| 摘要 |
<p>A scheduling and arbitration arrangement is provided for use in a digital switching system comprising a central switch under the direction of a master control to provide the cross-connections between a number of high-bandwidth input and output ports. On the ingress side of the switch are provided a number of ingress multiplexers, one for each high-bandwidth input port, whilst on the egress side of the switch are a number of egress multiplexers, one for each high-bandwidth output ports. Each ingress multiplexer includes a set of N input queues serving N low-bandwidth data sources and a set of M virtual output queues, one for each low-bandwidth output data source. The scheduling and arbitration arrangement includes three bandwidth allocation tables. One of these, the ingress port table, is associated with the input queues having NxM entries, each arranged to define the bandwidth allocation for a particular virtual output queue. A second table is the egress port table, associated with the virtual output queues having M entries, each arranged to define the bandwidth allocation of a high-bandwidth port of the central switch to a virtual output queue. The third table is the central allocation table, located in the master control and having (M/N)2 entries, each of which specifies the weights allocated to each possible connection through the central switch.</p> |
