Performance analysis of ISDN switching systems

The author discusses the impact of D-channel service mixtures on ISDN (integrated services digital network) switching system performance. The performance analysis is based on data link (layer 2) and network layer (layer 3) modeling, as well as switching system processing time. The aim of the modeling work is to quantify the impact of the service mixtures on the D-channel capacity and the ISDN performance objectives. The author addresses the layer 2 and 3 delays which are elements in the ISDN call establishment and D-channel packet data delay. For a specific configuration, he provides estimates of layer 2 and 3 delays in the absence of unsatisfactory deterioration in performance. Numerical results for various voice and packet data service mixtures are presented. When data packet rates increase, the basic call establishment delays increase as well. The increase in delays is not significant at packet data rates of less than or equal to 2 d.p.p.s. per BRA (basic rate access) line. For an increase of 1 d.p.p.s. per D-channel, the basic call establishment delays increase by less than 15%