It is a challenging issue to provide guaranteed QoS for diverse network applications while still obtaining high network utilization in Difserv networks. As a promising approach to achieve the tradeoff between network utilization and the provision of QoS, the concept of effective bandwidths has been widely accepted. We propose a traflc measurement-based adaptive effective bandwidth allocation algorithm aiming at overcoming the conservative nature of effective bandwidths. We study the performance of adaptive effective bandwidth allocation under dynamic weighted round robin scheduling instead of a FIFO queueing discipline, aiming at providing dflerentiated services to trafic flows. We quantify the statistical multiplexing gain among multiple traflc classes with a set ofsimulations.