Nortel Networks Corporation

Daniel A Simone

Derek H Pitcher

Kishore K Seshadri

A method and apparatus for performing per-port Internet Protocol (IP) multicast pruning, proxying of IP multicast group membership reports, and generating pseudo membership queries for determining IP multicast group membership are provided. A switch may implement per-port IP multicast pruning by establishing a mapping of IP multicast groups to its ports. The mapping is based upon membership reports received from each end-station participating in an IP multicast group. Based upon the mapping, the switch forwards IP multicast packets only to those of the end-stations that are participating in the IP multicast group addressed. Once per-port IP multicast pruning is implemented, multicast routers must process membership reports from all end-stations participating in an IP multicast group. To reduce this burden, a switch may act as a proxy device. The switch receives a membership report identifying an IP multicast group. If the membership report is the first received for the IP multicast group after a membership query, then the switch forwards the membership report. However, if the membership report is not the first received, then the switch discards the membership report. To allow IP multicast group membership determination when no querier is present, a switch determines if another device is currently acting as a querier for a switched network. If not, the switch sends a membership query on one or more of its ports. Responsive to the membership query, an end-station transmits a membership report to the switch. The switch records the IP multicast group membership indicated in the membership report.

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Mountain View, CA, United States of America

Daniel A Simone