Alcatel

Alcatel Internetworking, Inc.

Alcatel Lucent

Chris L Hoogenboom

John Daniel Wallner

Michael Jon Nishimura

Michael K Wilson

Todd Khacherian

An ATM switch with rate-limiting congestion control has a plurality of input ports, a plurality of output ports operatively associated with one or more data buffers, an output control and a switch fabric for switching data units from any of the input ports to any of the output ports on virtual connections. The ATM switch imposes and enforces transmission rate-limiting policies against the virtual connections when the backlog of data units for delivery to a particular output port reaches a particular level. The ATM switch may be arranged to exempt high priority data units from the imposed rate limitations and has a means to lift the rate limitations when the backlog has been sufficiently reduced.

ATM switch with rate-limiting congestion control

A digital traffic switch having DIBOC buffer control has a queue status-based control strategy to limit status traffic on the switch and status buffer requirements. Status messages are transmitted from inputs to outputs when the content status of a logical output queue has changed from 'empty' to 'not empty', or vice versa, rather than on a &#x201c;per cell&#x201d; request basis. Status messages are transmitted from outputs to inputs when the clearance status of a logical output queue has changed from &#x201c;not clear to release&#x201d; to &#x201c;clear to release&#x201d;, or vice versa, rather than on a &#x201c;per cell&#x201d; grant basis. The status of each logical output queue is monitored at outputs by retaining and updating a single status bit which has a particular binary value when the logical output queue's status is &#x201c;empty&#x201d; and the opposite binary value when the logical output queue's status is &#x201c;not empty&#x201d;. The status of each logical output queue is monitored at inputs by retaining and updating a single status bit which has a particular binary value when the logical output queue's status is &#x201c;not clear to release&#x201d; and the opposite binary value when the logical output queue's status is &#x201c;clear to release&#x201d;. Outputs generate (but do not transmit) release grants in a logical order determined by running a grant generation algorithm. Inputs release discrete information units in a logical order determined by running a release algorithm. Status messages for logical output queues are re-transmitted when extra bandwidth is available to remove any inaccurate view of the status of the logical output queues resulting from transmission failures of the original status messages.

Input buffering and queue status-based output control for a digital traffic switch

A digital traffic switch having DIBOC buffer control has a queue status-based control strategy to limit status traffic on the switch and status buffer requirements. Status messages are transmitted from inputs to outputs when the content status of a logical output queue has changed from &ldquo;empty&rdquo; to &ldquo;not empty&rdquo;, or vice versa, rather than on a &ldquo;per cell&rdquo; request basis. Status messages are transmitted from outputs to inputs when the clearance status of a logical output queue has changed from &ldquo;not clear to release&rdquo; to &ldquo;clear to release&rdquo;, or vice versa, rather than on a &ldquo;per cell&rdquo; grant basis. The status of each logical output queue is monitored at outputs by retaining and updating a single status bit which has a particular binary value when the logical output queue's status is &ldquo;empty&rdquo; and the opposite binary value when the logical output queue's status is &ldquo;not empty&rdquo;. The status of each logical output queue is monitored at inputs by retaining and updating a single status bit which has a particular binary value when the logical output queue's status is &ldquo;not clear to release&rdquo; and the opposite binary value when the logical output queue's status is &ldquo;clear to release&rdquo;. Outputs generate (but do not transmit) release grants in a logical order determined by running a grant generation algorithm. Inputs release discrete information units in a logical order determined by running a release algorithm. Status messages for logical output queues are re-transmitted when extra bandwidth is available to remove any inaccurate view of the status of the logical output queues resulting from transmission failures of the original status messages.

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Channel Islands Harbor, CA, United States of America

Chris L Hoogenboom