A Simulation Environment for Hierarchical Process Chains Based on OMNeT++

OMNeT++ is a discrete event simulation environment primarily designed for communication networks. In this paper we present an approach to enable OMNeT++ to simulate complex hierarchical process chains. Process chains are a common modeling paradigm in the logistics area for the analysis and optimization of large process chains and have been intensely used in many practical applications. Their evaluation is supported by the ProC/B toolset, a collection of software tools for modeling, analysis, validation and optimization of process chains. Here we describe how OMNeT++ has been integrated as a new simulation engine into the toolset. The integration has to get over some core problems to allow a smooth interaction between OMNeT++ and the other tools: In particular, the OMNeT++ model description of the logistics network should be kept manageable, it should reflect the entire model structure and non-standard performance figures, being relevant for an economic evaluation, should be ascertainable in order to satisfy the specific needs of the application area. The paper highlights the main steps of the automatic transformation of a hierarchical process chain model into a hierarchical model in OMNeT++. Furthermore, we show how the transformation has been validated and how detailed performance figures can be evaluated with OMNeT++.