Performance Evaluation of a Variable Frame Multiplexer for Integrated Switched Networks

A scheme which multiplexes long messages and single packets using a time-varying frame is presented. Long messages, generated from a fixed number of terminals, immediately access a main trunk, sharing a dynamically dedicated subchannel in a roundrobin fashion. Fixed size packets arrive with Poisson statistics in a FIFO queue and are served through the same trunk, using the remaining capacity. The two traffic categories share an integrated variable length frame. The frame length is determined by the volume of the increasing traffic at the beginning of the frame and cannot exceed a maximum value. Analysis of the performance of the system is carried out using finite population round-robin processor sharing and queueing techniques. Simplifying modeling assumptions are checked with simulation. A comparison with fixed frame schemes demonstrates the superiority of the variable frame, in terms of more efficient bandwidth utilization.