A system for selecting options for modifying a network architecture in accordance with user preferences using a knowledge base and a database. The knowledge base includes rules to select modification categories and the database includes information on a plurality of equipment and a plurality of tariffs. To select the options, the system generates a base-line simulation from the network architecture, which base-line simulation includes performance data on the network architecture under a predetermined scenario. Modification categories based on the user preferences are selected using rules in the knowledge base, and equipment information and tariff information corresponding to the network modification categories are selected from the database to create modification options for the network modification categories. The modification options are evaluated using rules in the knowledge base. The system then generates a plurality of new simulations of the network architecture as modified by the modification options, and compares the performance data of the base-line simulation with performance data of the new simulations to specify differences in performance data between the base-line simulation and each new simulation. Finally, the modification options (each corresponding to one of the new simulations) are ranked using the specified differences in performance data between the base-line simulation and each new simulation, user preferences, and rules of the knowledge base.