摘要 |
A scheduler for a packet switch capable of atomic multicasts, that is, allowing one packet at an input port to be simultaneously transmitted to multiple output ports. The scheduling algorithm sequentially polls each of the input ports to determine to which output ports it desires connection for the next transmission slot. If those output ports are available, that input port assigns itself to the slot, and subsequent input ports are blocked from those output ports. The scheduling algorithm does not poll these blocked input ports for the current slot. The scheduler can be advantageously implemented in an optical system having one optical path for indexing control and multiple optical paths corresponding to each of the output ports. Sub-schedulers are arranged serially along all the optical paths. When a sub-scheduler is notified by the indexing control path that its turn to assign has arrived, it checks all of the optical paths corresponding to the output ports to which it desires connection. If those output ports are available, it assigns itself to the current slot, indicates on the output port optical paths that those desired output ports are no longer available, and indicates on the indexing control path that its assigning turn is over. If those output ports are not available, it nonetheless indicates on the indexing control path that its assigning turn is over and waits till the next assigning period.
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