Method and apparatus for data buffer management in a communications switch

Abstract

A method and apparatus is for buffering data cells in a queuing element is presented. Each queuing element includes a partitioned buffer, where the partitioned buffer includes a plurality of partitions. Each of the partitions stores data cells received by the queuing element. Storage of the data cells into the partitions is accomplished by using an array of logical queues. Each logical queue of the array of logical queues maps data cells corresponding to that logical queue to a particular partition of the plurality of partitions. More than one logical queue may map data cells to a particular partition. Each partition may include a reserved portion, where each logical queue that maps to the partition may map a portion of its data cells to the reserved portion. The resources of the reserved portion to which a logical queue maps data cells are reserved to that specific logical queue and cannot be utilized by other logical queues. Each partition also includes a shared portion, where all of the logical queues that map to a partition are able to utilize the storage space included in the shared portion. Each logical queue includes a maximum size. Depth pointers corresponding to the logical queue and the partition are updated as data cells are enqueued to, and dequeued from, the logical queue.