Web Multi tier Model Considerations

Installing LANSA on IBM i

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Web Multi-tier Model Considerations
  • In a multi-tier deployment model, you are using two separate machines for your Web Server and Data/Application Server. Two IP addresses are required: one to identify the Web Server and one to identify the Data/Application Server.
  • Only the Data/Application Server requires a full LANSA development environment installed. The LANSA Repository (including the generated HTML) and your application data are installed on this machine. The LANSA for the Web software is also installed on the Data/Application Server.
  • The Web Server will have a small component of LANSA for the Web installed. Its main task is to act as the interface between the Web serving software and LANSA for the Web. The Web Server does not require a LANSA system to be installed on it.
  • The Web Server can be an IBM i or a Windows server.
  • In an IBM i multi-tier deployment, you will be using IBM i servers for both the Web Server and Data/Application Server. The LANSA for the Web PC-based Administrator will only need to connect to the IBM i Data/Application Server.
  • You must configure Web Server to Data/Application Server communications using TCP/IP and a Listener.
  • Although the multi-tier model is a secure model for deploying your applications on the Web, there is a small performance overhead because of the link between the two machines as well as extra processing that has to be done by LANSA for the Web. This performance overhead may have an impact on the overall performance of your application.
  • As a variation to this model, you can use a firewall that is attached to the Web serving machine. The machine with the attached firewall will be connected to the Internet.
  • If you are installing LANSA for the Web using two IBM i servers, it is strongly recommended that you start with a single-tier installation. Once you have LANSA for the Web working in a single-tier environment, you can convert to a multi-tier installation. Refer to Task: Upgrade from a Single-tier to a Multi-tier IBM i Web Model.
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