Modelling and simulation appear like an essential aspect to understand the specific behavior of Wireless Sensor Network (WSN). Zeigler in the 70 's introduces Discrete Event system Specification (DEVS) formalism. This formalism is able to describe the asynchronous nature of the events occuring in Wireless Sensor Network (WSN). In this paper we introduce a DEVS sensor model with a particular focus on network management. We decide to describe a routing protocol implemented in Berkeley sensors, MICA2 family, and to provide a simulation tool based on a discrete event approach. Our model use a detailled definition of node and is independant of operating system. It wants to bring some responses to understand the behavior of WSN at different level of abstraction. Simulation and analysis of results confirm utility, capacity and modular aspect of our model to represent a large number of nodes and specific characteristics of WSN.