Patent ID: 7480295

Claim:
A multicast service providing method, which is implemented in an Ethernet passive optical network where a plurality of optical network unit systems are connected centering on an optical line terminal system, the method comprising: (a) an optical network unit system monitoring a multicast protocol report message transmitted from a subscriber and creating a first Layer 2 (L2) multicast forwarding table; (b) an optical line terminal system monitoring the multicast protocol report message and creating a Layer 3 (L3) multicast forwarding table; (c) the optical line terminal system receiving a multicast address and optical network unit identifier information from the optical network unit system and creating a second L2 multicast forwarding table in a PON (Passive Optical Network) port; (d) if a multicast server transmits a multicast packet using a multicast address which the subscriber has registered, the optical line terminal system transmitting the multicast packet to a predetermined port using the L3 multicast forwarding table, searching for optical network unit systems of the plurality of optical network unit systems belonging to a corresponding multicast group using the created second L2 multicast forwarding table if the port to which the multicast packet should be transmitted is a PON port, and transmitting the multicast packet to the searched optical network unit systems; and (e) the optical network unit system which has received the multicast packet, transmitting the multicast packet to subscribers belonging to the corresponding multicast group using the first L2 forwarding table.