Cisco Technology, Inc.

Hewlett-Packard Development Company, L.p.

Michael A Benning

Mick R Jacobs

David Walker

Matthew Todd Lawson

Kenneth Michael Rose

David Edward Bliss

Network switching and/or routing devices can use multiple priority data streams and queues to support prioritized serial transmission of data from line cards (or the like) through a fabric switch to other line cards (or the like). Preemption logic is used to insert within a data stream commands indicating a switch from one priority level data to another. Delimiter commands and combination switch/delimiter commands can also be used. Multiple crossbars are implemented in the fabric switch to support the various data stream priority levels.

Prioritization and preemption of data frames over a switching fabric

A reference signal of reference pulses occurring at a uniform reference pulse rate is received. An error event signal of error event pulses occurring at a variable error event pulse rate corresponding to a rate of detected error event occurrences is received. An integrator output signal is produced from the reference signal and the error event signal. The integrator output signal has a value that approaches a first boundary threshold when the reference pulse rate exceeds the error event pulse rate and approaches a second boundary threshold when the error event pulse rate exceeds the reference pulse rate. A decision signal is set to a first value in response to a determination that the value of the received integrator output signal meets a first decision threshold and set to a second value in response to a determination that the value of the received integrator output signal meets a second decision threshold.

Communications link health monitoring

An apparatus including a first buffer, a second buffer and a priority switch circuit. The first buffer is configured to store data of a first data stream having a first priority. The second buffer is configured to store data of a second data stream having a second priority. The priority switch circuit is coupled to the first buffer and the second buffer and is configured to interrupt a transmission of the first data stream from the first buffer upon detection of data of the second data stream and transmit data of the second data stream.

System and method for switching high priority traffic with low latency

Network switching and/or routing devices can use switching fabrics that gather information about output port buffer status and distribute that information to various line cards for use in data frame congestion avoidance. The switching fabric can gather output buffer status information for all output ports and distribute that information to each line card in an efficient, in-band manner. Individual line cards can use the information to determine from which line card virtual output queue to dequeue data frames destined for the switching fabric. Line cards can also gather output buffer status information associated with line card queues used for receiving data from the switching fabric. Such data is used in a manner similar to the output buffer data from the switching fabric.

Apparatus and method for distributing buffer status information in a switching fabric

Disclosed is a method and apparatus for synchronizing data in a number of separate integrated circuits. In one embodiment, the apparatus includes a first integrated circuit configured to receive first data, and a second integrated circuit coupled to the first integrated circuit configured to receive second data. The second integrated circuit is separate from the first integrated circuit. The second integrated circuit is further configured to synchronize the second data with the first data. In another embodiment, the apparatus includes a first integrated circuit configured to receive first data, and a second integrated circuit coupled to the first integrated circuit configured to receive second data. The second integrated circuit is separate from the first integrated circuit. The second integrated circuit is further configured to detect when the second data is out of synchronization with the first data.

Distributed data synchronization apparatus and method

Disclosed is a method and apparatus for synchronizing data. In one embodiment, the apparatus includes a first communication link for transmitting first data and a second communication link for transmitting second data. A circuit coupled to the first and second communication links. The circuit is configured to receive the first and second data. The circuit is configured to synchronously output the first and second data when the first and second data are received by the circuit out of synchronization.

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Roseville, CA, United States of America

Michael A Benning