US 6,160,812 A · Method and apparatus for supplying requests to a scheduler in an input buffered multiport switch

Abstract

A method and apparatus for supplying new requests to a scheduler in an input-buffered multiport switch involve selecting a request that does not target output channels that conflict with output channels targeted by requests that are already accessible to the scheduler. Specifically, target output channels of requests that are presently accessible to the scheduler are identified and compared to target output channels of requests that are included in a queue of next-in-line requests. The queue of next-in-line requests is reviewed and the highest priority request having no conflicting output channels is supplied to the scheduler. By supplying the scheduler with a new request that targets non-conflicting output channels, the scheduler is presented with a wider range of requested output channels from which to choose in each arbitration cycle. In a first embodiment, one, two, or eight ports are connected to each one of four input/output controllers in a switch having a four-channel switch fabric. To supply the scheduler with new requests, secondary arbitration is performed on a channel-specific basis in order to supply channel-specific requests to the scheduler. The method of supplying requests to the scheduler can be scaled to include multiple channels and multiple packet priority designations.

Claims20

Dependent claims

A method of supplying requests to a scheduler of a multiport switch having a plurality of outputs, said scheduler having access to a plurality of first output requests, said method comprising the steps of:

maintaining a queue of second output requests that are not accessible by said scheduler, each second output request being indicative of at least one target output;
determining which outputs are target outputs of said first output requests that are accessible by said scheduler;
selecting a highest priority request of said second output requests at least partially based on identifying a particular second output request for which indicated target outputs are mutually exclusive with said target outputs of said first output requests;
and
providing access of said highest priority request to said scheduler.

2 more elements

A method of supplying requests to a scheduler in a multiport switch that has a switch fabric with a plurality of switching channels and output ports associated with said switching channels comprising the steps of:

identifying output channels targeted by any first requests from a particular switching channel that are available to said scheduler for arbitration;
comparing said identified output channels to output channels that are targeted by second requests from said particular switching channel that are not available to said scheduler for arbitration;
and
making available to said scheduler a second request that does not target an output channel that is the same as one of said identified output channels targeted by any of said first requests, said second request being one of said second requests from said particular switching channel that are not available to said scheduler for arbitration before being made available to said scheduler.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for supplying requests to a scheduler in an input buffered multiport switch

Life of this patent

Method and apparatus for supplying requests to a scheduler in an input buffered multiport switch

Life of this patent

Abstract

Claims20