Due to the drastic technological innovation and introduction of various kinds, of new communication services, the structure and operation of communication networks are becoming complicated and diversified more and more. Accordingly, the necessity of flexible simulation tools which can be utilized for various performance evaluation jobs in various types of communication networks is growing. In this article, various existing simulation tools are briefly surveyed and the requirements for the simulator dedicated for the performance evaluation of communication networks are discussed. Then, a strategy to develop a simulator dedicated for the performance evaluation of communication networks is proposed. Our approach is based on the prototyping strategy, in which a relatively simple prototype structure is developed first and more functions are added whenever necessary. By following this strategy, a simulator can be developed and evolved in a timely manner at a relatively small cost.