The derivation of performance expressions for communication protocols from timed Petri net models

Petri Net models have been extended in a variety of ways and have been used to prove the correctness and evaluate the performance of communication protocols. Several extensions have been proposed to model time. This work uses a form of Timed Petri Nets and presents a technique for symbolically deriving expressions which describe system performance. Unlike past work on performance evaluation of Petri Nets which assumes a priori knowledge of specific time delays, the technique presented here applies to a wide range of time delays so long as the delays satisfy a set of timing constraints. The technique is demonstrated using a simple communication protocol

A Petri Net Tool for Software Performance Estimation Based on Upper Throughput Bounds

Functional and non-functional properties analysis (i.e., dependability, security, or performance) ensures that requirements are fulfilled during the design phase of software systems. However, the Unified Modelling Language (UML), standard de facto in industry for software systems modelling, is unsuitable for any kind of analysis but can be tailored for specific analysis purposes through profiling. For instance, the MARTE profile enables to annotate performance data within UML models that can be later transformed to formal models (e.g., Petri nets or Timed Automatas) for performance evaluation. A performance (or throughput) estimation in such models normally relies on a whole exploration of the state space, which becomes unfeasible for large systems. To overcome this issue upper throughput bounds are computed, which provide an approximation to the real system throughput with a good complexity-accuracy trade-off. This paper introduces a tool, named PeabraiN, that estimates the performance of software systems via their UML models. To do so, UML models are transformed to Petri nets where performance is estimated based on upper throughput bounds computation. PeabraiN also allows to compute other features on Petri nets, such as the computation of upper and lower marking place bounds, and to simulate using an approximate (continuous) method. We show the applicability of PeabraiN by evaluating the performance of a building closed circuit TV system

Aplicación De Redes De Petri A La Evaluación De Desempeño De Sistemas De Comunicaciones

Performance evaluation of communications systems is usually done by analytical techniques or simulation. The analytical approach is normally based on a probabilistic description of the system operations in terms of Markovian processes or queuing systems, but only is directly applicable for simple systems, or simplistic models of complex systems. Simulation is a powerful tool but requires enormous computations to yield accurate performance estimators. In this paper we present an alternative technique: Petri Nets, a graphical and mathematical modeling tool applicable to many systems. We used Stochastic Petri Nets to model and evaluate queuing systems and some protocols. Simple and accurate models were developed. The main definitions relating Petri nets in general, and to the particular classes of Petri nets are summarized in Section 1. The following sections contains queuing models (Section2 ), Stop and Wait and Aloha protocols (Section 3), DSP protocol (Section 4). Section 5 concludes the paper