Analysis and Simulation of a Traffic Management Control Scheme for Atm Switches with Loose Commitments

This paper presents a heuristic approach to the problem of call admission control. The algorithm is based on traffic measurements and does not guarantee bounded delays or cell losses. It features very low cell delay variation tolerance for CBR traffic and is aware of negotiated, but unused, bandwidth from users. The algorithm does not assume any traffic models for the calls, so composed traffic models for call admission control cannot be used either. Such algorithms have to be tested by simulation. We simulated several specific controversial cases using real pattern traffic (CBR, real MPEG films, and typical IP traffic). Different offered loads (per simulation and during the same simulations) were used. The algorithm proved to deliver the same results as the theoretical approaches (in respect to average cell delay) but with much higher network utilization. It proved to manage well very “ill-behaved” calls in terms of burstiness and grain size.