Patent ID: 7738490

Claim:
A method for fairly allocating a differentiated bandwidth based on shared multicast traffic in the transmission of downstream traffic in a Time Division Multiplexed-Passive Optical Network (TDM-PON), the method comprising the steps of: a) providing the TDM-PON comprised of a plurality of optical network units (ONUs) and an optical line terminal (OLT) for controlling downstream data transmission; b) deciding a total number of multicast groups to which services are currently provided, and a number of multicast groups to which a predetermined ONU subscribes by a multicast share management block of a timeslot allocation block of the OLT; c) calculating a multicast share degree in each of the multicast groups, and a total multicast share degree of the predetermined ONU in all of the multicast groups by the multicast share management block; d) dividing the total multicast share degree of the predetermined ONU by the total number of multicast groups to calculate a final normalized multicast share degree of the predetermined ONU by the multicast share management block; e) calculating an average multicast bandwidth of the predetermined ONU depending on a total bandwidth allocated to multicast traffic services on the basis of the final normalized multicast share degree by a timeslot arbitration block of the timeslot allocation block of the OLT; f) calculating a differentiated bandwidth of the predetermined ONU using ONU-specific service weights by the timeslot arbitration block; and g) subtracting the average multicast bandwidth from the differentiated bandwidth of the predetermined ONU to calculate a maximum dynamic timeslot bandwidth of the predetermined ONU by the timeslot arbitration block.