This graphic has on the left the label "Clients" bounded by a dotted line. To its right is a "Firewall," and to its right is a column of two-sectioned boxes labeled "HTTP Server" and "Proxy plug-in". This column of boxes is labeled "Web Servers (Web tier)". To the right of this column is a column of boxes labeled "Servlet Cluster (presentation tier)". Each box contains the labels "JSP" and "Servlet". To the right of this column is another column of boxes labeled "Object Cluster (object tier)". Each box contains the label "EJB". On the top right is a Database.

Clients point to each of the HTTP Servers through the Firewall. Each of the HTTP Servers points as a group with three arrows to each of the boxes in the Servlet Cluster (presentation tier) and then to each of the boxes in the Object Cluster (object tier). Each of the boxes in the Object Cluster (object tier) points to the Database.