Data switch and a method for controlling the data switch
AssigneeXyratex Technology Limited
InventorsMarek Stephen Piekarski, Paul Graham Howarth, Yves Tchapda
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Abstract
A data switch is proposed of the type having virtual queue ingress routers interconnected with egress routers by way of a memoryless switching matrix controlled by a control unit which performs an arbitration process to schedule connections across the switch. This scheduling is performed to ensure that data cells which arrive at the ingress routers at unpredictable times are transmitted to the correct egress routers. Each ingress router further includes a queue for time division multiplex traffic, and at times when such traffic exists, the control unit overrides the arbitration process to allow the time division multiplex traffic to be transmitted through the switch.
Claims12
A data switching system having a plurality of virtual output queue ingress routers, a plurality of egress routers, a control unit, and a memory-less switching matrix for interconnecting selected ingress routers and egress routers,
- the ingress routers being arranged to receive data traffic segregated into equal sized cells having a header including an egress router output path address, to route the cells into virtual output queues in the ingress router in accordance with the egress router output path address and to generate connection requests for transmission to the control unit,
- the control unit being arranged to arbitrate among the connection requests and control the switching matrix to schedule the connections across the switch,
- characterised in that a separate queue is provided in each ingress router for time division multiplex traffic segmented into a plurality of standard cells and the control unit includes a time division multiplex connection unit arranged to override the normal arbitration procedure for each time division multiplex frame and to provide the switch connections for the cells of the time division multiplex frame.
A data switching method for controlling a data switch having a plurality of virtual output queue ingress routers, a plurality of egress routers, a control unit, and a memory-less switching matrix for interconnecting selected ingress routers and egress routers,
- the ingress routers being arranged to receive data traffic segregated into equal sized cells having a header including an egress router output path address, to route the cells into virtual output queues in the ingress router in accordance with the egress router output path address and to generate connection requests for transmission to the control unit,
- the control unit being arranged to arbitrate among the connection requests and control the switching matrix to schedule the connections across the switch,
- characterised in that the method includes:
- providing a separate queue in each ingress router for time division multiplex traffic segmented into a plurality of standard cells;
- and
- using a time division multiplex connection unit to override the normal arbitration procedure for each time division multiplex frame to provide the switch connections for the cells of the time division multiplex frame.
Dependencies are inferred from the claim text.