A wide variety of client workstations can access iSeries services through iSeries Access for Windows functions when the product is installed on the middle tier of a three-tier environment.
Additionally, three-tier environments present several other advantages:
All three-tier environments separate components and applications into three layers. The three layers may reside on separate PCs, or terminals, and communicate over a network. Generally the tiers will have the following characteristics:
This layer contains the interface and applications that allow end users to manipulate data. For example, this may involve a Web browser running on a network station, or a custom-built application using a remote component. This layer does not use the iSeries Access for Windows client.
This layer contains the business or application logic. In iSeries Access for Windows environments, this layer should consist of a Windows server running a Microsoft Active Server Pages script or a remote component.
This layer uses Microsoft's Internet Information Server (IIS) and can, optionally, use Component Services or Microsoft Transaction Server for distributed transactions. The script uses the ADO.NET provder, OLE DB provider, or ODBC driver that are included with iSeries Access for Windows. These clients communicate with the database tier to get the DB2 for i5/OS database data.
Refer to the following topics for more information about the middle-tier:
This layer usually consists of a DB2 for i5/OS database. Your applications can access this and various iSeries services through host server programs, or through custom-built iSeries programs.