SCHEDULING MEANS FOR DATA SWITCHING APPARATUS

摘要

Scheduling means is provided for data switching apparatus having a plurality of input ports and a plurality of output ports between which data having one of a predetermined number of priority levels is to be passed. The scheduling means includes a first pipeline stage (10) to which are applied requests for said interconnections from the input ports and operable to satisfy at least some of the requested interconnections. A priority mixer (13) is provided to which are applied those requests for interconnections which were not satisfied by the first pipeline stage together with requests of a different priority level. The priority mixer (13) operates to select which of those requests should be further considered and applied to a second pipeline stage (11). This is operable to satisfy such of those requests as are possible. Further pipeline stages (12) are provided, to which are applied those requests not satisfied by any preceding pipeline stages.