You can choose to build a PAS for OpenEdge application that runs in one of the two application models, session-managed or session-free. You can also build an application that runs in a combination of the two models, where a client can connect using one model or the other, depending on the application features that the client needs to access on a PAS for OpenEdge instance.

In addition, the session-managed model supports two connection states, bound and unbound, that are determined by your PAS for OpenEdge application at run time. The session-free model also provides support for bound connections, but PSC recommends that you avoid them. For information on how each application model affects the PAS for OpenEdge and client operation, see PAS for OpenEdge and Client Interaction