Modeling the application layer structure

The OSI application layer is considerably more complex in its structure than the protocols of other layers. To ensure proper and modular development of the layer, appropriate software models are essential. This paper examines two models: a functional model and an object-oriented model, which are capable of achieving the objective. The design architecture and strength of each model are presented. By and large, the functional model offers the advantage of easy integration in functional application developments, whereas an object-oriented model facilitates object-oriented application developments. A wide spectrum of specific communication services could be built with either model to meet various applications´ communication requirements in a modular and manageable manner