This illustration shows a three-tier architecture using Oracle Database Cache.

• The client tier shows three PCs being used as Web browsers.
• The middle tier shows two nodes, each containing a Web server, an application, and a cache.
• The database tier shows one node as the database server, which contains the origin database.

Communication flows from the client tier to the middle tier then back to the client tier. An occasional request must be routed to the database server.