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AssigneeXyratex Technology Limited
InventorsIan David Johnson, Simon William Farrow, Marek Stephen Piekarski, Paul Graham Howarth
Estimating the term…
In a data switching system, the ingress and egress ports of a memoryless cross-bar switch are controlled by an arbitration method. The arbitration method uses a three phase process involving (i) a request phase in which each ingress port sends its connection requests to egress ports to which a connection is required, (ii) a grant phase in which each egress port uses a grant pointer to select one of the requests directed to it using a grant pointer, and generates a grant signal, and (iii) an accept phase in which each ingress port selects one of the received grant signals to accept, so defining an ingress to egress port connection across the cross-bar switch. The transition sequences for each of the grant pointers are mutually exclusive, so that any synchronisation of the grant pointers is eliminated on the next arbitration cycle. This is arranged by a setting of the paths taken by request and grant signals.
An arbitration method for use in selecting the connections to be made between ingress and egress ports of a memoryless cross-bar switch of a data switching system, the arbitration method comprising a three phase process involving (i) a request phase in which each ingress port sends its connection requests to the egress ports to which a connection is required, (ii) a grant phase in which each egress port examines in a round-robin manner the requests directed to it using a grant pointer, and selects one request for grant returning a grant signal indicative of the selected request and directed to the ingress port which sent the selected request, and (iii) an accept phase in which each ingress port examines in a round-robin manner the received grant signals and selects one to accept thereby defining an ingress to egress port connection across the cross-bar switch, characterized in that the transition sequences for each of the grant pointers are mutually exclusive;
An arbitration unit for use as a data switching system comprising a plurality of ingress ports, a plurality of egress ports, a memory-less cross-bar switch and said arbitration unit for controlling the switch, the arbitration unit comprising:
Dependencies are inferred from the claim text.