2.1.6 LANSA for the Web on IBM i
The LANSA for the Web IBM i Architecture supports both single-tier and multi-tier installations.
A single-tier installation includes the Web Server and Data/Application Server on a single IBM i server.
A multi-tier installation uses two IBM i servers. The Web Server is located on one IBM i server and the Data/Application Server is located on a second IBM i Server. The LANSA for i software and the LANSA for the Web software are always installed on the Data/Application Server. For a multi-tier installation, additional Web components must be installed on the Web Server. LANSA for the Web supports CGI for communication.
Using a multi-tier model can provide an additional level of security by limiting the exposure of your Data/Application Server directly to the Internet.
You may use an IBM i to act as both your Web Server and Data/Application Server for your Internet applications. If this server is separate from your other internal production systems, a single-tier model is appropriate. If your Web site is used for an Intranet (which is not connected to the Internet), the single-tier model may be sufficient.
When using an IBM i, you may wish to start with a single-tier model. For example, you may use a single-tier model when you first install, develop and test your applications. Once you are ready to deploy your applications to the Internet, you may wish to use the multi-tier model.
Also see
Web Single-tier model Considerations
Web Multi-tier Model Considerations