BASIC RATE ISDN WORKSTATION TRAFFIC PATTERNS

At present, the PC class of machine equipped with a modem and connected to the public switched telephone network (PSTN) finds many applications; access to electronic mail services, access to office computers by home-workers, occasional access to a mainframe from an isolated office, etc. Two developments are coinciding which will affect this usage; PCs are being upgraded into much more sophisticated workstations, and the PSTN is to be replaced by the integrated services digital network (ISDN), a digital service offering much greater bandwidth. These developments will have a significant effect on the ways in which isolated machines are used. Some results are presented from an assessment made at University College London on the extent to which modes of usage currently prevalent on LANs might translate to the ISDN workstation. Measurements have been made of traffic on a LAN, and extrapolations have been made to gauge the effects of interposing ISDN both on performance and on cost.