The SES Workbench
SES/Workbench1 is an integrated collection of software tools for the design and the performance evaluation of complex systems and particularly the telecommunication protocols and services. It is an object oriented system since it supports object types, methods instances and references.
A SES/workbench model is a hierarchy of submodels, where each submodel is represented by a directed graph. Submodels can call each other in the same way it is done in the classical languages (C, PASCAL, etc.) context.
The main components of SES/Workbench are:
- SES/design: a graphic interface module for specifying a system design.
- SES/simulation: a translation module for
converting the graphic design specification into an
executable simulation model
SES/Simulation: The behaviour of a SES/workbench model is modelled by flows of transactions. A transaction is represented as a separate thread of execution in the program.
To display an animated execution of the modelled system SES/Scope can be used. Hence an unexpected behaviour (functional and performance behaviours) of the model may be easily detected. The functional behaviour error (e.g. the receiver does not send the connect response when it receives the connect request) can be detected by the flow of transactions while the performance behaviour error (e.g. the delay to receive a connect request is zero) can be detected by the performance parameters values since we can display at run time different statistical values.
Performance statistics: The statistical output data may be processed by SES/graph to produce meaningful (simple) graphical representations. Hence one can display and plot statistical data produced during the model run .
After this short description of SES/workbench, we can confirm that SES/workbench supports the following characteristics:
- The time, the resources management and the probabilistic behaviour concepts.
- The parallelism and the concurrency notions.
- An object oriented approach. Hence it is easy to build, modify and parameterize (e.g. to extend) the modelled systems.
- The performance statistics can be collected at any point of the model.
Timed Interacting Systems (TIS)
TIS is a performance-enhanced FDT, based on process algebras and has many common concepts with LOTOS. Its operational semantics has been defined in [Wolisz91].
A TIS specification can be translated, using the SIMTIS library of node types, to an executable simulation model on SES/workbench.