PERFORMANCE ANALYSIS OF BACKPRESSURE CONGESTION CONTROL - PRELIMINARYCASE

In ATM networks, preventive control is widely recognized as a way to a void congestion efficiently. It Is implemented by a conjunction of cal l admission control (CAC) and usage parameter control (UPC). However, since congestion may still happen because of unpredictable statistical fluctuation of traffic injected into networks, it would be effective to relieve congestion using reactive control together with a preventiv e measure. In this paper, the performance of backpressure control, whi ch is a reactive approach with an analytical approach, is investigated . Moreover, backpressure control with cell pushout scheme is proposed as a way to overcome some backpressure control weaknesses. It is gener ally pointed our that if congestion perseveres, congestion can prevail over a wide range of network. This is because the backpressure affect s even the traffic that does not go through congested nodes. By applyi ng a cell pushout scheme to the buffer of the nodes where traffic stop ped, the performance of backpressure control will be improved. Numeric al results show that the control with push-out scheme improves cell lo ss performance without little increase in delay.