Performance objectives for ISDN´s

THE CONCEPT OF the Integrated Services Digital Network (ISDN) and various aspects of its implementation concerning transmission, switching, subscriber interface and signaling are first briefly reviewed. Approaches to the specification of ISDN performance, currently under consideration of the International Telegraph and Telephone Consultative Committee (CCITT) for standardization, are described. A new parameter, percentage Error-Free Blocks (EFB´s), is suggested as an additional measure to be specified at different block lengths. The need for more realistic consideration of the impact of burst errors is highlighted and a procedure is outlined using a specific channel model. Also discussed is the effect of delay when satellite channels are revolved. It is suggested that a joint EFB-delay constraint specification might be useful for network routing internal to ISDN.