ATM switch which counts multicast cell copies and uses a second memory for a decremented cell count value
AssigneeNortel Networks Limited
InventorsStacy W. Nichols, David A. Brown, David G. Stuart
Life of this patent
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Abstract
In a multicast cell counting methodology, the use of banked memories for enqueuing and dequeuing a multicast cell count value spreads the memory accesses over multiple memories, yielding a reduction in the number of per memory accesses per cell cycle. A cell count value, representing the number of cell copies to be multicast, is written to a first memory on a cell enqueue, and retrieved from the first memory after a first cell dequeue. The cell count value is decremented to reflect the first cell dequeue, and transferred to a second memory.
Claims13
A method for counting multicast cell copies in a switch in an ATM network, the switch having two multicast cell count memories, the method comprising the steps of:
- writing a cell count value to a first memory on a cell enqueue;
- retrieving the cell count value from the first memory after a first cell dequeue;
- decrementing the cell count value to reflect the first cell dequeue;
- and
- transferring the decremented cell count value to a second memory.
A system for counting multicast cell copies in a switch in an ATM network, the switch having two multicast cell count memories, the system comprising:
- means for writing a cell count value to a first memory on a cell enqueue;
- means for retrieving the cell count value from the first memory after a first cell dequeue;
- means for decrementing the cell count value to reflect the first cell dequeue;
- and
- means for transferring the decremented cell count value to a second memory.
A communications network comprising:
- a plurality of nodes sending and receiving cells;
- and
- a switch interconnecting the nodes, the switch including
- means for writing a cell count value to a first memory on a cell enqueue;
- means for retrieving the cell count value from the first memory after a first cell dequeue;
- means for decrementing the cell count value to reflect the first cell dequeue;
- and
- means for transferring the decremented cell count value to a second memory.
Dependencies are inferred from the claim text.