| US 7,532,624 B2 | ||
| Multicast packet control apparatus | ||
| Kozo Ikegami, Yokohama (Japan); Takashi Yokoyama, Yokohama (Japan); Minoru Nagai, Fujisawa (Japan); Yoshitaka Sakamoto, Yokohama (Japan); and Shigehiro Onizawa, Yokohama (Japan) | ||
| Assigned to Hitachi Communication Technologies, Ltd, Tokyo (Japan) | ||
| Filed on Aug. 23, 2006, as Appl. No. 11/508,240. | ||
| Claims priority of application No. 2006-006029 (JP), filed on Jan. 13, 2006. | ||
| Prior Publication US 2007/0165633 A1, Jul. 19, 2007 | ||
| Int. Cl. H04L 12/28 (2006.01) | ||
| U.S. Cl. 370—390 [370/395.42; 370/432; 370/468] | 10 Claims |
| 1. A multicast packet control apparatus for relaying packets between a plurality of user terminals and a packet transfer apparatus
in a network system where multicast communication is performed by a point-to-point connection between the user terminals and
the packet transfer apparatus, the multicast packet control apparatus comprising:
a multicast transmission buffer for storing packets used in multicast communication;
a transfer limitation table for storing transfer rate limitation information corresponding to the utilization rate of the
multicast transmission buffer, and for limiting transfer from the multicast transmission buffer to the packet transfer apparatus;
a discard table for storing a group address and a transmission-source address, and for recording a discarded packet; and
a processor for controlling packet transfer by referencing and updating the transfer limitation table and the discard table,
wherein
the processor transfers a received packet to the multicast transmission buffer when the received packet is determined to be
a response packet corresponding to join confirmation from the packet transfer apparatus;
the processor monitors the utilization rate of the multicast transmission buffer, compares the monitored utilization rate
with the utilization rate of the multicast transmission buffer specified in the transfer limitation table when the response
packet is transferred to the multicast transmission buffer, obtains corresponding transfer rate limitation information, and
limits the transfer rate or the number of packets transferred from the multicast transmission buffer to the packet transfer
apparatus in accordance with the transfer rate limitation information if a limitation is needed;
the processor searches through the discard table if the response packet is received while the limitation is imposed;
the processor discards the received packet if the discard table contains no data item corresponding to the group address and
the transmission-source address of the received packet, and records the group address and the transmission-source address
in the discard table; and
the processor stores the received packet in the multicast transmission buffer with priority if the discard table contains
data items corresponding to the group address and the transmission-source address of the received packet, and deletes the
data items corresponding to the group address and the transmission-source address from the discard table.
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