US 6,836,480 B2Granted

Data structures for efficient processing of multicast transmissions

AssigneeInternational Business Machines Corporation

InventorsClaude Basso, Jean Louis Calvignac, Marco C. Heddes, Joseph Franklin Logan, Fabrice Jean Verplanken

Life of this patent

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Abstract

Data structures, a method, and an associated transmission system for multicast transmission on network processors in order both to minimize multicast transmission memory requirements and to account for port performance discrepancies. Frame data for multicast transmission on a network processor is read into buffers to which are associated various control structures and a reference frame. The reference frame and the associated control structures permit multicast targets to be serviced without creating multiple copies of the frame. Furthermore this same reference frame and control structures allow buffers allocated for each multicast target to be returned to the free buffer queue without waiting until all multicast transmissions are complete.

Claims12

Dependent claims

A method of multicast transmission on a network processor comprising the steps of:

storing the frame to be transmitted in a series of buffers, chained together by a linked list;
associating a buffer control block with each buffer;
associating a frame control block with each frame;
receiving frames into a queue to await dispatch by a network processor;
associating a queue control block with the queue of frames to be transmitted;
assigning additional buffers and additional frame control blocks for each multicast target and linking these additional frame control blocks with the original frame control block associated with the frame;
using a multicast counter to determine when the frame has been sent to each of the multicast targets;
returning the buffers and frame control blocks assigned to each multicast target to free queues as the frame is sent to each target;
and
returning the original buffers and frame control blocks to the free queues after the frame has been sent to all of the multicast targets.

7 more elements

A network processor supporting multicast transmission comprising:

means for storing a frame to be transmitted in a series of buffers, chained together by a linked list;
means for associating a buffer control block with each buffer and associating a frame control block with each frame;
means for receiving frames into a queue to await dispatch;
means for associating a queue control block with the queue of frames to be transmitted;
means for assigning additional buffers and additional frame control blocks for each multicast target and linking these additional frame control blocks with the original frame control block associated with the frame;
means using a multicast counter for determining when the frame has been sent to each of the multicast targets;
and
means returning the buffers and frame control blocks assigned to each multicast target to free queues as the frame is sent to each target and returning the original buffers and frame control blocks to the free queues after the frame has been sent to all of the multicast targets.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/839,079Filed 20 Apr 2001
Published: US 2002/0154634 A124 Oct 2002
Granted: 28 Dec 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04L 49/901
Buffering arrangements: using storage descriptor, e.g. read or write pointers
H04L 12/1881
For broadcast or conference , e.g. multicast: with schedule organisation, e.g. priority, sequence management
H04L 47/10
Traffic control in data switching networks: flow control; Congestion control
H04L 47/20
Flow control; Congestion control: traffic policing