Ethernet-based passive optical network (EPON) technology is being considered as a promising solution for next generation broadband access networks due to the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure along with its ability to support successfully IP-based multimedia applications with quality of service requirements. We propose to use the multi-point control protocol (MPCP) defined in the IEEE 802.3ah task force to arbitrate the transmission of different users; dynamic bandwidth allocation (DBA) algorithms are then presented to allocate bandwidths between these users effectively and fairly. These DBA algorithms are then augmented to support differentiated services in a network with heterogeneous traffic. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed protocols.