A client application logically connects to an application service supported by one or more AppServer instances, as shown in the following figure. The dotted arrows indicate paths of communications required for multiple AppServer instances to service multiple client requests for the same application service. The NameServer is also an optional component for managing session-free connections. As long as there are enough AppServer agents and computing power to run them, a single AppServer can still scale up for higher client loads. However, if you have multiple AppServer instances supporting an application service, you lose the benefits afforded by load balancing, which is available using the NameServer.
Figure 10. Logical connection model
OpenEdge supports logical connections for ABL and Web service clients only. As shown in the above figure, note that for an ABL client, OpenEdge manages all access to AppServer resources from within the client session.
