AppServers connected to one another
AppServer agents can connect as 4GL clients to other AppServers. Figure 3–7 shows three AppServer machines (in Windows and two UNIX) and one client application connected in an n-tier fashion.
AppServer-1 on the Windows machine accepts remote requests from the initial client application. AppServer-2 on UNIX accepts remote requests from AppServer-1, and AppServer-3 on UNIX accepts requests from AppServer-2.
Note that there is a separate AppServer session within each AppServer agent and the connection that an AppServer agent establishes with another AppServer is part of its AppServer session. That is, a connection that an AppServer agent establishes with another AppServer is part of its session context and is not shared with any other AppServer agent. For example, each AppServer agent running on AppServer-2 establishes and manages, as client, its own unique connection to AppServer-3.