US 5,359,592 AGranted

Bandwidth and congestion control for queue channels in a cell switching communication controller

AssigneeStratacom, Inc.

InventorsCharles M. Corbalis, Ross S. Heitkamp, Rafael Gomez

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Abstract

A mechanism for buffering communication cells in a communication controller, wherein a cell queuing circuit provides a cell loss priority mechanism, and wherein the cell queuing circuit determines service states for queue channels according to bandwidth allocation parameters. The service states includes a serve.sub.-- now state, a serve.sub.-- ok state, and a no.sub.-- serve state, such that a queue channel is in the serve.sub.-- now state if the queue channel must be serviced to maintain a minimum information rate parameter for the queue channel, the serve.sub.-- ok state if the queue channel can be serviced and not exceed a peak information rate parameter for the queue channel.

Claims28

Dependent claims

A method for buffering communication cells in a plurality of queue channels in a communication controller, comprising the steps of:

receiving a first communication cell over a first communication link, the first communication cell specifying a destination queue channel from among a plurality of queue channels, the first communication cell comprising a cell loss priority status;
if the cell loss priority status is in a first state and if a depth of a destination cell queue corresponding to the destination queue channel exceeds a cell loss priority threshold for the destination queue channel, then discarding the first communication cell;
if the cell loss priority status is not in the first state or if the depth of the destination cell queue corresponding to the destination queue channel does not exceed the cell loss priority threshold, then entering the communication cell into the destination cell queue;
updating a set of queue service control parameters for each queue channel in a service chain while determining a next serviced queue channel in the service chain according to the queue service control parameters, the queue service control parameters specifying bandwidth allocation on a second communication link;
accessing a second communication cell from a serviced cell queue specified by the next serviced queue channel, and transferring the second communication cell over the second communication link.

2 more elements

An apparatus for buffering communication cells in a plurality of queue channels in a communication controller, comprising:

circuit for receiving a first communication cell over a first communication link, the first communication cell specifying a destination queue channel from among a plurality of queue channels, the first communication cell comprising a cell loss priority status;
circuit for discarding the first communication cell if the cell loss priority status is in a first state and if a depth of a destination cell queue corresponding to the destination queue channel exceeds a cell loss priority threshold for the destination queue channel;
circuit for entering the communication cell into the destination cell queue if the cell loss priority status is not in the first state or if the depth of the destination cell queue corresponding to the destination queue channel does not exceed the cell loss priority threshold;
circuit for updating a set of queue service control parameters for each queue channel in a service chain while determining a next serviced queue channel in the service chain according to the queue service control parameters, the queue service control parameters specifying bandwidth allocation on a second communication link;
circuit for accessing a second communication cell from a serviced cell queue specified by the next serviced queue channel, and transferring the second communication cell over the second communication link.

2 more elements

Dependencies are inferred from the claim text.