CONTROLLING BANDWIDTH ALLOCATION USING A PACE COUNTER

摘要

A method and apparatus is disclosed for allocating bandwidth within a network switch having a plurality of input ports (14) coupled to a plurality of output ports (16) through a switch fabric (9) to assure that a minimum bandwidth is allocated for determined scheduling lists. A switch allocation table is provided for each of a plurality of input ports. Each switch allocation table is organized as a circular table which is sequentially indexed via an associated index counter. Respective entries in the switch allocation table comprise scheduling list numbers which serve to identify cells requiring switch bandwidth. The respective index counters are synchronized such that all switch allocation tables have a corresponding entry selected. The amount of bandwidth and delay through the network switch is controlled for each of the scheduling lists based upon the number and spacing of entries in the respective switch allocation table. Latency through the network switch is significantly reduced via the use of a pace counter and a pace limit which, in cooperation with the switch allocation table, determine whether a cell associated with a particular scheduling list may be dispatched through the switch fabric (9) for transmittal onto a network link by at least one of the output ports (16).