A FLEXIBLE GRAPHICAL USER-INTERFACE FOR PERFORMANCE MODELING

We identify three goals for the graphical user interface (GUI) of a ne twork simulation environment: user friendliness, model re-usability, a nd application extensibility. We address the user-friendliness issue b y proposing a simple yet efficient approach to setup parameters for th e simulation models. We address the application extensibility issue wi th a two-layer GUI architecture. The two layers are loosely coupled, a nd the first layer can be easily replaced without affecting the other components of the simulation environment. The concept of subnetwork is used to address the model reusability issue. Unlike most existing sim ulation packages, where a subnetwork is simply a method to group the n odes, the subnetwork construct in our approach is a first-class citize n in the simulation environment (i.e., all operations for a basic node also apply to a subnetwork). The port concept is used to define the I /O relationship between a subnetwork and the outside world. Parameter dialog boxes are used to set up the parameters for a subnetwork conven iently. Finally, a simple stack mechanism is used to measure subnetwor k-wide output statistics.