Real-Time Distributed Systems Dimensioning and Validation: The TURTLE Method

The TURTLE language and toolkit offer a UML framework for service description, protocol modeling and communication architecture validation. The method associated with TURTLE uses an architectural design pattern where two or several protocol entities rely on a pre-existing communication service. Modeling the pre-existing service with empirical values is error-prone and hampers large space exploration during the communication architecture validation. The paper relies on the Network Calculus theory to parameterizes the service with realistic upper bounds. The revisited TURTLE method includes a dimensioning step between the requirement and analysis steps. This new step is based on a "Dimensioning Diagram" that describes the network in terms of traffic and equipments behavior, and a "Dimensioning-oriented Use Case Diagram" that categorizes the flows conveyed by the network. The paper applies this method to a video conference system as example.