Methods and apparatus for the fair allocation of bandwidth among MCR and best effort service connections in an ATM switch
First Claim
1. A method for allocating bandwidth among MCR connections and best effort connections in an ATM switch, said method comprising:
- a) associating each MCR connection with an individual queue;
b) associating each queue with a cell count register and a MCR register;
c) setting the values of the MCR registers based on guaranteed bandwidth of all the MCR connections and the presently available bandwidth of the associated port in the switch;
d) setting the values of each cell count register based on its associated MCR register value;
e) listing all of the MCR connection queues in an MCR service list;
f) dequeuing cells from the MCR connection queues in a round robin fashion according to the MCR service list during a service interval;
g) decrementing cell count registers as associated queues are dequeued; and
h) removing MCR connection queues from the MCR service list when the queues become empty or the cell count register for the queue goes to zero during the service interval whichever occurs first.
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Accused Products
Abstract
Methods for allocating bandwidth among MCR and best effort connections include listing MCR connections in an MCR service list and best efforts connection in a best efforts (BE) service list. Assigning an MCR value to each MCR connection and setting a Cell Count Register (CCR) with it. During a service interval, dequeueing each MCR connection queue in round robin fashion according to the MCR service list and decrementing the associated CCR. If the CCR reaches zero before the end of the service interval and there are still cells in the queue, the connection is moved from the MCR service list to the BE service list for the remainder of the service interval. If the CCR reaches zero before the end of the service interval and/or there are no cells remaining in the queue, the connection is removed from the MCR service list. If all of the cell counts reach zero and/or if all of the MCR queues become empty before the end of the service interval, the connections on the BE service list are serviced by a separate scheduler. At the end of the service interval, the CCRs are reinitialized and the MCR connections which were moved to the BE service list are moved back to the MCR service list.
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Citations
13 Claims
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1. A method for allocating bandwidth among MCR connections and best effort connections in an ATM switch, said method comprising:
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a) associating each MCR connection with an individual queue;
b) associating each queue with a cell count register and a MCR register;
c) setting the values of the MCR registers based on guaranteed bandwidth of all the MCR connections and the presently available bandwidth of the associated port in the switch;
d) setting the values of each cell count register based on its associated MCR register value;
e) listing all of the MCR connection queues in an MCR service list;
f) dequeuing cells from the MCR connection queues in a round robin fashion according to the MCR service list during a service interval;
g) decrementing cell count registers as associated queues are dequeued; and
h) removing MCR connection queues from the MCR service list when the queues become empty or the cell count register for the queue goes to zero during the service interval whichever occurs first. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for allocating bandwidth among MCR and best effort connections in an ATM switch, said apparatus comprising:
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a) a plurality of MCR queues, one for each active MCR connection;
b) a plurality of cell count register, one for each MCR queue;
c) a plurality of MCR registers, one for each MCR queue;
d) an MCR scheduler coupled to said queues and said registers;
e) an MCR service list coupled to said MCR scheduler, wherein said MCR scheduler sets the values of the MCR registers based on guaranteed bandwidth of all active MCR connections and presently available bandwidth in the switch, said MCR scheduler sets the values of each cell count register based on its associated MCR register value;
said MCR scheduler lists all of the MCR connection queues in the MCR service list;
said MCR scheduler dequeues cells from the MCR connection queues in a round robin fashion according to the MCR service list during a service interval;
said MCR scheduler decrements cell count registers as associated queues are dequeued; and
said MCR scheduler removes MCR connection queues from the MCR service list when the queue becomes empty or the cell count register for the queue goes to zero during the service interval whichever occurs first. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for allocating bandwidth among high priority connections and low priority connections in a packet switch, said method comprising:
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a) associating each high priority connection with an individual queue;
b) associating each queue with a packet count register and a minimum packet rate register;
c) setting the values of the minimum packet rate registers based on guaranteed bandwidth of all the high priority connections and the presently available bandwidth of the associated port in the switch;
d) setting the values of each packet count register based on its associated minimum packet rate register value;
e) listing all of the high priority connection queues in a high priority service list;
f) dequeuing packets from the high priority connection queues in a round robin fashion according to the high priority service list during a service interval;
g) decrementing packet count registers as associated queues are degueued; and
h) removing high priority connection queues from the high priority service list when the queues become empty or the packet count register for the queue goes to zero during the service interval whichever occurs first.
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Specification