The effects of AQM on the performance of assured forwarding services

Several active queue management (AQM) mechanisms have been proposed in the literature to provide better support for congestion. However, their performance is examined mainly in best-effort networks. In this paper, we present an empirical study of the effects of these AQM mechanisms on the performance of Assured Forwarding (AF) Services in the Differentiated Services (DiffServ) framework. In addition, we investigate the interaction of AQMs with intelligent traffic conditioners. The major conclusions from our study are: (1) When the standard traffic conditioner is used, the transient response and the ability of controlling queue length of an AQM scheme not only affect the achievement of bandwidth assurance, but also affect the attainment of excessive bandwidth and link throughput. (2) The behaviors of an AQM affect the ability of intelligent traffic conditioners. (3) Rate-based AQM schemes perform better than queue-based AQM schemes; self-tuning AQM schemes perform better than AQMs with fixed-gains in terms of the above performance metrics.