US 6,195,335 B1Granted

Data switch

AssigneeInternational Business Machines Corporation

InventorsJean Calvignac, Daniel Orsatti, Gilles Toubol, Fabrice Verplanken, Claude Basso

Life of this patent

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Abstract

A packet data switch is described comprising a crossbar switch fabric including a set of crosspoint buffers for storing at least one data packet, one for each input/output pair. An input queue is provided for each input-output pair and means are provided for storing incoming data packets in one of the queues corresponding to an input-output routing for the data packet. An input scheduler repeatedly selects one queue from the plurality of queues at each input and a data packet is transferred from the queue selected by the input scheduler from the input queue means to the crosspoint buffer corresponding to the input-output routing for the data packet. A back pressure mechanism is arranged to inhibit selection by the first selector of queues corresponding to input/output pairs for which the respective crosspoint buffer is full. Finally, an output scheduler repeatedly selects for each output one of the crosspoint buffers corresponding to the output and the switch is responsive to the output scheduler to complete the transmission through the switch fabric of the data packet stored in the crosspoint buffer selected by the output scheduler.

Claims5

Dependent claims

A packet data switch having a plurality of inputs and a plurality of outputs, the switch comprising:

a crossbar switch fabric for directing data packets between any one of the inputs and any one of the outputs, the switch fabric including a set of crosspoint buffers, one for each input/output pair, each for storing at least one data packet;
input queue means comprising a queue for each input-output pair and means for storing incoming data packets in one of the queues according to a routing for the data packet;
an input scheduler for repeatedly selecting one queue from the plurality of queues at each input;
means to transfer a data packet from the queue selected by the input scheduler from the input queue means to the crosspoint buffer corresponding to the input-output pair for the queue;
a back pressure mechanism arranged to inhibit selection by the input scheduler of queues corresponding to input/output pairs for which the respective crosspoint buffer is full;
and an output scheduler for repeatedly selecting for each output one of the crosspoint buffers corresponding to the output,
the switch being responsive to the output scheduler to complete the transmission through the switch fabric of the data packet stored in the crosspoint buffer selected by the output scheduler.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/110,917Filed 6 Jul 1998
Priority: EP 9748004127 Jun 1997
Granted: 27 Feb 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04L 12/5601
Packet switching systems: transfer mode dependent, e.g. ATM
H04L 49/1576
Interconnection of ATM switching modules, e.g. ATM switching fabrics: crossbar or matrix
H04L 2012/5679
Traffic aspects, e.g. arbitration, load balancing, smoothing, buffer management: arbitration or scheduling
H04L 2012/5681
Traffic aspects, e.g. arbitration, load balancing, smoothing, buffer management: buffer or queue management