The Research Experience for Undergraduates program was formed by the National Science Foundation to provide opportunities for undergraduates to perform research under the guidance of established researchers. It is hoped that they will find the experience rewarding, and will be attracted to careers in research. Two types of awards are supported: site grants, and supplements to existing research awards. This is a site grant, in which Tulane University will team eight undergraduate students with two faculty members to investigate the expansion of Petri net modeling capability and its application to computer networks. Five students will work during the 1989 summer at Tulane, and three will work at Bell Northern Research. All will work together at Tulane during the following academic school year.