International Jl. of Educational Telecommunications (2001) 7 (2), 157-194 Towards a Telecommunication Platform for Supporting Distributed Virtual Laboratories SAMUEL PIERRE AND MARTHE KASSOUF Mobile Computing and Networking Research Laboratory Department of Electrical and Computer Engineering cole Polytechnique de MontrØal C.P. 6079, Succ. Centre-Ville MontrØal, QuØbec, Canada, H3C 3A7 samuel.pierre@polymtl.ca This article presents a telecommunication platform dedicated to supporting distributed virtual laboratories. The architec- ture of this platform is made of three layers. The first layer deals with interoperability among heterogeneous networks and allows users to access virtual laboratory environments. The second layer provides a set of tools and generic func- tionalities sharable among several specific laboratories. The third layer insures the adaptation of these basic tools to other specific tools that exist in the peculiar context of each labo- ratory. The result is a distributed environment in which di- verse elements interoperate to provide not only for pedagogi- cal contents but also access mechanisms to simulations and virtual experimentation from different specific laboratories. The experimentation results put the network congestion level and the quality of service required by the user on top of the criteria determining the global efficiency of this platform. The more computer networks evolve, the more the variety of machines related to them and the links they use increase. In fact, each type of net- work has its own specific logical setting, mode of switching, data format, and level of quality of service. This explains, in part, the existence of heter- ogeneous environments for public and private networks of boundless