server and database server together are circled and labeled as “data tier.” To the left (within the Internal network oval) is another computer drawing with the label: Administrators and internal client applications.