Stratified reference model an open architecture approach for B-ISDN

For the past one or two decades, the global digital telecommunication environment has become more and more complex. The need for conceptual tools, to keep items related to the design, the evolution; the description, the planning and the analysis of the network within manageable complexity limits, has thus steadily increased. Currently, this need is even more accentuated since the bases of B-ISDN are in the melting-pot.