Method and apparatus for multicast packet readout control

• US 20050207417A1
• Filed: 12/28/2004
• Published: 09/22/2005
• Est. Priority Date: 03/19/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Matsuo, Tamotsu, Urano, Hiroshi, Ogawa, Masayuki, Miura, Kenji
• Granted Patent: US 7,912,054 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/522 Dynamic queue service slot or variable bandwidth allocation
• CPC Class Codes: H04L 47/621 Individual queue per connection or flow, e.g. per VC
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 47/6225 Fixed service order, e.g. Round Robin
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling

Abstract

A multicast packet readout control method is disclosed. An input multicast packet is temporarily stored in a multicast queue of a packet buffer. The multicast packet is read from the multicast queue, and converted into a unicast packet addressed to each of the destinations of the multicast packet. The converted unicast packet is stored in a unicast queue of the packet buffer. The converted unicast packet is then read from the unicast queue and transmitted to the destination.

Claims

1. A multicast packet readout control method comprising the steps of:

temporarily storing an input multicast packet in a multicast queue of a packet buffer;

reading the multicast packet from the multicast queue;

converting the multicast packet to a unicast packet addressed to each of destinations of the multicast packet;

storing the converted unicast packet in a unicast queue of the packet buffer; and

reading the converted unicast packet from the unicast queue and transmitting the unicast packet to the destination.

2. The method of claim 1, wherein a portion or the entirety of the multicast packet is read from the multicast queue of the packet buffer in time gap between unicast packet reading periods.

3. The method of claim 1, further comprising the steps of:

monitoring occupancy of the multicast queue of the packet buffer; and

discarding a newly input multicast packet of a primary signal, without storing the new multicast packet in a primary signal queue buffer, if the occupancy of the multicast queue exceeds a prescribed level.

4. A multicast packet readout control apparatus comprising:

a packet buffer configured to temporarily store an input multicast packet in a multicast queue;

packet conversion means configured to read the multicast packet from the multicast queue and convert the multicast packet to a unicast packet addressed to each of destinations of the multicast packet, the converted unicast packet being stored in a unicast queue of the packet buffer; and

reading and transmitting means configured to read the converted unicast packet from the unicast queue and transmit the converted unicast packet to the destination.

5. The apparatus of claim 4, wherein the packet conversion means is configured to read the multicast packet from the multicast queue in time gap between unicast packet reading periods.

6. The apparatus of claim 4, wherein the packet conversion means is configured to convert a priority class of the multicast packet into a priority class of the unicast packet.

7. The apparatus of claim 4, further comprising:

a primary signal queue buffer configured to store the input multicast packet of a primary signal before the input multicast packet is stored in the packet buffer;

a multicast temporary buffer configured to store the multicast packet read from the multicast queue; and

a selector configured to output either one of the multicast packet from the multicast temporary buffer and the input multicast packet of the primary signal from the primary signal queue buffer.

8. The apparatus of claim 7, further comprising:

a queue occupancy monitoring unit configured to receive monitor occupancy of the multicast queue and discard the multicast packet output from the selector when the monitored occupancy exceeds a prescribed level.

9. The apparatus of claim 8, wherein the queue occupancy monitoring unit is configured to instructs the primary signal queue buffer to discard the newly input multicast packet when the monitored occupancy exceeds the prescribed level.