Abstract: A network simulator for use as a testing tool for a network management system includes an input device for inputting data containing network elements, their attributes, and information about their configuration, for storage in memory. User-defined scenario instructions for specifying particular network behavior and user directives are input in real time, or in advance of simulation. The simulator includes an input/output processing component that receives commands from the network management system and user-scenario data or directives and forwards received commands and directives to a response generator processing component that generates appropriate responses in accordance with the network element behavior data stored in memory. The response generator processing component transmits responses back to the network management system.