An Integrated Switching Strategy for ABR Traffic Control in ATM Networks

In this paper we extend earlier results on combined control problem of connection admission, flow rate, and bandwidth allocation (capacity, service-rate) in ATM based networks under nonstationary conditions to the multiple node path case. We propose a nonlinear switching strategy, and show that it is effective in controlling a mix of ABR and Guaranteed traffic. We derive bounds on the mix between ABR and Guaranteed traffic to ensure that control strategy is effective. The derived strategy is insensitive to propagation delay along the path, and via the setting of the values of the control design variables it can be used to influence the delivered Quality of Service (QoS). The performance of proposed scheme is evaluated using analysis and simulation. Simulation results show that the proposed scheme achieves effective server and buffer utilisation (as predicted by analysis) and achieves prescribed bounded delays (for Guaranteed traffic only) and zero cell loss (even for ABR traffic demands exceeding server capacity, which if not controlled would cause cell loss). Thus proposed scheme delivers guaranteed QoS to user, avoids retransmissions, and as a result increases network utilisation and customer satisfaction. 1