1. A system for modeling and simulating a network including a plurality of nodes comprising: a processing system to model and simulate said network, said processing system including: a node model generation unit to produce a node model defining a reconfigurable network node to enable said processing system to simulate different configurations of said network node, wherein said node model includes a communications protocol stack with a plurality of protocol layers each including one or more individually selectable function modules for performing communications protocol layer functions, and at least one selectively configurable module switch each disposed between adjacent ones of said protocol layers to selectively couple said function modules of said adjacent protocol layers, wherein each of said function modules of said protocol layers are selectable by a corresponding configurable module switch and at least one protocol layer includes a plurality of said individually selectable function modules, wherein said at least one configurable module switch is dynamically configured during said simulation based on one or more simulation settings and controls said coupling of said function modules to configure said node for a desired behavior during said simulation, and wherein said one or more simulation settings are modifiable by a user and said modifiable simulation settings override a previous node configuration.