Patent ID: 8208418

Claim:
A method for conserving multicast ports list resources, the method comprising: at an Internet protocol (IP) packet forwarding device: storing, in first memory of the IP packet forwarding device, an IP multicast packet port data structure containing at least a first port list and a second port list, the first and second port lists each containing zero or more port identifiers for indicating the ports to which a received IP multicast packet including a group IP address is to be forwarded; populating the IP multicast port data structure using Internet group management protocol (IGMP) snooping; storing, in second memory of the packet forwarding device separate from the first memory, an IP multicast packet forwarding database (FDB) having at least a first FDB entry and a second FDB entry for forwarding the received IP multicast packet based on its group IP address, the first and second FDB entries each including at least one multicast group IP address and being associated with at least one of the first and the second port lists; determining whether the first and second port lists contain identical information; in response to determining that the first and second port lists contain identical information, associating the first and second FDB entries with the first port list and releasing hardware resources associated with the second port list; and forwarding a first packet by performing a lookup in the IP multicast forwarding database, locating a matching entry in the IP multicast forwarding database, obtaining a pointer to an entry in the IP multicast port data structure, and multicasting the first packet to ports obtained from the entry in the IP multicast port data structure.