Welcome to the fourth IFIP workshop on prools for high speed networks in Vancouver. This workshop follows three very successful workshops held in Ziirich (1989), Palo Alto (1990) and Skholm (1993) respectively. We received a large number of papers in response to our call for contributions. This year, forty papers were received of which sixteen were presented as full papers and four were presented as poster papers. Although we received many excellent papers the program committee decided to keep the number of full presentations low in order to accommodate more discussion in keeping with the format of a workshop. Many people have contributed to the success of this workshop including the members of the program committee who, with the additional reviewers, helped make the selection of the papers. We are thankful to all the authors of the papers that were submitted. We also thank several organizations which have contributed financially to this workshop, specially NSERC, ASI, CICSR, UBC, MPR Teltech and Newbridge Networks.