Abstract: A node model of the present invention is employed by a network modeling and simulation system and includes a communication protocol stack with a plurality of protocol layers. Each protocol layer includes communication functions. The protocol layer functions are each represented by one or more distinct software implementations that are optimized for different simulation purposes. A configurable module switch is disposed between protocol layers within the stack to selectively control information flow between functions within adjacent protocol layers. The node model enables a user to perform network simulation or analysis of varying detail or granularity.